Improvements in or relating to Boiler and other Furnaces.
Year: 1899

page_text: Improvements in or relating to Boiler and other Furnaces.
I, EDWARD BENNIS, of Beech Hill, Astley Bridge, Bolton, in the County
of Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to apparatus for supplying fuel and air to furnaces and
keeping the fire at the highest state of efficiency.
In carrying my invention into effect, I provide a hopper for the fuel and a
box preferably rectangular in shape, the bottom of which is extended so as to form
a shelf or table for the feed plate to rest on. This feed plate is moved to and
fro by a bell crank lever actuated by a scroll cam, which cam has an equal
number of lifts upon it to those on a cam to be hereinafter described, which
operates a plate which pushes the fuel into the furnace. The scroll cam is so
constructed that the distance apart of the portions or sides constituting the cam
groove can be regulated or adjusted by means of a lever and screw, thereby
regulating the throw of bell crank lever and the amount of fuel fed to the
furnace by the feed plate. In my earlier experiments the fuel when small and
dry was apt to run through the box and choke the fire and so produce smoke.
Now this is entirely obviated by means of a plate which is suspended on a pivot
in the box and extends downwards nearly to the level of the front of the feed
plate and at the point that such plate reaches when pushed forward, so that when
the feed plate is drawn back a space or recess is left to be filled with fuel and
when moved forward pushes such fuel under the suspended plate and over the end
of the shelf, each successive push causing nearly the same amount of fuel to be
pushed over, the exact quantity being regulated by the screw. This plate is
preferably held in position by a spring and stop so that it can give way slightly,
but may be operated by weight only.
The effect of this arrangement being to entirely prevent fuel being fed, except
when pushed over by the plate, is simply a necessity for marine firing where
the motion of the vessel would otherwise cause the fuel to run through of itself.
The fuel which is pushed over the shelf falls on the bottom of the box in a
heap across and in front of a striker.
This striker consists of a plate of steel or other suitable material, the front
of which is V-shaped for the purpose of causing the fuel to be scattered all over
the fire, and the top is turned over to form a shield to prevent the fuel getting
behind it when it passes beyond the end of the shelf, this shield never entirely
leaving the shelf.
The striker is fastened to or forms a part of a striker arm arranged on the
outside of the box and is bent round to avoid the shaft and also to give springiness
and which passes down one or both sides of the box and is bent under to clear.
The upper portion of the striker is mounted on a pin or shaft and has a projec-
tion upon it for a cam to bear against, and it is pivoted to a piston rod to he
hereinafter described.

page_text: The striker arm is operated by the spring actuated piston rod which works in
the cylinder and has a piston with piston rings thereon.
A spring presses against the piston in such a manner as to push the striker
through the action of the striker arm toward the fire.
This piston is made so as to form a plunger and fill up the closed space at the
other end of the cylinder. The tension of the spring is regulated by the end
of the cylinder having a thread so that it can be screwed into the cylinder to
any desired extent. If the cam or tappet be rotated the striker arm is pushed
back carrying the striker with it and when released by the cam it bounds
forward among the fuel deposited by the pusher plate, in front of it, and scatters
the fuel over one zone of the fire.
The cam wipers have each a different radius so as to push back the striker
to various distances and so put the spring into various degrees of tension, so as
to throw the fuel to different distances, the closed end of the cylinder being
unaltered and acting as a buffer to take up the unexpended force.
The cam may have either three or four wipers but in either case at each
revolution of the cam all the fire is covered and the action recommences.
The lifts on the scroll cam that actuate the lever are made of varying heights
to correspond with the extent of the throw, the lesser throw having a less feed
as the front of the fire gets a small amount from each throw and were the feed
always equal would get too much and the fire would not be equally good.
The cam and striker cam are both on the same shaft, which passes through
the boxes and is driven from one end by any suitable gear.
The front end of the fire bar is in the form of a circular tube, the narrowest
portion being about 3 inches from the front, widening for about 15 inches away
from the front and also widening to the front so as to form a hell mouth. About
18 inches from the front the bars are of a U cross section cast open at the top,
but closed with small grid bars about three or four in the length of a bar. These
grid bars are sometimes made with teeth, these teeth filling up the space on the
surface of the bar, and forming the platform upon which the fuel rests, and also
forming a zig zag or serpentine air opening extending nearly the whole length
of the furnace part of the har; the back end of the bar being a comparatively
solid casting with a single air space in the centre for the purpose of holding the
grids in place.
