IMPROVEMENTS IN FURNACES FOR STEAM BOILERS AND OTHER STRUCTURES, AND IN APPARATUS FOR FEEDING THEM WITH FUEL
Year: 1879

page_text: LETTERS PATENT to Edward Bennis, of Bolton, in the County of Lancaster,
for the Invention of "IMPROVEMENTS IN FURNACES FOR STEAM BOILERS AND
OTHER STRUCTURES, AND IN APPARATUS FOR FEEDING THEM WITH FUEL."
Sealed the 24th February 1880, and dated the 27th August 1879.
PROVISIONAL SPECIFICATION left by the said Edward Bennis at the Office
of the Commissioners of Patents on the 27th August 1879.
EDWARD BENNIS, of Bolton, in the County of Lancaster. "IMPROVEMENTS IN
FURNACES FOR STEAM BOILERS AND OTHER STRUCTURES, AND IN APPARATUS FOR
FEEDING THEM WITH FUEL."
This Invention relates chiefly to improvements on Letters Patent granted to me,
No. 1308, of 1875, and 3070, of 1878.
It consists in constructing a machine with the ordinary hopper opening into a
crusher chamber or crusher box, or into a feeding box, on which are ribs cast on
the box or on a cruslier plate to guide the fuel, prevent its return, and break up
any lumps.
On the shaft running through this chamber is placed the crusher, consisting
generally of cast iron or cast steel stars or chambered discs having as many chambers
as there are throws of the shovel to each revolution of the shaft, thus supplying the
fuel to the shovel at any desired point of its movement.
In the crusher box are placed two regulators to control the supply of fuel to the.
shovel box, one of which can completely or nearly completely close the opening into
the shovel box, and the other a plate which controls the supply before it enters the
crusher, by which combination the irregularity (which has been a great objection to
the class of machine which throws the coal into the fire) is got rid of.
On the last named regulator are teeth or projections which when the crusher is,
closed pass between the arms of the star crushers and clear the coal away in a
simple and effective manner, thus preventing the crusher from becoming choked
when fuel is damp.
The opening into the crusher box is so arranged that when the bottom regulator
is closed the fuel simply fills the chamber in the crushers and revolves with them,
and the apparatus does not choke itself, as would be the case with those in common
use if the orifice leading from the crusher or feeder were closed.

page_text: Under the crusher or feeding box is placed a box for the shovel to work in, the
contour of the top and bottom of which forms part of the circumference of a circle
having the same centre as the arm on which the shovel moves. This shovel box has
parallel sides to within a short distance of the boiler front or the front of the shovel
box, where they gradually diverge, the distance being varied according to the breadth
of the furnace.
The throwing or distributing apparatus moves in the arc of a circle, and consists
of a lever hung upon a stud or shaft which forms a centre, and which stud or shaft
is supported preferably by a casting on the side of the crusher box; and attached
to the lever there is a plate which nearly fills up the interior section of the shovel
box, having sufficient room to swing freely therein.
This lever is usually hung just above the crusher shaft, or a little to the front or
back of it, as needed for various furnaces, and the lever is bent in such a manner
as to clear the crusher shaft and any other projection, and to enable the cams to
operate upon it, and. to enable it to enter the shovel box at the side, top, or back, as
may be convenient.
To the end of this lever the shovel is attached in any suitable manner, or may be
formed in one piece with the lever.
On a suitable part of the lever is placed a projection or stud for the cam to work
against to drive back the shovel until released, when the spring sends it forward
with requisite force, and projects the fuel onto the fire.
"
The shape of the shovel is such that it tends to scatter the fuel, and may consist
of any suitable section of a circle or of sides at an angle to each other, and the top
is generally bent back for a short distance so as to close the orifice to the crusher or
feeding box when the shovel is beyond the said orifice. In many cases I box in
the side of the shovel to prevent the fuel getting behind it.
The lever is rounded on that part where the spring presses against it, so as to
roll upon the spring and be practically noiseless. The spring is made by pre-
ference of flat plates of steel, which may have small rollers between to prevent
friction, and which press upon the rounded back of the lever, and is supported
in any convenient manner, but usually in a recess placed or cast on the side of
the crusher box; but other forms of spring may be used, such as a clock or a coiled
spring, adapted to produce a similar result either by having the end flat and
bearing on the lever, as described for the plates of steel, or by having a buffer
placed between the spring and the lever, or other convenient modes of attaining
the same end.
