Abstract
A screening device for fibrous stock suspensions of the paper industry includes at least two separate screening baskets which are connected axially behind one another in the interior of a reinforcing device in the form of a back-up cylinder. A variable-diameter intermediate ring is arranged between the screening baskets. The reinforcing device has a cover part and a bottom part. By way of axial tensile force loading of the arrangement, the intermediate ring is loaded so as to bear radially in the circumferential direction in a gap-free manner against the associated axial ends or screening basket flanges of the screening baskets. The screening baskets are then clamped and fixed in a centrally positioned manner by the intermediate ring in cooperation with the end-side flange of the reinforcing device, the cover part, the bottom part and the intermediate ring.
Claims
1. A screening device for fibrous suspensions in the paper industry, comprising: at least two separate, substantially cylindrical screening baskets arranged sequentially in an axial direction, each screening basket forming a screening surface, a reinforcing device constructed as a support sleeve and having an end flange at one axial end, with the reinforcing device surrounding the screening basket with a radial spacing therebetween, a variable-diameter intermediate ring interposed between the at least two screening baskets, a cover part and a bottom part, wherein the at least two screening baskets in cooperation with the end flange of the reinforcing device, the cover part, the bottom part and the intermediate ring are centrically placed, clamped and fixed inside the reinforcing device.
2. The screening device of claim 1, wherein the variable-diameter intermediate ring is split.
3. The screening device, of claim 1, wherein the variable-diameter intermediate ring is slotted.
4. The screening device of claim 1, wherein the variable-diameter intermediate ring is formed by an elastomer ring.
5. The screening device of claim 1, wherein the cover part and the bottom part in cooperation with ends of the at least two screening baskets form in each case a rotation-locked unit.
6. The screening device of claim 5, wherein the rotation-locked unit is constructed as a pin and groove arrangement.
7. The screening device of claim 1, wherein the intermediate ring and ends of the at least two screening baskets form a rotation-locked unit.
8. The screening device of claim 6, wherein the rotation-locked unit is constructed as a pin and groove arrangement.
9. The screening device of claim 1, wherein the cover part, the bottom part and the intermediate ring form a non-positive connection with the at least two screening baskets by way of a spline connection.
10. The screening device of claim 9, wherein the spline connection is formed as a conical seat connection.
11. The screening device of claim 1, wherein the screening device is assembled by arranging in the reinforcing device a first of the at least two screening baskets which rests on the bottom part, by placing the variable-diameter intermediate ring on an upper axial end of the first screening basket, by placing a second of the at least two screening baskets on the variable-diameter intermediate ring, and by placing the cover part on an upper axial end of the second screening basket, wherein when an axial clamping force is applied to the assembled screening device, the intermediate ring is spread open in a circumferential direction and bears gap-free against the axial ends of the at least two screening baskets in the radial direction.
12. The screening device of claim 1, wherein the at least two screening baskets have different characteristics selected from slot width, slot shape, partitions, profile depth, profile size and profile slope.
Description
BRIEF DESCRIPTION OF THE DRAWING
(1) The invention will now be explained in more detail below with reference to preferred embodiments illustrated in the appended drawing, which shows in:
(2) FIG. 1 a schematic structural drawing of the screening device according to the invention, in half section and transverse view;
(3) FIGS. 2a and 2b schematic views for illustrating the application of the axial clamping force;
(4) FIGS. 3a and 3b schematic views for illustrating the function of the intermediate ring before and after application of the clamping force in the screening device according to the invention;
(5) FIGS. 4a and 4b schematic views in association with FIGS. 3a and 3b;
(6) FIGS. 5a and 5b a sectional view and a schematic perspective detailed view showing a rotation lock in the upper region of the screening device;
(7) FIGS. 6a and 6b a schematic sectional view and cut-away perspective detailed view showing a rotation lock in the intermediate region of an intermediate ring;
(8) FIGS. 7a and 7b a schematic sectional view and a perspective view illustrating a rotation lock at the bottom region of the screening device according to the invention; and
(9) FIGS. 8a and 8b schematic views illustrating an alternative embodiment of a variable-diameter intermediate ring.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
(10) Identical or similar parts in the figures of the drawing are given the same reference numerals. Furthermore, the representations do not represent limiting embodiments.
(11) Referring now to FIG. 1, the essential components of a screening device according to the invention designated with the reference numeral 1 will now be briefly explained. The screening device 1 includes a reinforcing device 2 in the form of a support sleeve or backup cylinder. In the illustrated embodiment, two separate screening baskets 3, 4 are arranged axially one behind the other in the interior of this reinforcing device 2. A variable-diameter intermediate ring 5, which cooperates with the respective front ends of the two abutting screening baskets 3, 4 in a manner to be described later, is arranged between the two screening baskets 3, 4. A bottom part 6, into which an end-side axial end of the screening basket 4 is inserted by way of a spline connection, preferably a conical seat connection 7, is provided in the lower region of the screening device 1. At the upper end in FIG. 1, the reinforcing device 2 is closed off by a cover part 8 which, on the one hand, cooperates via a non-positive connection in the form of a spline connection groove formed as a conical seat connection 9 with an upper end of the screening basket 3. On the other hand, the cover part 8 is secured to the reinforcing device 2 via clamping screws 12. An intermediate ring 5 is arranged between the reinforcing device 2 and the two axially facing ends of the two screening baskets 3, 4. To assemble such a screening device having the overall designation 1, a first screening basket 4 is inserted into the interior space formed by the reinforcing device 2 in the form of a supporting cylinder, such that the lower axial end of the screening basket 4 rests on the bottom part 6 via the non-positive connection in the form of a conical seat connection 7, for example, with an interference fit. The variable-diameter intermediate ring 5 is then placed on the upper axial end of the first screening basket 4. The second screening basket 3 is then arranged above the intermediate ring 5 in axial alignment with the first screening basket 4 and cooperates with the intermediate ring 5 via a non-positive connection, preferably a spline connection 11. Lastly, the cover part 8 is then attached on the upper axial end of the second screening basket 3 by way of the non-positive conical seat connection 9. With the aid of clamping screws 12, an axial clamping force is then applied to the overall arrangement composed of the cover part 8, the two screening baskets 3, 4, the interposed intermediate ring 5 and the bottom part 6.
