An Improvement in the Construction of Gas Furnaces for Enamelling, Assaying, Hardening, Tempering, Melting, and the like.
Year: 1895

page_text: Date of Application, 8th Aug., 1895
Complete Specification Left, 7th May, 1896-Accepted, 13th June, 1876
PROVISIONAL SPECIFICATION.
An Improvement in the Construction of Gas Furnaces for
Enamelling, Assaying, Hardening, Tempering, Melting, and
the like.
1, FREDERICK WILLIS, Enameller, of 30, Richmond Crescent Richmond Road
Barnsbury London, N., do hereby declare the nature of this invention to be as
follows:-
An improvement in the construction of gas furnaces for enamelling assaying,
hardening, tempering, melting, etc., in which the heating agents may be coal gas
& air; spirit, naptha, or petroleum & air, with or without a blast, i.e., injecte!
into the furnace at a high pressure; the novelty in construction being in the case
of a muffle furnace for enamelling or assaying, in having an additional muffle
inserted between the working muffle & the furnace case, & the chimney or
outlet at the back of same, thus making the heating gases to pass from the front
along the bottom muffle to the back, to turn & pass over the back & sides of
same between that & the extra or covering muffle to the front, then to turn & pass
over the covering muffle between that & the furnace case to the chimney at the
back; in this way all the heat is gathered & retained working the furnace without
blast & with an atmospheric gas burner, the muffle can be raised to, & retained at
a brilliant heat, with a very small consumption for the size.
:
The same design is carried out in furnaces for melting, hardening & tempering;
in the case of the melting furnace, the crucible to be heated is suspended in the
centre of a cylindrical furnace casing, having the inlet at the bottom & the outlet
or chimney at the side, quite close to the bottom; round the crucible & between
it & the furnace casing is placed a cylinder of a shape suitable to the crucible to be
heated; thus the heating gases pass from the inlet, upward round the crucible,
between it & the cylinder to the top, then turn & pass downwards between the
cylinder & the furnace case to the bottom, to escape by the chimney.
Dated this 8th day of August 1895.
FREDERICK WILLIS.
An Improvement in the Construction of Gas Furnaces for
Enamelling, Assaying, Hardening, Tempering, Melting, and
the like.
I FREDERICK WILLIS, Enameller, of 30 Richmond Crescent, Richmond Road,
Barnsbury, London, N., do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained in
and by the following statement :-
This invention relates to an improvement in the construction of gas furnaces,
such as are employed for enamelling, assaying, hardening, tempering, melting and
the like in which the heating agents may be coal gas and air, spirit naphtha

page_text: or petroleum and air, with or without a blast, i.e. injected into the furnace at a high
pressure.
According to this invention, in the case of a muffle furnace, for enamelling or
assaying, I employ an additional mnffle, inserted between the working muffle and
the furnace case and the chimney or outlet at the back of the same, so as to make
the heating gases pass from the front along the bottom muffle to the back, thence
over the back and sides of same (between it and the extra covering muffle) to the
front, thence over the additional muffle to the back. In this way all the heat is
gathered and retained so that when the furnace is worked even without a blast,
and only with an atmospheric gas burner, the muffle can be raised to and retained at
a brilliant heat, with a very small consumption of gas, compared with the size of
the muffle.
:
The same principle can be applied to furnaces such as are used for melting
hardening and tempering. In the case of a melting furnace, the crucible is
suspended or otherwise suitably fixed in the centre of a cylindrical furnace casing
having the inlet at the bottom and the outlet or chimney at the side near the
bottom: round the crucible and between it and the furnace casing is placed a
cylinder of a shape suitable to the crucible to be heated, so that the heating gases
are made to pass from the inlet upwards, round the crucible, between it and the
cylinder, to the top, and then downwards, between the cylinder and the furnace
casing to the bottom-escaping by the chimney.
And in order that my said invention may be more clearly understood, I will now
proceed to describe the same, with reference to the drawing accompanying this
Specification, in which
Fig. 1 is an end elevation of a muffle furnace (with cover removed) such as
employed for enamelling, assaying hardening and tempering, constructed according
to my invention,
Fig. 2 shews a section through line A. B Fig. 1.
Fig. 3 is a vertical section of a furnace, such as is used for melting, constructed
according to my invention.
The same letters of reference are employed to denote the same parts in all the
views.
a shews the ordinary muffle, 6 additional muffle, inserted between the muffle a
and the furnace case c and chimney or outlet d.
In Fig. 3 e shews the crucible, resting on rod k in the furnace casing c, provided
with inlet fat bottom and outlet g at side.
Round the crucible e and between it and the furnace casing c, I place a
cylinder h.
The action of the heating gases is as follows:-
With reference to Figs. 1 and 2, the heated gases enter in at inlet / and pass
under and over the working muffle a and round the additional muffle b and out
at the outlet or chimney d-in the direction of the arrows' flight.
With reference to Fig. 3, the heating gases pass from the inlet, upwards round
the crucible e and between it and the cylinder h, and thence down the space formed
between the outside of the cylinder and the inside of the furnace casing c in the
direction of the arrows' flight.
It is understood that a chimney of such length as to create the necessary draught
must be attached to the outlet.
By constructing furnaces as above described, I obtain considerably more heating
surface than is the case with furnaces constructed as hitherto.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. The improvement in the construction of gas furnaces for enamelling, assaying,
hardening, tempering, melting and the like, substantially as herein before described
and for the nurnoso cot forth.

page_text: 2. In furnaces used for enamelling, assaying, hardening, tempering, melting and
the like, the employment of an additional muffle, for the purpose set forth.
Dated this Seventh day of May 1896.
BROWNE & Co.,
9 Warwick Court, Gray's Inn, London, W.C.,
Agents for the Applicant.