Improvements in Travelling Grate Furnaces.
Year: 1893

page_text: Date of Application 12th Dec., 1893-Accepted, 25th May, 1894
Date of Application 12th Dec., 1893-Accepted, 25th May, 1894
COMPLETE SPECIFICATION.
Communicated from abroad by ECKLEY BRINTON COXE, of Drifton, in the
County of Leuzerne and State of Pennsylvania, United States of America,
Mechanical Engineer.]
Improvements in Travelling Grate Furnaces.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby
leclare 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 :-
This invention relates to that class of travelling-grate furnaces which are more
especially designed for burning the finer sizes and lower grades of coal.
The objects of the invention are to furnish an improved furnace of that class
which shall be adapted to be manufactured of large size and have an improved
travelling-grate, or furnace-floor, composed of removable sections combined with
improved means for supporting and operating the same; also to provide effective
means for igniting the fuel; a fluid seal for preventing leakage; improved means
for preventing too rapid combustion of the fuel along the edges of the travelling-
grate; means for driving and regulating the speed of the grate and blower, and
improvements for burning two successive supplies of fuel in the same furnace.
In the accompanying drawings
Figure 1 is a sectional side elevation of a travelling-grate furnace-plant
embodying my present improvements, the view being taken on the line b, b
Figure 2.
Figure 2 is a plan view of the furnace, with some of the upper portions shown
removed for illustrating certain details.
Figure 3 is a front elevation of the furnace as seen from the right hand in
Figures 1 and 2, and showing one side of the furnace in section on line a, a Fig. 1,
for illustrating more in detail the internal construction of the furnace and of its
mechanism.
Figure 4 is an enlarged plan view, similar to a portion of Figure 2 of a portion
of a grate-beam and its floor-plates.
Figure 5 is a side view of the parts shown in Figure 4.
Similar figures or letters of reference indicate like parts in all of the figures of the
drawings.
The furnace-chamber, designated by C, has a floor composed of a travelling
grate, and is enclosed at the ends and sides thereof by suitable walls, and is
covered by a suitable roof, herein designated by A. The side-walls 2 and 4 extend
downwardly to the foundation on which the furnace is set, the upper portions of
5 said walls 2 and 4 being ordinarily composed of fire-brick. The front end-wall of
the furnace is shown composed of the upper portion 3, and the lower portion B see
Fig. 1; said lower portion being inclined, and constituting an ignition-block, or
table, for the purpose hereinafter described. At the rear of the furnace-chamber
is the usual bridge-wall 7, between which and the roof of the furnace is the outlet-
0 passage 8, for the heated gases.
The endless grate, designated in a general way by G, is carried upon chain
wheels 12, and 14, which are fixed upon the shafts 13 and 15 Fig. 1, that ar
supported in suitable bearings, 16 and 17 see Fig. 2, on the framework of the
furnace. The upper and lower runs, 10 and 11 Figs. 1 and 2, of said endless grat
15 are supported by guide-ways, 18 and 19, respectively, and the entire grate
mechanism is set upon an incline toward the ignition-block or table B, (se

page_text: Figure 1) and so that the forward end of the lower run thereof dips below the
water-line w of the air-seal tank K, hereinafter more fully described.
The travelling-grate consists of a series of transverse beams, N Figs. 1, 3 and 5,
carrying the floor-plates, or grate-bars proper, of the furnace-floor; which beams
are carried by a pair of endless chains, 50, consisting of a series of alternating
links 63 and 64, connected together by pivot-pins or rivets, preferably as shown in
Figure 4. In this preferred form of the grate-mechanism chains, said intermediate
link 63 is double, consisting of two plates, 631-63" (Figures 1 and 4) placed side
by side as there shown; and the beam-carrying links 64-641 are placed outside
of said intermediate links to form the space 64" for receiving the depending
lugs 66, (see Figure 5) of said beam. Said depending lugs are perforated with
holes corresponding to the holes 65 of said beam-carrying links, the described
parts being held together by ordinary bolts removably inserted in said holes,
whereby the beams, together with the furnace-floor plates carried thereby, may
be removed from the chains and replaced thereon as occasion may require. This
operation is, in practice, best carried out at the rearward end of the furnace, the
workmen, for this purpose, entering the rearward portion C¹ Fig. 1 of the grate-
mechanism chamber, through the door 78.
The grate-bar, or floor-plate, considered as a whole, consists of the beam N,
having on its upper side (or itself constituting) a fuel-supporting plate P, and an
upper-plate M, set at some distance above said supporting plate and perforated
by holes 41, for the passage of air through the fuel thereen.
When the floor-plates are assembled for use, as in Figure 1, the lower plates P,
of the successive grate-bars or beams, are set at a distance apart to provide an
air-space 33, through which an air-blast from below may pass up into the horizontal
spaces 6, respectively between said lower plates P, and upper plates M.
The perforations 4' of the upper plates are shown formed conical, largest at
the upper end, so that the fine fuel therein will, when the plates are inverted, as
when going along the under run of the endless grate, run out of said holes and
thus free the upper plate ready for use again.
