IMPROVEMENTS IN FURNACES AND STOVES DESIGNED ESPECIALLY FOR BURNING BITUMINOUS FUELS
Year: 1883

page_text: LETTERS PATENT to John Clayton Mewburn of 169 Fleet Street in the City
of London Patent Agent and Consulting Engineer for an Invention of
"IMPROVEMENTS IN FURNACES AND STOVES DESIGNED ESPECIALLY FOR
BURNING BITUMINOUS FUELS "
Communicated to him from abroad by Luther
Calvin Voorhees of New York, United States of America, Manufacturer
PROVISIONAL SPECIFICATION left by the said John Clayton Mewburn at
the Office of the Commissioners of Patents on the 17th February 1883.
"
DESIGNED ESPECIALLY FOR BURNING BITUMINOUS FUELS
JOHN CLAYTON MEWBURN of 169 Fleet Street in the City of London, Patent
Agent and Consulting Engineer "IMPROVEMENTS IN FURNACES AND STOVES,
him from abroad by Luther Calvin Voorhees of New York, United States of
[Communicated to
America, Manufacturer]
The object of this invention is to provide for more economical and convenient
burning of bituminous coal and other similar fuels, in boiler furnaces and cooking
stoves or ranges, than by the appliances heretofore in use.
The stove and furnace contemplated by this invention are each constructed with
a double fire chamber, or with two parallel fire chambers, separated by a hollow
partition wall, the hollow of which forms an air-flue through which cold air flows,
being heated therein, and escaping therefrom in jets into the fire chambers where
it mingles with the burning gases. There are also other air-heating flues traversing
the hollow outer walls and terminating in perforations through which jets of
heated air pass into the fire chambers at successive points. By thus injecting heated
air the smoke and unconsumed gases are ignited-and-their-combustion effected-in-a-
far more efficient manner than when cold air is used.
I will first describe the improved boiler furnace which forms the first part of this-
nvention.
The boiler or steam generator is preferably provided with two longitudinal flues,
rranged side by side, and it is set in masonry in much the ordinary way. Two
ire chambers are built in the masonry beneath the boiler and are separated from
ach other by a partition wall extending longitudinally directly beneath the centre
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page_text: of the boiler. In the front of each fire chamber is a grate or fire bed, and just back
of this is a bridge wall or deflector-Beneath each grate is an ash pit and in the
front wall of each pit is an ash door. In the front wall of each fire chamber is a
feeding door and beneath this door is a poke-hole, just over the grate. These parts
may all be of the usual construction.
At the rear ends of the two fire chambers a draft aperture is formed through
the partition wall, affording communication between the two chambers. The rear
portion of each chamber has an imperforate floor or hearth.
The two boiler flues open into a breeching or smoke box at the front. This is
divided into three compartments from the middle one of which the uptake springs,
while each of the side compartments communicates with one of the flues at the
rear and with one of the fire chambers below.
In each side compartment is a valve which when turned up closes the opening
from the side to the middle compartment, and when turned down closes the opening
from the side compartment to the fire chamber below. At the rear of the boiler is
a trunk or smoke box which is undivided and into which both flues open. Both
fire chambers communicate with this trunk through openings which may be closed
by valves.
I will now describe the means for securing a supply of heated air to unite with
the gases of combustion after they have been liberated from the fuel, in order that
they may be completely consumed.
In each side wall of the furnace is formed an air flue which extends from the
front to the rear, downward, and thence forward to the front position of the fire
chamber where it terminates in a perforated plate or tile. Another air flue leads
from any convenient point outside the furnace, passes into the partition wall and
extends through the latter to the front of the fire chambers with both of which it
communicates through perforated tiles. It is divided into two branches at its
front portion by a plate set between the two tiles. Thus each fire chamber is
provided with two perforated tiles in its front portion above the grate set opposite
each other in its side walls; and through these perforations jets of highly heated
air enter the chamber the air being heated by passing through the flues traversing
the hot walls of the furnace.
