Improvements in or relating to Steam Boiler or other Apparatus for Supplying Fuel thereto.
Year: 1888

page_text: Date of Application, 21st June, 1888
Complete Specification Left, 20th Apr., 1889
Complete Specification Accepted, 8th June, 1889
Improvements in or relating to Steam Boiler or other
Apparatus for Supplying Fuel thereto.
rnaces and
تیرا
I, ALFRED WILLIAM BENNIS, of Blackburn Road, Bolton, in the County of Lan-
caster, Engineer, do hereby declare the nature of this invention to be as follows
This invention relates to improvements in boiler & other furnaces and to supplying
fuel to the same and in apparatus therefor.
I construct a hopper which I place over what I call the feed box-in which hopper
the fuel is placed.
Below this hopper is the feed box in which a pusher plate is moved to & fro-to
push regulated quantities of fuel to the front of a shovel-placed below the feeding
apparatus where space is not the more important consideration-but where space is
very important the fuel is pushed by the pusher from one side on or about the same
level as the bottom of the shovel.
This pusher is moved by a cam acting directly on it, or by a lever which is actuated
by a cam and the quantity of fuel fed at each stroke of the shovel is regulated by the
distance the plate is made to move by the longer or shorter cam which moves it-as
I find it very important that when the shovel distributes the fuel on the front part of
the fire the weight of fuel supplied should not be the same as when the shovel
sends its charge to the back part of the furnace, further away from the fire door.
The total weight of fuel supplied is regulated by a screw or a nut which increases or
decreases the feed of all the movements of the feed plate.
As an alternative plan for feeding the fuel in front of the shovel I sometimes use a
chambered revolving feeder, which measures the fuel & throws it down in front of
the shovel, between guides to prevent it spreading away from the shovel-but for
most purposes I prefer the pusher.
The throwing apparatus consists by preference of a steel thrower or striker, with
the front part which strikes the fuel of a V shape so as to throw the fuel more to
the sides & less to the middle of the furnace.

page_text: This shovel, thrower, or striker, is attached to a rod or lever-or may be forged or
cast in one piece with it-& is arranged to work to & fro in the shovel box which is
cast on or attached to the feed box-& open to the boiler with a wide mouth to allow
the fuel to spread.
In this box the shovel moves-backward with a slow motion & forward with a
quick motion, the former through the action of a cam having different lifts--the latter
throught the rebound of a spring acting directly on the shovel, or through the
medium of a lever, rod, shovel arm, or other suitable attachment.
For different purposes I vary this attachment as :-
I attach a spring to each side of the shovel lever-so that when the lever is drawn
out by the action of the cam these two springs are simultaneously placed in tension
or compression as may be arranged-and when the cam releases the shovel & it
rebounds the springs after passing the point of rest are again placed in tension
or compression thus taking up the unexpended power and forming a noiseless &
perfect buffer.
By this arrangement among other advantages one spring balances the other &
friction is avoided or lessened & reduced to a minimum-and much less powerful
springs may be employed for equal work.
This plan can be adapted to throwers actuated by a shaft-whether of the door
flap or shovel type-as in case it was convenient to use such an apparatus I would
attach a spring to a pin on one side of a shaft & drawn out directly away from it &
a second spring at the opposite side so that when the spring was placed in tension
there would be no pressure on the bearings.
In one of my arrangements I use a slightly weaker spring at one side than the
other for the purpose of balancing the motion of the secondary lever which serves as
a guide for the lever or rod to which the shovel is attached.
The shovel lever may be attached to a swing lever on the side or back of the feed
box or shovel box or may act in slides and the cam may act on it directly but the
mode of attachment which I prefer is:-
I hang a lever working on a pin on a projection from the box.
This lever moves nearly in a horizontal plane-one end passing nearly to the centre
of the shovel box to which end the shovel lever is attached by means of a pin or
other suitable attachment.
The cam with variable lifts presses against this lever or against a suitable projection
on this lever so as to draw out the shovel against the action of the springs, until
the cam releases the lever and the shovel bounds forward with varying force, projecting
the fuel onto the fire to such distance as may be desired.
