Screens, especially pressure screens

Abstract

The present invention provides a pressure screen or pressure screen device having screens (S1-S14), in particular an inlet (Z), and at least one axially separated receiving outlet (Ak) and rejection outlet (R). Screen elements (2, 2') are arranged in the inlet chambers (ZR) of the screens (S1-S14), and a rotor (3) is arranged in the inlet chambers (ZR) of the screen elements, radially separated and rotated by a drive (G). The rotor includes at least two rotor zones (A, B) axially between the inlet (Z) and the receiving outlet (Ak), rotating at different rotational speeds. Each rotor zone is assigned a corresponding screen basket zone (2A, 2B; 2'A, 2'B). The rotor zones can rotate in the same or opposite directions. The screens can be operated according to the inlet or outlet principle, in any combination as required.

Description

[Technical Field]

[0001] The present invention relates to a screen, in particular a pressure screen, and generally to a pressure screen device. This type of screen has an inlet and at least one receiving outlet and one rejecting outlet, each spaced axially from the inlet. Furthermore, the screen elements are arranged in the usual way, for example in the form of a screen basket, and the inlet chamber of the screen elements has a rotor spaced radially from the inlet chamber and rotated by a drive means. [Background technology]

[0002] European Patent No. 0404624B1 discloses a pressure screen device and a method for controlling a pressure screen. The pressure screen device includes an inlet and an axially spaced intake and rejection outlets. The pressure screen device further includes a screen basket, or a commonly referred to as a screen plate. A screen plate processor, a rotor blade structure, is provided radially spaced from the screen basket, and a baffle plate structure is provided radially spaced from the rotor blade. Both the baffle plate structure and the screen plate processor (rotor) feed the fiber suspension to the screen plate. Separate drives are connected to the rotor and the baffle plate processor, respectively. This allows the rotor and the baffle plate structure to be driven at their desired speeds. In this prior art, the rotor element directs the flow to the screen element or the screen basket, i.e., redirects the flow from an axial flow to a radial flow. The rotor element is effective over the entire axial length of the screen element. A second rotor blade structure with a different rotational speed is located downstream, with a separate drive, to achieve a cleaning effect on the screen element (screen basket) by applying pressure / suction to the surface of the screen element. This second rotor blade structure sweeps the entire axial length of the screen element. Although both rotor elements are located between the inlet and the receiving outlet, the individual rotor elements are connected radially one behind the other and sweep the entire height of the screen element (screen basket). This allows for different operating modes.

[0003] Furthermore, U.S. Patent Nos. 3,939,065, issued February 17, 1976, and 3,933,649, issued January 20, 1976, disclose a screening apparatus, in particular a pressure screening apparatus, including two conical, radially spaced screen drums, first and second. Thus, this prior art document shows a two-stage screening or separating apparatus having two conical screen members assigned to two independent drives.

[0004] German Patent No. 10206595A1 relates to a non-universal wood chip spreading device. German Patent No. 3347115C2 discloses a conical screen device for a spiral conveying centrifuge. German Utility Model No. 1637850U ​​discloses a screen drum for waste treatment. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to improve screening efficiency and reduce energy and operating costs. [Means for solving the problem]

[0006] According to the invention, a screen, in particular a pressure screen, is provided for this purpose, comprising an inlet, at least one receiving outlet and one rejecting outlet spaced apart in the axial direction, a screen member, and a rotor spaced apart radially therefrom and rotated in the inlet chamber of the screen member by a drive. In accordance with the concept according to the invention, the screen is constructed in such a way that the rotor comprises at least two downstream rotor regions axially between the inlet and the receiving outlet, the rotor regions rotating at different rotational speeds, and each rotor region is assigned to a corresponding screen member region.

[0007] This allows each rotor section to be tailored to the concentration and / or type of material being screened, achieving a significant improvement in the overall screening efficiency of the screen. Furthermore, having at least two rotor sections rotating at different rotational speeds allows for tailoring to the screening mass or material being screened, thereby reducing the energy and operating costs of such screening.

[0008] Further preferred embodiments of the present invention are set out in claims 2 to 25.

[0009] On the one hand, the rotor sections can rotate in the same direction but at different rotational speeds, and on the other hand, the rotor sections can rotate in opposite directions, allowing for further optimization and adjustment based on the properties of the material being screened.

