Improvements in Water-tube Steam Boilers.
Year: 1898

page_text: Date of Application, 26th July. 1893-Accepted, 29th Oct., 1898
Improvements in Water-tube Steam Boilers.
I, EDWARD JEROME MOORE, of 1734, Diamond Street, Philadelphia, Pennsyl-
vania, United States of America, Mechanical Engineer, do hereby declare the
nature of this invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
-
My invention relates to certain improvements in tubular steam boilers, especially
of the marine type and while my invention is especially designed as a marine
boiler it will be understood that it may be used as a stationary boiler.
The object of my invention is to provide the greatest amount of heating surface
in the least amount of space, and to so arrange the parts that the boiler is kept
at an even temperature at all times; a further object of the invention is to so
arrange the parts that the gases from the fuel will be thoroughly consumed; and
a still further object of the invention is to so arrange the parts that access may
be had to all parts of the boiler subject to wear; these objects I attain in the
following manner, reference being had to the accompanying drawings, in
which:
Figure 1, is a longitudinal sectional view of my improved steam boiler, the
tubes, headers and drum not being in section so as to more clearly illustrate the
passage of the products of combustion;
Figure 2 is a longitudinal sectional view through the boiler including the tubes,
headers and drums, to illustrate the water circulation;
Figure 3 is a transverse section on the line 3-3, Figure 1;
Figure 4 is a transverse section on the line 4-4, Figure 1;
Figure 5 is a sectional plan through the central header;
Figure 6 is a detached perspective view of the central header;
Figure 7 is a perspective view of one of the end headers;
Figure 8 is a perspective view of the mud drum;
Figure 9 is a perspective view of the damper;
Figure 10 is a perspective view of the saddle and side bars;
Figure 11 is a sectional view of a portion of the central header;
Figure 12 is a view shewing the arrangement when two drums are used:
Figure 13 is a view illustrating a modification shewing three transverse drums
instead of the longitudinal drum or drums;
Figure 14 is a side view, partly in section, of my improved steam boiler, shewing
a superheater and a feed water heater mounted thereon and also shewing a door
at the side instead of at the end of the boiler;
Figure 15 is a transverse sectional view of Figure 14;
Figure 16 is a section shewing the communication between the drum and the
superheater;
Figure 17 is a sectional view shewing a portion of the central header and mud
drum;
Figure 18 is a section on the line 18-18, Figure 17;
Figure 19 is a perspective view of one of the shoes for holding the central header
in place;

page_text: Figure 20 is a sectional view shewing the connection between the feed water
heater and superheater;
Figures 21 and 22 are views shewing details of one of the headers;
Figure 23 is a view shewing one of the air chambers; and Figure 24 is a per-
spective view, partly in section, of one of the side plates of the boiler.
My improved boiler may be termed a twin boiler, as it has two fire places, two
sets of heating tubes and one or more water and steam drums, common to hoth
sets of heating tubes.
A is the casing of the structure made in the present instance of sheet metal and
masonry: a a are the two front plates having fire doors a¹ and ash pit open-
ings a B B are the two fire chambers having grates b b and below the grates
are the ash pits B2 B3. Separating the two fire chambers is a central combustion
chamber C, communicating with the fire chamber B through a passage c, and
with the fire chamber B¹ through a passage c¹.
Below the combustion chamber C are two air chambers C³, C², separated from
the combustion chamber by perforated partitions ², 6; these partitions are of
the form shewn in Figure 1, so as to give the products of combustion, as they
pass through the combustion chamber, a rolling motion. The perforations in the
partitions are tapered so that the air will pass from the air chambers to the com-
bustion chamber in the form of jets, and the openings are so proportioned that
dust will readily pass through the said openings into the air chambers, while any
coal or clinkers that, may pass beyond the grates will be collected in the com-
bustion chamber C and may be removed either from the fire chambers or from
one side, if a doorway be provided as shewn by dotted lines in Figure 1.
D is the water and steam drum extending the full length of the boiler and
supported in any suitable manner.
Depending from the drum D is a central header E and two end headers F, F¹,
these end headers are connected respectively to the central header by inclined
heating tubes G G¹, so that the circulation of the water in the boiler is from the
drum 1 down the central header E, through the inclined heating tubes G G¹, up
the end headers F F into and through the drum D to the central header.