Another form which 1 sometimes use is that of a lever attached to the side of the
box & turned underneath it for the purpose of attachment as in the patent No. 4245
of 1887.
Another very convenient form is a lever attached to a short shaft passing through
the feed box & which hangs down about the middle of the box & is attached in a
suitable manner to the shovel lever.
This shaft may be moved by the same cam that actuates the feeding apparatus
or by projections thereon or by a cam placed on the driving shaft as may be
convenient.
When the horizontal lever is used which is for most purposes the most valuable
combination I sometimes use only one spring attached by one end to this lever
where the shovel lever joins it & by the other end to a projection on the opposite
side of the box-which spring is drawn into tension when the lever is pressed out &
again drawn into tension when the lever has passed its rest-thus acting both for
driving & buffering.
Another arrangement which in many cases possesses great value is to have two
springs, generally of unequal power attached at an angle to each other either
to the lever just mentioned or two pins placed in a shaft or other suitable manner.
The angle at which these springs are attached must be proportioned to the intended
movement.

page_text: When the lever or shaft is pushed out one spring is placed in tension & exerts
its power to great advantage-while the other spring in consequence of the angle at
which it is placed is merely in reserve & neither compressed nor extended to any
great extent.
When the lever or shaft is released the driving spring becomes inoperative after
the point of rest has been reached & the second spring comes into action for the
purpose of buffering-but without any jar or noise.
Usually both springs are kept when at rest at a slight tension.
When space becomes the most valuable consideration I use a horizontal cam under
the feed box with projections on one side to drive the feeding apparatus, and on the
other side to drive the throwing apparatus.
I make by preference the bottom of the shovel box slant down towards the boiler
as far as the shovel acts & from that point either straight or a slight rise for the
purpose of preventing any fuel going over without being struck.
For marine work I use shovels having the centres more or less placed at one side
& which are easily and quickly changed one for the other-so that if a vessel lies
on one side the shovel may be altered to throw the bulk of the fuel to the higher
side & vice versa.
I also meet this difficulty by rounding the bottom of the shovel box & making the
shovel as before with its centre more or less to one side-by which means I enable the
engineer to keep his fire level under adverse conditions.
I also provide a central guide in the feed box so that more fuel may be guided to
the higher side.
Another very useful arrangement for marine work is to have a smaller thrower at
each side of the fire door & the hopper above the fire door-the fuel being pushed
alternatly to each side & thus each side of the fire would receive its own share, the
hopper being thus brought low down & being fitted under the smoke box.
The effect of these arrangements are that as each lift of the cam comes into opera-
tion the fuel thrown to a varying distance & distributed across the fire thus covering
only a portion at once and allowing the fuel to become incandescent before another
charge is thrown in the same place.
There is no mode of firing known, so effectual as this for the prevention of
smoke.
For the still further prevention of smoke I arrange the furnace door and the
protection plates on the inside of the front so as to utilize the heat they acquire from
the furnace to heat a current of air passed through them which air is thrown down
on the fire in its heated condition, producing intense combustion at the front-and
thus still further tending to prevent the production of smoke.
The door is constructed with an open space at the bottom of the outside into which
a current of air passes.
This air passes through a perforated plate & then plays against a sheet iron plate
which guides it to the top of the door where it passes over this plate & then down
to the bottom of the door, where it blows on the front of the fire.
The protection plates on the front are constructed in a similar manner only modified
to meet the circumstances.
The opening into the door is closed at night by a small cover.
The furnace bars I prefer are what may be called swan-neck bars.
These bars are constructed with a head outside for the purpose of movement &
just inside the fire door there is a deep depression of say 3 to 5 inches-there is then
an incline upwards for about 12 inches to keep the fire from travelling too fast from
the front.
After this point the bar falls about 1 inch to the foot until within 6 inches of the
end when it again rises a little to prevent the clinker leaving the bars too soon as shown
in specification No. 424587.
The head of the bar is made with a jaw with a projection cast on one side of the
top & another projection on the bottom.
A cam shaft is placed across-against which the cam on the shaft presses & pushes

page_text: all the bars in from 1 to 2 inches or as may be arranged-while as the shaft turns
round washer cams placed at different points draw out the bars one by one-thus
effectually breaking up the fire & moving forward the clinker till it drops over the
end of the bars into a closed chamber.
