IMPROVEMENTS IN APPARATUS FOR THE MANUFACTURE OF CHLORIDE OF LIME
Year: 1875

page_text: LETTERS PATENT to William Riddell, of Foulden Road, Stoke
Newington, in the County of Middlesex, Civil Engineer, for the
Invention of "IMPROVEMENTS IN APPARATUS FOR THE MANUFACTURE OF
CHLORIDE OF LIME."
Scaled the 20th December 1875, and dated the 24th June 1875.
PROVISIONAL SPECIFICATION left by the said William Riddell at the
Office of the Commissioners of Patents, with his Petition, on the
24th June 1875.
I, WILLIAM RIDDELL, of Foulden Road, Stoke Newington, in the.
5 County of Middlesex, Civil Engineer, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN APPARATUS FOR THE MANUFACTURE
OP CHLORIDE OF LIME," to be as follows:-
The first part of my said Invention relates chiefly to an archimedean
screw of a novel construction, and the second part to a refrigerating.

page_text: device used in connection with said said screw in the manufacture of
chloride of lime.
The said screw is formed by winding a tube of metal around a hollow
shaft or spindle. The screw is advantageously formed in segments;
the said shaft or spindle is formed of iron pipes encased with lead if
required, and with flanges cast on the interior surface, by means of
which the lengths of pipe are bolted together; the said segments are
formed of lead or of iron lined with lead to prevent corrosion. These
segments may be formed entirely of lead by winding a lead pipe over
the centre shaft or of semicircular pieces of lead bolted or soldered to
the centre shaft, in such a manner that they leave a clear space between
each thread of the screw formed by said segments which are bound
together by means of metal bars extending horizontally from end to end
of the screw, and secured by metal screw hoops or other suitable means.
Iron rails are fitted over said bars which run upon friction wheels on
each side and sustain the weight of the apparatus which is made to
revolve on said wheels by cogs around its circumference working into
a toothed wheel or worm through which the necessary power is applied.
The end of the first segment is unclosed, which segment fits over a
corresponding opening in the centre shaft for the purpose of introducing
the lime which is effected by means of a small archimedean screw fixed
for the purpose in one end of said centre shaft or spindle. This screw is
worked by suitable gearing which may be made to feed the lime only
when the opening into. the segment is in a position to receive the
material, or the lime may be feed by means of a trough having valves
throughout its length, one only opening at a time in order to prevent
the escape of the gas; a similar device is fixed in the other or exit end
of the centre shaft for the purpose of discharging the chloride of lime.
A pipe is fitted loosely in the hollow spindle of this discharging screw
through which chlorine is admitted into the last segment of the
apparatus. Inside the segment stops or shelves are arranged at suitable
intervals by which the lime is prevented from being carried around in a

page_text: thread is closed in order to interrupt the passage of the gas, and thus
expose the lime to the action of the chlorine in a series of chambers in
its passage; and stops may also be, employed to break up the mass of
lime.
A serrated trough extending the length of the apparatus is placed
above the same into which cold water is introduced when it is desired to
cool the material in the apparatus. The water falls upon the segments
of the apparatus, by which means the lime is kept at a medium
temperature. The apparatus may be further cooled if found desirable
by the lower portion revolving in a tank or vessel of cold water.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Riddell'in the Great Seal Patent Office
on the 23rd December 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
RIDDELL, of Foulden Road, Stoke Newington, in the County of Middlesex,
Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of June, in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Riddell, Her special licence,
that I, the said William Riddell, my executors, administrators, and
assigns, or such others as I, the said William Riddell, my executors,
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 APPARATUS FOR THE MANUFACTURE OF CHLORIDE OF LIME," upon the
condition (amongst others) that I, the said William Riddell, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the

page_text: 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.
NOW KNOW YE, that I, the said William Riddell, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement, reference being had to the accompanying
Drawing forming a part of this Specification :-.
The first part of my said Invention relates chiefly to an archimedean
screw of a novel construction, and the second part to a refrigerating
device used in connection with said screw in the manufacture of chloride
of lime:
VI
DRAWING.
Figure 1 is a side elevation of my improved apparatus partly in section;
Figures 2 and 3 show detached portions of the same; Figures 4, 5, 6,
and 7 shew modifications of the said apparatus. Like letters indicate
the same parts throughout the Drawing.
In the construction of my improved apparatus, as shewn in Figure 1,
I use an oblong, square, or round tube of metal or other material which
is wound around a shaft or spindle, and forms thereby an archimedean
screw. The centre spindle a I prefer to make of cast-iron pipes which
may be cased with lead if necessary; these pipes are cast with inside
flanges a' which are joined by bolts and nuts a² or other suitable
means.
The thread of the screw can be made by winding an oval or round pipe
over the centre shaft or spindle a, or of semicircular pieces, as shewn
in Figure 5, or of segments of lead either bolted or soldered to the
centre shaft or may be constructed in segments, as shown in Figure 6,
made of iron or other metal lined with lead if required and fastened
together, and to the centre shaft or pipe a by means of screws or other
suitable devices. The segments are arranged to form a screw of such a
pitch on the centre shaft a that they leave a clear space between each
thread of the segments forming the screw.
The different threads or rows of segments after being fastened
together, and to the centre shaft are bound together by horizontal bars c

