Improvements in or connected with Mechanical Stokers.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in or connected with Mechanical Stokers.
We, JAMES JONES MELDRUM, THOMAS FREDERICK MELDRUM, JOHN WESLEY MEL-
DRUM and FRED CLAYTON, all of Atlantic Works, City Road, Manchester, in the
County of Lancaster, Engineers, do hereby declare the nature of this invention
to be as follows:-
This invention has reference to mechanical stokers, that is to apparatus and
means for feeding solid fuel to, and burning it in, furnaces of steam generators,
and other plant or apparatus in which fuel is similarly burned; and the invention
has for its object, primarily, to provide a mechanical stoking apparatus, wherein
the air used in the combustion of the fuel is artificially supplied that is forced
through the fuel; which shall be advantageous and effective and of a simple
construction, and offering, substantially, no practical objectionable features; to
provide certain specific improvements, hereinafter described in mechanical coking
stokers; and generally, to improve the construction of mechanical coking stokers
at various points and parts, and the mode of effecting and carrying on the actions
of combustion.
It is, however, to be understood, that certain novel characteristics of the several
combinations or constructions hereinafter described, where applicable, are to be
taken as being equally applicable for use in connection with sprinkler, or other
kinds of types of mechanical stokers, as well as those of the " coking
kind or
type. But, for convenience and simplicity of description, all the main novel
characteristics and combinations or improvements under the invention will be
specified as combined together in a coking mechanical stoker, employing forced
draught.
A complete mechanical stoker or apparatus comprising, in combination, all the
main features or characteristics of the invention, as applied to a steam generator,
consists as follows: At the upper part, there is provided a hopper for receiving
and holding the fuel, such as small coal, or coke, or anthracite, and from which
the fuel is supplied to a positive feeding device, as a plunger or piston. Below
the level of this device are the coking parts, inlets for air, and doors by which
access is had from outside to them; then, below the level of these, comes an air
chest or box, which encloses or covers the ordinary front opening to the ashpit
below by the grate bars, and by which, air, supplied to the ashpit, under a pressure
above that of the atmosphere is retained, and through which a shaft for mechanically
moving the fire grate bars passes, and with the sides of which it makes a suffi-
ciently air tight joint at the points where it passes through them. In the case
of the steam generator being of the Lancashire type, or, for present purposes, of
an equivalent type, these parts will be in duplicate, arranged side by side, and
carried upon a main frame plate fitting over, and attached to, the front of the
steam generator; and the shafts for working the grate bars, and the fuel feeding
devices, will be operated by a single actuating mechanism at one side; the grate

page_text: bar operating shaft being preferably supported at each end, and in the middle,
where it is coupled together, as hereafter described.
"
First, with regard to the means and parts for supplying the air under pressure
to the furnaces, and the construction of the parts at the front of the apparatus
by which this air is introduced, there is, in the case of a coking stoker used in
connection with a steam generator or analogous furnaces, in the front of the ash-
pit, a box or case having at the upper part a detachable lid or cover, and to the
bottom or sides of which (or both) the discharge ends of steam jet air blowers-
say of the
Meldrum" type are attached; while, in the front, a door (which
conveniently may be of the type commonly used in connection with the Meldrum
furnaces) is provided, and through it, ashes &c., can be removed directly there-
from, it being disposed opposite the lower part of the ashpit. Above this door
there are hand doors of a similar nature, for inspecting or gaining access to the
upper part of the box, and the shaft which works the bars, and the ends of the
bars worked by the shaft or cams thereon.
:
The detachable cover or lid of this box is suitably fastened by bolts through
its flange, or the like, to a flange on the body. In its upper part openings are
provided for conveying air through suitable conduits to the front of the grate and
upper part of the furnace, as hereafter described, the conduit being fixed upon the
lid and to the furnace front.
Extending down at either side from the upper edge of the box, there are slots
through which the cam shafts for operating the bars are placed in or taken from
the box, and the joint between the shaft and the box, ie, the filling up of these
slots or gaps and filling pieces employed are as follows:-
The shaft is preferably rectangular or polysided in cross section, and, at those
parts where it passes through the box sides, it has a collar fitted on it; the collar
being cylindrical externally, and of the same shape as the shaft internally.
This collar works in a neck, formed partly by a semi-circular bottom of the slots
or gaps, whilst the upper half is provided by the lower half of the filling up piece.
Each filling up piece is in the form of a slide, fitting in position in the box
sides with corresponding side bars in the edges of the slots in the box, and having
a flange on the top, corresponding with the flange on the box, and by which it is
fastened to the box lid or cover. On the inside of the box is a flange at each side,
while outside is a bridge piece through which a bolt on the filling up block
passes, and by means of which the flanges on the inside are drawn up against the
inside of the box to make an air tight joint. On the outside of the shaft sleeves,
a loose collar is fitted, which, in action, is made to bear closely against the edges
of the necks formed by the box and filling up blocks, so as to help to make an
air tight joint.
These parts do not serve to carry the shaft or take the thrust of same, the whole
of this being taken, and the shaft carried, by separate bearings on the frame out-
side the box. Brackets are provided on the corners or the sides of the boxes which
carry the bearings at the outer ends, and also, in the case of a double furnace
arrangement, the centre of the cam shaft.
In the case where one line of shafting serves to work two sets of stokers side
by side, the shafting is not continuous, and the abutting ends of the two bars
between the stokers are connected together and supported by a single bearing,
the connection being effected by a sleeve, externally cylindrical, which fits over
their ends, and works (i.c. revolves) in the bearing, and the sleeve and shafts are
fixed as regards longitudinal movement by collars, which fit over the ends of the
coupling sleeve, or a collar and flange on the sleeve, and these are fixed by pins
passed through the sleeve collars and shaft.
In some cases, this central bearing, and the end bearings, are adjustable verti-
cally by adjusting screws, which pass through or screw in bosses on the frame of
the apparatus, by the screwing up or down of which the height of the shaft bear-
ings can be set; they being held on the frame plate by holding on bolts, slots being
provided in the one or the other to permit of the vertical adjustment.