Another flue leads from outside the furnace to the partition wall, and extends
through the latter to the rear, where it terminates in an air-chamber arranged
directly over the draft-aperture. This chamber is formed of perforated tiles at
its sides and bottom, the bottom tile forming the roof of the aperture, so that the
heated air passes from this chamber in jets into both fire-chambers and into the
apertures. A door opens into this air-chamber through the rear-wall of the
furnace.
The
The operation is as follows:-Before kindling the fire both valves in the
breeching are turned down and both valves in the trunk are turned up or opened.
The fire is lighted in both chambers, and the action in both is then the same.
products of combustion from both grates pass backward, ascend into the trunk
and pass forward through the boiler flues into the breeching where both streains
unite as they enter the middle compartment and pass up through the uptake flue.
When either or both the fires are fully kindled, the engineer observes in which
the coal is most thoroughly coked and incandescent. He then turns up the valve
in the breeching immediately over that chamber (which I will assume is the
left hand chamber) and turns down (or closes) both valves in the trunk. The
products of combustion from the fuel in the right-hand chamber then flow rear-
wardly therethrough, pass through the draft aperture in the partition wall into
the left hand chamber, How forward there through and over the bed of incandescent
fuel therein and then, with the gases from that fuel, ascend into the left hand
compartment of the breeching, flow rearwardly through the left hand boiler flue,
enter the trunk, flow thence forward through the right hand flue into the right
hand compartment of the breeching and thence into the middle compartment
thereof, and up the uptake.
4

page_text: The fresh or uncoked fuel in the right hand fire chamber evolves more or less
volatile hydrocarbon gases or smoke. With this is mingled a portion of heated air'
from the perforated tiles, and the mixture of burning gases flows rearwardly
and in passing through the draft aperture receives a fresh accession of heated air
through the tiles forming the air-chamber. This aperture is of contracted area, so
that the air and gases are forced to commingle, and a further combustion ensues
during their forward flow through the left hand chamber. When the gases reach
the bed of incandescent fuel only the more refractory constituents are unconsumed
and these are ignited by the heat from this fuel and combine with the third supply
of heated air admitted through the tiles in the front of this chamber.
combustion is completed in the boiler flues.
The
After the fuel in the right hand fire chamber is fully coked and ceases to give
off sooty matter, fresh fuel may then (or as soon as required) be fed to the left
hand chamber, whereupon the attendant will reverse the valves in the breeching,
turning the right hand one up and the left band one down, which will cause a
reverse of the current of gases through the fire chambers and flues. Thus the
operation proceeds, the two fires being fed alternately, and the valves in the
breeching each time shifted, so that the smoke evolved from the fresh fuel will be
drawn over the bed of incandescent coals.
By a suitable arrangement of the draft devices a boiler with a single flue may
be used; or a multitubular boiler may be substituted.
I will now describe the improved cooking stove which forms the second part of
this invention. This stove in several respects resembles my furnace, but as a
cooking stove is usually operated by persons who are ignorant of the principles of
combustion and of the best methods of managing fuel the inventor of this stove has
endeavored to render it so simple in its operation that any person of fair intelligence
can use it with but little trouble.
The outer shell or casing of the stove is built up of iron plates as usual. The
oven, grate, ash-pit, flues around the oven, and pot-boles on the stove and pot-hole
covers, are all of the usual construction except as hereinafter described. There are
preferably six pot-holes, three at the front and three at the rear. Beneath the two
right hand pot holes is the grate which is set higher than usual so that the fuel
chamber over it is somewhat shallow. Fuel is fed in through a door in front and
raked through a poke-hole beneath this door. From the fuel-chamber two parallel
gas combustion chambers or flues extend to the left over the oven and beneath the
pot-holes. These chambers are separated by a hollow partition which extends from
the left hand end of. the stove to the fuel-chamber where it terminates in a
perforated plate. The hollow of this partition forms an air heating flue, into
which air flows through an aperture in the left hand end of the stove, and escapes
in part through the perforated plate into the fuel-chamber.
