Year: 1888

page_text: Date of Application, 4th May, 1888
Complete Specification Left, 5th Jan., 1889
Complete Specification Accepted, 16th Feb., 188
I, GUSTAV DAVERIO, of Zurich, Switzerland, Engineer, do hereby declare the
nature of this invention to be as follows:-
The improved sifting-machine forming the subject of this invention consists in a
box having two compartments, a stationary upright or inclined sieve forming the
division between the said compartments, a rotative system of beaters which throw the
material to be sifted against the sieve, and means by which blasts of wind alternating
in direction are forced in rapid succession through the same.
For obtaining these means, certain parts of the machine adapted to operate on the
air contained therein, are made movable and put in oscillating motion, so that the air
will be alternately compressed and rarified in either compartment, the compression.in
the one coinciding with a rarefaction in the other. The said movable parts may
consist in two loose walls, one of either compartment, connected at their rims to the
box of the machine by strips of leather or cloth, and vibrated by eccentrics. Or, one
of the walls only is actuated positively, while the other one consists in a sheet of
cloth, or the like, being sufficiently slack as to be capable of yielding to the variations
of pressure.

page_text: I, GUSTAV DAVERIO, of Zurich, Switzerland, 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:-
The improved sifting-machine forming the subject of this invention consists in a
box having two compartments, a stationary upright or inclined sieve forming the
division between the said compartments, a rotative system of beaters which throw
the material to be sifted against the, sieve, and means by which blasts of wind
alternating in direction are forced in rapid succession through the same.
A sifting-machine carried out according to my invention is shown in the annexed
drawing, Fig. 1 being a transverse and Fig. 2 a longitudinal section. Fig. 3 repre-
sents a modification of the machine.
The sieve D, fixed to a stationary frame, forms the division between the two
compartments C and N. In the compartment C is arranged the system of beaters B,
fixed to a shaft, which is put in rotation so that the material to be sifted, introduced
at A, is thrown by the beaters against the sieve. The bottom of the compartment C
is formed in an arc of a circle adapted to the course of the beaters and joining the
sieve, so that the material which has not passed through the meshes of the latter,
drops back into the reach of the beaters so as to be thrown anew against the sieve.
At the same time the beaters, which are arranged askew to their axis of rotation, push
the material in the compartment C forward, the coarse residue finally issuing through
the aperture E.
For the purpose of forcing blasts of wind in alternate directions through the sieve,
certain parts of the walls of the machine adapted to operate on the air contained in
the latter, are made movable and put in oscillating motion, so that the air will be
alternately compressed and rarified in either compartment, the compression in the one
coinciding with a rarefaction in the other. According to figures 1 and 2 the said
parts consist in the upper wall F of the compartment C, and the lateral wall G of the
compartment M. These walls are connected at their edges to the box of the machine
by strips of leather or cloth, and they are actuated so as to move to and fro vertically
to their own planes by two pairs of eccentrics H and I, keyed to a shaft which is
driven by the beater-shaft, the parts being so arranged that, when the wall F moves
inward, the wall G moves outward and vice-versa. Each motion of the combined
walls thus produces in one compartment a compression, in the other a rarefaction of
air, in consequence whereof the air being close to the sieve is continually forced
through the same in alternating direction. When the air traverses the sieve in the
direction towards the compartment N, it operates to promote the passage of the fine
particles of the material through the meshes thereof, whereas by its backward motion
it clears the meshes of the particles having penetrated thereinto without passing
through and which stop them up.

page_text: In the modified arrangement of the machine represented by Fig. 3, the alternate
blasts of wind are produced by the moveable wall F alone, which is actuated by the
two eccentrics H; whereas the movable portions of the wall of the compartment N
consists in sheets of cloth G³, adapted to prevent the fine material from passing
through in the form of dust, the said sheets being fixed to frames M with sufficient
slack as to be capable of yielding to the varying pressures produced by the wall F,
and the walls KL of the box of the machine are provided with slits for allowing air
to enter from outward into the spaces between these walls and the sheets G³, and to
issue therefrom, in order that the sheets may oscillate freely.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
A sifting-machine composed of two compartments C and N, a sieve D separating
the said compartments from each other, a system of beaters B adapted to throw the
material to be sifted against the sieve and means for forcing blasts of wind in
alternate directions through the sieve, such as the two movable walls F and G or G¹,
belonging to the respective compartments C and N, one of the said walls or both
being put in oscillating motion by mechanical means, substantially as described.
Dated this Soaand daw of Tarnow 1880
CARL PIEPER,
Agent for Applicant.