Improvements in Metallurgical Furnaces.
Year: 1893

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Date of Application, 24th Oct., 1893
Complete Specification Left, 24th July, 1894-Accepted, 25th Aug., 1894
PROVISIONAL SPECIFICATION.
[Communicated from abroad by George FrederICK SIMONDS, of Fitchburg,
in the County of Worcester, State of Massachusetts, United States of
America, Engineer.]
Improvements in Metallurgical Furnaces.
1, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby declare
the nature of this invention to be as follows :-
This invention relates to furnaces for tempering or annealing and for performing
other operations requiring a working chamber or oven that can be uniformly
heated throughout and "in which the desired uniform temperature can be
inaintained.
The important feature of the present invention is the provision of a furnace
having a working chamber surrounded by a heating chamber and an intermediate
closed dead air-space, preferably in the form of a tortuous passage, in contact with
substantially all sides of the working chamber and with which a fan communicates
for the purpose of causing a constant circulation of heated air throughout said
intermediate closed space or tortuous passage and thereby maintaining a uniform
temperature in all parts of the working chamber. The said invention comprises
the features of construction and novel combinations of parts in a tempering or
annealing furnace as hereinafter set forth.
According to this invention, the furnace in its preferred form is constructed
with non-conducting inner and outer walls of fire brick, preferably having a dead
air-space or spaces between the inner and outer walls, and a coating or filling of
cement or other suitable non-conducting material inclosed in the outer walls.
In the upper part of the combustion chamber are brackets supporting a
horizontal diaphragm which forms the floor of a heating chamber that constitutes
the upper part of the furnace. The said diaphragm does not extend to the walls
of the furnace but is so arranged as to leave flues at the front and rear and on both
sides thereof, for the upward passage of the products of combustion into the heating
chamber. On each side, the heating chamber communicates, through an opening,
with flues built in the furnace walls and connecting with an exit flue at the rear.
The beating chamber contains a working chamber constructed with double walls
between which several series of dead air-spaces are inclosed. These air-spaces
communicate with each other, and with a rotary fan that is arranged in an enlarged
portion of one of said spaces. The fan is provided with a shaft extended to the
outside of the furnace and having a pulley thereon through which the fan can be
rotated for the purpose of causing a continuous circulation of the heated air
inclosed in the communicating dead air-spaces and thereby equalizing the
temperature of all parts of the working chamber.
I prefer to construct the working chamber in the form of two metallic shells or
boxes, one arranged or nested within the other. These shells or boxes may each
have a rectangular form to correspond with the substantially rectangular interior
of the heating chamber in which the said working chamber is placed. The outside
of the inner box or shell, forming the inner wall of the working chamber, is
provided with flanges or ribbed projections of varying length and disposed on all
sides in such directions and at such intervals as to form with the smooth interior
of the outer box, shell or wall several series of communicating spaces that thus
constitute a tortuous passage for the inclosed heated air circulated by the fan

page_text: aforesaid in contact with all parts of the surface of the working chamber. It will
be understood that the heated air thus circulated in the tortuous passage or
communicating air spaces between the double walls of the working chamber is
wholly confined to said spaces, and has no inlet or outlet and no communication
with the atmosphere nor with any part of the furnace. The rotary fan for causing
a continuous circulation of heated air in the said communicating spaces is preferably
located in one of the rear upper corners of the outer box or shell, the said outer
box or shell being slightly enlarged at that point to form a fan casing. One of the
flanges or ribs of the inner box or shell is cut away for the purpose of forming a
draught opening in which the fan is received when the inner and outer shells are
brought together.
The outer box or shell forming the outer wall of the working chamber, may be
provided on its outside with encircling flanges or ribbed projections, forming
separate passages which communicate directly at all points with the heating
chamber and thus serve to assist in equalizing the distribution of heated products
of combustion in contact with all parts of the outer wall of the working chamber.
By thus providing for a somewhat equalized distribution of the heated products
of combustion passing through the heating chamber, the heat is economized and
the confined air in the dead air-space or tortuous passages between the walls of the
working chamber will be more quickly heated. The continuous circulation of this
heated air through the closed tortuous passages or spaces in contact with all parts
of the working chamber, by the action of the fan, permits the maintenance
throughout said chamber of a steady and uniform temperature which is so essential
in order to obtain satisfactory results in tempering or annealing and other
operations in which a perfectly uniform heat is desirable.
The working chamber is provided with a tightly closing door of any suitable
non-conducting construction.
Jatahan 1402
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Metallurgical Furnaces.
1. HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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 furnaces for tempering or annealing and for performing
other operations requiring a working chamber or oven that can be uniformly heated
throughout and in which the desired uniform temperature can be maintained.
The important feature of the present invention is the provision of a furnace
having a working chamber surrounded by a heating chamber and an intermediate
closed dead air-space, preferably in the form of a tortuous passage, in contact with
substantially all sides of the working chamber and with which a fan communicates
for the purpose of causing a constant circulation of heated air throughout said
intermediate closed space or tortuous passage and thereby maintaining a uniform
temperature in all parts of the working chamber. The said invention comprises
the features of construction and novel combinations of parts in a tempering or
annealing furnace as hereinafter set forth.
In order that the invention may be clearly understood I will now proceed to
describe the same with reference to the accompanying drawings in which,
Figure 1 is a sectional side elevation of my improved furnace with portions of
the inner and outer walls of the working chamber broken away.