The central header E is connected to the drum D by a tube E' of sufficient size
to admit of a man passing from the drum to the header when repairs are necessary.
The edges of the openings in the drum D communicating with the headers are
connected by one or more tie rods d detachably secured to lugs on the drum, one
end of each of the rods may be uncoupled, so that the rod or rods can be turned
back so as to provide an uninterrupted opening to permit access from the drum D
to the headers.
The header E is made in the form shewn in Figures 2 and 4, so as to provide
at right angles to the tubes G G two flat tube plates e for the reception of the said
tubes consequently the central header is of greater width at the bottom than at
the top and in order to insure the proper circulation of the water in this header
I so form it at the base as to make two legs E2; the space between the legs form-
ing a portion of the combustion chamber C; and I preferably connect the two
legs together by circulating tubes e¹ these tubes in the present instance being
curved.
From the junction of the two legs E2 within the central header
a vertical partition as shewn by dotted lines in Figure 2.
may provide
The side or end plates e² of the central header E, are preferably dished, and are
each made in a single sheet secured to the flanged tube plates e, and to the flanged
bottom plates 3. The two tube plates e are curved at the top and overlap one
another to form a doubly rivetted seam, and each tube plate overlaps the bottom
plate e³, near the bottom of each leg, of the central header to form there a doubly
rivetted seam. In order to stiffen the structure, corner braces et are placed at
intervals which tie the tube plates e to the end plates 2. By dishing the end
plates, stays can be dispensed with.

page_text: I preferably make a man-hole e³ in one of the plates e2 and also make clean out
openings e in the side plates near the bottom of each leg.
Directly below the central header E is a mud drum H having a flat base so that
it will not tilt or roll. I preferably make this of cast metal.
The mud drum H is connected to the legs E by pipes h so that any sediment or
dirt settling in the legs will pass through the pipes h to the mud drum H, which
is provided with blow off pipes h¹, h', Figure 4.
The pipes extend through the combustion chamber C and are preferably
staggered, and the mud drum H is below the combustion chamber and between
the two air chambers C¹, C³, the drum has one or more clean out openings access-
ible from one of the air chambers.
The end headers F F are each made in the present instance of two sheets of
metal, suitably punched and pressed to receive the ends of the heating tubes and
caps; the flanges of the two sheets overlap at the edge and are united by a single
or double row of rivets, they are also united at intervals by tubular stay rods.
The upper portion of each end header is shaped and flanged to conform to the
drum to which it is attached, and the drum has a series of openings in it where
the end header is attached so as to allow for free circulation, and without materially
weakening the drum. The end header may in some instances be made in two
sections connected together, by nipples as shewn in Figure 12.
The drum D may be slotted the entire width of the header and reinforced, or
strengthened by tie rods if necessary.
The boiler is supported at several points, the central header at on the
foundation A¹; the end headers on the boxes a³, which extend across the furnace
above the fire door a¹; and the drum D is not only supported by the several
headers but rests on the frame. at y y, it will be seen that the structure is well
supported and balanced and the parts can freely contract and expand. Shoes are
provided on each side of the central header at the foundation so as to prevent the
header from sliding.
I is the flue which extends on each side of the drum D, as shewn in Figure 4,
and communicates with the main combustion chambers of the furnace, as shewn
in Figure 1; in the upper portion of the flue is a damper I', pivotted at . Ex-
tending from the pivot to the top of the central header E is a partition i dividing
the lower portion of the flue into two separate flues, either one of which can be
closed by the damper I¹.
The pivot shaft of the damper extends out at one side beyond the casing and
has a counter-weighted arm 12, to which are connected the two operating
cords; these cords pass under guide wheels and over wheels and extend
within easy reach of the stokers.
The damper is normally vertical, so that the products of combustion travel up
from the fire chambers between the tubes around the drum D to the flue.
When one of the furnaces is freshly charged with fuel, say for instance the
furnace B, then the damper I¹ is turned down, as shewn in Figure 1, to cut off
the direct passage to the flue from the furnace B₁ and the smoke and unconsumed
gases are drawn through the central combustion chamber C, where they mix with
heated air from the air chamber C2, which receives its hot air from one of the
ash pits, a damper being open so that the air will pass to the said combustion
chamber. The gases and hot air are thoroughly mixed in the combustion
chamber C, and are drawn into the fire chamber B where they mingle with the
products of combustion from the fire therein and are consumed, giving off the
desired heat.
