IMPROVE- MENTS IN FURNACES FOR HEATING AND MELTING METALS AND METALLIC. ALLOYS
Year: 1872

page_text: LETTERS PATENT to Charles Walker Torr, of Aston, near Birmingham,
in the County of Warwick, Manager of Works, and John Johnstone,.
of Birmingham, aforesaid, Chemist, for the Invention of "IMPROVE-
MENTS IN FURNACES FOR HEATING AND MELTING METALS AND METALLIC.
ALLOYS."
Sealed the 21st February 1873, and dated the 5th September 1872.
PROVISIONAL SPECIFICATION left by the said Charles Walker Torr
and John Johnstone at the Office of the Commissioners of Patents,
with their Petition, on the 5th September 1872.
We, CHARLES WALKER TORR, of Aston, near Birmingham, in the
County of Warwick, Manager of Works, and JOHN JOHNSTONE, of
Birmingham, aforesaid, Chemist, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN FURNACES FOR HEATING AND MELTING
METALS AND METALLIC ALLOYS," to be as follows:-
Our Invention consists of the improvements herein-after described in
constructing and arranging the parts of furnaces for heating and melting
metals and metallic alloys.

page_text: We will describe our Invention in connection with a furnace for
melting brass, for casting ingots, or for other like purposes.
The fire-place consists of a series of bars of the ordinary kind supported
over an ash-pit, provided with a door which may be open to any required
extent, or closed at pleasure. Over the fire-bars is a hopper, into the
top of which the fuel is fed, the said fuel gradually descending as the
lower part of the column of fuel supported on the fire-bars is burned
away. Only so much air is admitted to the fuel in the fire-place as is
necessary to keep up combustion therein for the generation of gaseous
fuel to be afterwards burned. The gaseous fuel from the fire-place
passes by a nearly horizontal flue or channel into the lower part of a
chamber, on the bottom of which the crucible or crucibles, or melting
pots stand. In the said flue, and at a short distance from the fire-place,
and by preference in the upper side of the flue is a slit or opening
through which heated air is supplied to the gaseous fuel passing from
the fire-place to the crucible chamber. The air supplied to the slit or
opening is heated by the waste heat of the stack, or is heated in any
other convenient manner. The mixture of heated air and gaseous fuel
enters into a state of active combustion in the crucible chamber, and the
crucible standing therein is completely enveloped in flame. Near the
upper part of the crucible chamber is a horizontal slit or opening through
which the products of combustion pass to the chimney or stack. The
tops of the fuel hopper and the crucible chamber are closed by removeable
covers so as to prevent the entrance of external air into the said fuel
hopper and crucible chamber at the tops of the same. The tops of the
fuel hopper and crucible chamber are by preference on the same level,
and at a short distance above the ground level, while the fire-place and
ash-pit are at a considerable distance below the ground level.
The draught of air through the furnace is regulated by the ash-pit
door, by a valve or damper in the chimney or stack, and when necessary
by a valve or damper in the flue, which supplies hot air to the gaseous
fuel passing to the crucible chamber.
Where we apply our Invention to furnaces other than furnaces of the
kind described, we preserve the same general construction and arrange-
ment of parts, but in place of the crucible chamber described we
substitute a chamber of the construction necessary to the particular use
to which the furnace is to be applied. For example, where the furnace

page_text: is to be used for heating metals or metallic articles for the purpose of
annealing the same, we substitute in place of the crucible chamber
herein-before described, a muffle of of the kind ordinarily employed in
annealing metals, and where the furnace is to be used for heating
metallic tubes for brazing the same, we substitute for the crucible
chamber a horizontal tubular chamber of the ordinary kind.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles Walker Torr and John Johnstone in the
Great Seal Patent Office on the 4th March 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, CHARLES
WALKER TORR, of Aston, near Birmingham, in the County of Warwick,
Manager of Works, and JOHN JOHNSTONE, of Birmingham, aforesaid,
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of September, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said Charles Walker Torr and John Johnstone,
Her special license that we, the said Charles Walker Torr and John
Johnstone, our executors, administrators, and assigns, or such others
as we, the said Charles Walker Torr and John Johnstone, our exe-
cutors, administrators, and assigns, should at any time agree with, and
no others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN FURNACES FOR HEATING AND MELTING METALS AND METALLIC ALLOYS," upon
the condition (amongst others) that we, the said Charles Walker
Torr and John Johnstone, our executors or administrators, by an instru-
ment in writing under our, or their hands and seals, or under the hand
and seals of one of us or them, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.

