Improvements in Plane Sieves used in Flour-mills and the like.
Year: 1894

page_text: Date of Application, 14th Dec., 1894
Complete Specification Left. 20th July, 1895-Accepted, 24th Aug., 1895
TROYEDIONAU
[Communicated from abroad by EMILE PICARD, of 14 Rue du Trône, Brussels, in
the Kingdom of Belgium, Engineer.]
Improvements in Plane Sieves used in Flour-mills and the like.
I WILLIAM PHILLIPS THOMPSON F.C.S. M.I.M.E. of The Agency for
Foreign Patent Solicitors 31 High Holborn in the County of Middlesex, 6 Lord
Street Liverpool and 6 Bank Street Manchester both in the County of Lancaster
and Lower Temple Street Birmingham in the County of Warwick Civil Engineer
do hereby declare the nature of this invention to be as follows:-
This present invention relates to "plansichters" or plane sieves having a circular
or elliptic rotary motion, whether in the case of sifting or bolting sieves, or in the
case of collecting trays or bottom sieves for collecting the sifted matter, and it
has for its object a single, special and new mechanism which permits, by a sole
movement, the matter to be sifted to advance and the meshes of the sifting tissue
to keep quite open and the collecting bottoms of the sieves free from any
obstruction, and consequently to suppress the "putzgut or cleaning or rebounding
matters which are actually used for this object, and also the apparatuses serving to
bring these "putzgut" back to their original position.
"
It is well known that in order to advance the matter to be sifted in plansichters,
it is necessary to stop, at a certain point, this matter to be sifted in its rotary
back-motion in order to make it produce a new advancing spiral starting from its
point of stoppage.
According to this invention, I make use of moveable obstacles which only
present themselves momentarily, but at the proper time, before the matter to be
sifted when this latter must be stopped in its back motion, but which move
completely out of contact with this matter to be sifted when they are no longer
needed to stop this back motion.
These obstacles or advancing apparatuses themselves communicate to the sifting
tissue or to the collecting bottom, the necessary vibrations which prevent their
obstruction and which permit the suppression of the several independent bodies
actually used for producing those vibrations.
The principle of my invention consists in the use of these guided moveable
bodies set in motion by the plansichter itself so as to present to the matter to be
sifted a temporary obstacle at the very moment when this matter is urged
backwards, and getting quite out of the way when, by the motion of the plansichter
it is urged forwards; these guided bodies serving moreover, in consequence of the
shocks produced, to keep open the meshes of the sifting tissue and the bottom of
the sieve free from any obstruction.
This invention can be performed in
all based upon
the same
principle which I have just above set forth.
The advancing of cleaning moveable obstacles may be made of wood, iron,
hardened leather, ebonite or any other convenient matter; they move transversely
across the channels of the plansichters; this motion is oblique, but it could also be
parallel or curvilineal with respect to the plane of the sieve or to that of the
Lottom carrier.
many
different
ways
These moveable bodies may rest upon guides or in grooves of any kind, they
may be traversed by these guides or be guided by straps fixed in any convenient.
Away. so as to be guided into the path they have to move in.

page_text: These bodies may carry at their lower. side asperities or projections of any kind
such as little boards straight or inclined; brushes, etc., they may carry brushes at
their upper side so as to brush the under part of the sifting tissue of the upper
sieve; they may also carry strings of. silk or depending threads constantly moving
upon the sifting tissue; they may lastly consist of cylindrical brushes rolling
upon the bottom of the sieve and they may even fill up all the space between both
sieves.
'
As examples: From one of the side walls of the frame to the other, are
arranged a series of guides more or less separated and starting from an elevated
point of one of these walls to join at a point of the opposite wall near the sifting
tissue.
Upon these parallel.guides.moves a little, board-or several little boards disposed
end to end in the length of the channel-constituting the moveable obstacle and
imparting to the frame the necessary vibrations...
