Improvements in Annealing Furnaces.
Year: 1891

page_text: Date of Application, 7th Aug., 1891
Complete Specification Left, 3rd June, 1892-Accepted, 9th July, 1892
PROVISIONAL SPECIFICATION.
Improvements in Annealing Furnaces.
We, HOWARD LANE of Corporation Street Birmingham Consulting Engineer
& ARTHUR CHAMBERLAIN of No. 4 New Bartholomew Street Birmingham
Manufacturer, do hereby declare the nature of this invention to be as follows:-
Our improved furnace is more particularly suited to the annealing of metal
articles of an elongated form, & has for its object the more perfect & more uniform
annealing of such articles, combined with the non-formation of scale. It consists of
a muflle of a generally cylindrical figure placed horizontally & capable of rotation;
the ends are open & loosely fit on the circular mouths of flues or passages having
valves or openings for the admission of gas & air and the insertion of the articles
to be annealed. The valves are so arranged that the gaseous fuel with air to
support combustion can be admitted alternately at either end of the muffle, the
products of combustion escaping at the opposite end at a certain point in the
operation the supply of air may be reduced with a view to prevent the formation of
scale. In some cases we add chambers for heating the gas or air or both on the
regenerating principle. During the operation of heating the articles the cylinder is
slowly rotated by means of rollers on which it rests. We provide means for
preventing the loosely fitting joints at the two ends of the cylinder being altered by
the expansion of the cylinder.
Dated this Fifth day of August. 1891
HOWARD LANE.
ARTHUR CHAMBERLAIN.
COMPLETE SPECIFICATION.
Improvements in Annealing Furnaces.
We, HOWARD LANE of Corporation' Street, Birmingham Consulting Engineer
and ARTHUR CHAMBERLAIN of No. 4 New Bartholomew Street Birmingham
Manufacturer do hereby declare the nature of our invention and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement :-
Our improved furnace is more particularly suited to the annealing of metal
articles of an elongated form and has for its object the more perfect and more
uniform annealing of such articles combined with the non-formation of scale.
It consists of a muffle of a generally cylindrical figure placed horizontally and
capable of rotation. The ends are open and loosely fit on the circular mouths of
flues or passages having valves or openings for the admission of gas and air and the
insertion of the articles to be annealed. The valves are so arranged that the
gaseous fuel, with air to support combustion, can be admitted alternately at either
end of the muffle the products of combustion escaping at the opposite end at a
certain point in the operation the supply of air may be reduced with a view to
prevent the formation of scale. In some cases we add chambers for heating the
gas or air or both on the regenerative principle. During the whole of the operation
of heating the articles, the cylinder is slowly rotated by means of rollers on which
it rests or by gearing. We provide means for preventing the loosely fitting
joints at the two ends of the cylinder being altered by the expansion of the
cylinder.

page_text: We will now proceed to describe with reference to the accompanying drawings
the manner in which our invention is to be performed.
Figure 1 represents in longitudinal vertical section; Figure 2 in plan, with the
annealing muffle omitted and Figure 3 in end elevation, an annealing furnace
constructed according to our invention, in conjunction with regenerative chambers
heated by the waste lieat from the said muffle the said regenerative chambers being
used for heating the air which is supplied to the gaseous fuel by which the muttle is
heated;
Figure 4 represents a cross section of the muffle and regenerative chambers taken
through one of the end caps of the muffle;
Figure 5 represents a cross section taken through the muffle and
Figure 6 represents in section one of the pipes by which atmospheric air is
conducted to the regenerative chamber to be heated by it or the waste heat
conveyed from the muffle to the chimney flue.
The same letters of reference indicate the same parts in the several figures of the
drawings.
a is the rotary cylindrical annealing muffle open at its ends and lined with fire
clay or other refractory material, in which muffle the tubes, strips or elongated or
other metallic articles to be annealed are packed or placed. The open ends of the
muffle bear against the open mouths of the end caps or chambers, beach cap
being provided with a loose fitting joint and carried by the pair of adjustable
trunnion rods c, e the lower ends of which turn upon trunnions at opposite sides of
the cap and their upper ends are jointed to a cross bar at the end of the muffle (sec
Figure 3). By thus supporting the caps, provision is made for the expansion
and contraction of the muffle and caps by changes of temperature without interfering
with the efficiency of the joints. It will be seen by an examination of Figure I
that each end of the muffle has a conical flange which bears against the inclined
bearing seat at at the mouth of the cap. The articles to be annealed are
introduced into and removed from the muffle a by removing the covers d, d on the
caps b, which covers are fixed in their places by jointed cross bars and screws
affer the manner in which the covers of gas retorts are fastened. The rotary
cylindrical muffle is supported by and turns on the pairs of anti-friction rollers ee: ee
at the middle and ends of the muffle. The supporting rollers at the middle of the
muffle are shown in Figure 5 and the supporting rollers at the end of the muffle in
Figure 3. A slow rotary motion is given to the muffle a by the worm wheel at its
middle with which the worm g gears (see Figure 5) the said worm being driven by
hand or by steam or other motive power.
Beneath the rotary muffle a are two parallel regenerative chambers marked
respectively and i for heating the air to he supplied to the gaseous fuel by which
the muffle is heated. The said regenerative chambers h, i are provided with
connections of the kinds hereinafter described whereby either chamber can be put
into communication with either end of the muffle for receiving the waste heat and
products of combustion from the said muffle, one of the said chambers being used
for heating atmospheric air while the other chamber is being heated. Under the
middle of the annealing muffle a. is a main cross flue & into which gaseous fuel, such
for example as carbonic oxide from a generator, is supplied to be conveyed to either
end of the muffle, which gaseous fuel coming in contact with heated air supplied to it
as hereinafter described burns as is well understood and heats the rotary muffle,
the flame and heated air being drawn through the muffle in the manner hereinafter
described.
In order to supply gaseous fuel and heated air to either end of the muffle and to
connect one of the regenerative chambers h or with one or other end of the muffle
and at the same time to connect that regenerative chamber receiving waste heat
from the muffle, with the chimney flue, we arrange the connections and valves at
the ends of the muffle in the following manner. At the right hand end of the
muffe are three pipes marked respectively l, m, n. The pipe is used either for
supplying atmospheric air to the regenerative chamber to be heated by the said