page_text: NOW KNOW YE, that we, the said Charles Walker Torr and John
Johnstone, do hereby declare the nature of the said Invention, and
in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement thereof,
that is to say :-
Our Invention consists of the improvements herein-after described
in constructing and arranging the parts of furnaces for heating and
melting metals and metallic alloys.
We will describe our Invention in connection with a furnace for
melting brass, for casting ingots, or for other like purposes.
The fire-place consists of a series of bars of the ordinary kind
supported over an ash-pit provided with a door which may be opened
to any required extent or closed at pleasure. Over the fire-bars is a
hopper into the top of which the fuel is fed, the said fuel gradually
descending as the lower part of the column of fuel supported on the
fire-bars is burned away. Only so much air is admitted to the fuel in
the fire-place as is necessary to keep up combustion therein for the
generation of gaseous fuel to be afterwards burned. The gaseous fuel
from the fire-place passes by a nearly horizontal flue or channel into
the lower part of a chamber, on the bottom of which the crucible
or crucibles, or melting pots stand. In the said flue and at a short
distance from the fire-place, and by preference in the upper side of
the flue, is a slit or opening through which heated air is supplied to
the gaseous fuel passing from the fire-place to the crucible chamber.
The air supplied to the slit or opening is heated by the waste heat
passing to the stack, or is heated in any other convenient manner.
The mixture of heated air and gaseous fuel enters into a state of active
combustion in the crucible chamber, and the crucible standing therein
is completely enveloped in flame. Near the upper part of the crucible
chamber is a horizontal slit or opening through which the products of
combustion pass to the chimney or stack. The tops of the fuel hopper
and the crucible chamber are closed by removable covers so as prevent
the entrance of external air into the said fuel hopper and crucible
chamber at the tops of the same. The tops of the fuel hopper and
crucible chamber are by preference on the same level and at a short
distance above the ground level, while the fire-place and ash-pit are
at a considerable distance below the ground level.

page_text: The draught of air through the furnace is regulated by the ash-pit
door, by a valve or damper in the chimney or stack, and when necessary
by a valve or damper in the flue, which supplies hot air to the gaseous
fuel passing to the crucible chamber.
Where we apply our Invention to furnaces other than furnaces of the
kind described, we preserve the same general construction and arrange-
ment of parts, but in place of the crucible chamber described we
substitute a chamber of the construction necessary to the particular use
to which the furnace is to be applied. For example, where the furnace
is to be used for heating metals or metallic articles for the purpose
of annealing the same, we substitute in place of the crucible chamber
herein-before described a muffle of the kind ordinarily employed in
annealing metals, and where the furnace is to be used for heating
metallic tubes for brazing the same we substitute for the crucible
chamber a horizontal tubular chamber of the ordinary kind.
Having explained the nature of our Invention, we will proceed to
describe with reference to the accompanying Drawings the manner in
which the same is to be performed.
Figure 1 represents in vertical section a compound furnace constructed
according to our Invention, for melting metals; Figure 2 is a plan
(partly in section) of one half of the furnace; and Figure 3 is a
horizontal section of the said furnace, the halves being taken at different
levels. The section, Figure 1, is taken through the line A, B, of Figure 3;
the upper half of the horizontal section of the furnace Figure 3 is taken
on the line C, D, of Figure 1; and the lower half of the said horizontal
section Figure 3 is taken on the line E, F, of Figure 1.
The same
letters of reference indicate the same parts in Figures 1, 2, and 3.
a, a, are the fire-places; b, b, are the hoppers over the said fire-places,
for supplying fuel thereto; c, c, are the ash-pits; and d, d, are vertical
chambers near the bottoms of which the crucibles or melting pots e, e,
containing the metal or alloy to be melted rest. Below the ground
level and around the compound furnace is a passage or covered way f,
by which access to the fire-places a, a, is gained, the tops of the
hoppers b, b, and crucible chambers d, d, being situated nearly on a
level with the ground line. The covers of the hoppers b, b, and crucible
chambers d, d, are not represented in the Drawing, but when the
furnace is at work the said hoppers and chambers are closed to prevent