The upper-plate is shown formed in several sections, 10¹ and 10¹, set end to
end to form one continuous surface; in Figure 4, however, one of those sections
is omitted for the purpose of more clearly illustrating the arrangement of the
several details. The upper plates are shown furnished with the supports or
posts, 71, (which posts may, if preferred, be formed upon the lower plates P)
and are also provided with fastening pins 9, secured in the upper plate by
means of the enlarged head 9', embedded in said plates, and which pass through
the holes 13' in the lower plate and are bent thereunder to form the retaining
hooks 151.
The grate beans are so disposed that the grate bars of one beam will, when
in horizontal alignment, overlie the grate bar of the next adjacent grate beam
to cover the space between the said beams and prevent the fuel passing through
the grate and being wasted.
As a means for actuating the chains of the grate-mechanism, these are shown
carried by the wheels 12, and 14, which are fixed on the forward and rearward
chain-wheel shafts 13 and 15, respectively. These shafts are supported in ordinary
bearings 16, 16 and 17, 17¹ on the framework, and the shaft 15 is provided at one
end with the worm-wheel 40, Figures 2 and 3, which meshes with the driving-
worm 41, on the feed-shaft 42; this shaft is shown supported in the bearing 43
(also carried by the framework of the furnace) and is provided with suitable
means, as, for instance, the pulley 44, whereby it may be actuated for driving the
grate-mechanism.
The transversely-disposed grate-beams N being set upon their carrying-chains 50
edgewise thereto and to extend outwardly therefrom, and the furnace-floor plates
being carried on the projecting edges of said beams at some distance from the
chains, these plates are naturally separated by a considerable distance while passing
over the chain-wheels, as will be understood by examination of Figure 1. This

page_text: ULLIS
paration of the beams and plates serves to break up the layer of cinder as
sses out of the furnace-chamber, and also to provide at that part of the furnace
sufficient space between the successive floor-plates to permit of the removal and
placing of these plates (when these are separably carried on the beam as herein
own) during the operation of the furnace.
For supporting the upper and lower runs 10 and 11 of the endless travelling
rate, the furnace-frame is provided on either side thereof with the upper and lower
aide-ways or supporting tracks 18 and 19, respectively. The upper track 18
pports the upper-run 10 of the endless beam-carrying chain. The corresponding
wer track 19 bears against the under sides of the floor-plates M as illustrated in
igures 1 and 3. For protection, in practice, of the ends of the grate-bars, and
Iso for preventing the fine fuel passing over the ends thereof, the side-walls of
he furnace are brought inwardly over the grate-bars as shown in the sectional
iew, Figure 3.
Immediately underneath that portion of the travelling grate which forms the
oor of the furnace-chamber is placed an air-supply consisting of a multiplicity of
ir-boxes, a, b, c, d see Fig. 1 which, in practice, may be separately supplied with
ir through a corresponding series of supply-pipes, a, b, c, d, respectively; these
pipes are shown connecting with a larger pipe O, leading to some suitable source
of air-supply, as, for instance, an air-pump, or the pressure-blower L Figs. 2 and 3.
The air-supply pipes are shown furnished with regulating valves, as at b¹¹, whose
operating handles or levers are berein designated by all, cand d
respectively see Fig. 2. By means of these regulating-valves, the pressure of
the air supplied to the successive portions of the travelling furnace-floor over the
chambers a, b, c and d, respectively, may be varied for gradually reducing the
pressure of the air-blast applied to the fuel during the later stages of the combustion
thereof, as hereinafter more fully set forth.
The driving apparatus for actuating the travelling grate comprises the described
shafts and chain-wheels, and some suitable means for applying power thereto, as,
for instance, the worm-wheel 40, fixed on the outer end of the shaft 15 Fig. 1, and
the driving-shaft 42 carried in hearings on the framework and having a worm 41
meshing with said worm-wheel, this shaft being provided with a pulley 44 or other
device whereby power may be applied thereto.
The blowing-machine L preferably consists, as indicated in the drawing, of an
ordinary fan blower, which may be of the class known in the market as a
pressure blower"; or, in some cases, a piston blower may be substituted for the
fan blower.
"
The mechanism-actuator M² may consist, as indicated in the drawing, of a steam-
engine, the one herein represented being shown of the so-called "Westinghouse" type,
and comprising a framework 20, two cylinders 21 and 22, aud a valve-chest, 23, to
which steam is supplied from the boiler B', through the pipe 24, in which is
shown a valve 25, for admitting steam to the motor M2 and for regulating the
speed thereof. The shaft 26 of the motor M extends to the blowing-machine L
for driving the same, and is shown provided, on the opposite end thereof, with
the driving-pulley 27, which is shown directly connected by a belt 28, with the
aforesaid driving-wheel 44 on the shaft 42 of the grate-driving apparatus D.
By this means or other well-known means similar thereto, the blowing-machine
is directly and positively connected with the driving apparatus of the endless grate,
so that proportionate working movements will be imparted thereto; and said
connection is such that if the speed of one be varied, the speed of the other will
be proportionately varied. This variation may be effected by opening or closing
the ordinary stop-valve 25 in the steam-pipe 24, so as to vary the speed of the
mechanism-motor M².
By varying the speed of the motor, or mechanism-actuator M², the working
5 movement of the blowing-machine L will be changed; and also the working
movement of the travelling grate will be correspondingly changed, and the
pressure of the air-blast in each of the series of chambers a, b, c, d, will be changed

page_text: in varying ratios, depending upon the relative pressures therein. By reason of the
organization described, the air-pressures in the successive chambers will be changed
in different ratios, the lower pressures being varied by a different amount, propor-
tionately, on the reduction or increase of the speed the blowing-machine and
travelling grate. This peculiar effect, or result, is one of the objects of my
invention, since a different grate-speed and consequent difference in the rate of
combustion of the fuel, properly requires such a variation as herein set forth in the
ratios of the air-blasts.
