IMPROVED AIR HEATING FURNACE OR APPARATUS
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at
the Office of the Commissioners of Patents, with his Petition,
on the 14th November 1872.-A communication from abroad by
Stephen Johnson Gold, of Cornwall, in the County of Litchfield,
and State of Connecticut, United States of America.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature
of the said Invention for "IMPROVED AIR HEATING FURNACE OR APPARATUS,"
to be as follows: -
This Invention has for its object to improve the construction of
that class of heaters, such as furnaces, fire-place heaters and stoves,
that do their work by heating air and discharging it into the apartment
to be warmed, in such a way as to make said heaters simple in
construction, durable, not liable to get out of order, and which shall
be so constructed as to prevent automatically the temperature from
rising above the point for which the heater may be adjusted.
And it consists in the combination of the pockets or open side
flues, constructed as herein-after more fully described, with the
openings in the base plate in combination with the open pockets

page_text: and the openings in the base plate, the arrangement of the fire-pot
within the combustion chamber, in the combination of the side pockets,
the openings in the base plate and the cold air plate, in the combination
of the wedges with the curved plates and the base plate and the top
plates, either or both, in the combination of the heat regulating
device berein-after fully described with the furnace, in the combination
of the adjustable cold air pipes with the water box or boiler of the
heat regulating device, and in the arrangement of the smoke pipe
within the combustion chamber, and in connection with the curved
plates, base plate, and top plate of the furnace, as herein-after more
fully described.
The base plate is cast with an opening in its centre to receive
the fire-pot, and with flanges to receive the lower ends of the plates
that form the pockets, with openings for the products of combustion
to pass through, and with other openings for the cement to be inserted.
The top plate is made without the draft openings, but with the
central opening and the flanges and openings corresponding with
the flanges and the last named opening of the lower or base plate.
Both plates have also an opening for the smoke pipe to pass through,
which openings are so located that the smoke pipe may be wholly
within the combustion chamber and upon the opposite side of the
fire-pot from the doors. The side plates that form the pockets are
are made in U or V shape, and are so arranged that the plane of their
sides if extended would pass through the fire-pot upon the opposite
sides of and equally distant from the centre of said fire-pot.
-
By this arrangement no single plate will be fully exposed to the
full radial heat of the fire, and the radial rays of heat from the fire
will strike the forward or inner parts of the plates at such an inclination
as to be reflected into the outer parts of the pockets, so that the entire
plates may be heated uniformly. This prevents any portion of the
air from being burned or scorched by coming in contact with the
metallic surface unduly heated, and thus rendered unfit for respiration.
The contiguous edges of the adjacent plates are bolted or otherwise
secured to each other so to present an edge to the fire. The said
plates are continuous all around the fire-pot except in front, where the
doors are placed. The plate upon the side opposite to the doors is
made larger so as to form a pocket so large that the smoke pipe
can pass up through it. By this arrangement the column of air within

page_text: the pipe will become heated so as to make a strong draft through
said pipe.
The lower ends of the side plates are placed around the flanges
of the base plate, where they are secured in place by wedges driven
in along the surface of the base plate between the adjacent plates.
These wedges are ribbed to increase their strength and at the same
time secure space for the cement. The upper ends of the side
plates are similarly secured to the top plate. The wedges are further
secured to the top and base plates by bolts, and the said plates are
connected to each other by long bolts. A flue is formed beneath
the base plate, into which the draft openings and the stove pipe
opening lead. In using the heater as the heat and other products
of combustion rise from the fire-pot, the heavy gases roll over the edge
of the fire-pot and pass directly into the flue. The heat and lighter
or combustible gases rise through the fire chamber, enter and pass
down through the pockets formed by the side plates, parting with
their heat to said plates so as to become comparitively cool before
they pass into the flue formed beneath the base plate, whence they
pass through the smoke pipe to the chimney.
In bottom draft heaters the openings in the base plate in the bottoms
of the pockets may be of uniform size, as the products of combustion
will pass down evenly upon all sides of the fire-pot, and their
combined area should be about equal to the area of the stove pipe
opening.
In front draft heaters where the tendency of the heated products
of combustion is to pass into the rear part of the fire chamber, the
said openings are made small near the smoke pipe and gradually
increase in size towards the front, so that the said products of com-
bustion may pass through all the openings in equal quantities, thus
insuring the uniform heating of the air in the air chamber. A ring
plate rests upon supports at suitable distances apart, and extends from
the outer wall of the air heating chamber to the outer parts of the
vertical plates or pockets. The ring plate flares downward and is
designed to cause all the air that enters the air heating chamber,
and which is introduced beneath said plate, to enter through the spaces
between the curved side plates or pockets, thus insuring its contact
with said plates. A small water and steam-tight box or boiler capable
of containing a quart or more of water is connected with the end of a

page_text: steam pipe which may pass over the top of the furnace or over some
other support, and passes out at the front of the furnace at such
a height as to be entirely out of the way. With the projecting
end of the steam pipe is connected a steam chest within which is
placed a piston or diaphragm. With the piston or diaphragm is
connected a rod which passes out through a hole in the top of the
steam chest, and to its upper end is pivoted a lever which is pivoted
to and supported by a bracket or other support, and to its extremities
are attached chains, one of which is connected with the fire-door and
the other with the draft door. By this construction when the air
in the air heating chamber becomes heated to such a temperature
that steam is formed in the boiler the steam passes along the pipe.
and raises the piston or diaphragm which operates the lever and
opens the fire-door, admitting cool air into the fire chamber, checking
combustion, and at the same time closing the draft door still further
checking combustion.
As the formation of steam is stopped the piston descends and the
said doors return to their former position; the heater being thus self
regulating to keep a uniform temperature.
A pipe open at both ends is inserted in the brickwork or wall
of the air chamber in such a position that its inner end may be
close to and directly opposite the side of the box or boiler. In the
outer part of this pipe is inserted a pipe open at its inner end and
closed at its outer end, and having a number of holes in its sides.
By drawing this inner pipe outward so as to uncover one or more
of its holes a stream of cold air smaller or larger according to the
extent to which the pipe is drawn out is projected against the boiler so
as to keep down its temperature and allow the air in the air heating
chamber to increase in temperature to two hundred and forty or
even three hundred degrees before the formation of steam in the
boilers begins, thus enabling the temperature of the heated air to
be regulated as required.