NL8700290A - ROTATING SCREENING DEVICE WITH A NUMBER OF SCREEN SURFACES, EACH OF WHICH ARE DIVIDED INTO A NUMBER OF CONCENTRIC RINGS WITH REVERSIBLE, CONTINUOUSLY ANGLE SPEED. - Google Patents

Abstract

The invention relates to rotatable sieving apparatus for separating a mixture of at least one fine and one coarse component, comprising a number of sieving-surface (1,2) arranged on the same rotatable shaft (5) one above another and of which at least the outermost ones have the form of a conical mantle the apex of which is directed downward and in which one or more conical collecting vessels for the fine components are arranged under the sieving-surfaces, in which a conical divider (26)with an upwardly directed apex is arranged in the centre of each sieving-surface and in which the supply means for the mixture to be separated is located in the vincinity of the centre with the aid of a height-adjustable inlet-pipe arranged above the conical divider and the diameter of which inlet-pipe is equal to the diameter of the base of the conical divider. This type of sieving apparatus has as special characteristic that each sieving-surface is subdivided into an annular centre portion(1) in the form of a conical mantle-surface with an upwardly directed apex which follows up the divider(26) radially and with a reversible direction-of-rotation (d1) and an independent continuously-regulatable angular-velocity(w1) and a number of concentric members (2) arraranged to extend radially outward one outside of another each having the form of a truncated conical mantle the apexes of which are directed downward and each of which has a reversible direction-of-rotation(d2,dn) and an independent continuously regulatable angular-velocity(w2dn).

Description

* -1- 87202

Short designation: Rotary sieve device with a number of sieve surfaces, each of which is divided into a number of concentric rings with a reversible, continuously adjustable angular speed.

The invention relates to a rotary screen device according to the preamble of claim 1.

A rotary sieving device of this kind is known from NL-B-179.709, which can already achieve a good sieving effect with a reasonable sieving surface at a reasonable capacity. However, if the capacity is increased too much, the sieving effect deteriorates in percentage, then applying it. of a second underlying sieve surface to maintain the same good sieving effect, however, this gives a more complicated, larger and more expensive sieve arrangement.

The object of the invention is to provide a sieve device of the type described in the preamble, with which the capacity can be increased considerably while retaining the good sieve effect, while still obtaining a less complicated, smaller and cheaper sieve device. than with a number of sieve surfaces lying one above the other.

This object is achieved according to the invention by the measures indicated in the characterizing part of claim 1. With this, capacity increases of up to 50% can be achieved for some products while retaining the same sieve quality.

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Preferred embodiments of the invention are described in the subclaims.

It is noted that from DE-B-440.697 AD 1925 a rotating flat sieve device is known with two flat sieve surfaces lying one above the other, namely an upper circular and a lower annular. The product to be sieved is thrown off the upper sieve, impacts a surrounding cylindrical baffle and then falls on the lower annular screen, which is driven at a lower angular velocity than the top screen, however both angular velocities are constant and are derived from the same central drive shaft. unfavorable for the product, such as, for example, fodder in pellets, as this can break or crumble undesirably. Furthermore, the screening speeds cannot be adapted to the specific product requirements, so that the screening effect and capacity are limited.

The invention will now be further elucidated with reference to the accompanying schematic drawing, which shows a vertical, axial cross-section over an exemplary embodiment of a single-deck sieve device according to the invention.

According to the drawing, the sieve device comprises a central conical jacket-shaped sieve surface 1, the non-perforated tip of the cone of which faces upwards, and an outer truncated cone-jacket-shaped sieve surface 2, the imaginary tip of the cone of which faces downwards. avoid both sieve parts overlapping p 7 fva: r- f>.

The central sieve surface 1 over a short radial distance the outer sieve surface 2. The sieve surface 1 is supported by a spoke wheel 3 with radial spokes 4 and a hub 4, which is mounted on a generally central, central drive shaft 5. This shaft 5 is rotatably mounted in an inner bearing structure 6, which in turn is rotatably mounted in an outer bearing structure 7, which is fixedly mounted in the frame 8 of the sieve device. The central shaft 5 can be driven in the first place via a at the bottom end, drawn with solid lines / gearbox 9, which is coupled with an electric motor (not shown). As an alternative, the shaft 5 can be driven by means of a drive wheel 10 drawn with thin lines, which with its own hub 11 instead of the gearbox 9 15 is mounted on the shaft 5. On the rim 12 of this wheel 10 a friction wheel 13 with substantially vertical shaft 14 engages, of which the (not Shown) element The electric drive motor is accommodated in the protective box 15. Both the direction of rotation rl and the angular speed wl of the shaft 5 can be reversed or steplessly regulated with the respective electric motor.

The outer sieve surface 2 is supported by a spoke wheel 16 with a hub 17 which is again mounted on the inner bearing structure 6. On the outer circumference, this spoke wheel 16 has a rim 17, on which the friction wheel 18 with substantially vertical shaft engages, usually a rubber pneumatic tire or the like, which is driven by the electric / 0 0 c $ u.