From both combustion chambers a single flue extends down the left hand end
of the stove, at the left of the oven, thence to the right beneath the oven, thence
rearwardly and to the left, and thence up the left hand end of the stove where it
communicates through an aperture with a trunk or smoke box at the rear of the
stove. On the top of this trunk is the thimble to which the stove pipe is fitted,
leading to the chimney. In ordinary use the products of combustion pass through
this flue around the oven, but when kindling the fire a valve is opened which
affords them more direct passage to the trunk. The particular arrangement of
these draft flues is immaterial, as any good and customary system of flues and
valves or dampers will answer.
On the bottom of each gas combustion chamber are placed two baffle-bricks, one
directly beneath each pot hole, to deflect the flames upwardly against the holes.
Between each two holes an air-bridge is arranged against the stove-top, there
being five of these bridges, two in each gas combustion chamber, and one crossing
the fuel chamber and forming a continuation of the hollow partition. Each air
bridge consists of a trough shaped plate with open ends and perforated bottom.
The stove top is constructed with long and short cross plates as usual, and the

page_text: bridges are fastened to these cross-plates and may be removed with them. The
interior of each bridge communicates with some air heating flue which traverses
the hot walls of the stove. There are four of these flues one of which is the hollow
in the partition wall already referred to, and the others are in the outer walls of
the stove. The two air bridges crossing the right hand ends of the two gas-
combustion chambers communicate with the right hand end of the hollow partition,
so that the greater portion of the air heated therein flows to front and rear through
these bridges (which thus constitute branch flues) and escapes through the per-
forations therein into the two combustion chambers.
The remaining three air-heating flues are formed by leaving air spaces between
the fire bricks or tiles which line the sides of the fuel and combustion chambers
and the outer shell of the stove. The outer shell is cast with flanges or projections
which hold the tiles out of contact with it, and the intervening space is utilized to
form flues, the tiles being held back against these projections by flanged plates
between every two tiles, the flanges of which confine the ends of the tiles, and
which are fastened to the shell.
One flue extends along the front wall of the stove, from an aperture in the shell
near the feeding door to the left hand air bridge over the front gas-combustion
chamber. Another flue extends along the rear wall from an aperture in the shell
to the left-hand air bridge over the rear gas-combustion chamber. And the
remaining flue extends along the rear and right-hand walls from an aperture in
the shell at the rear to the air bridge which crosses the fuel chamber, thereby
supplying heated air in jets to combine with the gases liberated from the fuel
therein. Air also enters this chamber from said flue through perforations in the
flanged plate between the two tiles at the right hand side.
The air bridges in the gas combustion chambers depend about one third of the
depth of the chambers, and are arranged alternately with the baffle bricks, which.
_project up about one third the height of the chambers. The effect of this alternate
arrangement is to compel the flames to take a sinuous course thereby impinging
against both the pot-holes and the roof of the oven and to cause them to
thoroughly mingle with the successive portions of heated-air admitted through
the air bridges.
In each gas-combustion chamber a fire brick is arranged to the right of the
right hand baffle brick, and so close to it as to leave only a narrow space or slot
between. A flue or air-space leads from the ash-pit to this slot, so that heated air
may enter the chamber through the alot. This fire brick is just below the right
hand air bridge and the two form a slight contraction or throat at the entrance
to each gas-combustion chamber, the effect of which is to retard the smoke for an
instant in the fuel chamber, where it is subjected to the heat from the bed of coals,
and to force it to combine on entering the gas-combustion chambers, with the
heated air admitted above and below.
The construction of my stove renders it as effective and economical as those
stoves having two fuel chambers into the first of which the fresh fuel is fed, and
into the second of which the fuel is pushed when it has become incandescent, and
its operation is much simpler than that of stoves of that character. The fuel has
only to be fed in in suitable quantities and whenever necessary and to be raked
or poked at intervals, its manipulation being as simple as when burning wood
or coke.
