GB2118071A

GB2118071A - Sifting procedure and apparatus

Info

Publication number: GB2118071A
Application number: GB08309330A
Authority: GB
Inventors: Vilppu Uolevi Rissanen
Original assignee: Oljynpuristamo OY
Current assignee: Oljynpuristamo OY
Priority date: 1982-04-07
Filing date: 1983-04-06
Publication date: 1983-10-26
Also published as: SE8301865D0; IT8348066A0; GB2118071B; DK152283A; DK152283D0; FI821229A0; FI71239B; ZA832427B; FR2524825B1; SE8301865L; DE3312365A1; DK157979C; DK157979B; CA1211079A; IT1164648B; FI71239C; SE455051B; FI821229L; FR2524825A1

Abstract

In a sifting procedure for treating materials difficult to sift, in which any one component of the material tends to become adherent to the surface of the sieve, e.g. a mixture consisting of sunflower seeds and of other kinds of inflorescence material accompanying them, the adhesion problem has been solved by using a brush roll (3) disposed against the surface of the sieve e.g. a rotatable drum sieve (2), in the manner that the brush roll is rotated about its own axis (4) and, at the same time, the surface of the sieve and the brush roll are displaced in relation to each other. Hereby the brush roll (3) sets the material to be sifted in motion and, on the side, detaches material that has become adherent to the surface so that the sieve is kept permeable. To the purpose of moving the material to be sifted, introduced at one end of the drum sieve (2), during the sifting process towards the opposite end of the sieve, the brush roll (3) may be provided with a helical thread moving the material to be sifted. <IMAGE>

Description

SPECIFICATION Sifting procedure and apparatus The present invention concerns a sifting procedure intended for the treatment of materials difficult to sift, where one of the components in the material tends to become adherent to the surface of the sieve.

In sifting methods of prior art, sifting is accomplished by vibrating the sieve, whereby the material on the surface of the sieve is set in motion, or when a drum sieve is used by rotating the sieve about its own axis. It is then a precondition for successful sifting that the components of the material that is being sifted do not adhere to the surface of the sieve nor to each other. If such tendency of adhesion is present, sifting in conventional manner merely by the aid of vibration or rotation of a drum sieve is not feasible.

This adhesion problem has been met in the harvesting of sunflower seeds by the procedure disclosed in the Finnish patent application No.

81 2221. In the said procedure the flower heads are severed with a cutter so that the seeds are cut off from the floral axis therebelow. The separation is however not complete in practice: with the seeds is entrained floral axis residue and other kinds of inflorescence material and this has to be separated from the seeds by sifting. Since it is possible according to this procedure to harvest the floral heads in moist condition, the moisture in the floral axis residue and other inflorescence material causes the adhesion problem mentioned.

Therefore the sifting is not feasible by conventional sifting methods based on vibrating or rotating the sieve.

The object of the present invention is to provide a sifting procedure wherein adhesion of the material being sifted, and consequent blocking of the sieve, is no longer incurred. The procedure of the invention is characterized in that in the sifting process is used a brush roll disposed against the surface of the sieve, in such manner that the brush roll is rotated about its own axis and, at the same time, the sieve surface and the brush roll are displaced with reference to each other, whereby the brush roll sets the material in the sifting process in motion and on the side thereof detaches material that has become adherent to the surface of the sieve, so that the sieve is kept permeable.

The primary function of the brush roll movable with reference to the sieve surface, in the procedure of the invention, is to keep the sieve surface clean so that the sifting of materials difficult to sift is possible in the first place. In addition, the brush roll serves as a member setting the material into motion bringing about its sifting, whereby for instance vibration of the sieve is superfluous.

It is to advantage to apply the invention in sifting carried out with a rotating drum sieve. This may be carried out by positioning the brush roll against the inner surface of the sieve and by rotating it about its own axis in the direction opposite to the direction of rotation of the sieve.

The displacement of the brush roll with reference to the sieve surface is then based on the rotary movement of the sieve because, apart from its own rotary motion, the roll may be stationary.

When using a drum sieve, the feed of the material to be sifted onto the sieve surface is usually through one end of the sieve. It is then to advantage if the material to be sifted moves during the sifting process towards the opposite end of the sieve so that the shifting residue departs through the latter. Such movement of the material-can be enabled by providing either the inner surface of the drum sieve or the brush roll with a helical thread moving the material in the direction of the sieve axis. The particular advantage in using such a thread is that it enables the time which the material to be sifted is delayed to be controlled by the aid of the speed of rotation of the sieve or of the brush roll. Furthermore, the sieve and the brush roll may be horizontally disposed, whereby no hydraulics are needed to tilt and to counterbalance them.

A further object of the invention is a sifting apparatus for applying the sifting procedure just described. This apparauts is characterized in that it comprises, in addition to the sieve, a brush roll disposed against the surface of the sieve, this roll being rotatable about its own axis, and that the sieve surface and the brush roll have been arranged to be movable with reference to each other, whereby the material to be sifted can be set in motion with the aid of the brush roll and at the same time the material that has become adherent to the sieve surface is detachable so that the sieve is kept permeable.

