IMPROVEMENTS IN FURNACES
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by Thomas Frederick Cashin and
Joseph Green at the Office of the Commissioners of Patents, with
their Petition, on the 21st June 1869.
We, THOMAS FREDERICK CASHIN and JOSEPH GREEN, Engineers and
Iron Merchants, of 170 and 171, Gresham House, Old Broad Street, in
the City of London, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN FURNACES," to be as follows:-
Our said improvements relate to furnaces for heating, melting, and
working metals and glass, and for firing pottery ware and other such
purposes, more particularly to furnaces in which the fuel to be used is
ignitable vapour or gas injected into the furnace under pressure or by a
blast.
These improvements consist of a novel construction of the furnace
whereby we are enabled to draw off the products of combustion close
to the bed of the furnace. We form openings in the sides of the
furnaces through which the gaseous products pass; these openings are
fitted with valves, which work on horizontal axles, and according to the
direction in which they are set open or shut off communication with
vertical flues leading to horizontal flues at each end of the furnace. A
descending flue from the middle of each horizontal flue leads to zig-zag

page_text: flues beneath the furnace, which conducts the gases to the chimney flue
through a central flue, which is also litted with a valve similar in con-
struction and action to the valves herein-before mentioned. This central
flue valve regulates the ingress of the air and egress of the products of
combustion in such manner that when it is set in one direction, and the
valves controlling the outlets from the furnace are set to correspond, the
gaseous products of combustion pass from one end of the furnace to
the chimney, the air passing in a contrary direction through flues
leading to the other end of the furnace, but when the valves are reversed
the course of the air and of the waste gases are also reversed, the gascous
products passing off through the flues by which the air previously
entered, and the air entering by the flues through which the gases
previously passed. The walls of the flues may be formed with denti-
culated faces, and by adjusting the valves at the outlets from the furnace
and the central flue valve at the junction of the flues the draft can be
changed when desired, and the gases made to pass from either end or
from any angle of the furnace. A part of the products of combustion
may also be drawn off from any desirable point of the bed of the furnace
When the valves
by a subsidiary flue leading to the flues at each end.
at the end of the furnace are set in a direction corresponding with the
direction given by the central flue valve to the air passing from the main
shaft to support combustion the products of combustion are shut off
from that end, and the air passes upwards to another horizontal air
flue which passes around the furnace; from this small vertical shafts
fitted with dampers convey air to the jet of vapour or gas entering the
furnace. When a still soaking heat is desired the outlets from the furnace
are all opened, the central flue valve is set in a vertical position, the
descending shafts throttled by dampers, the air shut off from the main
shaft, and the air necessary to support combustion supplied by a sub-
sidiary channel, which may be formed beneath the bed of the furnace.
Another arrangement of our furnace consists in dispensing with the
central flue valve, and causing the products of combustion from cach
end and the air to pass in flues or channels side by side, the air carrying
back the waste heat given off through the bricks by conduction.