TJ
381
F829f
ENGINEERING &
MATHEMATICAL
SCIENCES LIBRARY
RS' HISTORY O
THE LIBRARY
OF
THE UNIVERSITY
OF CALIFORNIA
LOS ANGELES
GIFT OF
Ogden Collection
\
\-
E. GREEN & SON LTD.
Sole Makers and Original Inventors of
GREEN'S PATENT
FUEL ECONOMISER
2 EXCHANGE ST. MANCHESTER
WORKS
WAKEFIELD YORKSHIRE ENGLAND
AND
MATTEAWAN N.Y. U.S.A.
Telegraphic Addresses Telephone Nos.
"ECONOMISER MANCHESTER" MANCHESTER NO. 1375
"ECONOMISER WAKEFIELD" WAKEFIELD No. 43
AND AT
LONDON GLASGOW BIRMINGHAM BRUSSELS MULHOUSE
ROUEN MOSCOW VIENNA & JOHANNESBURG.
LIST OF CONTENTS
INTRODUCTION ..................... 1-3
THE INVENTOR OF THE ECONOMISER ............. 4-6
Biographical Sketch of the late Mr. Edward Green.
THE FIRST EXPERIMENTAL ECONOMISER ............ 7-9
THE DEVELOPMENT OF GREEN'S ECONOMISER ........... 10-34
The first Economiser Patent, Scrapers for Economiser Tubes, Driving
and Reversing Gear for Scrapers, Lids and Seatings for Economiser
Tubes, Sectional Top and Bottom Boxes, Economiser Bottom Boxes,
Economiser with Feed Downflow.
OTHER ECONOMISER INVENTIONS ............... 35-?°
Lees' Steam Brush, Whitehead's Steam Brush, Twibill's Circulator,
Mannock's Scraper, Robinson's Scraper, Whitehead's Chain Scraper,
Holt &* Galloway's Continuous Economiser, Needham's Scraper, Screw
Shaft and Reversing Gear, Obach's Tube Joints, Reversing Gear and
Scrapers, Bell's Spiral Economiser, Mundy's Scraper, Calvert e^ Taylor's
Continuous Economiser, Elson's Bottle Economiser, Lees &° Garforth's
Scraper and Continuous Economiser, Twibill's Circular Economiser,
Mason &* Alcock's Continuous Economiser, Prestwich &* Pimbley's
Split-tube Economiser, Bell's Continuous Economiser, Sykes" Group
Economiser, Lowcock &* Taylor's Scrapers, Perkins and Scott's Scrapers
and Lids, Lowcock &* Sykes' Blow-out Pipes, Bell's Continuous
Economiser, Hawkin's Top and Bottom Boxes, Lowcock &° Sykes'
Bottom Boxes, Twibill's Internal Tube Economiser, Sykes' Economiser
Lid, Burpee's Spigot Joints and Tapered Tubes, Sykes' Tapered Tubes,
Topham's Double-tube Boxes, Sankey's Continuous Economiser, Calvert's
Continuous Economiser, Sykes' Screwed Lids, Sykes' Internal Tube
Economiser, Knight &* Thode's Economiser.
ECONOMISERS HAVING CONTINUOUS CIRCULATION ......... 7l~74
Comparative tests of Circulating Economisers, by J. F. L. Crossland,
M. Inst. C.E. ; Michael Longridge, M. Inst. C.E. ; L. E. Fletcher,
M. Inst. C.E. ; E. G. Hiller, M. Inst. M.E.
CIRCULATORS AND ECONOMISERS .............. 75-76
GREEN'S EARLY TUBULAR BOILERS .............. 77-91
Saddle Boilers with Single and Double Tubular Legs, Egg-ended Multi-
tubular Boilers, Vertical Tubular Boilers, Sectional Furnace Boiler,
Economisers worked as Boilers, Internally-fired Tubular Boilers, Cone
Tube Boiler.
GREEN'S EARLY SUPERHEATERS ............... 92-93
GREEN'S MODERN FUEL ECONOMISER .............. 94-101
Quick Reversing Gear for Scrapers, Independent Engine for driving
Scrapers, External Lids for ordinary pressures, Internal Lids for high
pressures, Method of withdrawing Damaged Tubes, Access Lids.
SIZE AND EFFICIENCY OF GREEN'S ECONOMISER ....... . . I02-IO5
DIRECTIONS FOR WORKING ECONOMISER ............ Io6-lo8
CONCLUSION ...................... 109
INDEX
ACCESS LIDS FOR FLUSHING GREEN'S ECONOMISER 105
AGITATOR FOR BOTTOM BOXES, GREEN'S 1 6, 32
AIR BRUSH, WHITEHEAD'S 38
ALCOCK AND MASON'S ECONOMISER 54
B
BELL'S CONTINUOUS ECONOMISER 56, 60
BELL'S SPIRAL ECONOMISER 47
BLOW-OUT ARRANGEMENTS, LOWCOCK AND SYKES' 60
BOILERS, GREEN'S TUBULAR 77
BOILERS, NUMBER FITTED WITH GREEN'S ECONOMISER 3
BOTTLE ECONOMISER, ELSON'S 49
BOTTOM BOXES, GREEN'S AGITATOR 1 6, 32
BOXES FOR ECONOMISERS, HAWKINS' 62
BOXES FOR ECONOMISERS, LOWCOCK AND SYKES' 59, 64
BOXES, TOPHAM'S DOUBLE TUBE 67
BRUSH, LEES' STEAM 36
BRUSH, WHITEHEAD'S STEAM AND AIR 38
BURPEE'S SPIGOT JOINTS AND TAPERED TUBES 66
C
CALLIPER SCRAPER, ROBINSON'S 40
CALVERT AND TAYLOR'S ECONOMISER 49
CALVERT'S CONTINUOUS CIRCULATION ECONOMISER 68
CAPS FOR ECONOMISER TUBES (see LIDS)
CHAIN SCRAPER, WHITEHEAD'S 40
CIRCULATOR, TWIBILL's 38
CIRCULATORS versus ECONOMISERS 75
CONDENSER, WATTS's ANALOGOUS TO GREEN'S ECONOMISER 2
CONDENSER, GREEN'S 80
CONTINUOUS CIRCULATION ECONOMISER, BELL'S 56, 60
CONTINUOUS CIRCULATION ECONOMISER, CALVERT'S 68
CONTINUOUS CIRCULATION ECONOMISER, CALVERT AND TAYLOR'S 49
CONTINUOUS CIRCULATION ECONOMISER, HOLT AND G ALLOW AY*S 41
CONTINUOUS CIRCULATION ECONOMISER, KNIGHT AND THODE'S 7O
viii. INDEX
PAGE
CONTINUOUS CIRCULATION ECONOMISED LEES' 36
CONTINUOUS CIRCULATION ECONOMISER, LEES AND GARFORTH's 52
CONTINUOUS CIRCULATION ECONOMISER, MASON AND ALCOCK's 54
CONTINUOUS CIRCULATION ECONOMISER, SANKEY'S 68
CONTINUOUS CIRCULATION ECONOMISERS, TESTS OF 71
CRAB JAW SCRAPERS, PERKINS AND SCOTT'S 59
D
DOUBLE TUBE BOXES, TOPHAM's 67
DOWN FEED ECONOMISER, GREEN'S 3°) 33
E
ECONOMISER, BELL'S . . 47, 56, 60
ECONOMISER, CALVERT AND TAYLOR'S 49
ECONOMISER, CALVERT'S CONTINUOUS CIRCULATION 68
ECONOMISER, ELSON'S 49
ECONOMISER, GREEN'S FIRST EXPERIMENTAL 7
ECONOMISER, GREEN'S FIRST PATENTED IO
ECONOMISER, GREEN'S MODERN 94
ECONOMISER, HOLT AND GALLOWAY'S CONTINUOUS CIRCULATION 41
ECONOMISER, KNIGHT AND THODE's 70
ECONOMISER, LEES AND GARFORTH'S 52
ECONOMISER, LEES' CONTINUOUS CIRCULATION 36
ECONOMISER MADE OF SEPARATE TUBES, GREEN'S 31
ECONOMISER, MASON AND ALCOCK's 54
ECONOMISER, OBACH's 45
ECONOMISER, PRESTWICH AND PIMBLEY's 56
ECONOMISER, SANKEY'S 68
ECONOMISER, SYKES* GROUPED TUBE 57
ECONOMISER, SYKES' INTERNAL TUBE 69
ECONOMISER, TOPHAM's 67
ECONOMISER, TWIBILL'S CIRCULAR 54
ECONOMISER, TWIBILL'S INTERNAL TUBE 65
ECONOMISER WITH FEED DOWNFLOW, GREEN'S 3°j 33
ECONOMY EFFECTED BY GREEN'S ECONOMISERS 6
ELSON'S BOTTLE ECONOMISER 49
ELSON'S SPIRAL SCRAPER 51
EXPERIMENTAL ECONOMISER, GREEN'S FIRST CONSTRUCTION 7
EXPLOSION OF CONTINUOUS CIRCULATION ECONOMISER 42
F
FEED DOWNFLOW 3O, 33
FLUTED ECONOMISER TUBES 8 1
FUEL, SAVING EFFECTED BY GREEN'S ECONOMISERS 6
INDEX
GALLOWAY'S CONTINUOUS CIRCULATION ECONOMISER . . 41
GARFORTH AND LEES' CONTINUOUS CIRCULATION ECONOMISER 52
GARFORTH AND LEES1 SCRAPERS 51
GREEN, BIOGRAPHICAL SKETCH 4
GREEN'S AGITATOR FOR BOTTOM BOXES 32
GREEN'S ECONOMISER, DIRECTIONS FOR WORKING 106
GREEN'S ECONOMISER, ECONOMY EFFECTED BY 6
GREEN'S ECONOMISER INTERNAL BLOCKS AND TUBES 16
GREEN'S ECONOMISER JUBILEE 2
GREEN'S ECONOMISER, METHOD OF FLUSHING 104
GREEN'S ECONOMISER, NOTES ON SIZE AND EFFICIENCY OF 102
GREEN'S ECONOMISER, NUMBER OF BOILERS FITTED WITH 3
GREEN'S ECONOMISER WITH FEED DOWNFLOW ... 30, 33
GREEN'S EXTERNAL LID FOR ORDINARY PRESSURES 99
GREEN'S FIRST EXPERIMENTAL ECONOMISER 7
GREEN'S FIRST PATENTED ECONOMISER 10
GREEN'S FIRST SCRAPERS 15
GREEN'S FIRST SECTIONAL SCRAPER 17
GREEN'S INDEPENDENT ENGINE FOR DRIVING SCRAPERS 98
GREEN'S INTERNAL LID FOR HIGH PRESSURES 100
GREEN'S LID WITH COPPER-JOINT RING 29
GREEN'S LID WITH DRAW SCREW 26
GREEN'S LID WITH SOFT METAL COLLAR FOR BOLT 26
GREEN'S LID WITH TRIANGULAR BOLTS 28
GREEN'S LIDS FOR ECONOMISER TUBES ... 25
GREEN'S METHOD OF DRAWING AND PLUGGING DAMAGED TUBES 101
GREEN'S MODERN ECONOMISER 94
GREEN'S OVAL AND INTERNAL LIDS 28
GREEN'S OVAL LID WITH CONE JOINT FACE 29
GREEN'S QUICK REVERSING MOTION 97
GREEN'S REVERSING GEAR FOR SCRAPERS 22
GREEN'S SCRAPER WITH BALL HINGE 18
GREEN'S SCRAPER WITH DIAGONAL TEETH 20
GREEN'S SECTIONAL INTERLOCKING SCRAPER 21
GREEN'S SEPARATE TUBE ECONOMISER 31
GREEN'S EARLY TUBULAR BOILERS * 77
GREEN'S EARLY SUPERHEATERS 92
GUNPOWDER USED TO REMOVE SOOT -FROM ECONOMISER TUBES 9
H
HAWKINS' TOP AND BOTTOM BOXES 62
HOLT'S CONTINUOUS CIRCULATION ECONOMISER . , 41
INDEX
INCLINED TUBE ECONOMISER, BELL'S 56
INSTRUCTIONS FOR WORKING ECONOMISER .... 106
INTERNAL BLOCKS AND TUBES IN GREEN'S ECONOMISER 1 6
INTERNAL TUBE ECONOMISER, SYKES' 69
INTERNAL TUBE ECONOMISER, TWIBILL's 65
J
JOINT FOR ECONOMISER TUBES, OBACH's 45
JUBILEE OF INVENTION OF ECONOMISER 2
K
KNIGHT AND THODE'S CIRCULATION ECONOMISER 70
L
LEES' STEAM BRUSH 36
LEES AND GARFORTH'S CONTINUOUS CIRCULATION ECONOMISER 52
LEES AND GARFORTH'S SCRAPERS 51
LID, SYKES' ECONOMISER 66
LID WITH COPPER-JOINT RING 29
LID WITH DRAW SCREW, GREEN'S 26
LID WITH SOFT COLLAR FOR BOLT, GREEN'S 26
LID WITH TRIANGULAR BOLT, GREEN'S 28
LIDS FOR ECONOMISER TUBES, GREEN'S 25
LIDS FOR ECONOMISERS, SYKES' SCREWED 69
LIDS FOR HIGH PRESSURES, GREEN'S INTERNAL IOO
LIDS FOR ORDINARY PRESSURES, GREEN'S EXTERNAL 99
LIDS, GREEN'S OVAL AND INTERNAL 28
LIDS, OVAL, WITH CONE JOINT FACE, GREEN'S 29
LIDS, PERKINS AND SCOTT'S t
LOWCOCK AND SYKES BLOW-OUT ARRANGEMENTS
59
LOWCOCK AND SYKES' BOXES FOR ECONOMISERS 59, 64
LOWCOCK AND TAYLOR'S SCRAPERS c8
M
MANNOCK'S SCRAPER 40
MASON AND ALCOCK's ECONOMISER 54
MUNDY'S SCRAPERS 48
N
NEEDHAM'S INCLINED SCRAPERS 42
NEEDHAM'S REVERSING MOTION FOR SCRAPERS 43
NEEDHAM'S SCREW SHAFT
NUMBER OF ECONOMISERS MADE BY MESSRS. GREEN 3
INDEX
OBACH'S TUBE JOINTS . 45
OBACH'S REVERSING MOTION FOR SCRAPERS 46
OBACH'S SCRAPERS 45
P
PERKINS AND SCOTT'S LIDS 59
PERKINS AND SCOTT'S SCRAPERS 59
PRESTWICH AND PIMBLEY's ECONOMISER 56
R
REVERSING GEAR FOR SCRAPERS, GREEN'S 22
REVERSING MOTION FOR SCRAPERS, NEEDHAM'S 43
REVERSING MOTION, GREEN'S QUICK 97
ROBINSON'S SCRAPER 40
S
SANKEV'S ECONOMISER 68
SCOTT AND PERKINS' SCRAPERS 59
SCRAPER, BELL'S 47
SCRAPER, ELSON'S SPIRAL 51
SCRAPER, GREEN'S FIRST SECTIONAL 17
SCRAPER, GREEN'S SECTIONAL INTERLOCKING 21
SCRAPER, MANNOCK'S 40
SCRAPER, MUNDY'S 48
SCRAPER, OBACH'S ; 45
SCRAPER, OBACH'S REVERSING MOTION FOR 46
SCRAPER, PERKINS AND SCOTT's CRAB JAW 59
SCRAPER, ROBINSON'S 40
SCRAPER WITH BALL HINGE, GREEN'S 1 8
SCRAPER WITH DIAGONAL TEETH, GREEN'S 2O
SCRAPERS, GREEN'S FIRST 15
SCRAPERS, GREEN'S INDEPENDENT DRIVING ENGINE FOR 98
SCRAPERS, GREEN'S QUICK REVERSING MOTION FOR 97
SCRAPERS, GREEN'S REVERSING GEAR FOR 22
SCRAPERS, LEES AND GARFORTH'S 51
SCRAPERS, LOWCOCK AND TAYLOR'S 58
SCRAPERS, NEEDHAM'S INCLINED 42
SCRAPERS, NEEDHAM'S REVERSING MOTION FOR 43
SCRAPERS, PERKINS AND SCOTT'S 59
xii. INDEX
PAGE
SCRAPERS, WHITEHEAD'S CHAIN 40
SCREW SHAFT, NEEDHAM's 43
SEPARATE CONDENSER, WATTS', ANALOGOUS TO GREEN'S ECONOMISER ... 2
SPIGOT JOINTS, BURPEE'S 66
SPIRAL ECONOMISER, BELL'S 47
STAGGERED TUBES, BELL'S ECONOMISER 60
STAGGERED TUBES, TOPHAM'S 67
STAGGERED ROWS OF TUBES USED IN GREEN'S FIRST ECONOMISER .... 12
STEAM BRUSH, LEES' 36
STEAM BRUSH, WHITEHEAD'S 38
SUPERHEATERS, GREEN'S 92
SYKES AND LOWCOCK/S BLOW-OUT ARRANGEMENTS 59
SYKES AND LOWCOCK's BOXES FOR ECONOMISERS 59, 64
SYKES' ECONOMISER LID 66
SYKES' GROUP ECONOMISER 57
SYKES' INTERNAL TUBE ECONOMISER 69
SYKES' SCREWED LIDS 69
SYKES' TAPERED ECONOMISER TUBES . 67
T
TAYLOR AND CALVERT'S ECONOMISER 49
TAYLOR AND LOWCOCK's SCRAPERS 58
TAPER ECONOMISER TUBE, BURPEE'S 66
TAPER ECONOMISER TUBE, SYKES' 67
TESTS OF CONTINUOUS CIRCULATION ECONOMISERS 71
THODE AND KNIGHT'S CIRCULATION ECONOMISER 70
TOPHAM'S DOUBLE TUBE BOXES 67
TUBES, GREEN'S METHOD OF WITHDRAWING DAMAGED 101
TUBE JOINT, OBACH'S 45
TUBES, TAPERED, BURPEE 66
TUBES, TAPERED, SYKES' 67
TUBULAR BOILERS, GREEN'S 77
TWIBILL'S CIRCULAR ECONOMISER 54
TWIBILL'S CIRCULATOR 38
TWIBILL'S INTERNAL TUBE ECONOMISER 65
W
WATER-TUBE BOILERS, GREEN'S 77
WATTS' SEPARATE CONDENSER ; ANALOGOUS TO GREEN'S ECONOMISER ... 2
WHITEHEAD'S STEAM AND AIR BRUSH 38
WHITEHEAD'S CHAIN SCRAPER 40
WORKING OF ECONOMISER, INSTRUCTIONS FOR . Io6
LIST OF ILLUSTRATIONS
PAGE
FIG. I. LONGITUDINAL SECTION OF FIRST EXPERIMENTAL ECONOMISER . . 8
FIG. 2. PLAN OF FIRST EXPERIMENTAL ECONOMISER 8
