EP1764163A1 - Star screen with cleaning arrangement - Google Patents

Abstract

Star-wheel sieving machine provided with in-use cleaning device (15) has star wheels (18) and cleaning-comb fingers (17) of preferably resilient / elastic material. Cleaning device is a hinged rod construction which may be cylinder actuated (44), can simultaneously clean multiple wheel rows, and is mounted above the sieve to exert both a first, 'probing' action and a second, 'contact' cleaning action. The cleaning device (15) is parked above the star wheels and product flow when not in use. When activated, the cylinder moves the multiple comb assembly downward to insert the comb fingers, or tines, into some of the cavities between the star arms on each wheel. The comb moves to a second position where the fingers cause slight deformation of the elastic star arms, to further dislodge adhering material.

Description

The invention relates to a star screen with cleaning device, wherein along a conveying direction a plurality of transverse to the conveying direction Siebwellen follow each with several screen stars on each other, wherein the screen stars each have multiple Siebsternarme, each one space is provided between the on the same screen shaft adjacent screen stars, said the cleaning device on a holder has scrapers for entry into at least some of the spaces, and wherein the holder is movable between a home position in which the scrapers do not enter the spaces, and a first cleaning position in which the scrapers enter the spaces between.

Are known such star screens from the DE 1 006 072 1 , The holder with the scrapers is arranged there below the screen and from a starting position into a cleaning position and back again movable. It has been found that the space between two sieve arms of the same sieve star is more or less glued by the bulk material.

Object of the present invention is to provide a star screen with a cleaning device, wherein the cleaning of the spaces between adjacent sieve arms (the same sieve) are freed of dirt.

The cleaning device according to the invention is characterized in that the holder is movable into a second cleaning position in which the scrapers have contact with the screen arms. Due to the contact of the scrapers with the rotating sieve arms, the sieve arms experience a mechanical stress in the form of a shock. The adhering in the interstices of the Siebsternarme bulk material is thereby loosened and falls by the rotational movement of the screen stars out of the spaces.

In an advantageous embodiment of the invention, the scrapers touch in the second cleaning position Siebsternarme the screen stars, which are arranged on screen shafts, which are adjacent to the screen shafts, between the screen stars the scrapers in the first cleaning position. The meshing arrangement of screen shafts with screen stars is usual, in such a way that screen star arms intervene in the spaces between adjacent screen shafts. By moving the holder in an (upright) plane and with a component parallel to the conveying direction, in this configuration, a strip or striking of the strainer arms during the already provided movement of the holder in the first cleaning position or out of the same is possible.

In an advantageous embodiment, the second cleaning position of the first cleaning position is downstream in the conveying direction. For this purpose, the holder with the scrapers is moved obliquely forwards from the first cleaning position, in which the scrapers rest against the screen hubs. This simply aligned movement allows a simple construction of the holder's suspension. In addition, so the rotation of the screen stars supports the return movement of the holder in the starting position. The scrapers can not be clamped by the rotation of the screen stars.

In one embodiment of the invention, the scrapers touch, in particular free ends thereof, in the second cleaning position, the free ends of the sieve arms.
In this position, the free ends of the strainer arms hit during rotation of the scrapers, whereby the material located in the interstices of the strainer arms is released. Preferably, the strainer arms and the scrapers are made of resilient material, whereby yield both means and the rotation is not permanently hindered when striking the screen arm to the scraper.

The screen stars advantageously define in each case a radial plane, in each of which a scraper engages in the second cleaning position. The movement of the Scraper is located approximately in the same plane as the spanned by the respective sieve radial plane.

In a preferred embodiment of the invention, the holder is arranged with the scrapers above the screen shafts and movable downwards into the first cleaning position. Adding the gaps with bulk material within the cleaning device is thus avoided.

According to an advantageous further development, the holder with the scrapers during the process from the initial position into the first cleaning position describes an arcuate trajectory. On the trajectory the scrapers pass the second cleaning position.

In an advantageous development of the invention, the holder is preferably suspended above the screen shafts on a linkage. The linkage has a parallelogram-like shape, but also any other shape can be selected. The holder is pivotable on the linkage along an arcuate, in particular quarter-circle-shaped movement path. Above all, a quarter-circle movement path allows the scrapers to be fed precisely to the radial plane of the screen stars (in the second cleaning position) and to touch the screen arms.

In a preferred embodiment of the invention, the scrapers are arranged on cross members. The cross member in this case run parallel to the screen shafts, preferably each screen shaft is associated with a cross member with scrapers. In this case, a plurality of cross member, preferably all cross member, part of the frame-like holder. Therefore, only a single drive acting on the holder is sufficient for the movement of the scrapers.

