Improvements in and relating to Rotary Furnaces and Apparatus for Treating Solids with Gases.
Year: 1897

page_text: Date of Application, 24th Dec., 1897-Accepted, 11th June, 1898
[Communicated from abroad by PAUL NAEF, Dr. of Philosophy, Chemical
Engineer, 15, 3rd Avenue, New Brighton, Staten Island, New York.]
Improvements in and relating to Rotary Furnaces and Apparatus for
Treating Solids with Gases.
I, PAUL DUNN, Merchant, 4, City Road, Birmingham, 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:―
The present invention relates to the class of rotary furnaces applicable to the
treatment of solids with gases, and it is specially valuable for the roasting or
drying of ores, and the decomposing of various chlorides, as for example mag-
nesium-oxychloride, with air or other gases for the manufacture of chlorine
products. It is also applicable for carrying out reactions based on catalytical
action, for example the production of sulphuric acid by treating sulphurous acid
gas with metallic oxides, or platinum black, at high temperatures. The object of
the invention is to provide an improved rotary furnace, primarily intended to be
used with heating flues independent of the reaction chamber, so that the fire gas
need not be mixed with the gas produced by the decomposition of the ore or other
material; a furnace which will allow access to be had at all parts thereof for repair,
and which will afford a most intimate contact between the solid material treated, &
the gas, and will therefore effect as complete a decomposition of the solid material
as possible with a small excess of air or other gases.
The invention consists of the improved furnace as hereinafter described and
claimed, the main feature of the same being, primarily, a rotary cylinder furnace
with fire flues for heating the same, and gas, or oil, burners for the fire flues.
Also a construction which admits of access being had to all parts of the interior
of the rotary cylinder for repair; and further, certain details of construction and
arrangement.
In the accompanying drawings:-
Figure 1 is a longitudinal sectional view of a rotary cylinder furnace embodying
the features of the present invention.
Figure 2 is an end view of the furnace.
Figure 3 is a transverse section taken on the line 3-3 of Fig. 1.
Figure 4 is a transverse section taken through the exit flues on the line 4-4 of
Fig. 1.
Figures 5 and 6 are transverse sectional views illustrating modifications in details
of construction.
The cylinder shell, 10, Figs. 1 and 3, is of wrought or cast iron, or steel, and is
made in sectional ring sections, the individual pieces of each ring being flanged on
all four sides. The adjacent plates of a ring section are bolted together, as shown
at 11, Figure 3, and the several cylinder rings are bolted together as shown by the
joints 12, Fig. 1. Any of the plates can be removed to obtain access to the interior

page_text: of the cylinder or the lining. There are as many pairs of supporting rollers 13,
Fig. 1, as the length of the cylinder requires, & it is revolved by a worm 14, Fig. 1,
engaging with a rack circle 15, Fig. 1, carried by the cylinder. One of the support-
ing rollers is grooved, as shown at 16, Fig. 1, and a ✓ ring 17, Fig. 1, screwed on
in sections, engages therewith.
This holds the cylinder in position against the downward slip. The shell has
first a lining of thin tiles 20, Fig. 1 and 3, or a lining of non-conducting material
such as asbestos. Within this there is a lining of tile flues, 21, Fig. 1 and 3, made
with interfitting joints, projections 23, Fig. 1, fitting in grooves or recesses 24,
Fig. 1, to keep the flues 22, Fig. 1 and 3, tight. In the present case the lining has
eight of these flues running from one end of the cylinder to the other & forming
fire-flues for heating the furnace; but the number of flues will depend upon the
size of the cylinder, & may be more or less as desired.
The furnace is designed to be heated with gas, or oil burned within the mouth
of the flues, 22, Fig. 1 and 2. The attachment here shown is for gas, & in the
mouth of each flue 22 there is a gas burner 23ª, Fig. 1 and 2. The discharge end of
the cylinder is closed with a plate 242, Fig. 1 and 2, carrying a fire brick lining, 25,
Fig. 1, and having openings 26, Fig. 1 and 2, which register with the flues 22, also
discharge openings 27, Fig. 1, for the orc, just within the cylinder lining, & a
central air inlet pipe, 28, Fig. 1 and 2. The gas main is shown at 29, Fig. 1.
