IMPROVEMENTS IN FURNACES AND FIRE-PLACES FOR BURNING SLACK, AND IN STEAM BOILERS COMBINED THEREWITH
Year: 1877

page_text: LETTERS PATENT to Frederick Hart, of 59, Tavistock Road, Westbourne
Park, in the County of Middlesex, for the Invention of "IMPROVEMENTS IN
FURNACES AND FIRE-PLACES FOR BURNING SLACK, AND IN STEAM BOILERS
COMBINED THEREWITH."
Sealed the 7th August 1877, and dated the 28th February 1877.
PROVISIONAL SPECIFICATION left by the said Frederick Hart at the Office
of the Commissioners of Patents on the 28th February 1877.
FREDERICK HART, of 59, Tavistock Road, Westbourne Park, in the County of
Middlesex. "IMPROVEMENTS IN FURNACES AND FIRE-PLACES FOR BURNING SLACK,
AND IN STEAM BOILERS COMBINED THEREWITH."
This Invention has for its objects improvements in furnaces and fire-places for
burning slack, and in steam boilers combined therewith.
The steam boiler consists of an upright cylinder or cylindrical shell, closed at the
top and bottom, and within it there is a drum of similar form and of such dimen-
sions as to leave a water space all round between the shell and the drum within it.
There is also a space over the top of the drum such as to provide adequate accom-
modation for the steam and permit at the same time of the top of the drum being
always covered by the water in the boiler. Vertical water tubes pass through the
drum from top to bottom; the furnace communicates with the interior of the drum
by a slit or opening formed partly around the bottom and lower part of the side of
the drum, and at a point opposite to this slit or opening there is another passage
through the drum and the outer shell leading from the interior of the drum to the
chimney.
In order to accommodate the furnace the outer shell of the boiler is cut away at
the part corresponding to the slit or opening in the drum, and here the shell is
connected with the side of the drum in such manner as to form a hanging bridge
extending partly around the boiler. At this part also the bottom of the drum is
connected with the outer bottom, and so a cavity is formed extending partly under-
neath the boiler. This cavity serves as an ash pit; the ash pit, however, extends
beyond the outer shell of the boiler fire-bars from the top of it, and it is closed un-
derneath by doors so that there is no free admission of air beneath the fire-bars.
Prine B22

page_text: The parts of the fire-bars which project beyond the outer shell of the boiler are
inclined upwards so that their outer ends rise as high as the under surface of the
hanging bridge.
At some distance above the fire-bars there is a hopper to receive small coal or
slack to feed the fire, and the fuel descends from this hopper through a comparatively
narrow channel, which, however, widens rapidly as it approaches the part of the
furnace where the small coal commences to swell with the heat. Between the
lower end of this channel and the fire-bars the fuel forms a heap resting upon the
fire-bars and against the outer side of the hanging bridge; on the outer side of the
heap curved bars or plates are provided to keep the heat within due bounds so that
there may not be too great a thickness of fuel, but these bars or plates are arranged
to obstruct as little as possible the free access of air to the outer side of the heap.
The small fuel coheres in the lower part of the channel loading from the hopper and
forms lumps between which afterwards the air is able to pass freely. The fuel so
caked into lumps forms a heap on the fire-bars, and the air striking downwards
through the outer side of this heap, and passing through it and beneath the
hanging bridge, effects the combustion. The ashes fall through the spaces between
the fire-bars into the ash pit, and are removed from time to time.
I case in the channel descending from the hopper and also the front of the pile of
fuel, and cause the air to pass through the casing around this channel as it goes to
supply the combustion; thus the channel is kept cool up to the point at
which it is desired that the heating should commence, and partially heated air
is supplied to the fire; loss of heat by radiation is also lessened.
:
. Furnaces and fire-places constructed substantially as above described may be
applied to other uses as well as to the heating of steam boilers.
The furnace or fire-place, as constructed without the steam boiler, consists of,
first, a throat or narrow channel for the slack to descend to the furnace; the lower
end of this channel widens rapidly as it approaches the part of the furnace where
the slack commences to swell with the heat; immediately below the mouth of the
channel, both at the front and back, or all round, are placed inclined or level bars
still following up the shape of lower end of the channel; the air passing through
these.bars becomes mixed with the gas given off by the coaking coal and passes
downward through the incandescent part of the fire. At the bottom of these bars
there is a fire-brick or water bridge at both back and front, or only at the
back, as desired; the lower edge of this bridge is some distance below the point
where the coal looses all its gas. At a sufficient distance below the bridge to allow
the required area for the escape of the products of combustion is the floor of the
furnace, which floor extends beyond the bridge or bridges to rather more than the
height of the bridge from the floor.
In the floor are narrow slits to allow the ashes to fall into the ash pit. No air
nasses un through these slits.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederick Hart in the Great Seal Patent Office on the 28th August
1877.
FREDERICK HART, of 59, Tavistock Road, Westbourne Park, in the County of 4
Middlesex. "IMPROVEMENTS IN FURNACES AND FIRE-PLACES FOR BURNING SLACK,
AND IN STEAM BOILERS COMBINED THEREWITH."
This Invention has for its objects improvements in furnaces and fire-places for
burning slack, and in steam boilers combined therewith.
The steam boiler consists of an upright cylinder or cylindrical shell closed at the 5
top and bottom, and within it there is a drum of similar form, and of such dimen-
sions as to leave a water space all round between the shell and the drum within it.

