IMPROVEMENTS IN AND RELATING TO GAS FURNACES CHIEFLY DESIGNED FOR MELTING TIN AND SPELTER
Year: 1884

page_text: Wo THOMAS EDWIN EDWARDS of Birkenhead, in the County of Chester,
Galvanized Iron Manufacturer, JOHN WILLIAM CARTWRIGHT HOLMES, of Hudders-
field and BENJAMIN MIDGLEY of Milnsbridge, both in the County of York, Gas
Engineers; do hereby declare the nature of our invention for "IMPROVEMENTS
IN AND RELATING TO GAS FURNACES CHIEFLY DESIGNED FOR MELTING TIN AND
SPELTER" to be as follows:
Our invention relates to furnaces for melting tin, spelter, and other metals by
means of gas.
Metals have heretofore been melted in furnaces heated by gas, but in these cases
the gas has usually been admitted through burners or pipes within the furnaces,
which burners or pipes-by reason of the intense heat required for the process
were frequently melte.J.
The object of our invention is to dispense with the use of burners and pipes
within the furnace and to construct the furnace in such a manner that any intensity
of heat can be obtained, and utilized in the most effective manner. To this end
the air and gas are mixed before entering the furnace to which they are admitted
in volume. The air and gas are admitted below the vessel in which the metal is
melted, through one or more discs of wire-gauze in order to thoroughly mix them.
A small pipe connected with the gas pipe extends in front of the gas and air inlet.
The gas passing through this small pipe, when lighted, serves to ignite the mixture
of air and gas for heating the furnace.
Divisions or flues are formed around the melting pan so that the heat is caused
to pass several times over the same before leaving the furnace.
With this arrangement the furnace may be entirely enclosed so that no vapours
can escape. The furnace may be covered externally with asbestos or other non-
conducting material, the outside of the furnace thus remaining much cooler and .
easier to work at, than heretofore.

page_text: In some cases it may be desirable for a manufacturer to make the gas necessary
for heating the furnace as he can afterwards use the ammonia, tar, coke, and other
residual products.
The advantages of this invention are that the metal can be kept at an uniform
heat, thereby preventing the excessive accumulation of dross; the frequent cleaning
of the furnaces is rendered unnecessary; the pans.or baths can be made of thinner
metal than when designed to be heated by coal or coke; and the furnace being
entirely closed no sulphurous vapours escape among the work-people to injure their
health.
1004

page_text: COMPLETE SPECIFICATION.
We, THOMAS EDWIN EDWARDS, of Birkenhead, in the County of Chester,
Galvanized Iron Manufacturor, JOHN WILLIAM CARTWRIGHT HOLMES, of Hudders
field, and BENJAMIN MIDGLEY, of Milnsbridge, both in the County of York, Gas-
Engineers do hereby declare the nature of our invention for "IMPROVEMENTS
IN AND RELATING TO GAS-FURNACES, CHIEFLY DESIGNED FOR MELTING TIN AND
SPELTER " and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :—
Our invention relates to, gas-furnaces chiefly designed for melting tin and spelter.
Furnaces have heretofore been constructed for melting such metals by means of
gas, but the gas is usually admitted to these furnaces through burners or pipes
which extend more or less into the furnace, and are, therefore, liable to be melted
by the intense heat required for carrying on the process.
Our invention is designed to provide for uniformly maintaining the heat in the
furnace at any required degree of intensity without liability to injury of the
furnace or parts connected therewith, and for utilizing the heat therein in a more
effective manner than heretofore. Moreover, by our invention, we are enabled to
dispense with the ordinary burners or pipes which extend into the furnace.
In our improved apparatus, air and gas are intimately mixed, and the mixture
thereof is admitted into the furnace in a considerable volume in the manner
hereinafter described, instead of in the form of jets as in the furnaces heretofore
constructed.
In the accompanying drawing, we have shewn how our said invention may be
conveniently and advantageously carried into practice.
Figure 1 is a vertical longitudinal central section of our apparatus.
Figure 2 is a horizontal section on the line a, a, Figure 1, and
Figure 3 is a vertical section on the line y, y, Figure 1.
a indicates the bath, pan or vessel in which the tin or spelter is to be melted.
This vessel is surrounded by walls b of fire-brick and by a metal casing c. Asbestos
or other non-conductor of heat is inserted between the said walls and the metal
casing, as at d. The vessel a is supported upon a bed e of fire-brick having
transverse passages el, at suitable intervals, for the admission of air to support
combustion. These passages extend alternately on either side of the furnace to the
exterior thereof, and are provided with suitable doors f, whereby the supply of air
can be regulated.
g is a flue or passage extending through or beneath the bed e, into which flue the
air and gas are admitted as hereinafter described. h, h are flues or passages formed
between the pan or vessel a and the walls b for the purpose of retarding the
passage of the heat through the furnace and conducting it several times around
the said pan or vessel before permitting it to escape from the furnace through tho
chimney i
is a pipe for the supply of gas to the furnace. This pipe extends into a large
tube 4, into which air is admitted, through the pipe m, so that it will mix with
the gas. The air and gas, before entering the furnace, are caused to pass through

page_text: one or more sheets n¹ of wire-gauze stretched across a chamber n, in order to
thoroughly mix them. They then pass from the part of the pipe l.into the flue
or passage g. The pipe k is provided at ¹ with a suitable stop-cock, and a small
pipe o is connected with the pipe at. The pipe o extends into the flue or
passage g, in front of the inlet for the gas arid air, and the said pipe is provided
with a stop-cock at o¹. A small quantity of gas is allowed to pass through the
pipe o, and issues therefrom in a small jet, which, when lighted, serves for igniting
the mixture of air and gas entering from the tube 1. The pipe o can, if desired, be
tipped with platinum or other metal which fuses at a very high temperature.
It will bo seen that the gas issuing from this pipe can, if desired, be kept burning
when the cock at ¹ is closed, so that, immediately this cock is opened, the mixture
of gas and air will be ignited.
The furnace above described may be entirely closed in, so. that no vapours can
escape therefrom except through the chimney i.
In some cases it may be desirable for a manufacturer to make the gas necessary
for heating the furnace, if he can make use of the ammonia, tar, coke, and other
residual products.
The following are some of the advantages afforded by our invention over furnaces
which are heated by coal or coke for the purposes specified, viz:-The heat can be
kept uniform, and the excessive accumulation of dross thus prevented; the necessity
of frequently cleaning the furnaces is obviated; the pans or baths can be made of
thinner metal than when designed to be heated by coal or coke; and, the furnace
being entirely closed, no sulphurous vapours can escape therefrom among the
work-people and cause injury to health.
•
We wish it understood that we do not limit ourselves, in the application of our
invention, to the use of the special means above described for admitting the mixture
of air and gas in the required volume, as it is obvious that we can, if desired,
use other means for this purpose. Nor do we confine ourselves to any particular
arrangement of the flues or passages in the furnace. It is obvious, moreover,
that our apparatus may, if desired, be used for melting other metals than tin
and spelter.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed we declare that what
we claim is
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•
First. The combination, with a furnace for melting tin, spelter or similar metals,
of means whereby air and gas can be intimately mixed and admitted into the said
furnace in a considerable volume, as, and for the purposes, above specified.
Second. The improved apparatus consisting of the furnace and other parts con-
structed and combined substantially as described with reference to the accompanying
drawing, for the purposes above specified.
HASELTINE, LAKE & Co.,
For the Applicants.