IMPROVE- MENTS IN FURNACES OR APPARATUS FOR BURNING, CALCINING, OR ROASTING SULPHUR ORES, SPENT OXIDE OF IRON, AND OTHER MATERIALS, AND APPARATUS FOR SEPARATING DUST AND SOLID IMPURITIES FROM THE GASES OBTAINED, THE SAID IMPROVEMENTS BEING ALSO APPLICABLE TO APPARATUS FOR USE IN THE PURIFICATION OF COAL GAS OR OTHER ANALOGOUS OPERATIONS "
Year: 1883

page_text: IN
ETTERS PATENT to Isaac Shimwell McDougall of Irk Vale, Chadderton,
near Manchester, in the County of Lancaster, for an Invention of "IMPROVE-
MENTS IN FURNACES OR APPARATUS FOR BURNING, CALCINING, OR ROASTING
SULPHUR ORES, SPENT OXIDE OF IRON, AND OTHER MATERIALS, AND
APPARATUS FOR SEPARATING DUST AND SOLID IMPURITIES FROM THE GASES
OBTAINED, THE SAID IMPROVEMENTS BEING ALSO APPLICABLE TO APPARATUS
FOR USE IN THE PURIFICATION OF COAL GAS OR OTHER ANALOGOUS
OPERATIONS
"
PROVISIONAL SPECIFICATION left by the said Isaac Shimwell McDougall
at the Office of the Commissioners of Patents on the 16th August 1883..
ISAAC SHIMWELL MCDOUGALL of Irk Vale Chadderton near Manchester in the
County of Lancaster "IMPROVEMENTS IN FURNACES OR APPARATUS FOR BURNING
CALCINING OR ROASTING SULPHUR ORES SPENT OXIDE OF IRON AND OTHER
MATERIALS AND IN APPARATUS FOR SEPARATING DUST AND SOLID IMPURITIES
FROM THE GASES OBTAINED THE SAID IMPROVEMENTS BEING ALSO APPLICABLE
TO APPARATUS FOR USE IN THE PURIFICATION OF COAL GAS OR OTHER ANALOGOUS
OPERATIONS."
My Invention relates principally to furnaces or apparatus for burning calcining
or roasting sulphur ores, spent oxide of iron or other materials and is especially
adapted for producing sulphurous acid gas for conversion into sulphuric acid or for
other purpose.
The apparatus consists of a series of superposed chambers or floors furnished
with rakes or agitators and feeders by means of which the materials under
treatment are fed continuously through the series of chambers whilst being
submitted to the burning calcining or roasting process. The said rakes or
agitators and feeders are fixed to a main shaft passing through the chambers
which are provided with openings or passages from chamber to chamber alternately
at the centre and at the side so that the materials are passed by the said rakes

page_text: across each floor and from chamber to chamber throughout the series of chambers
constituting the furnace until the said materials are finally delivered out of the
said furnace. The said shaft and the said rakes when made of cast iron and
exposed to great heat are liable to warp and break when strained. To obviate this
I make the said shaft and rakes hollow and provide them with wrought metal
pipes fixed in their interiors and forming an inner wrought metal lining to the
cast metal. In order to render it possible to replace the shaft without removing
the floors of the Chambers I provide the shaft at each place where the rakes are
to be fixed thereto with shoulders and the rakes with a forked inner end which
embraces the shaft. A pin or cutter is passed through the forked ends of the rake
to secure it to the shaft and by withdrawing this cotter the rakes may be readily
removed from the shaft which can then be withdrawn from the furnace for renewal
or repair.
'
In order that that the shaft may be readily removed for repairs or other purpose
after the rakes are removed as hereinbefore described (without the necessity for
breaking the floors) on each alternate floor where the material passes through the
passage at the side I furnish the central floor box through which the shaft passes
with a flanged moveable cover resting on a flange on the floor box and fitting
round the shaft by which arrangement the shaft can readily be removed through
the floors and out at the top of the furnace.
