NL2009493C2

NL2009493C2 - Roller screen and method for sieving, especially for tubers or such bulbous products.

Info

Publication number: NL2009493C2
Application number: NL2009493A
Authority: NL
Inventors: Dingeman Dijke
Original assignee: Dijke Beheer B V Van
Priority date: 2012-09-20
Filing date: 2012-09-20
Publication date: 2014-03-24

Description

P98614NL00

Title: Roller screen and method for sieving, especially for tubers or such bulbous products.

The invention relates to a roller screen. The invention further relates to a method for sieving, separating or transporting.

Roller screens are known to be used for sieving products, such as but not limited to tubers or such bulbous products, greens, potatoes, 5 vegetables and the like.

EP0704253 discloses a roller screen, comprising a series of rolls having longitudinal axis in a top view substantially parallel to each other, wherein each roll is supported by longitudinally spaced apart first and second supports. Seen in side view the longitudinal axis of the rolls extend 10 at an angle relative to a horizontal plane. The rolls are driven rotating around their longitudinal axis, in order to move bulbs or such products over the surfaces of the rolls, from the higher first end to the lower second end. Contaminants, such as small stones, earth and the like can pass through the spaces between the adjacent rolls. In this roller screen adjacent rolls are 15 driven in opposite directions, alternating such that the products carried by the rolls are following a zig-zag pattern down. The width of the gap between adjacent rolls can be set by moving the rolls apart in the surface of the screen, such that contact intensity between the products and the rolls can be set, depending on for example size of the products moving along the surface. 20 At least one of each set of two adjacent rolls is provided with a scraping surface, for scraping off mud from the products.

In this screen the first supports are provided at the upper first ends of the rolls, on a first frame portion. The second supports are provided at the lower second ends, on a second frame portion. The angle for all rolls 25 can be set by moving the second frame portion relative to the first frame 2 portion. This makes that the screen is not very versatile and allowable adjustments are limited.

The present disclosure aims at providing a roller screen as an alternative to existing roller screens. The present disclosure aims at 5 providing a roller screen being settable to different products and contaminations. The present disclosure aims at providing a roller screen allowing setting of the angles of rolls at set the spaces between adjacent rolls. The present disclosure aims at providing a screen which is easy to use and maintain and is reliable in use. The present disclosure further aims at 10 providing a method for sieving, alternative to known methods for sieving. The disclosure aims at providing a method for sieving in order to sieve contaminations from product, select products, based on for example size, and/or transport and/or clean products at least in part.

In a first aspect a roller screen a roller screen can be 15 characterised by a series of rolls having longitudinal axis in a top view substantially parallel to each other, wherein each roll is supported by longitudinally spaced apart first and second supports. A first series of the first supports can be movable relative to a second series of first supports, such that the rolls supported by the first series can pivot relative to the rolls 20 supported by the second series. In embodiments the rolls supported by the first series can pivot relative to the rolls supported by the second series, especially pivoted around the second supports. By pivoting the first series relative to the second series of rolls, different angles can be obtained for different rolls, setting the sieving or selection spaces between rolls or sets of 25 rolls.

In another aspect the present disclosure can be characterised by a screen for a roller screen, wherein the rolls are supported by first supports at a first end and by second supports at a position between the first ends and longitudinally opposite second ends, such that the second ends extend 30 beyond the second supports as unsupported free ends. There are no supports 3 or bearings or such elements at or near the second ends, such that the second ends or, preferably, the parts between the second supports and the second ends are unsupported and therefore free of any undesired possible obstructions.

5 In another aspect the present disclosure can be characterised by a method for sieving or selecting products, wherein a series of rolls having longitudinal axis extending substantially parallel, seen in top view, is rotated around the longitudinal axes, supported by first and second supports. The first supports of a first series of rolls is moved in a direction 10 including a vertical component, relative to the further first supports, such that the angle of the longitudinal axis of the first series of rolls in a vertical plane is changed relative to the further rolls.

