Improvements in and connected with Furnaces for Treating Chemicals, Ores, or the like.
Year: 1894

page_text: Date of Application, 13th Nov., 1894
Complete Specification Left, 13th Aug., 1895-Accepted, 9th Nov., 1895
PROVISIONAL SPECIFICATION.
Improvements in and connected with Furnaces for Treating
Chemicals, Ores, or the like.
We WILLIAM THOMSON Engineer to the United Alkali Company Limited and
PHILIP JOHN WORSLEY a Director of the said Company both of Netham Chemical
Works Bristol do hereby declare the nature of this invention to be as follows:-
For many operations such for instance as the calcination of ultramarine with
sulphur, the distillation of shale for producing hydrocarbons, the calcination of
bicarbonate of soda or of soda-ash, the chlorination of silver ores the calcination of
blende in the manufacture of zine and for many other purposes mechanical furnaces
have been employed but in most of them the agitation or stirring of the material
to be calcined or treated has been accomplished by placing the said material on a
rotating bed while stationary ploughs and stirrers nixed and turned over the various
parts of the charge gradually brought under their influence by the rotation of the
bed.
Or the material was placed in a horizontal or inclined revolving cylinder,
when the stirring of the charge was caused by the revolution of the cylinder
sometimes assisted by breakers or agitators.
In all such furnaces however it is difficult to heat the charge without bringing
it into contact with the fuel gases, the rotating bed or the rotating cylinder
rendering the application of heat from without almost impossible.
It was also very difficult to collect any volatile products separately from the fuel
gases.
The object of our invention is to provide a furnace which permits heat to be
applied both from above and from below the furnace bed upon which the charge
rests to avoid when desired the contact of the fuel gases with the charge and their
intermixture with any volatile products which it may be desired to collect and to
combine mechanical stirring with these advantages.
According to our invention the furnace consists of a circular or annular bed
bounded by side walls. The bed and the side walls may be constructed of tiles and
bricks, or of iron or steel, or of other suitable material, the choice being made
according to the nature of the substance to be treated in the furnace and of the
volatile products, if any which are given off. The furnace bed is supported upon
walls the spaces between which serve as flues for the fuel gases by means of which
the bed is to be heated.
Above this bed we arrange a roof or cover capable of revolving, and carrying a
stirrer frame, which travels with the roof or cover. This roof or cover consists of
either one or two arches, according to whether the furnace is to be an open or a
closed furnace, that is to say according to whether the fuel gases are to be allowed
to come into contact with the charge or not. Whether consisting of one, or of two
arches this roof or cover is supported by a circular curb ring.
The curb ring is suspended from a frame work of girders, fastened to & carried
by a circular way plate supported by and travelling on bearing wheels carried upon
suitable foundations. If the furnace bed be made annular we prefer to make the
roof annular and to place within the central space an inner set of wheels supporting
an inner way plate, to give additional strength and support to the girders.
The arch, or arches, may be constructed of bricks, if the temperature be high.
When the temperature is not too high to permit the use of metallic plates we prefer

page_text: to make the lower arch if there be two arches, of metal plates. In that case we
use preferably curved plates in order to give direction to the strains.
The space between the bed and the arch immediately above the bel is enclosed
by the side walls and a vertical flange hung to the curb ring. This flauge reaches
down into and travels in a circular trough supported on the side walls and containing
sand or other loose material to form a seal or lute.
If the bed be annular there will be an internal or central as well as an external
or circumferential lute or seal.
By means of these seals or lutes we prevent the escape into the atmosphere or
into the fuel gases of any of the volatile products.
For the purpose of stirring the charge upon the bed, we attach to the girders
and curb rings, which carry the roof, a frame or frames supporting vertical stirrers
which are rotated by means of suitable gearing. The stirrers reach down to the
bed of the furnace passing through a wall box built into the arch or arches.