According to a particularly advantageous embodiment of the cleaning device, the movement of the holder takes place hydraulically. Preferably, the holder moves from the starting position in the cleaning positions by its own weight. The return movement of the holder, so from the first cleaning position in the second cleaning position and in the starting position, preferably takes place hydraulically. A single hydraulic drive is sufficient. Alternatively, the cleaning device may also have a plurality of hydraulic drives, in which case each individual drive may be made smaller.

The star screen has a conveying direction predetermined by the rotational movement of the screen shafts so that the area of the screen arm arms facing the conveying side moves in the conveying direction. Advantageously, the movement of the scrapers from the starting position into the cleaning positions takes place against the rotational movement of the sieve arms. It follows that the second cleaning position of each scraper is above and in the conveying direction behind the first cleaning position.

Advantageously, the movement of the holder, preferably the lowering movement, limited by a particular adjustable stop. Depending on the arrangement of the cleaning device to the star screen an exact first and second cleaning position can be selected hereby. The stop also prevents the frame from being pivoted beyond the first cleaning position during the movement from a starting position into the cleaning positions.

In a particularly preferred embodiment of the cleaning device, the movement of the holder takes place obliquely downward in the direction of the screen waves such that the scrapers are movable with their free ends approximately tangential to screen hubs and in particular up to this zoom. The resulting first cleaning position causes a particularly advantageous and sustainable cleaning effect.

Fig. 1

perspektivische Ansicht eines Sternsiebs mit Reinigungsvorrichtung,

Fig. 2

Schnitt durch ein Sternsieb mit Reinigungsvorrichtung in Ausgangsstellung,

Fig. 3

Schnitt durch ein Sternsieb mit Reinigungsvorrichtung in einer zweiten Reinigungsstellung,

Fig. 4

Schnitt durch ein Sternsieb mit Reinigungsvorrichtung in einer ersten Reinigungsstellung,

Fig. 5

eine perspektivische Darstellung der Reinigungsvorrichtung.

Further features of the invention will become apparent from the claims and the description, moreover. Advantageous embodiments of the invention are explained below with reference to drawings. Show it:

Fig. 1

Perspective view of a star screen with cleaning device,

Fig. 2

Section through a star screen with cleaning device in the starting position,

Fig. 3

Section through a star screen with cleaning device in a second cleaning position,

Fig. 4

Section through a star screen with cleaning device in a first cleaning position,

Fig. 5

a perspective view of the cleaning device.

A star screen 10 known from the structure with transverse to a conveying direction 11 and in the conveying direction successive Siebwellen 12, 13, 14 has a cleaning device 15 above a sieve level formed by the sieve shafts. Parts of the cleaning device 15, namely a holder 16 with scrapers 17 are movable from an initial position shown in FIG. 2 along an arcuate, in particular approximately quarter-circular movement path in the direction of the star screen 10 and at the same time against the conveying direction 11. In this case, the scrapers enter intermediate spaces, between each on the same screen shaft 12, 13, 14 arranged screen stars 18, and free the spaces of dirt, space material or the like. The aim is a scraper 17 per space.

The scrapers 17 are held on cross members 19, which are arranged parallel to the screen shafts 12, 13, 14 and in a common plane parallel to the screen plane. In the present embodiment, more screen shafts 12, 13, 14 are provided as cross member 19, for example, twelve cross member 19 in at least sixteen screen shafts.

The cross member 19 are connected at their free ends to each other by longitudinal members 20, 21. For stiffening is still a central longitudinal member 22 is placed centrally on the cross member 19 and connected thereto.

The transverse and longitudinal members 19 to 22 together form the rectangular frame-like holder 16 for the scrapers 17th

The holder 16 is suspended on a parallelogram-like linkage 23, consisting of four pivot levers 24, 25, 26, 27. Regardless of the movement of the pivot lever 24 to 27, the holder 16 is always parallel to the screen plane.

The holder 16 has about each one third of its length, approximately on the (in the conveying direction seen) 4th and 8th cross member 19 each have a reinforcing member 28, 29 parallel thereto. These are each provided with two articulation points 30, 31, 32, 33 for the movable connection with lower ends of the pivot levers 24 to 27. Corresponding to this, the pivot levers 24 to 27 are pivotally held at their upper free ends at articulation points 34, 35, 36, 37 , see in particular Fig. 5.

The upper pivot points 34 to 37 are held on lower sides of transverse bars 38, 39. The latter form with a further transverse bar 40 and two longitudinal bars 41, 42 a rectangular frame-like carrier 43 for the holder 16 hanging thereon.

