IMPROVEMENTS IN AND APPERTAINING TO BOILER AND OTHER FURNACES AND TO SUPPLYING FUEL TO THE SAME, AND IN APPARATUS THEREFOR."
Year: 1878

page_text: LETTERS PATENT to Edward Bennis, of Bolton, in the County of Lancaster,
56
Engineer, for the Invention of IMPROVEMENTS IN AND APPERTAINING TO
BOILER AND OTHER FURNACES AND TO SUPPLYING FUEL TO THE SAME, AND IN
APPARATUS THEREFOR."
Sealed the 31st January 1879, and dated the 3rd August 1878.
PROVISIONAL SPECIFICATION left by the said Edward Bennis at the Office
of the Commissioners of Patents on the 3rd August 1878.
EDWARD BENNIS, of Bolton, in the County of Lancaster, Engineer. "IMPROVE-,
MENTS IN AND APPERTAINING TO BOILER AND OTHER FURNACES AND TO SUPPLYING
FUEL TO THE SAME, AND IN APPARATUS THEREFOR."
This Invention consists chiefly in improvements on my former Patent No. 1308,
of 1875, and in furnaces to be worked with the same.. It consists,―
First. In shaping the shovel with a series of radial planes on it to more effectually.
scatter the fuel.
2. Arranging the springs, one or more to each flue, so that in a double or treble
flue boiler one spring can be compressed more than another alternately, and con-
sequently one flue fed more than another at one time, or each flue be fed alternately; '
the same thing applies to two sides or corners of the same flue. The springs are
placed in a recess beneath the shovel when convenient.
3. I also extend the crusher plate beyond the vertical centre line of the crusher.
to prevent the small coal from running through.
4. The construction of a revolving crusher with a series of beaks pointing in the
direction of the throw.
5. Where two flue boilers are used I employ a reciprocating or swinging crusher,
reciprocating or swinging between the two flues, the crusher and flues being cach
armed with teeth so as to distribute and crush the coal from one hopper into both
throwing apparatus.

page_text: 6. For the same purpose a revolving crusher, with a screw at each side like that
described in the Specification 3017 of 1870, can be used; the bearing can be self-
-adjusting. Also, I sometimes use a plate crusher to work in the middle of the
screw worked by cams.
.
7. I sometimes arrange a shovel with two or more steps on it of varying shapes.
8. To scatter the fuel evenly over the fire I may vary the convolutions of the
shovel or shape the front of the shovel box top or bottom for the purpose; or I
use a separate distributing plate, sometimes made moveable and sometimes
stationary, according to the shape of the furnace, and also by directing the throwing
box of a spring machine in such a manner as to throw on the centre point of the
furnace or nearly so; also by causing the shovel or throwing apparatus to turn on
a centre, so as to face various points of the fire at different times, the same effect
(that of comparatively even feeding) may be gained.
I sometimes place the throwing apparatus when actuated by the rebound of a
spring at the side of or on the furnace door, by which means I lower the hopper
into which the coal is thrown, and also by the employment of which in combination
with a vertical crusher I am enabled to feed two flues with the one hopper and
crusher.
My improvements in that class of stoker, in which a revolving beater or beaters
throw the fuel on to the fire, consist in placing the beater or beaters at the side of
the furnace door instead of above it.
9. In an arrangement of self-cleaning fire-bars; these are alternately moveable
and stationary. The moveable ones are supported on a shaft at one end, so as to
rotate uniformly. This shaft has a cam under each moveable bar working in a
peculiarly shaped projection on the bottom of the bars. The bars are so arranged
that the cam projects them upon an inclined plane, and when it leaves them the
bars slide down. For this purpose a roller is or can be used, and the incline can
be on the bars. The bars move forward at the highest portion of the throw inter-
mittently. When the stationary bars are hollow for conveying air I convey that
air into the chamber behind the fire, and sometimes place a loose rod in it so that
by moving the rod by hand or machinery the passage is kept clear. Sometimes I
make the moveable bars hollow in this way.
