IMPROVEMENTS IN FURNACES AND FIRE-BARS FOR STEAM BOILER AND OTHER FURNACES
Year: 1876

page_text: LETTERS PATENT to Francis Erskine, of the City of Manchester, in the County
of Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN FURNACES
AND FIRE-BARS FOR STEAM BOILER AND OTHER FURNACES."
Sealed the 28th March 1877, and dated the 7th October 1876.
PROVISIONAL SPECIFICATION left by the said Francis Erskine at the Office
of the Commissioners of Patents on the 7th October 1876.
FRANCIS ERSKINE, of the City of Manchester, in the County of Lancaster,
Engineer. "IMPROVEMENTS IN FURNACES AND FIRE-BARS FOR STEAM BOILER AND
OTHER FURNACES."
The object of my Invention is such an arrangement and combination of furnace
and construction of fire-bars as will cause the fuel to be gradually fed forward from
the feeding end of the furnace towards the fire-bridge and will cause the fresh fuel
to be fed under the incandescent fuel, so that the gases generated therefrom will be
consumed and smoke will thus be prevented.
My Invention consists in forming the fire-grate of a series of bars shaped some-
what like the letter U in cross section, and placed side by side in the lengthway of
the furnace with the open side upwards, spaces being left between the bars for air,
and slits for air being formed in the sides of the fire-bars to adinit air to the fuel above
the open side of the tire-bar. In the round part of each U bar a screw the length
of the bar is placed, and these screws are geared together by toothed wheels at the
firing end to be rotated slowly, the action of the screws forcing the fuel forward,
and under the incandescent fuel on to the bars, the fuel being also at the same time
forced upwards by partitions across the U bar placed at suitable intervals. The
ashes from the bars (such as do not pass througn the air spaces) fall into the flue
in a space left at the inner ends of the fire-bars, and such ashes are removed when
required through a door in a partition, passing across the flue which supports the
inner ends of the fire-bars. The fuel may be supplied to the fire-bars by an hopper
at their front ends, if desired.
Instead of a screw in each U bar there may be a wedge-shaped bar with ratchet
or saw-like teeth upon its upper edge, these bars having a to-and-fro end motion
imparted to them to push forward the fuel. These slide bars may also be made as
above described, with teeth on their upper edge, and each bar with two or more

page_text: inclines on its lower edge to rest upon cross bars or rollers in the hollow of the
fire-bars, so that the reciprocating bars will lift when pushed forwards and descend
when drawn backwards.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Francis Erskine in the Great Seal Patent Office on the 2nd April 1877.
FRANCIS ERSKINE, of the City of Manchester, in the County of Lancaster,
Engineer. "IMPROVEMENTS IN FURNACES AND FIRE-BARS FOR STEAM BOILERS AND
OTHER FURNACES."
The object of my Invention is such an arrangement and combination of furnace
and construction of of fire-bars as will cause the fuel to be gradually fed forward from
the feeding end of the furnace towards the fire-bridge, and will cause the fresh fuel
to be fed under the incandescent or burning fuel, so that the gases generated there-
from will be consumed and smoke will thus be prevented.
My Invention consists in forming the fire-grate of a series of bars shaped some-
what like the letter U in cross section, und placed side by side in the lengthway
of the furnace with the open side upwards, spaces being left between the bars
for air and a slit or slits for air being formed in the sides of the fire-bars to
admit air to the fuel above the open side of the fire-bar. In the round part of
each bar a screw the length of the bar is placed, and these screws are geared
together by toothed wheels or by a shaft and worms and worm wheels at the firing
end, so as to be rotated slowly by continuous rotary or intermittent motion from
any suitable motive power, the action of the screws forcing the fuel forward and
under the incandescent or burning fuel on the bars, the fuel being also at the same
time forced upwards by the action of the screws and partitions across the U bar,
placed at suitable intervals and forming bearings for the screw. The ashes from the
bars (such as do not pass through the air spaces) fall into the flue at the inner ends
of the fire-bars, and such ashes are removed when required through a temporary
door in a frame, passing across the flue which supports the inner ends of the fire-
bars. The fuel is supplied to the fire-bars by a hopper at their front ends, which
also forms the door to the furnace.