A heating stove may be made on the principle of my cooking stove, by omitting
the oven and substituting radiating flues for the oven flues. Or a boiler or other
furnace may be built on the same principle-A cooking stove might also be made
on the principle of my boiler furnace, but its operation would require more care
and skill than that of the cooking stove I have described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Clayton Mewburn in the Great Seal Patent Office on the
25th July 1883.
JOHN CLAYTON MEWBURN of 169 Fleet Street in the City of London Patent
Agent and Consulting Engineer "IMPROVEMENTS IN FURNACES AND STOVES
DESIGNED ESPECIALLY FOR BURNING BITUMINOUS FUELS" (A communication to
me from abroad by Luther Calvin Voorhees of New York, United States of
America Manufacturer)
The object of this invention is to provide for more economical and convenient
burning of bituminous coal, and other similar fuels, in boiler furnaces and cooking
etoves or ranges, than by the appliances heretofore in use.
The stove and furnace contemplated by this invention are each constructed with
a double fire-chamber, or with two parallel fire-chambers, separated by a hollow
partition wall, the hollow of which forms an air-flue through which cold air flows,
being heated therein, and escaping therefrom in jets into the fire-chambers, where
it mingles with the burning gases. There are also other air-heating flues traversing
the hollow outer walls, and terminating in perforations through which jets of
heated air pass into the fire-chambers at successive points. By thus injecting
heated air the smoke and unconsumed gases are ignited and their combustion
effected in a far more efficient manner than when cold air is used.
I will first describe the improved boiler furnace which forms the first part of
this invention, the same being shown in Figures 1 to 5 of the accompanying
drawings. Figure 1 is a front elevation of my furnace, partly in section; Fig. 2
is a vertical longitudinal section; Fig. 3 is a vertical transverse section; and Figs.
and 5 are horizontal sections. Each of these views is in section cut along the like
numbered lines (1-1, 2-2, &c.,) in the remaining figures. The light open section-
shading denotes masonry, the dark close shading denotes metal; the feathered
arrows indicate the course of the draft, and the small featherless darts indicate the
course of air currents.
A designates the boiler or steam generator, which is set in masonry in much the
ordinary way. B B are two fire-chambers built in the masonry beneath the boiler,
and separated from each other by a central longitudinal wall or partition C. In
the front of ench chamber B is a grate or fire-bed a, under which is an ash-pit c.
Back of the grate is a bridge-wall or deflector b, and behind this the floor of the
chamber forms an imperforate hearth b. Each chamber B has a feeding door d,
and beneath this, and on a plane with the grate surface, is a poke-hole e. (Fig. 1.).
An ash door f beneath, opens into the ash-pit c. These parts may all be of the
usual construction.
At the rear end of the chambers B B, a communicating aperture D is formed
through the wall C, as shown in Fig. 2. The boiler A is formed with two flues
E E, arranged side by side, as usual. These flues open into a breeching (or smoke-
box) F at the front of the boiler, and into a trunk (or smoke-box) G at the rear.
The breeching F is divided into three compartments, from the centre of which the
uptake flue H springs, and leads to the chimney. Each of the side compartments...
communicates always with one of the flues E; and contains a valve i, which when
turned up, affords communication with the chamber B below, and when turned
down affords communication with the central compartment. The valves i i have
handles extending through the front wall, by which they may be turned.
The trunk G at the back is undivided, and contains two valves, which when
turned down, close openings kk into the chambers B B below. The handles m m
of these valves project through the rear wall.
-x)

page_text: I will now describe the means for securing a supply of heated air to unite with
the gases after they have been liberated from the coal, in order to perfect their
combustion.
In each side-wall of the furnace is formed an air-flue I, which leads from the
front, where it may be provided with a door (Fig. 1) and extends thence back to
the rear, thence downward, (Figs. 3 and 4) and thence forward, (Fig. 5) where it
terminates in a perforated plate, or tile of fire-brick, n, in the front of the
chamber B, just above the grate.
