Improvements in Flour Sifting Sieves.
Year: 1893

page_text: Date of Application, 29th Aug., 1893
Complete Specification Left, 10th May, 1894-Accepted, 16th June, 1894
PROVISIONAL SPECIFICATION.
Improvements in Flour Sifting Sieves.
I, FRIEDRICH SCHLEE, of Haugenow, Mecklenburg, Germany, Engineer do
hereby declare the nature of this invention to be as follows:-
My invention relates to those kinds of sieves and sieving machines (such as
round and surface sieves) which are used for sifting meal or other finely powdered
substances, and the chief objection to which has always been that their flat or
cylindrical surfaces, as the case may be, and to form which silk-gauze or other
similar material is used, become clogged up through the adhesiveness of the meal
or other powdered material, which has to be sifted, whereby the sieving power and
action of the same is considerably reduced.
To counteract this, these sieves are furnished with extra cleaning arrangements,
such as strikers or brushes and in some cases the object required is attained
through the employment of sand or similar material which is from time to time
put into and shaken up in the sieve, whereby the meal or other dust is disengaged
from the gauze so that when the sand is taken out again it comes away with it.
All these methods of cleaning however injure the sieving surfaces; the strikers
shake the silk gauze so violently that the same becomes quickly loose and useless,
while the rubbing of the sand and the continual contact of the brushes wear out
the gauze in a very short time.
The present invention renders all these arrangements for cleaning the sieve
surface superfluous, the necessary result being brought about solely through the
manner in which the sieve surfaces are arranged.
In all sieves, whether the movement be circular, shaking or swinging in which a
woven material (preferably silk-gauze) is used, the sieving cloth, according to this
invention is not stretched flatly or cylindrically, but undulatingly over the frame,
so that folds in the form of waves are produced in the sieving surface.
The material to be sifted passes straight, aslant or in equal directions over the
undulations of the sieve cloth so that the latter is in constant movement with the
result that the adhering meal or other dust is loosened, or is altogether prevented
from sticking to the sieve surface.
The material which is being sifted keeps the undulations in constant movement,
for as it passes over the waves or against them, the outward curves or tops of
the undulations are changed every instant into troughs or inward curves and then
again instantly return to their former position. Through this continual motion the
dust has not time to stick but falls back with every movement of the undulations
and the minute holes of the sieve are thereby kept continually open.
It is also found that when these undulations are employed, a larger surface than
is possible in the level surface sieves may be stretched with sieve cloth and
profitably used.
Dated this 29th day of August 1895.
ust
S. S. BROMHEAD,
97, Newgate Street, Agent for Applicant.