FIG. 3. LONGITUDINAL SECTION OF GREEN'S FIRST PATENTED ECONOMISER . 1 1
FIG. 4. PLAN OF GREEN'S FIRST PATENTED ECONOMISER 12
FIG. 5. ELEVATION OF SCRAPERS IN FIRST ECONOMISER 13
FIG. 6. PLAN OF SCRAPERS IN FIRST ECONOMISER 14
FIG. 7. FIRST SECTIONAL SCRAPER 17
FIG. 8. SECTIONAL SCRAPERS WITH BALL HINGE 1 8
FIG. 9. PLAN OF SCRAPER 19
FIG. 10. SECTION OF SCRAPER 19
FIG. II. SCRAPER WITH DIAGONAL CUTTING TEETH 2O
FIG. 12. SECTIONAL INTERLOCKING SCRAPER 21
FIG. 13. ELEVATION OF SCRAPER REVERSING GEAR 22
FIG. 14. PLAN OF SCRAPER REVERSING GEAR 22
FIG. 15. END VIEW OF SCRAPER REVERSING GEAR 23
FIG. 1 6. END VIEW OF QUICK REVERSING GEAR 24
FIG. 17. PLAN OF QUICK REVERSING GEAR 24
FIG. l8. INTERNAL CONICAL LID 26
FIGS. 19 6- 20. SOFT METAL COLLAR FOR SEALING BOLT HOLE OF LID . . 27
FIG. 21. TRIANGULAR BOLT FOR ECONOMISER LID 28
FIG. 22. OVAL INTERNAL LID 28
FIG. 23. INTERNAL LID WITH COPPER JOINT RING 29
FIG. 24. INTERNAL OVAL LID WITH CONICAL JOINT FACE 29
FIG. 25. ECONOMISER WITH FEED DOWN FLOW 30
FIG. 26. ECONOMISER BUILT UP OF SEPARATE TUBES 3]
FIG. 27. BOTTOM BOX WITH MECHANICAL AGITATOR 32
FIG. 28. ECONOMISER WITH FEED DOWNFLOW 33
FIG. 29. LEES' REVOLVING STEAM BRUSH 36
FIG. 30. SECTION OF TWIBILL'S SUPPLEMENTARY HEATER 38
FIG. 31. PLAN OF TWIBILL'S SUPPLEMENTARY HEATER 39
FIG. 32. MANNOCK'S SCRAPER 40
FIG. 33. ROBINSON'S SCRAPER 40
FIG. 34. HOLT AND GALLOWAY'S CONTINUOUS ECONOMISER 41
FIG. 35. NEEDHAM'S SCREW SHAFT 43
FIG. 36. NEEDHAM'S REVERSING MOTION FOR SCRAPERS 44
FIG. 37. OBACH'S TUBE JOINT 45
FIG. 38. OBACH'S SCRAPER 46
LIST OF ILLUSTRATIONS
PAGE
FIG. 39. OBACH'S REVERSING GEAR . 46
FIG. 40. BELL'S SPIRAL ECONOMISER 47
FIG. 41. CALVERT AND TAYLOR'S ECONOMISER 48
FIG. 42. PLAN OF CALVERT AND TAYLOR'S ECONOMISER 49
FIG. 43. ELSON'S BOTTLE ECONOMISER 50
FIG. 44. ELSON'S SPIRAL SCRAPER , . . . . 51
FIG. 45. LEES AND GARFORTH'S CONTINUOUS CIRCULATION ECONOMISER . . 52
FIGS. 46 6° 47. TWIBILL'S CIRCULAR ECONOMISER 53
FIG. 48. MASON AND ALCOCK's CONTINUOUS CIRCULATION ECONOMISER . . 54
FIGS. 49 6- 50. PRESTWICH AND PIMBLEY'S SPLIT TUBE ECONOMISER ... 55
FIG. 51. BELL'S CONTINUOUS CIRCULATION ECONOMISER 57
FIG. 52. SYKES' GROUPED TUBE ECONOMISER 58
FIG. 53. PERKINS AND SCOTT?S CRAB JAW SCRAPERS 59
FIGS. 54 6" 55. LOWCOCK AND SYKES' BLOW-OUT ARRANGEMENTS .... 60
FIGS. 56 6° 57. BELL'S CONTINUOUS CIRCULATION ECONOMISER 61
FIGS. 58 6° 59. HAWKINS' TOP AND BOTTOM BOXES 62
FIG. 60. LOWCOCK AND SYKES' TOP AND BOTTOM BOXES 64
FIG. 61. TWIBILL'S INTERNAL CIRCULATING TUBE ECONOMISER 65
FIG. 62. SYKES' ECONOMISER LID 66
FIG. 63. TOPHAM'S DOUBLE-TUBE BOXES 67
FIG. 64. CALVERT'S ECONOMISER 72
FIG. 65. BLOW-OUT ARRANGEMENT OF CALVERT'S ECONOMISER 72
FIGS. 66 6- 67. GREEN'S TUBULAR SADDLE BOILERS 77, 78
FIGS. 68 &* 69. GREEN'S MULTITUBULAR EGG-ENDED BOILER 79
FIG. 70. GREEN'S DUPLEX-TUBULAR EGG-ENDED BOILER 80
FIGS. 71 6" 72. GREEN'S SECTIONAL BOILER WITH EXTERNAL FURNACE . . 81
FIG. 73. GREEN'S SECTIONAL FURNACE 82
FIGS. 74 6" 75. GREEN'S SECTIONAL FURNACE BOILER 83, 84
FIG. 76. ECONOMISER FITTED WITH STEAM DRUM 85
FIG. 77. GREEN'S VERTICAL TUBULAR BOILER 86
FIGS. 78 6° 79. GREEN'S TUBULAR BOILER FITTED WITH SECTIONAL FURNACE 87, 89
FIG. 80. GREEN'S INTERNALLY FIRED TUBULAR BOILER 88
FIG. 81. GREEN'S CONE TUBE BOILER 90
FIG. 82. GREEN'S EARLY SUPERHEATER 92
FIGS. 83, 84, 6- 85. GREEN'S MODERN ECONOMISER 94> 95
FIG. 86. GREEN'S REVERSING GEAR FOR SCRAPERS 97
FIG. 87. INDEPENDENT ENGINE FOR DRIVING SCRAPER 98
FIG. 88. GREEN'S EXTERNAL LID FOR ORDINARY PRESSURES 99
FIG. 89. GREEN'S INTERNAL LID FOR HIGH PRESSURES 100
FIG. 90. METHOD OF DRAWING DAMAGED TUBE AND INSERTING STOP FERRULES IOI
FIG. 91. METHOD OF FLUSHING BOTTOM BOXES 104
FIG. 92. PATENT ACCESS PIPE FOR FLUSHING ECONOMISER 105
LIST OF PLATES
FACING PAGE
GREEN'S MODERN ECONOMISED ETC TITLE
CASTING TUBES VERTICALLY
A CORNER OF THE FOUNDRY 35
A CORNER OF THE FITTING SHOP 57
SCRAPER GEAR FITTING ROOM 71
HYDRAULIC PRESSES 1 09
HISTORY OF THE ECONOMISER
INTRODUCTION
HERE is probably no adjunct in connection with the
working of Stationary Steam Boilers whose economical
value is more generally recognised than that known as
the ECONOMISER, or FEED-WATER HEATER ; and with the invention
and development of which the name of GREEN has become so
largely identified. Indeed it is no exaggeration to say that wherever
Stationary Boilers of any size or number are at work, there also
will be found a " Fuel Economises"
The apparatus consists in the main of a stack of tubes,
arranged vertically in the flue leading from the boiler to the
chimney, and designed to utilize the waste heat in the gases
2 INTRODUCTION
passing off from the furnace. This is accomplished by absorbing
the low temperature heat of the gases in heating the feed-water,
which is pumped through the Economiser in the first instance,
before its entry into the boiler.
It is this fundamental principle of heating the feed-water
in a Separate Vessel quite apart from the boiler, and thereby
utilizing the heat in the waste gases passing to the chimney, which
constitutes the distinctive feature of the first Mr. Edward Green's
invention — an invention which in its influence on boiler economy
and design is analagous, in many respects, to Watts' application
of the Separate Condenser to the Steam Engine.
It was in 1845 that the first Mr. Edward Green made his
earliest experiments with the working of this apparatus, which in
the present year enters upon its jubilee, and which is now regarded
as the almost indispensable adjunct of a steam power plant by whose
aid the surplus heat, escaping from the boilers, is arrested and
utilised.
The reputation of the apparatus is not confined to Great
Britain alone. It is in operation all over the Continent, and is as
well known in the spinning mills of Russia and India as those of
Lancashire and Yorkshire. Throughout the large manufacturing
districts of the United States it is almost universally adopted, and
is as equally noted among the gold mines of South Africa as in the
textile factories of China and Japan ; while its credit as a saver of
fuel has been so well established and its fame so widely spread,
that there is hardly a single electrical installation in this country
or the United States for lighting or traction that does not include
a Green's Economiser. Some measure of the general recognition
of the value of the Economiser is afforded by the fact that since
Messrs. Green commenced business they have supplied the
INTRODUCTION 3
apparatus to over 1 50,000 boilers, representing some thirty millions
indicated horse-power.
Having regard to the importance of the primary invention and
of the far-reaching consequences that have followed its development,
a brief outline of its first introduction and subsequent growth during
the course of fifty years will, it is thought, be of interest to that
large section of engineers who are especially associated with the
design and working of steam power installations.
A chapter has been devoted to a brief account of some early
forms of tubular boilers constructed by Messrs. Green. This has
been introduced rather as a matter of curiosity, in view of the
interest that has recently been excited in steam generators of this
type, and as showing some phases of the early development of this
class of boiler. Messrs. Green, however, are not now engaged in
the construction of tubular boilers, having given up this section of
their business some 20 years ago in order to devote themselves
solely and exclusively to the development and manufacture of the
Economiser.
THE
INVENTOR OF THE ECONOMISER
iN tracing the progress of the Economiser from the
original invention to its present development the
reader of the following pages will not fail to be
struck with the versatility and readiness of resource
displayed by the inventor in overcoming the practical difficulties
that more or less attend the development of an engineering
apparatus of this kind. As the late Mr. Edward Green was, in
many respects, a remarkable man, the following brief biographical
sketch of his career may not be out of place.
The subject of our remarks was born on the 6th of January
1799, at Wakefield, Yorkshire. His faculty for invention and
mechanical pursuits was manifested at an early age, and without
going into details it may be stated that it largely determined his
choice of a career, and he became apprenticed in due course to a
firm of engineers in the city referred to. His daily work afforded
opportunities for his inventive talents, of which he was not
slow to take advantage, and his ideas manifested themselves in a
variety of directions ranging from steam engines and agricultural
machinery to various domestic appliances. His genius for invention
was irresistible, and he appeared never satisfied unless engaged
in designing some original device or improving some existing
arrangement.
Before Mr. Green began to devote his whole time and energies
to the apparatus that bears his name, he was engaged for many
GREEN'S ECONOMIZER 5
years in general mechanical work, and in the construction of large
pumping engines for the deep coal mines of Yorkshire, as well as
others for draining the Fens in Lincolnshire and Norfolk. As
engineering work this may perhaps not be thought much of at the
present day, but it is to be remembered that at the beginning of
the present century the science of steam engineering was only in
its infancy, and the laws of heat but imperfectly understood, while
the available data as to the strength both of materials and
structures were of a very meagre character. The work of the
engineer was thus fenced round with great difficulty, and it was
frequently necessary for him to traverse untrodden ground and
rely largely on his individual experience and judgment.
In addition to his mechanical and engineering pursuits Mr.
Green displayed a considerable amount of interest and public
spirit in connection with a scheme for the supply of water for
manufacturing purposes to his native town, while the subject of
sanitary reform possessed in him a strong and ardent advocate at
a time when sanitary reformers were few, and the importance of
the subject was but imperfectly realised. One of his suggestions
in connection with this branch of engineering was that the main
sewers of large towns should be connected to a common tall
ventilating shaft, having a furnace at its base, through which
the noxious vapours could be passed in order to render them
innocuous before being discharged into the atmosphere. Soon after
the introduction of gas lighting he instituted a method for
automatically measuring and regulating the supply of gas to the
public lamps.
Though the patent for the " Fuel Economiser " was taken out
in 1845, 'li was not until after the great Exhibition of 1851 that
steam users seriously recognised the great opportunity for saving
6 GREEN'S ECONOM1SER
that was, by its means, placed within their reach. From that date,
however, its success was assured, and the large amounts of coal
that were economised by those steam users who gave it a trial,
forced it upon the attention of the remainder of the manufacturing
community, with the result that the advantages of the Economiser
became more and more widely known, and at length universally
recognised. At the present day the invention is used by boiler
owners all over the globe, and it is computed effects a saving of
upwards of one-and-a-quarter millions sterling per annum.