The surface of these little boards is smooth; nevertheless they could be slightly
corrugated. at their underside or carry any kind..of projections or asperities such.
as little boards placed, transversely or. obliquely, brushes,, indentations, etc.,, they
may be of the same length on nearly, the same length as the channel, but they, are
narrower than its breadth; if there be but one in the channel,.it is guided by the
exterior sides of the frame; if there are several placed. end to end, they are guided
by a small crossbar conveniently located to this effect.
In the described arrangement, there is no return. channel for the matter to be
sifted; but it. is obvious that if such a return channel is needed, it will be necessary
to place at one end of two contiguous channels a, little board upon inclined guides
transversely disposed.
At every rotary motion of the sieve, the little boards are urged, together with
the matter to be sifted at the inferior part of the guides, against the vertical wall.
of the sieve, where, by a single pressure upon the matter to be sifted, or on account
of the projections or asperities which they carry at their lower side, they stop
during one instant the matter to be sifted; then the rotary motion continuing the
little boards are urged against the opposite wall of the frame at the upper part of
the inclined guides leaving quite clear all the surface of the sifting tissue. The
shocks produced by the little board during this alternate motion against the walls
of the sieve communicate to the sifting tissue or to the collecting bottom, the
necessary vibrations to keep open the meshes or to prevent any obstruction..
The little board may also be provided with a heel at its lower side which, when
the little board ascends upon its guides comes into contact, with a support fixed
upon the bottom of the sieve and lifts up the little board so as to make it assume
a horizontal position when it arrives-at the end of its stroke. During this movement
the little board shakes the sifting tissue that lies above and disengages the meshes
from all the flour that sticks to them.
The little board that moves in the collecting frame under the sifting tissue of
the upper sieve may be fixed. by its upper end to a piece of canvas the other end
of which is fixed at the upper side of the opposite wall of the frame. This canvas
must have wide open meshes so as to leave free passage to the sifted matter coming
from the upper sieve. During the alternate motion of the little board, this canvas
which is a few millimetres shorter than the width of the frame, stretches when the
little board ascends, and slackens when the board' descends. At every stroke,
when the canvas is stretched it rubs the under side of the sifting tissue and, frees
it from any obstruction.
The guides may be replaced by suspension ropes which may be of leather, catgut
or any other suitable straps. These straps which. are fastened to the upper part
of one of the frame walls retain, when at rest, the little board in a position
parallel to the plane of the sieve; but permit it during the rotary motion of the
plansichter, to be lifted up by the centrifugal force.
As before stated, the little board may be smooth or it may carry at its lower side
corrugations or projections in order to stop the matter to be sifted when, by the

page_text: plansichter's motion, it is urged backwards; but immediately after, the little board
is lifted up out of the way and the matter to be sifted can pass freely.
The little board may also be provided at its lower side with projections and move
transversely upon guides placed horizontally according to the plane of the sieve.
At every movement of this latter, the little board is urged against one of the
vertical walls and stops the matter to be sifted at the very moment it has to be
stopped; then it is urged against the opposite wall leaving quite free the surface
upon which the matter to be sifted is travelling.
Dated this 14th day of December 1894.
W. P. THOMPSON & Co:,
Agents for the Applicant.
Improvements in Plane Sieves used in Flour-mills and the like.
I, WILLIAM PHILLIPS THOMPSON, F:C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 31, High Holborn, in the County of Middlesex,
6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in the County
of Lancaster, and Lower Temple Street, Birmingham, in the County of Warwick,
Civil 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:-
It is a well-known fact, that in the case of plane sieves, or so-called. "plan-
sichters" receiving a rotatory motion in a horizontal plane, the material which is
to be sifted, in order to move ahead in the different channels of the sieve has
to be checked, or as it were have a skid put on, whenever the sieve is moving
through the backward part of its course, and has to be freed again, when the sieve
enters the forward part of its course. Without this precaution the material to be
sifted would keep turning round and round without advancing. Besides this, with
the sieves in question as well as with all other sieves, care must be taken to keep
the meshes of the sifting gauze free from obstructions, which is accomplished
in the easiest way by frequent knocks, either against the sifting surface itself, or
against the frame of the sieve, the result of which knocks is to continually shake
the sifting surface.