page_text: Improvements in Flour Sifting Sieves.
I, FRIEDRICH SCHLEE of Halle-on-Saale, Mecklenburg, Germany, 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 those kinds of sieves and sieving machines (round and
surface sieves and the like) which are used for sifting meal or other finely powdered
substances, and the chief objection to which has always been that their flat or
cylindrical surfaces to form which silk, gauze or other similar material is used,
become clogged up through the adhesiveness of the meal or powdered substances
which have to be sifted, whereby the sieving power and action of the same is
considerably reduced.
To counteract these difficulties the sieves are furnished with extra cleaning
arrangements, such as strikers or brushes and in some cases the object required is
attained through the employment of sand or similar material, which is from time
to timè put into and shaken up in the sieve; whereby the meal and other dust is
disengaged from the gauze so that when the sand, is taken out again the meal or
other dust comes away with the sand.
All these methods of cleaning however injure the surfaces of the sieves, the
strikers shake the silk gauze so violently that the gauze becomes quickly loose and
useless, whilst the rubbing of the sand and the continuous friction of the brushes
wears out the gauze in a very short time.
The present invention renders all these arrangements for cleaning the sieve
surfaces superfluous, the result being brought about solely through the manner, in
which the sieve surfaces are arranged.
In all sieves, whether the movement be circular, shaking or swinging in which a
woven material, silk gauze or the like is used, the sieving cloth, according to this
invention is not stretched flatly or cylindrically but undulatingly over the frame, so
that wave-formed folds are produced in the sieving surfaces.
I will now describe the invention with reference to the accompanying drawings
in which
Fig. 1 represents a longitudinal vertical section on the line x-x of Fig. 3 of a
sieve intended for rotary movement and embodying my invention.
Fig. 2 represents a cross section of the same on the line y-y of Figs. 1 and 3.
Fig. 3 represents a plan of the same.
Fig. 4 represents a view similar to Fig. 1, but partly broken away, of a form of
sieve adapted to horizontal longitudinal reciprocating movement.
Fig. 5 represents a cross section of the same on the line -z of Fig. 4.
Fig. 6 represents a plan view of the same, broken away in the middle like Fig. 4.
These views show two different arrangements of undulations each.
Figs. 7 and 8 show end elevations of different forms of bolting cylinders or
cylindrical sieves, the one having a circular end frame, the other a polygonal one;
and Fig. 9 represents a similar view of a segmental sieve adapted to act by
oscillation.
a, is
The direction which the material will take while being sifted is indicated by
feathered arrows, the unfeathered ones indicating the motion of the sieve.
A, designates the sieve frame on which the bolting cloth or sieve fabric
stretched and nailed or otherwise fastened. This fabric a, is formed with
undulations consisting of outward waves a' and inward waves or wave troughs a².
These undulations are arranged either parallel to the movement of the material to
be sitted or so as to cross the same at a right angle Figs. 7, 8, 9, and left side of

page_text: Figs. 4 and 6, or at any angle of inclination as in the right hand side of
Figs. 4 and 6.
In sieves having a horizontal circular motion whereby the material to be sifted
will be thrown centrifugally against the walls, these latter may also be fitted with
an undulating sieving surface as shown in Figs. 1, 2 and 3.
Dotted lines in Fig. 3 indicate the axis of rotation.
The material to be sifted passes straight, aslant or in equal directions over the
undulations of the sieve cloth, so that the latter is in constant movement, with the
result that the adhering meal or other dust is loosened or altogether prevented from
sticking to the sieve surface, the material, which is being sifted keeps the undulations
in constant movement, for as it passes over the waves or against them the outward
curves or the tops of the undulations are changed instantly into troughs or inward
curves and then again immediately return to their former position.
Through this continuous motion the dust has not time to stick, but falls back
with every movement of the undulations and the minute holes of the sieve are
thereby kept continually open. Another advantage is that where these
undulations are employed a larger sifting surface becomes available than with the
level surface sieves and can therefore more profitably be used.
The undulations in the sieves are obtained by dipping both length edges of the
bolting cloth in water or some other liquid. When drying these edges will contract
and remain contracted, in consequence of which the entire inner surface of the
sieve cloth must form waves or folds, or else I employ a sieve cloth woven in
such a manner that the threads forming the edges of the chain are shorter than the
rest of the chain threads, by which means I reach the same result, to wit; a sieve
cloth with plain flat edges and undulating body.
This bolting cloth should be fastened taut on the frame so that only the
undulations of the sieve move up and down as before mentioned; the waves a¹,
becoming wave troughs a², and vice-versa. This up and down movement of the
waves is easily effected by the least pressure and the movement of the sieve, and is
the peculiarity of this special construction.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is :-
A sieve having an undulating surface formed in such a manner that the sieve
cloth shows undulations only at the free bolting surface, while those parts, fastened
to the frame show no undulations nor folds, substantially as and for the purposes.
set forth.
Джен
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[RICI MIS KUNI UZY D'
S. S. BROMHEAD,
97, Newgate Street, E.C., Agent for Applicant.
S. S. BROMHEAD,
97, Newgate Street, E.C., Agent for Applicant.