Mr. Edward Green died at Wakefield in the year 1865, and
was succeeded in the business he established by his son, Mr., now
Sir Edward Green, Bart., the present head of the firm, who was
joined by his second son, Mr. Frank Green, in 1883.
THE
FIRST EXPERIMENTAL ECONOMISER
| HE first Economiser that was made by Mr. Edward
Green, and which formed the experimental basis of his
subsequent designs, is shown in the illustrations on
page 8. It consisted of a circular group of 30 cast-iron tubes,
4ins. in diameter by gft. in length, connected at the top and
bottom to hemispherical chambers, the cold feed being introduced
into the lower one, and after rising through the tubes passing off
through a branch at the top to the boiler. At the bottom of the
lower hemispherical chamber a blow-off tap was fixed, while a safety
valve was mounted on the upper one. The vessel was practically
an independent boiler, except that it was entirely filled with water,
while the ratio of heating surface to cubic capacity was much
larger and the range of temperature much less than in an ordinary
steam boiler. These primary distinctive features and dimensions
are, it is interesting to note, maintained even in the most highly-
developed form of the apparatus in use at the present day.
The first experimental trials that were made with this apparatus
led great expectations to be formed of its success. The water on
its passage through the tubes was raised to a considerable tempera-
ture, while steam was formed in such quantities that it was frequently
blown-off from the safety valve ; more important still, a large
saving was found to be effected in the amount of coal required.
The expectations thus naturally raised were not, however, perma-
nently maintained. In a few weeks time it was observed that
GREEN'S ECONOMIZER
the escape of steam from the safety valve became less frequent,
the temperature of the water passing off from the Economiser
gradually lower, while the economy in coal correspondingly dwindled,
in addition to which the draught became seriously impaired.
FIG. I. LONGITUDINAL SECTION OF FIRST EXPERIMENTAL ECONOMISER.
This gradual falling off in efficiency naturally caused some little
disappointment and apprehension as to the value of the apparatus.
Mr. Green, however, was convinced that there must be some reason
for the change, and proceeded to investigate the cause. With
this object the brickwork surrounding the apparatus was taken
down, when the source of the trouble was at once revealed.
FIG. 2. PLAN OF FIRST EXPERIMENTAL ECONOMISER.
GREEN'S ECONOMISER 9
The stack of tubes was choked with soot, which not only effectually
screened them from the action of the heat, but also seriously
blocked up the flue, and thus accounted for the defective draught.
The tubes were cleaned, the soot removed from the flue and the
apparatus re-started, when the good results first noted were again
obtained. The water was raised to a high temperature, steam blew
off at the safety valve, and a large economy was effected in the
coal required for the boiler. As before, however, these good
results were only maintained for a short time, and were followed by
a gradual lowering of efficiency as in the first test. The brickwork
was again taken down, and the apparatus thoroughly cleaned. Flue
doors were then fitted to the chamber, through which shavings were
inserted and fired at intervals in order to burn off the soot which
accumulated on the tubes, its removal being further facilitated by the
explosion at intervals of small charges of gunpowder.
These devices proved partially successful, but they could
scarcely be considered satisfactory or of a character to commend
themselves to practical men. This led Mr. Green to design
some automatic method of preventing the accumulation of soot.
After a little scheming he succeeded in effectively doing this
by means of mechanical scrapers, and there can be little doubt
that the subsequent success of the Economiser as a practical
apparatus was largely due to the mechanical method of removing
the soot first planned by him. The idea it may be here stated, was
solely and wholly his, and his claims to the originality of this
or indeed the whole invention have never been disputed. After a
series of trials with this first experimental apparatus Mr. Green
proceeded to protect his several designs by means of letters patent,
which were granted to him on December loth 1845. Patent No.
10,986.
THE DEVELOPMENT
OF
GREEN'S ECONOMISER
THE FIRST ECONOMISER PATENT
>S Patent No. 10,986, in the year 1845, is practically the
foundation upon which all subsequent Economiser
improvements are more or less based, it may be
of interest to reproduce the statement of claim, as well as the
drawing by which it was illustrated, showing the application of
the Economiser to a range of wagon boilers. The following is
a copy of the specification : —
" I, the said Edward Green, do hereby declare
that the nature of my invention and improve-
Patent No. 10,986, . .
ments, and the manner in which the same is to
1845
be performed, is particularly described and
ascertained in and by this instrument in writing. My invention consists
of a new combination or arrangement for the purpose of collecting and
applying to useful purposes the residual heat of the air or gases
passing from the flues of steam boilers, or other boilers and furnaces,
or of either, after such heated air or gases have in ordinary cases ceased
to act with useful effect, and are permitted to make their escape and be
GREEN 'S ECONOMISER
ii
wasted. This combination or arrangement consists, first, of an apparatus
being a series of separate pipes, tubes, or chambers, hereinafter called
pipes, placed vertically, connected at the ends by pipes, or by the cisterns
hereinafter described, through which vertical pipes, water or other liquids
are caused to rise slowly and gradually upward, while at the same time
the heated air and gases passing, or having passed from the flue or flues of
boilers or furnaces, are made to circulate transversely through the spaces
or compartments between and around the pipes, and to remain sufficiently
FIG. 3. LONGITUDINAL SECTION OF GREEN'S FIRST PATENTED ECONOMISER.
long in contact with them to impart to the water or other bequest
contained in and passing through the pipes so much of the surplus or
ordinarily wasted heat as may be required for the occasion. By this
arrangement of the pipes the gravitation of the water and liquid con-
tained therein is made to aid the conduction of the heat from the
heated air and gases in contact with them, the portions of the water or
liquid in contact with the pipes continually ascending as they become
heated, and other and colder portions succeeding, whilst at the same
time any particles of steam that may be generated during the ascent
escape upward not only without impeding the general flow of the water
or liquids, but even assisting the action of the upward current.
12 GREEN'S ECONOMISED
" Secondly, of an apparatus of cisterns placed at the bottom of the
vertical pipes, into which the water or liquid to be heated flows and
with which the whole of the pipes communicate, and of a corresponding
number of cisterns at the top of the pipes, with which also they
FIG. 4. PLAN OF GREEN'S FIRST PATENTED ECONOMISER.
communicate, and which upper cisterns form a reservoir of the heated
water or liquid from whence it may be conveyed to feed the boilers of
steam engines, or for application to any other useful purpose or
manufacture.
" The bottom cisterns are so constructed as to collect any impurities
or ingredients that may be mechanically suspended in the water or
GREEN'S ECONOMISER
a
liquids, and to admit of their being discharged at pleasure by a cock or
plug at the bottom, and the upper cisterns are furnished with movable
lids for ready access to the pipes, thereby enabling the crust or deposit
which necessarily forms in the inner surfaces to be cleaned off or
removed when required
which crust or deposit,
if suffered to accumu-
late, would considerably
impair the absorbing and
conducting power of the
pipes, and thus occasion
the loss of much heat
and corresponding waste
of fuel. By these several
arrangements of the
pipes and of the cisterns,
and the manner of
passing the heated air
or gases through the
spaces and compartments
between and around
them, the hottest portion
of the gases impinging
on the pipes nearest the
fire, and the colder on
those more remote, a
B!
fl
a
flow of water through
the pipes is caused pro-
portionate to the heat
applied, being quicker FIG" 5- OVATION OF SCRAPERS IN FIRST ECONOMISER.
at the hotter part and slower at the colder part of the apparatus,
thus permitting the flow of water from the lower to the upper cisterns
through each pipe to adjust itself to the quantity of heat received
GREEN'S ECONOMISER
by that particular pipe, and thereby equally to abstract the surplus heat
from the heated air or gases. The arrangement has also the further
advantage that the upper and hottest portions of the air or gases
flowing through the
spaces between and
around the pipes
are brought into
contact with the
upper and hottest
portion of the water
or liquid flowing
through the pipes
and the colder with
the colder portion
in the lower parts,
thus abstracting the
heat in the most
effective manner.
" Thirdly, of an
apparatus of Scra-
pers attached to a
frame and made to
encircle the pipes,
which are moved
upwards and down-
wards with a con- FIG. 6. PLAN OF SCRAPERS IN FIRST ECONOMISER.
tinuous and alternating motion, so as to keep the pipes continually
free from any deposit of soot, thus permitting always the full action
of the heated air and gases, which otherwise would be soon impaired
or destroyed ; these Scrapers are balanced by chains connecting
them and passing over pulleys, and they may be worked either in
connection with the engine, if there be one, and by a self-acting
arrangement of suitable pulleys and gear made to alternate three or
GREEN'S ECONOMISER 15
four times an hour, or where no engine is attached, they may be moved
by hand, as occasion may require."
The arrangement of Economiser described in this specifi-
cation, and which is illustrated on pages 11-14, practically embodies
the leading features of nearly all subsequent designs of this apparatus,
including the movable covers in order to obtain access to the
interior of the tubes : the use of automatic scrapers : and also the
arrangement of the flow of water and flow of the gases, so as to
secure as far as possible a maximum and uniform temperature
difference.
On reference to the drawings it will be seen that the
Economiser for each boiler consisted of 60 vertical tubes, in two sets
of 30 each, connected to a large bottom cistern or box, the tubes
being arranged in 1 2 staggered rows of five each, with a transverse
connecting pipe for the hot water at the top of each pair of rows.
The large cisterns at the bottom of the Economiser were designed
with a view to collecting any sediment or impurity in the feed-
water, which was blown off periodically as required.
The arrangement of scrapers which were used will be readily
comprehended on a reference to the enlarged drawings, Figs. 5 and 6,
showing this portion of the apparatus. There were, it will be
observed, two frames to the set of 60 tubes, each frame containing
30 scrapers, so that one set exactly balanced the other, the two
being connected by chains passing over pulleys, whereby the
apparatus could receive an alternating motion by hand or machinery
as desired.
The scrapers in this first arrangement consisted of two plain
hoops which embraced the tubes at a little distance apart, and thus
formed a circular slide. These proved fairly efficient for removing
1 6 GREEN'S ECONOMIZER
the soot when first fixed, but in the course of time, as the hoops
became enlarged by wear, they were apt to lose their efficiency,
and instead of scraping the tubes clean, to slide over the layers of
soot and smooth them down into a thin, hard, non-conducting cake.
With a view to remedy this defect, which several years' experience
made manifest, the inventor next devoted his attention to improving
the design of scrapers, with the results shown in pages 17 to 21.
E Green and This patent, taken out by Messrs. Green in
E. Green, Jr. 1858, appears to treat principally of agitators
Patent No. 877, . . r .
to prevent incrustation, and also of internal water
1850.
tubes. The following were the salient points : —
" This invention has reference to and consists of improvements
upon three former inventions, for which letters patent were granted
to Edward Green on December loth 1845, December loth 1853,
and September I3th 1856, respectively. In the boiler or furnace
flues, through which the heat from the furnace escapes, we place a
series of pipes, chambers, or passages, resembling in their general
features those described in the specifications of the former patents
mentioned. Within these pipes we place either solid blocks of metal,
earthenware, or other suitable substance or hollow pipes, which may be
filled with water, leaving an annular space for the passage of steam
between the outer pipes and the inner blocks or pipes .... The
object of placing water-pipes within the outer pipes is the same,
together with that of imparting heat to the water contained in them,
which water may be used for feeding the boiler or for other purposes,
or may even pass off from the apparatus in the form of steam ....
And having now described the nature of the said invention, and in
what manner the same is to be performed, we declare that we do not
confine the use of our improved apparatuses to the heating of steam
and water, as the same are intended to be employed for heating
air and all other fluids, to the heating of which they may be applicable,
and we claim : Firstly — placing water or other pipes, chambers, or
passages in the flues of furnaces, and furnishing the same with internal
blocks . . . Secondly — placing water or other pipes, chambers, or
passages within steam pipes, chambers, or passages, and these again in
the flues of furnaces essentially as hereinbefore described."
GREEN'S ECONOMISER
SCRAPERS FOR ECONOMISER TUBES
E. Green ^n the specification of Patent No. 2,142,
Patent No. 2,142, 1856, Mr. Edward Green proposed a number of
1856 various designs for scrapers, all more or less
improvements on the type that had up to this date been adopted.
The one, however, which
proved most satisfactory in
practice, and may be said to
have formed the lines on which
subsequent development took
place, is shown in the accom-
panying illustrations, Fig. 7.
The scraper instead of being
made in a complete ring as
previously, was constructed in
two halves, which were hinged
on to pins carried by the
cross-bars of the frames. The
Scrapers had sharp cutting
edges, and while the tendency
of the motion was to cause the
scrapers to clasp the tube and
thus keep it clean, they were
made with a little play so as
to allow them to open slightly FIG" 7' FIRST SECT'°*AL SCRAPER-
if need be, and thus accommodate any accidental inequalities
existing on the outside of the tube.
i8
GREEN'S ECONOMISER
E. Green ^ nas been already pointed out that the
Patent No. 099, efficiency of an Economiser very largely depends
1870 upon maintaining the exterior of the tubes in
clean condition and free from soot or other non-conducting coating,
so as to enable the hot gases passing over the outer surface of the
tubes to give up their heat as rapidly and freely as possible to the
FIG. 8. SECTIONAL SCRAPEUS WITH BALL HINGE.
water within them. To this end considerable attention and thought
have been devoted to the scraping part of the apparatus, and it was
with a view to render this more efficient for the purpose that the
arrangements embodied in Patent No. 999, granted to Mr. E. Green
in 1870, were designed.
GREEN'S ECONOMISER 19
On comparing these designs with those which were previously
proposed it will be evident that they constituted a great improve-
ment. The main object of the invention was to so shape
the scrapers and the parts connected with them as to permit
FIG. 9. PLAN OF SCRAPER.
FIG. IO. SECTION OF SCRAPER.
them to conform to the sides of the tubes under all conditions
without fear of sticking or gagging, an occurrence which
sometimes gave rise to trouble and annoyance. In the improve-
ments under consideration the method proposed to overcome the
difficulty was briefly to construct the scrapers in three or four
sections, each section being pivotted upon an inclined surface or
upon the edge of a lug or projection on the lifting bar or frame.
20
GREEN'S ECONOMISER
Each section was thus free to slide down the incline and keep
its face or scraping edge against the tube. The supporting pivots
being placed a little below the centre of the scraper caused it
naturally to incline towards the tube, and thus clasp the surface of
the tube more effectively in its upward
traverse. With a view to embrace the
complete circle of the tube the circum-
ferential abutments at the top and bottom
were placed a little out of line vertically
so as to break joint.
The action of the scrapers and the
various improvements referred to will be
readily comprehended from the accom-
panying sketches taken from the patent
specification, Fig. 10 being a detailed view
of the scraper, while Fig. 8 shows
elevations of two types of scraper in
position on the tubes, and Fig. 9 a plan
showing the disposition of the scrapers
with respect to the carrying frame.
FIG. II. SCRAPERS WITH
CUTTING TEETH.
Sir E. Green Patent No. 13,804, 1886, by Sir E. Green,
Patent No. 13,804, embodied some further suggestions for the
1886 improvement of the efficiency of the scrapers for
Economiser tubes. The proposal consisted in arranging a number
of diagonal blades or teeth in the portion of the scraper clasping the
tubes, as shown in Fig. n. A variety of designs are shown in
the specification, all substantially embodying the same principle, but
only one or two examples are here illustrated.
GREEN ' S E CONOMISER
21
Sir E. Green Patent No. 23,900, 1892, relates to a further
Patent No. 23,900, improvement by Sir Edward Green, respect-
J8p2 ing scrapers for Economiser tubes. These
are shown in the accompanying sketch, Fig. 12. It will be
observed that each circular scraper is composed of three segments,
and each segment at its junction with the
other two is scarphed or bevelled. This
bevelling is not the same in each case,
but is so arranged that the three segments
can be readily dropped into the carrying
frame by simply placing them in a certain
order, and just as easily removed when
occasion requires, although in conjunction
they practically interlock each other.
Each segment is fitted with a lug, having
an inclined face on its underside, so that
in descending the scraper slides down
the tube by the pressure of its own weight.