In steamers especially fire-bars are apt to stick to each other, or rather rest on
each other, so as to prevent movement. To prevent this I construct the stationary
bars with projecting distance pieces touching each other, and also place small
friction spheres between each bar, so that the moveable bars may move on them
instead of rubbing against the stationary bars. The bars are grooved to hold the
spheres. In feeding I feed on to 1/2 or 3% of the bar and not all over. The motion
of the bars covers the remaining portion.
I sometimes arrange the furnace so that the moveable bars at the sides move
together and the central portion at an alternate interval.
I also use a special arrangement of fire-bars in which all the bars go forward
together so as to carry the fire with them, and are brought back by the same cam
that drives them forward by an alteration in the shape of the bar where the cam
works on it to push it back.
I sometimes cause two, three, or more of the bars to rise up as they move
forward, and to fall as they move back to the ordinary level by which the clinker
is more effectually broken up.
I sometimes use the shaft that drives the fire-bars to actuate the throwing.
apparatus, thus having only one shaft to do all the work on the front of the

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Bennis in the Great Seal Patent Office on the 3rd February
1879.
EDWARD BENNIS, of Bolton, in the County of Lancaster, Engineer. " IMPROVE-
MENTS IN AND APPERTAINING TO BOILER AND OTHER FURNACES AND TO SUPPLYING
FUEL TO THE SAME, AND IN APPARATUS THEREFOR."
My Invention relates to improvements on my former Patent No. 1308 of 1875,
and in furnaces to be worked with the same, and consists chiefly in the use, as
herein-after more particularly described with the aid of Drawings, of improved
methods of feeding fuel by means of throwers actuated by springs and placed in
very advantageous positions, and also in the use of improved fire-bars, as herein-
after described. In that form of mechanical stoker (so called) in which the object
is to scatter the fuel over the surface of the fire by a motion caused by the action
of a spring or similar motion, it is usual to place the throwing apparatus (whether
consisting of a single shovel or two smaller ones a little apart) directly over the
furnace door, as shewn in my Patent No. 1308 of 1875.
The large portion of the boiler front covered by machines so arranged, leaving.
but little room for the steam and water guages, which are thereby also thrown into
a shade and apt to deceive the attendant and the liability to get out of order
from the multiplication of working parts, together with the great height of the
hopper into which the fuel has to be thrown has operated materially to hinder the
universal adoption of mechanical stoking. I find, however, that by using a properly
constructed shovel and shovel box in the manner herein-after described, I can feed
the fuel at a lower point and make one hopper and one crushing and feeding
apparatus answer a double purpose, thus reducing the cost of the machine and
simplyfying its parts while considerably reducing the portion of the boiler front
covered by the stoker. This I affect mainly,-
First. By a proper adjustment of convolutions or radial planes on the shovel.
Second. By shaping the front of the shovel box top or bottom as convenient.
Third. By directing the shovel so that its movement shall be toward the central
point of the furnace, or nearly so.
Fourth. By the use of a distributing plate generally made moveable, but which
may be used in a fixed position in some cases.
Fifth. By causing the throwing apparatus to turn on a centre and face various
points of the furnace in rotation.
Sixth. By using a shovel made with steps upon it, so that at each throw varying
parts of the furnace will be covered.
Seventh. By supporting the shovel at one end and giving it a rotary upward*
motion round a portion of the said support.
The shovel may with advantage be divided like a honeycomb or into chambers,
one above another, the higher ones manifestly throwing further than the lower
ones. I place the shovel box on the furnace front at one side of the door, in some
cases having the door as ordinarily placed, but where the front is too contracted
for this I move the door nearer to the opposite side of the flue. The shovel box is
thus but a few inches above the dead plate, or in some cases partly below its level,
and protruding into the space usually occupied by the dead plate; this latter point
is more especially applicable to marine boilers where saving of room or space is of
very great importance. The two shovel boxes being thus brought nearer together-
can easily be fed from one hopper, and the height to which the fuel is thrown
reduced from twelve to eighteen inches.
