Improvements in or Appertaining to the Sieving, Separating, or Purifying of Granular, Pulverulent, or other like Material.
Year: 1889

page_text: Date of Application, 12th Aug., 1889
Complete Specification Left, 17th Apr., 1890-Accepted, 7th June, 1890
PROVISIONAL SPECIFICATION.
Improvements in or Appertaining to the Sieving, Separating, or
Purifying of Granular, Pulverulent, or other like Material.
I, JAMES HIGGINBOTTOM of 32 Seel Street, Liverpool in the County of Lancaster,
Milling Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates broadly to the sieving, separating, or purifying of granular,
pulverulent or other like material.
The invention is specially applicable to the separation of impurities such as bran,
cellulose, or the like from semolina, middlings, dunst, flour, or similar material, and it
is intended to be mainly applied to the vibrating sieves of purifiers, such as are
employed in flour mills, etcetera.
It is well known to millers that the besi separation of the impurities, or in other
words the best purification of the material is effected when the surface of the vibrating
sieve of a purifier is kept covered to a sufficient depth by the material under treatment,
also that in ordinary practice it is difficult to maintain a sufficient depth all over the
sieve from head to tail, except by carrying a large feed and by allowing a large
proportion of such feed to be discharged over the tail of the sieve; thus rendering it
necessary to re-treat the material which has passed over the tail of the sieve.
Now my invention enables the layer of the material on the sieve to be kept at any
desired thickness over any portion of the sieve surface, as it is travelling over the
same towards the tail thereof, and this is accomplished without the necessity of
allowing a large proportion of such material to pass over the tail of the sieve.
In carrying out my invention I place ribs, either fixed or adjustable, at intervals
across the sieve surface thus forming a series of sieve surface spaces having a rib
between each space, the top edges or faces of such ribs being fixed at such a height
above the sieve surface as will cause the surface of the sieve between each two ribs
to become covered to the desired depth by the material passing over the sieve
surface.
I prefer to make these ribs with sloping sides on their upper faces, so as to facilitate
the passage of the material over the top of the ribs-from space to space.
The ribs keep the sieve surface constantly covered with material to the desired
depth. The vibratory motion of the sieve and the action of the uprising air current
conjointly cause the particles which are of less specific gravity to accumulate near
the top of the material on the sieve, so that such particles do not come into actual
contact with the sieve surface. Under these conditions there results, as is well under-
stood by millers, a much better purification of the material than could have been
obtained in a case where, through deficiency of feed, the layer of material under
treatment is so thin that the heavier particles quickly pass through the sieve and
bring the lighter material into actual contact with the surface of the same. Also,
with a sieve provided with ribs as above described, any desired depth of material on
the sieve surface may be obtained, without the necessity of providing such a heavy
feed that a portion of the material is discharged unpurified into the tails.
Although the invention has been described mainly in reference to the sieves of
purifiers for flour, dunst, middlings, semolina, or the like, yet I wish it to be under-
stood that it is applicable to almost any other kind of sieving or sifting machinery,
where the material is passed during treatment over a horizontal or slightly inclined
vibratory sieving surface, which is under the action of an uprising current of air or
other fluid.
Dated this 10th day of Aumunt 1000