page_text: In one case the discharge ends of the. air blowers are fastened into the bottom
plate of the air box, and in such cases a hinged flap or the like is in some cases
provided within the box, which, when folded down, covers these blower mouths;
and so the clinker and ash drawn from the ashpit is prevented from falling down
them, and they therefore serve at such time as a false floor over the mouths. At
other times, when the box is shut up, the flap or valve is moved up about its hinge
and lies against the front of the box.
In the lower part of the box, in the case of the application of the invention to
internal furnaces, such as are used in the Lancashire, Cornish and Marine types,
and the like, there is an internally fitting part which fits all round the lower
front edge of the furnace, in such a manner, that water condensed from the steam
supplied by the blowers, cannot get or lodge in between these fittings and the
front of the steam generator, but will pass from the ashpit, being guided by this
plate or projecting part, into the bottom of the air boxes. By this means corro-
sion of the generator plates from such causes is obviated.
In a coking stoker, some of the air delivered into this box is conveyed up through
openings in the cover or lid, as described, to a point above the level of the bars
or fuel bearers; and this takes place, preferably, in three places, namely, in the
middle, where a central chest is provided under the fuel feeding devices, and on
either side of same. In one arrangement or construction, this central chest is
carried on hinges as a door, and. has, inside, a ribbed or openwork metal plate,
which stands inwards of the frame and keeps the fuel, delivered from the feeding
devices above, a certain distance away from it, and serves as a protecting device
to it; and air passes from the air box below into this chest, and through this grid
or plate, into and through the fuel which is piled up in front of it, and is resting
upon the coking plate.
This hollow hinged chest, in one construction, has on the back, a door, which,
when open, enables the fire upon the coking plate and fire bars to be stirred or raked
from the front, whereas, when the whole hollow chest with the grid or protecting
plate, &c., is opened, access is had bodily to the interior of the furnace above the
bars, for cleaning, manipulation, &c.
The above hinged air chest has a tooled face where it fits up against the front
stoker frame, and this face fits upon another tooled face formed partly, namely,
at the ends and above, on the stoker main frame plate, and partly, that is at the
lower part, by an upwardly projecting flange or rib provided along the front of
the inner edge of the air box cover or lid, and fitting into a corresponding part,
that is recess, in the lower edge of the front frame.
In connection with the front lower part of the central air chest, there are inclined
projecting fingers, whilst upon or in connection with the front of the coking plate,
which fits or lies over a part of the back of the air box, there is a valve, the inclined
projection being arranged so that when the door is closed, this valve will be raised
or opened, admitting air to the under protecting plate or grid plate of the central
air chest; while, on the other hand, when the door is opened the valve is closed.
The side air conduits, extending up from the air box cover or lid to the front
frame, consist of chests or boxes, having preferably, doors at their back; while
openings in the form of grids are provided in the front frame, as hereafter
described, to admit the air they convey to the fuel upon the coking plate. The
doors in these conduits enable access to be had for stirring or cleaning the fire
or fuel on the dead plate at either side of the furnace.
The above sets forth generally all the main characteristics of the invention as
regards the supply of primary air to the ashpit, and to the fuel being coked upon
the coking plate in the front of the furnace, and also as regards the air box, and
those parts directly connected with it. With regard, however, to the air which is
supplied from this box upwards, at points above the level of the fire bars, and the
disposal and use of the air, and the manner of its introduction and combustion,
this will now be described.
Within the main front frame, enclosing the upper part of the furnace, a special

page_text: detachable false front is provided; and this front is attached to the main frame,
and is disposed a certain distance away from it, the space between the two being
adapted to serve as an air conduit or air conduits.
Under one arrangement, the false front is made in halves, and each half is pro-
vided with gridded parts, or apertures, in the form of short tubes, the ends of which
abut against the inside of the furnace front, and are held up thereto by a central
or side bolt; while the front frame itself is also equivalently provided with slots
which correspond with the former slots or apertures. A through way is provided
direct from the side air conduits above specified, into the fuel which will be resting
on or piled up against the face of the false front, and under the process of coking.
In a modification of this construction of side air supply inlets, in the front
frame proper, loose or detachable blocks or plates (with apertures corresponding
with those of the false front), are provided, and secured by central or side bolts to
the main front frame.
In some cases the side air conduits consist of simple closed boxes, bolted to the
main frame and lid, (in lieu of having doors as above described), with openings
at their bottoms.
In a further modification regarding the supply of air to the front, closed boxes
or chambers are provided on the false fronts, the portion of which comes next the
fire are perforated with slots. To form these chambers, the false front is provided
with ledges, the edges of which bear upon the inside of the main front frame,
and form the sides thereof. In this case also the false face and inner air chests
thereof may be secured to the front frame from the outside by stud bolts and
nuts.
In some cases the openings in the false front are made of greater area than
those in the main front frame; whilst in other cases, they are of the same area.
In most cases round the edge of the false front there is a rib, the edge of which
is turned outwards, which serves to give the plate greater rigidity, and at the
upper part of these false fronts, pieces on the inside, in the form of short ribs, are
provided. In some constructions, as hereafter specified, the false front is provided
on the inside with special ribs or flanges so as to form conduits or passages for
the supply of air from the air box below to different parts above it, as specified.
By this detachable false front in connection with the main front frame, a part
is provided, which, when it has become burnt, can be readily removed and renewed,
thus preventing the burning and effecting the saving of the furnace front proper;
and, at the same time serving as air conduits for conveying air-in the case of a
coking stove through the fuel piled up against it at the front, and also for
supplying air in some cases to a point above the fuel.
