Improvements in or relating to Apparatus for Treating and Extracting Solids with Washing Liquids or Solvents.
Year: 1896

page_text: Date of Application, 23rd Jan., 1895
Complete Specification Left, 23rd Oct., 1896-Accepted, 23rd Jan., 1897
PROVISIONAL SPECIFICATION.
Improvements in or relating to Apparatus for Treating and
Extracting Solids with Washing Liquids or Solvents.
1, THOMAS FAIRLEY of 17 East Parade, Leeds in the County of York,
Chemist, do hereby declare the nature of this invention to be as follows:-
Screw conveyors working in troughs, tubes or cylinders are used for conveying
wet or dry materials in various manufacturing operations. By their means a solid
material more or less finely divided can be carried upwards or forwards through a
tube or cylinder against a flow of washing liquid or solvent passing in the opposite
direction. With a supply of power to rotate the shaft of the screw conveyor and
proper adjustment of the liquid entering and leaving the apparatus a continuous
extractor may be thus obtained.
My invention relates to a special form of screw conveyor for the manufacture
and purification of certain salts. Such apparatus is also well adapted for the
extraction or separation of many substances from nixtures by means of water,
alcohol or other liquid solvents.
The improved form of screw apparatus may be described as in its simplest form
derived from an ordinary screw conveyor by dividing it along a section passing
lengthwise through the axis of the shaft of the screw into two equal and similar
parts. If now the free ends of the divided shaft be fitted with sleeves passing
over them the two parts of the shaft can slide upon each other and be retained in
any desired position by simple mechanism. Thus the threads of the screw on one
half may precede or follow those on the other half by any regulated distance which
need not exceed half the interval between two adjacent threads of the screw.
this position the divided screw conveyor may be made to rotate as one whole just
as an undivided screw would do.
In
So long as the halves of the screw fit together when set exactly opposite-they
may be mounted on twin shafts working in sleeves of suitable form so that the
halves of the screw can be fixed at regulated positions.
The same method can be applied in the division of a screw conveyor into more
than two parts.
When such a divided screw is mounted inside a tube or cylinder which it fits
accurately it forms on rotating it at a regulated speed the working part of a very
efficient apparatus for the washing or extraction of solid substances by water,
alcohol or other solvents. The solid substance is pushed upwards or forwards by
the rotation of the screw conveyor while the washing liquid or solvent passes in the
opposite direction. Thus the nearly spent material is completely washed or
extracted by meeting with fresh solvent while the nearly saturated solvent meets
with fresh solid substance so that before leaving the apparatus it may be completely
saturated.
An extractor provided with a divided screw as above has the following
advantages:
The washing or solvent liquid can get with equal facility to all parts of the
cylinder containing material-near the centre as well as near the circumference
and edge of the screw.
The rotation of the divided screw secures very perfect mixing of the materials
as the edges of the divided screw cut into the materials in different parts at each
revolution. The rotation also tends to break up any agglutinations or clogging of
the solid materials.

page_text: In working, the solid materials to be extracted are fed into the bottom or lower
end of the apparatus and are then carried upward or forward by the action of
the rotating screw conveyor and at the same time thoroughly mixed by the
action of the divided screw. Finally the spent material issues from the top or
upper part of the cylinder after which it may be pressed dried or treated as may be
desired.
The washing liquid or solvent enters the cylinder of the extractor apparatus at
or near the top or upper end and passes downwards over and through the divided
screw and leaves the extractor at the bottom end charged with the substance
or substances which it is used to dissolve.
In the purification of salts the solid material issuing from the upper end is
frequently the chief object of the operation as for example in the purification of a
mixture of ammonium nitrate containing some sodium nitrate.
The apparatus may be jacketted so as to apply either, heat or cold externally
according to the work required. Thus the apparatus may be used both in the
solution of solids in hot liquids and in the separation of solids as they crystallize
out from hot solutions passing through an apparatus externally cooled.
If necessary, during the working of the apparatus the relative positions of the
parts of the screw may be altered continuously or intermittently, the whole length
of one or both parts of the screw being raked backwards or forwards as may be
desired. Various means may be employed to vary the positions of the screws;
for instance a toothed rack upon one or both of the parts and a toothed wheel or
pinion engaging with one or both and operated in any convenient manner. This
affords a further means of guarding against possible clogging, and of varying the
working of the apparatus.
The rate at which the solid materials are to be pushed upward or forward also
depends on the rate of rotation of the screw. A very slow rate of rotation permits
shorter tubes or cylinders to be used without interfering with the complete
saturation of the solvent used. The adjustment for this purpose must depend on
the materials used.
The rate at which the liquids or solvents pass through the cylinder depends first
on the fineness or character of the materials, secondly on the accuracy of fitting of
the screw inside the cylinder and the degree to which the parts of the divided
screw are separated and thirdly on the height of fall of the liquid in passing
through the cylinder. In order to vary the height of fall of the liquid-so as,
where desirable, to be able to use longer cylinders-the apparatus may be set either
upright or in an inclined position.
In general with these adjustments a single cylinder will be found sufficient for
complete extractions, but several cylinders may be used in series, using right or
left-handed screws as may be necessary.
Dated this 23rd day of January 1896.
BUULI & WADE,
Agents for the Applicant.
Improvements in or relating to Apparatus for Treating and
Extracting Solids with Washing Liquids or Solvents.
I, THOMAS FAIRLEY of 17 East Parade Leeds in the County of York, Chemist,
do hereby declare the nature of this invention and in what inanner.the.same is to be
performed, to be particularly described and ascertained in and by the...following
statement:—
Screw conveyors working in troughs, tubes or cylinders are used for conveying
wet or dry materials in various manufacturing operations. By their means a solid