page_text: chamber or for connecting the regenerative chamber while being heated by the
waste heat from the muffle, with the chimney flue p. The said pipe is furnished
with a valve for opening it to and shutting it from the atmospheric air.
The pipe m is the gas supply pipe and opens into the right hand cap of the
muffle and into the main gas supply flue . The said pipe m is provided with a
valve m³ for opening and closing the said pipe (see the left hand end of the muffle).
The third pipe is the pipe by which the heated air from the regenerative
chamber is supplied to and mixed with the gaseous fuel conveyed by the
pipe m to the cap at the right hand end of the muffle. The pipe n has no valve
in it and also serves to connect the regenerative chamber being heated with the
muffle.
72
The pipes 12, m, n² at the left hand end of the muffle are for the purpose of
supplying the gas and heated air to the left hand cap of the muffle and for putting
that end of the muffe in connection with the regenerative chamber i, when the
direction of the current of heated air and products of combustion through the muffle
is changed that is to say, the valved pipe 2 connects the chamber being heated
with the chimney flue q; the valved pipe m² supplies gas to the left hand cap of the
muffle and the pipe n supplies heated air from the regenerative chamber to the
left hand cap of the muffle, and also connects the regenerative chamber / being
heated with the muffle.
The action of the parts is as follows:-
Supposing the current of heated air is passing through the rotary muffle a in the
direction indicated by the arrows in the said miffle Figure 1, the connections are
arranged in the following manner. The regenerative chamber h, which has been.
heated, is supplied with air from the pipe the valve in which has been opened to
the atmosphere. By the circulation of air through the said regenerative chamber h,
it is heated and supplied by the pipe n to the right hand cap 5 of the muffle. The
valve of the pipe m being opened and the valve in the other pipe m² being closed
gas is supplied from the main gas flue k through the said pipe m to the right hand
cap to be mixed with the heated air supplied to the last named cap by the
pipe The valve in the pipe is closed to the atmosphere and the waste heat
issuing from the left hand end of the muffle is conveyed through the pipe n² into
the regenerative chamber by which it is heated, the said chamber being
connected with the chimney flue p by the pipe 1, the valve of which is closed to the
atmosphere.
n.
In order to reverse the direction of the current through the muffie and supply gas
and heated air to the left hand cap of the muffle and put the said muffle in
connection with the regenerative chamber h, when cold, the valve 13 in the pipe / is
opened to the atmosphere and the valve in the pipe is reversed. The valve m³ in
the gas pipe m is closed and the valve in the gas pipe m³ is opened. Gas and
heated air are now supplied to the left hand cap of the muffle by the pipes m³
and n² and the waste heat from the muffle passes by the pipe n to the regenerative
chamber for heating the same, the said chamber being in communication by the
pipe with the chimney flue 4. In this way the gaseous fuel and heated air can be
supplied to either end of the muffle and one or other of the regenerative chambers
be heated by the waste heat issuing from either end of the muffle.
In starting the apparatus all the parts being cold, it is necessary to ignite the
mixture of gas and air in the cap by a flame introduced into the said cap through a
hole in it capable of being closed after the gaseous mixture has been ignited.
When it is desirable to heat the inflammable gas as well as the air, additional
regenerative chambers may be employed for that purpose.
Having now particularly described and ascertained the nature of our invention
and the manner in which the same is to be performed we declare that we claim.
as our invention of "Improvements in annealing furnaces":
First The combination of a slowly rotating muffle, constructed substantially as
hereinbefore described and illustrated, with loosely fitting end closing caps so

page_text: supported with respect to the open ends of the muffle that the expansion and
contraction of the said muffle and caps do not impair the efficiency of the joints of
the said muffle and caps as herein before described and illustrated in the accom-
panying drawings.
Secondly The combination with a slowly rotating muffle of the kind referred
to in the preceding claim of regenerative chambers heated by the waste heat and
products of combustion from the said muffle, the said regenerative chambers being
used for heating the air or gas or both to be supplied to the muffle for heating the
same substantially as hereinbefore described and illustrated in the accompanying
drawings.
Thirdly The arrangement or combination of the parts herein before described
and illustrated in the accompanying drawings for admitting the gaseous fuel and
heated air at either end of the muffle and for changing the direction of the waste
heat from the muffle and the air or gas to be heated through the regenerative
chambers.
Dated the Second day of June 1892
W. T. WHITEMAN,
Agent for the Applicants.