On the upward stroke, however, the
wedge-action of the lugs, combined with
the adjustable arrangement of the seg-
ments, causes the scraper to clasp the
tube tightly, and, by means of the circular
cutting edges at the top and bottom, to
thoroughly scrape the surface.
FIG. 12. SECTIONAL INTER-
LOCKING SCRAPER
22 GREEN'S ECONOMISER
DRIVING AND REVERSING GEAR FOR SCRAPERS
E. Green ^n 1866 several important improvements were
Patent No. 2,184, effected in the driving and reversing gear for
1866 the scrapers, and these were embodied in Patent
No. 2,184, granted to Mr. E. Green. The principal features of the
invention consisted in the employment of a single reversing action
FIG. 13. ELEVATION OF SCRAPER REVERSING GEAR
FIG 14. PLAN OF SCRAPER REVERSING GEAR.
for several pulleys, as well as a reciprocating motion deduced from a
continuous positive movement of the gearing. This combination is
coupled with facilities for altering the length of traverse, and a method
GREEN'S ECONOMISER 23
of securing the wheels upon the shafts and transmitting the motion so
as to avoid straining the parts when the clutch box is getting into gear.
The method by which the several improvements were effected
will be best realised by a reference to the accompanying illus-
trations, Figs. 13, 14, and 15 taken from the Patent Specification.
Fig. 14 is a plan of the arrangement, i.i. being the worm wheels
to which the chain wheels, k.k., operating the scrapers, are
attached. One of the wheels, i., by means of the pinion and
FIG. 15. END VIEW OF SCRAPER REVERSING GEAR.
worm, p.q., in conjunction with the wheels, r. and s., operates the
bell crank lever, u., which in its turn acts on the knock-over lever
and weight, w., Fig. 15. By adjusting the stop, t., in the circular
slot it will be evident that the motion of the scraper chains,
24
GREEN'S ECONOMISED
Fig. 13, can be reversed
at any desired point, also
since the chain wheels,
k.k., are secured to the
driving wheels, i.i., by
means of studs, m., any '_-_
particular set of scrapers
may be disconnected by
simply slackening the stud,
without interfering with
the working of the others.
FIG. l6. END VIEW OF QUICK REVERSING GEAR.
Sir E. Green With a view to render the reversing motion in
Patent No. 7,623, connection with Economiser Scrapers more
*887 quick and positive in its action, Sir E. Green,
in Patent No. 7,623, 1887, proposed to supplement the action
FIG. 17. PLAN OF QUICK REVERSING GEAR.
GREEN'S ECONOMIZER 25
of the ordinary reversing arrangement that has already been des-
cribed, by equipping the clutch lever with a weight-race. In this
race a live ball, roller, or sliding weight, by rapidly changing the
position of the centre of gravity of the lever when on the dead centre,
secured the more prompt and effective action of the reversing
mechanism. The manner in which it is proposed to apply this
arrangement will be readily understood by reference to the accom-
panying sketches, Figs. 16 and 17, in which R. represents the live
or sliding weight.
Sir E. Green Patent No. 23,901, 1892, by Sir E. Green,
Patent No. 23,901, has reference to improvements in the mitre
1892 gear wheels used in the reversing mechanism
connected with the scrapers, the said improvement consisting in
the use of shrouded wheels to prevent the rattling and shock some-
times produced when the reversing mechanism is put into operation.
\
LIDS AND SEATINGS FOR ECONOMISER TUBES
E. Green The rise in steam pressures which followed
Patent No. 3,794, the introduction of the compound and triple
1882 expansion engine involved, as a consequence,
several modifications in the design of Economiser details. Prominent
amongst these was the method of securing the lids of the sight holes
in the top boxes, affording access to the interior of the tubes. Up to
this date these lids were of the external type, held in position by
an internal crossbar and screw. For very high pressures, however, it
was desirable there should be no risk of the lids beine blown off in
o
the event of the crossbar being weakened by corrosion or straining.
26
GREEN'S ECONOMIZER
With a view to obviate any risk of this kind the type of lid
shown in the accompanying sketch, Fig. 18, and which is taken
from the drawing accompanying Patent No. 3,794, 1882, was
designed. The cover was of the internal type, and made
slightly conical, with the small end of the cone looking upwards,
so that the tendency of the pressure in the interior of the
Economiser was to force the cover more tightly in its place. The
cover, it will be noticed, was provided on its upper side with a
hole for the reception of a Lewis
bolt, to which a screw could be
attached, and by means of the
movable external cross bar or
saddle the lids drawn in place.
The conical joint faces were in
practice made plain, and it was
found this was adequate for
tightness, though the patent was
made to embrace a screw-thread
on the conical facing of the lid,
having the same pitch as the
draw-screw in case this was found
to be desirable.
INTERNAL CONICAL
E Green Patent No. 2,623, 1884, had reference to a
Patent No. 2,623, method proposed by Mr. E. Green for sealing
1884 the holes in Economiser caps in cases where
these caps or lids were of the external type and held in position
by a central bolt and internal cross-bar. The novelty of the invention
consisted in the use of a conical soft metal collar to fill the space
between the bolt and the hole in the cover. This collar was expanded
GREEN'S ECONOMIZER
27
by the pressure of the nut in tightening up, and thus made a steam and
water-tight joint. The device was not adopted to any extent, but
FIG. 19. SOFT METAL COLLAR BEFORE TIGHTENING BOLT.
FIG. 2O. SOFT METAL COLLAR AFTER TIGHTENING BOLT.
is described here in order to render the record of the various patents
complete. See Figs. 19 and 20.
28
GREEN 'S ECONO MISER
Sir E. Green In tne Year l889, Patent
Patent No. 3,867, No. 3,867, Sir E. Green
1889 described a proposed im-
provement in the form of the bolt head
securing the cap of the Economiser tube to the
internal cross-bar. It was found in some cases
that the head of the bolt under the cross-bar
was seriously eaten away by the action of
corrosive water, and the holding power of the
bolt thereby seriously impaired. With a view
to prevent this it was proposed to make the
shank of the bolt of tapering triangular form,
so as to dispense with the ordinary head, as shown in Fig. 21.
FIG. 21. TRIANGULAR
BOLT FOR
ECONOMISER LID.
Sir E. Green
Patent No. 9,546,
Patent N°- 9,546,
1892, relates to certain
proposed improve-
ments by Sir E. Green, in the con-
struction of the caps or lids for the
top boxes of Economisers. The design
proposed is shown in Fig. 22, which
gives a longitudinal section through the
top box and also a plan of the lid. The
lid, it will be observed, is made oval for
its insertion through the hole in the
box, which is fitted with a depending lip
or narrow-joint surface against which
the face of the cover bears.
FIG. 22. OVAL INTERNAL LID.
GREEN'S ECONOMISER
29
Sir E Green ^n 1892, another patent, No. 18,674, was granted
Patent No. 18,674, to Sir E. Green, for two designs of conical
1892 Hds. These are shown in Figs. 23 and 24. In
Fig. 23 the cover is circular, with its larger diameter slightly less
than the smaller diameter of the conical hole in the box so as to
permit of its insertion, the joint being made by means of a
FIG. 23. INTERNAL LID WITH
COPPER JOINT RING.
FIG. 24. INTERNAL OVAL LID WITH
CONICAL JOINT FACE.
copper or other soft metal ring of circular section, which
would permit of being sprung through the hole and placed in
position over the conical lid. This could then be tightened up, the
pressure on the packing ring when the lid was drawn up into
place making the joint. In the design shown in Fig. 24 the lid is
oval, so that it can be made of the same size as the hole in the top
box, and the joint formed metal to metal without the aid of a
packing ring, as shown in the previous design.
30 GREEN'S ECONOMISER
SECTIONAL TOP AND BOTTOM BOXES
E. Green Patent No. 8,178, 1885, granted to Mr. E. Green,
Patent No. 8,178, had reference to a method of arranging the
J885 Economiser tubes in such a way that one or
more of the tubes were separated from the others by a partition or
FIG. 25. ECONOMISER WITH FEED DOWN FLOW.
diaphragm in the upper box, so that the cold feed which entered
from the main situated at the top of the Economiser was made
GREEN'S ECONOMISER
3>
to pass in a downward stream on one side of the partition
into the bottom boxes, from whence it ascended in a series of
upward currents into the top boxes. Another portion of the
Patent had reference to the construction of the Economiser, so that
each tube was a separate casting and interchangeable, and thus the
Economiser could be built up, if desired, of any required dimen-
sions. The features of these proposed modifications of design are
shown in Figs. 25 and 26. Fig. 25 illustrating the arrangement for
securing the circulation, and Fig. 26 the method of building up the
j
FIG. 26. METHOD OF CONSTRUCTING ECONOMISER OF SEPARATE TUBES.
Economiser in separate tubes. In Fig. 25 the arrows show the
direction of the flow of the hot and cold water. In actual practice
it was seldom found that either of the modifications of design here
shown were necessary, but they are given as illustrating the
attention that has been devoted to small details with a view to
render the apparatus as perfect as care and the teachings of
experience can possibly make it.
32 GREEN'S ECONOMISER
ECONOMISER BOTTOM BOXES
Sir E. Green 1° 1887, Patent No. 2,989, Sir E. Green
Patent No. 2,989, proposed certain modifications in the con-
J887 struction of the bottom boxes with a view
to the more efficient removal of any scale or sediment that might
collect therein. The proposal consisted of the use of a mechanical
rotating tool for loosening the sediment, combined with certain
FIG. 27. KCOXOMISER FITTED WITH AGITATOR FOR REMOVAL OF MUD AND SCALE.
modifications in the shape of the bottom box and mud
chamber for the more easy removal of any accumulation by means
of the blow-out. Various methods were proposed to effect this
object. Fig. 27 shows one arrangement in which a mechanical
worm or agitator was fitted in the bottom box, and revolved by-
hand, with a view to remove the accumulated mud or scale when
the blow-out tap was opened.
ECONOMISER WITH FEED DOWNFLOW
Sir E. Green The accompanying arrangements, Fig. 28,
Patent No. 8,651, have been designed by Sir E. Green to prevent
I8p5 the vapour in the waste gases condensing on the
outside of the Economiser tubes. This condensation or "sweatino- "
•vv-v ,/...;.;,' ' ' ' ' ' ' ', ': ' v
FIG. 28. ECONOMISER WITH FEED UOWNFLOW ARRANGEMENT TO PREVENT "SWEATING" OF THE TUBES
34 GREEN'S ECONOMISER
is most noticeable at the feed inlet end, especially at the lower
part where the tubes are connected to the bottom boxes, and is
objectionable as it combines with the sulphurous fumes given off
by the coal, and forms an acid which rapidly eats away the tubes.
In the arrangement shown, the feed water instead of being
delivered to the whole of the bottom boxes of the Economiser
and flowing upwards in an uniform direction throughout the
whole of the tubes, is delivered in the first instance to the top
boxes of a number of sections which are isolated from the rest.
This portion of the Economiser may consist of 4, 6, 8, or any
number of sections as is found desirable. The upper end of each
of the tubes in these sections is fitted with a small nozzle so as to
restrict the area, and insure an approximately even distribution
and downflow of the feed. By this means the inflowing current
of feed water is raised in temperature before it reaches the bottom
boxes, from whence it flows upwards through the remaining tubes
in the usual way.
In order to further prevent the "sweating," the hot water
outlet pipe of the Economiser and the suction side of the feed pump
should be connected with a small pipe (say fin. in diameter), to
take off the chill whenever the temperature of the feed is 90° F.
or less.
OTHER
ECONOMISER INVENTIONS
HE great economy that followed the application of
Messrs. Greens' Economisers or Feed-water Heaters to
steam boilers, led not only to its rapid and exten-
sive adoption by steam users, but, as might naturally be
expected brought a number of rival inventors into the field.
The careful manner, however, in which every detail of the
apparatus had been considered, left little room for improve-
ment. Some of the rival designs proposed were utterly
impracticable, and were never submitted to the test of actual
work. Others appeared to possess good features, but when
tested gave rise to so much trouble and difficulty, or developed
such dangerous defects, that they were discarded after a short
period of working. Space forbids enumeration of all the
varied arrangements that have at different times been proposed,
and their description would scarcely serve any useful purpose,
though a brief reference to some of the more important ones may
perhaps prove of interest.
The problem of keeping the surface of the Economiser tubes
free from soot or other non-conducting coating was, as
already pointed out, one to which Messrs. Green's attention was
drawn, and to which considerable efforts were devoted at a very
early stage in the Economisers' history, and subsequent experience
36 OTHER ECONOMIZER INVENTIONS
under a variety of conditions has proved that the question of soot
removal can only be effectively dealt with by means of mechanical
scrapers clasping the outside of the tubes.
Lees 1° 1864, however, a Mr. J. W. Lees took out
Patent No. 1,325, a patent, No. 1,325, in which he proposed to
1864 remove the soot by means of a series of fine
steam jets, so arranged as to act as a kind of brush. The
t
FIG. 29. LEES' REVOLVING STEAM BRUSH.
OTHER ECONOMIZER INVENTIONS 37
apparatus consisted of a steam pipe, which passed through the
centre of the Economiser stack, and revolved in glands at each end.
At intervals along the pipe hollow radial arms were fixed, having
sniall perforations throughout their length. By turning a hand-
wheel, fixed at one end of the central pipe, the radial arms
described circles in the spaces between each sheet of tubes, and
thus when steam was turned on the small jets played over the area
of the circle described by the revolving arms. The general
arrangement of this apparatus will be perceived on a reference to
Fig. 29.
The method of cleansing the tubes, proposed by Mr. Lees,
though apparently simple and promising well on paper, did not
prove efficient in practice. It was found that the coating of soot
became gradually thicker and of a hard adherent character, which
slowly but surely prevented the passage of heat, and after a com-
paratively short time rendered the Economiser almost worthless.
In connection with this apparatus it may be noted in passing,
that the tubes were arranged horizontally instead of vertically,
while they were so connected as to cause the water to flow in one
continuous stream from the inlet to the outlet, instead of slowly
rising through the whole series of tubes, as in Messrs. Green's modern
arrangement. This idea, however, of continuous circulation was
not novel even thirty years ago, and the arrangement of the
Economiser so as to insure the water traversing either each tube,
or section of tubes in turn, was provided for in one of Green's
earlier specifications.
Although the "continuous circulation" system may appear very
attractive on paper, actual working has proved it on several
occasions to be open to serious objection and even danger, while
careful tests have shown that the continuous circulation Economiser
38 OTHER ECONOMIZER INVENTIONS
does not possess any advantage on the score of economy. The
matter, however, will be found more fully discussed on page 7 1 .
Whitehead As an illustration of the manner in which the
Patent No. 503, same ideas are re-invented, it may be stated that,
1866 jn the year 1866, a Mr. J. H. Whitehead, in
Patent No. 503, again proposed the use of a steam or compressed
air brush. This was
identical in principle with
the one patented by
Mr. Lees and described
above, the only difference
being that in the present
patent the brush consisted
of a series of pendant pipes
which were traversed along
the spaces between the
Economiser tubes by means
of a rack and pinion with
the aid of a sliding stuffing-
box arrangement.
FIG. 30. SECTION OF TWIBILL's SUPPLEMENTARY HEATER.
Twibill In the year 1866, Mr. Joseph Twibill took out
Patent No. 2,378, a patent, No. 2,378, for improvements in the
1866 construction of supplementary Steam Genera-
tors and Scraping Apparatus. The principal feature in connection
with Mr. Twibill's invention consisted in the position of the supple-
mentary heater relative to the boiler and its connection thereto.
OTHER ECONOMISER INVENTIONS
39
The form of the apparatus proposed varied somewhat with the type
of boiler employed, but the general principle will be realised on a
reference to Figs. 30 and 31, which show its application to a
boiler of the ordinary Lancashire type. The heater consisted of
a stack of tubes, E E, fitted with water-boxes, F F, at the top
and bottom, and placed in the down-take at the back end opposite
the furnace tubes, B B. The water-boxes, F F, were connected
to the boiler by the tubes, D and D D, so that there was a
circulation
continuous
through the supplemen-
tary heater, the water
flowing from the boiler
into the lower box, F,
and thence passing up
through the vertical
tubes, E E, into the upper
box any steam generated
passing through the
tube, D, into the boiler.