The object of the present invention is to realise both these effects at the same
time by means of a single device.
This device is shewn in its simplest form in the annexed drawings, Fig. 1 being
a horizontal projection of a plane sieve provided with such device, Fig. 2 being a
transversal section through line X-X of Fig. 1, and Fig. 3 a longitudinal section
through line Y-Y of Fig. 1.
In the several figures of the drawings, the same letters refer to the same parts.
The substance of the invention is embodied in battens, acting brake-fashion, and
disposed in the different channels in such a way, that they are obliged, under the
influence of centrifugal force to move along oblique guides alternately down
towards the material to be sifted, and upwards away from the same.
These same battens are used for giving to the sifting gauze the necessary
vibrations to keep its meshes free from obstructions, which is accomplished by the
battens continually knocking against the frame of the sieve.
A is the frame of a plane sieve.
B the sifting gauze.
C are the oblique guides, and
D the battens used in the same time for checking the material to be sifted, and
for keeping the sifting gauze free from obstructions.
These battens D may be made of wood, iron or any other suitable material;

page_text: they may consist of one single piece, occupying the whole length of the channel, as
shewn in the first compartment to the left of Fig. 1 and 2, or there may be more
than one, square or round, arranged in sets, as shewn in the second compartment of
Fig. 1 & 2 (reckoning from left to right); or in case of a heavier batten being
required; it may be made wider, as if two or three narrower ones had been joined
into a single one, as shewn in the third compartment of Fig. 1 and 2; or this wide
batten may be hollowed out, in order to have a large batten without too much
weight, as shewu in the fourth compartment of Fig. 1 and 2. The battens may
also be roughened on their under side, in order to better ensure their checking or
braking effect upon the material to be sifted.
The guides C stretch from a point near the upper edge of one of the long sides
of the channel to the vicinity of the lower edge of the opposite long side, but there
is no necessity for the battens D coursing all this way across the whole width of
the channel. The guides C, as shewn in the first and third compartments of Fig. 2,
may be provided with cleats E, which will limit the upward course of the battens,
while blocks fixed against the opposite long side of the channel will transfer to
the frame, and consequently to the gauze, the vibrations which they receive
through the battens beating against them. It is evident that the obliquity of the
guides C must be directed in such a way, that the battens will be below, and
acting upon the material which is to be sifted, when the corresponding part of the
sieve is in that part of the circular course, where the material has to be acted upon,
and that these same battens will be jerked upwards, when the material has to be
freed from its impediments.
In case of the material being required to pass from one channel into the next
one, a batten, or a set of battens may be disposed in the cross-channel, connecting
the two main-channels, but of course in the direction of this cross-channel, as shewn
in the right-side half of Fig. 1, and at the lower end of Fig. 3.
Finally I wish to say that although I prefer to use oblique guides C, I might
nstead use horizontal guides, obtaining a similar, but less perfect result.
Having now particularly described my invention and in what manner the same
is to be performed, I declare that what I claim and desire to secure by Letters
Patent, is
In a plane sieve divided into longitudinal channels, and having a rotatory
motion, a single device for moving the material ahead in the channels, by checking
it at the moment when it tends to turn back, and freeing it, when it is required
to move ahead, and for keeping the meshes of the sifting gauze free, by vibrations
imparted to the frame, both duties being performed by battens D, coursing freely
up and down oblique or horizontal guides C, in order to check the material, which
is to be sifted, at the proper moment, and to free it again, when the rotatory motion
is apt to move it ahead, while the repeated knocks of the battens against the
frame A of the sieve, or against properly adapted cleats E and blocks v, continually
shake the sifting surface B, by which means the meshes are kept open, substantially
as described, and shewn in the drawings.
Dated this 20th day of July 1895
W. P. THOMPSON & Co.,
31, High Holborn, London, W.C., Patent Agents for the Applicant.