It will be understood that, in practice, some leakage of air takes place at each
end of the air-supply apparatus, the leakage at the right hand in Figure 1 passing
out between the grate and the flange 29, of the air-box a into the forward portion C
of the grate-mechanism chamber; and the leakage at the rearward end, from the
lower pressure air-box d, passing out between the grate and the flange 29¹ of said
air-box into the rearward portion C of said grate-mechanism chamber. Some
leakage also occurs through the mass of fuel on the chain-grate at the extreme
forward end of the furnace chamber, (at the right-hand in Figure 1) and thence
forwardly and downwardly through the chain-grate into said forward portion C"
of the grate-mechanisin chamber. But the forward leakage described I find to be,
in practice, much the greatest, owing, presumably, to the higher pressures used in
the forward air-boxes a and b, and the very much less pressure used in the rearward
air-box d. If, therefore, no cut-off be provided between the forward and rearward
portions C and C" of the grate-mechanism chamber, the high-pressure leakage
from the forward end of the grate would pass downwardly and then rearwardly and
upwardly to the space 30 between the rear wall of the furnace and the rearward
portion of the upper run 10 of the travelling grate, and from thence would pass
upward through the extreme rearward end of the furnace-chamber into the discharge-
flue and thus be wasted. To overcome this leakage and consequent waste, and by
overcoming the same to more fully utilize the entire air-blast for the purpose of
burning the fuel, the forward portion C" of the enclosed grate-mechanism chamber
is divided off or separated from the rearward portion Call of said chamber by
means of a cut-off device extending across said grate-mechanism chamber at a
point in the length thereof intermediate to the forward and rearward ends of the
upper run of the travelling-grate. Said cut-off comprises a transverse wall,
which, in the form of the apparatus herein shown consists of the air-box a that
extends downwardly into a body of fluid, as 70 Fig. 1, held in a suitable tank, K,
which extends across the width of said grate-mechanism chamber and to the lower
side thereof. Said tank consists, in the preferred form thereof herein shown, of
the bottom-plate 62, the forward-plate 621, and the side-walls, 6211 and 62111 Fig. 2;
and the fluid (which, of course, is usually water) should rise, in practice to about
the height shown in the dotted lines in Figure 1, so as to entirely cut off com-
munication between the two portions aforesaid of the grate-mechanism chamber.
By these means the endless grate is returned to the front of the furnace through a
passage-way closed to the air-blast; and is also thoroughly soaked by the water
in the air-seal tank for a considerable period of time, for loosening the residue of
ash and cinder, which, in practice, will adhere to the grate-bars when these
out at the rear end of the furnace-chamber, thereby cleaning the grate-bars ready
to be again brought into use. The debris thus removed from the travelling grate
is naturally collected in the lower portion of the water tank K, and may be
removed from the front of the furnace through the passage at 60 between the front-
wall 621 of said tank and the lower edge 67 of the front end-wall 61 of the furnace-
mechanism chamber. To provide for this operation, the front-wall 621 is set
inclined, thus furnishing a clear space through which to insert a hook or drag for
bringing up the sediment out of the bottom portion of the tank.
pass
The several division-walls or partitions of the air-supply chambers come up
close to the under side of the grate beams N, and are shown furnished at their
upper edges with the horizontal tables or ribs 32, of a width about equal to the
distance, longitudinally, of the furnace, between said grate-beams. By this means,

page_text: when the grate-mechanism is carried along over the air-chambers and the beams
come to the position shown, for instance, in Figure 1, said tables cut off any strong
currents of air from one chamber to another by way of the spaces 33, between the
grate-bars. In practice, however, the leakage between the partition-walls and the
lower edge of one of the beams N, when this beam stands over said partition wall,
together with the leakage through the spaces in the furnace-floor plates, is sufficient
to furnish the necessary air-blast for the narrow portion of the grate thus temporarily
cut off from the main air-supply. But any such leakage from one chamber to the
next succeeding chamber is not usually sufficient, in practice, especially when the
parts are fitted as they should be to run in close proximity the one to the other, to
furnish the second air-chamber with a sufficient air-supply; this deficiency is made
up by a proper adjustment of the regulating valves.
For supplying fuel to the furnace, this is shown provided with a fuel-hopper,
designated in a general way by H Figs. 1 and 2, and which consists of the inclined
lower wall 5', the forward wall 5, and the usual end-walls 5" and 5111. The hopper
is also usually provided with a sliding gate 34, for regulating the discharge of fuel
therefrom.
Between the hopper H and the furnace-floor, I place the inclined ignition-
block B, over which the fuel passes to the furnace-grate, and which is formed of
refractory material such as fire-brick or fire-clay. Said block is usually supported
on a suitable plate, or beam, as 35, of the furnace structure.