The cam which actuates the throwing apparatus is placed upon the crusher
shaft, and preferably consists of a cam plate with 5 or 6 studs upon it arranged
in any convenient manner, but usually on the face next the crusher box.
Important advantages are gained by the simple plan of making the shovel work
on the end of a lever, as described, for without deepening the shovel box the shovel
can take a much longer sweep and can be made much lighter than a solid shovel
attached to a shaft. The longer sweep ensures when properly utilized a nearly
perfect distribution of the fuel.
The working parts of the machine are very much reduced in number, a most
important gain in this class of machinery.
For some classes of furnaces a single hopper is made use of to feed two fires,
which hopper is placed in the centre, and the crusher is directly underneath; the
fuel is fed by means of a worm or wings like those of a pug mill, and there is
a contrivance just above the feeding box to ensure regularity in the feed to the
shovel.
The throwing apparatus is supported by the tube through which the fuel passes,
though castings.might of course be placed upon the front for this purpose, but this
would not be so simple.
To break up the clinker and to give the fuel a progressive motion, bars similar
to those described and claimed in Letters Patent, No. 3070, of 1878, are used, but
the projection on the bar is placed in the centre, against which the loose cam works,

page_text: giving greater steadiness to the bar, and a support is placed under the bars just
behind the groove in which the cam works.
For a like purpose a cast iron or steel bar is used having a groove on the top
running lengthways, and over this is placed a bar of square wrought iron made with
a rib to fit into the groove. A few rivets are then driven through to keep the wrought
iron in its place, but in such a manner as to allow of expansion and contraction
lengthways.
For a like purpose bars made of cast steel are used with an arrangement to keep
them relatively cool.
Sometimes the bars are arranged so that the whole or a portion of them rise up
as they go forward and fall as they return, or some rise and fall and others move
backward and forward.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Bennis in the Great Seal Patent Office on the 27th February
1880.
EDWARD BENNIS, of Bolton, in the County of Lancaster. "IMPROVEMENTS IN
FURNACES FOR STEAM BOILERS AND OTHER STRUCTURES, AND IN APPARATUS FOR
FEEDING THEM WITH FUEL."
Fig. 1 is a front elevation of my machine partly in section; Fig. 2, a side eleva-
tion partly in section; Fig. 3, an elevation partly in section showing crusher and
feed regulator H; Fig. 4, view of cams for actuating the bars; Fig. 5, plan of bar
looking from below showing slot in which the washer cam O fits closely and works;
Fig. 6, enlarged view of crusher I; Fig. 7 shows general construction of my
machine; Fig. 8, view showing the application of my present improvements to my
former Patent.
This Invention consists in constructing a machine with the ordinary hopper A
opening into a crusher chamber or crusher box B, or into a feeding box, on which
box ribs may be cast or fixed to guide the fuel, prevent its return, and assist in
breaking up any lumps, or such ribs might be upon a crusher plate placed inside the
box B.
On the shaft E running through this box or chamber is placed the crusher I, con-
sisting generally of cast iron or cast steel stars or chambered discs having as many
chambers as there are throws of the shovel to each revolution of the shaft, thus sup-
plying the fuel in front of the shovel at any desired point of its movement, obviating
any danger of fuel getting to the back of the shovel; but though this is the best
arrangement of crusher and feeder for my machine, I do not limit myself to it, for I
could use a different number of chambers, as, for instance, if two such chambers
passed between one throw of the shovel.
In the crusher box B may be placed two regulators H, K, to control the supply of
fuel to the shovel box L, one of which can completely or nearly completely close the

page_text: opening into the shovel box, and the other a plate K, which controls the supply
before it enters the crusher, by which combination the fireman or engineer obtains
complete control of the supply, and that irregularity which has been an objection to
mechanically fed furnaces done away.
On the last named regulator teeth may be cast, which when this crusher is closed
pass between the star crushers and clear the coal away in a simple and effective
manner, thus preventing the crusher from becoming choked when the fuel is damp..
The opening into the crusher box is so arranged that when the bottom regulator H
is quite closed the fuel simply fills the chambers in the crushers and revolves with
them, and the apparatus does not choke itself, as would be the case with those in
common use if the oxit from the crusher or feeder were closed.
Under the crusher or feeding box B is placed a box L for the shovel M to work in,
the contour of the bottom and top of which forms part of the circumference of a
circle having the same centre as the arm on which the shovel moves.