[0010] In a preferred embodiment of the present invention, the inlet rotor section rotates slower than the reject or downstream rotor section. This allows the material to be screened to initially stay in the inlet section longer than in the subsequent reject or downstream rotor section. This allows the screening process of the material to be screened to be optimized and controlled accordingly. In this embodiment, the inlet rotor section rotates 10% to 60% slower, preferably between about 20% and 40%, than the reject or downstream rotor section.

[0011] Preferably, the screen element is configured essentially cylindrically, but can also be configured essentially conically, this depends in particular on the construction of the screen.

[0012] Preferably, the screen members have different diameters and the rotor regions also have different diameters to cooperate appropriately with the screen members having different diameters.

[0013] Preferably, the rotor blades in the rotor region are arranged at different distances from the wall of the screen element to set correspondingly different screening conditions. The distance between the rotor blades and the screen element is between 1.5 mm and 10 mm, preferably between 2.5 mm and 6.0 mm.

[0014] As can be seen from the drawing, the rotor blades in the rotor region within the inlet chamber may be positioned upstream of the screen member.

[0015] A preferred embodiment is characterized in that the direction of the received flow through the screen members is directed radially inward. Optionally, the flow passes through at least two screen members in different radial directions.

[0016] In particular, the at least two rotor sections may be configured in the form of different rotor structures, preferably comprising an open rotor structure, particularly for low consistency applications, and a closed drum structure, particularly for high consistency applications.

[0017] In a preferred construction of the screen, at least two rotor regions are assigned a common inlet and are provided with at least two separate receiving outlets spaced apart in the axial direction.

[0018] In a preferred embodiment of the invention, the drive for the rotor section comprises a gearing with at least two shaft outputs for different drives of the rotor section, which results in a screen with a small space requirement and a simple design.

[0019] Alternatively, the drive device includes at least two separate drives, each including an axial hollow shaft for passing a drive shaft for each of the other rotor sections.

[0020] Generally, one or more drives may be provided at the top of the screen and / or at the bottom of the screen.

[0021] In a preferred embodiment, the screen is configured in a configuration with more than two rotor sections spaced apart from one another, rotating at different speeds and / or with different directions of rotation, allowing for flexibility in adapting the operating environment and conditions to the properties of the material being screened.

[0022] In summary, the invention is based on the fundamental idea that the rotor comprises at least two rotor sections axially between the inlet and the receiving outlet, which rotor sections rotate at different rotational speeds in order to achieve an optimized adaptation to the screened material being processed, each of which is assigned to a corresponding screen element section.

[0023] Further details, features and advantages of the invention will become apparent from the following description of preferred, non-limiting embodiments with reference to the attached drawings. [Brief explanation of the drawings]

[0024] [Figure 1] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 2] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 3] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 4] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 4a] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 4b] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 5] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 6] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 7] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 8] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 9] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 10] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 11] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 12] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 13] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. [Figure 14] 1A to 1C are schematic cross-sectional views showing different embodiments of the essential idea of ​​the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] In the drawings, the same or similar parts are designated by the same reference numerals.

[0026] FIG. 1 shows a first construction of a screen S1 having a screen housing 1. An inlet Z for the material to be screened is located near the top of the screen housing 1. Axial distance away from the inlet Z is a receiving outlet Ak and a rejection outlet R, located near the bottom of the screen housing 1. A screen member 2, preferably in the form of a cylindrical screen basket, is located within the inlet chamber of the screen housing 1. A rotor, generally designated 3, is located radially away from the inlet Z. The rotor 3 includes a first rotor section, represented by a schematic rotor A, and a second rotor section, represented by a schematic rotor B. The drive for rotor A includes a motor A1, a pulley A2, and a drive shaft A3. The second rotor section, located downstream of the rejection outlet, represented by rotor B, has a drive including another motor B1, a pulley B2, and a drive shaft B3 configured as a hollow shaft. Thus, the embodiment of FIG. 1 includes a screen S1 with two separate drives, one for rotor section A and the other for rotor section B. The drive shaft B3 is formed as a hollow shaft and is mounted in a correspondingly suitable manner so as to be axially aligned with the drive shaft A3.