As a drive for the pivotal movement of the holder 16 relative to the carrier 43, a hydraulic piston-cylinder unit 44 is provided. This is pivoted at one end to a lower cross-beam 45 and at another end to an upper cross-beam 46. The lower cross-beam 45 is aligned parallel to the cross member 39 and connects the pivot lever 24, 25 fixed to each other, about half the length thereof. For connection to the piston-cylinder unit 44, the lower cross-beam 45 approximately centrally a pivot point 47.

The upper cross member 46 is part, namely the base of an inverted U-shaped support bridge 48. Upright legs 49, 50 connect the upper cross member 46 fixedly to the longitudinal members 41, 42 at a short distance to the last in the conveying direction transverse spar 40. For pivotally receiving the piston Cylinder unit 44, the upper cross-beam 46 on the underside a pivot point 51.

To accommodate the longitudinal loads occurring, the support bridge 48 still diagonal struts 52, 53 between the ends of the upper cross member 46 and the longitudinal members 41, 42, that is, in the direction of the cross member 40th

By extending the piston-cylinder unit 44, the holder 16 with the scrapers 17 from a starting position shown in FIG. 2 in a (first) cleaning position shown in FIG. 4 is movable. In this case, the holder 16 and the scrapers 17 pass through another (second) cleaning position according to FIG. 3. In the initial position, the piston-cylinder unit 44 is retracted. The pivoting levers 24 to 27 are directed parallel to the holder 16 and carrier 43 and that starting from the carrier 43 in the conveying direction (arrow 11). Preferably, the unit 44 is driven only to move to the home position. The movement into the first cleaning position can then take place by the weight of the holder 16.

In the first cleaning position shown in FIG. 4, the vertically directed scrapers extend in the gaps up to screen hubs 54 zoom. Specifically, the hub width is about twice as large as the width of the screen arm in the axial direction or something more. Accordingly, the spaces between the sieve arms in the axial direction are as large as or slightly larger than the width of the sieve arm 55 in the axial direction. Accordingly, the scrapers 17 in the axial direction are about as wide as the Siebsternarme, namely suitable for the width of the spaces.

In the first cleaning position shown in FIG. 4, the scrapers 17 extend up to the hubs 54 and precisely above the same. The first cross member 19 in the conveying direction with scrapers 17 is in the first cleaning position shown in FIG. 4 just above the second in the conveying direction Siebwelle 12. Lower free ends of the scrapers 17 zoom up to the screen hubs 54, touch them easily or have only a small Distance to this.

On the arcuate path - in particular along a quarter circle - of the holder 16 from the initial position to the first cleaning position shown in FIG. 4 or on the way back the holder 16 comes with the scrapers 17 in the (second) cleaning position shown in FIG Scrapers 17 free ends of the screen arm 55. Due to the offset or meshing arrangement of the screen stars 18 immediately consecutive screen shafts 12-14 touch the scrapers 17 which occur in the first cleaning position shown in FIG. 4 in the interstices of the screen shaft 12 in the second cleaning position According to FIG. 3, the sieve arms 55 (on the screen stars) of the screen shaft 13 immediately following in the conveying direction. "Touching" here means light contact with the usually elastic or yielding sieve arms 55, in order to slightly deform the screen arms 55 and so on to dissolve adhering dirt, overburden or the like. In particular, this applies to debris in spaces between each of the same sieve star 12-14 sieve arms 55 (gaps in the circumferential direction, as opposed to the spaces in the axial direction in which the scrapers 17 occur). The free ends of the screen arm 55 of each screen star 18 define an outer circumferential circle, in which the respective associated scrapers 17 in the (second) cleaning position shown in FIG. 3 just enter. Exactly this cleaning position is also shown in Fig. 1.

Due to the arcuate trajectory of the holder 16 describe the scrapers 17 on reaching the (first) cleaning position shown in FIG. 4 in relation to the screen hubs 54 tangentially directed way.

The cleaning device 15 is held on the star screen 10 on two support bridges 56, 57. These stand on lateral cheeks 58, 59 of the star screen 10 and vice versa are U-shaped. In this case, the front in the conveying direction support bridge 56 as a base to a cross member 60 which is mounted parallel to the cross member 39 and in the conveying direction shortly before the same under the longitudinal bars 41, 42. Correspondingly, a transverse strut 61 of the support bridge 57 extends directly below that in the conveying direction last crossbar 40 and is fixedly connected to this or the adjacent longitudinal beams 41, 42.

Bridge arms 62, 63, 64, 65 extend from the transverse struts 60, 61 except for the cheeks 58, 59. In order to stabilize and better absorb forces in the conveying direction, one wall each is provided between the bridge arms 62, 63 and 64, 65 66, 67 confiscated. The wall 66, 67 may also extend further in the conveying direction or against the conveying direction, as shown in FIGS. 1 to 4.