This shovel
box has parallel sides to within a short distance of the boiler front or the front of the
shovel box, where they gradually diverge; the distance may be varied according to
the breadth of the furnace.
The throwing or distributing apparatus moves in the arc of a circle, and consists
of a lever C hung upon a stud or shaft which forms a centre, and which stud or
shaft is supported preferably by a casting on the side of the crusher box; and
attached to the lever C there is a plate M, which nearly fills up the interior section
of the shovel box, having sufficient room to swing freely therein. This lever is
usually hung just above the crusher shaft E, or a little to the front or back of it, as
needed for various furnaces, and the lever is bent in such a manner as to clear the
crusher shaft and any other projection, and to enable the cams to operate upon it,
and to enable it to enter the shovel box L at the side, top, or back, as may be con-
venient. To the end of this lever C the shovel M is attached in any suitable
manner, or it may be formed in one piece with the lever. On a suitable part of the
lever is placed a projection or stud for the cam D to work against to drive back
the shovel until released, when the spring sends it forward with the requisite force,
and projects the fuel on to the fire. The shape of the shovel is such that it tends
to scatter the fuel, and may consist of any suitable section of a circle or of sides at
an angle to each other; and the top is generally bent back for a short distance so as
to close the orifice to the crusher or feeding box B when the shovel M is beyond the
said orifice. In many cases I box in the side of the shovel as a further precaution
against the fuel. getting behind the shovel. The lever C is rounded on that part
where the spring F presses against it, so as to roll-upon the spring and be practically
noiseless.
: The spring F is made by preference of flat. plates of steel, which may have small
rollers between to prevent friction, and which press on the rounded back of the
shovel arm or. lever C, and is supported in any convenient manner, but usually in a
recess placed or cast on the side of the crusher box B; but other forms of spring
may be used, such as a clock or coiled spring, adapted. to. produce a similar result
either by having the end flat and bearing on the lever, as described for the plates of
steel, or by having a buffer placed between the spring and the lever, or other con-
venient modes of attaining the same end.. One such mode I describe. Instead, for
instance, of the flat plates, a bell-crank lever might be used, one end of which would
be flat and press upon the shovel lever, as described for the flat springs, the other
end being attached to a coil or other suitable spring; the result would be very.
nearly the same, though it will be seen that it would not be so simple. In many
cases I find it a convenient plan to attach a coiled spring G to a pin at or near the
opposite end of the lever from the shovel, which coiled spring is drawn into tension.
as the shovel is driven back by the cam D, and supplies the power which throws
the fuel into the fire, while the flat spring or its equivalent acts as the buffer when
the shovel has reached the point where the fuel has been struck. It will be seen
that in the combination last named, and which I find in practice to act exceedingly
well, nearly all the friction is avoided, and an almost silent action of the machine.

page_text: attained, while the shock to the machine which takes place when an india-
rubber buffer is struck is dispensed with, as the arm of the shovel may always.
be in contact with the buffer, and there is no passage through mid-air before
striking the buffer.
The cam D which pushes back the throwing apparatus or shovel arın is placed upon
the crusher shaft, and preferably consists of a cami plate with 5 or 6 studs upon it
arranged in any convenient manner, but usually on the face next to the crusher
box B; these studs or cams press directly on the shovel arm stud already described,
and as shown in the Drawings, driving out the arm and placing the spring in ten-
sion or compression, as the case may be, until the can releases the arm, when the
shovel flies forward, and striking the coal scatters it over the surface of the fire.
Important advantages are gained by the simple plan of making the shovel work
on the end of a lever, as described, for without deepening the shovel box L the
shovel M can take a much longer sweep and can be made much lighter than a solid.
shovel attached to a shaft. The longer sweep ensures when properly utilized a
nearly perfect distribution of fuel. The working parts of the machine are greatly
reduced in number, and are much more durable, two important gains in this class of
machine. Another most important gain is made by hanging the shovel upon the
side of the crusher box, as all intermediate parts are done away with, though it is
obvious that an attempt might be made to attain the object of my Invention by
carrying out a shaft from the shovel of a machine made on the old plan, and placing
a cam on a crusher shaft similarly lengthened out, and so doing away with the up-
right cam shafts, worms, and wheels, et cetera, but this I would regard as an
infringement of my Invention; or by using a shovel like the old plan and placing
or casting a stud thereon for a cam to work against, and placing a cam upon a
crusher shaft lengthened out for the purpose, some of my advantages might be
gained, but this also I would regard as an infringement of my Patent, and would be"
simply a variation of the method of application, but dispensing with part of my
Invention and advantage gained.
