IMPROVEMENTS IN STEAM BOILER FURNACES AND OTHER FURNACES
Year: 1876

page_text: LETTERS PATENT to John Cornforth, of Birmingham, in the County of Warwick,
Licensed Victualler, for the Invention of "IMPROVEMENTS IN STEAM BOILER
FURNACES AND OTHER FURNACES."
Scaled the 28th November 1876, and dated the 12th June 1876.
PROVISIONAL SPECIFICATION left by the said John Cornforth at the Office of
the Commissioners of Patents on the 12th June 1876.
JOHN CORNFORTH, of Birmingham, in the County of Warwick, Licensed Victualler.
"IMPROVEMENTS IN STEAM BOILER FURNACES AND OTHER FURNACES."
My Invention consists of the improvements herein-after described in steam boiler
furnaces and other furnaces, the objects of my said improvements being principally
to effectually prevent the formation of smoke and to economize the consumption of
fuel in the said furnace.
I will describe my Invention as applied to the furnace of a steam boiler, but my
said Invention as herein-after pointed out may also be applied to other furnaces.
I make the fire-bars of the fire-grate of the furnace of tubes of wrought iron,
steel, or other metal or alloy capable of resisting the heat of the furnace, the said
hollow or tubular fire-bars being supported on cross bearers similar to those by
which ordinary solid fire-bars are supported. The front ends of the tubular or
hollow fire-bars are open to the air near the fire-door of the grate, and the rear ends
open into a hot air flue or chamber at the back of and crossing the end of the fire-
place. At each side of the fire-place and parallel with the longer sides of the said
fire-place are two parallel flues. These side parallel flues communicate with one
another at the front of the furnace, and the outer flue or the one most distant from
the fire-place opens into a cross flue at the back of the furnace and communicates
with the stack at the middle of the said back flue. The flame and products of
combustion from the fire-place, together with heated air supplied in the manner
herein-after explained, circulate about these side flues before they pass to the stack
of the furnace. The hot air flue or chamber at the back of the fire-place is provided
with curved ends, the said ends opening into the inner side flues near their junction
with the back of the fire-place. Atmospheric air entering the tubular fire-bars at
their open front ends passes through thom into the hot air chamber at the rear ends
of the said fire-bars, the said air being heated in its passage through the said bars.
[Price 6d.]

page_text: The heated air thus supplied to the air flue or chamber mixes with the products of
combustion in the inner side flues of the furnace, as the said products issue from the
fire-place and their perfect combustion is thereby ensured. By the perfect combustion
which is thus obtained in the furnace the production of smoke is prevented and
a saving of fuel effected. By means of a slide or valve the quantity of atmospheric
air passing through the hollow or tubular fire-bars from the front of the grate may
be regulated at pleasure. By the passage of the cold air through the fire-bars the
said fire-bars are kept cool and thereby preserved, and the formation of clinkers on
the said fire-bars prevented.
For the purpose of regulating the draught through the fire-place, and increasing
or moderating the combustion of the fuel on the fire-grate, I arrange at the back of
the fire-place a regulating plate or damper turning on a hinge joint and worked by
a rod from the front of the furnace. This hinged plate or damper may either be
raised from the back of the fire-place or be turned down upon the said back. When
the said plate is in the first described position there is a free communication between
the back of the fire-place and the side flues of the furnace, but when the said plate
is in the last described or turned down position it nearly cuts off communication
between the fire-place, and the side flues and the draft through the fire-place is
thereby moderated and the combustion of the fuel reduced.
Besides steam boiler furnaces my improvements may be applied among others to
the furnaces of muffles, annealing pots, melting pots, or crucibles, and the like, for
preventing the formation of smoke and for economizing fuel.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Cornforth in the Great Seal Patent Office on the 4th December
1876.
JOHN CORNFORTH, of Birmingham, in the County of Warwick, Licensed Victualler.
"IMPROVEMENTS IN STEAM BOILER FURNACES AND OTHER FURNACES."
My Invention consists of the improvements herein-after described in steam boiler
furnaces and other furnaces, the objects of my said improvements being principally
to effectually prevent the formation of smoke and to economize the consumption of
fuel in the said furnaces.
I will describe my Invention as applied to the furnace of a steam boiler, but my
said Invention, as herein-after pointed out, may also be applied to other furnaces.
I make the fire-bars of the fire-grate of the furnace of tubes of wrought iron, steel,
or other metal or alloy capable of resisting the heat of the furnace, the said hollow
or tubular fire-bars being supported on cross bearers similar to those on which
ordinary solid fire-bars are supported. The front ends of the tubular or hollow
fire-bars are open to the air near the fire-door of the grate, and the rear ends open
into a hot air flue, chamber, or hollow bridge at the back of and crossing the end
of the fire-place. At each side of the fire-place and parallel with the longer sides
of the said fire-place are two parallel flues. These side parallel flues communicate
with one another at the front of the furnace and the outer flue, or the one most
distant from the fire-place opens into a cross flue at the back of the furnace and
communicates with the stack. The flame and products of combustion from the
fire-place, together with heated air supplied in the manner herein-after explained,
circulate about these side flues before they pass to the stack of the furnace. The
side flues described need not be used, and the flame and products of combustion
be made to circulate about flues of the ordinary kind. Atmospheric air entering
the tubular fire-bars at their open front ends passes through them into the hot air
chamber or hollow bridge at the rear ends of the said fire-bars, the said air being
heated in its passage through the said bars. The heated air thus supplied to the
air flue, chamber, or hollow bridge, mixes with the inflammable gases from the fire-
place passing over the said hot air chamber or bridge, and their perfect combustion