It will be manifest that other and analogous modes of attaining some of the
objects of this Invention may be substituted; for instance, a machine driven by a
spring may be placed on one side of a double door, the side on which the machine
is placed not being generally used; or the machine might be placed on the ordinary

page_text: door, the simplicity of the driving required enabling it to work with success, where
beater machines have failed through the necessarily complicated driving, &c. Or
such a machine might be placed at a furnace mouth, with the hopper directly above
it and a small furnace door on one side or both sides of it; but these modes would
be in many cases less advantageous modes of attaining some of the objects of my
Invention, such as lowering the hopper, &c.
It is not proposed to use all the modifications of the shovel above described in
any one machine, but select from them such as are suitable to be used alone or in
combination in case it may be found desirable.
In general it will be found the form of attachment between the shovel and
spring, shewn in the Drawing, may be most advantageously used, in that the
shovel is a lever supported on a pin, though it is obvious it might be supported
on centres or attached to a rocking shaft; the upper part above and below the pin
is a sector of a large circle, and the spring is flat; when the lever or shovel is pressed
out it pushes back the spring with a rolling motion, and when released it rebounds
back again, and the same spring acts as a buffer when a certain point is passed.
By this means great simplicity is attained, and the stops and india-rubber buffers,
which are a source of continual trouble, are all dispensed with. In this arrangement
the force of throw is increased by lowering the spring and decreased by raising the
same..
It will however be seen that other forms might be used, the circle might be
upon the spring and the lever flat, or both may be sectors of a still larger circle ;
some of the advantages secured by this arrangement may be gained by analogous
plans. In illustration of this I may mention that a spiral spring working on a
pin, to which it is attached at one end and itself attached to the shovel at the
other, would act in a similar manner, but the strength of the spring could not be
so easily adjusted.
In one of my arrangements of self-cleaning, fire-bars are alternately moveable and
stationary, the moveable bars are supported by a shaft near one end which has a
cam running the whole length, and working in a jaw of a peculiar shape, as sub-
stantially described on the Drawings.
+
In another of my arrangements of self-cleaning fire-bars all the bars are driven.
forward together by a cam working in a jaw of peculiar shape, and can be brought
back by the action of the same cam that drives them forward singly or in sets,
depending upon the form of the aforesaid peculiar jaw, or by a cam placed upon a
washer placed upon the cam shaft already named, and working against a projection
on one or both sides of the bar. It will be seen that in this case one cam shaft
does all the work usually performed by two or three.
I sometimes use the shaft that drives the fire-bars to actuate the throwing,
crushing, and feeding apparatus, thus having only one shaft on the front of the
boiler.
In steam vessels especially fire-bars are apt to rest upon each other sideways,
so as to impede the movement; to prevent this I use small friction spheres, or
their equivalent, working in grooves placed between the bars; the use of these
friction spheres constitutes an important part of my Invention so far as it relates'
to fire-bars.
In order to crush and distribute the fuel to the two flues from one hopper I use a
crusher directly under the hopper, with teeth and cutters like those shown on the
Drawing, by which it will be seen that the coal is forced forward in front of the
teeth, thus insuring a regular supply to the distributers just outside the crusher.
I place upon the same shaft either one or more wings like the blades of a pug mill
to push forward the fuel until it falls into the distributing chamber; or for the
latter purpose I sometimes use a screw constructed with a continually increasing
space between the threads, which prevents the coal from jamming itself.
I usually make the crusher plate approach the shaft more nearly at its centre
and widened towards the aforesaid blades, in this respect being like a single or
double coffee mill..

page_text: I do not confine myself to the exact details given, though the plan described is
the one I prefer.