In order to prevent the gases from passing up in close contact with the central
header, deflectors jj are arranged at each side of the header, so as to make the
gases pass directly over the bed of the fuel. When the smoke is consumed the
damper I is released and it resumes its vertical position, allowing the products
of combustion from each furnace to pass up independently to the flue.
The dampers 62 and 63 are hung to the framework of the furnace and each

page_text: damper is operated by a rod within reach of the stoker and the rod has a series
of ratchet teeth which engage with a lug on the frame, so that the damper can
be set in any position.
The flue I is so formed as to straddle the drum and rest upon two saddles k k
thereon and also upon two saddles k', k on the central header, it is thus supported
by the boiler structure.
A protecting plate K is placed over the upper portion of the drum D within the
flue 1, so as to protect it. This plate extends down on each side of the boiler and
is secured to the flues by the saddles k k.
As shewn in Figure 5, the end plates of the central header E are preferably
dished, thus dispensing with internal stays, although in some instances they may
be flat and stays be used without departing from the essential features of the
invention.
On the drum D are mounted a series of saddles n, preferably made in two pieces,
flanged and secured together at the centre. These saddles extend down on either
side of the drum and are secured to longitudinal bars m m, having reversely
arranged flanges; the saddles are attached to one flange of each of the bars m and
the side plates of the boiler are attached to the other flanges of the said bars.
Suitable non-conducting covering can be placed above the drum and supported by
the bars m m, as shewn in Figure 3.
By this arrangement the drum D is not punctured with a series of rivet holes,
and it is allowed to expand freely and independently of the casing.
It will be understood that in large size boilers the tube plates of the central
header may be made in two sections rivetted together, as shewn in Figure 11,
and that the end headers may be made in two or more sections coupled together;
and two or more drums may be used with the central and end headers, as shewn in
Figure 12. In the modification, Figure 13, three transverse drums are connected
together, in the place of one or more longitudinal drums.
The two lower rows of heating tubes are preferably somewhat larger than the
others, so as to allow more water to circulate in the lower portion of the boiler,
thus preventing these lower tubes from giving out first, as is the case when all
the tubes are of the same diameter.
While I have shewn the fire and ash pit openings at the ends of the structure,
they may, if necessary to suit the position of the boiler, be at one side.
Figure 14 shews a construction of boiler in which the fire doors are at the sides
instead of at the ends, so, that one fireman can fire both sections of the boiler;
in this view is also shewn the superheater and feed water heater mounted above
the boiler and sectional plates P mounted on the sides of the boiler. These
sectional plates are made as shewn in Figure 24, each section being made of two
flanged plates rivetted together with a space between them which is filled with
asbestos or other non-conducting material. The plates are provided with small
openings near the top so that they can be filled but the two plates can be secured
together after they are mounted in position on the boiler if necessary.
The plates are shaped according to the design of the boiler, in the present
instance they extend not only on each side of the boiler above the fire door open-
ings, but also extend around each end of the steam drum and may extend around
the superheater and feed water heater.
The sections P are preferably covered by a sheet metal plate P₁, which encloses
the entire side of the boiler above the fire door openings and when the fire door
openings are at the end instead of at the side this plate extends down to the base.
The superheater Q is made up of headers g and tubes q'; these headers com-
municate with the drum D through a series of passages 2, Figure 16. The super-
heater, it will be noticed, is arranged around the drum, as shewn in Figure 15,
and the tubes extend across the flues through which the products of combustion
pass.
Mounted above the superheater is a feed water heater R constructed somewhat
similar to the superheater, having headers and tubes ¹. The superheater and

page_text: feed water heater are enclosed in the casing of the boiler and projecting from the
side of the casing are flues S, Figures 14 and 15, which may be coupled to the
chimney, which Hues have suitable valves for controlling the passage of the pro-
ducts of combustion through these flues and the products of combustion can be
conveyed horizontally to any distance required. This is especially advantageous
in marine boilers for war vessels, as the products of combustion can be conveyed
to the stern of the vessel, so that in the event of the chimney being destroyed the
products of combustion can be conducted through the rearwardly extended flue.