The ignition-block is set in close proximity to the grate and with its inclined
face 23 in substantial alignment with the normal "angle-of-repose" of the fuel, so
that the stream of fuel descending over said block will be subjected in a layer of
substantially uniform thickness throughout its length to special treatment by
heating without aëration preparatory to ignition. The ignition-block is designated
as "non-aërating" for the reason that it is made of close texture or material, so as
to protect the fuel during the preparatory heating from the admission thereto of
air from below; this would tend to prematurely ignite the fuel, and would also cool
the said block and thereby prevent the proper under-heating of the fuel.
At its inner side the block B is shown terminating abruptly at 21' in a wall,
which is designated the "falling wall"; this wall extends downwardly close to the
grate, and through this upright surface the block B receives a considerable
proportion of its heat; for, by means of my present improvements, the fuel is fully
ignited close to said wall, thereby effectively heating the same; for these purposes,
the falling-wall should have a height substantially equal to the thickness of the
fuel-stream upon the ignition-block, so as to thoroughly reform the relatively thin
layer of fuel as this falls over said wall, into a relatively thick layer upon the
grate. The pre-heated layer of fuel having been thus mixed and re-formed into a
thicker layer contiguous to the falling-wall, it is there subjected to an air-blast
through the grate and suddenly and fully ignited. The roof A of the furnace-
chamber reflects a portion of the heat-waves backward and downward upon the
ignition-block thereby increasing the efficiency of this part of the apparatus.
The construction and organization of the several parts is such that the thickness
5 of the inclined fuel-column 22 is naturally less than that of the mass 2211 spread
upon the furnace-floor; and the inclination of the surface 231 of said ignition-
block being raised but little above the angle of repose of the fuel, the thickness of
the descending stream 22 of the fuel is reduced to a minimum, thereby permitting
a considerable amount of heat to pass through said stream of fuel and be absorbed
0 by the ignition-block; this heated block being below said fuel-stream, operates to
heat this from the underside as soon as the fuel comes upon said block B. For it
will be understood that the direct action of the furnace-gases requires some time
for permeating through the descending stream of fuel, and will also be most
effective for the direct ignition of the fuel over the lower portion of the inclined
5 surface 23 of said ignition-block. In effect, therefore, my improvement operates
not only to thinly spread the fuel as this enters the furnace and thus expose the
same more fully to the direct action of the heated furnace-gases before it is massed
..

page_text: in a thicker layer on the travelling grate, but the heat absorbed by the ignition-
block from the igniting fuel over the lower side thereof is transmitted through
said block upwardly to the fresh fuel as this first passes onto said block.
The endless grate being set upon an incline as shown, and the air-blast chambers
being correspondingly set, and the tendency of the air-blast being to pass directly
(by the shortest distance) through the grate and the layer 22" of fuel thereon, the
heated gases of the furnace are thereby naturally blown first toward the forward
end of the furnace, so that said gases are thereby much more strongly than
otherwise thrown against the descending layer 22 of fuel upon the ignition-block B.
By this means the fuel-supply is much more thoroughly heated before being
delivered to the grate for combustion; and also owing to the forward direction of
the air-blast as this passes through the fuel, the gases are driven first forward and
upwardly in the chamber C, and then follow backward along under the heated
roof of the furnace, being thereby thoroughly mixed and the combustion of the same
greatly promoted. Also, the gases impinge upon the nearly spent fuel near the
rear end of the furnace-chamber thereby more effectively burning the same, with a
minimum supply of air supplied thereto.
The fuel being spread in a mass upon the grate, usually about to the height of
the line g―g and being carried forward by the travelling-grate alongside of the
stationary side-wall 2 of the furnace, partakes of the action of a stream, the
extreme edge portion of the mass bearing against said side-wall being held back
by the friction, will be subjected for a longer period to the air-blast and thereby
naturally become more quickly burned out. This is the action which would
naturally take place, (especially with the fine fuels for the burning of which this
furnace is especially designed,) if the side-walls of the furnace were, as in the
usual practice beretofore, set vertically to the plane of the grate. This defect is
overcome by supplying an excess of fuel to the edge of the grate so as to retard
the burning of the same and thus cause the fuel along the edges of the grate to be
consumed at substantially the same rate as that along the middle portions of the
furnace. For securing the required excess of fuel, the side-wall 2 of the furnace
is set longitudinally of the line of travel of the grate and immediately over the
edge thereof, and is constructed to have an outward and upward inclination from
the grate. By this means the fuel coutained, for instance, within the triangular
space Figure 3, gradually descends, as it is consumed, downward upon the grate
immediately adjacent to the line - thereby adding by so much to the fuel and
the cinder therefrom lying upon the grate between the vertical lines h―h, i-i.
This excess of fuel not only furnishes supply for counteracting the effect of the
retardation of the forward.movement of the fuel which is adjacent to the side-wall
of the furnace, but serves to pile upon the grate-space between jj and han
extra quantity of ash and cinder for properly covering that portion of the grate
during the later stages of the combustion.
As a further means for retarding the combustion of the slowly moving fuel
which is adjacent to the side-walls of the furnace, and in connection with the
inclined side-walls for securing the proper excess of fuel along said walls, I provide
means for supplying a cooling-circulation to said side-walls, whereby the combustion
of the fuel is retarded and controlled so as to be completed simultaneously, or
substantially so, with that of the fuel carried upon the more central portions of
the grate. In Figure 3 I have shown the inclined side-wall 2' consisting of the
inner side of the hollow block, 87, set upon the top-flange of the side-plate 90 of
the furnace structure, the interior space 88' being filled with water. The inclined
side-wall of the furnace extends lengthwise of the furnace substantially parallel
with the line of movement of the grate, and over the series of air chambers a, b, c, d
which chambers are, as hereinbefore mentioned, provided with means for varying
the air-pressure therein so as to properly control the combustion of the fuel at the
-corresponding successive points in the length of the furnace.