Another air flue J leads from any convenient point outside the furnace, passes
into the partition C, and extends through it to the front of the chambers B B,
with which it communicates through perforations in tiles pp, arranged the same
as the tiles n n, but on the opposite sides of the chambers. A plate o divides the
flue J at its front.
Another air-flue K leads from any convenient point outside the furnace, enters the
partition C, and extends through the same to the rear thereof, where it terminates
in an air-chamber M just over the aperture D. This chamber is formed of per-
forated tiles q q at its sides, and a tile q¹ on its bottom. A door L, lined with
fire-brick, opens into this chamber, through which to remove ashes or dust, and
another similar door N opens below, through which to rake ashes from the
hearths bb.
The
I will now describe the operation of the furnace-Before kindling the fire, tho
valves are turned up, and both the valves ii are turned down. The kindlings
and coals are placed upon the grates a a, the fire lighted, the doors d d closed and
the doors ff left open. The action in both chambers is then the same.
products of combustion pass from the grates backward through the chambers B B,
up through the openings k k into the trunk G, forward through the fines E E, into
the breeching F, through the openings g g therein, and up the flue H in which the
two streams unite-When one or both of the fires are fully kindled, the engineer
observes in which chamber the fuel is most thoroughly coked and incandescent.
He then turns up the valve i immediately over that chamber, and turns down both
of the rear valves. The drawings show the parts in these positions, the fuel in
the chamber B at the left-hand (in Fig. 1) being assumed to be burning the
brightest. The products of combustion from the right-hand chamber B now pass
back through that chamber, flow through the opening D in the dividing wall, and
so enter the back of the left-hand chamber B, flow forward through that chamber
and mingle with the gases from the burning fuel on the grate in the front thereof,
and the combined gases ascend, through the opening h into the breeching F, pass
back through the left-hand flue E into the trunk G, thence forward through the
right-hand flue E into the breeching F, thence through the opening g therein and
up the flue H.
The fire heats the walls of the furnace intensely hot, and as the draft causes air
to flow in through the air-flues I, I, J, and K, this air is highly heated by contact
with the hot walls, and as it enters the fuel chambers through the perforations in
the tiles n n, p p, q q and q', it mingles in sufficient quantities with the burning
and unconsumed gases, and is so hot that it does not perceptibly cool the fire.
The fresh or uncoked fuel in the right-hand chamber B evolves first its more
volatile constituents in the form of smoke-With this is mingled a portion of
heated air from the tiles np in this chamber, and the mixture of burning gases
and unconsumed particles of carbon flows back through this chamber, over the
hearth 6, and in passing through the opening D receives a fresh accession of highly
heated air through the tiles qq q'. This opening D is of contracted area, so that
the air and gases are forced to commingle, and a further combustion ensues during
their forward flow through the left-hand chamber B. By this time the more
easily combustible constituents will have been consumed, the more refractory gases
and particles are remaining unconsumed, and these are caused to ignite by passing
over the incandescent mass of coked and highly heated fuel on the grate in the

page_text: left-hand chamber--At this point a fresh supply of air enters through the
tiles n and p and mingles with the burning gases to complete, their combustion.
After the fuel in the right-hand chamber B is fully coked and ceases to give off
sooty matter, fresh fuel may then, or as soon as required, be supplied to the
left-hand chamber, whereupon the attendant will reverse the valves i i, turning the
right-hand one up and the left-hand one down, which will cause a reversal of the
current of gases through the fire-chamber and flues. Thus the operation proceeds,
the two fires being fed alternately, and the valves each time shifted so that the
smoke evolved from the fresh fuel will be drawn over the bed of incandescent coal.
The pre-heating of the second supply of air is a valuable and important feature
in this furnace. With cold air it would be impossible to effectually consume all
the smoke evolved from the bituminous coal, as cold air would reduce the
temperature of the hydro-carbon gases to such an extent that a complete ignition
of the carbon and the complete conversion of all the carbonic oxide could not
result.
It is preferable to use a boiler A having two flues, as shown, but a single flue
may be used instead, by having the draft flue H lead from the trunk G. Or, a
tubular boiler may be used, if desired.