Turning freely thereon, by means of a stuffing box 30, Fig. 1, there is a set of
branch gas pipes 31, Fig. 1, leading to the several flue inlets, 26 Fig. 1 and 2, each
carrying a burner within the mouth of its flue. This spider frame of gas pipes is
carried by and revolves with the cylinder, and it may be supported by the radial
arms, 32, Fig. 1, extending out from a collar on the air inlet pipe 28, Fig. 1, or
each pipe may be attached to the plate 24", where the burner passes through the
plate. The air for the combustion enters each flue at the opening 26, Fig. 1. At
the feed end of the cylinder the fire gases are taken off through the ports 40, Fig. 1
and 4, opening into the annular flue 41, Fig. 1 and 4, in a stationary ring 42, Fig. 1
and 4. This ring is lined with fire brick and the flue 41 connects at the bottom, by
the flue 43, Fig. 1 and 4, with the flue 44, Fig. 1 and 4, leading to the chimney.
The end of the cylinder chamber is closed with the fire brick head 45, Fig. 1, having
the central opening 46, Fig. 1, and abutting against this end wall, is the face of a
brick lined stationary pipe 47, Fig. 1, registering with the hole 46, Fig. 1, and
through which the gas product of the furnace passes off for subsequent treatment.
The material is fed into the furnace through the pipe 48, Fig. 1 and 4, by means
of a mechanical feed 49, Fig. 1, the feed pipe 48 projecting through the opening 46,
in the cylinder head.
At the discharge end of the furnace the cylinder is closed by the fire brick-lined
plate 24, Fig. 1, as before mentioned, and the air or gas for the furnace chamber
enters through the central pipe 28, Fig. 1.
If hot air, on any acriform fluid other than cold air is employed proper connec-
tion with the inlet pipe 28, Fig. 1 is made for supplying the same. The discharge
openings 27, Fig. 1, are preferably fitted with the automatically controlled covers 50,
Fig. 1, as described in a prior patent granted to Paul Naef, No. 2736, Febr. 7, 1895. 4
We come now to the interior construction of the furnace chamber. The flue
lining tiles, 21, Fig. 1 and 3, are made with grooves 60, Fig. 3, at the joints extend-
ing parallel with the axis of the cylinder, and into these grooves are fitted the
outer edges of the partition tiles 61, Fig. 1 and 3. These partition tiles are made
with the apertures 62, Fig. 1 and 3, and with angular inner edges which interfit 5
and abut against each other; that is in the case of four radiating partitions, as here
shown, the inner edge of each plate presents oblique faces meeting at a central
edge and forming an angle of 90 degrees between the oblique faces. The edges of
the several abutting plates meet at the centre 64, Fig. 3, and the contiguous oblique
faces of the edges of the tiles fit together and mutually support each other along the 5
centre line of the cylinder. These tile partitions divide the cylinder in cross
section into quadrants, and the several apertured partitions form ore lifters for

page_text: successively elevating the ore and showering it through the apertures into the next
apartment.
-
The ore lifters are preferably arranged in several longitudinal sections, in the
present case three in number, with unpartitioned spaces, 63 and 64ª, Fig. 1, there-
between, and at the feed end of the cylinder there is a short space, 65, Fig. 1, with-
out ore lifting plates. The first section, beginning at the discharge end of the
furnace, has the ore lifting partitions in the position shown in section in Figure 3.
The second section has them in the position shown by the partitions 61° in
Figures 1 and 3. The third section is a counterpart of the first section. The con-
struction and arrangement produces an intimate contact between the ore and the air
or gas & it allows the removal of the ore lifting tiles without interfering with the
heating flue tiles, and vice versa, the latter can be renewed, as before described,
without disturbing the former.
In cases where the fire gases can be mixed with the gases produced by the
chemical reaction, the cylinder may be lined with a solid brick lining 70, as illus-
trated by Figure 5, the heating flues being omitted. The brick ore lifters, 71,
Fig. 5, are the same as above described except that the three sets are successively
offset thirty degrees from each other, as shown by the 'several positions 71, 71*,
and 71b, Fig. 5.
If the apparatus is to be used for drying at a low temperature, the heating flues
and ore lifters may be made of cast iron as illustrated by Figure 6. In this case the
cast iron lining flues 80, having the flanges or lugs 81 to which the iron ore-lifting
partitions 82, are bolted. These ore-lifting partitions are cast or made with the
oblique faces along their inner edges, which interfit and mutually support each
other at the centre of the cylinder, as in the case of the tile partitions above
described. When the plates are set therefore, they lock each other at the centre
& no fastening is required for them.