A loose piece of hard steel may be fixed to the bottom of the shaft working
on a loose steel disc_so_that_the_said loose pieces take the_wear_and_when_worn_can_
be readily replaced without necessitating the renewal of the shaft.
In order to adapt the furnace for use for treating various kinds of materials
requiring submission to the heat of the furnace for a longer or shorter period
I provide in addition to the feeding hopper at the top other hoppers communicating
with floors at different levels through which the different materials may be fed at
the same time.according to_the_number_of..the chambers through. which they are.
required to pass-In order to dry the materials (where desirable) before they are
fed into the chamber I provide a floor outside the roof of the top chamber and I
furnish this floor with a rake so that the material being fed on to the said floor is
dried thereon and then by the operation of the said rake is fed therefrom into the
top chamber.
My Invention relates further to the provision of means for freeing the gases
from dust and solid impurities immediately after leaving the furnace and before
they pass to the Chambers or vessels in which their utilization or chemical
combination or treatment takes place. These means consist of a chamber divided
by a series of plates or baffles having holes or perforations therein The holes in
the one plate or baffle are not opposite those in the adjacent plates or baffles so
that the dust and solid impurities are impeded by the said plates as the gases
pass through the holes and the said dust and solid impurities fall to the lower part
of the chamber. The bottom parts of the said plates or baffles are without holes
and a damper is provided between each plate or baffle which on being moved into
position closes in the space between the lower unperforated parts of the said plates
or baffles and cuts off the enclosed space so that the gas has not access thereto.
These dampers are for the purpose of thus being placed in position to allow of
the dust and solid impurities being removed from between the plates without
permitting access of air to the gas. The said chamber can be made to answer the
purpose of a nitre oven by providing bearing bars and other parts within the said
chamber for supporting the nitre pots and suitable doors for the charging and
romoval of the nitre pots.
The vertical shaft may be rotated by any convenient gearing from the source of
motive power and connections may be made from the said gearing for operating
charging pistons for pushing the material from the hopper or hoppers on to the
drying floor or into the chambers of the furnace.
Each chamber may be provided with a man-hole or man-holes for gaining access
thereto when required.

page_text: If preferable when it is important to burn either small pyrites or other suitable
material or sulphur compounds so as to occasion the least possible amount of dust
instead of the arrangement of floors rakes and dust box heroinbefore described I
construct a chamber with a long horizontal or approximately horizontal bed the
said chamber being provided with a series of perpendicular shafts and rakes so
arranged so as to act upon the material lying upon the said bed to take it forward
therealong. The rakes have teeth set at an angle to feed from the circumferenco
to the centre of each shaft. With this arrangement of working it is necessary to
adjust the teeth rakes in such a manner as to carry the material forward regularly
from one end of the furnace to the other. This is done by only slightly slanting the
teeth of the first rake and increasing the slant of the teeth of cach succeeding rake as
is found necessary for the equal distribution of the material, each alternate shaft being
made to move at the same speed and in the opposite direction to that of the shaft
next to it. Any number of shafts, each supporting a rake, may be fixed in a
straight line as may be required. The chamber is made sufficiently-wide for the
revolution of one rake and the length of the chamber is made sufficiently long for
the number of shafts and rakes required. The material to be burned is fed in at
one end of the chamber and delivered out of the chamber through a hole provided
in the floor near to the centre of the last shaft the said material falling down an
inclined shoot and being carried away by a screw or other suitable mechanical
arrangement in such a manner as to create no dust in delivery from the furnace.
By this arrangement the material may be fed into the furnace and carried forward
to the last rake in the Chamber upon the same horizontal plane and the air to
support combustion is fed into the chamber above the level of the material on the
floor, either at one place or more as is found convenient. By this means tho
steady and regular moving of the burning material is accomplished without it
having to fall from Chamber chamber to the gases and thus the chief cause of dust
is obviated.
The outer casing of the furnace is made of suitable cast iron plates with bearers
bolted together and completely cased inside with fire bricks or fire tiles and in
other respects the feeding of the material and the working of the furnace is
conducted in like manner as is hereinbefore described with regard to the vertical
furnace.