Where the stirrers pass through the revolving roof or cover they are suitably lnted
or packed to prevent the escape of volatile products, into the fuel gases or into the
atmosphere. In addition to the rotating stirrers we may fix a frame or frames
which carry ploughs set at an angle, such that, in travelling over the bed, the
material on the bed may be turned by them, or moved either round the bed, or
from the centre to the circumference, or vice versa. These ploughs may be fixed by
frame work to the vertical flanges or they may pass through similar wall boxes or
apertures in the arch or arches and where they pass the lower arch they are luted
similarly to the rotating stirrers. Or we may use such ploughs alone without the
rotating stirrers if the material to be calcined or heated does not require much
agitation or is not suitable to be acted upon by rotating stirrers. In order to heat
the space under the arch or between the arches, we build on the roof a fireplace or
fireplaces, the fuel gases from which pass through suitable apertures in the arch or
the upper arch into the space beneath it and are withdrawn through similar
apertures by means of flues or pipes which lead to a chimney. The connections of
these outlet flues to the chimney are made by means of a sandlute. Or the chimney
may be fixed on the roof of the furnace and may revolve with it. Or the space
below the arch or between the arches may be heated by producer gas which is
conveyed into it by means of pipes or passages and saudlutes, as is also the air
necessary for combustion. The gas being burnt below the arch or between the
arches furnishes the necessary heat and the products of combustion pass away into
a chimney as described.
The furnace may receive its charge through an aperture or apertures in the roof
or side wall and the charge may be withdrawn from an outlet in the furnace bed.
For many applications of the furnace we prefer to work continuously, in which
case we feed the material to be calcined, or heated, by means of a suitable
mechanical arrangement such as a screw, or worm, at or near the circumference of
the bed. The charge whilst being heated is kept stirred and mixed, by the
revolving stirrers. The ploughs turn the charge over and cause it to move
circumferentially along and gradually across the bed, till it is in a position to be
pushed into the outlet provided for that purpose and thence into wagons or other
receptacle placed beneath the furnace to receive it. Thus we obtain a continuous
and automatic treatment and discharge of the material.
If the material, during calcination, gives off volatile products, which require
collecting either by reason of their value, or by reason of their noxious character,
we employ the furnace with two arches and we provide an outlet for the gaseous,
or volatile products, in the side walls, of the furnace bed, which may be connected
by pipes or passages to apparatus for condensing, or absorbing, or otherwise treating
or utilising them.
Dated this 12th love of Noveumban 1001
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents,

page_text: Improvements in and connected with Furnaces for Treating
Chemicals, Ores, or the like.
We, WILLIAM THOMSON, Engineer to the United Alkali Company Limited,
and PHILIP JOHN WORSLEY, a Director of the said Company, both of Netham
Chemical Works, Bristol, 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 :-
For many operations, such, for instance, as the calcination of ultramarine with
sulphur, the distillation of shale for producing hydrocarbons, the calcination of
bicarbonate of soda, or of soda-ash, the chlorination of silver ores, the calcination
of blende in the manufacture of zinc, and for many other purposes, mechanical
furnaces have been employed but in most of them the agitation, or stirring of the
material to be calcined or treated has been accomplished by placing the said
material on a rotating bed, while stationary ploughs and stirrers mixed, and turned
over, the various parts of the charge gradually brought under their influence by
the rotation of the bed. Or the material has been placed in a horizontal, or
inclined, revolving cylinder, the stirring of the charge being caused by the
revolution of the cylinder, sometimes assisted by breakers, or agitators.
In all such furnaces, however, it is difficult to heat the charge without bringing
it into contact with the fuel gases the rotating bed, or the rotating cylinder,
rendering the application of heat from without almost impossible.
It has also been very difficult to collect any volatile products separately from
the fuel gases.
The object of our invention is to provide a furnace which permits heat to be
applied from above and from below the furnace bed upon which the charge rests,
to avoid, when desired, the contact of the fuel gases with the charge, and their
intermixture with any volatile products which it may be desired to collect, and to
combine mechanical stirring with these advantages.
In order that our invention may be more clearly understood we have annexed
hereto drawings, wherein
Figure 1 is a vertical section, Figure 2 is a plan and Figure 3 is an elevation of
an annular furnace or roaster constructed according to this invention.
Figure 4 is a plan of the roof of the said furnace.
Figures 5, 6 and 7 are sections of parts of the furnace shewing respectively the
outlet for gaseous products from the furnace, the discharge opening for the
materials treated, and an automatic arrangement for feeding the furnace.