In place of the serpentine opening it is obvious that the upper surface of the
bar can be formed of a series of smaller bars held in the sides of the main bar,
or that numerous slits longitudinal, oblique or transverse can be formed in the
upper surface of the bar instead of the single serpentine slit. When such bars
are used they are made with ribs on them placed at a suitable angle to throw the
air into the fire and at the same time to lock the bars together.
The bar is made with openings cast in the bottom, alternately at each side to
let the small ash that drops in from above fall through, but as the air would
escape through these openings. I put a loose plate in the bottom of the bar with
corresponding openings in it. This plate is made in the form of a roof on the top
side so that as ash drops through it falls to one side or the other.
This plate is preferably held stationary and so placed that when the primary
bar is moved in or out, the holes in the plate and the bar come in line and the
ash drops through, and the opening is again closed as the bar reaches the end
of its movement, the bar coming over the openings.
When the bar moves into the fire, in a manner hereinafter described, the holes
in the bar or plate come opposite the holes in the fire bar, and any dust which
may have accumulated drops through, the holes being immediately closed again,
so that very little air escapes.
On the bar is cast a chilled piece, against which a cam works to draw out
the bar. This cam is so arranged that it only brings out one bar at once out of
every 4 or 5, the cams being set one behind the other. The bar next to the
side bar, that is the bar at each end of the furnace, has a piece on it underneath

page_text: the bars, so that when the cam presses against these two bars they are pushed
into the fire 2 to inches carrying all the other bars in with them by means
of a rod preferably a flat piece of steel that presses against a projection on each
bar. The end bars have two such projections so that when the bars are all pushed
in they bring out the rod again. These two bars are so placed and the cams so
arranged that when they have pushed in all the bars, they immediately return,
the cam that brings out these two bars is placed on the side instead of under the
bar and the projection against which it works is on the side of the bar. This
projection is covered by a piece of hard steel which can be renewed. The bar
rests upon a roller, which in turn rests upon a bearer. This bearer is cast with
perforations in it to enable dust to fall through, which would otherwise accumu-
late and interfere with the action of the rollers. This action is most important,
as the fire is carried by the whole of the bars moving in together away from the
front, and when the bars return one by one they do not bring the fire back
with them, but the clinker breaks off and ashes fall through the bars, thus
keeping the furnace at its highest efficiency.
The rollers are placed under the bar preferably towards the front, and flanges
are cast on the bar extending about half way down the roller to prevent it moving
away from its proper place: these flanges being extended to where the cams
work that drive the bars in and out, so that these also are kept in their place and
cannot move from their position, which would otherwise cause a breakdown.
A dead plate projects over the front grid and keeps the same in position, and
the front grid locks the second, and the second the third, so that they cannot be
disturbed by the attendant in raking the fire when such is necessary.
The grids which close the bars at the top are made with the teeth pointing
towards the front of the bar at the bottom, and of a V section, so that the air
rushes up between them with great force into the fire, and is caught in its passage
down the bar, so that the front of the fire is as good as the back, and thus equal
combustion secured over every part of the furnace.
At the front of the bars a steam tube is arranged having nipples which point
nearly to the centre of the bar. The steam is superheated, preferably by passing
it into one of the flues through a steam tube which is suitably placed to take up
the heat from the boiler Hue. The steam rushes from the nipples at a short
distance from the bar and the air is driven into the bar with great force,
resulting in a larger combustion of fuel and more economical results, as well as
the prevention of smoke.
The small bars or grids that make up the main fire bar are sometimes simply
straight sections with side ribs on them at an angle to guide the air and cause
it to ascend into the fire, and the same arrangement of locking would be applicable
in this case, but I distinctly prefer the zig zar bars, as they are more efficient and
better in every respect.
The cams are locked on to the shaft preferably by a hollow space or groove cast
or cut into the shaft, and a piece cast on the cam that fits into this hollow.
11.... £ 1900
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
Improvements in or relating to Boiler and other Furnaces.
I, EDWARD BENNIS, of Beech Hill, Astley Bridge, Bolton, in the County
0 of Lancaster, Engineer, do hereby declare the nature of this invention and in

page_text: what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention relates to improved apparatus for supplying fuel and air to
furnaces in due proportion one to the other, and removing the clinker and ash
continuously from the fire.