In some cases, a grid block, with a flange on the outside, is let into the furnace
front and secured by a stud bolt and nut, and it, the false front-in which the stud
is fixed, and the front frame, are all held and bound together; also the grid may
be provided with a valve, as a grid, or hit and miss valve. According to a further
part or modification under this invention, the furnace front frame, and a false
front at the upper part of the furnace above the level of the bars, together are
adapted to form air conduits at the sides, the lower ends of which communicate
with the air box below, in which the air is supplied under pressure; and these
conduits extend up to a point at the upper part of the furnace above the fuel
feeding device, at which point the front face is provided with apertures, such as
slots, whereby the air under pressure from the ashpit box is delivered as secondary
air above the fuel. According to one arrangement a sliding grid or perforated
valve is employed in connection with the air apertures referred to, so that by
sliding this valve to and fro, or up and down, the amount of air supplied can be
regulated or entirely cut off. As a substitute for this valve, in some cases, a
damper valve or a butterfly valve, is employed to operate across the air conduit,
by the operation of which, the air conduits can be more or less closed and the
air supply regulated; or again, a suitable hinged flap or butterfly valve could be
provided in the plate at the level of the dead plate or fire bars, or in the lid of

page_text: the air box. The grid in the false front referred to, in one construction, may be
held in place by a stud and nut in the manner employed for holding the side air
grids or apertures above specified; or it may be provided at each side with inclined
lugs in the form of wedges, which fit in corresponding catches or lugs on the
false front, for holding it in position.
As a modification of the construction just described, by which air is conveyed
from the air box to the upper part of the furnace front, the air conduits may be
cast in the front frame proper, and extend up within the false front from side
chambers connected with the air box, to a point above the fuel feeding device, at
which point, it is provided with a grid or openings, and a suitable regulating
valve, such as specified.
A further part of this invention consists of a mode or means of effecting the
equalisation of the rate of the forward feeding of fuel supplied to mechanical
coking stokers at each or every point across the whole of the furnace. In coking
mechanical stokers, the fuel, such as small or granulated coal, coke, or other com-
bustible, is supplied, generally pushed, by a plunger or piston into the upper part
of the front end of the furnace, the width of this feeding device being generally con-
siderably less than that of the furnace. The tendency therefore, is for the pile of fuel
resting upon the coking plate directly in front of the device to become greatest
at the centre of the furnace, and less in thickness towards the edges; with the
result that more fuel is generally pushed on to the moving bars at and near the
centre than those at the sides, and therefore the rate of feed of fuel, and combustion
at the different parts of the grate, transversely, is not equal; and hence, ordinarily,
the furnace does not operate with, and produce the fullest efficiency. According
to the present invention the equalisation of feed of fuel, and its combustion, for
the whole width of the grate is effected by so arranging the coking parts, that the
edge of the coking plate, constituting the point of take-off of fuel by the bars in
moving, shall be practically coincident with the natural outer lower edge of the
pile as it distributes itself on being pushed in by the plunger or feeder on to the
coking plate. Under the conditions named, the lower edge of this pile will be
the greatest distance from the furnace front plate at the centre, and the least at
the edges near the sides of the furnace, and the edge of the coking plate on which the
pile rests is made to approximately correspond with the edge of this pile. The
coking plate, therefore, according to this invention will be of a varying depth
inwards, being greatest at the front of the inside of the furnace, and diminishing
towards the edges. This diminishing edge is in some cases a curved line; in
others it consists of two straight inclines, extending from the centre to each side
or corner while in another form the edge, whether generally curved or in straight
lines, is serrated. In the centre (that is the part directly under the centre grid
or baffle which keeps the fuel away from the central air conduit, and tends to
distribute it across the furnace) the coking plate projects towards the front, and.
is in some cases provided with an air valve or damper for admitting more or
less air from below to this part of the fuel on the plate. In another case, however,
this part of the plate may be merely gridded. The body of the coking plate is
provided with slots forming a grid, by which air is admitted from below; which
air, together with that supplied through the vertical grids or openings in the
false front, serves to effect the coking action of the fuel upon the plate.
The bars of the grate, slide alternately to and fro longitudinally under this
plate, their front ends being disposed in the air box, and worked by cams from the
cam shaft above specified.
According to a further part of this invention, in connection with mechanical
stokers, we employ, in combination with the moving pars, permanent or non-
moving adjustable compound bars at the side. For the full length of the grate
on either side, there is a main longitudinal bar, which side bars are arranged
parallel in the furnace, between which parallel bars the moving bars work: while
between these bars, and the sides of the furnace, there are two other bars, one of
which has tongues or lateral projections, whilst the other is of duplex form, with

page_text: slots in it; and within these slots the said tongues or projections fit and work. The
upper and under parts of the slotted bars are connected together by blocks or
distance pieces. These two inner bars rest on projecting brackets on the inside
of the main longitudinal bars, and they are retained longitudinally thereon, by
projections, which come up against the sides of the said brackets. Between these
two inter-connected bars, distance blocks or pieces are introduced, so that when
the required adjustment has been made to produce the parallel arrangement
between the two main inner bars, the bars are held in position. These packing
pieces are supported and held in position by projecting parts, which, rest upon
the tongues or sides or other parts of the adjustable bars. In connection with
these adjustable bars, there are also used, in some cases, plugs or pieces to fill up
spaces in the furnace sides, such as spaces produced by the seams, or special rings,
and the like, employed in the furnaces; these projecting parts being provided with
tongues which fit in a slot or aperture along the inside of the inner adjustable bar,
which thereby supports them, they being adapted to slide or fit in same, at any
point longitudinally.
In connection with the back end of the ashpit of a furnace, a special door and
door frame is provided, and the back end of the ashpit at the end of the grate is
positively closed by such door frame or plate. Thus the ashes and unburnt
matters are discharged by the bars over the end of the grate behind the door and
frame. The door is mounted upon a horizontal hinge in the upper part of the
door frame, and is operated by a wheel or barrel and a chain or the like, wrapped
round it, the wrapping round being carried to such an extent that the full radius
of leverage for opening the door exists for the whole opening stroke. This chain
or cord for operating the door is also preferably carried under a projection at the
lower part of the side of the door, so that it acts also upon the lower end of the
door in opening. In another case the door is operated from a lever, which is so
arranged in relation to the door, that it lies behind the face of the door, so that
when the door is quite up and open, at the end of the stroke, considerable leverage
still exists. The lever is worked by a chain or cord which extends from the door
to the front portion of the ashpit. In one form, the front of the door frame on
which the door rests when closed, projects from the plate inwards, and is provided
with an inclined face, in contact with which the door comes, and on which it would
rest, when closed; while the door itself is supported by lugs or brackets at each
side and hinge pins, on the ends of which the barrels or bosses of the door, at each
side would fit. When this door is closed the air is locked in the ashpit, and all
has to pass up through the grate bars; and when the ashes delivered by the bars
beyond it are to be removed, the door is opened from the front by the cord or
chain.