In further elucidation of the present invention embodiments of roller screens, screens for a roller screen and methods will be described 15 hereafter, with reference to the drawings, which show:

Fig. 1 in perspective top view a roller screen;

Fig. 2 in sectional side view along a line II - II in fig. 1 a roller screen of fig. 1, with rolls in a first angular position;

Fig. 3 in sectional side view along a line II - II a roller screen of 20 fig. 1 and 2, with rolls in a second angular position;

Fig. 4 in perspective top view a roller screen of fig. 1, with only a first series of rolls;

Fig. 5 in perspective top view a roller screen of fig. 1, with only a second series of rolls; 25 Fig. 6 schematically the position of two adjacent rolls, relative to each other.

In this disclosure roller screens will be described with reference to screens for bulbous products such as potatoes. However, the screens can be used for any type of product, both natural and artificial. A roller screen 30 according to this disclosure can be used for screening or sieving products, for 4 cleaning or separating out contaminants from a product stream and/or for transporting products. In embodiments roller screens of this disclosure can have rolls for cleaning products or at least removing dirt clinging to the products, such as mud or earth, clay or vegetation.

5 In embodiments of the present disclosure a roller screen can be characterised in that rolls are used for forming the screen, which rolls are supported by supports, such that the rolls each have a free end. In this description free end has to be understood as including at least an end or end portion of a roll which is not supported by the first or second supports, such 10 that the outer surface and the actual end of the rolls are not obstructed by such support in said end portion. Preferably the rolls have a longitudinal axis extending at an angle relative to a horizontal plane, wherein the free end is a lower end of the roll.

In embodiments the rolls of a roller screen can be hollow. The 15 rolls can be pipes or such substantially cylindrical elements. In embodiments the rolls can be supported by spaced apart first and second supports, at least one of which can be supporting the rolls on an outer surface of the rolls. In embodiments the rolls can be supported in a position longitudinally spaced apart from opposite first and second ends, wherein the 20 relevant supports can comprise support rolls or wheels or the like rotating or low friction elements onto which the rolls can be laid up.

In embodiments the rolls of a screen can be supported by spaced apart first and second supports, which are movable relative to each other. In embodiments the rolls can be supported by first supports at or near an end 25 of the rolls, and by the second supports longitudinally spaced apart from the first end and from the opposite second ends. In such embodiments the first supports can be divided into at least two series, wherein the first series is movable in a substantially up and down direction relative to the at least one other series of first supports. Thus the angular direction of the rolls of the 30 first series can be changed relative to the angular direction of the rolls of the 5 at least one other second series. In embodiments the first supports can alternatingly belong to a first series and a second series, wherein preferably at least one of the series is movable in its entirety.

In embodiments the rolls can be supported by second supports 5 spaced apart from both opposite ends of the rolls, such that at least one series of the rolls can be pivoted around the second supports. In embodiments the rolls can be driven near second supports, positioned spaced apart from opposite first and second ends of the rolls, wherein the rolls can pivot at or near the second supports. The driving can be obtained 10 through snares, belts, chains or such drive elements, or by friction drives, for example by driven wheels or rolls, such that the drive means can be maintained in the same position, irrespective of the angular positions of the rolls. When using belts, chains or the like, the rolls can be pressed onto and/or into the second supports by said drive means.

15 Fig. 1 shows in top view an embodiment of a roller screen 1 according to this disclosure. This screen comprises a row of roll 2, each having a longitudinal axis X. The rolls are supported by first supports 3 and second supports 4. The second supports 4 are longitudinally spaced apart from the first supports 3. In the embodiment shown the second supports 4 20 are positioned between first ends 5 of the rolls 2 and longitudinally opposed second ends 6. The first end 5 of each roll 2 is carried by a first support 3. The opposite second end 6 is free from any support. The portions 7 of the rolls extending from the second supports 4 in a longitudinal direction away from the first supports 3 are in this embodiment unsupported by external 25 supports and are therefore free end portions 7. In embodiments the portions of the rolls extending between the first and second supports 3, 4, preferably including the second supports 4 and more preferably also the first supports 3 can be covered by a guard or cover 8, such as a lid, flap, cover or the like, which can be made of any suitable material, such as but not limited to 6 metal, plastic, fabric, foil or any other suitable material. This prevents the supports 3 and/or 4 from being contaminated.