I am aware that a double furnace is not in itself new, as such furnaces have
been made with the aperture through the dividing wall at its front, affording
communication between the two grates. This construction permits the coal to
shift from one chamber to the other, and the two fires cannot be kept distinct.
I am also aware that it is not new to pass the smoke from one fire chamber over
the incandescent coals in the other, that having been done by carrying the smoke
from the first chamber forward through a flue beneath the furnace, and then
passing it backward through the second chamber; which is precisely the reverse of
the method adopted in my improved furnace. The success of this furnace is
largely due to placing the aperture D at the back, so that the smoke from the
fresh fuel is drawn first backward to it, and then forward through the second
chamber before it reaches the incandescent coal; and also to the effective means
provided for supplying heated air plentifully to the burning gases at successive
points, before these gases reach the incandescent coals.
I will now describe the improved cooking stove which forms the second part of
this invention. This stove in several respects resembles my furnace, but, as a
cooking stove is usually operated by persons who are ignorant of the principles of
combustion and of the best methods of managing fuel, the inventor of this stove
has endeavored to render it so simple in its operation that any person of fair
intelligence can use it with but little trouble. This stove is shown in Figs. 6 to 13
of the drawings.
Fig. 6 is a front elevation of the stove; Fig. 7 is a vertical longitudinal section,
cut along the line 7-7 in Fig. 9; Fig. 8 is a fragmentary section cut in the same
plane as Fig. 7 but looking from the rear toward the front; Fig. 9 is a horizontal
section, the lower half of which is cut along the line 98-9, and the upper half
along the line 9b-9b in Fig. 7; Fig. 10 is a transverse section cut along tho
lines 10-10 in Figs. 7 and 9; Fig. 11 is a plan of the stove on a reduced scale;
Fig. 12 is an enlarged fragmentary view; and Fig. 13 is an enlarged fragmentary
section cut along the line 13-13 in Fig. 9. All the views except Figs.
11, 12 and 13, are drawn to the scale marked on Fig. 6, but this scale is not
essential, as the stove may be made of any size.
'
The outer shell or casing of the stove, which is built up of iron plates as usual,
is lettered A. B is the oven, C the ash-pit, and D the grate or fuel-bed. The
grate D is set higher than usual, making the fuel chamber E above it quite shallow...
From the chamber E two parallel combustion chambers or passages F F extend to
the left-hand and of the stove. These are separated by a partition-wall G, which
is hollow, being made of two plates a a (Figs. 9 and 10). The right-hand end of
this partition is closed by a perforated plate b. The hollow in the partition G

page_text: forms an air-flue H, into which air flows through an aperture c in the left-hand
end of the shell A.
་
A plate h, (Figs. 7, 10 and 13,) forms the bottom of the flue H, the floors of the
chambers F F, and the roof of the oven B. At the left-hand end of the stove a
flue I is formed, which descends between the side of the oven and the end-wall A,
and then extends to the right-hand beneath the oven. This flue is divided by a
central plate k for some distance, and valve or damper K (Figs. 7, 9 and 10)
worked by a rod K¹, extends from the top of the plate k to the rear wall A of the
stove. In kindling the fire this damper is opened, as shown in Fig. 10, and the
products of combustion pass directly through it and into a trunk J at the back,
from which they pass out through the stove-pipe, which is fitted onto the collar m
(Figs. 10 and 11.) But after the fire is well kindled, this valve K is closed, thus
compelling the gases to pass down through the flue I and under the oven, before
they reach the trunk J.
The stove is shown with six stove-holes d d, (Fig. 11). There are two long
cross-plates e and f, which are fastened in place, and three short cross-plates g g,
which are removable, and one. of which is shown removed in Fig. 12. The cross-
plate forms the top of the flue H. Four baffle-bricks ii are placed in the
chambers F F, two in each chamber, directly beneath the holes d d (Fig. 7).