The apparatus herein before described it will be evident may be adapted generally
for use for turning over stirring or agitating materials to expose the same to heat,
or the action of air gases or vapours or to expose gases or vapours to the purifying
or other action or effect of the said materials either in a heated or in a cold
condition,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Isaac Shimwell MoDougall in the Patent Office on the 16th February
1884.
ISAAC SHIMWELL MCDOUGALL of Irk Vale Chadderton near Manchester in the
County of Lancaster "IMPROVEMENTS IN FURNACES OR APPARATUS FOR BURNING
CALCINING OR ROASTING SULPHUR ORES, SPENT OXIDE OF IRON AND OTHER
MATERIALS AND IN APPARATUS FOR SEPARATING DUST AND SOLID IMPURITIES
FROM THE GASES OBTAINED THE SAID IMPROVEMENTS BEING ALSO APPLICABLE
-TO-APPARATUS-FOR-USE IN THE PURIFICATION OF COAL GAS OR OTHER ANALOGOUS.
OPERATIONS"
My Invention relates principally to furnaces or apparatus for burning calcining
or roasting sulphur ores spent oxide of iron or other materials and is especially
adapted for producing sulphurous acid gas for conversion into sulphuric acid or for
other purposes I will describe my Invention with reference to the accompanying
drawing Figure 1 of which represents in vertical section an arrangement of vertical
furnace or apparatus according to my Invention Figure 2 shewing in clevation
Figure 3 in transverse section (on the line 1. 2 Figure 2) and Figure 4 in sectional
plan an apparatus in connection therewith constructed according to my Invention
for removing dust-and-solid-impurities-from-the gases passing from the furnace
Figures 5 and 6 are vertical and horizontal sections of the. details of the rakes
drawn to a larger scale and Figures 7 8 and 9 are respectively a longitudinal section
a sectional plan and a transverse section of a horizontal arrangement of the furnace
or apparatus as hereinafter described. The dotted parts in Figure 7 shew a further
modification wherein the vertical and horizontal arrangements are combined as
also hereinafter described. Referring to Figure 1. the apparatus consists of a series
of superposed chambers or floors A furnished with rakes or agitators and feeders b
(alternately reversely angled). by means of which the materials under treatment
are fed continuously through the series of chambers A whilst being submitted to
the burning calcining or roasting process. The said rakes or agitators and feeders b
are fixed to a main shaft B passing vertically through the chambers A which are
provided with openings or passages a froin chamber to chamber alternately at the
centre and at the side so that the materials are passed by the said rakes b across
each floor and from chamber to chamber throughout the series of chambers
constituting the furnace until the said materials are finally delivered out of the
said furnace by the outlet at C. The said shaft and the said rakes when made of
cast iron if exposed to excessive heat are liable to warp and break when strained.
To obviate this I make the said shaft and rakes hollow and provide them with
wrought metal pipes fixed at their interiors and forming an inner wrought metal
lining to the cast metal. This is shewn in Figures 5 and 6 where the wrought
metal lining to the shaft is marked B' and the wrought metal lining to the rake
is marked b In order to render it possible to replace the shaft B without
removing the floors of the chambers A. I provide the said shaft at each place
where the rakes are to be fixed thereto with shoulders and the rakes with a
forked inner end b which embraces the shaft B. A pin or cotter 6° is passed
through the forked ends b' of the rake b to secure it to the shaft B and by with-
drawing this cotter 6 the rakes b may be readily removed from the shaft B which
can then be withdrawn from the furnace for renewal or repair.
In order that the shaft may be readily removed for repairs or other purpose
after the rakes are removed as herein before described (without the necessity for
breaking the floors) on each alternate floor where the material passes through a
passage at the side. I may furnish the central floor box through which the shaft

page_text: passes with a flanged moveable cover resting on a flange on the floor box and
fitting round the shaft by which arrangement the shaft can readily be removed
through the floors and out at the top of the furnace.
