Improvements in or relating to Calcining Furnaces.
Year: 1889

page_text: Date of Application, 12th Mar., 1889
Complete Specification Left, 12th Dec., 1859-Accepted, 18th Jan., 1890
PROVISIONAL SPECIFICATION.
Improvements in or relating to Calcining Furnaces.
I, ELIZABETH BARNSTON PARNELL of 148 St. John's Road, St. John's in the
County of Kent, Metallurgist, do hereby declare the nature of this invention to be
as follows:
This invention which relates to calcining furnaces has reference principally to that
class of muffle calcining furnaces which are horizontal and according to this invention
I cause these furnaces to rotate on rollers or the like so as to avoid the injurious
effects of unequal expansion and contraction and I also provide means for introducing
air, stean, oxygen or other gas into the calcining chambers.
The furnace which is built up advantageously-of cast-iron plates has preferably
six calcining chambers arranged around a central tube leading from the fore-chamber
and from which tube the heat is conveyed to the said calcining chambers the shell
surrounding which is of convenient form say hexagonal where six chambers are
employed. The fire grate is at one end and the heat therefrom traverses the central
tube to the stack at the other end of the furnace where are also provided branch
pipes for conducting the fumes from the calcining chambers to a condenser or to
discharge them into the atmosphere. At this end of the furnace there are also
provided pipes for introducing the air, steam, or gas to the several calcining
chambers, the steam being injected preferably through a central pipe surrounded
by others forming annular passagos to convey the gas, this arrangement also serving
to protect the saturated steam from the heat through which it is conveyed.
The calciner is provided with doors each of which preferably serves two chambers
and each chamber is fitted with a manhole at its end and lined with a suitable
refractory material.
The fire chamber door is at one side and the grate is built in with bricks supported
preferably on pedestals or columns.
The furnace may be rotated by worm gearing.
Suitable valves and dampers are provided for regulating the working of the
furnaces.
Deted this 10th day of March 1889
W. P. THOMPSON & BOULT,
COMPLETE SPECIFICATION.
Improvements in or relating to Calcining Furnaces.
I, ELIZABETH BARNSTON PARNELL of 148 St. John's Road, St. John's in the
County of Kent, Metallurgist, 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 which relates to calcining furnaces has reference principally to that
class of muffle calcining furnaces which are horizontal and according to this invention
I cause these furnaces to rotate on rollers or the like so as to avoid the injurious
effects of unequal expansion and contraction and I also provide means for introducing.
air, steam, oxygen or other gas into the calcining chambers.
The furnace which is built up advantageously of cast iron plates has preferably
six calcining chambers arranged around a central tube leading from the fire chamber
and from which tube the heat is conveyed to the said calcining chambers the shell
surrounding which is of convenient form say hexagonal where six chambers are
employed. The fire grate is at one end and the heat therefrom traverses the central

page_text: •
tube to the stack at the other end of the furnace where are also provided branch pipes
for conducting the fumes from the calcining chambers to a condenser or to discharge
them into the atmosphere. At this end of the furnace there are also provided pipes
for introducing the air, steam, or gas to the several calcining chambers the steam
being injected preferably through a central pipe surrounded by others forming
annular passages to convey the gas, this arrangement also serving to protect the
saturated steam from the heat through which it is conveyed.
The calciner is provided with doors each of which preferably serves two chambers
and each chamber is fitted with a manhole at its end and lined with a suitable
refractory material.
The fire chamber door is at one side and the grate is built in with bricks supported
preferably on pedestals or columns.
The furnace may be rotated by worm gearing.
Suitable valves and dampers are provided for regulating the working of the
furnaces.
In the accompanying drawings figure 1 is a view partly in sido elevation and
partly in longitudinal section of a furnace constructed according to this invention and
of which figuro 2 is a front end elevation: figs. 3, 4 and 5 are transverse sections
taken respectively on the lines a-b, -d and e-f of figure 1 and of these sections
figure 4 is taken as looking towards the fire chamber end of the apparatus; figure 6
is a detail view of a detached portion of figure 1.