page_text: is thereby ensured. Or the heated air may be delivered directly to the flue behind
the bridge. By the perfect combustion which is thus obtained in the furnace the
production of smoke is prevented and a saving of fuel effected. By means of a slide
or valve the quantity of atmospheric air passing through the hollow or tubular fire-
bars from the front of the grate may be regulated at pleasure. By the passage of
cold air through the fire-bars the said fire-bars are kept cool and thereby preserved,
and the formation of clinkers on the said fire-bars prevented.
I will now proceed to describe with reference to the accompanying Drawing the
manner in which my Invention may be performed.
Figure 1 represents in longitudinal section and Figure 2 in cross section the
furnace of an egg-ended steam boiler, the parts of which are constructed and com-
bined or arranged according to my Invention; Figure 3 represents in longitudinal
section and Figure 4 in cross section my improvements applied to the furnace of a
Cornish or tubular boiler; Figure 5 represents in side elevation, end elevation,
and longitudinal section, one of the hollow or tubular fire-bars of the furnace drawn
to a larger scale. The same letters of reference indicate the same parts in the
several Figures of the Drawing.
a is the fire-place of the furnace, b is the ash-pit, is the hot air flue chamber
or hollow bridge at the back of the fire-place a; d, d, are the fire-bars of the fire-
grate made of tubes of wrought iron, steel, or other metal or alloy capable of
resisting the heat of the furnace. These tubular or hollow fire-bars d, d, are
supported at the front and back of the fire-place by the cross bearers e, f. The
front bearer e is provided with a series of nearly semicircular notches or depressions
in which the ends d² of the fire-bars beyond the collars ³ (see Figure 5) engage,
and the back bearer f has a series of circular holes in it, in which the ends d' in
front of the collars are inserted, the said collars and d serving as stops to
the said fire-bars. The front ends of the tubular or hollow fire-bars d are open
to the air in the ash pit b near the fire-door of the grate, and the rear ends of the
said fire-bars d open into the hot air flue, chamber, or hollow bridge c. On the
under-side of the dead plate g near the front open ends of the tubular fire-bars &
is a guard plate or shield h. By means of this guard plate or shield the fuel fed
to the fire-grate through the fire-door i is prevented from being thrown into and
choking the said hollow fire-bars. Atmospheric air entering the tubular fire-
bars d, d, at their open front ends passes through them into the hot air flue,
chamber, or hollow bridge c at the rear ends of the said fire-bars. The heated air
thus supplied to the air chamber or hollow bridge c rises up the said chamber or
bridge and mixes with the inflammable gases passing over the said hot air chamber
or bridge, and ensures their perfect combustion and the prevention of smoke.
The hot air chamber, flue, or bridge c may be constructed to deliver the hot air
to the inflammable gases either in the form of jets or in a sheet or sheets.
When it is desired to deliver the air in jets the hollow bridge or air chamber is
divided by vertical divisions so as to form a series of vertical channels into which
the rear ends of the tubular fire-bars respectively open. A slide or valve at the
front ends of the tubular fire-bars, as herein-after described, may be used to regulato
the quantity of atmospheric air passing through them to the hot air chamber or bridge.
The flame and heated air passing over the hot air chamber or bridge from the fire-
place circulate first along the central flue of the boiler, and afterwards circulate
about the side flues 1, 1, and from thence escape to the stack.
In egg-ended boiler furnaces, as represented in Figures 1 and 2, the flame and
heated air instead of passing directly into the central fluck may pass into a cross
flue behind the hollow bridge or air chamber c, and this cross flue may communicate
with a series of parallel side flues, through which side flues the flame and heated
air circulate. And instead of the heated air passing through the hollow fire-bars
being delivered to the inflammable gases from the fire-place a by means of a hollow
bridge or air chamber, as represented, the said heated air may be delivered at tho
back of a solid bridge to mix with the inflammable gases entering the central flue
or the cross flue herein-before described. Or the hollow bridge or air chamber,

page_text: represented in the Drawing, may be used in combination with the last described
arrangement, that is to say, heated air may be delivered both at the top of the
bridge and at the back of the said bridge. When heated air is delivered at
the back of the bridge the hollow or tubular fire-bars are continued through the
said bridge or pipes from the hollow bridge open to the back of the said bridge.
In order to regulate the admission of air to the tubular fire-bars I prefer to fix a
door in front of the ash pit, by opening or closing which door, more or less, the
required quantity of air may be admitted. The apparatus may be made automatic
by connecting the door with a hollow cylinder on the boiler, the said cylinder having
a loaded piston which is raised when the pressure of the steam exceeds the required
pressure, and by its rising closes the ash-pit door, more or less, until the diminished
supply of air causes the pressure of steam to sink to the required pressure.
Besides steam boiler furnaces my improvements may be applied among others to
the furnaces of muffles, annealing pots, melting pots or crucibles, drying stoves,
stoves for heating apartments and the like, for preventing the formation of smoke
and for economizing fuel.
Having now described the nature of my Invention, and the manner in which the
same is to be performed, I wish it to be understood that I do not limit myself to
the precise details herein described and illustrated, as the same may be varied
without departing from the nature of my Invention. But I claim as my Invention
the combinations or arrangements of the parts of steam boiler and other furnaces,
herein-before described and illustrated in the accompanying Drawing, whereby the
formation of smoke is prevented and the consumption of fuel economized.
In witness whereof, I, the said John Cornforth, have hereunto set my hand and
seal, this Twenty-ninth day of November, in the year of our Lord One thousand
eight hundred and seventy-six.
Witness,
RICHARD SKERRETT,
Clerk to George Shaw,
Birmingham.
JOHN CORNFORTH. (Ls.)