In order to couple the superheater to the feed water heater the headers r and
are connected together by tubes 7, as shewn clearly in Figure 20; these tubes are
provided with plugs q which can be inserted to block the communication when
the two are to be used independently, but when the plugs are removed the two
can be used together as a superheater and feed water heater.
Mounted directly above the triangular central header, Figures 14 and 15, are
chambers T having perforated pipes t extending into the combustion chamber
over the inclined heating tubes G. Air is admitted to these chambers and pipes
and escapes into the combustion chamber above the heating tubes so as to aid
combustion.
Equalizing pipes u, Figures 14 and 15, may be connected to the boiler, pre-
ferably near the top of the triangular header and with the ends of the mud drum H
in order to have a better supply of water transmitted to the circulating tubes,
which terminate at the mud drum.
The circulating tubes h, as well as the connecting tube e', Figure 17, are pre-
ferably enclosed in fire brick or other refractory material, so that the products of
combustion as they pass through the furnace will not be chilled by the water
circulating in these tubes, and by heating the refractory material the tubes are
kept at an even temperature.
Passages Figure 17, are formed in the central header communicating with
the upper portion of the central chamber formed by the header with the combus-
tion chambers, so as to allow the escape of any gases that may accumulate within
the central chamber.
The supports a for the end headers, are hollow and are connected to the air
supply pipe, the front wall of each of these chambers is perforated so as to allow
a certain amount of air to pass over the five beds of the furnace.
The central header is prevented from both longitudinal and lateral movement,
by providing at each end of the foundation brackets or shoes V, which have
flanges adapted to the rounded ends of the central header, as shewn in Figure 18,
so that when these shoes are in place they prevent both the lateral and longi-
tudinal movement of the central header.
The tubes G are preferably connected to the headers in the manner shewn in
Figures 21 and 22. The tubes G are flanged into the tube plate f¹ of the
header F, as shewn in Figure 21, and each tube is threaded at the end to receive
a nut g of such a diameter and shape that it will readily pass out through the
opening in the front plate of the header, thus the tubes act as braces for the
boiler and while I prefer to provide only a certain number of tubes with the nuts
they all may be provided, if necessary. The nut is recessed to envelope the
expanded portion of the tube and is also provided with holes for the insertion of a
spanner.
The openings in the front plate of the header are closed by the ordinary
caps f³.
The headers are braced by hollow braces W, as shewn in Figure 21, each brace
being in the form of a tube threaded at its inner end, the threaded portion being
adapted to a threaded opening in the tube plate, the outer end of the tube is
expanded in the opening in the front plate and has a screw threaded end to receive
a nut w, which resists any pressure within the header. The open end of the tube
is closed by a cap w¹ which is adapted to the thread on the end of the tube.
By

page_text: removing this cap cleaning instruments can be inserted in the tube to clean the
surface of the heating tubes if necessary.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. The combination in a steam boiler, of a drum, a single central header and
two end headers suspended from the said drum and closed at the bottom, heating
tubes extending from each side of the central header to the end headers, a fire
chamber under each set of heating tubes, and a passage under the central header
communicating with the two fire chambers, substantially as herein before described.
2. The combination in a steam boiler, of a drum, a single triangular central
header having tube plates at each side, end headers raked on a line with the tube
plates of the central header and closed at the bottom and inclined tubes extending
from the tube plates of the central header to the end headers, substantially as
hereinbefore described.
3. The combination in a steam boiler, of a drum, a single triangular central.
header having tube plates at each side and communicating at the top with the
drum and forked at the bottom to form legs, two end headers and inclined tubes
extending from the central header to the two end headers, substantially as herein-
before described.
4. The combination in a steam boiler, of a drum, a triangular central header,
and heating tubes, a neck connecting the header with the drum, lugs on the drum
at each side of the neck opening, and one or more pivoted stays extending across
the drum at the opening and detachably secured to the lugs so that access can
be had to the neck, substantially as hereinbefore described.
5. The combination in a steam boiler, of a drum, a single central header and.
heating tubes extending from each side of said header, and a vertically arranged
partition in the lower portion of the header, substantially as herein before described.