page_text: COMPLETE SPECIFICATION.
Improvements in or Appertaining to the Sieving, Separating, or
Purifying of Granular, Pulverulent, or other like Material.
I, JAMES HIGGINBOTTOM of 32, Seel Street, Liverpool in the County of Lancaster,
Milling Engineer, do hereby declare the nature of this invention and in what
imanner the same is to be performed, to be particularly described and ascertained in
and by the following statement:-
This invention relates to certain improvements in the method of and apparatus for
sieving, separating or purifying granular, pulverulent or other like material, in cases
where such material is passed, during treatment, over a horizontal or inclined
vibratory sieving surface which is under the action of an uprising current of air
or other fluid. The invention is especially applicable to the separating of bran,
cellulose or the like from semolina, middlings, dunst and flour.
In sieving or purifying machinery of the above description, it is well known to
millers that the best separation of the impurities, or, in other words, the best
purification of the material, is effected when the surface of the vibrating sieve is kept
covered to a sufficient depth by the material under treatment. In other words, a
sufficient depth of good material must be passed or maintained over all the sieve
surface, so as to keep the impurities floating or suspended near the top of the same or
out of contact with the sieve surface. It is also well known that in ordinary practice
it is difficult to maintain a sufficient depth all over the sieve from head to tail,
except by carrying a large feed and by allowing a large proportion of the particles
of good material in such feed to be discharged over the tail of the sieve, thus rendering
it necessary to re-treat the material which has passed over the said tail.
Attempts have been made to maintain the desired depth of material on the sieve
from head to tail, and, in some instances, millers have used a device for automatically
returning a portion of the "tails" to the bead of the machine, but this method has
proved a failure in practice, because the feed rapidly accumulates and prevents the
proper purification of the material.
-
Now my invention enables the layer of the material on the sieve to be kept at
any desired thickness, over any portion of the sieve surface, as the material is
travelling over the same towards the tail thereof, and this is accomplished without
the necessity of allowing a large proportion of the good material to pass over the
tail of the sieve.
The invention may be described by reference to the accompanying drawing, in
which,
Figures 1 and 2 are longitudinal sections through a portion of the sieve, showing
two slightly modified forms of my improvement.
A is the horizontal or slightly inclined sieve which is vibrated by any suitable means
in snch a manner that the material is caused to travel over its surface in the direction
indicated by the arrow B. At the same time a current of air passes upward through
the sieve and material, in the well known manner, as shown by the arrows C.
In carrying the invention into effect, I place ribs F, either fixed or adjustable,
at intervals across the sieve surface, thus forming a series of sieve surface spaces G
having a rib F between each two adjacent spaces, the top edges or faces of such
ribs being fixed at such a height above the sieve surface, having regard to their pitch
and the inclination, if any, of the sieve, as will cause the surface of the sieve
between each two successive ribs to be covered to the desired depth by the material
passing, over the said surface..
"I prefer to make the ribs F of a sloping or curved form on their upper.faces
so as to facilitate the passage of the material over the top of the ribs from space,
to space, as seen in Figures I and 2.
When the sieve covering is formed of silk or other textile material, it is preferable
to make the ribs of cord or, stout wire as.in Figure 1, and to stitch or bind them
to the covering, but when the sieve covering is of metal, as in Figure 2, the ribs
1.

page_text: may be also made of metal and soldered to the covering, or otherwise secured
thereto.
The ribs keep the sieve surface constantly covered with material to the desired
depth, and the vibratory motion of the sieve and the action of the uprising air
current conjointly cause the particles, which are of a less specific gravity, to
accumulate near the top of the material on the sieve-so that such particles do
not come into actual contact with the sieve surface. Under these conditions, there
results, as is well understood by millers, a better purification of the material than
could have been obtained in a case where, through deficiency of feed, the layer of
material under treatment is so thin that the heavier particles quickly pass through the
sieve and bring the lighter material into actual contact with the surface of the
same. Also, with a sieve provided with ribs, as above described, any desired depth
of material on the sieve surface may be obtained, without the necessity of providing
such a heavy feed that a portion of the good material is discharged into the tails.
It will also be seen that, however small may be the rate at which the feed is admitted to
the purifier, the ribbed sieve can be arranged with meshes of such a coarseness as
to allow a minimum quantity of the material to pass over the tails, and, at the
same time, the ribs keep all the spaces G full of material, because, if any particles
of the material are too large to pass through any of the meshes of the sieve, such
particles fill up the spaces between the ribs before they can pass over the tail of
the sieve, and thereby the sieve surface is covered with the material to any desired
depth.
Although the invention has been described mainly in reference to the sieves of
purifiers for flour, dunst, middlings, semolina, or the like, yet I wish it to be
understood that it is applicable to almost any other kind of sieving or sifting
machinery, where the material is passed during treatment over a horizontal or
slightly inclined vibratory sieving surface, which is under the action of an uprising
current of air or other fluid.
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 :-
In a machine for sieving, separating or purifying granular, pulverulent or other
like material, the combination, of a horizontal or slightly inclined vibratory sieve
having its upper surface divided into a series of separate sieving spaces of suitable
depth, by means of a series of ribs arranged transversely thereon, with an uprising air
current through the sieve, whereby the material on the sieve is maintained under the
uprising air current at a sufficient depth, without the necessity of passing a large
proportion of good material over the tail of the sieve, substantially as described.
Dated this 16th day of April 1800.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, and London, Patent Agents.