page_text: the entrance of external air. The gaseous fuel generated by the partial
combustion of the solid fuel in each of the fire-places a, a, passes by the
flue or channel g into the lower part of the crucible chamber d, the said
gaseous fuel on its way to the said chamber d being mixed with hot air
supplied by the slit or opening h. The mixture of heated air and
gaseous fuel enters into a state of active combustion in the crucible
chamber d and heats the crucibles therein. The heated air and products
of combustion pass out of the crucible chamber d at the slit i (see
Figure 1) near the upper part of the said chamber. They then descend
the flue or passage k, k³, and escape by the stack or chimney l.
The heated air which is mixed with the gaseous fuel on its way to the
crucible chambers d, d, is heated by the waste heat from the said
chambers in the following manner:-Between the horizontal parts k³
of the flues which open into the stack are flues or passages m, m,
which flues m, m, become highly heated by the waste heat as it passes
to the stack. The outer ends of the flues or passages m, m, are open
to the atmosphere, and air enters at their open ends, the air passing
through them being heated. The heated air from the heating flues or
passages m, m, passes by the radiating flues n, n, to the vertical
flues p, p, and from thence to the slits h opening into the flues g
between the fire-place a and crucible chamber d. The course of the
air along the heating passages or flues m, m, to the flues n, p, and from
thence to the slits h, will be readily traced by an examination of
Figure 3.
Figure 4 represents a vertical section of another furnace for the same
purpose as that last described, and Figure 5 is a part plan view and
horizontal section taken at different parts of the said furnace; the
horizontal section C, D, Figure 5, is taken on the line C, D, of Figure 4,
and the horizontal section A, B, Figure 5, is taken on the line A, B, of
Figure 4. In this arrangement the several furnaces constituting the
compound furnace are by preference situated side by side instead of
being inclined to one another.
The fire-place a, hopper b, crucible chamber d, and parts connected
therewith are the same as in the arrangement last described, and are
marked with the same letters of reference, but the flues or passages for
beating the air to be mixed with the gaseous fuel and for conducting the
heated air to the flue, between the fire-place and crucible chamber, are

page_text: F
arranged somewhat differently, that is to say, in this arrangement the
waste heat from each of the crucible chambers d passes to an inde-
pendent stack or chimney 7, and on either side the flue conveying thie
waste heat from the crucible chamber to the stack are air passages
(see the section Figure 5) in which the air is heated; these passages
open into other passages around the crucible chamber d, which convey
the heated air to the slits h, the said passages & opening into the slits h
at both ends.
Figures 6 and 7 represent cross sections of a furnace or muffle for
heating or annealing metallic articles constructed according to our
Invention; Figure 8 is an end or front elevation of the same; Figure 9
is a longitudinal vertical section of the same; and Figures 10 and 11
are horizontal sections of the same; Figure 12 is a perspective view of
the fire-place end of the furnace; the cross section, Figure 6, is taken
on the line I, J, of Figure 10; the cross section, Figure 7, is taken on
the line E, F, of Figure 10; the longitudinal vertical section, Figure 9,
is taken on the line C, D, of Figure 10; the horizontal section, Figure
10, is taken on the line A, B, of Figure 9; and the horizontal section,
Figure 11, is taken on the line G, H, of Figure 9. The same letters of
reference indicate the same parts in Figures 6 to 12.
a, a, are the fire-places; a³, the ash-pits; b, b, the fuel hoppers; and
c the muffle or closed chamber in which the metallic articles to be
heated or annealed are placed. Access to the said muffle is gained by
the opening d at the front end of the furnace, the said opening & being
closed by the counterbalanced sliding door e. Underneath the floor of
the muffle c are longitudinal flues f, f, and around the sides and top of
the said muffle are other flues g, h, with which the ends of the bottom
flues are in communication. The mixture of gaseous fuel and heated air
from the flues i, i, enters into a state of active combustion in the bottom
flues f, f, and the flame and heated air traverse the said flues f, ƒ, and
also the side flues 9, 9, and top flue / surrounding the muffle c; the .
said muffle is thereby heated. The waste heat from the muffle c descends
by the back flue k, k, into the horizontal passage. or flue 1, and from
thence by the end flue m to the stack. In the flue or passage 7 is a
horizontal pipe n, by preference of metal, open to the air. This pipe n is
heated by the waste heat passing along the flue 1, and the air traversing
the said pipe n is thus heated. The heated air is conveyed by the
transverse flue q to the scries of slits p, p, (see Figure 11) on either side,