6. The combination in a steam boiler, of a single central header and heating
tubes, said tubes extending from each side of the central header, a fire chamber
under each set of tubes at each side of the central header, and a combustion
chamber directly under the central header and communicating with both fire
chambers, substantially as described.
7. The combination in a steam boiler, of two fire-chambers, a central combustion
chamber, a central header forked at the bottom to form two legs, and an enlarge-
ment of the central combustion chamber, substantially as herein before described.
8. The combination in a steam boiler, of a single central header, heating tubes
connected thereto, two fire chambers, a central combustion chamber under the
central header, and air ducts opening into the said combustion chamber, sub-
stantially as herein before described.
9. The combination in a steam boiler, of a single central header, heating tubes
connected thereto, fire chambers, a central combustion chamber communicating
with the fire chambers, two air chambers under the combustion chamber and
communicating therewith, and dampers for each chamber, substantially as herein-
before described.
10. The combination in a steam boiler, of a central header, heating tubes con-
nected thereto, two fire chambers, a central combustion chamber communicating
with the said fire chambers, and two air chambers, one communicating with the
ash pit of one fire chamber the other with the ash pit of the other fire chamber,
and both communicating with the central combustion chamber, substantially as
herein before described.
11. The combination in a steam boiler, of a central header, heating tubes con-
nected thereto, a central combustion chamber, under the said header, a mud drum
at the bottom of the combustion chamber and tubes connecting the header with
the drum, substantially as herein before described.
12. The combination in a steam boiler, of a central header, heating tubes con-

page_text: nected thereto, the said header being forked at the base to form two legs, and
tubes extending from one leg to the other, substantially as herein before described.
13. A triangular header for steam boilers, forked at the base to form two legs,
the top of the header and the bottom of each leg being rounded, the said header
having its inclined sides in the form of flat tube sheets, substantially as herein-
before described.
14 triangular header adapted to be suspended from a drum, of a steam
boiler, the said heather dished end plates and flat tube plates at each side
secured to the end plates, the said tu plates adapted to receive heating tubes,
substantially as hereinbefore described.
15. A triangular header for steam boilers, forked at the bottom forming two
legs, flat tube plates and bottom plates flanged at each end, and end plates secured
on the outside to the flanges of the tube plates and bottom plates so that all the
flanges will be within the header, substantially as herein before described.
16. The combination in a triangular header, for steam boilers, having flat tube
plates at each side, and end plates with a series of corner braces securing the side
plates to the end plates in addition to the rivets, substantially as herein before
described.
17. The combination in a steam boiler, of a drum, a central triangular header,
inclined end headers, heating tubes extending from the triangular header to the
end headers, a mud drum below the triangular header and tubes connecting the
mud drum with the base of the header, substantially as hereinbefore described.
18. The combination of a triangular header and inclined heating pipes, a mud
drum connected to the header, the said mud drum having a flat base as and for
the purpose herein before described.
19. The combination in a steam boiler, of two fire chambers, a drum, a single
central header, two end headers, heating tubes extending from the central header
to the end headers, a combustion chamber between the two fire places and under
the single central header, the said combustion chamber being depressed at the
centre, air chambers, and openings in the depressed portion of the combustion
chamber communicating with the air chamber, substantially as herein before
described.
20. The combination in a steam boiler, of two fire chambers, a combustion
chamber between the two, the said combustion chamber being depressed, tapered
openings in the bottom of the said combustion chamber, and air chambers com-
municating with the said openings, substantially as herein before described.
21. The combination in a steam boiler, of a drum, a central header, end headers,
heating tubes, two fire places, a central combustion chamber enlarged at the centre
and narrow passages connecting the said combustion chamber with the fire
chambers, substantially as herein before described.
22. The combination in a steam boiler, of a central header and heating tubes,
a central combustion chamber under the central header, a fire chamber at each
side of the central combustion chamber, air chambers communicating with the
combustion chamber, and one air chamber communicating with the ash pit of one
fire chamber and the other air chamber communicating with the ash pit of the
other fire chamber, and handled dampers for each air chamber, the handles of said
dampers extending to the outside of the furnace, substantially as hereinbefore
described.