I find that by a proper adjustment of the beaters and of the ribs placed on
beaters of the well-known "Stanley" type, as described in his Patent No. 4692
of 1822, I can gain many of the same advantages attained with the shovel machine,
as already described. This I accomplish in the following manner:-I place the
beater box at the side of the furnace door in some cases, however, so low down that
the upper portion of the beater is only two inches higher than the dead plate, and
sometimes I form a recess in the dead plate near the side of the furnace in which
the beater is placed. I sometimes incline this beater so that its motion is towards
the central point of the furnace or nearly so. I so arrange that the fuel falls upon
the beater before it attains the highest point in its revolution. I place upon the
said beater ribs or short blades at various angles, so as to distribute the coal
uniformally over the fire.
To utilize the horizontal form of the "Stanley" beater I place the same as
before at the side of the furnace, and place upon it ribs at various angles, and some
of them so placed as to throw the fuel upwards and forwards, as shown in the
Drawings.
My Invention will be fully understood by reference to the accompanying
Drawings, where the principal parts are already indicated and their method of
action is illustrated.
A is the hopper in which the fuel is placed; B are the revolving crusher blades;
C are the stationary cutting blades; D are the pug mill blades which pass the
fuel to the shovel box E in which the shovel F works; G is the spring working
the shovel, as already described; H, H, are the furnace doors; I is the shaft which
drives the machine; K, K, are the fire-bars which all move forward together,
substantially described; L', L2, L3, L4, are the variations in space, by which the
bars are brought back separately or in sets of not more than '/rd of the total
number; M is the washer which may be substituted for the varying spaces in the
jaw; N is the shovel giving the rotary upward motion; O is the shaft with the
cam P cast upon it for working the bars; R is the peculiar shaped jaw; S, S, are
the spheres on the bars; T. T, are the beaters; U, U, are the short blades or ribs
on the beaters.
Having thus stated the nature of my Invention and described the modes of
performing the same, I wish to remark that I do not intend to limit myself to the
exact details given, as in some cases. the same may be varied according to the
peculiar construction of the boilers and furnaces to which the improvements may
be applied, but that what I claim and desire to be secured to me by the herein-
before in part recited Letters Patent is,-
First. Constructing or using mechanical stokers which throw the fuel over the
surface of the fire with the distributing apparatus placed at one side, or wholly or
partially where the dead plate usually is instead of above the door as usually has
been the custom, for the purposes and substantially in the manner described.
Second. The use, substantially in the manner described, of the distributing
apparatus such as herein referred to, for the purpose of giving a uniform distribution
when the distributing apparatus is not placed in the centre line of the flue.
Third. The combination of a central crusher, containing teeth blades or ridges
with a screw or blades to distribute the fuel at one or both sides, substantially as
described.
Fourth. The use of a spring which forms its own buffer, as described, when used
in connection with a shovel or lever acting upon a shovel hung upon a centre or
pin or attached to a rocking shaft, substantially as herein described.
Fifth. The use of beaters constructed and applied as described for the purposes
mentioned, and substantially as shown on the Drawings.
Sixth. The use of friction spheres, or their equivalent, in connection with
mechanically moving bars, for the purpose and substantially as herein described.
Seventh. The general arrangement of fire-bars, by which they are made to act

page_text: as self-cleaning surfaces in such manner that all the bars are moved forward
together, or are brought back separately or in sets by the same shaft and cam that
drives them forward, or by separate washer cams placed upon the cam shaft, sub-
stantially as herein described.
Eighth. The combination of my herein-before described self-cleaning bars, which
move the fuel from the place where it falls, with, a throwing apparatus placed at
one side of the furnace front or where the dead plate is, substantially in the manner
and for the purposes described.
In witness whereof, I, the said Edward Bennis, have hereunto set my hand
and seal, this First day of February, in the year of our Lord One thousand
eight hundred and seventy-nine.
Witness;
EDMUND CHADWICK,
Patent Agent,
30, Arrowsmith Terrace,
Bolton.
EDWARD BENNIS. (L.S.)