Another mode of carrying out the object of my Invention consists in using one
or more wedge-shaped bars with ratchet or saw-like teeth upon their upper edges,
these bars having a to-and-fro end motion imparted to them to push forward the
fuel. These slide bars, with teeth on their upper edge, as above described, are also
made by preference with two or more inclines on their lower edges to rest upon
cross bars or upon rollers on surfaces connected with the side bars, so that the
reciprocating bars will lift when pushed forwards and descend when drawn back-
wards. These reciprocating bars and their side bars within which they slide are
also combined with hollow air fire-bars, or with short cross fire-bars by preference.
Fig. 1 is a longitudinal section; Fig. 2, a cross section; Fig. 3, a plan section
above the fire-bars; Fig. 4, an end view; and Fig. 5, a plan view, illustrating one
mode of carrying out my Invention.
My Invention is applicable to furnaces for various purposes, but is illustrated as
applied to the furnace of an internal flued boiler. a, the flue of the boiler in which
the furnace is formed; b, the bars of U form in cross section, which pass lengthway
of the furnace and rest upon a cross bar or bars C, and are secured to a hollow cross
bearer d (as shown) at the back end of the furnace. These bars bare shown level,
but they may be inclined downwards from the front to the back. Between the U
bars I prefer to place hollow fire-bars e, which have lugs e¹ at each side at intervals
to rest upon the edges of the U bars. These bars e may be formed with grooves or
ribs on the tube, that is, by cross bars connected by or formed upon the tube. The
air to the fire passes up through the space or spaces formed between the upper

page_text: edges of the U bars and the sides of the tubular fire-bars e, which communicate
with the hollow cross bearer d at the back of the furnace, to which air is admitted
to pass along through the hollow bars to the front end of the furnace, such air
being heated in its passage through the hollow bearer and bar and escaping from
each bar through a grid e in the upper face of the bar. Immediately under this
grid in each bar there is an opening (closed by a sliding door) to allow any ash or
dirt that may enter through' the grid to drop out at intervals. The screw b¹ in
each Ubar rests in bearings 62 in the bar, that portion of the screw thread which
comes opposite each bearing being cut away for the bearing which forms a partition
in the bar tending to direct the fuel upwards. The screw thread diminishes in
diameter in steps, as shown, the larger diameter being at the feeding end. The
screws may be driven by a shaft 63, having a worm for each screw in gear with a
worn wheel on the end of the screw, as shown, or by other suitable gearing.
The fuel is fed to the screws by a hopper f forming a door which can turn on a
hinge. The hopper (f) is made with divisions (f) in it which are the width
of the space between the U bars, and a horizontal slide f³ is placed in the hopper,
which slide has a hole or holes in it as required, so that when the slide f3 is in one
position the fuel can fall from the hopper to the screws below, but when the slide is
in another position the holes in it are under the partitions få in the hopper, and its
passages to the screws are closed; this slide fa is worked by an arm on a shaft f*
having its bearing on the end of the hopper, the front end of the shaft having a
lever handle f on it for actuating the slide (f³). This slide has a vertical pro-
jection f upon that part which remains outside the hopper, which projection comes
inside a hook projection g from the framing h carrying the hopper when the slide ƒ³
is in one position, and is withdrawn when the slide is in the other position, so that
when the slide is pushed into the hopper the fuel in it is retained, and the door
which forms part of the hopper is released and it can be turned on its hinge, and
when the door is shut and the slide f³ is withdrawn the door is secured, and at the
same time the fuel is free to pass to the screws.
The hopper may be made to slide on one side or lift vertically, a weight being
used in the latter case to help to balance the weight of the hopper and its contents.
The ashes or cinders which do not pass through the air spaces of the fire-bars will
pass over the hollow cross bearer d and into the flue beyond, and while they are
accumulating sufficiently to fill up the space between the ash-pit and flue there is a
temporary door used. These cinders and ashes as they accumulate are removed at
intervals, sufficient being left to keep the space between the ash-pit and flue closed.