23. The combination of two fire chambers, a single central header and heating
tubes, a passage under the central header forming a communication between
the two fire chambers, two outlet passages for the products of combustion, and
means for closing one or other of said outlets so that the gases from one fire
chamber will pass under the central header to the other fire chamber and over
the fuel therein, substantially as herein before described.
24. The combination of two fire chambers, a single central header, heating
tubes in the combustion chamber of each fire chamber, a passage under the central
header communicating with both fire chambers above the grates, a single

page_text: chimney, a partition extending above the central header and into the chimney so
that the gases from one fire chamber will pass over the fuel in the other fire
chamber to the chimney, substantially as described.
or
25. The combination of a casing of a steam boiler, having a central frame
foundation A¹, bearing boxes a³, and bearings y y, fire chambers on each side of
the foundation A¹, a drum resting on the bearings y y, a central header
resting
on the frame or foundation A¹, and end headers resting on the bes
connected to the central header by heating tubes, ebstantially as hereinbefore
described.
26. The combination of two fire chambers, a passage communicating with the
two chambers-drum, a central header and end headers connected to the drum,
heating tubes, with deflectors at each side of the central header, substantially as
herein before described.
27. The combination in a steam boiler, of one or more drums, a series of
saddles mounted on the drum or drums, and longitudinal bars at each side of the
drum or drums and secured to the saddles for sustaining a suitable covering,
substantially as herein before described.
28. The combination in a steam boiler, of a drum, a series of saddles mounted
thereon, a longitudinal bar on each side of the drum, each bar having reversely
arranged flanges, the said saddles being secured to one flange, and the side plates
of the frame being secured to the other flange, substantially as hereinbefore
described.
29. The combination in a steam boiler, of a drum, a single central header con-
nected to the drum, a flue for the products of combustion directly above and
extending on each side of the drum and communicating with the two combus-
tion chambers, a partition plate extending from the central header up into the
flue, substantially as hereinbefore described.
30. The combination in a steam boiler, of two fire chambers, a drum, a single
central header connected to the said drum, end headers and heating tubes, and a
flue for the products of combustion adapted to straddle the drum and rest upon the
central header, substantially as hereinbefore described.
31. The combination in a steam boiler, of two fire chambers, a drum, a central
header, end headers, and heating tubes, a flue adapted to straddle the drum and
to rest upon the central header, leaving passages on each side of the drum, and a
vertical partition extending from the central header up to a point above the drum
so as to divide the lower portion of the flue, substantially as herein before described.
32. The combination in a steam boiler, of two fire chambers, a drum, a single
central header connected to the drum, heating tubes, a flue cut away so as to
straddle the drum and leave passages at each side thereof, with a saddle plate
extending over the drum within the flue and secured to the flue, substantially as
hereinbefore described.
33. The combination of a drum, a central header, and end headers, heating
tubes, a flue extending down on each side of the drum and communicating with
the combustion chambers of the boilers, a central partition plate extending from
the central header up to a point above the drum, with a damper, and means for
operating said damper to cut off one or the other passage, substantially as herein-
before described.
34. The combination of a drum, central header and heating tubes, a flue
circular in cross section and cut away so as to straddle the drum, the said flue
being larger in diameter than the drum so as to form passages on each side
thereof, the said flue also enlarged at the centre and having saddles resting on the
drum and central header, substantially as herein before described.
35. The combination of a drum, central header and heating tubes, of a flue, a
partition dividing the flue into two parts, a pivoted damper adapted to open both
parts of the flue or close one or the other, a lever and weight for keeping the
damper normally vertical, and ropes or chains extending over sheaves to a point
easy of access to the stokers, substantially as herein before described,

page_text: 36. In a water tube boiler, a header, a tube expanded into the tube plate of the
header and threaded, and a nut adapted to the threaded portion of the tube, the.
said nut being recessed so that the nut will envelope the expanded portion of
the tube, substantially as herein before described.
37. The combination in a water tube boiler, of a header having heating tubes
secured to the tube plate, the said tubes extending from one plate of the header
to the other, each tube being screw-threaded into the tube plate and expanded
into the other plate and having screw threads beyond the expanded portion, a nut
adapted to the screw threads, and a screw cap adapted to the tube, substantially
as herein before described.