The invention is described in the following, in greater detail, with the aid of an example with reference being made to the attached drawing, wherein: Fig. 1 presents a sifting process according to the invention, with the aid of a brush roll and a rotating drum sieve, and Fig. 2 illustrates the sifting process of Fig. 1, shown in section along the line Il-Il in Fig. 1.

In the drawing is depicted an embodiment of the invention in which as sieve is used a horizontal drum sieve 2 rotating about its axis 1. Against the inner surface of the drum sieve 2 has been mounted a brush roll 3, which rotates about its own axis 4 but is otherwise stationary. The material 5 to be sifted, on the inner surface of the sieve 2, is a mix of which one component or another has a tendency to become adherent to the surface of the sieve and to block the slits in the sieve.

The sifting process illustrated by the drawing is based on opposite rotary motions of the drum sieve 2 and the brush roll 3. The primary task of the brush roll 3 is to prevent adhesion of the material 5 that is being sifted and to keep the sieve continuously permeable. At the same time, the brush roll 3 contributes to set the material 5 that is being sifted in motion with reference to the sieve surface such as is required for sifting.

The material to be sifted is supplied onto the surface of the sieve 2 through the end of the sieve as indicated by the arrow 6 in Fig. 1. The bristles of the brush roll 3 have been set in the configuration of a helix 7, which causes axial displacement of the material 5 to be sifted, during the sifting process, towards the opposite end of the sieve. Under the sieve 2 has been provided a channel 8, into which the component 9 passed by the sieve drops, and the sifting residue departs from the sieve surface as indicated by the arrow 10in Fig. 1.

It would be possible, alternatively, to bring about the axis movement of the material 5 to be sifted, from one end to the other of the sieve, also by the aid of a helical thread provided on the inner surface of the sieve 2. The advantage gained with a helical thread, for instance compared with tilting the drum sieve, is that the displacement of the material will take place independent of the position of the drum, and therefore this design is applicable for instance in harvesting machines, which have to proceed on an uneven base with variable inclination.

As taught by the invention, the material 5 that is being sifted may be for instance a mixture of sunflower seeds and of other inflorescence material accompanying them, such as is obtained in connection with harvesting sunflower seeds.

The component 9 which is sifted through the sieve 2 mounted on the harvesting machine will then consist of the sunflower seeds, and the other kinds of inflorescence material present in the mixture remains on the surface of the sieve. Containing abundant moisture, this inflorescence material displays a tendency to adhere to the sieve surface, but thanks to the action of the moving brush roll, cleaning the surface of the sieve, no blocking of the sieve can occur.

It is obvious to a person skilled in the art that different embodiments of the invention are not confined to the examples presented and may instead vary within the scope of the claims following below.

Claims

1. A sifting procedure intended for treatment of materials (5) difficult to be sifted and in which one component of the material tends to become adherent to the surface of the sieve (2), characteri!ed in that in the sifting process is used a brush roll (3) disposed against the surface of the sieve (2), in such manner that the brush roll is rotated about its own axis (4) and at the same time the sieve surface and the brush roll are displaced with reference to each other, whereby the brush roll sets the material to be sifted (5) in motion and, on the side hereof, detaches material that has become adherent to the sieve surface so that the sieve is kept permeable.

2. Procedure according to claim 1, characterized in that the sifting takes place with a drum sieve (2) which is rotated while at the same time a brush roll (3) disposed against the inner surface of the sieve rotates about its own axis (4).

3. Procedure according to claim 2, characterized in that the inner surface of the drum sieve (2) or the brush roll (3) has been provided with a helical thread (7) which moves the material being sifted, during the sifting process, towards the other end of the sieve.

4. Procedure according to any one of the preceding claims, characterized in that by the procedure are separated sunflower seeds from other kinds of inflorescence material accompanying them.

5. Sifting apparatus for applying a procedure according to any one of the preceding claims, characterized in that the apparatus comprises, in addition to a sieve (2), a brush roll (3) disposed against the surface of the sieve, this roll being rotatable about its own axis (4), and that the sieve surface and the brush roll have been arranged to be movable with reference to each other, whereby the material (5) to be sifted can with the aid of the brush roll be set in motion and the material that has become adherent to the surface of the sieve is at the same time detachable so that the sieve is kept permeable.

6. Apparatus according to claim 5, characterized in that the apparatus comprises a drum sieve (2), against the inner surface of which a brush roll (3) has been disposed so that the drum sieve and the brush roll are simultaneously rotatable.

7. Apparatus according to claim 6, characterized in that the inner surface of the drum sieve (2) or the brush roll (3) has been provided with a helical thread (7) by which the material to be sifted can be moved during the sifting process towards one end of the sieve.

8. A sifting procedure substantially as hereinbefore described with reference to the accompanying drawing.

9. Sifting apparatus constructed, arranged and adapted for carrying out the sifting procedure of claim 8 substantially as hereinbefore described with reference to the accompanying drawing.