For some classes of furnaces a single hopper is made use of to feed two fires (see
Fig. 8), which hopper is placed near the centre, with the crusher directly under-
neath. Fuel is fed by means of a worm or wings like those of a pug mill, and there
is a contrivance just above the feeding box to ensure regularity of feed to the shovel.
The throwing apparatus, already described, is supported on the tube through which
the fuel passes to the shovel box, though castings might of course be placed upon
the front for this purpose, though this would not be simple.
. To break up the clinker and to give the fuel a progressive motion, bars similar
to those described and claimed in Letters Patent, No. 3070, of 1878, are used, but
the projection on the bar is placed in the centre, against which the loose cam works,
giving greater steadiness to the bar, and a support is placed just behind the groove
in which the cam works. These bars are all driven forward together by the cam cast
or fastened on the shaft, and then brought out in sets by the washer cams O, which
work against a pin cast or placed in a slot left in the bar for the purpose. This
slot keeps the washer cam O in its place, and is hollow to the back to allow said
cam to pass freely round until in position to draw out the bar. By placing these
cams one behind the other on the shaft S (see Fig. 4), the bars are drawn out in sets
of 3, 4, 5, or more, as may be desirable. It is manifest that the cams on the shaft and
the washers might be easily applied so as to reverse the action and draw out the
bars all together, driving them in in sets.
To allow of a freer admission of air than has hitherto been attained with bars of
this description, there is an incline placed upon the bar at the back or front, or both,
which causes all the bars to rise up as they go forward, and then the returning bars
slip out of the fire, allowing the free admission of air to the clinker, cooling and
cracking it, while the bar is not injured as it is in the description of moving bar in
which part of the bars rise up forcing their way into an intensely hot fire. To
prevent these bars burning out by the intense heat created, a cast iron or steel bar
is used, having a groove on the top running lengthways. For a like purpose bars of

page_text: cast steel are used, with an arrangement to keep them relatively cool. Sometimes
the bars are arranged so that the whole or a portion of them rise up as they go
forward and fall as they return, or some rise and fall and others move backward
and forward, but these motions endanger the stability of the bar, and are only
applicable to some classes of fuel. Over the groove in the cast iron or steel bar
is placed a bar of square wrought iron made with a rib to fit in the groove; a few
rivets are then driven through to keep the wrought iron in its place, but in such
a manner as to allow of expansion lengthways. It need not run the whole length
of the bar.
Having now described my Invention and the best mode known to me of carrying
it into effect, I wish it to be understood that what I believe to be new and desire to
protect under the hereinbefore in part recited Letters Patent is,-
1. Manufacturing or using mechanical stokers with the arm or lever carrying the
shovel or its equivalent placed at one side of the crusher box, and drawn back
against the pressure of the spring by means of cams or their equivalent on the
crusher shaft or its equivalent, substantially as and for the purposes described.
2. In mechanical stoker machines, the tappet plate D with pins or tappets upon
it placed upon the crusher shaft or its equivalent, and working directly upon the
shovel arm or lever or its equivalent, substantially as described.
3. The manufacture and use in mechanical stoker machines of the curved or bent
lever C.or its equivalent, substantially as and for the purposes described.
4. The special apparatus for regulating the supply of fuel to the shovel, substan
tially as described.
5. The arrangement of springs in mechanical stokers in which one spring actuates
the shovel or its equivalent, and the other acts as a buffer in such a manner that it'
will always bear on or be close against.or to the moving mechanism without mate-
rially counteracting the effect of the other spring until the fuel has been struck, and
consequently gradually take up the rebound, instead of the shovel apparatus coming
violently against it, as in ordinary buffers.
6. The improvements in detail, substantially as herein described, on the fire bars
and the mechanism for actuating the furnace, set forth in the Specification and
Drawings of my former Patent, No. 3070, of 1878.
7. The arrangement of mechanical stokers or apparatus for supplying fuel to
furnaces, substantially as described and shown.
In witness whereof, I, the said Edward Bennis, have hereunto set my hand and
seal, this Twenty sixth day of February, in the year of our Lord One thousand
eight hundred and eighty.
GEORGE MASON,
Engineer,
101, Bury New' Road,
Bolton.
EDWARD BENNIS. (L.S.)