With regard to the fuel feeder, that is the plunger or piston by which the fuel
is delivered into the furnace, this in one arrangement is supported mainly by lugs
of wedge form, at its side, and corresponding wedge shaped catches on the front
frame, in which they rest, by which the weight of the parts presses the whole
device up to the front frame; and it may be additionally secured by studs or screw
bolts above.
In connection with the mechanical stoker of the kind herein referred to, wherein
a vertical shaft operates the horizontal shaft of the fuel feeder, and the bar moving
shaft mechanism, this vertical shaft is supported from the frame by a bracket,
which is cup-shaped in its body, and has an adjustable footstep at its outer end,
in which the lower end of the actuating shaft is supported, while it is fixed at
the other end to the main front frame. Thus the bracket serves the double purpose
of supporting the said shaft at its end, and as an oil catcher for the oil which falls
from the mechanism above. The adjustment of the footstep is effected by means
of a screw in its bottom; or, in lieu of this, a spring may be used to support the
shaft and take the wear.
In some cases, there is combined with the air supply parts of furnaces, such as
described, means for heating the air delivered to the air box and furnace, prior

page_text: to such delivery. In the application to Lancashire, and other analogous steam
generators, this air is heated by the waste gases; namely, the gases from the side
Hlues of the generator are passed through a continuous air regenerator, placed at
the back of the steam generator, and heat the air heating conduits or parts of the
regenerator; and the air is passed through these conduits, or over these heated
surfaces, and heated, and then, in this condition, is led from the regenerator to
the blower or blowers, through conduits, below the side flues, and on the level of
the bottom flue.
The general improvements under this invention have been described as applied,
chiefly, in combination in a mechanical stoking apparatus in which forced draught
is employed, and in which the stoking parts proper are of the coking type; and
they have also been described as used, mainly, in connection with cylindrical
furnaces, such as are ordinarily used in Lancashire, Cornish, Scotch, and analogous
kinds of steam generators; but it is to be understood, that while they are advan-
tageously serviceable in combination, yet, separately, they, or some of them, are
capable of being used with advantage, either by themselves, or in combination
in mechanical stokers of other or different types, and employing other modes for
supplying the air for the combustion of the fuel; and also in connection with
other kinds of furnaces. And, when employed in connection with furnaces which
differ in form from those referred to, the parts, or some of them, will be modified,
or applied in different modified manners, to suit the varying conditions of appli-
cation. And it is to be stated that, generally, in the carrying out or application
of the invention, the various parts will necessarily be modified as to form or con-
struction to meet various requirements, or special cases.
CHEESBROUGH & ROYSTON,
Applicant's Patent Agents, 15, Water Street, Liverpool.
Improvements in or connected with Mechanical Stokers.
We, JAMES JONES MELDRUM, THOMAS FREDERICK MELDRUM, JOHN WESLEY MEL-
DRUM and FRED CLAYTON, all of Atlantic Works, City Road, Manchester, in the
County of Lancaster, Engineers, 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:-
This invention has reference to mechanical stokers, that is, to apparatus and
means for feeding solid fuel to, and burning it in, furnaces of steam generators,
and other plant or apparatus in which fuel is similarly burned; and the invention
has for its object, primarily, to provide a mechanical stoking apparatus, wherein
the air used in the combustion of the fuel is artificially supplied-that is, forced
through the fuel; which shall be advantageous and effective, and of a simple
construction; and offering, substantially, no practical objectionable features; to
provide certain specific improvements, hereafter described, in mechanical coking
stokers; and, generally, to improve the construction of mechanical coking stokers
at various points and parts, and the mode of effecting and carrying on the actions
of combustion.
It is, however, to be understood, that certain novel characteristics of the several
combinations or constructions hereinafter described, where applicable, are to be
taken as being equally applicable for use in connection with sprinkler, or other
kinds of types of mechanical stokers, as well as those of the "coking" kind or
type. But for convenience and simplicity of description, all the main novel

page_text: characteristics and combinations or improvements under the invention will be
specified as combined together in a coking mechanical stoker, employing forced
draught.
The invention will be chiefly described in connection with, and by the aid of
the drawings accompanying this specification, which shew, generally, a mechanical
stoking apparatus applied to a twin or double circular furnace of the coking type.
In the drawings, Figure 1 shews a stoker according to this invention, in outside
elevation, applied to two circular furnaces, say of a double steam generator, with
the outer parts on one side removed; Figure 2 is a longitudinal sectional elevation,
shewing the apparatus; and Figure 3 is an outside elevation of same. Figure 4
is a section, shewing a detail, taken at the line A A Figure 2.
Figures 5 and 6 are sectional elevation, and end view, of side supplemental air
supply devices, hereafter described; and Figures 7 and 8, and 9 and 10, are,
respectively, sectional elevation, and outside view, and inside view, and sectional
plan, shewing modifications of this air supply device.
Figure 11 is a sectional elevation, taken at BB Figure 12, and Figure 12 is
an outside elevation, partly in section, shewing a further modification connected
with the supply of air to the furnace above the fuel.
Figure 13 shews a coking plate according to this invention; and Figures 14
and 15 are plar and cross section, respectively, shewing a modification of coking
plate. Figures 16 and 17 are end view, and elevation, shewing the construction
connected with the end of the ashpit below the grate bars; and Figure 18 shews,
in elevation, a modification of same. Figures 19, 20 and 21, are plan, side ele-
vation, and cross section, respectively, shewing the construction and arrange-
ment of parts connected with the grate.