The horizontal dotted lines e-e, -f and g-g which are drawn at successive
heights, respectively, relatively to the grate and to the inclined side-wall, in
.

page_text: 5
igure 3, are intended to correspond substantially with the normal neigut,
said side-wall, of the upper surface of the fuel at the successive points in the
ngth of the furnace indicated by the vertical lines e¹-e¹, f-fi and g¹-g',
igure 1. When the fuel is supplied to the furnace at a suitable depth, indicated
or instance at k, Figure 1, it is, in practice, first ignited and brought into a high
ate of combustion over the first air-chamber a; from thence it is carried along
ver the second air-chamber b, where it is further consumed and therefore somewhat
educed in depth, as indicated at the line -, from thence it is carried forward
nd very much reduced in thickness as the combustion approaches completion, as
adicated by the line e-e, after this it is carried forward over the last air-chamber d
where the combustion is fully completed, and is then carried on to be finally
isposed of. At the first point gly, the fuel lies against the inclined side-walls
or a considerable portion of their height, as indicated by the line g-g Figure 3.
At the point f, Figure 1, the fuel is lowered to about the line f-f, Figure 3,
and at the point ee Figure 1, is further lowered to about the line e-e, in said
Figure 3. As the described lowering of the mass goes on, the portion of fuel, in
the triangular space between the inclined side-wall and the line -h, Figure 3,
lides down said inclined wall and is deposited upon the grate between the lines 4-h
and i-i, Figure 3, thereby accumulating upon this edge-portion of the grate an
excess of cinder over that naturally formed upon the more central portions of the
grate.
During the forward motion of the burning fuel, and because of a slight opening
along the sides of the travelling-grate, an extra quantity of air would usually be
supplied to the fuel on the edges of the grate; this would naturally hasten the
combustion at these points in excess of that over the middle portions of the grate.
This difficulty is overcome by use of the air-check or packing devices, as follows:
The floor-sections or grate-bars, which lie side by side transversely of the furnace,
are, in practice, substantial duplicates but the ends of said sections are in
approximately alignment only, so that the narrow space at 79 which normally exists
between the floor-sections and the fixed side-wall 2 of the furnace-structure, will
vary in size at different points along the furnace-floor. As a means for substantially
closing said side-space against the air-blast underneath the furnace-floor, an
inclined track or ledge 85 is provided alongside of the grate, in position for
supporting a series of gravity-operated air-check rods, 84, against the ends of the
floor-sections, as will be understood by reference to Figure 3. Said rods 84 should,
in practice, be of but moderate length, as indicated, for instance, in Figure 4, so
as to conform more accurately to the varying positions of the ends of the grate-
bars as these travel along in the furnace. Said air-check bars are shown round in
section, (see Figure 3), so as to roll freely down the inclined surface of their
supporting track and bear against the edge of the grate. In practice, the extreme
ends of the air-check rods 84 are rounded, as indicated in Figure 4, so as to pass
over the slightly-projecting corners of the grate-bars. It will, of course, be
understood that the described air-check apparatus is not intended to absolutely
close the side-passages 79 along the edge of the grate against the air-blast, but to
substantially close the same against any excess of such air-blast and thus reduce
the air-supply at the edge of the grate to or below that of the other and more
central portions of the grate.
The first supply of fuel is delivered to the endless grate from the supply-hopper H
In the roof or arch A,
over the ignition-block, as herein before described.
rearward of the ignition-block B Fig. 1, is an opening 85' through which to
supply the grate with an additional quantity of fuel, usually of another grade.
Rearward of the furnace-roof A, an ordinary steam-boiler B', is shown in place
for being heated by the gases from the furnace, and to supply steam for driving
the engine or motor M².
As a means for regularly delivering the additional fuel-supply to the furnace-
chamber through said opening 85', a feed-apparatus is shown set above said opening,
and comprises a hopper H', suitably supported, and a feed-wheel or bucket-wheel, W,

page_text: set underneath said hopper in position for receiving the fuel therefrom and
delivering the same in a falling stream, 86, into the furnace-chamber, as illustrated
in Figure 1. For actuating said feed-wheel, the shaft 89 of said wheel is furnished
with a pulley or chain-wheel, 96, which is connected by a driving-band or chain, 97,
with a chain-wheel, 95, fixed on the shaft 15. By making the wheels 95 and 96 of
proper relative dimensions, any required speed may be imparted to said feed-wheel,
for delivering to the furnace any required proportion of the secondary fuel.