[0027] Arrows are used to indicate the direction of rotation of rotors A and B. The length of the arrows makes it clear that rotor section A on the inlet side rotates slower than rotor section B on the rejection outlet side, i.e., downstream side. Both rotor sections, i.e., rotors A and B, rotate in the same direction. Therefore, in the embodiment of screen S1 shown in Figure 1, separate drives are provided for rotor section A and rotor section B. Separate screen element sections 2A and 2B (screen basket sections) are assigned to rotor section A and rotor section B, respectively.

[0028] In contrast, in the embodiment shown diagrammatically in Figure 2 and also in the other Figures 2 to 11, a common drive motor M is provided, to which a common pulley arrangement RS is assigned. A gearing G is provided inserted into the common pulley arrangement RS, and this gearing G includes at least two shaft outputs (shown diagrammatically) for driving the rotor sections A and B. As shown in the embodiment of Figure 2, the two rotor sections A and B rotate in the region of the screen element 2 (screen basket) in the same direction but at different rotational speeds, as evidenced by the length of the arrows indicating the rotational movement.

[0029] In contrast, in the embodiment of screen S3 of Figure 3, rotor areas A and B rotate in opposite directions, with rotor area A rotating slower than rotor area B, as indicated by the arrows. All other details of this embodiment S3 essentially correspond to the embodiment of screen S2 of Figure 2.

[0030] Another alternative configuration of the screen, here generally designated S4, is shown in FIG. 4. In contrast to the previous figures, here the inlet Z is located near the bottom of the screen S4, while the rejection outlet is located near the top of the screen S4, and the receiving outlet Ak is located approximately axially centrally between the rejection outlet R and the inlet Z. Furthermore, this screen S4 has a heavy waste discharge port 5. Furthermore, the embodiment S4 shown in FIG. 4 includes a combination of different rotor design variants: a drum design for high-concentration applications and an open rotor design for low-concentration applications. Further details of the drum design for high-concentration applications are shown diagrammatically in FIG. 4a. The drum design has a cylindrical rotor body 10, with rotor blades 11 fixed to the outer wall of the drum-shaped rotor body. In FIG. 4, for example, rotor area A has a drum design.

[0031] Figure 4b shows an open rotor structure intended for low concentration applications, comprising rotor region B, i.e., rotor B. The open rotor structure of Figure 4b includes a centrally located rotor body 12 to which rotor blades 13 are attached by rotor blade attachments 14. These rotor blades 13 sweep over the inner surface of screen member 2, similar to Figure 4a.

[0032] 5 shows an embodiment of the screen S5 in which the rotor sections, i.e., rotors A and B, have different rotational speeds, as achieved in the previous embodiment by separate drives or gearing G. In the embodiment of the screen S5, the screen element 2 comprises two screen elements 2a and 2b, to which separate receiving inlets Ak1 and Ak2 are assigned, respectively.

[0033] FIG. 6 shows a screen generally designated by the reference numeral S6. The basic structure and configuration are essentially the same as those of the screen S2 shown in FIG. 2. However, the screen elements 2a' and 2b here may have different diameters and / or the rotor regions A and B may also have different diameters. The assigned screen element regions are designated by the reference numerals 2'A and 2'B. By changing the diameters of the screen elements 2a' and 2b' and / or the diameters of the rotor regions A and B, corresponding different screening conditions can be set.

[0034] FIG. 7 shows an embodiment in which the screen S7 has rotor sections A and B with different diameters, while the diameter of the screen element 2 in the form of a screen basket remains the same. This allows for different distances between the screen element 2 and the outer surfaces of the rotor sections A and B. In the embodiment of FIG. 7, the small-diameter rotor section A is located closer to the inlet side, while the large-diameter rotor section B is located closer to the receiving side. Here, too, the screening conditions between rotor sections A and B can be adapted to the material to be sorted. Of course, the small-diameter and large-diameter rotor sections can also be selected in the reverse order from that shown in FIG. 7. The distance between the rotor blades 13 and the screen element 7 is between 1.5 mm and 10 mm, preferably between 2.5 mm and 6.0 mm. A special embodiment is characterized in that the rotor blades of the inlet rotor section (A) are 0% to 30% closer to the wall of the screen element (2, 2', 2a) than the rotor blades of the rejection or downstream rotor section.

[0035] FIG. 8 shows a screen S8 which is based on the basic structure of the screen S5 shown in FIG. 5, but which has screen members 2a and 2b with different diameters as in the embodiment of FIG.