Between every two holes dd, an air-bridge j is fixed to the cross-plate. One of
these is shown inverted in Fig. 12. Each air-bridge consists of a trough-shaped
iron plate with open ends and perforated bottom. (Fig 13.). The effect of these
obstructions ii and j j, arranged thus alternately above and below in each
chamber F, is to cause the burning gases in passing through them to take a sinuous
course, as indicated by the arrows in Fig. 7, deflecting them upward against the
stove-holes dd, and downward against the plate h, and retarding their exit, so
that they may give up as much of their heat as is practicable.
The two bridges which are fixed beneath the cross-plate e, communicate
(through apertures in the plates a a) with the air-flue H, and constitute flues H¹
branching therefrom. The air drawn into the flue H passes to its right-hand end,
and flows partly into the front and partly into the rear flue H', from which it
escapes through their perforations into the chambers F F. Some air also passes
through the perforations in the plate b.
The sides of the chambers F F and E are lined with tiles p p of fire-brick,
which are held in place by flanged metal plates M M, (Figs. 9 and 13) which are
screwed to the outer shell A. The tiles p p do not touch the shell A, the latter
being formed with projections or flanges 9 g, which hold them off and leave an
intervening air-space, which is utilized to form air-heating flues-At the front of
the stove a flue L leads from an aperture t, extends to the left, and communicates
with the interior of the left-hand air-bridge j, which thereby forms a branch-flue L'.
Another flue L is at the rear of the stove, and leads from an aperture t¹ to the
left-hand air-bridge j, whose interior forms another branch-flue L'.
At the rear of the stove there is another aperture u (separated from the
aperture by a flange v) and from it a flue N leads to the right-hand, and forward
to the interior of the air-bridge jover the chamber E, which thereby forms a branch-
flue N!.
In each chamber a tile n is arranged close to the right-hand brick i, so as to
leave a narrow slot o between the two. This slot is over an air-chamber or flue C¹,
and air passes up from the ash-pit C, through C¹, and o o, into the chambers F F.
The air which enters the chambers E F F through the perforated bridges j j is
all heated in the flues H, L L, and N, so that it keeps those flues and the bridges j j
from becoming too highly heated, and becomes itself so hot that it readily combines
with the smoke and burning gases. Thus the bridges jj keep the cross-plates e
and g g from becoming red-hot, and also brace or stiffen them, so that they are
less liable to break.
The tiles n n and the bridges ; ; above them serve to slightly contract the

page_text: entrance from the chamber E to the chambers F F, so that the smoke and gases.
are confined for an instant in the chamber E, where the heat is greatest, and are
mingled with the heated air entering through flue N' and plates M and b. As they
enter the chambers F F they receive heated air from the flues. H'H' above, and
slots oo below; and as they proceed they receive a further portion of air from the
flues L' L', and then pass down the flue I and around the oven. The gases are
thus highly heated and are mingled with successive jets of heated air, so that all
the smoke is consumed, and the combustion is rendered perfect. The coal is fed
in through the door E¹, and is raked or stirred when necessary by inserting a
straight poker through a hole w below this door.
The partition G forces the flames to pass in two parallel streams beneath all the
pot-holes, so that the front and rear holes will work equally well. This is the
case whether the valve K is open or closed.
This construction of my stove renders it as effective and economical: as those
stoves having two fuel-chambers, into the first of which the fresh fuel is fed, and
into the second of which the fuel is pushed when it has become incandescent, and
its operation is much simpler than that of stoves of that character-The fuel has
only to be fed in in suitable quantities and whenever necessary, and to be raked or
poked at intervals, its manipulation being as simple as when burning wood, coke
or anthracite coal.
Figs. 14 and 15 show the left-hand portion of a stove of somewhat modified
construction. Fig. 14 corresponds to Fig. 7, and Fig. 15 to Fig. 9-The
construction is the same as already described, except that the trunk J is omitted,
the collar m is set at the left-hand end of the stove, and there are two flues I I,
one leading from each chamber F, and both uniting under the oven, and ascending
between two plates k k as a flue I'. The chambers F F communicate through a
cross-opening P, and the valve K in the flue I¹ closes a direct-draft aperture which.
communicates with this opening. The flue H leads from the bottom of the stove,,
up through the flue I' and finally enters the partition G.