The general operation of the invention is as follows:-The steam-engine or
other actuator M' being set running, power is transmitted therefrom to and through
the driving-apparatus to the grate-mechanism of the furnace, to move the upper
run of the grate toward the left-hand in Figure 1. During this time the fuel from
the hopper H runs downward onto the grate, forming a layer 22" which being
burned as it passes through the furnace-chamber C, the cinder is finally discharged
from the rearward end of the travelling-grate. At the same time the motor M'
actuates the blowing-machine L to supply air, through the conduits and air-
chambers, to the upper run of the travelling-grato which constitutes the furnace-
floor; the supply of air to the several chambers a, b, c, d, (when a series of these
are used,) being regulated by the air-valves in the several distributing pipes
described. Upon any change of speed of the motor M³, the velocities of the
blowing machine and of the travelling grate, these two mechanisms being directly
connected for proportional movements, are correspondingly changed, so as to
supply to the furnace proportionate amounts of fuel and air for effecting the proper
combustion of the fuel whether the rate of combustion of the same be greater or
less, within ordinary limits. The first supply of fuel is fed from the hopper H,
over the ignition-block, and is delivered to the grate at a point adjacent to the first
air-supply chamber a, each section of the grate receiving its fuel at or before the
time it reaches said chamber, and being then carried along over that chamber and
the succeeding chambers b, c and d. During this period the combustible material
of the fuel is consumed, and the resulting cinder, or ash, is afterward carried under
the bridge-plate 7, and finally delivered over the rearward end of the grate into
the ash-pit 36. In practice, the combustion goes on, at one stage or another,
throughout nearly the entire length of the furnace-chamber, the ignition taking
place within a short distance of the point where the fuel falls upon the grate, and
the fuel being completely reduced to cinder over the last chamber d of the series.
The cinder is carried back upon the travelling-grate, under the wall 7, at the
rearward end of the grate, as shown at the left hand in Figure 1, and is discharged
from the grate-sections or plates into a pile at 36, which may be removed from
time to time in any convenient way, as through the door 78, without interrupting
the operation of the furnace.
After the furnace has been put into complete operation, the fireman can, by
means of the air-valves in the air-supply partitions, readily regulate or vary the
pressure in the successive air-chambers, to produce the best results and completely
reduce the fuel to cinder before it reaches the wall 7; also to keep the furnace-
floor well covered, and to burn the combustible of the fuel with a high degree of
economy. By increasing the air-blast during the earlier portion of the combustion
period, the fuel will be more rapidly consumed; or by decreasing the pressure in
the rearward air-supply chambers, the grate may be travelled more slowly and the
combustion prolonged so as only to consume the combustible of the fuel just before
this reaches the bridge-wall.
During the regular operation of the furnace, the first layer or supply of fuel is
ignited at a point adjacent to or over the first air-blast chamber a, which chamber
is, in practice, supplied with air at a moderate pressure. The air-blast chamber b
is ordinarily supplied with air at a considerably higher pressure, for the purpose of
increasing the combustion and raising the burning mass to a high temperature.
During or immediately following the thorough ignition of the layer 221 of fuel,
the secondary supply of fuel is delivered to the furnace chamber, being deposited
in a layer 72, superimposed upon said ignited layer 22" of fuel from the hopper H.

page_text: n practice, said secondary supply is intended to be of a relatively low grade,
uch, for instance, as carbonaceous slates and minerals found in connection with
eins of pure coal. The secondary fuel being delivered into the hot furnace-
chamber upon a bed of fuel already brought to a high state of combustion, the
carbon is rapidly distilled therefrom and mingled with the furnace-gases, to be
consumed in the rearward portions of the furnace-chamber; the refuse mineral
being finally carried off with the ashes and cinder from the higher grade of fuel
forming the first layer upon the furnace-floor.
By means of the improved furnace herein described, carbonaceous minerals
having a very low proportion of carbon may be advantageously utilized in
connection with the ordinary grades of coal, even when such minerals may not be
capable by themselves of supporting combustion.
The air-pressures in the chambers c and d will when only the first fuel-supply is
used, be normally less than in the air-blast chamber ; but when two fuel-supplies
are used, owing to the increased depth of the mass of fuel beyond the point where
the secondary supply is delivered to the grate, the air-pressures will ordinarily
require to be increased in one or more of said chambers, for forcing the air through
both the primary and secondary layers of fuel.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. The combination in a furnace, of an endless travelling-grate comprising chains
running longitudinally of the furnace, transversely-disposed grate-beams secured to
and carried by said chains, independent floor plates carried by said grate-beams,
and mechanism for supporting and actuating the chains, substantially as described.
2. The combination in a furnace, of an endless travelling-grate comprising two
or more endless chains disposed longitudinally of the furnace and composed of a
series of pivoted links having the alternating spaces or openings 64", the
transversely-disposed grate-beams supported by said chains and having depending
flanges which fit and are secured in said openings between the link-plates, floor-
plates removably supported on the grate-beams, and driving-mechanism for
actuating said chains, substantially as described.
3. The combination in a furnace, of an endless travelling-grate comprising a
series of chains running over vertically rotating sprocket-wheels, a series of
5. transverse grate-beams secured to said chains and having flanges contiguous to said
beams, a series of grate-bars secured to each grate-beam aud relatively so disposed
that the grate-bars of one beam will, when the grate-bars are in horizontal
alignment, partially over-lie the grate-bars of the next adjacent grate-beam to
cover the space between beams and prevent the fuel from passing through the
O grate and being wasted, chain-wheels for driving said chains, and means for
actuating said wheels, substantially as described.
4. In a furnace, the combination with an endless travelling-grate having
transverse grate-bar supporting beams, of a series of air-supply chambers located
under the fuel-carrying run of the grate, the walls of which chambers have flanges
5 or tables at their upper ends of sufficient width to cover the space between adjacent
grate-beams, substantially as and for the purpose described.
