Improvements in Furnaces.
Year: 1893

page_text: Date of Application, 3rd Feb., 1893-Accepted, 18th Mar., 1898
COBLEMELE DE BORRATIVA
Improvements in Furnaces.
We JAMES ASHTON FLETCHER and SAMUEL FLETCHER both of Borough
Brass Works, Ashton-under-Lyne, in the County of Lancaster, Brass Founders,
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:
Our said invention relatos to improvements in furnaces such as are. used by brass
founders and others for melting metals in crucibles aud is more particularly
applicable to that type of furnace in which the part of the furnace which holds the
crucible is surrounded by an annular space for the purpose of heating the air before
it reaches the burning fuel.
The objects of our said invention are to render such furnaces equally convenient
for use either when employing an induced draught through the fuel or when a
forced draught as from a fan or blower is employed and also to provide means for
more readily cleaning out slag, ashes and dross from the interior of the furnace.
A furnace constructed in accordance with our said invention is shown in the
accompanying drawings of which Fig. 2 is a plan and Fig. 1 is a sectional elevation
the left hand half of which is taken at an angle to the right hand half as for
example through a y of Fig. 2.
In this drawing the crucible a and its supporting block a¹ are indicated by dotted
lines. Between the supporting block and the crucible and surrounding the latter is
placed the fuel. bis the refractory lining of the furnace carried in the inner shell 6'
between which and the outer shell d is an annular air space a communicating by means
of several orifices e with the interior of an aunular air supply belt by which the
air is admitted and distributed around the inner shell. By this means the
temperature of the air is raised before it reaches the combustion zone in the interior
of the farance. g is the outlet for the products of combustion. At suitable places
round the air supply belt as for example at h and also at the bottom of the furnace
at we provide hinged doors giving access to the interior of the air supply belt ƒ
and the bottom of the furnace respectively.
The said doors are inclined towards the furnace and are set at such an angle and
are made of such a weight as that the apertures against which they rest shall
remain closed when a forced draught is used so long as the air pressure does not
exceed a certain predetermined point. Should the air pressure however become
too great the hinged doors will lift and thus act as safety valves for the excessive
pressure.
The lower doors provide means for readily removing slag, dross, ashes and the
like from the bottom of the furnace.
The furnace is provided at the bottom with a hinged cover and has the usual
cap or covering plate at the top. m m are the feet or supports on which the
furnace rests.
The
upper part of the furnace is preferably detachable and is secured to the lower
part by lugs and bolts o as will be well understood without further description.
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―
I. In a melting furnace having an annular air belt and air jacket for heating the
entering air the use in combination therewith of apertures covered by hinged doors
so set and weighted as to remain set open when using induced draught and to close
the said apertures when placed in position for using forced draught while acting as

page_text: safety valves for the escape of the excess pressure when using forced draught
substantially as and for the purpose hereinbefore set forth and shown in the accom-
panying drawings.
II. In a furnaco of the kind hereinbefore described the use of an annular air
jacket having one or more aportures through the outer shell thereof giving access to
the bottom of the furnace for facilitating the removal of dross slag ashes or the
like substantially as and for the purpose hereinbefore described and shown in the
accompanying drawings.
Dated this 31st day of January 1893.
EDWARD TURNER WHITELOW,
70, Deansgate, Manchester, Agent for the Applicants.