Fig. 6 is a vertical longitudinal section; Fig. 7, a cross section; Fig. 8, a plan
section above the fire-bars, and Fig. 9, a front elevation showing another method of
carrying out the object of my Invention. By this method two bars may be placed
parallel to each other connected by cross pieces, and between these bars there is a
bar with teeth on its upper edge having a reciprocating motion imparted to it in
the direction of its length and a lifting motion at the same time, and a series of
these combined reciprocating and side bars may be placed side by side with air
spaces provided. Or a series of this combination of side bars and reciprocating bars
may be used combined with fire-bars between them, as illustrated by Figs. 7 to 9
inclusive. a, flue; bare the side bars between which the reciprocating bars slide
connected at the back end, as shown in Fig. 7, and by parts at the under side
which carry the rollers for the toothed reciprocating bars C, which rest upon the
said rollers that come into the toothed reciprocating bars which are channeled
underneath, as shown. There is an incline formed both on the reciprocating bar C,
and the part 6 upon which the roller C₁ works, and there are parts C² in the channel
of the reciprocating bar which allow the rollers to roll to the required extent but
no further. The parts b' upon which the roller C¹ rest are disconnected from the
ide bars b except at the two ends, so that dirt or ashes getting between the
eciprocating bar C, and the side bars 6 will not come upon such parts, but will drop
lear of them into the ash-pit. The front end of the reciprocating bars C pass
hrough holes in the front supporting cross bar k, and the ends at the upper side

page_text: are inlined, as shown, to keep the hole sufficiently filled in every position of the
reciprocating bar C, so that the fuel cannot escape through such hole.
The back end of the reciprocating bar C is formed, as shown in Fig. 7, to force
the fuel up the incline formed between the two side bars b, as shown, the end of
which rests on a cross bearer d which may be protected by a fire-brick block d'
(as shown). The spaces between the side bars 6 for the reciprocating bar C is filled
up by cross bars e, as shown, which are cast connected to a central boss passing
across the bars; a few only of these cross bars are shown in Figs. 6 and 8. The
reciprocating bars C are actuated by a crank on a crank shaft and connecting
rods m, as shown, or in place of cranks excentrics may be used. Where there are a
number of reciprocating bars I prefer to give alternate reciprocation to them, that
is, work them so that each alternate bar is making its forward stroke while the other
alternate bars are making their backward strokes. The spaces between the sides b
for the reciprocating bars are closed at the front end of the furnace by plates e¹.
The fuel is fed by a hopper also forming a door arranged as above described in
reference to Figs. 1, 4, and 5, and the ashes and cinders are allowed to accumulate
between the ash-pit and flue, and are removed as herein-before described in reference
to the arrangement shown by the Figs. on Sheet 1.
I have now particularly described the nature of my Invention and the mode of
carrying the same into effect, and wish it to be understood that I am aware that
screws have been proposed in troughs for feeding fuel under the burning fuel, and
I make no claim to such screws or troughs as so proposed to be used; I am also
aware that reciprocating fire-bars have been used for passing the fuel upon them
towards the back end of the furnace, and I make no claim to such reciprocating
fire-bars as so used, but what I do claim as my Invention is,-
Firstly. An arrangement and combination of furnace formed by a series of U fire-
bars with screws in them placed side by side, or such bars with hollow fire-bars for
air between them as herein-before described and illustrated by the accompanying
Drawings on Sheet One.
Secondly. The combination of a door and hopper arranged on hinges or in slides,
substantially as described when used in combination with screws and bars or
troughs for feeding fuel.
Thirdly. The combination of toothed reciprocating bars (c) between side bars (b)
arranged to feed fuel under the burning fuel, substantially as herein-before described
and illustrated by the Drawings on Sheet Two.
Fourthly. The supporting of such reciprocating bars (c) on rollers (c), and the
giving of vertical movement to the bars by inclines, substantially as herein-before
described and illustrated by the Drawings on Sheet Two.
Fifthly. The combination of toothed reciprocating bars for feeding the fuel under
the burning fuel with fire-bars filling the space between the side bars (b), sub-
stantially as herein-before described and illustrated by the accompanying Drawings
on Sheet Two.
Sixthly. The combination of a door and hopper arranged on hinges or in slides
substantially as described when used with reciprocating bars for feeding fuel.
In witness whereof, I, the said Francis Erskine, have hereunto set my hand
and seal, this Thirty-first day of March in the year of our Lord One thousand
ight hundred and seventy-seven
FRANCIS ERSKINE. (L.S.)