The furnace cylinder is ordinarily put up on an incline, so that the material
will pass through continuously by gravity. If however the same material is con-
stantly used, as for instance for cataltytical reactions, or if the reactions require too
long a time to admit of a continuous feed and discharge, the furnace is set on a
level. If it is constructed with a solid brick lining, doors can be arranged in the
periphery of the cylinder for emptying the furnace. The apparatus can with
advantage also be made for treating solids with gases in cases where by chemical
action superfluous heat is produced, which has to be abstracted for the successful
carrying out of the operation. Such cases are for instance the treatment of lime
with chlorine gas for the manufacture of bleaching powder, also the treatment of
carbonate of soda with carbonic acid gas for the manufacture of bicarbonate of
soda.
In such cases the flues in the lining may be employed to cool the cylinder instead
of heating it. The burners are omitted and cold air may be caused to circulato
through them, and it will be seen that, for such a purpose, the pipes leading
to the flues at the discharge end of the cylinder may be used to convey cold air,
instead of oil or gas. Further, if the iron construction illustrated by Figure 6 is
employed, water may be caused to circulate through the Hues as a still more
efficient cooling agent.
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. A revolving furnace having an ore chamber and a series of heating flues in its
periphery, with a system of fuel burners for the respective heating flues carried
by the furnace & revolving with it, as and for the purpose set forth.
2. A revolving furnace having an ore chamber and a series of heating flues in
its periphery, with a series of fuel burners for the respective heating flues, carried
by the furnace & revolving with it, in a combination with a stationary exit flue,

page_text: for the fire gases, registering with the heating flues, substantially and for the
purpose as set forth.
3. A revolving cylinder furnace having a series of heating flues in its periphery,
with a system of fuel burners for the several heating flues carried by the furnace &
revolving with it, in combination with a fuel supply pipe connected with the said
system of fuel burners by a moveable joint, substantially as & for purpose as set
forth.
4. A revolving furnace having an ore chamber divided into compartments by
longitudinal partitions, and having a series of heating flues in its periphery, with a
system of fuel burners for the several heating flues carried by the furnace and
revolving with it, in combination with a fuel supply pipe connected with the said
system of fuel burners by a moveable joint, substantially & for purpose as set
forth,
5. In a revolving cylinder furnace, a fire brick lining formed of blocks with longi-
tudinal flues therethrough and longitudinal grooves in the inner face of the lining
along the joints, in combination with fire-brick radial ore lifting partitions meeting
at the central axis of the cylinder and having the outer edges of the partitions
seated in the said longitudinal grooves, substanially as and for the purpose set
forth.
6. A revolving furnace having an ore chamber, the longitudinal partitions
dividing the chamber into compartments, and a series of heating flues in its
periphery, with a system of fuel burners for the respective heating flues carried by
the furnace and revolving with it, in combination with a stationary exit flue for the
fire gases registering with the ends of the heating flues, substanially as and for the
purpose set forth.
7. In a revolving cylinder furnace, the combination of the outer shell and the fire
brick lining having a series of longitudinal heating flues, with an end plate at the
discharge and having a central air opening for the furnace chamber and apertures
registering with the ends of the heating flues, and a series of full burners within
the mouths respectively of the several flues and carried by the revolving cylinder
together with a fuel supply pipe connected with the series of revolving fuel burners
by a moveable joint, substantially as and for the purpose set forth.
8. The combination with a furnace cylinder of a series of radial partitions having
angular central abutting edges, meeting at the centre of the cylinder and mutually
supporting each other, substantially as and for the purpose set forth.
9. The combination with a brick lined cylinder having longitudinal grooves in
the lining, of radial tile partitions with the outer edges of the partition tiles seated
in the grooves of the lining, and the central edges of the several tiles abutting, and
mutually supporting each other, substantially as for the purpose set forth.
10. The combination with a revolving cylinder lined with tiles and longitudinal
heating channels extending through the tiles and longitudinal grooves in the inner
face of the lining of radial partitions with the outer edges of the partition tiles
seated in the grooves of the lining, and the central edges of the several partition
tiles abutting and mutually supporting each other, substantially as and for the
purpose set forth.
11. A revolving furnace having radial tile partitions with the central edges of the
tiles abutting and mutually supporting each other, with the partitions arranged in
longitudinal offset sections, substantially as and for the purpose set forth.
Dated this 20th day of December 1897.