I may provide a floor outside the roof of the top chamber as shewn at D
Figure 1 and furnish this floor with a rake or agitator or feeder b¹ (or two or
more of them) so that the material being fed on to the said floor D is dried thereon
and then by the operation of the said rake is fed therefrom into the top
chamber
My Invention relates further to the provision of means for freeing the gases
from dust and solid impurities immediately after leaving the furnace and before
they pass to the chambers or vessels in which their utilization or chemical com-
bination or treatment takes place. These means are illustrated by Figures 2. 3
and 4 and consist of a chamber E divided by a series of plates or battles F having
holes or perforations F¹ therein. The holes in the one plate or baffle are not
opposite those in the adjacent plates or baffles so that the dust and solid impurities
are impeded by the said plates as the gases pass through the holes and the said
dust and solid impurities fall to the lower part of the chamber. The bottom parts
of the said plates or baffles are without holes and a damper G is provided between
each two plates or baffles F which damper G on being moved into position closes
in the space between the lower unperforated parts of the said plates or baffles F
and cuts off the enclosed space so that the gas has not access thereto. Theso
dampers G are for the purpose of thus being placed in position to allow of the
dust and solid impurities being removed from between the plates F by the
openings g covered by doors without permitting access of air to the gas. The said
chamber É can be made to answer the purpose of a nitre oven by providing
bearing bars E¹ within the said Chamber for supporting the nitre pots (as at I)
Suitable doors as at J are provided for the charging and removal of the
nitre pots
The vertical shaft may be rotated by any convenient gearing from the source
of motive power and connections may be made from the said gearing for operating
charging pistons for pushing the material from the hopper or hoppers on to the
drying floor or into the Chambers of the furnace
Each chamber may be provided with a man hole or manholes for gaining access
thereto when required
If preferable when it is important to burn either small pyrites or other suitable
material or sulphur compounds so as to occasion the least possible amount of dust
instead of the arrangement of floors and rakes, hereinbefore described I construct a
Chamber with a long horizontal or approximately: horizontal bed as shewn in
Figures 7. 8 and 9 constituting a series of Chambers following each other the said
Chambers being provided with a series of perpendicular shafts B and rakes or
agitators and feeders b so arranged as to act upon the material lying upon the
said bed to take it forward thero along The teeth of the rakes or agitators and
feeders are set an angle to feed from their circumference towards the centre of
cach shaft-Each alternate shaft b is made to nove at the same speed and in the
opposite direction to that of the shaft next to it and this may be effected in any
desired manner for example by an arrangement of gearing as shewn in figure 7-
Any suitable number of shafts each supporting a rake or agitator and feeder may
be fixed in a line as may be required-The chamber is made sufficiently wide for
the revolution of the rakes and the chamber is made sufficiently long for the
number of shafts and rakes required-The material to be burned is fed in from a
suitable hopper at one end of the chamber and delivered out of the chamber
through a hole provided in the floor near to the last shaft the said material falling
say down an inclined shoot and it may be carried away by a screw or other
suitable mechanical arrangement in such a manner as to create little or no dust
in delivery from the furnace-By this arrangement the material may be fed into
the furnace and carried forward to the last rake in the chamber upon the same
horizontal plano-(or approximately so) and the air to support combustion-is fed

page_text: into the chamber above the level of the material on the floor either at one place or
more as is found convenient--By this means the steady and regular moving of the
burning material is accomplished without it having to fall from chamber to
chamber and thus the chief cause of dust is obviated
The outer casing of the furnace may be made of any suitable material such
for example as cast or wrought iron plates with bearers bolted together and
completely cased inside with fire bricks or fire tiles and in other respects the
feeding of the material and the working of the furnace may be conducted in like
manner as is herein before described with regard to the vertical furnace
When it is desired to burn certain kinds of sulphur compounds containing low
percentages of sulphur so that ignition may commence as early as possible on their
entering the furnace and that as much as possible of the heat may be retained
within the furnace one or more additional tiers of the horizontal series of chambers