The invention will be understood from the following description, reference
being had to the accompanying drawings, in which,
Fig. 1 is a side elevation of stoker fitted to internally flued boiler;
Fig. 2a plan view of box (A) with feed motion striker (J), and tappet
motion (K);
Fig. 3a part sectional side elevation of box (B) with tappet (K), striker (J),
striker arm motion and hanging plate (H), representing position of striker (J),
after a charge of fuel has been thrown on to the furnace.
Fig. 4 a longitudinal section through a Fig. 2 but on a larger scale, the
striker arm being in the position it occupies just before a throw occurs and
the dash pot mechanism actuating striker being shown in dotted lines as it is
cut away by this section, the cylinder of such mechanism being shown half
in section and half in elevation.
Fig. 5 shows two detail views of scroll cam (E) and ends of levers (1) & F).
Fig. 6 and Fig. 6a show a side elevation of outside moving furnace troughs N³,
bars (0) and sectional elevation of driving cams (Q, Q¹), driving mechanism with
bearer (U) roller (T) and steam tube (X).
Fig. 7and Fig. 7a show a side elevation partly in section of moving furnace
troughs (N), fire bars (0) ash plate (P), dead plate (W), rod (S) and driving
mechanism of moving furnace troughs.
Fig. 8 a cross section of moving troughs with ash plate (P) made roof shaped,
Fig. 9 a cross section of moving furnace trough near bell-mouth with roller (T),
Fig. 10, cross section of moving furnace troughs as they appear in a furnace,
Fig. 11 and Fig. 11ª show a plan of moving furnace troughs with ash plate (P),
apertures (P), fire bars (0), steam tube (X), nipples (X1), side bars (Z), cams (Q¹),
and rod (S).
In carrying my invention into effect, I provide a hopper (A) for the fuel, and
a box (B) preferably rectangular in shape, the bottom of which is extended so
as to form a shelf or table (13) for the feed plate (C) to rest on. (See Figs. 1,
2, 3, 4). This feed plate is moved to and fro by a bell crank lever (D) actuated
by a scroll cam (E), which cam has on it an equal number of waves or projec-
tions (E, E, E3, 14) to those on a tappet to be hereinafter described, which
tappet operates a plate or striker, which throws the fuel into the furnace.
The scroll cam (E) is so constructed that the distance apart of the portions or
sides constituting the cam groove can be regulated or adjusted by means of a
lever (F) and screw (G), thereby regulating the throw of bell crank lever (D)
and the amount of fuel fed to the furnace by the feed plate (C), (see Figs. 2
and 5):
In my earlier experiments, the fuel when small and dry was apt to run over the
end of the shelf (B) and choke the fire and so produce smoke. Now this is
prevented by means of a plate (H) which is suspended on a pivot (H) in the
box (B) and extends downwards nearly to the level of the front of the feed
plate (C) at the point that such feed plate (C) reaches when pushed forward, so
that when the feed plate (C) is drawn back, a space or recess is left to be filled
with fuel and when moved forward pushes such fuel under the suspended plate (H)
and over the end of the shelf (B1), each successive push causing nearly the same
amount of fuel to be pushed over, the exact quantity being regulated by the
opening or closing of the scroll cam (E) operated through the lever (F) by means
of screw (G) and hand wheel (GI). The plate (H) is preferably held in position
by a spring (H2) and stop (132) so that it can give way slightly, and may be
operated by weight in place of spring (H2).
The effect of this arrangement is to entirely prevent fuel being fed, except when

page_text: pushed over by the feed plate (C). The fuel which is pushed over the shelf (B')
falls on the bottom of the box (B) in a heap across and in front of a striker ().
This striker (J) consists of a plate of steel or other suitable material, the front
of which is V shaped (see Fig. 2) for the purpose of causing the fuel to be
scattered all over the fire, and the top is turned over to form a shield to prevent
the fuel getting behind it when it passes beyond the end of the shelf (B). This
shield never entirely leaving the shelf (B) see Fig. 3.
The striker (J) is fastened to or forms a part of a striker arm (J¹) arranged on
the outside of the box (1) being bent round both to avoid the shaft (Y) and to give
it elasticity. The striker arm (J) passes down one or both sides of the box (B)
and is bent under to clear, see Figures 3 and 4. The upper portion of the striker
arm (J) is mounted on a pin or shaft (J3) and has a projection (J2) upon it for
a tappet (K) to bear against, and it is pivoted to a piston rod (L) to be herein-
after described.
