IMPROVEMENTS IN FURNACES FOR STEAM BOILERS AND OTHER STRUCTURES AND IN APPARATUS FOR FEEDING THEM WITH FUEL"
Year: 1882

page_text: LETTERS PATENT to Edward Bennis of Bolton in the county of Lancaster
for an Invention of "IMPROVEMENTS IN FURNACES FOR STEAM BOILERS AND
OTHER STRUCTURES AND IN APPARATUS FOR FEEDING THEM WITH FUEL"
PROVISIONAL SPECIFICATION left by the said Edward Bonnis at the Office
of the Commissioners of Patents on the 20th December 1882.
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
"
First in constructing the feeding apparatus in an extremely simple manner so
that ordinary iron nails, bolts, or hard lumps of coal or shale pass through without
interfering with the apparatus this I attain by the employment of a pusher
generally actuated from the same shaft that actuates the throwing apparatus by.
means of a lever arranged in such a manner with a slot or otherwise that the length
can be shortened or lengthened as more or less coal is required to be fed each
stroke, or the same end I may attain by regulating the connecting link between
the pusher & lever, or by other convenient method-avoiding thereby the use of.
more than one shaft to work the feeding part of the machine.
This pusher may be used to push the coal to the side or from the front as
desirable in particular cases, but for general uso I prefer pushing from the front
Secondly In improved construction and shape of shovel and shovel arms-wheroby
a better distribution of the fuel is secured.
The throwing apparatus which I generally use consists of a shovel by preference
of steel attached to a shovel arm hung upon a centre or rocking shaft The shovel
is preferably rounded in the front so as effectually to scatter the fuel-working in
a throwing box also so shaped as to produce a like effect that is with the central.
portion of the front raised and the sides depressed so as to guide the fuel to the
side of the furnace. This raised portion I prefer to have cast separately and

page_text: attached to the shovel box in such a way that it can be moved to either side so as
to alter the distribution as may be required.
Thirdly In the construction of fire bars in the form of a bridge with or without
air space in the centre for the purpose of driving air along the centre part by
means of a steam jet-so as to keep the bars cool and chill the clinker-the steam
not being applied to the space between the bars themselves.
I would have it understood that I do not blow steam into the fire-such a
practice being in my judgment injurious
Fourthly I construct the fire bars of a peculiar shape on the surface-the part
near the front end rising as it goes forward for a foot or so and then sloping
downwards to within 10 to 15 inches of the other end from which point I construct
them with a slight rise or in some cases quite straight, the object attained by this
form of bar being that the fire does not leave the front end too rapidly-while it
travels more quickly after the bar slopes down, but as the bar slopes upward at the
far end the clinker does not leave the bar too rapidly and thereby prevents the bar
from becoming uncovered which has been a great fault in self cleaning bars
The bar is generally cast in 2 parallel sections with an air space between, and a
hollow space under this air space along which air will pass by the ordinary draft
when the draft is good but along which I blow air by a steam jet or other means
when the draft is bad so as effectually to chill the clinker and keep the bars cool
thus preventing the burning of the fire bars (one of the great difficulties hitherto
experienced with self cleaning bars) When I cause the clinker and fire to move
from the back of the furnace to the front-I sometimes cast the bara hollow
without the air-space and cause air to pass through the bars to a hollow bridge,
and so with the combustion chamber entirely preventing smoke
In this case I also use a slightly different method of driving the bars, namely I
arrange that the bars shall move up an incline in going into the furnace one by
one being driven in by cams situated on the driving shaft-while in coming to the
front they are drawn either by the cam shaft as described in my former patent
(N°. 3443 of 1879) or they may be all joined together by a rod run through a slot
in the bars and drawn back by the movement of two or more of the bars or by
the direct action of a cam on the rod as desirable in various classes of furnace.
This method of driving can also be employed to drive bars working the
reverse way.
Fifthly I find that for marine boilers it is better to throw the fuel to the end of
the bars by reversing the action of the fire bar, as described in the Specification of
my former patent to cause the clinker to travel to the front of the fire where I
cause it to accumulate on or near the dead plate or to be deposited on the flue
bottom, or into a receptacle in front of the furnace.
I also sometimes cast very large air spaces near the front end so as to allow
pieces of clinker and ash to fall through that the air may chill the clinker before
it is taken from the furnace by hand or by machine
This plan can be adopted also with fan machines
In some cases I use a bridge
which overhangs the bars at the back end and cause the fuel to move from the
back to front as described in the next paragraph such bridge being constructed so
as to admit air to the bar ends to keep them cool which air being heated from the
bars passes into the furnace behind the bridge.
In these cases I generally use a dead plate or iron door suspended from such
bridge or moving freely in it to keep the fuel from getting underneath the bridge
I modify my bars when I use them to bring the coal from the bridge end to the
front by doing away with the hack dead plate and placing a bridge of peculiar
construction over the end but not touching I may use an ordinary beater to
distribute the fuel in combination with my new feed motion but I prefer for general
uso the shovel and spring. I sometimes place the cam which actuates the spring
and also the cam which actuates the feeding apparatus on the bar shaft, and so do
away with any shaft in front of the boiler except the one.
Sixthly I make the front of the feeding box nearly open so that by removing.