The complete mechanical stoker or apparatus, as applied to a steam generator,
comprises the following main characteristics, or parts in combination, namely:
A hopper a at the upper part, for receiving and holding the fuel, such as small
coal, coke, or anthracite, and from which it the fuel-is supplied to the furnace.
Directly under this hopper, is the positive feeding plunger or ram c, horizontally
arranged, and vibrating forwards and backwards, about a centre. Then below
this, are the coking parts, doors for gaining access to the fuel at the front, and
supplemental side air supply devices; namely, a coking plate i, main doorway o,
and door p, and side air supply devices c. Then below these again, comes an
air chest or box u enclosing the front of the ashpit a, and also the fire-bar ends,
and mechanism for operating them; while again, on the underside of these
boxes u, are inverted steam jet blowers w, their discharge mouths or ends being
connected to the bottom plate of the box.
By the blowers w, air is supplied to the box u and the ashpit a of the furnace,
and is maintained therein at a pressure above that of the atmosphere; and from
this box air is supplied to the back of the fuel resting on the coking plate i, and
also to the space above the fuel, in the hopper a. The air supplied to the back
of the fuel on the coking plate i, is for the purpose of assisting the combustion of
fuel, and a rapid coking action; and that supplied in the hopper a, above the
fuel, is for obviating the burning back of the fuel from the furnace up into the
hopper. Generally speaking, the above parts specify all the main character-
istics concerned under the invention, connected with the supply, of air.
The apparatus shewn is of duplex kind, arranged and adapted for use in con-
nection with a double furnace steam generator, or other apparatus to be heated,
the parts being in duplicate, and arranged side by side, as shewn; and these parts
are carried by main frames or plates b, attached to the front plate of the steam
generator, or other apparatus in connection with which the apparatus is used.
First, with regard to the means and parts for supplying the air under pressure
to the ashpits and furnaces, and the construction of the parts at the front of the
apparatus, the box u, to which air is supplied by the blowers w, is provided with
a lid or cover u¹, which is fastened by bolts to the external flange, u³, extending
all around the top edge of the box u, the box itself being secured to the front

page_text: plate or frame b, by flanges u³. Of course, the part of the box which comes next
the ashpit of the furnace, is open to the ashpit; while in the front of the box,
opposite the ashpit, there is a detachable hand door u, supported by lugs us at
each side, by which, when it is removed, direct access to the ashpit through the
box u is obtained. At a higher level in the front of the box, similar doors us are
provided, by which access to the cam shaft and cams for working the bars,
can be had, for inspection, lubricating, and other purposes, when required.
The inverted blowers w, are of the steam jet type, and are secured by their
discharge mouths to the bottom plate of the box u; while their heads (pass
through the ordinary footplate below, from which the furnaces are worked, and
are enclosed in a box or chamber below it. By this arrangement and construction,
the noise created by jet blowers is restricted to the chamber in which their heads
are placed and enclosed, and is rendered unobjectionable to those outside. In
connection with these blowers, within the box u, there is a flap door u, hinged
at us, which is adapted to fold down, and cover the mouths of the blowers w,
when the door u is off, and ashes, etcetera, are being withdrawn from the ashpit;
thereby preventing such ashes, etcetera, falling down the blowers. Also, on
the lower part of the box, in cases where the invention is applied to the furnaces
of internally fired steam generators, there is an angle plate u, which fits over the
edge of the front plate y of the steam generator, at the bottom of the ashpit;
thereby preventing the access of water or moisture from the ashpit to the front
plate, so preserving the rivetting and plate against corrosion, which might
otherwise happen.
The shaft which carries the cams for working the firebars, passes through the
box u, and is designated t. This shaft is hexagonal in section, and where it
passes through the sides of this box u, the sides are gapped from the flange down-
wards, and the shaft is provided with a sleeve t¹, circular on the outside. This
sleeve works partly in a half bearing, formed by the bottom of the gap, and
partly, viz., at the upper half-in a half bearing formed by the lower end of the
plate 3, which fills this gap; while outside these parts, there is a collar t³, larger
in diameter than t¹, fixed on the shaft t, which is adjusted up to the outside
edges of the bosses t¹, formed on the bearing parts, in which the sleeve works.
By these means, an air tight joint between this bearing and the shaft, and parts
carried by it, is made. The filling plate is held in position by a flange at its
upper edge, which is bolted to the cover u¹, with which it makes an air tight joint;
while at its sides, it is provided internally with vertical flanges which bear
upon the inner surfaces of the side plates of the box u, up to which they are drawn
by a stud bolt and nut to, placed in t2, and passing through a bridge bar t, the ends
of which rest upon the sides of the box u, outside. The lid of the box is provided
at each side with openings at u10; and projecting inwards of the inner edge of
this cover, and also, above the surface thereof, is a rib or ledge, which works in
connection with the door opening o in the frame plate b, as hereafter described.
Referring now to the fuel feeding means, and parts connected with the com-
bustion of fuel, the fuel is contained in the closed and air tight hopper a, which
has a close fitting door a¹ on the upper part; and the upper part of which above
the fuel in it, communicates with the air box u by a pipe a². By this air, the
direction of movement of air in the hopper, and through the fuel, will be towards
the opening through which the fuel passes into the furnace, and all tendency of
burning back of the fuel up into the hopper a, owing to the use of forced or
plus pressure draught employed, is obviated. In the case shewn, the air is
conducted to the upper corner of the hopper, by a simple external pipe; but it may
be carried up by a special passage cast or formed in the frame b at the back of
the hopper a; and a guard a³ may be used about or in front of the entrance of
the pipe into the hopper, to prevent the fuel entering it. The air tight joint
between the hopper a and its door a¹, is effected by a rib a' on a, and a channel
formed by flanges as all round the edge of the lid a, and having an asbestos,
indiarubber, or other suitable strip as within it, which comes upon the edge of

page_text: the flange a, and makes an air tight' joint with it'; or the door and seat may
be faced. To adjust the door properly, the door hinges at each side should be
adjustable vertically.