page_text: of iron reaching from end to end of the apparatus and placed at intervals
of the circumference. These bars when made of iron are fastened to
the segments 6 by screws or bolts or other convenient means; but when
these segments are made of lead they are retained in position by leaden
straps over the bars of iron. These horizontal iron bars are themselves
held in position by strong iron screw hoops d. At intervals of six to
ten feet of the length of the apparatus strong circular iron rails e aro
fitted over these horizontal bars c.
The entire vessel is made to revolve by one or more rows of cogs or
teeth around the circumference forming a toothed wheel which is
geared into another toothed wheel or worm wheel g. By means of this
gearing the vessel may be caused to revolve at any speed desired. The
said vessel is supported by the said circular rails upon friction wheels h
on each side of the apparatus, and which bear the entire weight of the
said apparatus.
The end of the centre shaft a is formed into a chamber a³ by means
of a metal plate a fixed in the shaft a on the inner side of an opening i
entering the end of the first segment or part of the screw. In this
chamber a³ is fixed a small archimedean feed screw j which delivers the
line through the orifice i into the first segment or part of the screw b.
The screw j is fed by means of a trough or hopper k, and the said screw
is worked by suitable gearing which may be made to revolve or feed
only when the opening into the segment can take in the material, or
the lime may be fed direct into the segments through a trough fitting
into the small chamber over the opening into the aforesaid first segment
or part of the screw. The hopper in the latter case is fitted with several
stops or valves throughout its length, one only being open at any time.
the others being closed in order to prevent an escape of gas.
i
The exit is constructed in a similar manner, the material falling from
the end segment into or upon an archimedean screw m by which it is
discharged through the pipe n into a suitable vessel o.
The spindle of
this archimedcan screw is hollow and through this spindle passes a pipe p
that must fit easily without friction into a second small chamber 9. The
outer end of this pipe is connected with the chlorine generator, the gas
being conveyed into the chamber q is thence conducted into the last
turn or part of the screw 6 by means of pipes » extending between the

page_text: chamber and the outer edge of the segments, and perforated with holes
to allow the escape of the gas; there should be four or more of these
pipes.
At various intervals of the inner circumference of the segments b
stops 6¹ are arranged from two to nine inches deep according to the form
of the apparatus. By these stops the lime is kept from going round in
a mass, being held on the shelf or stop until by the revolution of the
vessel it falls by gravitation through an atmosphere of gas to the bottom
of the vessel, when it is again lifted by other stops to fall again, and so
on until it reaches the exit opening, thus exposing a fresh surface at all
times during the progress of the operation to the action of the gas.
The apparatus can be lengthened to any required extent by the
addition of segments or pipes on further lengths of the centre shaft
arranged and put together as above described. By regulating the
length of the vessel and the speed of the revolution, the time necessary
for the completion of the process can be exactly determined.
When there is a probability of the heating of the material in the
apparatus by chemical decomposition the temperature can be reduced to
any required degree by maintaining a flow of water over and around the
segments of the apparatus from a serrated trough placed above the same;
it may also be further reduced by arranging the said apparatus with
its lower portion revolving in a tank or vessel of cold water.
Another form of vessel suitable for the purpose of my Invention is
shewn in Figure 7. This vessel has a female screw s, that is to say, a
screw or worm with annular spaces between the turns or spirals and the
central shaft a. This screw is formed of lead and fixed in a long
cylindrical vessel t lined also with lead; this vessel may be made in
two half cylinders afterwards bolted together. Some of the spirals of
the screw at intervals of its length are closed around the central shaft,
as slewn at s¹. By this construction the cylinder is broken up into a
number of chambers, the gas being thereby obstructed in its passage
through the vessel by the closed threads or spirals, and thus being
compelled to enter the next chamber by passing around and through one
thread of the screw. Stops are arranged on the outer circumference
of the screw to break up the lime during the revolution of the vessel, the.
same as in the apparatus herein-before described.

page_text: the refrigerating device and the other parts of the said apparatus
constructed, combined, and operating substantially as herein set forth.
In witness whereof, I, the said William Riddell, have hereunto
set my hand and scal, this Twenty-second day of December, in
the year of our Lord One thousand eight hundred and seventy-
fivc.
Witness,
ROWLAND G. Brown, ·
8, Southampton Buildings,
London.
WILLIAM RIDDELL. (L.S.)