Figures 8, 9 and 10 are vertical sections shewing modified constructions of
furnaces constructed according to this invention.
The same, or corresponding, parts are marked with the same letters of reference
in all the figures of the drawings.
According to our invention the furnace consists of a circular, or annular, bed A,
bounded by side walls B. The bed and the side walls may be constructed of tiles
and bricks, or of iron, or steel, or of other suitable material, the choice being made
according to the nature of the substances to be treated in the furnace and of the
volatile products, if any, which are given off. The furnace bed is supported upon
walls C, the
spaces C, between which, constitute flues for the fuel gases by means
of which the bed is to be heated.
Above this bed we arrange a roof, or cover, capable of revolving and carrying
a stirrer frame D, which travels with the roof, or cover.
This roof, or cover,
consists of either one, or two, arches (two are shewn in the drawing and marked E
and F) according to whether the furnace is to be an open, or a closed, furnace, that
is to say, according to whether the fuel gases are to be allowed to come into

page_text: contact with the charge, or not. Whether consisting of one, or of two, arches this
roof, or cover, is supported by a circular curb ring G suspended from a frame work
of girders H, fastened to, and carried by, a circular way plate I, supported by,
and travelling on, bearing wheels J, carried upon suitable foundations. If the
furnace bed be made annular, as in the example illustrated by Figures 1 to 7
and 10, we prefer to make the roof annular and to place within the central space
an inner set of bearing wheels K, supporting an inner way plate L, to give
additional strength and support to the girders H.
The arch, or arches E and F, may be constructed of bricks as shewn in
Figures 8 and 10 if the temperature be high. When the temperature is not
too high to permit the use of metallic plates we prefer to make the lower arch F,
if there be two arches, of metal plates as shewn in Figures 1 and 9, in which
case we use preferably curved plates in order to give direction to the strains.
The space between the bed A and the arch, immediately above the bed, is
enclosed by the side walls B, and a vertical flange M, hung to the curb ring G.
This flange reaches down into, and travels in, a circular trough N, supported on
the side walls B, and containing sand, or other loose material, to form a seal,
or lute.
If the bed be annular there will be an internal, or central, lute, or seal, P, Q,
as well as an external, or circumferential lute, or seal M, N.
By means of these seals, or lutes, we prevent the escape into the atmosphere,
or into the fuel gases, of any of the volatile products from the materials being
treated in the furnace."
For the purpose of stirring the charge upon the bed A, we attach to the
girders H a frame, or frames, supporting a vertical stirrer, or vertical stirrers S,
which are rotated by means of suitable gearing; shewn as consisting of a fixed
circular series of teeth d, and transmitting wheel d², and spur wheels on the shaft of
each stirrer S. The stirrers reach down to the bed A of the furnace passing
through a kind of wall box, or bearings, built into the arch, or arches. Where
the stirrers S pass through the revolving roof, or cover, they are suitably luted,
or packed, to prevent the escape of volatile products, from the interior of the
furnace, into the fuel gases, or into the atmosphere. In addition to the rotating
stirrers S, we may fix a frame, or frames, which carry ploughs T, set at an angle,
such that, in travelling over the bed A, the material on the bed may be turned by
them, or moved either round the bed, or from the circumference to the centre;
or they may be arranged to move the material from the centre to the circumference.
The shafts of these ploughs T, may be fixed by framework to the vertical flanges,
or members, of the girders, or they may pass through wall boxes, or apertures,
like those for the shafts S, in the arch, or arches, and where they pass through
the revolving roof, or cover, they are luted similarly to the rotating stirrers S.
Or we may use such ploughs T alone without the rotating stirrers if the
material to be calcined, or heated, does not require much agitation, or is not
suitable to be acted upon by rotating stirrers. In order to heat the space U,
under the arch, or between the arches, we build on the roof a fireplace, or fire-
places V, the fuel gases from which pass through suitable apertures in the arch, or
the upper arch E, into the space U beneath it and are withdrawn through similar
apertures by means of flues, or pipes, W, which lead to a chimney. The connec-
tions of these outlet flues to the chimney are made by means of a sand lute X.
the chimney may be fixed on the roof of the furnace and may revolve with it.