5. In a furnace, a series of longitudinally-travelling endless-chains mounted upon,
and running over vertically rotating sprocket-wheels supported upon shafts
journalled in bearings outside the frame or walls of the furnace, grate-beams
O transversely and remotely-disposed secured to said endless-chains in combination
with an air-receptacle interposed between the upper and lower runs of said endless-
. chains and divided into a series of air-chambers by vertical transverse partitions
having flanges or tables at their upper ends of sufficient width to cover the space
between adjacent grate-beams, substantially as and for the purpose described.
$5. 6. The combination, in a furnace, with chain-carrying shafts and wheels, and
with a pair of endless chains carried on said wheels, of a series of transversely-
B

page_text: .
disposed grate-beams carried by said chains and set vertically to, and outside of,
the chains, and provided at their outer edges with furnace-floor plates of a width
to form a continuous furnace-floor between the chain-wheels, whereby said furnace-
floor plates on one beam are separated from the plates of the adjacent beam while
passing over the chain-wheels, substantially as described.
7. In a grate or furnace-floor, the combination with a fuel-supporting lower-
plate, of a perforated upper-plate set at a distance above said lower-plate, there
being lateral space between said plates for the admission of air to the perforations
of the upper plate, substantially as described.
8. In a grate or furnace-floor, the combination with a series of fuel-supporting
lower-plates set side by side at a distance from each other and having an air-passage
between the edges of the same, and with chains and driving mechanism for carrying
forward the lower plates, of perforated upper-plates set at a distance above said lower-
plates, respectively, and set edge to edge to form a substantially continuous furnace-
floor surface and having a space between said upper-plates and lower-plates for
admission of air from said lower-plates air-passage to the perforations of the upper-
.plates, substantially as described.
9. The combination with a travelling grate, and with means for supplying the
grate with fuel spread in a layer thereon, of a side-wall over the edge of the grate
and in close proximity thereto and in substantial alignment with the line of move-
ment thereof, and set inclined upwardly and outwardly therefrom, whereby an
excess of fuel is supplied to the grate along the edge thereof, substantially as
described and for the purpose specified.
10. In a furnace, the combination with a travelling grate, and with means for
supplying the grate with fuel spread in a layer thereon, of a hollow side-bar over
the edge of the grate in close proximity thereto and in substantial alignment with
the line of travel thereof, and having its inner side set at an inclination upwardly
and outwardly from the surface of the grate, and means for supplying a cooling-
circulation against said inclined wall, whereby an excess of fuel is supplied to the
grate along the edge thereof, and whereby the combustion of such excess of fuel is
controlled, substantially as described and for the purpose specified.
11. In a furnace, the combination with a travelling grate, or furnace-floor, of a
series of air-supply chambers located under the furnace-floor at successive points
longitudinally of the furnace, means for supplying air to said chambers at varying
pressures, a feed-supply for supplying fuel to the grate over the first of said air-
chambers, and a side-wall located in substantial alignment with the line of travel of
the grate and extending lengthwise of the furnace over the series of air-chambers,
and having an outward and upward inclination from the surface of the furnace-floor
whereby an excess of fuel is supplied to the grate along the edge thereof, and
whereby the combustion of such excess of fuel is controlled at successive points
along the length of said inclined side-wall, substantially as described.
12. In a travelling grate furnace, the combination with the travelling-grate
comprising a series of bars transversely thereof and having their ends in approximate
alignment, of the inclined track or ledge alongside of the grate, and a series of
gravity-operated air-check rods supported on said track and ledge in position for
normally bearing against the ends of the floor-sections, substantially as described.
13. In a furnace, the combination with the travelling grate, or furnace-floor, and
with an air-supply below said furnace-floor, of a fixed side-wall alongside of and
adjacent to the edge of the furnace-floor, there being an air-space between said
side-wall and said furnace-floor edge, an inclined side-wall immediately over and
alongside of the edge of the furnace-floor and having an inclination upward and
outward as set forth, and the air-check rods intermediate to and bearing against
the edge of the grate and the side-wall alongside of said grate-edge, whereby the
excess of fuel supplied to the grate along the edge thereof is protected from an
excess of air-blast, substantially as described.
14. In a furnace, the combination with the enclosed grate-mechanism chamber
and the endless travelling grate located therein, of a cut-off separating the

page_text: grate-mechanism chamber into two parts and having an air-sealed passage-way for
the lower run of the travelling-grate, substantially as described.
15. In a furnace, the combination with the enclosed grate-mechanism chamber,
and the endless travelling-grate located therein, of a series of air-supply boxes.
underneath the upper run of the grate and the furnace-chamber, means for varying
the pressure of the air in said air-boxes, and a cut off having an air-seal grate-
passage and separating the forward and rearward portions of the grate-mechanism
chamber, said endless grate returning through said air-sealed passage-way,.
substantially as described.
16. In a travelling-grate furnace, the combination with the enclosed grate-
mechanism chamber having an opening 60 in the end-wall thereof, the travelling
grate, and a fluid-tank enclosing the lower portion of the travelling grate and
containing a fluid seal rising to a height submerging the lower edge of said end-
wall of the furnace, whereby a sealed passage-way is provided for access to the
tank-space below the grate for removal of debris from the grate, substantially as
described.