page_text: There is also a space over the top of the drum such as to provide adequate accom-
modation for the steam, and permit at the same time of the top of the drum being
always covered by the water in the boiler. Vertical water tubes pass through the
drum from top to bottom, The furnace communicates with the interior of the drum
by a slit or opening formed partly around the bottom and lower part of the side of
the drum, and at a point opposite to this slit or opening there is another passage
through the drum and the outer shell leading from the interior of the drum to the
chimney.
In order to accommodate the furnace the outer shell of the boiler is cut away at
the part corresponding to the slit or opening in the drum, and here the shell is
connected with the side of the drum in such manner as to form a hanging bridge
extending partly around the boiler. At this part also the bottom of the drum is
connected with the outer bottom, and so a cavity is formed extending partly under-
neath the boiler. This cavity serves as an ash pit; the ash pit, however, extends
beyond the outer shell of the boiler fire-bars from the top of it, and it is closed
underneath by doors so that there is no free admission of air beneath the fire-
bars. The parts of the fire-bars which project beyond the outer shell of the boiler
are inclined upwards so that their outer ends rise as high as the under surface of
the hanging bridge.
At some distance above the fire-bars there is a hopper to receive small coal or
slack to feed the fire, and the fuel descends from this hopper through a compa-
ratively narrow channel, which however widens rapidly as it approaches the part of
the furnace where the small coal commences to swell with the heat. Between the
lower end of this channel and the fire-bars the fuel forms a heap resting upon the
fire-bars and against the outer side of the hanging bridge; on the outer side of the
heap curved bars or plates are provided to keep the heat within due bounds so
that there may not be too great a thickness of fuel; but these bars or plates are
arranged to obstruct as little as possible the free access of air to the outer side of
the heap. The small fuel coheres in the lower part of the channel leading from the
hopper, and forms lumps between which afterwards the air is able to pass freely.
The fuel so caked into lumps forms a heap on the fire-bars, and the air striking
downwards through the outer side of this heap and passing through it and beneath
the hanging bridge affects the combustion. The ashes fall through the spaces
between the fire-bars into the ash pit and are removed from time to time.
I case in the channel descending from the hopper, and also the front of the pile
of fuel, and cause the air to pass through the casing around this channel as it goes
to supply the combustion; thus the channel is kept cool up to the point at which
it is desired that the heating should commence, and partially heated air is supplied
to the fire; loss of heat by radiation is also lessened.
Furnaces and fire-places constructed substantially as above described may be
applied to other uses as well as to the heating of steam boilers.
The furnace or fire-place as constructed without the steam boiler consists of,
first, a throat or narrow channel for the slack to descend to the furnace; the lower
end of this channel widens rapidly as it approaches the part of the furnace where
the slack commences to swell with the heat; immediately below the mouth of the
channel are placed inclined or level bars still following up the shape of lower end of
the channel; the air passing through these bars becomes mixed with the gas given
off by the coking coal and passes downward through the incandescent part of the
fire. At the bottom of these bars there is a fire-brick or water bridge; the lower
edge of this bridge is some distance below the point where the coal looses all its
gas. At a sufficient distance below the bridge to allow the required area for the
escape of the products of combustion is the floor of the furnace, which floor
extends beyond the bridge or bridges to rather more than the height of the bridge
from the floor.
In the floor are narrow slits to allow the ashes to fall into the ash pit; no air
passes up through these slits,