This so-called "Feed-
water Heater " was
simply a water-circulating
arrangement. As far as
the temperature of the FIG" 3I" PLAN °F TWIBILL'S SUPPLEMENTARY HEATER.
steam and water within it were concerned the apparatus was
merely an extension of the boiler heating surface.
4o
OTHER ECONOMIZER INVENTIONS
Mannock 1° l867> Patent No. 2,086, Mr. James Mannock
Patent No. 2,086, proposed the arrangement of tube scraper shown
J867 in Fig. 32. The scraper, it will be seen, con-
sisted simply of an annular cup or holder which encircled the tube,
and carried within it two or three loose segments. These, by sliding
FIC. 32. MANNOCK S SCKAI'ER.
FIG. 33. ROBINSON'S SCRAPER.
on the inclined bottom of the cup, were forced to bring their cutting
edges against the outside of the tube and bear against it when
making the up stroke.
Robinson Fig. 33 shows a proposal by Mr. J. Robinson,
Patent No. 679, embodied in Patent No. 679, 1868, for scraping
Z868 the outside of horizontal Economiser tubes.
The scraper consisted of two parts which swivelled on a pin and
clasped the outside of a tube like the legs of a pair of callipers.
This arrangement, it will be obvious, would not permit of application
to an Economiser of ordinary vertical tube construction.
Whitehead Another device for cleaning the soot off the out-
Patent No. 1,197, side of Economiser tubes was proposed, by the
1868 ]y[r Whitehead already referred to, in Patent
No. 1,197, 1868. The contrivance, however, was very crude,
OTHER ECONOMISER INVENTIONS 41
and consisted simply of a series of short curved blades attached
to chains which formed an endless band, and ran over pulleys at the
top and bottom. The operation of these chains caused the blades
to catch against the tubes — which were fixed horizontally — for a
short portion of their circumference as it passed up and down on
each side. A large portion of the surface of the tubes could,
however, not be operated on at all by this device, and it is doubtful
whether the arrangement proposed was ever tried in practice.
Holt & Galloway In Patent No. 2,253, l868> Messrs. C. H.
Patent No. 2,253, Holt and C. J. Galloway show a continuous
J868 circulation Economiser of the form illustrated
in Fig. 34. In this arrangement the principle of "continuous
FIG. 34. HOLT (5r> GALLOWAY'S CONTINUOUS CIRCULATION ECONOMISER.
circulation " was adopted, i.e., the water was made to flow in one
sinuous stream from the inlet to the outlet, the apparatus forming
42 OTHER ECONOMISER INVENTIONS
practically one continuous thoroughfare. The tubes were arranged
vertically and hung pendulous from the top boxes. To ensure
continuous circulation each tube was divided by a vertical
diaphragm extending nearly, but not quite, to the bottom, the water
flowing down one side and up the other, and so on in succession
throughout the entire series of tubes from the inlet to the
outlet.
A number of Economisers of this kind were put into operation,
but the impossibility of locating the position of any block in the
circulation arising from the deposit of sediment or other cause was
found to give rise to serious trouble. Added to this, it was
impossible to empty the Economiser except by boiling off the
water, and in one case where this was attempted, the pressure,
even with the safety valve open, increased to such an extent
in consequence of the peculiar construction of the arrangement
that a disastrous explosion resulted. This called wide attention
to the dangerous character of this type of apparatus, unless
equipped with a number of safety valves, and led to its being
generally discarded.
Needham In tne same year, 1868, a Patent No. 3,358
Patent No. 3,358, was granted to Mr. Richard Needham, for
1868 improvements in Economiser scrapers. The
novelty claimed in this case was the fixing of the movable blades
of the scraper, which were of flat semi-circular shape, in guides,
so that the scrapers were inclined to the axis of the tubes at an
angle of about 45°. The previous use of blades of the form
described is admitted in the Patent Specification, and the only
claim for novelty appears to have been the fixing of them at
an inclination in the manner stated.
OTHER ECONOMISER INVENTIONS
43
Needham A ^ew months later, Mr. Richard Needham, in
Patent No. 3,749, Patent No. 3,749, 1868, described further
1868 designs for improving the operation of scraper
driving and reversing apparatus. One method by which he pro-
posed to operate the gear for working the
scrapers is shown in Fig. 35. This consisted in
placing within the Economiser tube an archime-
dean screw, having a central shaft revolving in a
footstep at the bottom, and passing through a
stuffing box at the top. The idea was, that the
current of water travelling up the tube would act
upon the screw and cause it to revolve, and
that from the motion thus imparted to the shaft,
the scrapers could be operated. The current of
water flowing through an Economiser is so slow,
however, that it is questionable whether any
appreciable motion could be obtained in this way,
and it is doubtful if the design was ever more
than sketched on paper.
A more ingenious and practical proposal,
taken from the same patent, is shown in Fig. 36,
and represents a method of obtaining a reversing motion of
the scrapers from the continuous revolution of a driving shaft.
This shaft had cut upon it two screw threads — one right-
handed, the other left-handed. Into these threads a shuttle,
carried by a short sleeve, engaged, so that when the sleeve
reached each end of the shaft the shuttle was transferred from the
groove in which it was running to that of the opposite hand, and
the sleeve thus carried alternately from end to end of the shaft.
FIG. 35. NEEDHAM S
SCREW SHAFT.
44
OTHER ECONOMISER INVENTIONS
To this sliding sleeve, chains led over pulleys were connected, the
ends being attached to two sets of scrapers which balanced
FIG. 36. NE&DHAM'S REVERSING MOTION FOR SCRAPERS.
each other, and moved up and down as the sleeve travelled to
and fro.
In this same specification Mr. Needham suggested another
improvement, which, however, like many others that have been
proposed from time to time, is much easier to draw on paper
than to carry out in practice. The proposal was that each sheet
of vertical Economiser tubes, along with the top and bottom boxes,
to which they were connected, should be all cast in one piece.
However laudable this method of construction may be for some
reasons, it is to be feared the difficulties of adopting it would prove
insuperable.
OTHER ECONOMIZER INVENTIONS
45
Obach Fig. 37 shows a design which was proposed
Patent No. 728, by Mr. T. Obach, in Patent No. 728, 1869, f°r
1869 securing Economiser tubes to the top and
bottom boxes in such a way as to permit of their easy removal when
necessary. The lower end of each tube was
fitted with lugs on each side. These passed
through a corresponding recess, which admitted
of their access to a helical groove, so that by
partially revolving the tube the spigot end was
forced hard against a flat ring of copper or
other soft metal placed on the joint face of the
bottom box. At the upper end the tube was
turned conical, and a corresponding hole bored
in the top box, while the screw which held the
cover in place was prolonged in the shank so as
to bear against a cross-bar fitted in the upper
end of the tube. The screw thus served the
double purpose of bolting down the cover and
forcing the tube into position. The design
proposed was ingenious, but it would be much
easier to put tubes together in this way when
new than it would be to separate them after
working for a time when the lugs would be
rusted fast in the groove and almost impossible
to release without fracturing the bottom box.
Fig. 38 shows the arrangement of scrapers
which was also covered by this specification.
These were sector-shaped, and worked on a hinge, so that the
scrapers permitted of a certain amount of play when they
encountered any irregularity or obstruction on the face of the tube.
46
OTHER ECONOMISER INVENTIONS
The same patent included a design
of the inventor for operating the reversing
gear of scrapers. This is shown in Fig. 39.
The driving pulley, A, actuates a worm, B,
and thereby gives a constant revolution
to the crank, C, attached to the worm
wheel. By means of a connecting rod, D,
a second crank, E, of larger throw is
operated. This is attached to a toothed
sector, F, which is thus caused to travel
to and fro in the arc of a circle. Through
the medium of a toothed wheel, K, which
is fixed to the shaft carrying the scraper
chain wheels, M, the latter are caused to no. 38. OPACH'S SCRAPER.
alternately revolve in opposite directions, and thus raise or lower
the scraper frames to which they are attached.
FIG. 39. OBACH'S REVERSING MOTION FOR SCRAPKRS.
OTHER ECONOMISER INVENTIONS
47
Bell In 1870, Patent No. 3,365, Mr. Andrew Bell
Patent No. 3,365, proposed to arrange the Economiser tubes in
1870 the form of a series of spirals similar to the one
shown in the accompanying sketch, Fig. 40, instead of in vertical
rows as in Messrs. Green's arrangement. The tubes were kept
clean on the outside by the action of three radial scrapers which
were operated by the
central vertical shaft,
B, and travelled down
the helical tube until
they reached nearly to
the bottom, when, by
means of the reversing
gear the direction of
rotation of the shaft B
was reversed. It is
difficult to see what
advantage could be
reaped by arranging
the tubes spirally, while
such an arrangement
absolutely prohibited
the cleaning of the
tubes internally. This,
apart from other
difficulties, constituted
a fatal objection, and
although the apparatus
was practically tried,
it had an exceedingly
"- . :,.- .
FIG. 40. BELL'S SPIRAL ECONOMISER.
48
OTHER ECONOMISER INVENTIONS
limited application, and the trouble experienced in its working
soon caused it to be abandoned.
Mundy
Patent No. 2,876,
Mr. E. Mundy, in Patent No. 2,876, 1871,
proposed certain improvements in the design of
I8?i scrapers. In this case the scrapers consisted of
two sets of segments encircling the tube and placed one above the
other, the segments being operated by a ring or hoop having a
bevelled edge, so that a pressure could be exerted when the scraper
frame was raised in the usual way.
FIG. 41. ELEVATION OF CALVERT & TAYLOR'S CONTINUOUS CIRCULATION ECONOMISER.
OTHER ECONOMISER INVENTIONS
49
Calvert & Taylor ^n l&72> the principle of continuous circulation
Patent No. 350, was again " invented " and made the subject
1872 matter of Patent No. 350 granted to Messrs.
J. C. Calvert and J. Taylor, of Huddersfield. The arrangement
proposed by them is shown in Figs. 41 and 42. The tubes it will
be seen were vertical, and depended from a series of top boxes in
pairs, each pair being connected at the bottom with a semi-circular
bend, while the top boxes were divided with diagonal partitions, so
KIG. 42. PLAN OF CALVERT
TAYLOR'S CONTINUOUS CIRCULATION ECONOMISER.
that the tubes belonging to each pair were connected to a separate
compartment. These were so arranged that the water was caused
to travel in a continuous stream through the whole series of tubes,
from the inlet to the outlet.
Elson The accompanying illustrations, Figs.43 and 44,
Patent No. 695, show an arrangement of Economiser devised
1872 by Mr. S. Elson, Patent No. 695, 1872. The
apparatus consisted of two rows of tubes, or " bottles " as they were
50 OTHER ECONOMISER INVENTIONS
termed, the lower ends being blanked up and the upper ends of each
row connected to one longitudinal collecting pipe. The water
entered the Economiser through a small tube placed inside the
upper longitudinal one, and from this flowed down a central tube,
which extended nearly to the bottom of each " bottle," the ascending
FIG. 43. ELSON S BOTTLE ECONOMISER.
currents of water being again collected in the upper pipe, and
thence passed to the boiler. The scrapers were of a somewhat
novel design, consisting of revolving strips of wrought-iron, which
were bent helically round the "bottle," and connected to a loose
collar at the bottom and a worm wheel at the top, which was
operated by a central shaft passing between the two rows of
"bottles." See Fig. 44.
A number of these Economisers were put to work, but the
grave defects which attended their working, and which in one or
OTHER ECONOMIZER INVENTIONS
two instances resulted in disastrous explosions, led to the com-
plete abandonment of the type in the course of a few years.
In the case of muddy or dirty water there was no means of
blowing off the Economiser, and the accumulation of dirt and
sediment at the bottom choked the end of the flow-pipe, so that
the water in the "bottle"
became stagnant or idle. In
the event of the upper neck
becoming choked as well, which
it was very liable to do on
account of the narrow water
space, the "bottle" was at once
converted into an hermetically-
sealed vessel, and on the
application of heat explosion
became almost inevitable. The
pendant form of the "bottles,"
coupled with their large
diameter, was also a source of
44-
SPIRAL SCKAPERb
weakness, and in the case of ;
one "bottle" bursting, the
others followed in succession like a row of skittles. Further, from
an economical point of view, the large diameter of the "bottles"
was a defect, since the ratio of heating surface to capacity is less
with large tubes than with small ones.
Lees & Garforth Messrs. R. J. Lees and J. H. Garforth, in Patent
Patent No. 3,324, No. 3,324, 1872, proposed certain improvements
1872 in the form of scrapers as well as in the arrange-
ment of the flow of water through the tubes. The design of scraper
52 OTHER ECONOMISER INVENTIONS
proposed by them is shown in Fig. 45. The scrapers consisted
of flat-bars, running lengthwise of the tube, and attached to iron
rods, which were connected to a revolving plate at the upper end.
These plates were secured to a series of wheels which geared
KIC. 45.
&> GARFORTH S CONTINUOUS CIRCULATION KCO.M >M I
into each other so that the whole of the scrapers in a sheet of
tubes were driven together and operated by a single worm and
wheel. It will be observed that the tubes were scraped in a circum-
ferential and not in a longitudinal direction, as in nearly all the
other arrangements that had been proposed.
In this apparatus the tubes were cast in pairs, united with a
U-shaped bend at the bottom, and connected with one another
OTHER ECONOMIZER INVENTIONS
53
by elbows at the top, in such a way as to cause continuous
circulation. In the provisional specification this was claimed as
FIG. 46. ELEVATION OF TWIBILL's CIRCULAR ECONOMISER.
FIG. 47. PLAN OF TWIBILLS CIRCULAR ECONOMISER.
part of the invention, but in the complete patent the idea of
novelty on behalf of the circulation of the water was repudiated
and no claim made in respect of it.
54
OTHER ECONOMISER INVENTIONS
Twibill 1° t^ie year 1873, Mr. J- Twibill took out a
Patent No. 3,791, Patent, No. 3,791, for an Economiser of the
1873 form shown in the illustrations, Figs. 46 and 47.
The main feature of Mr. Twibill's invention consisted in arranging
the Economiser tubes in one or more circles attached to a central
water chamber, the advantages claimed on behalf of the
arrangement being that greater facility was afforded for dealing
with filtrated or precipitated sediment.
Mason & Alcock ^n l%74> tne principle of continuous circulation
Patent No. 1,436, was once more brought forth in Patent No. 1,436,
!874 granted to Messrs. S. Mason and M. Alcock.
The arrangement proposed is shown in Fig. 48. The tubes in this
FIG. 48. MASON &* ALCOCK'S CONTINUOUS CIRCULATION ECONOMISER.
OTHER ECONOMIZER INVENTIONS
55
design were arranged horizontally, and fixed in two tiers, one above
the other, which ran transversely across the flue, the scrapers
FIG. 49. ELEVATION OF PKESTWICH &= PIMBLEY's SPLIT TUBE ECONOMISER.
FIG. 50. PLAN OF PRESTWICH Cr PIMBLEY'S SPLIT TUBE ECONOMISER.
being operated by means of a sliding rack and pinion, in conjunction
with an ordinary reversing gear.
