Improvements in Gas Furnaces.
Year: 1897

page_text: Date of Application, 18th Mar., 1897-Accepted, 5th June, 1897
Improvements in Gas Furnaces.
We, THOMAS FLETCHER and FLETCHER, RUSSELL & Co. LIMITED both of
Thynne Street Warrington in the County of Lancaster, Manufacturers of Gas
Apparatus, 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 those gas furnaces used by metallurgists, enamellers,.
dentists, chemists, jewellers, glass painters and others, in which gaseous fuel mixed:
with air under pressure is employed. In such blast-burner and blow-pipe furnaces
it has hitherto been found difficult or impossible to work with certain materials, or
to obtain certain results owing to inherent defects either in the construction of the
apparatus, the method of its use, the composition of the gaseous fuel, and other
causes which it is the object of this invention to remove or avoid.
In carrying out our invention, we employ a gaseous fuel composed of air under
pressure charged with a light liquid hydrocarbon such as gasolene or benzolene,
the proportions varying according to known laws and being, for the production of
an oxidising flame, a mixture of air less than saturated with the hydrocarbon, and
for a reducing flame, air fully saturated or supersaturated with the hydrocarbon.
The air may be forced under pressure through the light liquid bydrocarbon, and is
delivered to the furnace through blow-pipes or blast-burners of suitable construction.
such for example as those at present in use with such furnaces. The flame and
beat produced in the furnace have, under the specified conditions, no action of an
injurious character upon the most delicate enamels, glass painters' and stainers"
colours, lead glass and the like, and thus muffles and other equivalent costly
appliances and arrangements may be dispensed with. These facts make our
invention especially applicable for furnaces used by glass painters, enamellers, for
delicate chemical operations, for glory holes for glass blowers and glass workers,.
and the like. The use of a drip or an excess of the light liquid hydrocarbon
hereinbefore referred to as producing saturation or supersaturation of the air when
a reducing heat is required, results, according to our invention, in the dis-
continuance of the use of saggers, closed chambers, and boxes, inside the furnaces
when employed for heating steel, for hardening, annealing and other similar.
processes.
We may employ any suitable construction of furnace, but we usually arrange-
that the flame shall, as in a reverberatory furnace, be directed upon the articles to
be heated therein. Thus, in a cylindrical furnace, such as those in which crucibles.
are beated, instead of directing the flame radially into the furnace, we direct it, by
preference, tangentially. In this case the flame sweeps around the article in the
furnace and every part of it is equally heated, whilst in the ordinary furnace the
side next to the flame is first heated and always is heated to a higher temperature-
than the remainder. Similarly, in large furnaces, a ring of fireclay, magnesia, or
other suitable fire resisting material may be arranged on the floor of the furnace
and the flame be injected at a tangent to the inner circumference of the ring within.
which the articles to be heated are exposed. The mixed air and hydrocarbon may
however be injected into the furnace otherwise, as for example from the top.
downwards. The temperature may be regulated by varying the air pressure.

page_text: Instead of blowing the air under pressure through the light liquid hydrocarbon
as herein before described, we may, for the like purpose, cause it to pass over
surfaces composed of or charged with the hydrocarbon.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what
we claim is :-
1. In blast-burner and blow-pipe furnaces, injecting air under pressure in which
a sufficiency of a light liquid hydrocarbon is suspended, in such a manner that the
inflamed mixture comes into direct contact with and heats as uniformly as possible
the articles exposed therein thus doing away with the necessity for muffles
and other protectors; substantially as and by the means herein before described.
2. In blast-burner and blow-pipe furnaces, in which an inflamed mixture of a
light hydrocarbon and air under pressure are employed, injecting the mixed air and
hydrocarbon at a tangent to the inner diameter of a ring or cylinder enclosing the
articles to be heated.
Dead thin 17th In L AD 1007
W. E. HEYS & SON,
Agents for the Applicants.