The walls 66, 67 do not extend completely down to the cheeks 58, 59. Rather, a side wall 68, 69 are provided in each of these spaces on both sides of the screen shafts 12-14. These extend in the conveying direction along all screen waves and thus prevent lateral slippage of the material to be screened from the star screen 10. The side walls 68, 69 may be obliquely directed, see Fig. 1, to form an upwardly flared funnel-shaped cross-section. Preferably, then the walls 66, 67 extend in cross-section not in the vertical direction, but also funnel-shaped but with upwardly decreasing cross-section, see also Fig. 1. Similarly, the bridge legs 62, 65 in the region of the walls 66, 67 are not vertical but diagonally.

The scrapers 17 are preferably formed substantially rectangular with a maximum extent in a plane transverse to the conveying direction. Alternatively, the scrapers 17 may be spoon-shaped, namely with a slightly wider Abstreiferfläche and a subsequent thereto and contrast somewhat narrower handle. It is expedient to have sharp lower and lateral edges of the wiper for carrying the material to be wiped off.

The scrapers 17 may be individually secured to the cross members 19. Preferred is an embodiment in which all scrapers of a cross member 19 are an integral part of a one-piece scraper formation or scraper mat. In this case, a web of the scraper formation is connected parallel to the respective cross member 19 with this. From the web, the individual scrapers 17 extend downward, see in particular Fig. 1. Web and scrapers 17 are integrally formed there.

Claims (13)

Star screen (10) with cleaning device (15),
wherein along a conveying direction a plurality of transverse to the conveying direction arranged sieve shafts (12, 13, 14) follow each with several screening stars,
wherein the screen stars (18) each have a plurality of screen arms (55),
wherein in each case a gap between the on the same screen shaft (12, 13, 14) adjacent screen stars (18) is provided,
wherein the cleaning device (15) on a holder (16) scraper (17) for entry into at least some of the interstices,
and wherein the holder (16) is movable between a starting position, in which the scrapers (17) do not enter into the intermediate spaces, and a first cleaning position, in which the scrapers (17) enter into the intermediate spaces,
characterized,
in that the holder (16) is movable into a second cleaning position, in which the wipers (17) make contact with the sieve arm arms (55). Star screen according to Claim 1, characterized in that the scrapers (17) in the second cleaning position make contact with the screen arms (55) of the screen stars (18), which are arranged on screen shafts (13) to the screen shafts (12), between whose screen stars (18) the scrapers (17) in the first cleaning position occur, respectively adjacent. Star screen according to claim 1 or further claims, characterized in that the second cleaning position of the first cleaning position is downstream in the conveying direction. Star screen according to claim 1 or further claims, characterized in that the scrapers (17), in particular free ends thereof, in the second cleaning position have contact with free ends of the screen arm arms (55). Star screen according to claim 1 or further claims, characterized in that each sieving star (18) defines a radial plane in which also the sieve arm (55) of this sieving star touching stripper (17). Star screen according to claim 1 or further claims, characterized in that the holder (16) with the scrapers (17) above the screen shafts (12, 13, 14) and is movable downward in the cleaning positions. Star screen according to claim 1 or further claims, characterized in that the holder (16) is movable with the scrapers (17) along an arcuate path of movement between the initial position and the first cleaning position and thereby passes the second cleaning position. Star screen according to claim 1 or further claims, characterized in that the holder (16) for the scrapers (17) preferably suspended above the screen shafts (12, 13, 14) on a parallelogram-like linkage (23) and along an arcuate, in particular quarter-circle path of movement is pivotable. Star screen according to claim 1 or further claims, characterized in that the scrapers (17) on transverse beams (19) are arranged, which extend parallel to the screen shafts (12, 13, 14), and that a plurality of cross member (19) part of the frame-like Halters (16) are. Star screen according to claim 1 or further claims, characterized in that the movement of the holder (16) takes place hydraulically, wherein preferably the movement of the holder (16) from a starting position into the cleaning positions by self-weight and the return movement of the holder (16) takes place hydraulically. Star screen according to claim 1 or further claims, characterized in that the movement of the scrapers (17) from the initial position into the second cleaning position takes place against the rotational movement of the screen stars (18). Star screen according to claim 1 or further claims, characterized in that for limiting the movement of the holder (16), in particular the lowering movement, a particular adjustable stop is provided. Star screen according to claim 1 or further claims, characterized in that the movement of the holder (16) substantially obliquely downward in the direction of the screen shafts (12, 13, 14), in particular such that the scrapers (17) with their free ends approximately tangentially to screen hubs (54) and in particular are up to this movable.

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