38. The combination of a boiler of the type shewn, having a mud drum con-
nected to the boiler by circulating tubes and equalizing pipes extending from
a portion of the boiler above the circulating tubes to the mud drum, substantially
as described.
39. The combination in a boiler, of a central header, circulating tubes, a mud
drum, and a casing for the tubes made of fire brick or other refractory material,
substantially as and for the purpose hereinbefore described.
40. The combination in a boiler, of the triangular central header recessed at the
bottom to form a chamber, tubes extending across the chamber, the said tubes
being enveloped in refractory material, passages extending through the triangular
header so that the gases may escape from the top of the chamber to the combus-
tion chamber, substantially as herein before described.
41. The combination in a boiler, of a series of heating tubes, a drum, with a
series of air tubes mounted between the heating tubes and the drum, and means
for allowing air to pass through the said tubes into the combustion chamber, sub-
stantially as herein before described.
42. The combination in a boiler, of the drum, end headers, central header, heat-
ing tubes connecting the central header to the end headers, air boxes mounted
above the central header and having projecting circulating tubes extending into
the combustion chamber, substantially as herein before described.
43. The combination of a drum, end headers, triangular central header con-
nected to the said drum, inclined heating tubes, air chambers mounted above the
central header, with tubes projecting into the two combustion chambers, said
tubes being perforated, and means for forcing air into the said tubes to aid the
combustion of the gases, substantially as hereinbefore described.
44. The combination in a boiler of the type described, of a superheater consisting
of a series of tubes and headers in the form of a saddle and mounted on each side
and above the drum of the boiler and exposed to the ascending gases, substantially
as hereinbefore described.
45. The combination in a boiler of the type described, of a feed water heater
mounted above the drum of the boiler and connected to the boiler, the said feed
water heater being in the path of the products of combustion as they leave the
boiler, substantially as herein before described.
46. The combination in a boiler of the type described, of a superheater in the
form of a saddle adapted to partially encircle the drum of the boiler, a feed water
heater mounted above the superheater, the said superheater and feed water heater
being within the flue for the products of combustion, substantially as hereinbefore
described.
47. The combination in a boiler structure, of a feed water heater mounted above
the superheater and tubes connecting the superheater with the feed water heater,
means for closing the tubes when the feed water heater and superheater are acting
independently, substantially as hereinbefore described.
48. The combination in a steam boiler, of the type described, of a sectional
division plate made up of a series of sections adapted to fit around the tubes and
to separate the two sections substantially as hereinbefore described.
49. The combination in a boiler of the type described, having a drum, end
headers, a central header and connecting heating tubes, with two grates, one below

page_text: each set of heating tubes, a passage for communication between the two fire
chambers, with fire doors for the said fire chambers arranged at the side of the
boiler, so that both sections of the boiler can be attended to by a single operator,
substantially as hereinbefore described.
50. The combination in a water tube boiler, of the type described, having a
division plate, flues on either side of the generator, and means for closing the
said flues, substantially as herein before described.
51. The combination in a boiler, of a drum, a superheater mounted around the
drum and having headers, the said headers communicating with the drum through
a series of passages, substantially as hereinbefore described.
52. The combination in a boiler of the type illustrated, of air chambers sup-
porting the end headers, the said air chambers being perforated and means for
forcing air into the chambers over the incandescent fuel, substantially as herein-
before described.
53. The combination in a boiler of the type described, of the central header, mud
drum and circulating tubes, the said circulating tubes being staggered or
arranged in zig-zag order so as to more readily combine the gases and absorb the
heat from the products of combustion, substantially as hereinbefore described.
54. The combination in a boiler, of the type described, of a superheater mounted
above the boiler, and a feed water heater less in length than the superheater, both
the feed water heater and superheater being made up of headers and connecting
tubes, with short tubes connecting the headers of the feed water heater with those
of the superheater and means for closing these tubes, substantially as hereinbefore
described.
55. The combination in a boiler of the type described, of the central header,
with chairs adapted to be mounted at each side of the central header and extending
around each end thereof, said chairs preventing the longitudinal or transverse dis-
placement of the central header, substantially as hereinbefore described.
Dated this 96th day of Lu... 1000
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.