Sieve device for fine cleaning of grainy material

Abstract

A sieve device for fine-cleaning of grainy material after preliminary cleaning in an aspirator, having an inclined body made of separably integrated frames, in which replaceable stationary sieve are placed one below the other, the upper sieve having openings corresponding to the size of the grain, and the lower sieve having openings smaller than the grain, while a charging hopper is mounted in the upper, peripheral part of the body above the upper sieve. The each sieve consists of cascading identical flat sieve segments connected in sequence by z-shaped connectors, so that the planes of all sieve segments are parallel and above each z-shaped connector there is a set of plates mounted pendulously and independently on a bracket mounted on the frame of the body above the sieve, parallel to the z-shaped connector, the combined width of the plates in the set corresponding to the width of the sieve segment.

Claims

1. A sieve device for fine-cleaning of grainy material, having an inclined body made of separably integrated frames, in which replaceable stationary sieves including an upper sieve and a lower sieve stationary within the inclined body are placed one below the other, the upper sieve having openings corresponding to the size of the grain, and the lower sieve having openings smaller than the grain, while a charging hopper is mounted in the upper, peripheral part of the body above the upper sieve, and each sieve consists of cascading identical flat sieve segments connected in sequence by z-shaped connectors, so that the planes of all sieve segments are parallel, characterised in that above each z-shaped connector there is a set of plates mounted pendulously and independently on a bracket mounted on the frame of the body above the sieve, parallel to the z-shaped connector, the combined width of the plates in the set corresponding to the width of the sieve segment; and the ratio of the distance between the planes of adjacent sieve segments to the length (l) of the sieve segment fulfils the condition $0.03\le \frac{d}{l}\le 0.25,$ and the ratio of the length (l) of the sieve segment to the width (k) of the sieve segment fulfils the condition $0.25\le \frac{l}{k}\le 0.5.$

2. The device according to claim 1, characterised in that the body along with the sieves is inclined relative to the ground at an angle (α) fulfilling the condition 5°≤α≤55°.

3. The device according to claim 2, characterised in that the body further comprises bands with an adjustable length configured to support the body.

4. The device according to claim 3, characterised in that the charging hopper is configured to be placed below an outlet of an aspirator.

5. The device according to claim 2, characterised in that it has a beater mechanism cyclically striking against the body.

6. The device according to claim 2, characterised in that the location of the brackets along with a set of plates relative to sieve segments and relative to z-shaped connectors is adjustable.

7. The device according to claim 6, characterised in that when fine-cleaning light grainy material of a small size, the plates at rest are positioned near the edge of the higher situated sieve segment, and the lower edge of the plates is away from the surface of the lower situated sieve segment by a distance of slightly less than the grain size.

8. The device according to claim 6, characterised in that when fine-cleaning heavy grainy material of a large size, the lower edge of the plates at rest leans against the surface of the lower situated sieve segment.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 presents schematically a complete body suspended under the outlet of an aspirator.

(2) FIG. 2 presents a simplified view without a charging hopper.

(3) FIG. 3 presents a cross-sectional view along the line of FIG. 2.

DETAILED DESCRIPTION

(4) The device according to the invention is illustrated in an embodiment in the drawing.

(5) The body 1 consists of two identical frames 2 separably connected to each other. The upper sieve 3 having openings corresponding to the grain size is placed in the upper frame 2, and the lower sieve 3′ having openings smaller than the grain is placed in the lower frame 2. The charging hopper 4 is mounted in the higher part of the body 1, above the upper sieve 3. The upper sieve 3 consists of cascading identical flat sieve segments 5 with openings corresponding to the grain size, and the lower sieve 3′ consists of identical flat sieve segments 5′ with smaller openings. The adjacent segments 5 and the adjacent segments 5′ are connected to each other by a z-shaped connector 6, so that the planes of all sieve segments 5, 5′ are parallel. Above each z-shaped connector 6 there is a set of plates 7 mounted pendulously and independently on a bracket 8 mounted on the frame 2 of the body 1 above the sieve 3 and 3′, parallel to the z-shaped connector (6), the combined width of the set of plates 7 corresponding to the width of the sieve segment 5, 5′. Each plate 7 in the set is suspended on the bracket 8 by means of two circular hangers 9. The brackets 8 are mounted on the frames 2 by means of bolts 10, which enable both raising and moving the brackets 8 relative to the frame 2. The body 1 along with the sieves 3, 3′ is suspended on the supporting construction 11 of the aspirator 12 by means of bands 13 with an adjustable length, so that it is inclined relative to the ground at an angle α ranging from 5° to 55°, the charging hopper 4 being placed under the outlet 14 of the aspirator 12. Next to the hopper 4, in the end of the upper frame 2 there is a flange 15 shielding against accidentally dropped grain. Moreover, the frame 2 in its upper and lower part has hooks 16 used to mount the bands 13. In order to facilitate the removal of grain obstructing the openings in the sieve 3 or contaminants in the sieve 3′, it is possible to use a beater mechanism 17 striking against the body 1 with the sieves 3, 3′. When fine-cleaning light grainy material of a small size, the plates 7 at rest are positioned near the edge of the higher situated sieve segment 5, 5′, and the lower edge of the plates 7 is away from the surface of the lower situated sieve segment 5, 5′ by a distance of less than the grain size, which allows avoiding the blocking of light grain, for example grass grain, on the plates 7 when sliding on the sieve segments 5, 5′. When fine-cleaning heavy grainy material of a large size, the lower edge of the plates (7) at rest leans against the surface of the lower situated sieve segment 5, 5′, which allows cleaning of the sliding grain, for example corn, with higher efficiency. It has been determined empirically that a preferable result of cleaning grainy material can be achieved with a ratio of the distance d between the planes of adjacent sieve segments 5 or 5′ to the length 1 of the sieve segment 5, 5′ of no less than 0.03 and no more than 0.25, and with the ratio of the length 1 of the sieve segment 5, 5′ to its width k of no less than 0.25 and no more than 0.5.

(6) The operation of the device is as follows: grainy material cleaned of light contaminants in the aspirator 12 falls out of the outlet 14 directly into the charging hopper 4 placed on the body 1 suspended on the supporting construction 11, and when sliding on the sieve segments 5 with openings corresponding to the grain size, it passes onto the lower sieve 3′ positioned below, with openings smaller than the grain size. After reaching the edge of the z-shaped connector 6 it encounters an obstruction in the form of a set of plates 7, on which it loses its kinetic energy, so that on the next segment 5 it begins its travel with a zero velocity, wherein the steadily moving grain cleans the obstructed openings. Such a process is repeated on each sieve segment 5, and only large contaminants remain at the end of the sieve 3, falling into a trough placed outside. A similar process is repeated on the lower sieve 3′, except grain and fine heavy contaminants are present on sieve segments 5′, falling through openings smaller than the grain below the sieve 3′, and the grain slides on the subsequent segments 5′ to be ultimately received via a conveyor in a store-house.