Improvements in and relating to Electric Furnaces.
Year: 1897

page_text: Date of Application, 11th June, 1897-Accepted, 8th Jan., 1898.
[Communicated from abroad by LA SOCIETÁ ITALIANA DEI FORNI ELETTRICI, 23
Via Fontanella di Borghese, Rome, in the Kingdom of Italy, Manufacturers. ]
Improvements in and relating to Electric Furnaces.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 322 High Holborn, in the County of Middlesex, 6, Lord Street,
Liverpool, and 6, Bank Street, Manchester, both in the County of Lancaster, and
Lower Temple Street, Birmingham, in the County of Warwick, Civil Engineer,
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:
The present application for Letters Patent relates to an improved construction
of electric furnace specially adapted for the carrying out of the process set forth
in Patent No. 13297 granted to Regnoli and others dated the 16th June 1896.
The furnace which forms the subject of the present application is however
obviously applicable also to other purposes.
In order to make the construction of the improved furnace more clear I will
describe the same with reference to the accompanying drawings in which:-
Figure 1 shows a vertical section through the furnace and feed mechanism
thereof.
"
Figure 2 shows a vertical section at right angles to the view shown in Figure 1.
In these drawings the same parts are indicated by like letters throughout.
A indicates the smelting hearth where the process of fusion takes place. It is
constructed in the shape of a truncated cone or pyramid with its broadest end
downwards. The walls a or sides of the hearth are lined with slabs of very re-
fractory material preferably graphite or carbon. The bottom of the furnace is
formed of a thick block B of graphite or the like supported upon a movable
metallic plate b which may be arranged to slide in suitable bearings by means
of appropriate mechanism hereinafter described. This graphite block forms the
lower electrode or anode of the apparatus. The current conductor is connected
to the metallic support b, by a suitable connection (not shewn in drawing). The
upper electrode or cathode C is preferably of prismatic shape and may be com-
posed of one or more pieces of carbon fitted together according to the dimensions
of the furnace. Its head is fixed to the metallic holder c and this in turn to the
tubular metal bar D adjustable in the bearing f attached to the cover plate d
and by means of which the position of C can be suitably adjusted. Above the
hearth A is provided a chamber E into which the electrode C can be drawn up.
This chamber E is preferably constructed of fire bricks and the cast iron cover d
aforesaid closes it hermetically at the top. The cover d fits upon the iron frame e
placed on the top of the fire brick chamber aforesaid.
The bearing through which the vertical bar D passes is rendered tight by a
suitable packing, such as asbestos or the like.
Around the hearth A of the furnace passes an annular chamber F constructed

page_text: of refractory material and enclosing on three sides the space G. This space G
communicates by suitable holes with the heart of the furnace, and through the
said holes the gases such as carbonic oxide and the like produced in the interior
of the furnace pass into the space G and maintain the outer chamber at a high
temperature, thus diminishing the radiation and consequently maintaining the
temperature of the smelting furnace.
From G the pipe h conveys the carbonic oxide or other gases to suitable purify-
ing and storage receptacles. The space between the fourth side of the smelting
hearth A and the outside of the chamber F has no communication with the
space G. Herein is placed a gas burner I to which the carbonic oxide generated
is led from the gas holder through a pipe. The combustible gas being burnt at
this point serves to heat the inclined tube H through, which the materials to be
treated in the furnace are delivered from the hopper M by means of the archimedean
screw N and these materials are thus rendered more quickly fusible by the action
of the furnace. This tube H is also constructed of refractory material and is
preferably formed of elliptic section having its greater axis in the horizontal
direction so that the material passes through it in a comparatively thin layer.
The combustion products from the gas burner I pass away through the tube /
to the chimney and the air requisite for combustion is introduced through the
holes m.
The furnace is supported on a bed of masonry having below it a tunnel
as shown. The lever Q hinged in the support sliding between the guides ?
and is hinged to the base plate b. The lever Q is normally maintained in posi-
tion by a hook T engaging in a suitable catch as shown in the drawing.
it is desired to discharge the furnace the lever Q is lifted up and the furnace
base consequently lowered whereupon the carbide or other product produced in
the furnace falls down and collects in a reservoir beneath. A chimney or tube is
provided to withdraw the carbonic oxide or other gas given off by the product
during the drawing. The piece is guided in its movements by the guides s.
electric current is supplied to the cathode C by a suitable conductor passing
through the tube D.
When
The
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:
1. In an electric furnace the arrangement of a heating chamber around the
hearth of the furnace, into which the heated gases produced at the hearth
pass
and circulate before leaving the furnace, thus assisting in maintaining the tem-
perature of the hearth.
2. In an electric furnace, the arrangement for the utilisation of the gaseous
products to heat the materials to be treated in the furnace consisting in passing
the furnace gases through a flue in which they return a proportion of their heat
to the furnace, then passing them through suitable purifying and collecting
apparatus, and finally returning them to the furnace to be ignited beneath the
inclined tube through which the materials are delivered to the hearth of the
furnace, substantially as described.
3. The improved electric furnace constructed substantially as described with
reference to the accompanying drawings.
W. P. THOMPSON & Co.,
322 High Holborn, London, W.C., Patent Agents for the Applicant.