Improvements in Machines for Separating and Sorting Granular and Pulverulent Materials.
Year: 1893

page_text: Date of Application, 3rd July, 1893
Complete Specification Left, 30th Mar., 1894-Accepted, 5th May, 1894
PROVISIONAL SPECIFICATION.
Improvements in Machines for Separating and Sorting Granular and
Pulverulent Materials.
I, GEORGE FREDERICK THOMPSON of 29 Newstead Road Liverpool in the
County of Lancaster, Mechanical Engineer do hereby declare the nature of this
invention to be as follows:-
My invention relates to certain improvements in machines used for separating
and sorting by sieving and the application of air currents-granular and
pulverulent or granulated materials or substances such as wheat or other grain or
cereal, pulse etc., either whole or in a broken or granulated state; also for other
substances or materials capable of being separated and sorted by sieving and
subjection to the influence of a current or currents of air for the purpose of
separating the small from the larger and the light from the heavier particles
thereof.
The leading feature of my said invention consists in the employment of endless
bands or webs of suitable size and construction as the sieving surfaces or media in
place of the usual forms of sieve, stretched or otherwise held within fixed or
movable frames.
The said endless bands or webs may consist of a series of bars of iron or other
material attached to two or more endless bands or chains; of woven wire; of thin
perforated sheet metal or other suitable flexible material; or of woven silk, cotton
or other fibrous material.
The aforesaid bands or webs are carried by two or more rollers and are caused
to travel slowly in one direction; one of the said rollers being capable of adjustment
for the purpose of stretching and tightening the said webs.
The material to be sifted or sorted is spread in a thin layer upon the said band
or web as it passes along, and at one or more points between the carrying rollers I
impart to the said band, by suitable mechanism, a quick vibratory motion
transversely to the direction in which the band is travelling for the purpose of
agitating the material thereon and setting up a sieving action. Those particles of
material which are too large to pass through the apertures or interstices of the
said web are carried along thereby and eventually fall off as it passes around the
roller.
Currents of air, set up by a fan or other means, guided by suitable ducts are
drawn upwards through the said bands or webs, and the material thereon, at
certain points, for the purpose of lifting out of and carrying away from the said
material any light substances or particles which the said currents of air according
to their intensity are calculated and regulated to withdraw. Such particles are
afterwards trapped
or intercepted by causing the air to pass through suitable
catch boxes or chambers for the purpose.
Dated this 20th day of June 1893.

page_text: Improvements in Machines for Separating and Sorting Granular and
Pulverulent Materials.
I, GEORGE FREDERICK THOMPSON of 29 Newstead Road, Liverpool in the
County of Lancaster, Mechanical Engineer, 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 :-
My invention relates to certain improvements in machines used for separating
and sorting--by sieving and the application of air currents-granular and
pulverulent or granulated materials or substances such as wheat or other grain or
cereal, pulse etc., either whole er in a broken or granulated state; also for other
substances or materials capable of being separated and sorted by sieving and
subjection to the influence of a current or currents of air, for the purpose of
separating the smaller from the larger, and the lighter from the heavier particles
thereof.
The leading features of my said invention consist in the employment of an
endless travelling band or web of suitable size as the sieving surface or medium,
and imparting thereto a quick vibratory motion transversely to the direction in
which the said band travels, in place of the usual forms of sieving media; and the
method of directing and concentrating the air current or currents employed.
The objects of iny said invention are, (1) by providing a constantly changing
sieving surface to allow of the part not in use as a sieving medium, being cleaned
and prepared for receiving the feed and so insure a constant and regular grading
or separating of the material treated; (2) to provide a ready means for varying
the area of the interstices of the sieve surface; and further, by providing ducts
both beneath and above the sieving medium to direct and concentrate the air
current or currents employed and so obtain the best results therefrom.
My said band or web may consist of (1) transverse bars or rods of metal or other
material attached to two or more endless bands or chains; (2) transverse wires
interwoven with strands of flexible material; (3) of perforated sheet metal,
parchment or other suitable flexible material; (4) of woven wire, silk, cotton or
other fibrous material.
The aforesaid band or web is carried upon two or more rollers and is caused to
travel slowly in one direction; one of the said rollers being capable of adjustment
for the purpose of stretching and for tightening the said band longitudinally,
The material to be sifted or sorted is spread in a thin layer upon the said band
or web as it moves along and at one or more points between the said carrying rolls
a quick vibratory motion is imparted, by suitable mechanism, to the said band
transversely to the direction in which it is travelling, for the purpose of agitating
the material thereon and setting up a sieving action. Those particles of material
which are too large to pass through the interstices of the said band or web are
carried along thereby and eventually fall or are brushed off as it passes around
the roller.
Air is drawn by means of a fan, or other apparatus, in an upward current
through the said web for the purpose of lifting out & carrying away, from the
material thereon, any light substances or particles which the said current of air is
calculated or regulated to withdraw, and the said current of air is divided into
streams guided and concentrated at certain points in the length of the said band
by means of guide-boards, V or other shaped troughs or blocks placed immediately
beneath, and deep V-shaped troughs with deflecting sides placed above the band
in similar positions to the troughs or blocks beneath same for the purpose of
guiding and maintaining the intensity of the upward currents, and receiving the
material raised by the air. Triangular-shaped blocks are placed between the said