page_text: the plate which is placed as a cover thereon the pusher can be removed and the
whole arrangement be open-a valuable point in case any piece of iron or other
material gets in too large to go through, and too hard to crush.
Seventhly In the box I place a plate which rests on the shaft that drives the
machine on which shaft I have one or more projections that lift this plate and let
it drop again—thus disturbing the fuel in the hopper-a rod being attached to the
plate that projects upward into the fuell like a T preventing the commonly known
tendency to arch in fuel so fed.
Eighthly I also sometimes use what is called a chain bar made of wrought iron
steel or cast iron in which the bars run at right angles to the flue or are made in
very short lengths and with projections on them by which they are fastened
together in such a manner that they cannot easily get out of place-these bars
when made to go across the flue are made of shorter length than the whole distance
between the side bars. In some boilers however it is preferable to arrange them
longitudinally and in such case I prefer them to override the side or stationary
bars the latter as well as the edges of the chain bars being bevelled. This allows
for expansion. I sometimes also prefer to arrange so that one chain of bars move
at a greater speed than its neighbour so that the clinker becomes broken up-this
applies to bars running in the same direction as flue

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 20th June
1883.
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 is an improvement on that for which I have obtained Letters
Patent No 1308 of 1875, N° 3070 of 1878, N° 4360 of 1878, and N° 3443 of 1879.
Firstly. I construct the feeding apparatus in an extremely simple manner, so
that ordinary iron nails, bolts, or hard lumps of coal or shale, pass through without
interfering with the apparatus; this I attain by the employment of a pusher A,
which I prefer, as a rule, to actuato from the same shaft that actuates the throwing
apparatus, by means of a lever arranged in such a manner, with a slot or otherwiso,
that the length of movement can be shortened or lengthened as more or less coal is
required to be fed each stroke, or the same end I may attain by regulating the
connecting link between the pusher and lever, avoiding thereby the use of more
than one shaft to work the feeding part of the machine.
The arrangement I find best in practice in those boilers where there are two
furnaces is as follows-see Figs 1 Plan, and 2 Elevation, of double machine.
A is tho pusher actuated by the lever B, which in turn is moved forward to feed
the fuel by the cam C, and brought back by the action of the rod D, which passes
between the two levers, and connects them being linked into slot E, which is
provided with counter sunk depressions for the bolt head F, or the rod can have no
slot but a series of corresponding holes.
By moving the rod D along the slot E in the lever B, the travel of pusher A is
regulated, and the quantity of fuel fed is increased or decreased as mnay bo
required. A very great advantage is gained by the perfect control thus given
over the quantity fed to each fire separately.
In furnaces where there is only one fire to feed, I use a cam with two sides as
shown in Fig 3, and regulate the fuol by opening or closing the space G.
I sometimes find it convenient to cast the opening in the pusher rather too
wide, and put a screw at Z to regulate the feed-when screwed in this increases
the movement, and when unscrewed it decreases the quantity fed.
This pusher may be used to push the coal to the side or from the front, as
desirable in particular cases, but for general use I prefer pushing from the front.
Secondly an improved construction and shape of shovel and shovel arms,
whereby a better distribution of the fuel is secured.
The shovel arm H I construct as shown with a section of a circle on the back
part. On this shovel arm the lever K presses. This is also constructed with the
part that rests on the shovel arm, the section of a circle cut of somewhat larger
diameter. The lever K I pivot on a point as near as practicable to the versed sine
produced of the arc of motion of the shovel arm-as set forth in drawing.
To this arrangement I attach very great importance, securing as it does the best
result with a very small amount of friction, and enormously reducing the loss of
the applied power and so increasing the life of every part of the arrangement.
The throwing apparatus which I generally use, consists of a shovel I by
preference of steel, attached to a shovel arın H hung upon a centre or rocking
shaft. The shovel is preferably rounded in the front, so as effectually to scatter
the fuel as set forth in my previous patents, but working in a throwing box also so
shaped as to produce a like effect, that is with the central portion of the front
raised, and the sides depressed, so as to guide the fuel to the side of the furnace.