1
The feeding ram or plunger c is disposed directly under the open bottom of the
hopper a, and is arranged and works in a casing attached to the frame b.. The
hopper rests on the upper part of the casing c¹, and the casing itself is secured
to b, by means of wedge shaped lugs c², formed upon it, at each side, and fitting
into corresponding inclined catches c³ formed on b. A further support and attach-
ment of the case to the plate b, is effected by screw studs, which pass through
the upper part of the lugs 2, and screw in to b. By this construction, and mode
of attachment, the whole fuel feeding device, and the hopper, can readily be
removed, and replaced in position when desired. The plunger or ram c is mounted
on a shaft c, passing through the lower part of the casing c¹, and supported in
the end plates thereof. The casing c is open at 6, to allow of any fuel, that
may get behind it, to escape. The front of the ram, however, next the furnace,
fills the casing between the bottom plate and the upper part. The ram c is
vibrated by suitable gearing through the shaft c5, and, at the backward vibration
or swing, fuel falls down in front of it, from the hopper; and then, when it
moves forward, it presses the fuel forward, through the opening b₁ in the plate b,
onto the coking plate i hereafter described. This opening b₁, is, practically, of
the full depth of the plunger; the front of the casing c¹ is also open for the full
depth of the plunger. On either side of this opening, the detachable shield plates
hereafter described, are disposed.
Within the frame plate b, and in front of the door opening o, there is a gridded
shield p¹. This shield is formed on, or attached to the inside of the door p; and
the slots in it are vertically arranged. This shield," as shewn, extends' inwards of
the furnace, and in an inclined direction downwards; and is open below. Through
this open part, air from the box u is admitted to the space within it; and this
air passes through the slots in the shield, and fuel resting in front of it, and
assists in the combustion of the fresh fuel, and effects a rapid coking of it. The
shield also protects the door p by keeping the fuel off it, and guides the fuel
on to the coking plate i below.
The door is of special construction, as shewn in the drawings, that is to say,
there are two doors, a main door p, which consists really of a hollow core or
frame, hinged at 22 to the plate b, and a secondary door p³, hinged at 74 on the
door 2, the shield or grid p¹ being formed on, or connected to the inside of the
main door p. The main door has an ordinary latch fastening, to engage with
a catch on the plate 6; and the secondary door 23 has a latch engaging with a
catch on the door p. The inner face of the door ? closes the opening o all round.
The edge of this opening, which constitutes a seat, against which the inner edge
of the door comes, is the edge of the plate b at the sides and top of the opening o;
whilst the lower part of the opening is formed by the inwardly projecting rib ul
on the cover u¹ of the box u, which exactly fits in the space across the bottom
of the opening o, and fills it. The plate b, as shewn, does not extend down below
the opening and the bottom of the cover u", except at each side, where it is
carried down in the form of horns 63, which carry the brackets or bearing for
supporting the cam shaft t. The face of the door p, which comes up against the
seat constituted by the edge of the plate 6 around the space o, and the rib ull,
may be tooled, as may also the seat, to effect an air tight joint. The effect of this
construction is, that by means of the door 2³, the fire in front, resting upon the
coking plate i, can be seen by opening it, without disturbing the fire; whilst, by
opening the main door p, access to the space above the coking plate and fire bars,
and the fire on them, can be had, and the fire worked, and other operations per-
formed; while, at the same time, by the space between p¹ and the,hollow door.7,
the temperature of this door is kept at such a point as will prevent it or the plate b,
baing damaged by the fire.
וי
11

page_text: In some cases, the hollow door will have a permanent back plate instead of the
door p³.
In the modification shewn in Figures 11 and 12, a construction is shewn by
which air from the box is conducted to the upper part of the furnace front,
and admitted to the furnace above the fuel. The modified construction consists
in providing or forming in the front frame plate b, outside the other openings
specified for air and fuel introduction, a conduit h communicating with the box u,
by means of chambers on each side of the box u. At the upper part of the
conduit h, and nearly on a level with the crown of the furnace, openings are
provided, and in the construction shewn, these openings are in a separate plate h³,
secured on the inside of the conduit by a central bolt h passing through the front
plate 6, or by lugs 5 on either side, fitting into suitable catches on the inside
surface of the conduit h. The air to these apertures, is controlled by valves_76
of the butterfly type, or any other suitable type, or a sliding grid valve on the
plate h. The chamber h¹ communicates at the said side with the box u, and
above with the conduit by the openings, as shewn.
Referring now to the coking plate i, according to this invention, this is so
formed, that the equalization of the rate of the forward feeding of fuel in
mechanical coking stokers, at every point across the whole of the furnace, is
accomplished. This plate i is shewn in detail in Figures 13, 14, and 15, and
its chief characteristic consists in making it longest at the centre, and decreasing
in length towards each side, being shortest at the furnace sides. The result is,
that the edge of the coking plate, and the natural lower edge of the pile of fuel
on it, as it distributes itself on being pushed in to the furnace by the plunger or
feeder, are practically coincident; and, therefore, the rate of supply of fuel from
the pile, at the point of take off of fuel by the bars, will be substantially equal
along the whole width of the plate and furnace. The forward edge of the plate i
from the centre to the sides, may be curved, serrated, or rectilinear. In Figures 13
and 14, it is shewn slightly curved.
The inward portion i¹ of the plate i, projects forwards, opposite the doorway o,
and is provided, at its leading or front edge, with a flap hinged at the corners
of the back edge, in the plate i at 3. When the door p is closed, the front edge
of the flap valve 2 is raised by a projection 26 on the lower edge of p, the incline
coming in contact with the underside of 22 in closing the door. This flap valve
is opened, and provides a free opening for air under pressure from the box u to
the space under the shield 7. When the door 7 is opened, 76 leaves the flap 12,
and it closes, and only a small quantity of air passes up from a to the comparatively
small grids in this valve. In the plate i shewn in Figure 13, no flap valve is
provided, and all the air passes up through the larger openings in the part
under the shield p¹. On either side of the doorway o, through which the fuel
enters the furnace, the detachable and renewable plates d, for protecting the
main frame b, are provided. The lower edge of these plates is in about the same
horizontal plane with the lid of the box u, and the lower edge of b, and their
inside edges, next the opening o are carried up vertically; while, on the outside,
they are circular, to correspond with the sides of the circular furnace. These
plates are disposed some distance away from the frame plates b, and are kept in
position in relation to b, by the distance blocks d, or other similar means. They
are also kept in position and drawn up towards b, by stud bolts or the like.