page_text: troughs forming, in combination therewith, secondary or return passages to allow
of any heavy material raised by the said air current or currents falling back again
upon the sieve at points over the troughs or blocks beneath.
When the said bands are of the fourth construction already named they are
furnished with thickened edges or bindings of elastic or non-elastic material which
are carried in suitable grooves. The grooved pieces at one or both sides being
adjustable for the purpose of tightening the web transversely.
When my said bands or webs are made as above, i.e. of woven wire, silk, cotton
or other suitable material I employ the said material in two ways, (1) with the
strands or "warp" and "weft" longitudinal and transversely, respectively, or
(2) diagonally, to the edges of the said web. In the former case the thickened
edges or bindings are of non-elastic material such as cotton, hemp or other cord, or
strips of leather or other suitable flexible material. In the latter case the said
thickened edges or bindings are formed of elastic material such as rubber cord, small
helices of wire, or other suitable material or combination of an elastic nature. The
reason for this formation is to allow of the said web being stretched longitudinally
or transversely which, when the strands or warp and weft are diagonal to the
direction in which the material is drawn or stretched, has the effect of closing the
meshes in one direction and thus reducing the area of the interstices. By arranging
the said grooved side-pieces, in which the thickened edges are carried, out of parallel
with each other and causing the said web to become widened or narrowed as it
travels along I obtain a gradual enlarging or reducing of the said meshes for
the purpose of allowing more or less material to pass through the said band
or web.
At the point or points where the band is to receive the vibratory motion, short
sections of the grooved pieces at each side are loose and are attached together in the
form of a frame to which is given the aforesaid motion.
Figs. 1 and 2 upon the sheet of drawings appended hereunto represent transverse
and longitudinal sections respectively of a machine constructed in accordance with
my said invention in which A. A. is the said travelling band sieve having thickened
edges A¹ A¹, carried by rollers B. B', motion being given to same by means of the
worm & wheel R. H. H. are the grooved pieces for carrying & guiding the
thickened edges of the said band.
Material to be treated is fed on to the band by the hopper T. C. C. C. C. are
the V-shaped troughs or guides of wood or other material placed beneath the band,
and D. D. D. are the troughs above same constructed of tin or other suitable
material. E. E. E. are the triangular blocks forming, with the said troughs, the
return passages F. F. F. The troughs D. D. D. have false bottoms slanting in each
direction from the centre as shewn in Fig. 1 and the material deposited in same
runs down into the spaces G. G. from whence it may be removed by scrapers or
other means.
This form of trough is a known device and I do not claim it as novel, but the
formation of return passages by the combination with a cross trough a triangular
block is new to the best of my knowledge.
In that portion of the band where no troughs are shewn, are placed the loose
grooved pieces to which the vibratory motion is imparted by means of an eccentric I
upon the fan spindle K and the connecting rods and bell-crank shewn, or other
means may be employed. Primary motion being received by the pulley S.
Air is drawn upwards through the said band by means of the fan P and the
intensity of the draught at either side of the central partition is regulated by the
valves Q. Q.
The material falling through the band is guided over the under or return side of
the band by means of the roof or shedding plates L. L. and falls into the hopper
beneath where it may be drawn to one end by a screw conveyor such as M.
Material carried over is received in the space N.
I do not confine myself to the employment of one travelling band or web only, I
may employ and combine two or more in one machine either placed alongside oue

page_text: another, one above another all running longitudinally, or placed above one another,
one or two running longitudinally and the other transversely or vice versa.
Nor do I confine myself precisely to the formation and arrangement of the troughs
or ducts above and beneath the said band, I may place one or more over that
portion to which is given vibratory motion and connect them to a chamber or
chambers formed to trap and collect the material raised thereto by the air current
or currents.
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. In machines for separating and sorting granular and pulverulent materials or
substances, the employment of an endless travelling grid, web or band as the sieving
medium, to which is imparted at one or more points a quick vibratory motion
transversely to the direction in which the said web is travelling, substantially as
herein shewn and described.
2. The formation of an endless band or web sieve constructed of woven wire,
fibrous or other material having the strands of same arranged diagonally to the edges
of the said band or web and the combination therewith of elastic bindings or thickened
edges, substantially as herein described and for the purpose stated.
3. The combination with a band or web sieve, having elastic bindings or
thickened edges, of the grooved pieces H and the method of setting them
at an angle to each other substantially as herein described and for the purpose
stated.
4. The combination with a travelling grid, band or web sieve of one or more air
ducts below the said web formed by guide plates, troughs or blocks for the purpose
of guiding and concentrating in one or more places the air employed, substantially
as herein shewn and described.
5. The combination with a travelling grid, band or web sieve of one or more air
ducts formed by troughs, blocks or guide plates above the said web corresponding
and in combination with the aforesaid ducts beneath, substantially as herein shewn
and described, and for the purpose stated.
6. In machines for separating and sorting granular and pulverulent materials by
means of sieving surfaces and air currents, the combination with transverse V-shaped
troughs or blocks, of the triangular blocks E for the purpose of forming return
passages, and the combination therewith of the corresponding blocks or troughs
placed beneath the sieving medium, substantially as herein shewn and described.
Dated this 29th day of March 1894.
GEORGE FREDERICK THOMPSON.