Year: 1895

page_text: Date of Application, 4th Apr., 1895-Accepted, 24th May, 1895
A communication from FR. BRANDSTAEDTER, Engineer and Manager of Steam
Mills, Louvain, Kingdom of Belgium.
1, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent, 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 :-
This invention relates to improvements in sieves.
The said improvements
include devices for propelling along the sieve the material to be sifted, and also
devices for keeping the silk or sifting mesh clear of obstructions.
The propelling devices are arranged in channels and are transverse to the length
of the cases containing the sieves; they may be fixed directly to the frame of the
sifter or fixed in a special transport-frame, arranged movably and displaceable in
the frame of the sifter.
These propelling devices hereinafter called "transporters," are placed
rectangularly across the entire width of a canal, arranged in the screen or sifter
and do not touch the silk or sifting surface as will hereinafter be explained by the
aid of the accompanying drawings; the matter to be sifted is conducted above and
passes beneath the said transporters.
These latter may be of various shapes as, for instance that of wedges with flat
or curved transporting surfaces.
Figure 1 is a plan of a flat sieve or screen oscillating in a circle i.e. so oscillated
that all points of the sieve surface describe or approximately describe circles of
one diameter, and divided into two longitudinal channels in which are arranged the
transporters bb or transverse laths whereof the vertical cross-section is in the
form of a wedge;
Figure 2 shows, in plan, the same arrangement, only with this difference, that in
this case the transporters are short laths or beads ce¹ set on edge, and being wedge-
shaped in horizontal section ;
Figure 3 shows a vertical longitudinal section of the arrangement shown in Fig. 1.
It will be noticed that the transporting face of the transporters is flat;
Figure 4 is a modification of Fig. 3 with rounded faces to the transporters ;
Figure 5 represents a vertical longitudinal section of the arrangement shown in
Figure 2 the transporting faces being flat;
Figure 6 is a plan of a modification of Figure 2 with round transporting faces;
In all the foregoing figures the transporters are supposed to be fixed to the
frame of the sieve; but, as has before been stated, they may also be fixed in a
special frame as shown in the section Figure 7 as a constructive modification.
Figure 8 explains diagrammatically the advance of the matter to be sifted,
conducted above also and passing beneath the transporters;
When the sieve oscillates in a circle, it is the face or head of the wedge which
thrusts the matter to be silted before it, while the point or edge cuts and separates
it so as to prevent it from settling and clogging.
The transport-frames can be arranged in the sitting cases in such manner that
an intermediate space is.. left free; at each. end or side; .for motion; in the former
case a reciprocating longitudinal motion of the frame takes place; in the latter
instance that motion becomes lateral ;

page_text: Figures 9 to 12 show diagrammatically the four principal positions of the
crank-arm or eccentric actuating the sieve and the arrows indicate the direction in
which the transporters move the matter to be sifted.
The succeeding figures of the drawings will be hereinafter again referred to.
The device for keeping the silk or mesh clear is in the lower receptacle for the
sifted material and consists of transporting frames, constructed of transporting
elements d like those described above and illustrated in Figures 1 to 8 of the
accompanying drawings.
These devices are movable and similarly displaced either longitudinally or
laterally; and scrapers are provided above them, as shown in Figures 13 and 14,
and may be of various forms and dimensions but preferably stretched transversely
in the form of strips of india-rubber or ribbons a and placed preferably equidistantly
apart in such manner that when for example the longitudinal displacement of the
frame R is 2 centimetres the interval between the scrapers does not exceed
2 centimetres. In place of strips or ribbons one may use metallic wires, brushes etc.
or select any other convenient and appropriate material whatever.
The approximation of the scrapers to the under side of the gauze of the
sieve .e., the sifting surface, in such manner that they may exercise a gentle
upward pressure thereupon, may be effected by means of resilient springs carrying
a guide-bar whereon the scraper-frame slides to and fro. But that resilience may
be obtained by the flexion of the gauze itself, in which case the weight of the
material to be sifted would impart sufficient resilience to the action, so that
practically the springs can be dispensed with.
Having now particularly described and ascertained the nature of this said inven-
tion as communicated to me by my foreign correspondent and in what manner the
same is to be performed I declare that what I claim is :-
--
1. In bolting or sifting machines for coarse or fine products with sieves oscillating
in a circle, transporting the material to be sifted by means of transporting elements
in the form of wedges arranged in channels the whole width of which they traverse
without however touching the sifting surface the said transporters being provided
with either flat or round transporting surfaces which push the material to be sifted
and thus effect its transport and having a point or edge which separates it, and
being secured to the sieve-frame or arranged in a separate movable frame
reciprocating inside the sieve-frame and set in motion by the reciprocation of the
sieve substantially as described.
2. In combination with the transport-devices described in Claim 1, the cleansing
of the gauze of the sieve and simultaneous transport of the sifted material falling
from the sifting surface of the sieve effected by means of scrapers of various forms
and dimensions equidistantly arranged from one another transversely to the direction
of their motion pressing resiliently against the underneath surface of the gauze of
the sieve and so displaced to and fro by the reciprocation of the frame that they
scrape the whole of the sifting surface of the gauze of the sieve while the sifted
material falls between them where the wedge-shaped transporting devices arranged
below the scrapers conduct the sifted material to either extremity at will,
substantially as described.
3. The improvements in or relating to sieves substantially as and for the purpose
herein before described with reference to the accompanying drawings.
Dated this 4th day of Anril 1805
BOULT & WADE,
Agents for the Applicant.