56 OTHER ECONOMIZER INVENTIONS
Prestwich and Figs. 49 anc^ 5° represent an idea embodied in
Pimbley Patent No. 4,235, 1874, by J. Prestwich and
Patent No. 4,235, J. Pimbley, with the object of increasing the
74 surface of Economiser tubes and diminishing
the volume of water. It was proposed to effect this by con-
structing the body of the vertical tube in two segments, as shown
in the plan, Fig. 50, the space between the segments permitting
of the introduction of a scraper so that soot could be removed
both from the convex and concave sides. In this, as well as in
other similar devices that have been proposed for diminishing
the volume of water in the Economiser, inventors appear to
forget that by reducing the volume of water in the apparatus
its rate of flow is necessarily accelerated, so that, although the
heating surface is relatively greater, the length of time the
water remains in contact with it is correspondingly curtailed,
and what is gained in one direction is lost in another. In
the construction, as sketched in this Patent, it will be observed
that there is no arrangement for insuring the circulation of water
through the tubes, which consisted of a series of bottles of dead
water with blind ends at the bottom. The feed inlet, as well as
the delivery outlet, was situated at the top, and the efficiency of an
apparatus so constructed would prove very small.
Bell In Patent No. 639, 1880, granted to Mr.
Patent No. 639, Andrew Bell, several so-called novelties are
J88o described and are here illustrated in Fig. 51.
The first claim made is for the coupling together of the Economiser
tubes by a series of elbows at the top and bottom, so that each trans-
verse row is in the form of agridiron, while each row is connected to the
succeeding one in such away that the water is made to flow in one
coniinuous stream throughout the whole length of the Economiser
OTHER ECONOMISER INVENTIONS
57
fro
the inlet to the outlet. This is the Continuous Circulation
Economiser again. A second claim
made by Mr. Bell is that the
water passes through the Econo-
miser in a direction contrary to
the flow of the heated gases. This
was adopted in Green's earliest
patents. A third claim was for
the inclination of the separate rows
of tubes in opposite directions,
with the object of causing the
gases flowing through the spaces
in one row to impinge on the tubes
in the next, but as the preceding
pages show, this idea had been
repeatedly exploited.
FIG. 51. BELL'S CONTINUOUS CIRCULATION
ECONOMISED
Sykes The next invention proposed for the improve-
Patent No. 1,746, ment of the Economiser was one by Mr. T.
Z882 Sykes, in 1882, Patent No. 1,746. Theinvention
consisted in placing three or four tubes together so as to form a group,
as shown in Fig. 5 2, these groups being connected to longitudinal
or transverse boxes at top and bottom by a tapered spigot in the usual
way. The object of this invention, as stated in the specification, was
" to obtain an increased amount of heating surface and a more rapid
circulation of the water." It is difficult to see how this end could be
attained by the means proposed. The grouping of the tubes together
would certainly tend to diminish the heating surface rather than
increase it, and the circulation could not be in any way effected as
OTHER ECONOMIZER INVENTIONS
FIG. 52. SYKES' GROUPED TUBE ECONOMISER.
compared with an Economiser of ordinary construction, provided
the volume of water remained the same.
Lowcock & Taylor 1° Patent No. 3,306, 1882, Messrs. A. Lowcock
Patent No. 3.306, and J. Taylor suggested certain improvements in
1882 tne mechanism for raising and lowering the
scraper frames of Economisers, as well as the use of sheet-iron blades
beneath the scrapers for passing between the transverse bottom
boxes and preventing any accumulation of soot choking the
thoroughfare. As this patent refers rather to matters of a detailed
character, it scarcely calls for further description.
OTHER ECONOMISER INVENTIONS
Perkins & Scott In 1882,
Patent No. 3,5o2, Messrs. J.
1882 G. Perkins
and J. Scott took out a Patent,
No. 3,502, referring principally
to the construction of scrapers
and of internal tapered access
lids for the top boxes of Econo-
misers, thereby dispensing
with the use of bolts and
cross-bars. The scrapers were
of what is known as crab-jaw
construction, and consisted of
circular segments, embracing a
portion of the tube, and con-
nected by levers to a lug or
hinge on the scraper frame,
the action of which caused
the scrapers to exert pressure FIG" 53' PERKINS * SCOTT'S CRAB'JAW SCRAPERS'
at the upper or lower ends according as they were raised or lowered.
Lowcock & Sykes The illustrations given in Figs. 54 and 55 show
Patent No. 2,875, certain arrangements for blowing-out Econo-
J885 misers, which were proposed in Patent No. 2,875,
1885, by Mr. A. Lowcock and Mr. T. Sykes. The claim for
novelty consisted in constructing the bottom box in such a
way as to cause it to slope towards the blow-out pipe, either
as shown in Fig. 54 where the blow-out pipe runs longi-
tudinally through the soot chamber, or as shown in Fig. 55
where the bottom box is divided into two compartments by a
6o
OTHER ECONOMISER INVENTIONS
sloping diaphragm extending nearly throughout its length, the
blow-off pipe being connected to the lower compartment. By this
means it was contended that any mud or dirt accumulating in the
bottom box could be more efficiently cleared away on opening the
blow-out tap.
FIGS. 54 &" 55. LOWCOCK & SYKES' BLOW-OUT ARRANGEMENTS.
Bell
Patent No. 8,020,
In 1885, Mr. A. Bell, in Patent No. 8,020,
described an arrangement of Economiser shown
in the accompanying sketches, Figs. 56 and 57,
with a view to obtaining a continuous circulation of water, while
OTHER ECONOMISER INVENTIONS
61
ni Ji in ii
m
7
FIGS. 560^57. PLAN AND ELEVATION OF BELL'S CONTINUOUS CIRCULATION ECONOMISER.
62
OTHER ECONOMISER INVENTIONS
the tubes were arranged in staggered rows, with the object, it was
claimed, of causing the heated gases to impinge more directly upon
their surfaces than was possible when they were arranged in line
behind each other.
It is scarcely necessary to discuss the details which Mr. Bell
proposed to insure continuous circulation, as a reference to the
abstracts already given will show that the idea was in no sense
new, and as regards the arrangement of the tubes in staggered
rows for securing a more direct impingement of heated gases upon
them, it may be pointed out that this arrangement was shown in
Green's first patent, see Fig. 4, page 12. The reasoning, however,
as to the superiority of this plan is to a great extent fallacious. The
absorption of heat by Econo-
miser tubes is determined not
by the impingement of the
gases upon them, but by the
difference in temperature be-
tween the gases outside and
the water inside. In other
words, the amount of heat taken
up by each tube is influenced
by this temperature difference
rather than by the position of
the tube with respect to the
gases flowing past it.
FIG. 58. HA\VKINS TOP AND BOTTOM BOXES.
Hawkins ^n Patent No. 14, 141, 1887, Mr. G. C. Hawkins
Patent No. 14,141, proposed to do away with the longitudinal branch
J887 tubes, used for connecting the top and bottom
boxes together, in the manner shown in Figs. 58 and 59. In this
OTHER ECONOMISER INVENTIONS 63
arrangement the top and bottom boxes were to be provided with
facings around a series of holes, which permitted of them
communicating with each other, the end boxes of the series being
FIG. 59. HAWKINS' TOP AND BOTTOM BOXES.
fitted with an elbow and flange for connecting to the feed inlet,
feed outlet, or blow-out pipe. For the purpose of drawing the
various sections together and of resisting the tendency to be forced
apart by the internal pressure, bolt stays were provided as shown
in Fig. 59. Any advantages that can possibly accrue from such an
arrangement as this are more than counterbalanced by the practical
difficulty which would be experienced in making the joints.
64
OTHER ECONOMISED INDENTIONS
Lowcock & Sykes Judging from the number of patents that have at
Patent No. 16,114, one time or another been taken out with a view
1887 to promoting the flow of water in Economisers,
it would appear that those inventors who have taken up the subject
entirely overlook the fact that in the Economiser, as constructed by
Messrs. Green's, the circulation in each tube is regulated by the
amount of heat it receives. If one tube receives more heat than
another the result is a greater amount of convection and a greater
inflow of cold water, the circulation throughout the Economiser
thus adjusting itself in a natural manner. Where there is
most heat there is the most rapid circulation, and where there is
least heat there is the slowest circulation. The distribution of
heat and circulation go hand in hand and mutually accommodate
each other. From this it will be evident that designs to make
the water flow at a constant rate through every tube in an
FIG. 60. LOWCOCK &* SYKES' BOTTOM BOXES
Economiser with a view to promote economy, are futile. Hence
such a proposal as the one shown in Fig. 60, which was the subject
of Patent No. 16,114 granted to Messrs. A. Lowcock and T. Sykes
in the year 1887, is of doubtful value. The patent consisted
simply in making the bottom boxes of a taper-shape with a varying
diameter proportional to the number of pipes to be fed.
OTHER ECONOMISER INVENTIONS
Twibill Mr. Joseph Twibill, in 1888, Patent No. 7,354,
Patent No. 7,354, suggested an arrangement of Economiser with
1888 internal circulating tubes, as shown in Fig. 61.
Each top box of the Economiser was divided into two compart-
ments by a horizontal diaphragm, extending from end to end, and
forming a tube plate for fixing the internal circulating tubes. The
FIG. 61. TWIBII.L'S INTERNAL CIRCULATING TUBE ECONOMISER.
bottom box was also fitted with a tube plate, but this was only of
bar-shape, having a slight enlargement at the parts where the
circulating tubes were fixed, and did not divide the bottom box into
two separate compartments as in the case of the upper one. The
circulation of the water is fairly indicated by the direction of the
arrows in the accompanying sketches. From the feed inlet the
water passed into the upper compartment of the top box and
thence downward through the inner circulating tubes to the bottom
66
OTHER ECONOMISER INVENTIONS
box from which it flowed upwards through the series of annular
spaces between the inner circulating tubes and the Economiser
tubes proper into the lower compartment of the top box, and
then away to the outlet. It is difficult to see what practical
advantage could accrue from this arrangement, as the heating
surface is in no way increased, and the internal cleaning of an
Economiser of this kind would present very serious difficulties.
Sykes The accompanying illustration, Fig. 62, shows
Patent No. 4,778, the construction of caps or lids of Economiser
1890 tubes which forms the basis of Patent No. 4,778,
granted to Mr. T. Sykes in 1890. The cap is provided with a
circular rib of angular section,
which fits into a corresponding
groove or seating turned in the
face of the top box. This, it is
claimed, permits of the joints
being broken with less risk of
injury to the top box. The
joint is made either by means
of lead putty in the usual way,
or by using a ring or lining of
copper or other suitable metal
laid in the bottom of the circular groove referred to.
FIG. 62. SYKES' ECONOMISER LID.
Burpee 1° Patent No. 21,243, 1890, taken out by G. H.
Patent No. 21,243, Burpee, several claims for novelty in the con-
I^90 struction of Economisers are made. These
relate principally to the use of spigot joints instead of flanges for con-
necting the bottom and top boxes to the branch pipes, and also to the
OTHER ECONOMISER INVENTIONS 67
method of forming the taper of the spigot ends of the vertical tubes.
The novelty in respect to this latter claim consisted in making the
taper of the ends of the Economiser tubes point downwards in each
case, with the object of more easily withdrawing and renewing a tube
in the event of repair. The idea is one, however, that presents
greater advantages on paper than are found to exist in practice.
Sykes A few months after Mr. Burpee's patent, just
Patent No. 6,439, described, was granted, another patent, No.
^91 6,439, 1891, was taken out by Mr. T. Sykes
having an identically similar object, namely, the formation of the
tapers on the ends of the Economiser tubes so that the tapers
pointed downwards in each case.
Topham ^n the Year 1892 Mr. E. Topham
Patent No. 13,438, took out a patent, No. 13,438, for
1892 connecting two vertical sheets of
tubes to a common top and bottom box, the vertical
tubes being so arranged that those in one row were
opposite the spaces of the next row, with the object,
FIG. 63. TOPHAM'S DOUBLE TUBE BOXES.
68 OTHER ECONOMISER INVENTIONS
it was claimed, of rendering the heating surface of the tubes
more efficient by causing the stream of gases to impinge more
directly upon them. Whatever advantage may be supposed to
accrue from this, and it is very doubtful whether, as already
pointed out on page 62, any possible economy does result, the
proposal to arrange the tubes in staggered rows instead of in
parallel lines was at all events not novel. The arrangement of
the tubes in this way was shown in Mr. Edward Green's first
patent, see Fig. 4, page 1 2.
Sankey Patent No. 21,918, 1892, refers to a design of
Patent No. 21,918, feed-water heater proposed by Mr. W. H.
l&92 Sankey. The arrangement described in the
specification consists of a series of tubes connected to flat chambers
at the top and bottom, so arranged as to cause a continuous flow
through the whole series from the inlet to the outlet, and
refers more particularly to heating by exhaust steam, though the
claim is also made for its use in the main flue of a boiler to utilize
the waste heat of the gases. Before it could be adopted, however,
in such a position, the design as it is described would require very
extensive modification, and is merely referred to here as an
illustration of the extent to which the application of the principle of
continuous circulation to the Economiser has been made the subject
of letters patent.
Calvert From the references that have been already
Patent No. 4,775, made, it will be apparent that the principle of
'SpS continuous circulation in Economisers has
often been the subject of investigation by inventors of
Economisers, and it might be thought that the capacity for
OTHER ECONOMIZER INVENTIONS 69
taking out patents in this direction would have become exhausted.
Another patent for an Economiser of this type was granted to
Mr. J. G. Calvert in 1893, Patent No. 4,775. As regards principle,
this apparatus is identical with that of previous ones, the tubes
being vertical and connected so as to cause the water to flow
alternately up and down the various sheets of tubes in succession
from the inlet to the outlet. A number of minor arrangements of
the taps and valves are covered by the patent. These appear,
however, to give rise to great complication.
Sykes This patent refers to a method of securing the
Patent No. 5,401, lids of the holes in the top boxes. The lids are
J894 constructed in the form of screwed plugs, with
a faced seating or bearing surface fitting into correspondingly
screwed nipples formed on the upper side of the top boxes. It
would no doubt be an easy and simple matter to secure the lids and
make the joints in this way ; but after they have been in position
for some time and exposed to the action of heat and water, the
threads of the lid and nipple, it is to be feared, would become rusted
so fast together as to render it next to impossible to separate them.
It may further be pointed out that the construction of screw lids
was covered by Mr. E. Green's Patent, No. 3,794, in 1882.
See page 25.
Sykes ^n ^94, ^r- ^ • Sykes, in Patent No. 13,409,
Patent No. 13,409, proposed to interfere partially with the thorough-
1894 fare of the vertical tubes of Economisers by
inserting in each tube one of smaller diameter, either blind or
partially blind at its upper end, and projecting into the bottom box.
By this means it is claimed the water in its passage through the
70 OTHER ECONOMIZER INVENTIONS
Economiser will be compelled to traverse the annular space between
the inner and outer tubes, and thus become heated " more rapidly and
to a higher temperature." The misapprehension that underlies
several of the inventions of this class that have been proposed has
been already so fully referred to that it scarcely calls for further
reference here. Inventors appear to forget when drawing up such
designs, that if the volume of water flowing through the Economiser
is reduced, the average length of time occupied in its passage is
correspondingly shortened, and thus any increase in the efficiency
of the heating surface is neutralised by the diminished length of
time the water remains in contact with it. The gain in one direction
is balanced by the loss in another. We would further add that
this patent appears similar to No. 877, taken out by Mr. E. Green
and Mr. E. Green, Junior, in 1858. See page 16.
Knight & Thode This joint patent of C. A. Knight and G. W.
Patent No. 24,320, Thode refers to a feed-water heater consisting
1894 of several groups of horizontal or inclined tubes,
connected at the ends to vertical headers, these being divided in
such a way that the water circulating through them is caused to
flow in succession through the several sections of the apparatus.
It is difficult in this arrangement to find any features of novelty.
The use of horizontal or slightly-inclined tubes, as will be seen on
reference to previous sketches, is in no sense new, any more than
the principle of continuous circulation. In the arrangement shown
in the specification the tubes are unprovided with scrapers ; and
there can be little doubt such an apparatus as the one sketched
would, in practice, prove very inefficient in consequence of the
deposit of soot.