(12) The application of the clamping force between the cover part 8, the reinforcing device 2 in the form of a support sleeve and the second screening basket 3 is illustrated schematically with reference to FIGS. 2a and 2b. FIG. 2a schematically illustrates the conditions, when the cover part 8 rests loosely on the conical seat connection 9. As indicated in FIG. 2a, for example, a distance a.sub.1 exists in this state. As illustrated in FIG. 2b, this distance is substantially smaller after the clamping screws 12 are tightened and is designated therein by a.sub.2.
(13) The operation of the intermediate ring 10 is illustrated schematically with reference to FIGS. 3a and 3b. FIG. 3a in association with FIG. 2a shows a schematic diagram where the intermediate ring 5 has, for example a distance b.sub.1, from the interior wall of the reinforcing device 2. The two axial ends of the screening baskets 3, 4 have according to FIG. 3a for example a distance a.sub.2. FIG. 3b shows the state when an axial clamping force is applied in accordance with FIG. 2a. When this axial clamping force is applied, the axial distance between the two baskets 3, 4 becomes smaller and decreases to a.sub.3. The intermediate ring 10 is pressed directly against the interior wall of the reinforcing device 2 in the form of a support sleeve, and the distance previously designated in FIG. 3a with b.sub.1 is canceled. In this case, the compressive forces can then be transferred to the reinforcing device 2 via the axial ends (end flanges) of the screening baskets 3, 4, thereby increasing and enhancing the overall stability to the screening device 1.
(14) FIGS. 4a and 4b schematically illustrate the situation in a plan view. The intermediate ring 5 is in the illustrated, preferred embodiment designed with a variable diameter in that it is divided or slotted, meaning that this variable-diameter intermediate ring 5 is not closed at its circumferential ends, but has a spacing c.sub.1 in the circumferential direction.
(15) As seen from FIG. 4b in association with FIG. 3b, the intermediate ring 5 is spread apart in the circumferential direction by the axial clamping force application in such a way, the spacing between the circumferential ends of the split intermediate ring 5 is increased to c.sub.2 with respect to FIG. 4a. At the same time, the spacing b.sub.1 between the interior wall of the reinforcing device 2 is cancelled due to the effect of the clamping force.
(16) As can inferred from FIGS. 2a to 4b, the variable-diameter intermediate ring 5 is arranged between the axially opposite two ends of the two screening baskets 3, 4 in the interior of the reinforcing device 2 in the form of a support sleeve in such a manner that the screening baskets 3, 4 in cooperation with an end flange 13 of the reinforcing device 2 in the form of a support sleeve, the cover part 8, the base part 6 and the variable-diameter intermediate ring 10 are centrally positioned, clamped and fixed.
(17) In the screening device according to the invention, when the axial clamping force is applied with the clamping screws 12, the two screening baskets 3, 4 are effectively centered one after the other, with these two screening baskets 3, 4 at the same time being firmly clamped in cooperation with the variable-diameter intermediate ring 5 against each other and against the interior wall of the reinforcing device 2.
(18) FIGS. 5a and 5b illustrate an optional for rotation lock 14, which is in the illustrated example designed as a pin and groove arrangement 15. This rotation lock 14 prevents a relative rotation between the cover part 8 and the second screening basket 3.
(19) FIGS. 6a and 6b show a rotation lock 16 which is also preferably designed in the form of a pin and groove arrangement 17 that is effective between the two axially abutting ends of the two screening baskets 3, 4, and effectively prevents a rotation of the screening baskets 3, 4 relative to each other.
(20) FIGS. 7a and 7b illustrate a rotation lock 18 optionally provided at the bottom, which is preferably also designed as a pin and groove arrangement 19 and effectively prevents a relative rotation between the first screening basket 4 and the bottom part 6.
(21) FIGS. 8a and 8b lastly illustrate an alternative embodiment of a variable-diameter intermediate ring 5, which is designed as an elastomer ring 20. The elastomer ring 20 has an uninterrupted or continuous configuration and is deformed and pressed, starting from the loosely mounted state according to FIG. 8a, under the action of the applied axial clamping force according to FIG. 8b, so that even in the state shown in FIG. 8b there is no gap between the interior wall of the reinforcing device 2 and the corresponding axial ends or the end flanges of the two screening baskets 3, 4.