Like letters indicate like parts throughout the drawings.
A is the shell or body of the furnace which may be of hexagonal cross section as
shown in figs. 2 to 5 and which may advantageously be built up of cast iron plates in
any convenient manner. B is the central tube which passes longitudinally from end
to end through the furnace A and is secured to the end plates A' and A² of the
furnace by any suitable means. B' are plates which divide the interior of the furnace
or that part between the shell A and tube B into compartments or chambers a' etc. of
which in the drawing there are six, but of which there may be more or less than six.
All the surfaces of the shell A tube B and partition plates B₁ presented towards the
interior of the chambers a¹ to a are lined or coated with suitable refractory material
which in the drawings is marked C which letter is also used to indicate generally the
refractory linings. D is the fire chamber which may be supported on columns D₁
and otherwise constructed. in the manner shown in the drawings or in any other con-
venient manner. D³ fig. 1 is the door or opening through which the fire is stoked
and D is the outlet through which pass the products of combustion from the fire
chamber D to the tube B, D being a damper by which the passage of such products
and the rate of combustion in the fire chamber D may be controlled and which
damper may be operated in any convenient manner. The outlet D³ from the furnace
is circular so as to admit of a sufficiently tight joint, being made between it and
the tube B of the revolving furnace and the opposite end plate A³ is similarly
provided with a central opening to admit of the tube B passing through it to be
suitably connected to the stationary or non-revolving smoke box E as shown most
clearly in figs. I and 5. E is the uptake from the smoke-box E.
The furnace A is supported on rollers F mounted on shafts F¹ which are carried in
suitable bearings G₁ formed on base plates G or in any other convenient manner.
These rollers directly or through the shafts F are rotated by means of worm
gearing to which rotary motion is transmitted through the shaft F³ and pulley F*
or their equivalent, from any suitable motor, and the friction between the rollers F
and frictional gear rings A upon the furnace will cause the furnace A to revolve.
The shaft passes through the plates or webs E' which support the smoke box Ę
and which may be provided with bearings for wholly or partially supporting the said
shaft which may be provided with a loose pulley F.
I prefer to rotate the furnace A slowly, and have found in a furnace of about
12 feet by 5 feet two revolutions in five minutes to give satisfactory results, but if
desired the said furnace may be rotated at a greater or less speed.
H, shown most clearly in figs. 1 and 4 are the outlet pipes from the chambers a¹-a

page_text: which radiate from the non-rotating horizontal outlet pipe H' of which as it were these
pipes H form radial branches. Each of these pipes H may have but three sides the
end of the chamber A providing the fourth side as shown in figure 1. This pipe H¹
passes through the smoke box E and is closed at its outer end as shown at H' and
between this closed end and the smoke box E it is provided with the pipe Hand
removable cleaning door H. The pipes H H and H³ are all lined with suitable
refractory material C and the pipe H³ is provided with baffle plates H which arrost
the progress and more or less prevent the escape of any of the valuable solid
particles carried off with the fumes leaving the chambers a-a which particles
strike against the said baffle plates and fall "back into the pipe H' from which they
may be collected through the before mentioned door H*.
He is a damper for regulating the passage through the pipe H³ of the fumes
from the chambers a-a. The pipe H³ may either be open directly to the atmo-
sphere or it may be connected to a suitable condenser by which, the valuable
constituents of the escaping fumes may be recovered before the said fumes are allowed
finally to escape into the atmosphere.
A are the doors through which the material to be calcined is charged into the
chambers aa and through which it is removed after it has been calcined. Each of
these doors as shown clearly in figure 3 is formed in the shape of a plug and may be
secured in its closed position by bolts A' which pass through Hanges A formed on the
outer ends of the plugs and screw into the shell of the furnace A or in other con-
venient manner. Each of the doors A* by fitting onto or against one of the partition
plates B serves two of the chambers a-a. The inner end of each door or plug A*
is coated with suitable refractory material as shown in figure 3.