17. In a furnace, the combination with the ignition-table and means for supplying
fuel, to the same, of a travelling grate with its fuel-carrying run in proximity to
the lower side of and set inclined toward said table, and an air-supply underneath
the said fuel-carrying run adjacent to said table whereby the air-blast passing
through the fuel upon the grate is directed toward said ignition table for acting
upon the fuel thereon, substantially as described.
18. In a furnace of the class specified, the combination with the enclosed
furnace-chamber, of an endless travelling-grate forming the floor of said chamber
and set inclined, a water-seal substantially as described, covering the lower end of
the grate, and an inclined air-blast chamber between the runs of the grate and
having its lower end depending into the water-seal, substantially as described and
for the purpose specified.
19. In a furnace of the class specified, the combination of the enclosed furnace-
chamber, and with the ignition-table and the water-seal tank, of the lower forward
shaft, the upper rearward shaft, the grate-carrying wheels on said shafts, the
endless grate carried on said wheels and having its upper and lower runs set
forwardly inclined as described, and the air-blast chamber set between said upper
and lower runs and extending at one end thereof into said water-seal tank,
substantially as described.
20. In a travelling-grate furnace, the combination with the travelling grate, of
a non-aërating ignition-block substantially as described of fire-brick or like
refractory material set above and in close proximity to the grate at the fuel-
receiving end of the furnace-chamber and having its upper surface inclined in
substantial alignment with the angle-of-repose of the fuel, and a fuel-supply set to
deliver the fuel to the grate over the inclined surface of said block, whereby the
in-flowing fuel is subjected in a layer of substantially uniform thickness throughout
its length to treatment preparatory to ignition, substantially as described.
21. In a travelling-grate furnace, the combination with the travelling-grate, of
the non-aërating ignition-block having the inclined upper surface and terminating
abruptly at its inner side with a falling-wall extending downwardly into close
proximity to the grate, means for supplying fuel to the grate in a descending layer
over said block, and means for blowing the fuel on the grate contiguous to said
wall, substantially as described and for the purpose specified..
22. In a furnace of the class specified, the combination with the travelling grate,
and with the non-aërating ignition-block B having the inclined upper surface and
the falling-wall in close proximity to the grate, at the fuel-receiving end of the
furnace-chamber, of means for supplying fuel in a relatively thin layer over said
ignition-block to the grate, a reverberatory arch set over the furnace-chamber in
position for reflecting the heat thereof upon the fuel-layer upon said block, and
means for blowing the fuel on the grate contiguous to said falling-wall, whereby
the fuel is treated by simultaneous heating from above and below, is mixed and

page_text: re-formed into a relatively thick layer on the grate, and is there ignited,
substantially as described.
23. In a furnace, the combination with a travelling grate, and with means for
supplying air to the grate, of a multiplicity of fuel-supplying apparatuses sub-
stantially as described in position and arranged for delivering successive supplies
of fuel to the grate at successive points in the length thereof, substantially as
described.
24. In a furnace, the combination with a travelling grate and a fuel-supply
therefor, and with means for supplying air to the grate, of a second fuel-supply in
position for delivering fuel to the grate at a point beyond the normal ignition-line
of the fuel first supplied, substantially as and for the purpose set forth.
25. In a furnace, the combination with a travelling grate and the first fuel-
supply therefor, of the second fuel-supply located above the grate in advance of
the first fuel-supply, a feed-wheel for delivering the second supply of fuel to the
furnace, and means for actuating the feed-wheel and the travelling grate,
substantially as described.
26. In a furnace, the combination with a travelling grate, of a primary and
secondary fuel-supply set one in advance of the other for delivering primary and
secondary layers of fuel upon the grate, and a series of variable pressure air-blast
apparatuses underneath the grate, the first of which is located between said fuel-
supplies, and others of which are located in position for blowing the combined
primary and secondary layers of fuel, substantially as described.
27. In a furnace plant of the class specified, the combination with a travelling-
grate furnace having an air-blast apparatus and having driving apparatus for
actuating the grate, of a blowing-machine connected with the air-supply apparatus,
a mechanism actuator connected with and actuating both the blowing machine_and
the said driving-apparatus, and means for regulating and varying the speed of the
mechanism-actuator, whereby proportionate working movements are imparted to
the blowing-machine and the travelling grate, substantially as described.
28. In a furnace plant, the combination with a travelling grate furnace having
an air-supply apparatus consisting of successive air-blast chambers, of driving
apparatus for actuating the travelling grate of the furnace, a blowing-machine
connected with and supplying the several air-blast chambers, means for inde-
pendently regulating the air-pressures in said chambers, respectively, and a
mechanism-actuator connected with and actuating both the blowing-machine and
the grate-driving apparatus, substantially as described and for the purpose
specified.
29. In a plant of the class specified, the combination with the travelling-grate
furnace, and its successive variable-pressure air-blast chambers, and with driving
apparatus for the travelling grate, of a steam-boiler in position to be heated by the
furnace, a blowing-machine in communication with the air-blast chambers, one
steam engine in communication with the boiler and in operative connection with
both the blowing-machine and the grate-driving apparatus, and means for
regulating the admission of steam to the engine for varying the speed of the same,
substantially as described and for the purpose specified.
Dated this 19th dox of December 1802
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.