The first supports 3 can comprise bearings 11 holding the rolls allowing rotation thereof around their longitudinal axis X. By providing the 5 second ends 6 as free ends, and providing for the free end portions 7 of the rolls, the advantage can be obtained that products and contaminations are kept easily away from any bearings. Moreover, products and contaminations will not be obstructed on the rolls or in the gaps. The longitudinal length L of the rolls 2, and especially the longitudinal length Li of the free portions 7 10 thereof can be chosen freely, depending on for example space available, products to be moved over the surface of the screen 1 and the like considerations.

The outer surfaces 9 of the rolls 2 can be made of any suitable material and can be cylindrical, having a constant cross section along the 15 longitudinal length, at least in the free end portion 7. In other embodiments the surfaces 9 can be profiled, for example threaded, grooved, wavy or any other suitable profile, for example for increasing or decreasing contact between rolls 2 and products carried thereon, or roughened, provided with profiling such as knobs, protrusions, rills or any such outward or inward 20 protruding elements.

The outer surfaces 9 of the rolls 2 may be spaced apart over a distance d maximum, seen in the top view. The distance d may lead to gap 10 between adjacent rolls 2, which may in top view have a constant width d.

In embodiments a first series 12 of the first supports 3A (fig. 5) is 25 movable relative to a second series 13 of first supports 3B (fig. 4). The rolls 2 supported by the first series 12 can pivot relative to the rolls 2 supported by the second series 13. In embodiments at least the rolls 2 supported by one of the first and second series 12, 13 can be pivoted, especially around, that is for example at, about or in the second supports 4. In embodiments both 30 series 12, 13 can be movable.

7

In the embodiment shown the first supports 3 of the first series 12 are mounted on a first mount 14 and the first supports 3 of the second series 13 are mounted on a second mount 15. The first mount 14 is movable relative to the second mount 15. The first mount 14 can be movable relative 5 to the second mount 15 in a substantially vertical direction U or a direction substantially perpendicular to the longitudinal axes X, or, as shown, pivotably around an axis Z extending substantially horizontally below the second supports. The second supports 4 preferably support the rolls 2 from below, wherein they are preferably placed onto the second supports and held 10 on the second supports by drive belts, chains or the like, designed for driving the rolls 2 around the longitudinal axis X. In embodiments a first series of the second supports can be mounted on the movable second mount 15 and a seconds series of the second supports 4 can be mounted on the first mount 14, preferably alternatingly.

15 In another embodiment the second supports 4 can also hold the rolls 2 and can be divided into a first series and a second series of second supports, movable in a direction enclosing a vertical component and, preferably, substantially vertically and/or perpendicular to the longitudinal axis X, such that the rolls 2 supported by the first series 12 of first supports 20 3A and the first series of second supports 4 can be moved relative to the other rolls 2, without pivoting, or with a different pivoting of the rolls relative to each other rolls 2.

The second supports 4 can comprise a series of rotatable support elements 16, such as wheels, wherein the rolls 2 are supported on peripheral 25 surfaces 17 of the rotatable support elements 16. In embodiments the rolls 2 are driven by a belt or snare drive 18. The belt or snare 19 of the belt or snare drive 18 are led over the rolls 2, especially over the outer surfaces 9, preferably such that the rolls 2 are pulled onto the second supports 4 by the or each snare or belt 19.

8

In side view the longitudinal axes X of the rolls 2 can extend at an angle a relative to a horizontal plane H, indicated by the horizontal line H in fig. 2. Preferably the longitudinal axes X of the first series of rolls 12A extend at an angle ai different from the angle aa that the longitudinal axes 5 X of the second series 13A of rolls 2 enclose with the horizontal plane. The rolls of the first series 12A and the rolls of the second series 13A can be positioned alternating, such that, possibly except for the most outer rolls 2, a roll 2B of the second series 13A is placed between two adjacent rolls 2A of the first series 12A and vice versa.