may be used with advantage this arrangement in effect combining the vertical and
horizontal methods heroin before described The full lines in Figure 7 shew one
series and these with the dotted lines shew two series or tiersOf course when
one series is used its upper part will be like the upper part of the top series in
Figure 7. It will be understood that more than two series or tiers may be used
if desired-The movement of the rakos is the same in each series When two or
more series or tiers are used the material is fed to and carried forward in the top
series to the end of that series and is then fed through an opening into and is
carried along to the opposite end of the next series and so with as many_scries. as-
may be used the material being finally discharged through a suitable outlet
provided in the bottom of the end Chamber of the lowest of the series
The-apparatus herein before described it will be evident may be adapted generally
for use for turning over stirring or agitating materials to expose the same to heat
or the action of air gases or vapours or to expose gases or vapours to the purifying
or other action or effect of the said materials.either in a heated or- in a-cold condition
or for saturating materials with gases for chemical purposes
I do not limit myself to the use of one rake or agitator and feeder in each
chamber as two or more may be used if desired-It will be evident that the dust
separating apparatus Figures 2. 3 and 4 may be combined with the horizontal form
of furnace Figure 7 if desired
Having now described and particularly ascertained the nature of my said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and
original and therefore claim as the Invention secured to me by the hereinbefore in
part recited Letters Patent is:
First, A furnace or apparatus for burning calcining or roasting sulphur ores, spent
oxides of iron and other materials or for use in the purification of Coal Gas or for
stirring or agitating materials to expose them to heat or the action of air gases or
vapours or to expose gases or vapours to the action of the materials so treated, the
said furnace or apparatus consisting of a number of superposed chambers provided
with revolving rakes or agitators and feeders and provided with openings or
passages from chamber to chamber, the said openings being situated alternately 4
at the centre and the side substantially as herein before described and illustrated
in the accompanying drawings.
Second, Providing the said rakes or agitators and feeders and the shaft to which
they are attached either or both of them of cast iron with wrought metal linings
or interiors substantially as hereinbefore described and illustrated by Figures 5 5
and 6 of the accompanying drawings.
Third, Attaching the rakes or agitators and feeders to the shaft by providing
the shaft with a projection and the rake or agitator or feeder with a forked end
through which a cotter is passed substantially as and for the purpose hereinbefore
described with reference to Figures 5 and 6 of the accompanying drawings.
Fourth, An apparatus for separating dust and solid impurities from gases, the
said apparatus consisting of a chamber divided into compartments with baffle

page_text: plates having perforations therein arranged so that the Gases passing therethrough
are baffled by the said plates and caused to deposit dust or solid impurities which
may be carried by them, the said apparatus being arranged substantially as horein-
before described and illustrated by figures 2, 3 and 4 of the accompanying
drawings whether or not it be provided with means for utilizing it as a mitre
oven,
Fifth, An apparatus for burning calcining or roasting Sulphur Ores or for analogous
purpose and for separating dust and solid impurities from the Gases obtained, the
said apparatus consisting of the combination of a furnace arranged under one or
other of the modifications substantially as hereinbefore described and of a dust
separator in connexion therewith, also arranged substantially as hereinbefore
described.
Sixth, A furnace or apparatus for burning calcining or roasting sulphur ores, spent
oxide of iron and other materials or for use in the purification of Coal Gas or for
stirring or agitating materials to expose them to heat or the action of air gases or
vapours or to expose gases or vapours to the action of the materials so treated, the
said furnace or apparatus consisting of a series of floors of a long horizontal or
approximately horizontal bed constituting a series of chambers following each
other and provided with a series of shafts and rakes or agitators and feeders
whether there be but one series of floors or chambers in the same plane or two or
more floors or chambers superposed substantially as hereinbefore described and
illustrated by Figures 7, 8 and 9 of the accompanying drawings.
In witness whereof I the said Isaac Shimwell McDougall have to this my
Specification set my land and Seal this fourteenth day of February. One thousand
eight hundred and eighty four.
ISAAC SHIMWELL M°DOUGALL_(L.S.)