The striker arm (J¹) is operated by the spring actuated piston rod (L) which
works in the cylinder (L) and has a piston (L) with piston rings thereon, to
act as a dash pot or buffer. A spring (1) presses against the piston (Le) in such
a manner as to push the striker (J) through the action of the striker arm (J)
toward the fire. The air in the cylinder (L) not only acts as a dash pot or
buffer but it brings back the striker (3) to the point of rest. The tension of the
spring (L) is regulated by the end of the cylinder (L) which has a thread so
that it can be screwed into or out of the cylinder to any desired extent.
If the tappet (K) be rotated, the striker arm (J) is pushed back carrying the
striker (J) with it, and when released by the tappet (K) it bounds forward among
the fuel deposited by the feed plate (C) in front of it, and scatters the fuel over
one zone of the fire. The tappet projections (K', K², K³, K+,) have each a
different radius So as to push back the striker (J) to
various
distances and to put the spring (L) into various degrees of tension,
thereby throwing the fuel to different distances, the closed end of the cylinder (L)
being unaltered and acting as a buffer to take up the unexpended force, as already
explained. The tappet (h) has preferably three or four projections or teeth, but
in any case at each revolution of the tappet (K) all the fire is covered and the
action recommences.
The waves on the scroll cam (E) that actuate the lever (D) are made of varying
heights to correspond with the extent of the throw. When there is a long
throw there is a large feed, and conversely with a short throw there is a less
feed. This is done because the front of the fire gets a small amount from each
throw and were the quantity fed to the striker always equal the front of the fire
would get too much fuel, and the fire would not be even.
The scroll cam (E) and tappet (K) are both on the same shaft (Y) which passes
through the box (B) and is driven from one end by any suitable gear such as (M).
Referring now to Figures 6 to 11 inclusive, the portion of the moving furnace-
trough (N) outside the furnace is in the form of a tube, bell-mouthed at the front.
This bell-mouth continues for about 3 inches, the tube then expands at an angle.
of about 5 degrees in the diameter to the part where the furnace begins. The
remainder of the moving furnace-troughs (N) are of a channel or U cross section,
open at the top, with small cross bridges (N) cast thereon at intervals supporting
a number of small fire bars (0) or grids. These firebars (0) have on themi fin-like
ribs (0) inclined at a suitable angle to guide the air into the fire in the direction
in which the gases are to travel. The moving furnace-troughs (N) are made with
openings (2) cast in the bottom alternately at each side to allow the small ash
that drops through the small fire bars (0) to fall through, but as the air would
escape through these openings, a loose ash plate (P) is arranged in the bottom
of the trough (N) with corresponding openings (P) in it. This ash plate (P)
is made in the form of a roof on the top side so that as ash drops on to it, it falls
to one side or the other. This plate (P) is preferably held stationary and so
placed that when the moving furnace-trough (N) is moved in or out, the holes

page_text: (P) in the plate (P) and the holes (N) in the moving furnace-trough (N) come
over one another and the ash drops through and the openings are again closed
as the moving furnace-trough (N) reaches the end of its movement, the ash
plate (P) coming over the openings. When the moving furnace-trough (N) moves
into the fire, in a manner hereinafter described, the holes (P) in the ash plate (P)
comes opposite the holes (N2) in the moving furnace-trough (N), and any dust
which may have accumulated drops through, the holes being immediately closed
again, so that very little air escapes.
'
The moving furnace-troughs (N) are operated as follows, to give the outward
movement:
On the moving furnace-troughs (N) are cast chilled pieces (N³, №4) against
which cams (Q, QQ) work to draw out the moving furnace-troughs (N). These
pieces are on the bottom of the inner moving furnace-troughs and at the side of
the outside furnace troughs, and may be capable of being renewed. The
cams (QQ³) are so arranged that they only bring out one moving furnace-
trough (N) at once out of every four or five, the projections (Q, 3, 4) of the cams
being arranged at different leads. To give the inward movement, the two outside
troughs (N) next to the side bars (2), that is, the one at each side of the furnace,
has a chilled piece (N) on it underneath it. This projects underneath the
cams (Q), so that when the cams (Q) press against it these two outside furnace-
troughs, (N), are together with the inner furnace-troughs pushed into the fire
two or three inches. On the top of each of these two outside moving furnace-
troughs (N) are cast two projections (N° and N7) between which rests a rod or
bar (S) preferably of flat steel. This rod (S) thus moves in and out at the same
time as the outside moving furnace-troughs (N). On the top of each of the inner
moving furnace-troughs (N) there is cast one projection (N8) against which the
rod (S) presses, so as to move the whole of the inner moving furnace-troughs
inwards simultaneously with the outer moving furnace-troughs. After the whole.
of the moving furnace-troughs are moved inwards, the two outside moving furnace-
troughs are immediately pushed outwards, again bringing the rod (S) with them.