10 In the embodiment as shown, where the rolls can pivot relative to each other, especially around a point or line at or near the second supports 4, the gap 10, which in top view is substantially rectangular, can be widening towards the free second ends 6, seen in side view. It can have a substantially triangular shape, seen in a plane W defined by the 15 longitudinal axes X of the relevant rolls 2. In embodiments the rolls 2 of the first and second series 12A, 13A can be pivoted for example between a position in which the longitudinal axes X are substantially parallel in side view and a position in which they include an angle 6 which is defined by the I ai - CL2 I which can for example be between 1 and 10 degrees. In 20 embodiments the angle 6 can for example be such that in side view the second end 6 of roll 2B in the second series can extend above the second end 6 of a roll 2A in the first series 12A or vice versa. Thus the size and shape of the gaps 10 can be altered, depending on for example products to be transported and/or sieved, selected or otherwise moved over the screen, 25 and/or contaminations that have to be removed from the products. By having a widening gap 10 different sizes of products and/or contaminants can pass through the gap in different longitudinal positions, such that they can be retrieved by retrieving devices 20, for example transport belts or crates, containers or the like, positioned in different longitudinal positions 30 relative to the longitudinal axes X of the rolls 2, below the screen 1. The 9 products leaving the screen 1 at the lower second end 6A can be retrieved by further retrieving device or devices 21, such as for example a belt, crate, cart, box, container or any other suitable means.

In an embodiment where the rolls 2A and 2B can be moved 5 without tilting the gap 10 can be widened or reduced in width over the full length.

As can be seen in the drawings the rolls can be driven for example by belts, snares or chains 19. In embodiments the rolls 2 can all be rotated around their longitudinal axes X in the same direction, continuously or 10 alternating in opposite directions. In embodiments the rolls can be rotated around their longitudinal axes, in different directions, for example the rolls 2A in the first series 12A in a direction opposite the rolls 2B in the second series 13A, again continuously in the same direction or alternating in opposite directions.

15 In embodiments the rolls can be massive elements, for example made of metal or plastic. In embodiments the rolls can be tubular elements such as pipes, again for example made of plastic or metal. The rolls can be coated with a coating, such as for example a low friction coating, for example smooth plastic, such as Teflon, or a relatively high friction coating, such as 20 rough surface coating, made with rubber or elastomer, which may be relatively hard or relatively soft, depending on for example products to be transported over the screen 1.

A screen for a roller screen 1, can be supported by a frame 23, in a known manner, and can be stationary or can be movable, for example 25 supported by wheels (not shown). In embodiments the screen can be tilted relative to the frame 23, in order to adjust the angle or angles a, to which end a tilting mechanism 25 can be provided, for example a crank mechanism, for tilting the screen around the axis Z.

With a screen 1 according to the present disclosure products can 30 be sieved, selected and/or transported. Products can placed on the screen 1, 10 near the second supports 4, closed to a lower end 24 of the lid 8, and can pass over the screen 1, especially the rolls 2 towards and passed the second, lower end 6A, formed by the free ends 6 of the rolls, or passed through the gaps 10 between the rolls 2, depending on the sizes of the products and/or 5 contaminants and, if applicable, the softness and thus pliability of the surface of the rolls 2 and the rotational movement thereof around their axes X.

For the purpose of cleaning the rolls 2 during, prior or after use, a scraper can arranged along an underside of each roll 2 in the longitudinal 10 direction X thereof, which scraper extends at least throughout the length of the roll 2 between the second supports and the free ends 6, for example approximately centrally under the centerline X of the roller 2 in question. The distance between the scraper and the outer surface of the roll may be adjustable. It is noted that the rollers 2 may instead or additionally be 15 rinsed or sprayed clean with water or the like.