ECONOMISERS
HAVING
CONTINUOUS CIRCULATION
N tracing the history and development of the
Economiser in the preceding pages, it will have
been observed that the system of forcing the water
through one long continuous tube instead of allowing
it to flow simultaneously through a number of tubes, as in
Messrs. Green's system, has been the subject of many patents. It
has, in fact, been designed over and over again.* Inventors appear
to have been impressed with the idea that a continuous flow, by
causing the water to pass through one long tortuous length of tube
instead of a number of short ones, must result in its being heated
to a greater extent, forgetting that such an arrangement necessitates
the water travelling at a correspondingly higher velocity, and that
for a given rate of feed the time occupied in passing through
the Economiser is precisely the same whether the apparatus be
arranged on the continuous system or in accordance with
Messrs. Green's arrangement, and, further, that the amount of
heating is determined by the length of time the water is in contact
with the gases, not the velocity with which the water travels.
* For inventions referring to continuous circttlation see following
Lees' Patent, No. 1,325, 1864, page 36
Holt and Gallo-jaay's Patent, No. 2,253, 1868, page 41
Calvert and Taylor's Patent, No. 350, 1 872, page 49
Lees and Garforth's Patent, No. 3,324, 1872, page 51
Mason and Alcock's Patent, No. 1,436, 1874, page 54
Belt's Patent, No. 639, 1880, page 56
BelCs Patent, No. 8,020, 1885, page 60
Sankey's Patent, No. 21,918, 1892, pag
Culvert's Patent, No. 4,775, 1893, page 68
Knight & Thode's Patent, No. 24,320, 1894, page 70
CONTINUOUS ECONOMIZERS
This consideration alone is sufficient to show the fallacy of
the views underlying the designs of Circulating Economisers,
while it may be pointed out that in such arrangements the
water encounters greater resistance in the Economiser in
consequence of its higher velocity, and therefore calls for
more pumping power. Further, unless special provision is made,
there is in some designs of Circulating Economisers a risk of
the pressure, under certain conditions, becoming excessive.
In fact, one of the most
disastrous Economiser
explosions on record was
due to the apparatus
being arranged on the
continuous circulating
principle.
FIG. 64. CALVERT'S ECONOMISER; METHOD
OF CONNECTING SECTIONS.
FIG. 65. BLOW-OUT ARRANGEMENT OF
CALVERT'S ECONOMISER.
During the last year or two strenuous efforts have been made
to revive the circulating type of Economiser. With a view to
avoid the risk of excessive pressure which existed in early arrange-
ments, this latest type of the apparatus has been equipped with
CONTINUOUS ECONOMIZERS ?$
safety valves on each section, while the blow-out arrangement has
necessitated the use of a back-pressure valve, for each bottom box,
the valve being either of ball type or the simple flap form shown
in the accompanying illustrations, Figs. 64 and 65.
These various valves, it will be evident, render the apparatus
complicated, and, from an economical point of view, do not give the
slightest advantage. As extraordinary claims, however, have been
made by the Patentees of this apparatus on the score of economy,
it was thought desirable to submit the two types to a series of
thoroughly impartial and independent tests by engineering observers
whose character and professional standing should be beyond
question, and with this object the Chief Engineers of the four
leading Boiler Insurance and Inspecting Companies in the country
were requested to conduct the tests.
The results obtained at these trials were unanimous and con-
clusive. They fully confirmed previous experience, and proved that,
as far as economy is concerned, the Circulating Economiser is in
no degree superior to the ordinary design, but, on the other hand is
liable to cause trouble from its complicated arrangement.
In support of this, the following extracts from the Reports of
the Chief Engineers who made the tests, are quoted : —
J. F. L. CROSSLAND, M. Inst. C.E., the Chief Engineer of the
Boiler Insurance and Steam Power Company, Limited, Manchester,
for instance, at the conclusion of his report, dated September 7th
1894, states : —
" The test shows that no advantage is obtained by the Calvert
pattern, while the additional pressure due to the resistance in the
pipes of the Economiser under trial, and the objectional liability to
trouble arising from the stoppage of the scouring valves, constitute
important disadvantages inseparable from this Economiser."
74 CONTINUOUS ECONOMISERS
MICHAEL LONGRIDGE, M. Inst. C.E., Chief Engineer of the
Engine, Boiler, and Employers' Liability Insurance Company,
Limited, Manchester, in his report, dated September nth, remarks
on the tests as follows : —
" They prove conclusively that under the conditions under which
the experiments were made, which are the conditions under which
Economisers are usually worked, no appreciable advantage is derived
from Circulation, whether the Economiser be Green's or Calvert's,
while the liability to short circuiting, which appears to exist in the
Patent Circulation Economiser, is a decided disadvantage."
LAVINGTON E. FLETCHER, M. Inst. C.E., Chief Engineer of the
Manchester Steam Users Association states : —
"The figures obtained during the tests made September I4th
1894, do not show any practical advantage in the continuous current
system over the ordinary system."
EDWARD G. HILLER, M. I. Mech. E., Chief Engineer of the
National Boiler Insurance Company, Limited, Manchester, remarks
as follows with regard to three separate tests that he conducted on
June ist, June 8th, and September i3th 1894 : —
" Taking the three tests into consideration, a little variation of
the results in detail is to be observed, but generally the deviations
do not exceed those which might be expected had the same
apparatus been tested on each occasion, and considered as a whole
they do not show any material economical difference between Green's
Ordinary Economiser, Green's Circulating Economiser, and Calvert's
Economiser."
CIRCULATORS versus ECONOMISERS
HE success of Green's Economiser, as already re-
j marked, has at various times given rise to various
] imitations, and with a view to securing as inventors
have fondly imagined greater efficiency, designs have been put
forward which indicate a complete misconception of the distinctive
feature of Mr. Edward Green's first invention. This is most
clearly shown in the types of so-called " feed-water heaters "
which are placed in the down-take at the back end of the boiler
with a view to obtain the advantage of high temperature, and
which is illustrated in Mr. Twibill's Patent, No, 2,378, 1866,
described on page 38.
In this design the "heater" is coupled to the boiler, both
at the feed and outlet end, and is really a circulator, and as far as
the economy of the boiler is concerned, is merely an extension of
the boiler-heating surface. As inventors do not appear to grasp the
fallacy which underlies this type of heater, and as numerous designs
embodying the same principle have at various times been patented,
it may be of service to steam users to point out why such designs,
as compared with the Green's Economiser, must from the nature
of the case be foredoomed to failure.
It is obvious that in any boiler the temperature of the waste
gases cannot be reduced below that of the water and steam. Any
attempt to attain this end by extending the heating surface would
result in the boiler heating the gases instead of the gases heating
the boiler, and thus prove a source of loss. As a matter of fact, it
is found in practice that the temperature of the gases can only be
;6 CIRCULA TORS
brought down to within about 100° F. or 150° F. of this point. Thus
in a boiler working say at a pressure of 100 pounds, corresponding
to a temperature of about 340° F., the waste gases must necessarily
pass away at a temperature of 450° to 500° F., and provided, therefore,
the heating surface of the boiler is sufficient to bring the tempera-
ture of the gases down to this point, no possible advantage can
accrue from a mere extension of the capacity and heating surface
of the boiler itself. Now, in the majority of cases, the proportions
of the boiler are sufficient to effect this, and therefore the addition
of a " Circulator" of the type shown can produce no economy what-
ever. To call such an apparatus an " Economiser" in the sense
in which the word is now generally understood — i.e., as a separate
and distinct vessel for heating the feed-water with waste heat — is
misleading.
Compared with such an apparatus, the "Fuel Economiser"
embodies an entirely distinct principle. It is, in fact, a separate
boiler working within lower limits than are available with the
ordinary steam generator, and this it was that constituted the dis-
tinctive feature of Mr. Edward Green's first invention. To
illustrate the matter in another way : It may be stated that, with
an ordinary steam boiler and chimney draught, it is only possible to
lower the temperature of the gases from that of the furnace, about
i, 600° F., down to that of the flue outlet, say 500° F. As already
pointed out, this latter temperature cannot, as a rule, be reduced to
any serious extent by means of the boiler alone. With the aid of
Green's Economiser, however, this terminal temperature becomes
available as the source of heat for raising the feed-water from about
90° F. to something like 300° F., the rise being accompanied by a
fall in the temperature of the gases, which without the aid of some
such apparatus would be impossible.
GREEN'S EARLY TUBULAR BOILERS
HE great strength, combined with the large extent
of heating surface and the facility for easy handling
which became available by the introduction of the
tubular sectional element in the construction of
Green's Economisers, naturally suggested its application for steam
generating purposes in other directions besides that for which it
was first employed. Mr. Green, in fact, appears to have
FIG, 66. TUBULAR HIGH-PRESSURE BOILER, CONSTRUCTED BY MR, E. GREEN ABOUT
78 GREEN'S EARLY BOILERS
realised at a very early date that economy in the application of
steam was to be sought in two directions, namely : — The extension
of the boiler-heating surface, and the use of cylindrical vessels of
small diameter with a view to the use of higher pressures. Some
of the designs suggested and executed by him bear such a striking
resemblance in many respects to the forms of sectional boiler in
KIG. 67. TUBULAR HIGH-PRESSURE BOILER, CONSTRUCTED BY MR. E. GREEN ABOUT 1850.
successful use at the present day, that it may not be out of place to
refer briefly to them here in view of the claims for novelty that are
sometimes put forward in connection with boilers of this class.
Figs. 66 and 67, for example, give cross sections of two
designs of boilers of the tubular class which were proposed and
constructed by him about the year 1850. The general features
of the design are in many respects admirable, and as a vessel
GREEN'S EARLY BOILERS
79
Fir,. 68. MR. E. GREEN'S MULTITUBULAR EGG-ENDED BOILER, 1853.
for the generation of steam at high pressures, a striking advance
on most of the ideas that had up
to that time been proposed. The
boiler, it will be seen, consisted of
an upper drum connected to two
lower longitudinal water cylinders
by one or two rows of tubes,
which formed inclined walls of
heating surface on which the fire
played.
FIG. 69. CROSS SECTION OF BOILER
SHOWN IN FIG. 68.
E. Green Illustrations, Nos. 68 to 70, represent two
Patent No. 2,882, of several designs embodied by Mr. Green
1853 in Patent No. 2,882, 1853, his object being to
increase the heating surface in the plain externally-fired boilers,
which were the current type at that period. The idea is so clearly
set forth in the illustrations shown that little description is necessary.
The boiler, instead of being cylindrical, was made somewhat oval in
8o
GREEN'S EARLY BOILERS
section, with flat sides forming tube plates, having several horizontal
rows of tubes. These afforded a very considerable extension of the
heating surface, and very much increased the efficiency of the
plain, cylindrical boiler. The tubes, as will be seen from Fig. 68,
were arranged in several groups, the heated gases passing through
these in succession, from side to side, until the back end was
FIG. 7O. PAIR OF MR. E. GREEN'S EGG-ENDED MULTITUBUI.AR BOILERS.
reached, when they were discharged into the chimney. Fig. 70 is
a slight modification of the design, showing a pair of this type of
boiler working side by side in conjunction.
In 1 86 1, the first Mr. Edward Green, in con-
junction with his son, then Mr., now Sir Edward
Green, took out a patent, No. 2,671, for a
variety of applications of the sectional principle
of construction, not only to the design of steam
boilers, but also to condensers and superheaters. Space will not
permit of more than a brief reference to these. It may be stated,
however, that many of the designs shown in this early specification
E. Green
and
E. Green, Jr.
Patent No. 2,671,
1861
GREEN'S EARLY BOILERS
Si
— and to which those interested in the subject may be referred
for fuller information — anticipate in principle many of the improve-
ments that have been adopted in these kinds of apparatus during
recent years.
Figs. 71 and 72 for instance show the plan and elevation of a
Sectional Tubular Boiler, with tubes of tapered polygonal or
fluted section. The fire was arranged in an external brick furnace,
o©oo©@©®.
~ ' •• *•• --••.-••'.
FIG. 71. GREEN'S SECTIONAL BOILER WITH EXTERNAL FURNACE, 1861.
FIG. 72. PLAN OF BOILER SHOWN IN FIG. 71.
82
GREEN'S EARLY BOILERS
whilst vertical pipes were coupled at the top to a collecting steam
drum. In some of the other designs proposed, the furnace was
surrounded with a water jacket or with walls of vertical tubes in
close contact with each other, resembling in this respect the design
of several of the Water Tube Boilers adopted in current practice.
FIG. 73. GREEN'S SECTIONAL FURNACE, 1861.
Fig. 73 shows another proposed arrangement in which the
furnace was circular, and consisted of hollow rings built up on a
common axis, so that when a number were placed together the
furnace assumed the form of a tube. This design for the furnace
was proposed with a view to prevent the loss of heat by radiation
that is apt to attend the working of an external brickwork furnace,
and which sometimes militates against its efficiency. The arrange-
ment shown in the sketch illustrates, of course, only the furnace
portion of the boiler exposed to the direct radiation of the fire,
the remaining portion of the heating surface, as well as of the
GREEN'S EARLY BOILERS
84
GREEN'S EARLY BOILERS
FIG. 75. CROSS SECTION OF
BOILER SHOWN IN FIG. 74.
steam-collecting drum, permitting of being arranged, either as
shown in Fig. 71 or in accordance with one of the many other
designs described in the Specification.
Fig. 74 shows a sectional boiler
consisting practically of a long furnace
tube built up of a series of rings, such as
have been described, and which was
made by Messrs. Green in order to
supply steam for driving their own
works in the year 1860. The boiler was
practically of the Cornish type, and was
set in brickwork with external flues, so as
to utilise the heat of the gases and
prevent radiation. The rings of which
the furnace tube was composed were
connected with a water-pipe at the top, above which was placed
the steam-collecting pipe, as shown in Fig. 75. As a sectional
boiler for high pressures the design possesses many excellent
features, and was much superior to the majority of designs
that had up to that time been proposed. The boiler proved
very satisfactory in practice, and did duty at Messrs. Green's
works for many years.
Fig. 76 shows the manner in which a number of Economisers
were connected together and fitted with a steam drum, so as to form
a steam boiler fired with the flames from an external furnace.
This arrangement was first adopted to meet the wants of a sugar
works at Greenock, about the year 1863, and was subsequently
applied in a number of other cases with very satisfactory results.
Figs. 77 and 78 show two other designs of sectional tubular
boilers constructed by Messrs. Green during the years 1862 and
GREEN'S EARLY BOILERS
86
GREEN'S EARLY BOILERS
GREEN'S EARLY BOILERS
GREEN'S EARLY BOILERS
— tl
1
3
^—L^
jj
*-,
GREEN'S EARLY BOILERS
89
1863. In the design shown in Fig. 78 the furnace was constructed
in sections somewhat similar to those shown in Figs. 73 and 74,
except that the sections were of horse-shoe shape, as shown in
ig. 79, instead of being circular.
This permitted of the grate being
lowered if required, so as to afford
a large furnace capacity, without
diminishing the grate area. This
is a point of considerable advantage
in the burning of wood fuel, and
a number of boilers of this type
were sent out to Russia and
worked for upwards of 20 years
with very good results.
Fig. 80 shows another com-
pact design of tubular boiler, of
which a number were constructed
about the year 1862. The sides
and back as well as the top and bottom of the furnace
were composed of water tubes, thus securing the economic
advantages of internal firing. The boiler was one which
afforded a large amount of heating surface in a relatively
small space, and with good water worked with very satis-
factory results. For the purpose of facilitating the removal
of any sediment which was contained in the water, and
which naturally settled in the lower row of tubes, the
latter were fitted with mechanical agitators. By means
of a handle these could be revolved and the accumu-
lated mud periodically discharged through the blow-out
tap.
FIG. 79. SECTION THROUGH FURNACE
OF BOILER SHOWN IN FIG. 78.
GREEN'S EARLY BOILERS
GREEN'S EARLY BOILERS 91
E. Green Patent No. 1,416, 1870, refers to another form
Patent No. 1,416, of Sectional Boiler proposed and constructed
1870 by Mr. Green. The boiler, which is shown in
Fig. 8 1, consisted of a series of horizontal drums lying side by side
in contact with each other, so that the lower half of their circum-
ference formed the roof of the furnace. Each of these drums
was connected with a row of tapered vertical tubes, the upper parts
of which formed the steam space, as shown in the cross section.