I sometimes use another form of bar in which the bars rest on a lever one half
rising & falling & the other half moving to & fro-but this is not nearly so effective-
though much cheaper to construct.""
For marine purposes I generally use a furnace in which one half of the bars are
stationary while the other half rise up, go forward, fall below, & return.
The stationary bars are made to bear against each other so that if a vessel is lying
on one side they keep the moving bars in place.
The stationary bars are made hollow & air driven through them either by a fan or
by means of small steam jets.
I also sometimes make my ordinary bars hollow & drive air through in a similar
manner to keep the bars cool & to increase combustion & prevent smoke.
For this purpose I prefer to carry the air from the front to the end returning to
the front & there entering the fire.
But I sometimes admit the air at the back end of the bar or when desirable cause
it to enter at the front & leave the bar at the end, protecting it from the action of
ash & clinker.
For marine & other purposes it sometimes is important to prevent any tendency
to fuel falling before the shovel-except when pushed by the pusher-when this is
necessary I use a plate to swing against the fuel & open at the right time or a slide
to close the opening when no fuel should fall.
Sometimes instead of a sliding shovel I use for marine purposes 2 doors-one
at each side hung like a house door-with a division line in the centre-so that
the fuel thrown by the Right hand door will all go to the right hand and that on
the left to the left side-and these doors can be operated in one of the above mentioned
ways.
I sometimes place a piece of sheet steel projecting from the shovel toward
the fire to still further secure this even distribution when I use the sliding shovel.
Dated this 20th day of June 1888
WM. P. THOMPSON & Co.,
6, Bank Street, Manchester,
Patent Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to Steam-boiler or other Furnaces and
Apparatus for Supplying Fuel thereto.
I. ALFRED WILLIAM BENNIS, of Blackburn Road, Bolton, in the County of
Lancaster, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
This invention relates chiefly to apparatus for supplying fuel to steam boiler and
other similar furnaces known as mechanical stokers, and is designed with the object
of making such apparatus more efficient and simple in construction.
It consists essentially, in constructing and arranging the apparatus with the arm
of the shovel working horizontally on a vertical pin or pivot, or the shovel in the
form of a door working from a vertical shaft; in providing two or more shovels of
different shapes that may be readily interchanged at any time that the direction of the
coal being delivered requires to be altered; in actuating the throw of the shovel and
buffering it by means of two or more springs set at an angle to each other so that
on the movement of the shovel or shovel arm in one direction one spring will be
brought into operation and in the opposite direction the other spring, or by means of
two or more springs placed on the same axial line acting in opposite directions to prevent
undue pressure on the bearings of the shaft or arm which both come into operation
at the same time; and in the arrangement of a mechanical stoker for a marine boiler
with two feed boxes and shovels for each flue, one placed at each side of the fire door
and the hopper placed above the door so that the apparatus will not interfere with the
present construction and arrangement of smoke box and fire door..
The invention will be fully described with reference to the accompanying drawings
which show sufficient of a mechanical stoker to illustrate my invention.
Fig. 1, is a front elevation of feed box and shovel box showing that part of my
invention relating to the horizontal shovel arm and application of springs set at an
angle to each other.
Fig. 2, plan view of shovel box showing same.
Fig. 3, plan of shovels for throwing fuel to either side of furnace.
Fig. 4, elevation of feed box and shovel box showing the application of that part
of my invention relating to the springs set on the same axial line.
Fig. 5, plan of same."
Fig. 6, elevation of feed box and shovel box showing the shovels in the form of
doors connected to a vertical shaft or pivot.
Fig. 7, plan of same.
Fig. 8, elevation showing my invention of applying two feed apparatus to the flue of
a marine boiler one on either side of the door.
A hopper of ordinary construction to receive the fuel is placed over the feed box a.
holted or otherwise attached to it in the usual manner. a is the feed box into which
the fuel passes from the hopper and from which it is delivered in regulated quantities

page_text: to the shovel box b, in front of the shovel-thrower c, in any convenient manner such as
is at present adopted, by a pusher plate moving to and fro in a feed box above the shovel
box, or where the economy of space is of importance by a pusher acting first on one
side and then on the other in a feed box on about the same level as the shovel box,
but I prefer the feed box above the shovel box. The pusher is moved by a cam or
tappet or in any well known way and the weight of fuel supplied at each throw is
regulated by a screw acting against a swinging feed plate.