1 «1 -4- motor 19. This motor 19 is suspended with a pivot arm 20 from a pivot shaft 21 to press the wheel 18 against the rim 17. Again the rotation direction r2 and the angular speed w2 of the electric motor 19 are reversed Éj or are continuously adjusted.

The sieve surfaces 1 and 2 are housed in a box 22 with a detachable top cover 23 and a central feed tube 24 for the product to be sieved. At the bottom end of the tube 24, a height-adjustable sliding sleeve 25 is arranged to the size of the annular outlet - gap between the non-perforated middle section or the distributor 26 of the sieve surface 1 and the bottom end of the sliding sleeve 25 can be infinitely adjusted. The sliding sleeve 25 and the distributor 26 have an essentially equal diameter, and the box 22 has a central bottom outlet 27 for the coarse component of the product to be sieved, as well as a side outlet 28 for the sieved fine component of the product to be sieved. The operation of this sieving device is as follows: The mixture of the coarse and the fine component to be separated is supplied through the supply tube 24 and the sliding sleeve 25, flows on the distributor 26 and through the outlet gap between this distributor 26 and the mouth of the sliding sleeve 25 on the central sieve surface 1, which rotates in one direction at an angular velocity w1. Under the influence of the centrifugal, gravity and friction forces with the sieve surface, the product moves approximately with a flow of substantially e λ. -a. ^ s ", f: 1 * VU u -5- involutive flow lines downwardly to the outer edge of the sieve surface 1. After this, the product comes the inner edge of the outer sieve surface 2, which for example rotates at a lower angular velocity w2, whereby it comes to a standstill for a moment. Then 5 moves in the opposite direction upwards to and over the outer edge of the latter screen surface. During this displacement over both screen surfaces, the fine component is sieved out and is discharged through the cutting outlet 28, while the coarse component is the central outlet 27 is discharged.

If the outer sieve surface 2 rotates in the same direction as the inner sieve surface 1, there is no reversal of direction but a delay takes place at the transition between the two sieve surfaces 1 and 2.

The invention is not limited to the illustrated and described exemplary embodiment, but extends to all variants thereof. More than two sieve surfaces can be present in the radial direction, while a number of these sieve surfaces can also be arranged one above the other in the vertical direction.

£ * 7 Λ Λ Λ Λ f? ί \ :. : 1

Claims (10)

1. Screening device for separating a mixture from at least one coarse and one fine component, consisting of a number of screen surfaces rotatable on top of one another and rotatable about the same axis of rotation, at least the outermost of which have the shape of a hollow cone jacket pointing downwards, wherein one or more collecting vessels for the fine components are arranged under the sieve surfaces, and in the center of each sieve surface is arranged a conical distributor with an upwardly directed point and the feed of the mixture to be separated is placed in the vicinity of the center using an inlet sleeve adjustable in height direction above the conical distributor, the diameter of which is equal to the diameter of the base of the distributor cone, characterized in that each sieve surface is divided into an annular central section (1), in the shape of a conical mantle surface with an upwardly directed point, which follows radially on the distributor (26), with reversible rotation orientation (dl) and independently continuously adjustable angular velocity (wl), and a plurality of concentric annular radially outwardly directed portions (2), each of which has the shape of a truncated conical jacket with a downwardly pointed tip, each have a reversible direction of rotation (d2, dn) and independently controllable angular velocity (w2 wn). 2. Screening device according to claim 1, characterized in that there are 8? F v; -7- an annular outer section (2) with reversible direction of rotation (d2) and independently continuously adjustable angular velocity (w2) is provided. Screening device according to claim 1 or 2, characterized in that the annular outer part (2) has a cylindrical drive surface (17) on which a friction wheel drive (18-21} engages. Screening device according to one or more of claims 1 to 3, characterized in that the annular central section (1) has a central drive with the aid of a central shaft (5). Screening device according to one or more of claims 1 to 4, characterized in that the central shaft (5) is driven by means of a gear wheel (S). Screening device according to one or more of claims 1 to 5, characterized in that the central shaft (5) is provided with the aid of a concentric drive wheel (10, 11) with a cylindrical drive surface (12) and an engaging thereon friction wheel drive (13-15) is driven. Screening device according to one or more of claims 1 to 6, 20, characterized in that the annular central section (1) and the annular outer section (2) are driven in opposite directions of rotation (r1, r2). Screening device according to one or more of claims 1 to 7, characterized in that the annular central section (1) and the annular outer section (2) are driven in the same direction of rotation (r1 or r2). Screening device as claimed in one or more of the claims 1-8, £ 7 c; ? G -8- fc Ί characterized in that the annular central section (1) is driven at a greater angular velocity (wl) than the angular velocity (w2) of the annular outer section (2). Screening device according to one or more of claims 1 to 9, 5, characterized in that the annular central section (1) overlaps the annular outer section (2) by part of its radial dimension. 8700290