Inside these plates, that is, on the side next the fire, at the outer edge, a rib or
flange is provided as a means of stiffening them. The main function of these
plates is to protect the more important and expensive frame plate b, and prevent
it becoming burnt and destroyed by the fuel being coked, and the heat of the
furnace, and erosive action of the flames; and when, in themselves, they become
burnt and damaged, by simply removing the damaged ones and introducing new
ones, which can be very easily and quickly done, the main frame plates 6 will
remain intact and serviceable for the whole life of the apparatus.
Through these plates, air is supplied to the fuel on the coking plate i at each

page_text: side, by means of the air supply devices e, which convey air from the box u, to
the pile of fuel on i, and resting up against the plates d. In one form, as shewn
in Figures 5 to 8, the devices e consist of boxes or conduits fitting on the cover u¹
of the box u, and upon the face of the plates 6, they being open at the bottom
above the holes u10, and provided with slots or vertical openings el at the back.
The plate bis provided with openings where these devices e fit upon them, and the
air summly devices are provided with extensions e, in the form of short trunks,
which pass through the plate b; while similar extensions, with openings din
them, corresponding with the openings &, are formed on the inside of the plates d,
and these plates and the devices are secured together, and pulled onto the
opposite sides of the plate h, by a central bolt or screw stud e; whilst the bottom
flange of the devices e is secured by bolts or studs onto the cover u¹. The air
under pressure from the box u, passes by way of the openings u10, and the
passages ed, through the pile of fuel in front of them, resting on the coking
plate, and assists in the combustion of fuel on the coking plate, and the coking
of such fuel. In the air supply device e shewn in Figures 5 and 6, the front of
the box is provided with a hinged door e; whereby access to the air openings e¹,
and also the fuel beyond them on the inside of the plate d, is had, and the
fastening bolts e³ can be attended to. In the modified devices shewn in Figures 7
and 8, the air devices e are without doors, and they are drawn up to the plates b
by a stud bolt and nut e secured in the plate d, and passing through e. The air
trunks d on the plates d, rest up against the inside of b, and the air passes from
the box u through the plate d, similarly as in the former case.
In the modification of the side air supply device shewn in Figures 9 and 10, in
sectional plan, and inside clevation, the plate d is provided, internally, with a
continuous flange d*, and with slots or openings d within this flange, whilst the
air device e simply conducts air from the chamber u, throughout the openings in
the plate b, into the space within d**, from which it is distributed through the
fuel in front of the plate, by the gridded openings d².
The fire bars are worked to and fro by cams on the shaft t, in any suitable way;
and the shaft t is revolved by suitable driving mechanism. The shaft t is made
in two lengths for the two furnaces, and is supported in three bearings, one bear-
ings at each end, and a central bearing s in the middle. The shaft represents
a poly-sided figure in cross section, and where it passes through the bearings, it
is provided with externally cylindrical bearing sleeves. The central bearing
supports the two adjacent ends of the two shafts t; and these two shafts are coupled
together. The sleeve at this central bearing, performs two functions, iz., it
acts as a journal for revolving in the bearing si, and also as a coupling. At one
end, it is provided with a flange 3, and through this part it is fastened to the
end of one of the shafts t, by a pin s, and so the coupling is connected to the shaft;
while at the other end a loose collar 5 is provided on the end of s³, and both it,
the sleeve s², and the end of the other shaft t are all secured together by a pin 56.
By this means, this single bearing s¹ serves to support both shafts at the meeting
ends. The sleeves 2 of the end bearing are similar in construction and function
to that just described, except that of the service as a coupling.
The bearings s s¹ are adjustable vertically on, and fixed upon the horns 6³ of
the plates b, the adjustment being effected by the screw studs $8.
In this mechanical stoking furnace, the clinker and residue is delivered from
the moving fire-bars over the end of the grate, and beyond a plate closing the
ashpit ends, and they are removed from this point through a doorway, which is
normally closed by a door, in a plate. This door and its doorway and plate, are
shewn in Figures 16 and 17. In these figures, f is the plate fitting in, and
filling the end of the ashpit below the fire bars at the rear end; f¹ is the doorway
therein, the face of which is inclined, as shewn; and g is the door fitting over
and normally resting on the face of the doorway, and supported by hinge pins g¹
at the upper corners; these pins being supported in bosses on the plate f, and
enter bosses gª on the upper corners of the door g. These door bosses serve as

page_text: pullies, operated by chains 9³, which pass over them, and are fastened to them' by
studs ; and the chains 93 also pass under projecting parts on the lower edge
of the door. By thus arranging and mounting the chains 3 for operating the
doors, and passing them under the lower edges of same, the doors are readily and
more easily operated.
A modified form of door operating means, is shewn in Figure 18, in the closed
and open positions, in which the hinge of the door is provided with a lever g
operated by a chain g³, the lever g being so arranged that when the door g is open,
considerable leverage is offered by the lever g as shewn.