Other forms of feeding apparatus I may use such as a chambered revolving feeder
which measures the fuel before delivering it to the shovel box, but I prefer to use the
reciprocating pusher as the amount of fuel can be more easily regulated and it can
be more readily adjusted to varying descriptions of fuel.
The throwing apparatus I prefer to use is that formed of a steel shovel-thrower or
striker, V shaped to the front side (as shown in fig. 2) so as to throw the fuel more
to the sides than to the centre of the furnace.
The shovel-thrower c is arranged to work to and fro in the shovel box b, it is attached
to a rod, arm, or lever d by means of a stud e on which it moves freely. The lever d
is pivoted on a vertical stud or pin f secured to the shovel box and moves in an
approximately horizontal plane, the end that carries the shovel passing nearly to
the centre of the shovel box. The lever d is preferably pivoted on the under side of
the shovel box and the pin or stud e passes up through a slot e¹ on the bottom of the
shovel box.
The shovel c is moved backwards with a slow motion and forward with a quick
motion, the former through the action of a differential cam having different lifts, the
latter through the rebound of a spring acting directly on the shovel or through the
medium of the rod, lever shovel arm, or other suitable attachment. The cam g which
draws back the shovel c presses against a projection d' on the arm d, drawing back the
shovel against the action of the springs, until the can releases the lover, and the
shovel bounds forward with varying force projecting the fuel into the fire to such a
distance as may be required.
The function of the spring or springs which actuate the shovel is two-fold, to propel
the shovel forward to project the fuel into the furnace and at the end of its stroke to
buffer it with as little noise or jar as is possible. Several arrangements of springs have
hitherto been devised and used for this purpose but all of them I consider more or
less imperfect in action and I have designed an arrangement of two springs working
in conjuction which will I consider give the maximum result with the minimum
amount of friction to the working parts of the apparatus.
The springs may be arranged to work according to my invention in a variety of
ways, either in tension or compression.
The
Referring to figs. 1 and 2, one arrangement is shown in which the two springs h
and i are set at a suitable angle to each other and to the arm or lever on which the
shovel works. The springs h and i are attached to the shovel arm or lever d as shown
or to two pins placed one on each side of the lever or in other suitable manner.
angle at which these springs are attached is such, that when the arm or lever dis
pushed out the spring h which acts as driver is placed in tension and exerts its power
to great advantage, while the other spring in consequence of the angle at which it is
placed is merely in reserve and neither compressed or extended to any great extent.
When however the lever d is released by the cam and bounds forward, the driving
spring becomes inoperative after the point of rest has been reached and the second
spring comes into action for the purpose of buffering, without jar or noise. Usually
both springs are kept when at rest slightly in tension.
With the horizontal shovel arm or lever d I may in some instances use only one
spring one end connected to it at the point where it is attached to the shovel, the
other end connected to a suitable projection on the other side of the box, which
spring is drawn into tension when the lever is pressed out and again drawn into
tension when the lever has passed its rest, thus acting both for driving and buffering,
as described in patent No. 3070 of 1878 granted to my father Edward Bennis, but
which was difficult of attachment with the class of shovel arm or lever invented and

page_text: patented by him and could not be so easily regulated. By my plan it is com-
paratively easy of adjustment although I much prefer the arrangement above described
in consequence of the more direct action of the springs and much greater power of
regulating the force employed.
Referring to figs. 4 and 5 another arrangement of the two springs h and i is shown
placed on the same axial line and attached to the arm of a shovel which moves to
and fro in a longitudinal direction operated by a cam g as in my previous patent
No. 1436 of 1887. The spring his attached to the arin or lever d at one side and the
spring i at the other side in such a manner that when the said lever is drawn out by
the pressure of the cam against it, these two springs are simultaneously placed in
tension, and when the cam releases the shovel arm and it rebounds the springs after
the shovel arm has passed the point of rest are again in tension, thus taking up the
unexpended power and forming a noiseless and perfect buffer. By this arrangement
among other advantages one spring balances the other, and friction is avoided or
reduced to a minumum and much less powerful springs can be employed for equal
work.