The invention is not in any way limited to the embodiments shown in the drawing and described in the description by way of example only. Many variations are possible. For instance, the rollers may be provided with a brush-shaped surface and the bristles may to some degree extend in 20 the direction of the lower end of the conveying surface for the purpose of a better advancement of the products. The rolls can be composed of all kinds of suitable materials. The number of rolls in the conveying surface, the length thereof and the diameter can be chosen as desired and even during use be adjusted depending on the circumstances.

25 The drive means can be designed in different ways, obvious to those skilled in the art. For instance, use can be made of gear, rope and/or belt transmission, link systems and different kinds of drives. For instance, each roll may be equipped with a gear wheel adjacent the upper end, with the gear wheels of the rolls meshing in pairs. Further, various adjusting and 30 control functions can be controlled both electronically and mechanically.

11

These and many other modifications are understood to fall within the scope of the invention.

Claims

A roller screen, comprising a group of rollers with longitudinal axes which are substantially parallel to each other in a plan view, wherein each roller is supported by longitudinally spaced apart first and second supports, wherein a first group of the first supports is movable with respect to a second group of the first supports, such that the rollers supported by the first group can pivot relative to the rollers supported by the second group, in particular pivot around the second supports.

2. Roller screen according to claim 1, wherein the first supports are placed at first ends of the rollers.

A roller screen according to claim 2, wherein the second supports are placed at a location between the first ends and opposite second ends of the rollers.

4. Roller screen according to any of the preceding claims, wherein the first supports comprise the roller-retaining bearings that allow rotation of the rollers about their longitudinal axis.

5. Roller screen as claimed in any of the foregoing claims, wherein the first supports of the first group are mounted on a first frame and the first supports of the second group are mounted on a second frame, the first frame being movable relative to the second undercarriage, preferably in a substantially vertical direction or a direction that is substantially transverse to the longitudinal axes.

6. Roller screen according to one of the preceding claims, wherein the second supports comprise a group of rotatable support elements, such as wheels.

A roller screen according to claim 6, wherein the rollers are supported on circumferential surfaces of the rotatable support elements.

A roller screen according to any one of the preceding claims, wherein the rollers are driven by a belt or belt drive.

A roller screen according to claim 8, wherein belt or strings of the belt or belt drive are guided over the rollers, preferably such that the rollers are pulled on the second supports by the strings or belts.

10. Roller screen according to one of the preceding claims, wherein the rollers are rotated around their longitudinal axes alternately in opposite directions.

11. Roller screen as claimed in any of the foregoing claims, wherein viewed in side view the longitudinal axes of the rollers extend at an angle with respect to a horizontal plane, wherein preferably the longitudinal axes of a first group of rollers extend at an angle that differs from the longitudinal axes of the further rollers, more preferably alternately.

A roller screen according to any one of the preceding claims, wherein the rollers have second ends that are unsupported, the rollers being preferably pipes.

A roller screen according to any one of the preceding claims, wherein the wherein a security means extends over the first and second supports, preferably over the first and second supports and parts of the rollers between the first and second supports.

14. A roller screen according to any one of the preceding claims, wherein at least one group of the rollers is pivotable with respect to the further rollers, such that substantially triangular gaps can be formed between adjacent rollers, which gaps towards unsupported free ends of the rollers broaden.

A screen for a roller screen, in particular for a roller screen according to any one of the preceding claims, wherein the rollers are supported by first supports at a first end and by second supports at a location between the first ends and second ends opposite longitudinally 5 such that the second ends extend beyond the second supports as unsupported free ends.

16. Method for sieving or selecting products, wherein a group of rollers with longitudinal axes extending, viewed in plan view, substantially parallel, is rotated about the longitudinal axes, thereby supported by first and second supports, the first supports of a first group of rollers with respect to further first supports is moved in a direction with a vertical component such that the angle of the longitudinal axes of the first group of rollers is changed in a vertical plane with respect to the further rollers.