[0036] FIG. 9 shows a screen, generally designated S9, which is provided with a number of rotor sections A-F, which are shown only diagrammatically. These rotor sections A-F rotate at different rotational speeds or in different rotational directions. Otherwise, the basic structure of the screen S9 corresponds to the screens previously shown and described. Each rotor section is assigned a separate screen element section 2A, 2B (screen element section ACE; BDF).

[0037] The screen shown in its entirety in Figure 10 has a basic structure that essentially corresponds to that of Figure 1, but the drive motor A1 is located near the top of the screen S10, thereby avoiding the one-sided compound shaft / hollow shaft drive through the base of the pressure screen housing as shown in Figure 1.

[0038] 11 shows a schematic view of a screen S11 provided with conically shaped rotor sections A' and B'. Similarly, the screen element 2' is also shaped in a corresponding cone and is assigned screen element sections 2'A and 2'B. The drives for the rotor sections are configured in accordance with the previously described embodiments.

[0039] Finally, FIG. 12 shows a screen S12 which is similar in its basic structure to the screen S10 of FIG. 10, but it is now made clearer that the screen member in the form of a screen basket 2 is also driven in rotation by a motor A2 located at the top of the screen housing 1.

[0040] Figure 13 shows screen S13, which is similar to screen S10 in terms of the basic structure of the drive arrangement. However, rotor A is arranged in the outer region of screen element area A2. As a result, the suspension to be screened flows from the outer diameter of screen element 2 into the internal space of screen element 2. The inflow direction in this configuration is centripetal, so this screen area works according to the inflow principle. The incoming flow of screen element 2A is now the inlet flow of screen element 2B, and is subsequently processed radially outward through screen element 2B in rotor area B (outflow principle). The screening material to be processed is thus processed in interdependent stages.

[0041] Figure 14 shows a screen S14 in which both rotor sections A and B operate according to the inflow principle. Here, the inlet Z originates from the outer diameter of the screen element 2. Each rotor section is driven at a different rotor rotational speed by the shaft power assigned to the respective rotor section. Figure 13 shows that rotor B is at a greater distance to the screen element 2 than rotor A.

[0042] The screen elements can be of various constructions: profiled bars, ring-shaped structures, slotted screen elements 2, perforated metal sheet structures with slits, round holes, or other opening shapes. Fabrics can also be used as screen elements.

[0043] It goes without saying that the present invention is not limited to the preferred embodiment described and shown above, but that numerous variations and modifications, and in particular combinations of preferred embodiments, are possible. However, all preferred embodiments and all variants of the embodiments have in common that they have at least two different rotor areas A, B which preferably rotate at different rotational speeds, and that the different rotor areas A, B are respectively assigned separate screen member areas 2A, 2B, 2'A, 2'B. [Explanation of symbols]

[0044] S1~S14 Whole screen 1 Screen Housing 2. Screen member in the form of a screen basket 2A, 2B Screen member area 2' The screen member of FIG. 11 configured in a conical shape 2'A, 2'B Screen member area 3 rotors 5. Heavy waste outlet 10 Drum-structure rotor body (Fig. 4a) 12 Open rotor structure (Fig. 4b) 13 Rotor blade / rotor blade attachment 14 Rotor blade attachment M Common drive motor for Figures 2 to 11 G Gearing A First rotor region or rotor (inlet side) B. Second rotor area or rotor (receiving side) Ak Receptor Exit R exclusion outlet Z entrance ZR inlet chamber RS pulley structure (overall) The drive for rotor A includes a motor A1, a pulley A2, and a drive shaft A3. The drive of the rotor B includes a motor B1, a pulley B2, and a drive shaft B3 configured as a hollow shaft.

Claims

1. 1. A screen, in particular a pressure screen, comprising an inlet (Z), at least one receiving outlet (Ak) and a rejection outlet (R) spaced apart in the axial direction, a screen element (2, 2'), and a rotor (3) spaced apart in the radial direction relative thereto and rotated in an inlet chamber (ZR) of said screen element (2, 2') by a drive, characterized in that the rotor (3) comprises at least two downstream rotor areas (A, B) axially between the inlet (Z) and the receiving outlet (Ak), the rotor areas rotating at different rotational speeds, and each of the rotor areas being assigned to a corresponding screen element area (2A, 2B; 2'A, 2'B).