page_text: the flues i, i, passing to the bottom flues ff, of the muffle c. This flue q
opens into the channels r, r, (see Figure 6) and the latter into the series
of slits p, p. The heated air is thus conveyed to the flues i, i, of the
double fire-place a, a, and mixing with the gaseous fuel supplied by the
partial combustion of the solid fuel in the said fire-place enters the
bottom flues f, f, and heats the muffle c, as herein-before described.
The arrangement or combination of parts described and represented
may be employed where the chamber containing the metallic articles to
be heated is open to the flame and heated air, the said flame and heated
air coming into contact wholly or partially with the metallic articles.
Figure 13 represents in longitudinal vertical section, Figure 14 in
horizontal section, and Figure 15 in cross section another furnace for
melting metals constructed according to our Invention. The section,
Figure 13, is taken on the line A, B, of Figure 14. The upper part of
the horizontal section, Figure 14, is taken on the line B, C, of Figure 13,
and the lower part of the horizontal section, Figure 14, is taken on the
line A, B, of Figure 13. The cross section, Figure 15, is taken on the
line D, E, of Figure 14. In this arrangement the heated air to be mixed
with the gaseous fuel on its way to the crucible chamber is heated by
the side walls of the fire-place and fuel hopper instead of by the waste
heat from the crucible chamber.
In the walls f, f, of the fire-place a and fuel hopper bare vertical
flues, g, g, their lower ends being open to the ash-pit c. The upper ends
of the said vertical flues g, g, open into horizontal flues h, h, at right
angles to the vertical flues, and the said horizontal flues open into the
ends of the cross slit i of the flue (see Figures 14 and 15). The
vertical flues g, g, are highly heated by the heat of the fire-place a, and
the air from the ash-pit c in passing through them is heated and the
heated air conveyed by the flues h, h, to the cross slit i, where it mixes
with the gaseous fuel in the flue on its way to the crucible chamber d.
The waste heat from the crucible chamber d in this arrangement
passes by the.flue m direct to the stack n.
This arrangement for heating the air may be applied to the furnaces
herein-before described, in place of the heating arrangements represented
in connection with the said furnaces.
Having now described the nature of our Invention, and the manner
in which the same is to be performed, we wish it to be understood that

page_text: we do not limit ourselves to the precise details herein described and
illustrated, as the same may be varied without departing from the
nature of our Invention; but we claim as our Invention of improve-
ments in furnaces for heating and melting metals and metallic
alloys,
Firstly. The several arrangements or combinations of parts herein-before
described and illustrated in the accompanying Drawings for generating
gaseous fuel and supplying a mixture of gaseous fuel and heated air
to the crucible chamber, muffle, or other chamber in which the
metals or metallic alloys to be heated or melted are placed, the
gas generators, the slits or openings, or series of slits or openings and
flues for supplying the heated air to the gaseous fuel passing to the
crucible or other heating chamber, being constructed and combined or
arranged substantially as described and illustrated.
Secondly. The several arrangements or combinations of parts sub-
stantially as herein-before described and illustrated in Figures 1 to 12,
both inclusive, of the accompanying Drawings, for heating the air to
be mixed with the gaseous fuel by means of the waste heat from
the crucible or other heating chamber.
Thirdly. The arrangement or combination of parts substantially as
herein before described and illustrated in Figures 13, 14, and 15 of
the accompanying Drawings, for heating the air to be mixed with the
gaseous fuel, that is to say, by means of flues in the walls of the fire-
place or gas generator communicating with the flue passing to the
crucible or other heating chamber.
In witness whereof, we, the said Charles Walker Torr and John
Johnstone have hereunto set our hands and seals, this Twenty-
eighth day of February, in the year of our Lord One thousand
eight hundred and seventy three.
Witness,
G. F. ASSINDER.
CHARLES WALKER TORR. (L.S.)
JOHN JOHNSTONE.
(L.S.)