page_text: 2-ས་་
working chamber.
UVA UL CALLS T
Figure 3 is a similar view of the box or shell forming the outer wall of the
working chamber.
Figure 4 is a horizontal section of one corner of the working chamber and
surrounding dead air spaces or passage.
Referring to Figure 1, the numeral 1 designates the ash-pit; 2 the grate and 3
the combustion chamber. The furnace is constructed with non-conducting inner
and outer walls of fire brick 4, preferably having a dead air space or spaces 5.
between the inner and outer walls and a coating or filling 6 of cement or other
suitable non-conducting material inclosed in the outer walls.
In the upper part of the combustion chamber 3 are brackets 7 supporting
horizontal diaphragm 8. which forms the floor of a heating chamber 9 that
constitutes the upper part of the furnace. The diaphragm 8 does not extend to the
walls of the furnace but is so arranged as to leave flues 10 at the front and rear
and on both sides thereof for the upward passage of the products of combustion into
the heating chamber. On each side, the heating chamber communicates, through
an opening 11, with flues 12 built in the furnace walls and connecting with an exit
flue 13 at the rear.
The heating chamber 9 contains a working chamber 14 constructed with double
walls between which several series of dead air spaces 15 are inclosed. These air
spaces 15 communicate with each other and with a rotary fan 16 that is arranged
in an enlarged portion 17 of one of said spaces. The fan 16 is provided with a
shaft 18 mounted in suitable bearings and extended to the outside of the furnace,
and having a pulley 19 thereon through which the fan can be rotated for the
purpose of causing a continuous circulation of the heated air inclosed in the
communicating spaces 15 and thereby equalizing the temperature of all parts of
the working chamber.
I prefer to construct the working chamber 14 in the form of two metallic shells
or boxes, as 20, Figure 2, and 21, Figure 3, one arranged or nested within the
other, as shown in Figure 1. These shells or boxes 20 and 21 may each have a
rectangular form to correspond with the substantially rectangular interior of the
heating chamber 9 in which the working chamber 14 is placed. The outside of the
inner box or shell 2", forming the inner wall of the working chamber, is provided
with flanges or ribbed projectious 22 of varying length and disposed on all sides in
Buch directions and at such intervals as to form with the smooth interior of the
outer box, shell or wall 21 several series of communicating spaces 15 that thus
constitute a tortuous passage for the inclosed heated air circulated by the fan 16
in contact with all parts of the surface of the working chamber, as indicated by the
arrows in Figures 1 and 2. It will be understood that the heated air thus
circulated in the tortuous passage or communicating air spaces 15 between the
double walls of the working chamber is wholly confined to said spaces and has no
inlet or outlet and no communication with the atmosphere nor with any part of the
furnace. The rotary fan 16 for causing a continuous circulation of heated air in
the communicating spaces 15 is preferably located in one of the rear upper corners
of the outer box or shell 21, the said outer box or shell being slightly enlarged at
that point to form a fan casing 17 as shown in Figures 3 and 4. One of the flanges
or ribs 22 of the inner box or shell 20 is cut away at 23, Figure 2, for the purpose
of forming a draught opening in which the fan 16 is received when the inner and
outer shells are brought together.
The outer box or shell 21, forming the outer wall of the working chamber, may
be provided on its outside, as shown in Figure 3, with encircling flanges or ribbed
projections 24, forming separate passages 25 which communicate directly at all
points with the heating chamber 9 and thus serve to assist in equalizing the
distribution of heated products of combustion in contact with all parts of the outer
wall of the working chamber. By thus providing for a somewhat equalized
distribution of the heated products of combustion passing through the heating

page_text: chamber 9 the heat is economized and the confined air in the space or tortuous
passages 15 between the walls of the working chamber will be more quickly heated.
The continuous circulation of this heated air through the closed tortuous passages
or spaces 15 in contact with all parts of the working chamber, by the action of the
fan 16 permits the maintenance throughout said chamber of a steady and uniform
temperature which is so essential in order to obtain satisfactory results in tempering
or annealing and other operations in which a perfectly uniform heat is desirable.
As shown in Figure 1, the working chamber 14 is provided with a tightly closing
door 26 constructed of any suitable non-conducting material.
•
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
--
1. In a furnace, the combination with a working chamber having double walls
between which a dead air-space is inclosed, of a rotary fan located in said dead air
space for the purpose of causing a continuous circulation of heated air therein to
equalize the temperature of the working chamber, substantially as described.
2. In a furnace, the combination with a working chamber, and dead air-spaces
surrounding said chamber and communicating with each other to form a tortuous
passage for heated air, of a fan communicating with said spaces or tortuous passages
for the purpose of causing a continuous circulation of heated air therein to equalize
the temperature of the working chamber, substantially as described.
3. In a furnace, the combination of a combustion chamber, a heating chamber
communicating with the combustion chamber, a working chamber located in the
heating chamber and provided with double walls between which a closed dead air-
space is inclosed, and a fan communicating with said dead air-space and adapted to
cause a continuous circulation of heated "air therein for the purpose of equalizing
the temperature of the working chamber, substantially as described.
4. A furnace constructed substantially as herein described for the purpose
specified.
Pattu COIS EG
ΟΙ
1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.