page_text: This raised portion I prefer to have cast separately, and attached to the shovel box
in such a way that it can be moved to either side, so as to alter the distribution as
may be required.
Thirdly. In the construction of fire bars in the form of a bridge, with or without
air space in the centre, for the purpose of driving air along the centre part by
means of a steam jet, so as to keep the bars cool and chill the clinker, the steam
not being applied to the space between the bars themselves, and I sometimes put
openings G into the hollow part for the air to escape into the furnace, as set forth
on clause 4 of my provisional Specification, but as a rule I prefer not to use these
openings.
I would have it understood that I do not blow steam into the fire, such a
practico being in my judgment injurious. This arrangement is shown in Fig. 6, in
which A is a portion of the bar formed in bridge section, and B end entirely bridged
over so as to form a hole, the air enters at the part not entirely bridged over and the
jet C blows the air along and keeps the bar cool. I sometimes add a second jet D
near the fully bridged portion, to enable the air the casier to enter the hole. But
in no case do I introduce a steain jet into the fire, such action though very common
being positively injurious.
Fourthly. I construct the upper surface of the fire bars of a peculiar shape, the
part near the front end rising as it goes forward for a foot or so and then sloping
downwards to within 10 to 15 inches of the other end, from which point I con-
struct them with a slight rise, or in some cases quite straight, the object attained
by this form of bar being that the fire does not leave the front end too rapidly-
while it travels more quickly after the bar slopes down, but as the bar slopes
upward at the far end, the clinker does not leave the bar too rapidly, and thereby
prevents the bar from becoming uncovered, which has been a great fault in self
cleaning bars. Fig 6 shows the form I have found most useful for general
purposes.
The bar is generally cast in two parallel sections with an air space between, and
a hollow space under this air space, along which air will pass by the ordinary
draft when the draft is good, but along which I blow air by a steam jet or other
means when the draft is bad, as set forth in part 3, so as effectually to chill the
clinker and keep the bars cool, thus preventing the burning of the fire bars, (one of
the great difficulties hitherto experienced with self cleaning bars).
Fifthly. I find that for marine boilers it is better to throw the fuel to the end of
the bars, by reversing the action of the fire bar as described in the specification of
my former patent, to cause the clinker to travel to the front of the fire where I
cause it to accumulate on or near the dead plate, or to be deposited on the flue
bottom, or into a receptacle in front of the furnace.
I also sometimes cast very large air spaces near the front end, so as to allow
pieces of clinker and ash to fall through, that the air may chill the clinker before
it is taken from the furnace by hand or by machine.
This plan can be adopted also with fan machines. In some cases I use a bridge
which overhangs the bars at the back end, and cause the fuel to move from the
back to front as described in the next paragraph, such bridge being constructed so
as to admit air to the bar ends to keep them cool, which air being heated from the
bars passes into the furnace behind the bridge. In theso cases, I generally use a
dead plate or iron door suspended from such bridge or moving freely in it, to keep
the fuel from getting underneath the bridge.
I modify my bars when I use them, to bring the coal from the bridge end to the
front, by doing away with the back dead plate, and placing a bridge constructed of
cast iron faced toward the fire with fire brick, this bridge I make of castings made
so as to allow thin streams of air to pass, thus keeping the bridge cool with the
smallest possible amount of air, which is caused to pass between the iron plates for
a considerable distance as set forth in Fig. 6. I inay use an ordinary beater to
distribute the fuel in combination with my new feed motion, but I prefer for
general use the shovel and spring. I sometimes place the cam which actuates the

page_text: spring, and also the cam which actuates the feeding apparatus, on the bar shaft,
and so do away with any shaft in front of the boiler except the one.
Sixthly. I make the front of the feeding box nearly open so that by removing
the plate which is placed as a cover thereon, the pusher can be removed and the
whole arrangement be open-a valuable point in case any piece of iron or other
material gots in too large to go through, and too hard to crush.
Seventhly In the box I place a plate which rests on the shaft that drives the
machine, on which shaft I have one or more projections that lift this plate and let it
drop again—thus disturbing the fuel in the hopper-a rod being attached to the
plate that projects upward into the fuel like a T preventing the commonly known
tendency to arch in fuel so fed.
Having now described my invention and the best mode known to me of carrying
it into effect, I wish it to be understood that while I believe all the improvements
or variations on my former patents herein described to be new, I do not claim
them as separate and independent inventions, but only in combination with
other necessary parts of my invention hereinafter mentioned, so as to form a
complete machine, substantially as described but I do claim as independently new
the following.
1/ The improvement on my patent of 1875, in which an apparatus for disturbing
the fuel in the hopper, an independent pusher and a shovel, are all worked in
combination substantially as described
2nd The combined arrangement of pushing and shovelling mechanism, both
driven by the same shaft substantially as described.
3rd/The combination of the spring lever and shovel arm, constructed substantially
as described, with two rolling segments of circles of different diameters working
on each other, so as to act with a rolling motion instead of striking a buffer
as is usually done.
4th The method of and apparatus for regulating the feed of fuel substantially as
sot forth in part first of the specification and drawings relating thereto.
5th The manufacture and use of fire bars having their upper surface arranged
substantially as described and set forth in Fig. 6, also the combination of the
bridge shaped bar with the steam jet or jets substantially as and for the
purposes described, also the bridge constructed substantially as set forth
and shown in Fig. 6.
In witness whereof I the said Edward Bennis have hereunto set my hand
and seal this nineteenth day of June in the year of our Lord one thousand
eight hundred and eighty three.