Or the space U below the arch or between the arches, may be heated by
producer gas which is conveyed into it by means of pipes, or passages, and sand
lutes as is also the air necessary for combustion. The gas being burnt below the
arch, or between the arches, furnishes the necessary heat and the products of
combustion pass away into a chimney as described.
Or
The furnace may receive its charge through an aperture, or through apertures,
in the roof, or side wall, and the charge may be withdrawn from an outlet in the
furnace bed.

page_text: For many applications of the furnace we prefer to work continuously, in which
case we feed the material to be calcined, or heated, by means of a suitable
mechanical arrangement, such as a screw, or worm Y, at, or near, the circumference
of the bed A. The charge, whilst being heated is kept stirred, and mixed, by
the revolving stirrers S, if they be used. The ploughs T, if they be used, turn
the charge over and cause it to move circumferentially along, and gradually
the bed, till it is in a position to be pushed into the outlet Z provided for
that purpose and thence into wagons Z2, or other receptacles, placed beneath the
furnace to receive it. Thus we obtain a continuous and automatic treatment and
discharge of the material.
across,
If the material, during calcination, gives off volatile products, which require
collecting, either by reason of their value, or by reason of their noxious character,
we employ the furnace with two arches E and F and we provide an outlet, or
outlets, Z (Figure 5) for the gaseous, or volatile products, in the side walls of the
furnace bed, which outlet or outlets may be connected by pipes, or passages, to
apparatus for condensing, or absorbing, or otherwise treating, or utilising, them.
Clearing openings 9 closed by doors are formed in the curb rings G, R, for
removing soot, or flue dust, from the arch F. Openings b, provided with doors,
are formed in the side walls B for the inspection, or manipulation, of the materials
during the process of calcination. The roasting bed A, may be heated by a
fireplace, or fireplaces, as at a, Figure 2, or it may be heated by producer, or other,
gas, by admitting atmospheric air, and burning the gas in the flues C, the products
of combustion passing into a chimney.
The furnace roof and its attachments may be rotated by any suitable means.
In the drawing it is shewn as being provided with a circular series of teeth at h,
driven by gearing h³, from any convenient prime mover.
Figures 8 and 9 shew disc forms of furnaces, that is furnaces in which the roof
or cover is supported at the outer edge only, and have no central opening. In
Figure 8 two brick arches are shewn and in Figure 9 a brick upper arch and a
metal lower arch are shewn. In Figure 10 a furnace like that shewn in Figure 1
is illustrated but with both the upper and lower arches made of brick. The
stirrers, or ploughs, are not shewn in Figures 8, 9 and 10, but they are of course
used therewith as hereinbefore explained.
The furnaces or roasters constructed according to this invention, are applicable
for any of the purposes hereinbefore mentioned, or for other purposes, such, for
example, as for use in the manufacture of sulphate of soda, or for any other
processes, or manufactures, to which they are, or may be, applicable.
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 :-
1. A furnace, or roaster, suitable for the purposes mentioned, and consisting of
a stationary bed and a rotating roof, or cover, enclosing between them the space
in which the materials are treated, and means for applying heat thereto (either
above or below the bed or both) and stirrers, or ploughs, or both, carried by, and
revolving with, the roof and means for charging the furnace or roaster and for the
discharge thereof substantially as hereinbefore described.
2. A furnace, or roaster, suitable for the purposes mentioned, and consisting of
a stationary bed and a rotating roof, or cover, enclosing between them the space
in which the materials are treated, the said roof, or cover, carrying stirrers, or
ploughs, or both; and being double with a space between, and means for applying
heat in this space or both in this space and below the bed of the furnace without
contact of the fuel gases with the contents of the furnace, or roaster, and means
for charging the furnace or roaster and for the discharge thereof, substantially as
hereinbetore described.
3. The several arrangements and combinations of parts constituting the furnaces,
or roasters, suitable for the purposes mentioned; substantially as hereinbefore

page_text: described and illustrated in Figures 1 to 7, and in Figure 8, Figure 9, and Figure 10,
of the accompanying drawings.
Dated this 13th day of August 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.