A heating stove may be made on the principle of my cooking stove, by omitting
the oven and substituting radiating flues for the oven flues. Or, a boiler or other
furnace may be built on the same principle.-A cooking stove might also be made
on the principle of my boiler-furnace, but its operation would require more care
and skill than that of the cooking stove I have described.
Having now described the nature of the said Invention as communicated to me
and in what manner the same is to be performed I declare that I claim :-
:
First A furnace (or stove) having two fire chambers, separated by a dividing
wall with a draft aperture through the said wall at one end thereof and a
grate in each chamber at the opposite end substantially as hereinbefore
described.
Second :—A furnace (or stove) having two fire chambers separated by a dividing
wall, a draft aperture through the said wall at one end thereof, a grate in each
chamber at its end remote from the said aperture, and air heating flues extending
through the hot walls of the furnace and terminating in perforations in the
opposite side walls of each chamber adjacent to the said grates substantially as
herein before described.
Third A furnace (or stove) having two fire chambers separated by a dividing
wall or draft aperture through the said wall at one end thereof, a grate in each
chamber at the end remote from the said aperture and an air heating flue
extending through the hot walls of the furnace and terminating in perforations
adjacent to the said aperture whereby the products of combustion in passing from
one chamber to the other through the said aperture are mingled with jets of heated--
air substantially as hereinbefore described.
Fourth: A boiler furnace having two fire chambers separated by a dividing wall
through which a draft aperture is formed at one end with a fuel grate in the
opposite end of each chamber and suitable valved openings above the said grates,
by means of which the products of combustion from either chamber can be caused
=
"F

page_text: to ascend immediately and to enter the boiler flue substantially as hereinbefore
described.
Fifth: The described arrangement of valves in the breeching F and trunk G
in connection with the two fire chambers B B, the boiler flues EE and the draft
flue H.
Sixth The air chamber M immediately over the aperture D formed of
perforated tiles and in connection with the hot air flue K as and for the purposes
set forth.
Seventh: A stove (or furnace) having a fuel chamber, a gas combustion
chamber or passage leading therefrom, alternate obstructions on opposite sides of
the said chamber or passage, which cause the gases to flow in a sinuous path, and
hot air inlets. adjacent to the said obstructions substantially as herein before
described and shown in Figures-6 to 15.
Eighth In a stove or furnace, the combination of a fuel chamber having a
grate, and two parallel gas combustion chambers leading therefrom, separated by a
partition wall and both communicating with the same draft flue, substantially as
herein before described and shown in Figures 6 to 15.
Ninth: A stove (or furnace) consisting of a fuel chamber, two gas combustion
chambers leading therefrom, a partition separating the said chambers, an air
heating flue extending through the said partition, and air inlet perforations through
which air from the said fiue may enter the combustion chamber substantially as
herein before described and shown in Figures 6-to-15.
Tenth The perforated air bridgesjjextending across the combustion chambers
in connection with air heating flues leading to their interiors, substantially as
herein before described and shown in Figures 6 to 15.
*
Eleventh The baffle bricks i į beneath the stove holes d d in connection with
the air bridges jj between the stove holes, for the purposes described and as shown
in Figures 6 to 15.
-Twelfth-The lining tiles pp held apart from the shell A by projections 9 9 so
as to form air flues, and flanged-plates MM holding the said tiles in place,
substantially as shown in Figures 8 and 9.
Thirteenth-The air heating flues L L and N extending along the walls of the
stove and communicating with perforated air bridges jj extending across the
combustion chambers substantially as hereinbefore described and shown in
Figures 6 to 15.
In witness whereof I the said John Clayton Mewburn have hereunto set my
hand and seal this twenty first day of July One thousand eight hundred and
eighty three
J. C. MEWBORN
(حمل)