The moving furnace-troughs (N) rest upon rollers (T) which in turn rest upon
a bearer (U). This bearer (U) is cast with perforations in it to enable dust to
fall through, which would otherwise accumulate and interfere with the action
of the rollers (T). The rollers (T) are placed under the moving furnace-
troughs (N) preferably towards the front, and flanges may be cast on the moving
furnace troughs extending about half way down the roller to prevent it moving
away from its proper place these flanges may be extended to where the cams
work that drive the moving furnace-troughs in and out, so that these also are
kept in their place and cannot move from their position.
The cams Q, Q¹ etc.) are locked on to the shaft (V) preferably by a hollow
space or groove cast or cut into the shaft (V) and pieces cast on the cams to form
keys that fit into this hollow.
A dead plate (W) (Figure 7) projects over the front bars (0) and keeps the
same in position, and the front bars lock the second, the second the third, so that
they cannot be disturbed by the attendant in raking the fire when such is necessary
the end of the moving furnace-troughs being closed by the blocks (N10), (as shown
in Figures and 11").
At the front of the moving furnace-troughs (N) a steam tube (X) is arranged
having nipples (X) which point into the bell mouths. The steam is super-heated,
preferably by passing it into one of the flues through a steam tube which is
suitably placed to take the heat from the boiler flue.
The steam rushes from the nipples (X) into the moving furnace-troughs, and
the air is drawn into the moving furnace-troughs with great force, resulting in
a larger combustion of fuel and more economical results, as well as the preven-
tion of smoke.
The fin-like ribs (O¹) on the fire bars (0) are disposed at suitable angles and in

page_text: such a manner that they turn about the same quantity of air up at the front of
the fire as at the back, so that the supply of air is practically uniform all over.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. The improvement in furnaces which consists in the combination of a series
of hollow bars made at front end in the form of a tube, trumpet mouthed, for
receiving jets of steam, but for the remainder of their length in the form of
troughs open at the top with cross grids at intervals, and fire bars supported
at their ends in these troughs on the said grids substantially as described.
2. In furnaces having sliding grate bars, the combination with the trough
shaped furnace bars of a loose ash bar made roof shaped on its top, and arranged
in the bottom of the trough, said har having holes adapted by means of a sliding
movement to momentarily register at intervals, with holes in the trough, whereby
while the dust can freely fall through, the escape of air is in large part prevented
substantially as described.
3. In furnaces, the combination of moving grate bars having abutments near
the front end, a cross bar or shaft adapted to interlock with the bars when
pushed into the fire, and cams-one set of which are arranged with different
leads to strike against the abutments on some of the bars, and the other set
arranged in line (or with equal leads) to strike against the abutments on the
remaining bars-whereby one set of cams will by means of the cross shaft send
them all into the fire together, while the other set draws the bars out separately,
substantially as described.
4. The combination of devices for alternately bringing the bars forward one by
one separately, and returning them all together. substantially as described.
5. In furnaces formed with trough shaped bars open at the top and having
fire bars or grids supported therein, forming the said bars or grids with thin
light ribs at their sides inclined at a suitable angle and so arranged as to guide
the air into the fire in the direction in which the gases are to travel sub-
stantially as described.
6. In furnaces with moving grate bars, the arrangement for feeding fuel into
the fire in determined quantities, constructed, arranged, and operating sub-
stantially as hereinbefore described with reference to and shown in Figures 1 to 5
inclusive of the drawings.
7. In furnaces, the arrangement for regulating the amount of fuel fed to the
furnace, which consists in arranging the scroll cam which operates the sliding
feed plate so that the distance anart of the portions or sides constituting the
cam groove can be regulated or adjusted substantially as described with reference
to and shown in Figure 2 of the accompanying drawings, substantially as set
forth.
8. The adjustable spring controlled hanging plate H in combination with
nusher C and hopper A. substantially as described with reference to and shown
in the drawings annexed.
WM. P. THOMPSON & Co.,
Patent Agents, of Liverpool, Manchester, Birmingham & London.