Improvements in Apparatus for Sifting or Screening Flour and other Materials.
Year: 1889

page_text: Date of Application, 19th Mar., 1889
Specification Accepted. 18th May, 1889
COMPLETE SPECIFICATION.
Improvements in Apparatus for Sifting or Screening Flour and
other Materials.
I, HEINRICH SECK, of Leubnitzerstrasse 15, Dresden, in the Kingdom of Saxony
and German Empire, Manufacturer, 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:-
1
My invention relates to sifting and screening apparatus of the kind in which the
sieve is subjected either to a rocking or a reciprocating or rotary motion.
In sifting apparatus of this kind it is essential that the flour or other material to be
sifted should be distributed over the surface of the moving or reciprocating sieve in as
thin a layer as possible and that it should be conveyed across the said sifting surface
with a positive movement in a regular and controllable manner, and at the same ti ne -
be turned over regularly and energetically and spread out on the sifting surface so
that the parts of greater specific gravity such as flour will always be in contact with
the bolting silk whilst the lighter bran is conducted to the upper surface of the layer
of material to be sifted.
It has been found in practice that none of the arrangements of flat sieves of this
tyre as heretofore constructed have answered the above mentioned requirements so
as to give good results.
My said invention comprises a novel arrangement of a sifting apparatus by which
complete results are obtained and in which a continual spreading out and turning over
of the flour or other material to be sifted is effected, the said results being moreover
obtained with the sieve in a horizontal or inclined position the said sieve having a ·
horizontally reciprocating or a rotary motion imparted thereto.
In the accompanying drawing.
Figure 1 is a vertical longitudinal section of the improved sifting apparatus.
Figure 2 is a similar view to Figure 1.
Figure 3 is a sectional plan taken on the line of Figure 1.
Figure 4 shows several sieves arranged side by side in a single frame.

page_text: In the drawing the sieve is supposed to be subjected to a reciprocating motion and
to be arranged as a whole in a horizontal plane.
A is the main frame of the apparatus, b'is the reciprocating frame which carries the
sieves proper d. The said reciprocating frame is attached to the main frame by
links a.
Motion is imparted to the said frame from any suitable motor or source of
power by means of the pulley A' attached to a crank shaft A² supported in bearings
on the main frame A, and by a connecting rod A³ having one end attached to the
crank shaft and the other journalled in a bracket on the frame b.
The sieve d is formed by a number or series of sections arranged in succession,
each of said sections being inclined upward preferably in the direction from the inlet
towards the outlet and connected with the adjacent section in front thereof by a sharp
angle so as to form a sharp-edged wall or step e which during the movement of the
sieve in one direction will act to retain or stop the movement of the flour or other
material, whilst during the movement of the sieve in the opposite direction the said
step will act upon the said material to propel the same forward.
As will be seen from the vertical longitudinal section Figure 1 the material to be
sifted enters upon the rearmost sieve section at f. The position of the crank in
Figure shows the sieve d as just having completed half its stroke in a backward
direction and corresponding therewith the material is shown as just in the act of
jumping over from one sieve-section to the adjacent section in front thereof.
In the sectional view Figure 3 the crank is shown as having just completed its
backward stroke and assumed its dead centre. The material thrown forward by the
backward stroke from one sieve-section rests for an instant on the sifting surface when
the crank is at the said dead centre.
The crank will now start in its forward movement which will cause the material to
be thrown backwards until it strikes violently against the several steps c, as illustrated
in the longitudinal section Figure 2 which represents the crank at its forward dead
centre. The effect of the steps c is to prevent the material from re-entering upon the
sieve-section on which it was resting during the preceding part of the revolution of
the crank, the said steps forming a rebounding wall for the moving material which
will strike or bounce against said wall in a manner similar to the waves of the sea
striking a steep coast, so as to be interrupted in its movement and thrown over.
In the return movement the sieve will be operated as described with reference to
Figure 1 and the material will be thrown forward again upon another sieve-section
whereupon it is thrown or bounced against the steps c, to be thus turned over,
propelled and spread out again, the latter result being illustrated in figure 3 of the
drawing.
The said steps e may consist of bars to which the bolting silk is fastened, and which
may be open or cut away near their middle as at e* in order to serve as sifting
surfaces at this more or less vertical part of the bolting silk against which the material
strikes.
The length of the several sieve-sections is dependent on the nature of the material
to be sifted, on the specific gravity of the same, and on the length of the stroke of the
crank, and should be fixed in an empirical manner according to the respective purpose
the sieve is intended to serve.
In order to limit the length of movement of the material while being thrown
forward, I may arrange over the several sieve-sections one or more bars e fastened in
the rocking sieve-frame so that the material in its forward movement will strike
against them and thus be controlled in the length or extension of its forward
movement.
Two of said retaining bars arranged over each sieve-section near the front and rear
end of the same, will produce good results, particularly in combination with rotary
sieves, inasmuch as they assist the action of the stopping steps c in retaining or
controlling the movement of the material while thrown in the backward direction. I
do not however confine myself to he employment of such retaining bars e.
Figure 4 represents a number of my improved sieves arranged side by side and
provided with the said retaining and propelling steps c as described, the said sieves

page_text: communicating with each other at one end, this arrangement being represented merely
to show that with my present improved construction of sieve the material can be
compelled to pass across a great length of the sifting cloth in a manner similar to that
more fully described in my former Letters Patent dated June 5th 1888 No. 8237.
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 :-
First. In apparatus for sifting or screening flour and other materials the arrange-
ment of the sifting surface so as to form a number or series of sieve sections which are
separated from each other, by steps acting to cause a progressive positive movement
turning and spreading of the material to be sifted to take place in the direction from
the inlet to the outlet on imparting a rocking, reciprocating or rotary motion to the
said sifting surface.
Second. In apparatus for sifting or screening flour and other materials the arrange-
ment of one or more retaining bars above the sieve sections, substantially as described
and for the purposes specified.
Dated this 19th day of March 1889.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.