The flames, after passing along the underside of the lower
drums, were deflected towards the front by means of a baffle
plate through the nest of vertical tapered tubes, and thence
returned to the chimney, as shown by the arrows. The
tubes in each row were connected together in the steam space
by short necks, while the whole of the rows were coupled to a
common main steam-pipe. The tapered form of tubes afforded easy
access between the rows to a man for the purpose of inspection,
while their upper ends were fitted with removable covers, so that
the interiors could be examined when desired.
GREEN'S EARLY SUPERHEATERS
S the influence of steam superheating in pro-
moting economy in the working of steam
engines is a question in which interest has
been somewhat revived during recent years,
it may not be out of place to note that the subject was one to
which Messrs. Green devoted considerable attention at a com-
FIG. 82. GREEN'S SUPERHEATER, 1858.
GREEN'S EARLY SUPERHEATERS 93
paratively early period. The accompanying illustration, Fig. 82
shows a superheating arrangement which was erected by them in
the year 1858. The superheater, it will be seen, was constructed
on the same sectional principle as the Economiser, and in fact placed
in the same chamber, being situated however at the inlet end, and
thus exposed to the highest temperature of the waste gases, which
were afterwards used for heating the feed water in the tubes of
the Economiser proper. A number of superheaters of this kind
were erected, and where circumstances were favourable proved
satisfactory.
The adoption of superheating, however, forty years ago was
attended with a number of practical difficulties that frequently
outweighed its theoretical advantages. The high temperature of
the steam gave rise to considerable trouble in connection with the
lubrication of the cylinder walls and valve faces, as well as the
packing of the glands. The former were frequently scored and
abraded, and the latter rapidly burnt out. Since then great
advances have been made in the manufacture of special lubricants
for surfaces working at high temperatures as well as in the con-
struction of metallic packings for pistons and glands. By these
means the troubles which were formerly experienced in connection
with the use of highly-superheated steam, and which eventually led
to its disuse, have been largely overcome. It will be seen, however,
that the superheating of steam is not the novelty that is sometimes
supposed, and that in connection with its first introduction the firm
of Messrs. Green played a not unimportant part.
GREEN'S MODERN ECONOMISER
HE accompanying illustrations represent Messrs. Green's
improved arrangement of Economiser as developed by
the process of evolution sketched in the preceding pages,
and which may be said to fairly embody all the good features
suggested by special study combined
with fifty years' practical experience
in its manufacture and working.
The apparatus, as will be seen
on reference to the sketches on
the opposite page, consists of a set of
cast-iron tubes about four inches in
diameter by nine feet in length,
made in sections of various widths to
suit the convenience of the boiler
plant, and set vertically in parallel
rows so as to afford facility for
inspection. These sections are con-
nected together by transverse pipes
or boxes at the top and bottom,
which are in turn connected to
FIG. 85. CROSS SECTION THROUGH
ECONOMISER CHAMBER.
branch pipes running lengthwise
on opposite sides, and situated outside the brickwork which
encloses the arrangement.
GREEN'S MODERN ECONOMIZER
95
FIG. 83. LONGITUDINAL SECTION THROUGH ECONOMISER CHAMBER.
FIG. 84. PLAN OF ECONOMISER CHAMBER SHOWING PASSAGE FOR INSPECTION.
96 GREEN'S MODERN ECONOMISER
The apparatus is fixed in a bye-pass situated in the main flue
between the boilers and the chimney, and fitted with suitable
dampers so that it may be at once isolated for the purpose of
inspection or repair without in any way interfering with the
working of the boilers.
Along one side of the Economiser a passage is generally left
wide enough to admit of a man for the purpose of inspection, while
underneath the bottom boxes is a chamber for the collection of the
soot removed by the scrapers, provided with suitable doors to
admit of periodical cleaning.
The feed- water is forced into the Economiser through the
bottom branch pipe at the end of the apparatus where the gases
make their exit. From this branch pipe it has free access to all
the bottom boxes, and rising slowly through the whole nest of tubes
makes its escape from the top branch pipe at the opposite
end of the Economiser where the gases enter. Thus the water
inlet end of the Economiser is the gas outlet end, and the water
outlet the gas inlet end.
At the end of the bottom branch pipe opposite to the feed
inlet a blow-off valve is fixed, so that any accumulated mud or
sediment which collects in the bottom boxes can be blown out as
required. At the end of the top branch pipe opposite to the outlet
valve a safety valve is fixed to prevent any excessive accumulation
of pressure.
Each tube is provided with a scraper, which is made to travel
continuously up and down the tube at a slow rate of speed, so as to
keep the external surface free from any non-conducting coating of
soot, and thus maintain its efficiency. These scrapers are grouped
together, so that those on two adjoining sections of tubes form a
single set, which is balanced by the set on the next two sections of
GREEN'S MODERN ECONOMISER
97
tubes. The scrapers are thus exactly counterpoised, and very little
power is required for their operation.
The driving of the scrapers is effected by means of a shaft
running the length of the Economiser, and carrying worms at
intervals which gear into toothed wheels attached to the chain
FIG. 86. GREEN'S QUICK REVERSING MOTION FOR SCRAPERS.
pulleys, over which the scrapers are suspended. At one end of
the Economiser is an automatic arrangement by which the motion
of the scrapers is reversed as they alternately reach the top and
bottom end of the tubes. See Fig. 86. The motive-power for
98
GREEN'S MODERN ECONOMISER
GREEN'S MODERN ECONOMIZER
99
the driving may be supplied either by a belt from some convenient
shaft or by a small separate engine, as shown in the illustration
on page 98.
The tubes of the Economiser are made from a special combina-
tion of best Scotch pig and
Hematite, cast vertically in
dry sand moulds, and are
guaranteed to be of equal
thickness as well as sound
and free from blow holes
throughout. Every tube used
is tested before being sent out
of the works by hydraulic
pressure to 650 pounds on
the square inch.
Equal care is taken in
the construction of the top
and bottom boxes. The
joints of the tubes and
boxes are all conical, turned
and bored metal to metal,
and forced together by
powerful hydraulic machinery specially designed for the purpose.
The lids and holes to each tube are also turned and bored
conical to template, so that the joint can be made without the
intervention of any hemp or red lead. See Figs. 88 and 89.
The scrapers are carefully designed so as to readily
accommodate themselves to the tube, and have a thin cutting
edge so as to prevent any accumulation of soot. See Fig. 12,
page 21.
EXTERNAL LID FOR ORDINARY PRESSURES.
100
GREEN'S MODERN ECONOMIZER
All parts of the Economiser are made strictly to template on the
interchangeable system, while duplicate standard castings of every
part are always in stock, so that any portion can be renewed at a
moment's notice.
FIG. 89. INTERNAL LID FOR HIGH PRESSURES
(TRIPLE AND QUADRUPLE EXPANSION.)
It is of interest to note that the apparatus can be installed
without any stoppage of the works or interference with the working
of the boilers ; and in the case of a tube failing, an event which
rarely occurs, it can be replaced in an hour or so by unscrewing one
nut and lifting one lid. See explanatory illustration, Fig. 90.
GREEN'S MODERN ECONOMISER 101
FIG. 90. METHOD OF WITHDRAWING DAMAGED TUBE BY MEANS OF LEWIS WEDGE AND
DRAW BOLT.
1. Tube as ordinarily fixed. 3. Draw-bolt and Lewis Wedge in position.
2. Tube Slit at top to permit of being 4. New Tube in position.
sprung through hole. 5. Stop Ferrules for isolating damaged tube
SIZE AND EFFICIENCY
OF
GREEN'S MODERN ECONOMISER
HE economy effected by the adoption of a Green's
Economiser varies from 10 to 20 per cent, of the total
fuel consumed, according to the temperature of the
escaping gases from the boiler.
The temperature of the gases is reduced, on an average, from
650° F. on the boiler side of the Economiser to 350° F. on the
chimney side, while the temperature of the feed-water is increased,
on an average, from 1 80° to 200° F.
It is not desirable under ordinary circumstances to cool the
gases below 350° F., as this temperature is generally required to
maintain the natural draught in the chimney. If the temperature
of the gases on leaving the boiler does not exceed 400° F. an
Economiser is not as a rule advisable.
The feed-water should be supplied to the Economiser at as
high a temperature as possible, in order to prevent the watery
vapour, in the products of combustion, condensing on the outside of
the cold tubes. Such "sweating" or condensation is apt to cause
external corrosion. If the feed-water is under 90° F. it is a good
plan to connect a f-inch pipe from the hot water outlet of the
Economiser to the suction pipe of the pump, in order to take off
the chill and prevent the risk of " sweating."
GREEN'S MODERN ECONOMISER 103
The percentage of gain resulting from the increase of tempera-
ture of the feed-water may be found by the following formula : —
Gain per cent. =
Where H = Total heat of Steam at Boiler Pressure reckoned
from o° Fahrenheit.
„ t = Temperature of Feed-water in degrees
Fahrenheit, before heating.
., T = Temperature of Feed-water in degrees
Fahrenheit, after heating.
The following clear widths should be allowed inside the
Economiser Chamber for various sizes of Green's Economiser : —
ft. in.
Economiser 4 tubes in width 3—4 inside chamber.
6 „ 4—8 „
8 „ „ 6—0 „
10 „ „ 7—4 „
NOTE. — The above widths are exclusive of that necessary when a
passage is allowed down the side of the Economiser for the
purpose of inspection, and for which an additional 9 inches
should be added to the dimensions given above.
In fixing on the size of an Economiser for a given boiler plant,
four tubes should be allowed for each ton of coal consumed per
week. Thus, if 20 tons of coal are consumed per week, the
Economiser should contain not less than 20 x 4 = 80 tubes. If the
coal consumption is not readily ascertainable, another convenient
rule is to allow one tube for every three Indicated Horse- Power.
Thus, 300 I.H.-P. would require about 300-^-3 = 100 tubes.
On account of the scraper arrangements the number of tubes
in an Economiser must be increased or diminished by not less than
four sections. Thus, if the Economiser is four tubes in width, its
size requires to be altered 4x4=16 tubes at a time. If it is six
104
GREEN'S MODERN ECONOMIZER
tubes in width the alteration in size is 6 x 4 = 24 tubes at a time ;
and so on.
If the number of tubes in an Economiser exceeds 96, it is
better to divide the Economiser into one or more groups, with
FIG. 91. METHOD OF FLUSHING BOTTOM BOXES WITH THE AID OF ACCESS LIDS.
GREEN'S MODERN ECONOMISED
105
space between each group to permit of inspection, the top and
bottom branch pipes of the several groups being connected
together by suitable bends, so as to allow freedom for expansion
and contraction. See Figs. 83 and 84, page 95.
FIG. 92. ACCESS LIDS FOR TOP BOXES TO PERMIT OF FLUSHING AS SHOWN IN FIG. 91.
Each Economiser tube holds on an average about 5 gallons
of water, including top and bottom boxes. Hence the number of
tubes x 6 gives the capacity of the Economiser in gallons. Thus
the capacity of an Economiser with 96 tubes = 96 x 6 = 576
gallons.
GREEN'S ECONOMISER
DIRECTIONS FOR WORKING
When raising- steam the reserve flue damper
Raising Steam
should be kept open until the Engines are started.
The Outlet Valve between the Economiser and
Connections to
Boilers tne boilers should not be closed when raising
steam, or during the night, or at meal times.
Regulation and Eeed the boilers constantly, keep the boiler feed
Temperature valves open and regulate the feed, as far as
practicable, by the inlet valve to the Economiser.
The Economiser must not be fed with water at a lower temperature
than 90° F.
Pump Relief A Relief Valve, weighted slightly in excess of
the working pressure of the boilers, should be
placed on the feed pipe, between the pump and the Economiser.
Regulate the draught of the boiler by the main
Cp^ damper at the outlet end of the Economiser,
and not by the boiler dampers. The latter
should only be used in case a boiler is laid off.
Prevent any cold air leaking into the main flues ;
Leakage of Air 3
make all crevices in the brickwork air-tight.
Test the Blow-out Valve at the bottom of the
Blow-out Valve
Economiser daily.
Test the Safety Valve on the Economiser daily.
On large Economisers, or those working at high
pressures, an additional direct loaded spring valve may be applied.
DIRECTIONS FOR WORKING 107
All Valves, and especially the safety valve,
Inspection of
Valves should be carefully examined periodically, and
all waste water delivered so that it will not drain
into the soot pit, flues, or cleaning-out space.
Keep the Scrapers constantly at work when heat
Scrapers and
G rin 1S Passm£ through the hconomiser. The cross
shaft carrying clutch box should run at 55 revo-
lutions per minute. If the scrapers stick, remove the set screw
connecting chain pulley and worm wheel, and work the scrapers up
and down by hand until they run freely. The chains and chain
wheels must not be allowed to become greasy or they will slip.
After a time the chains stretch slightly, and should be shortened.
When they get worn turn them round on the pulleys.
A Tell-tale Pressure Gauge and also Ther-
Thermometer and mometer should be placed on the water-outlet
Pressure Gauge . .
pipe, and arranged, it possible, so as to be visible
in the boiler-house. In noting the temperature care must be taken
to see that there is sufficient mercury in the cup to immerse the bulb.
For covering the top of the Economiser, silicate
Non conducting cotton, slag wool, hair felt, or asbestos only must
be used. The branch pipe joints, where possible,
should always be accessible for examination, and the Economiser
protected by a light roof.
If the feed-water be impregnated with lime salts
Treatment for or otner impurities, and composition be used, it
Incrustation , .
should be introduced into the feed pipe before
entering the Economiser, by means of a small injecting pump.
Cleaning Interior Examine and clean the vertical tubes and bottom
of Tubes boxes internally at least once every twelve months.
io8 DIRECTIONS FOR WORKING
Do not allow the Soot Chamber below the
Cleaning Soot Economiser to get too full. It should be cleaned
Chamber
out once a month. The spaces between the
vertical tubes, bottom boxes, and side walls should also be
thoroughly cleaned.
To remove an accumulation of soot from the
Accumulation of i i i i i T-
tubes, shut down and empty the Economiser.
Soot on Tubes ^ 3
Disconnect inlet and outlet feed pipes. Open
all valves and pass the heat through the Economiser chamber for
several hours, keeping the scrapers constantly running while this
is being done. Before re-filling the Economiser be careful to ascer-
tain that the tubes are quite cool. The soot should not be burnt
off the tubes in this way without expert advice.
Dampness in Any Dampness in the flues, foundations, or soot
Flues chamber should receive prompt attention.
If the water in the Economiser gets too low,
°ne; immediately open the reserve flue damper
and close Economiser inlet damper, leaving
outlet damper wide open. Also open direct boiler feed valve
and close inlet and outlet Economiser feed valves. Remove
covers from soot pit manholes and open all doors into Economiser
chamber. Do not touch the safety valve until the tubes are cool.
Emptying- in Economisers fixed in exposed positions and stand-
Frost ing idle should be emptied during frosty weather.
To shut down Economiser open reserve flue
Shutting down
damper and close inlet and outlet Economiser
dampers, also open direct boiler feed valve and close inlet and
outlet Economiser feed valve.
CONCLUSION
|HE brief historical review of the development of
Green's Economiser that has been given, will, it is
thought, show that the most painstaking efforts have
been constantly devoted to its improvement. The design and
manufacture of every detail have been made the subject of special
study, and countless experiments have and are being made,
of which it is impossible to take any note in these pages. It is
sufficient to say that in its present form the apparatus represents the
experience of a firm which has for a generation been devoted to its
manufacture and working. Possessing, as Messrs. Green do, such
a lengthened and unique experience, they not unnaturally feel
confident that they produce at the present day an Economiser
which for efficiency is not excelled, and which ought not to be
lightly passed over.
T.
University of California
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