A figures 1 and 2 are the manholes provided in one end of the furnace one to each
of the chambers a¹-a so that access to their interiors may be had for cleaning them
out. These manhole doors or covers as shown in figure 1 are each lined with
refractory material.
nay
J are pipes which as shown most clearly in figure 3 radiate from one common
centre where they are connected by a suitable joint J' figure 6 to the outer of the
three stationary concentric pipes JJ and J* which are respectively for admitting to
the calcining chambers air, gas and steam. The joint J as shown in figure
consist of a suitable stuffing box at the point of junction of the pipes J and adapted to
rotate around the outermost pipe J. Into the end of the pipe J' may be fitted a
suitably perforated plug or distance ring J which holds the adjacent ends of the
pipes J and J concentrically within the pipe J. The remote or outer ends of the
pipes JJ and J project through the closed end H2 of the pipe H₁ and are there
provided with a suitable arrangement of connections and valves J' to enable the
supply of air, stoam and oxygen or other gus to be regulated according to require-
ments. It is to be observed that the steam passes through the innermost pipe J
and that by this arrangement the surrounding pipes J2 and J³ and their contents
serve to protect the steam against becoming affected by the surrounding high
temperature so that the steam may be delivered to the calcining chambers a'-
in a saturated condition which is necessary for the proper treatment of the material.
In the operation of the before described apparatus the doors A' are first removed
and the material to be calcined therein is charged into the chamber a aª after
which the doors are again secured in position. The fire or products of combustion
from the fire chamber D are then admitted into the tube B and the furnace A is
rotated as before described. Steam air or oxygen or other gas or any two or all three
of these may then be admitted to the calcining chambers a'-a through the
pipes J J and J' in properly regulated quantities as may be determined by adjusting
the valves Jº.
The products of combustion passing from the fire chamber travel along the tube B
and between the radial pipes and H into the smoke box E (outside the tube H¹)
from which they finally escape into the atmosphere by way of the uptake E' all as
indicated by the arrows in figure 1. The fumes arising from the material under
treatment in the furnace leave the chambers a'-2' by way of the radial pipes H by

page_text: which they are conducted to the horizontal pipe H' whence they escape through the
pipe H by which they are conveyed to a condenser or directly into the atmosphere.
If desired the outer end of the pipe H³ may be provided with two branches one
of which will discharge the fumes leaving the chambers a¹a directly into the
atmosphere and the other will convey them to a condenser the two branches being
provided with dampers or valves to enable either or both of them to be thrown into
operation; besides this other modifications may be made without departing from
the essential features of this invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
• 1. In a calcining furnace a rotating body or shell such as A the interior of which
is divided into a number of longitudinal chambers substantially as herein described
and illustrated in the accompanying drawings.
2. In a calcining furnace the arrangement of the pipes J2 J3 J4 one within the
other so that the innermost pipe is protected against the surrounding high tempera-
ture so as to ensure that the steam which is passed through it to the calcining
chambers will be delivered in a saturated condition substantially as herein described.
3. In a calcining furnace a horizontal shell or body such as A mounted on
frictional driving rollers to which rotary motion is imparted by worm or equivalent
gearing substantially as herein described and illustrated in the accompanying
drawings.
4. In a calcining furnace the combination with a central stationary outlet pipe
such as H of a number of rotating branches such as H connecting it with the
calcining chambers substantially as herein described.
5. The general combination and arrangement of parts constituting the complete
calcining furnace substantially as herein described and illustrated in the accom-
panying drawings.
Dated this Twelfth day of December 1880
ELIZABETH BARNSTON PARNELL.
W. P. Thompson & Boult,
Agents for the Applicant.