page_text: material more or less finely divided can be carried upwards or forwards through a
tube or cylinder against a flow of washing liquid or solvent passing in the opposite
direction. With a supply of power to rotate the shaft of the screw conveyor and
proper adjustment of the liquid entering and leaving the apparatus a continuous
extractor may be thus obtained.
My invention relates to a special form of screw conveyor adapted to be
advantageously used in apparatus for the manufacture and purification of certain
salts, for instance, such apparatus is also well adapted for the extraction or
separation of many substances from mixtures by means of water, alcohol or other
liquid solvents.
The improved form of screw apparatus may be described, as, in its simplest
form derived from an ordinary screw conveyor by dividing it along a section
passing lengthwise through the axis of the shaft of the screw into two equal and
similar parts. If now the free ends of the divided shaft be fitted with sleeves
passing over them the two parts of the shaft can slide upon each other and be
retained in any desired position by simple mechanism.
Thus the threads of the screw on one half may precede or follow those on the
other half by any regulated distance which need not exceed half the interval
between two adjacent threads of the screw. In this position the divided screw
conveyor may be made to rotate as one whole just as an undivided screw
would do.
So long as the halves of the screw fit together when set exactly opposite-they
may he mounted on twin shafts working in sleeves of suitable form so that the
halves of the screw can be fixed at regulated distances.
The same method can be applied in the division of a screw conveyor into more
than two parts.
When such a divided screw is mounted inside a tube or cylinder which it fits
accurately it forms on rotating it at a regulated speed the working. part of a very
efficient apparatus for the washing or extraction of solid substances by water
alcohol or other solvents. The solid substance is pushed upwards or forwards by
the rotation of the screw conveyor while the washing liquid or solvent passes in
the opposite direction. Thus the nearly spent material is completely washed or
extracted by meeting with fresh solvent while the nearly saturated solvent meets
with fresh solid substance so that before leaving the apparatus it may be completely
saturated.
An extractor provided with a divided screw as above has the following
advantages:-
The washing liquid or solvent can get with equal facility to all parts of the
cylinder containing material-near the centre as well as near the circumference
and edge of the screw.
The rotation of the divided screw secures very perfect mixing of the materials
as the edges of the divided screw cut into the materials in different parts at each
revolution. The rotation also tends to break up any agglutinations or clogging of
the solid materials.
In working the solid materials to be extracted are fed into the bottom or lower
end of the apparatus and are then carried forward or upward by the action of the
rotating screw conveyor and at the same time thoroughly mixed by the action of
the divided screw. Finally the spent material issues from the top or upper part
of the cylinder after which it may be pressed dried or treated as may be desired.
The washing liquid or solvent enters the cylinder of the extractor apparatus at
or near the upper end and passes downwards over and through the divided screw
and leaves the extractor at the bottom end charged with the substance or substances
which it is required to dissolve.
In the preparation of salts the solid material issuing from the upper end is
frequently the chief object of the operation as for example in the purification of a
mixture of ammonium nitrate containing some sodium nitrate.
The apparatus may be jacketted so as to apply either heat or cold externally

page_text: according to the work required. Thus the apparatus may be used both in the
solution of solids in bot liquids and in the separation of solids as they crystallise
In this
out from hot liquids passing through an apparatus externally cooled.
latter case it may be convenient to supply the liquid towards the lower end of
the apparatus.
If necessary during the working of the apparatus the relative positions of the
parts of the screw may be altered continuously or intermittently-the whole length
of one or both parts of the screw being raked backwards and forwards as may be
desired. This affords a further means of guarding against possible clogging and
of varying the working of the. apparatus. Various means may be employed to
adjust or alter the positions of the parts of the screw-such as a toothed rack on
one or both the halves engaging with a toothed wheel or pinion. The following
gives a firm and accurate adjustment which can be varied without stopping the
working:-
The divided axis can be made hollow so as to enclose a smaller rod screwed
and fitting into screwed parts projecting on the inner side of one of the halves of
the divided axis. This central rod is held by bearings from the inner side of the
other half of the axis-and it projects outside beyond the axis-so that it can be
turned and shifted.
The rate at which the solid materials are pushed forward depends on the pitch
and rate of rotation of the screw.. Within practicable limits a slower rate of
rotation permits shorter cylinders to be used-still securing complete saturation of
the solvent employed. The adjustment for this purpose must depend on the nature
of the materials.
The rate at which the liquids pass through the cylinder depend on :-First the
fineness or character of the materials: second on the accuracy of fitting of the
screw inside the cylinder and the degree to which the parts of the divided screw
are separated; and third on the vertical height of the fall of the liquid in the
cylinder. This fall may be varied according as the apparatus is set upright or in
an inclined position.
In general with these adjustments one cylinder may be found sufficient for
complete extractions-but several cylinders may be used in series using right or
left handed screws as may be necessary.
The accompanying figure is a view partly in section and partly in elevation of
A is the divided
part of an extraction apparatus containing the divided screw.
screw and shaft the line A' indicating the division. B is the cylinder enclosing it.
The liquid enters at C and flows through the cylinder and material and out at D
charged with the substance to be extracted. The solid substance enters at E and
after being treated leaves the cylinder at F.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In apparatus for treating solids with liquids a screw divided longitudinally
substantially as described.
2. In apparatus for treating solids with liquids a divided screw of the kind described
the divisions of which are movable end wise.
3. In apparatus for treating solids with liquids a divided screw of the kind
described the divisions of which are moved endwise during the treatment.
4. In apparatus for treating solids with liquids the combination of divided screw
such as A and circular casing B with or without inlets and outlets C D E F..
THOMAS FAIRLEI.
Boult & Wade,
Agents for the Applicant.
Dared L
DRE
OOCLONCE
THOMAS FAIRLEI.
Boult & Wade,
Agents for the Applicant.