page_text: In order that my said Invention may be most fully understood and readuy carried
into effect I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical section of a steam boiler and furnace constructed according
to my Invention. Figure 2 is a horizontal section of the same taken above the
level of the feed hopper and furnace; a is the cylindrical shell of the boiler, and b
the drum within it; c, c are water tubes passing through the drum; d is the
opening at the bottom of the drum forming the connection between its interior and
the furnace; e is the outlet by which the products of combustion after that they
have been deflected upwards by a screen to cause them to play amongst the tubes
pass away to the chimney; f₁f are bars upon which the fire rests, but no air is
permitted to pass between them as the space or ash pit g beneath should be closed
air tight when the furnace is at work, so that the apertures between the bars f
serve only to permit the ash from the fuel to fall through, and not as is usual in
furnaces for the supply of air to the fuel. Neither does the flame from the fucl
descend between these bars as in some furnaces heretofore proposed, so that the
bars are not liable to be burnt away. h is the feed hopper; it is so far removed
from the fire that there is no risk of the fuel which it contains becoming heated,
which would cause it to cake so as to impede its descent; i is the throat descending"
from the bottom of the hopper; it tapers at first slightly, but as it reaches the
region where the fuel swells it opens out rapidly so that the passage may not
become blocked. The feed hopper is supplied by preference with small bituminous
coal, which by the means described becomes agglomerated into lumps before it is
brought into contact with the air by which its combustion is effected. k, k are
lateral fire-bars which serve to confine the fuel after it escapes from the neck of the
hopper whilst allowing free access of air to it; 1 is an inverted bridge compelling
the air entering between the bars k to take a downward direction so that it may
carry with it the gases which the fuel liberates in the region of the throat and
conduct them down amongst incandescent fuel which has already been deprived of
its gaseous constituents; m is a casing surrounding the hopper and throat and
serving to lead an air current around them to keep them cool; the air is afterwards
cansed to enter the hollow screen n in which it circulates and becomes heated, after
which it is employed to effect the combustion of the fuel. Furnaces constructed as
above described may be employed for other purposes besides the heating of steam
boilers, and in such cases the bridge will usually be formed in fire-brick, although a
water bridge may be employed. Steam boilers of the construction above described
may also, according to my Invention, be employed in connection with other
furnaces, but I prefer to employ my boiler and my furnace in combination as
described.
Figure 3 is an elevation, and Figure 4 is a transverse section of a kitchen range
constructed according to my Invention. As in Figures 1 and 2 f, f, are bottom bars
which serve only for the fuel to rest upon and to allow the ash to fall through;
there is a drawer beneath in which the ash is received, and this drawer can be
taken out and emptied from time to time; h is the feed hopper, and i is the throat;
k, k, are the fire-bars by which air is admitted to the fuel; in this arrangement
such bars are provided both at the front and back, and at the front a rising and
falling door is fitted by means of which the draught through the bars can be cut
off when there is no cooking going on in front of the fire; 7 is an inverted bridge
of fire-brick beneath which the flame of the fire has to pass, and the heated
products of combustion then circulate around ovens and they rise up a flue at the
back leading to the chimney.
Figure 5 is a sectional elevation of a range similar to that just described, except
that the fire-bars k are arranged on the right and left of the fire in place of at the
front and back.
Stoves or fire-places may be constructed in the manner here described in cases where
ovens are not required.

page_text: Figure 6 is a sectional elevation showing my Invention adapted to a water heater
or boiler. Here the place of the fire-bars k is taken by a series of rings k¹ arranged
within in place of exterior to the heap of descending fuel. The boiler is annular
and surrounds the fire, and the bottom of the boiler forms the bridge beneath
which the flame has to pass; it rises on the exterior of the boiler and so passes to
the chimney. The air to supply combustion descends to the rings k¹ by the pipe j
passing down through the hopper and throat. As in the other arrangements ƒ, f,
are bottom bars serving only to hold up the fuel and to allow the ash to pass
through.
Having thus described the nature of my said Invention, and the manner of per-
forming the same, I would have it understood that I claim,-
First. The combination of the feed hopper with its narrow throat widening as it
descends, the lateral air supply between fire-bars or in other equivalent manner
beneath the throat, and the inverted bridge below so arranged that the air entering
the fire mixes with the gases liberated from the fuel and carries them downwards
amongst incandescent fuel from which the gas has already been driven off, all sub-
stantially as herein described.
Second. The construction of steam boilers and furnaces substantially as herein
described.
Third. The construction of kitchen ranges and other fire-places substantially as
herein described.
In witness whereof, I, the said Frederick Hart, have hereunto set my hand
and seal, this Twenty-seventh day of August, in the year of our Lord
One thousand eight hundred and seventy-seven,
HART