Either arrangement of springs shown in Fig. 2 or 5, particularly the latter, may
be applied to actuate the throwers of other forms of mechanical stoker, either of the
type with a door or flap projecting radially from a shaft or of the striker or shovel
type such as shown in the specification of Church's patent No. 5857 of 1829. In the
case of a machine of the door or flap type I would attach one spring to a pin or lever
projecting from one side of a shaft and draw it out directly away therefrom and a
second spring to a pin or lever at the opposite side, so that when the springs were
placed in tension there would be no spring pressure on the bearings.
In other types of stoker the springs may be arranged in any convenient way so that
when the shovel is stationery both springs are at rest or practically so and when it
is moved by the cam both springs are at the same time brought into operation.
In another arrangement I use a slightly weaker spring at one side than the other
for the purpose of balancing the motion of the secondary lever, which serves as a guide
for the lever or rod to which the shovel is attached. A greater number of springs
may be used placed in pairs so arranged that one pair balances the other.
Referring to figs. 3 and 8 which show parts of the invention specially designed
for marine work 1 provide two or more shovels having their centres placed more or less
at one side or the other which can be easily and quickly removed and replaced.
If a vessel lies on one side the shovel may be altered to throw the bulk of the fuel
to the higher side and visa versa.
In addition to providing shovels of different shape the bottom of the shovel box
may be rounded or a central guide may be placed in the feed box to direct more fuel
to the higher side.
Another very useful arrangement for marine work as shown in fig. 8 is to have a
smaller thrower at each side of the fire door and the hopper above the fire door, the
fuel being pushed alternately to each side, thus each side of the fire would receive
its own share. The hopper is thus brought low down and fitted under the smoke
box.
Referring to figs. 6 and 7 in which are shown an arrangement of apparatus very
suitable for marine work, and are two doors hung on vertical shafts or pivots
one placed at each side of the shovel box. These doors meet in the centre in the
manner of a pair of ordinary swinging doors and in operation one will throw the
fuel to the right hand side of the furnace and the other to the left hand side. Between
the doors may be placed a deflecting plate m to prevent pieces of coal coming
between them and to direct the throw of it onto the furnace. The doors k and Z
may be operated by means of a lever such as d attached to their vertical spindles
moved in one direction by a cam and in the other by a spring or springs in the
manner already described.
With my improved mechanical stoker I may use one of the forms of fire bar at
present in use either stationary or movable and I make no claim herein for the use
of any special form of fire bar.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. A mechanical stoker or apparatus for supplying fuel to steam or other furnaces
having the arm or link which actuates the shovel placed in a horizontal plane
preferably below the shovel box substantially as described.
2. In a mechanical stoker, the combination of two or more springs to actuate and
buffer, each spring so placed at an angle to the other and to the lever or arm to
which it is attached that when the arm or lever is moved in one direction one spring
will be brought into action and when in the other direction the other spring will be
brought into action substantially as described.
"
3. In a mechanical stoker the combination with the shovel door or flap which dis-
tributes the coal or with the arm, link, shaft, or lever thereof, of two springs so placed
on the same axial line that they will act together for propelling and buffering purposes
and at the same time balance the pressure exerted in a lateral direction and so relieve
the friction on the bearing substantially as described.
4. The use or combination with a mechanical stoker of two or more interchangeable
shovels which will deliver the fuel to different parts of the furnace, substantially as
and for the purposes described.
5. The combination with the furnace of a marine boiler of a mechanical stoker
having two feed boxes and throwers one placed at either side of the fire door and
the hopper placed above the fire door substantially as described and shown.
6. A mechanical stoker having the fuel distributing or feed mechanism constructed
of two doors or flaps each extending radially from a vertical shaft or stud and meeting
in the centre of the shovel box substantially as described and shown.
TL: 10th dow of An: 1000
WM. P. THOMPSON & Co.,
Manchester, Liverpool and London,
Patent Agents.