2. 2. A screen according to claim 1, characterized in that the rotor areas (A, B) rotate in the same direction.

3. 2. A screen according to claim 1 (FIG. 3), characterized in that the rotor areas (A, B) rotate in opposite directions.

4. 4. A screen according to claim 1, wherein the rotor section (A) on the inlet side rotates slower than the rotor section (B) on the rejection outlet side, i.e., downstream side (FIGS. 2 and 4).

5. 5. A screen according to claim 4, characterized in that the rotor section (A) on the inlet side rotates slower than the rotor section (B) on the rejection outlet side or downstream side by 10% to 60%, preferably between about 20% and 40%.

6. 6. A screen according to claim 1, wherein the rotor regions (A, B) are essentially cylindrical in design.

7. 6. A screen according to any one of claims 1 to 5, characterized in that the screen elements (2, 2') are of essentially cylindrical construction.

8. 6. Screen according to any one of claims 1 to 5 (Fig. 11), characterized in that the rotor areas (A, B) are essentially conical in design.

9. 9. Screen according to claim 8 (FIG. 11), characterized in that the screen element (2') is configured essentially conically.

10. 10. A screen according to any one of claims 1 to 9 (Fig. 6), characterized in that the screen elements (2a) have different diameters.

11. 11. A screen according to any one of claims 1 to 10 (Fig. 6), characterized in that the rotor areas (A, B) have different diameters and cooperate appropriately with screen elements (2a) having different diameters.

12. 12. A screen according to any one of claims 1 to 11, characterized in that the rotor blades of the rotor sections (A, B) are arranged at different distances from the wall of the screen element (2, 2', 2a).

13. 13. A screen according to any one of claims 1 to 12, characterized in that the distance between the rotor blades (13) and the screen element (2) is between 1.5 mm and 10 mm, preferably between 2.5 mm and 6.0 mm.

14. 14. A screen according to any one of claims 1 to 13, characterized in that the rotor blades of the rotor section (A) on the inlet side are 0% to 30% closer to the wall of the screen element (2, 2', 2a) than the rotor blades of the rotor section (B) on the rejection outlet side, i.e. downstream side.

15. 15. A screen according to any one of claims 12 to 14, characterized in that the rotor blades (13) of the rotor zones (A, B) in the inlet chamber (ZR) are arranged upstream of the screen elements (A, B).

16. 16. A screen according to any one of claims 1 to 15 (Fig. 1), characterized in that the direction of the receiving flow through the screen elements (A, B) is directed radially outwards.

17. 16. A screen according to any one of claims 1 to 15 (Fig. 14), characterized in that the direction of the receiving flow through the screen elements (A, B) is directed radially inwards.

18. 18. A screen according to any one of claims 1 to 17 (Fig. 13), characterized in that the flow passes through at least two of the screen elements (A, B) in different radial directions.

19. 19. A screen according to any one of claims 1 to 18 (Fig. 4), characterized in that at least two of the rotor regions (A, B) are configured in the form of different rotor structures.

20. 20. The screen according to any one of claims 1 to 19, characterized in that the rotor area (B) comprises an open rotor structure (12), preferably for low consistency applications, and a closed drum structure (10), preferably for high consistency applications (Figure 4).

21. 21. A screen according to any one of claims 1 to 20, characterized in that at least two of the rotor regions (A, B) are assigned a common inlet (Z) and at least two further receiving outlets (Ak1, Ak2) arranged axially at a distance.

22. 22. A screen according to any one of the preceding claims, characterized in that the drive device comprises a gearing (G) with at least two shaft outputs for driving the rotor sections (A, B).

23. 23. Screen according to any one of claims 1 to 22 (Figure 1), characterized in that the drive device comprises at least two separate drives.

24. 23. A screen according to claim 22, characterized in that the drive device comprises an axial hollow shaft (B3) for passing a drive shaft for each other rotor section (B, A).

25. 25. A screen according to any one of claims 1 to 24 (Figs. 10, 11), characterized in that a drive (A1) is provided at the top of the screen (S10) and / or at the bottom of the screen (S10).

26. 26. A screen according to any one of claims 1 to 25, in a configuration with more than two rotor areas (A to F) spaced apart from one another, characterized in that they rotate at different speeds and / or have different directions of rotation (Fig. 9).

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