Referring now to Figures 19, 20, and 21, there is shewn in these figures, a special
construction and arrangement of stationary bars or plates used at the sides of
the furnaces employing mechanical stokers with moving fire bars, the stationary
bars or plates being employed to fill up the space between the outer-most moving
bars and the sides of the furnace. The construction consists, in the first place,
of fixed bars k, which are of full length of the grate; the ends of which are held
at the front and back of the furnace. These bars are arranged one on either side
of the moving fire bars, which work up along the plain side of these bars k. Be-
tween these bars k, and the side of the furnace plate, are making up bars, which
are supported by brackets k¹, on the outer side of k. These making up bars, k
comprise bars next the bars k, having upon them, at one side, a number of pro-
jecting tongues l, and projections 12 on their under sides, the vertical faces of
which abut up against the inside surfaces of k¹, and so hold the bars in position,
longitudinally. Then inside the bars 7, and coming next the furnace side, are
third bars m, which, on the side next 1, have slots in them to receive the tongues l¹,
and these bars m are partly supported by these tongues, and partly by the
brackets, and the side of the furnace which they abut on. In the outer edge of
each of the bars m, there is a longitudinal slot, which takes a filling up piece n,
these plates being adapted to fill the triangular spaces existing in furnaces, which
are made up of several cylindrical parts, the ends of which are flanged outwardly
and rivetted together. At these joints, the triangular grooves round the inside
of the furnace are formed. These pieces n can be slid along a slot m¹ in m to
adjust them in the position of these grooves or recesses. When the bars and m
have been fitted in position, the spaces between them can be plugged, by suitable
plugs to keep them at this distance apart.
fi
The general improvements under this invention have been described as applied,
chiefly, in combination in a mechanical stoking apparatus in which forced draught
is employed, and in which the stoking parts proper are of the coking type; and
they have also been described as used, mainly, in connection with cylindrical fur-
'Lancashire,' Cornish,"
naces, such as are ordinarily used in "
Scotch," and
analogous kinds of steam generators; but it is to be understood, that while they
are advantageously serviceable in combination, yet, separately, they, or some of
them, are capable of being used with advantage, either by themselves, or in com-
bination, in mechanical stokers of other or different types, and employing other
modes for supplying the air for the combustion of the fuel; and also in con-
nection with other kinds of furnaces. And, when employed in connection with
furnaces which differ in form from those referred to, the parts, or some of them,
will be modified, or applied in different modified manners, to suit the varying
conditions of application. And it is to be stated that, generally, in the carrying
out or application of the invention, the various parts will necessarily be modified
as to form or construction to meet various requirements, or special cases.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what, we
claim is
1. In a mechanical stoker for furnaces, in which the fuel is coked at the front
end, a fuel feeding device at the upper part of the furnace front, adapted to feed

page_text: fuel on to the front end of the furnace; a box below, enclosing the mouth of the
ashpit, and to which air is supplied under pressure; and conduits connecting this
box, with the front of the furnace above it, by which some of the air supplied to
said box is delivered into the pile of fuel at the front of the furnace, whereby the
fuel at this part is rapidly coked, and its combustion assisted; substantially as
set forth.
2. A mechanical stoker for furnaces worked under forced draught, having a
closed or air tight hopper for containing the fuel, connected with a part in which
air under pressure exists, whereby air under pressure is maintained in the closed
space in the hopper above the fuel; for the purposes specified.
f:
3. In a stoker for furnaces, the air box u, on the furnace front, having the
shaft extending through said box; a detachable cover u; and filling pieces t
fitting in gaps in the sides of the box above the shaft ; substantially as set forth.
4. In a mechanical stoker for furnaces in which the fuel is fed in at the upper
part of the furnace, a box on and projecting in front of the furnace front enclos
ing the front of the ashpit, and a shaft, for operating the fire bars, passing later-
ally through the sides of said box in air tight bearings, and an air conduit, or air
blowers on said box, by which air is supplied to the ashpit under pressure; sub-
stantially as and for the purposes set forth.
5. In a mechanical stoker or furnace, the air box u, the shaft extending
through it, and the hand door u opposite the ashpit; substantially as set forth.
6. In mechanical stokers for furnaces, the box u and shaft t, filling strips
fitting in gaps in the side of the box, a cover u¹, flanges on t², and bridge bar t
and fastening bolt ; substantially as set forth.
7. In a mechanical stoker for furnaces, the combination of a front furnace plate b,
enclosing the front of the furnace; internal detachable shield plates d, and a feed-
ing device on the upper part of the plate b, through which the fuel is supplied
to the furnace; substantially as set forth.
8. In a mechanical stoker for furnaces, air conduits e, communicating between
the upper part of the box u, and the furnace front; substantially as set forth.
9. In a mechanical coking stoker, the air supply conduits h, communicating
with the sides of the box , and carried up through the plate b above the fuel
feeding device c, and having air openings to the furnace above the fuel; sub-
stantially as set forth.
10. In a mechanical stoker for furnaces, the lid on the top of the air box,
having an upwardly projecting ledge on the lid u, fitting in the open part
of the bottom of o in the plate b; and making part of the seat against which the
door p fits; substantially as set forth.
P
11. In a mechanical stoker for furnaces, the double doors comprising a hollow
box door hinged on ; and a front door p³ hinged on p; substantially as set forth.
12. In a mechanical stoker of the coking type for furnaces, the hollow box door p
hinged on b, and provided internally with a protruding perforated plate p', air
being admitted into the space within said plate, from below; substantially as set
forth.
13. In a mechanical stoker for furnaces, a coking plate i having a valve under
the open lower end of the grid p; and the fire bar door being adapted when closed,
by an incline p or other suitable device, to open the valve 22 to admit air behind pl;
substantially as set forth.
14. In a mechanical stoker of the coking type, for furnaces, having a fuel feed-
ing device of less width than the grate; a coking plate at the front end, extending
further along the grate at the centre, than at the sides, where by an equal distribu-
tion of fuel into the grate, laterally, is effected.
15. In a mechanical stoker for duplex furnaces, the fire-bar actuating shafts t,
having on their outer ends externally cylindrical sleeves, working in bearings s;
a central sleeve 3 pinned onto the adjacent ends of the shafts t, the sleeve being
cylindrical externally, and serving both as a coupling and journal for said shaft;

page_text: and a single central bearing s¹ in which said sleeve $2 revolves; substantially as
set forth.
16. In a mechanical stoker for furnaces, having longitudinally moving grate
bars, the combination of side fixed bars k; internal bars 7 supported by k, and having
projections ; and bars m with slots in them, in which the projecting parts
work, and fitting up against the sides of the furnace; substantially as set forth.
17. The arrangement and construction of parts as set forth with reference to
and shewn in the different figures, or sets of figures of the drawings, for the
purposes specified.
1
5th of Anul 1908
CHEESBROUGH & ROYSTON,
Applicant's Patent Agents, 15, Water Street, Liverpool.