ROTARY PRESSURE FILTER

Abstract

A rotary pressure filter suitable for use in treatment of one or more of medical products or foodstuffs, the rotary pressure filter. The rotary pressure filter comprises a filter drum that can be rotated about an axis of rotation. The rotary pressure filter comprises a plurality of filter cells arranged along an outer circumference of the filter drum, with a housing surrounding the filter drum. A process space is formed between the filter drum and the housing. The rotary pressure filter comprises at least one separating element dividing the process space into a plurality of treatment zones. At least one treatment zone is associated with a housing connector via which one or more of fluid or suspension can be introduced into the respective treatment zone.

Claims

1. A rotary pressure filter suitable for use in treatment of one or more of medical products or foodstuffs, the rotary pressure filter comprising: a filter drum that can be rotated about an axis of rotation; a plurality of filter cells arranged along an outer circumference of the filter drum; a housing surrounding the filter drum, wherein a process space is formed between the filter drum and the housing; and at least one separating element dividing the process space into a plurality of treatment zones, wherein at least one treatment zone is associated with a housing connector via which one or more of a fluid or a suspension can be introduced into the respective treatment zone, wherein the treatment zones are separated from one another such that the one or more of the fluid or the suspension is substantially prevented from passing from a first treatment zone into a second treatment zone that is adjacent to the first treatment zone according to a rotation of the filter drum, wherein the at least one separating element is configured to prevent a permanent accumulation of fluid in a region of the separating element, wherein the filter drum is sealed relative to the housing such that the one or more of the fluid or the suspension from at least one treatment zone is substantially prevented from exiting the at least one treatment zone other than through filter cells located in the treatment zone, and such that a permanent accumulation of the one or more of the fluid or the suspension in a region of a transition between the filter drum and the housing is prevented, and wherein a seal between the filter drum and the housing comprises a resilient hollow element that can be filled with a second fluid and that is designed to close a gap between the hollow element and the housing by filling the hollow element.

2. The rotary pressure filter of claim 1, wherein a sealing strip is associated with the hollow element and is arranged adjacent to it at the gap to be closed, wherein the sealing strip comprises a polytetrafluoroethylene (PTFE) material.

3. The rotary pressure filter of claim 1, wherein a cleaning rail is provided on the filter drum such that the cleaning rail rotates together with the filter drum, and wherein a plurality of nozzles are arranged along the cleaning rail.

4. The rotary pressure filter of claim 1, wherein a sliding element is associated with the hollow element which is arranged between the hollow element and a component of the rotary pressure filter that can be displaced relative to said hollow element.

5. The rotary pressure filter of claim 4, wherein the sliding element is secured to a same component to which the hollow element is also secured.

6. The rotary pressure filter of claim 2, wherein at least one of the hollow element, the sealing strip, and the sliding element is annular.

7. The rotary pressure filter of claim 6, wherein at least one of the hollow element, the sealing strip, and the sliding element is arranged substantially concentrically to the axis of rotation of the filter drum.

8. The rotary pressure filter of claim 1, wherein components that form the seal between the filter drum and the housing are also the components that form a seal between the separating elements and the housing.

9. The rotary pressure filter of claim 1, wherein the rotary pressure filter further comprises a control head arranged radially inwards relative to the filter drum and via which the fluid which has passed through the filter cells in a particular treatment zone leaves the rotary pressure filter, the control head being divided by control head separating elements into a plurality of discharge zones, the plurality of discharge zones abutting the filter drum and the control head such that the discharge zones are fluidically sealed with respect to one another, wherein a second hollow element that can be filled with a third fluid is arranged in a direction parallel to the axis of rotation of the filter drum with respect to one of the control head separating elements, wherein the second hollow element is designed to close a gap between the respective hollow element and the one of the control head separating elements by filling the second hollow element with the third fluid.

10. The rotary pressure filter of claim 9, wherein a sealing strip is associated with the second hollow element adjacent to the one of the control head separating elements, wherein the sealing strip can be arranged adjacent to the second hollow element at the gap between the second hollow element and the one of the control head separating elements.

11. The rotary pressure filter of claim 1, wherein a filter unit is arranged in a filter cell wherein the filter unit carries a filter cloth designed to retain, from the suspension to be filtered which reaches the filter cloth, solids above a size defined by the filter cloth and to allow the fluids to pass through, the filter cloth and a frame of the filter unit being one or more of (A) produced as separate components and being interconnected using a joining process.

12. The rotary pressure filter of claim 9, further comprising a second containment, on the control head of the rotary pressure filter, for bearing shields.

13. The rotary pressure filter of claim 11, wherein the filter unit comprises a seal extending at least partially around the frame of the filter cell, wherein the seal extending at least partially around the frame is configured to seal a gap between the filter cell and the filter unit arranged therein.

14. The rotary pressure filter of claim 11, wherein the filter unit is removable from the filter cell.

15. The rotary pressure filter of claim 1, further comprising housing connectors connected to and welded to the housing, wherein the one or more of the suspension or the fluid can be introduced into or removed from the process space via the housing connectors.

16. The rotary pressure filter of claim 1, wherein the resilient hollow element is arranged adjacent to all of the separating elements.

17. The rotary pressure filter of claim 4, wherein the component of the rotary pressure filter comprises the filter drum.

18. The rotary pressure filter of claim 9, wherein the second hollow element is arranged in a direction parallel to the axis of rotation of the filter drum with respect to all control head separating elements.

19. The rotary pressure filter of claim 13, wherein the seal extending at least partially around the frame comprises an elastomer material.

20. A rotary pressure filter suitable for use in treatment of medical products or foodstuffs, the rotary pressure filter comprising: a filter drum that can be rotated about an axis of rotation; a plurality of filter cells arranged along an outer circumference of the filter drum; a housing surrounding the filter drum, wherein a process space is formed between the filter drum and the housing; and at least one separating element dividing the process space into a plurality of treatment zones, wherein at least one treatment zone is associated with a housing connector via which one or more of a fluid or a suspension can be introduced into the respective treatment zone, wherein the treatment zones are separated from one another such that the one or more of the fluid or the suspension is substantially prevented from passing from a first treatment zone into a second treatment zone, wherein the second treatment zone is adjacent the first treatment zone according to a rotation of the filter drum, wherein the at least one separating element is configured to prevent a permanent accumulation of fluid in a region of the separating element, wherein the filter drum is sealed relative to the housing such that the one or more of the fluid or the suspension from at least one treatment zone is substantially prevented from exiting the at least one treatment zone other than through filter cells located in the treatment zone, and such that a permanent accumulation of the one or more of fluid or suspension in a region of a transition between filter drum and the housing is prevented, and wherein a resilient hollow element which can be filled with a second fluid is arranged adjacent to at least one of the separating elements in a direction parallel to the axis of rotation of the filter drum, wherein the hollow element is designed to close a gap between said hollow element and the separating element by filling the hollow element.

Description

[0034] Hereinafter, the present invention will be described in greater detail using an embodiment with reference to the accompanying drawings, in which:

[0035] FIG. 1 shows a detail of a side cross-section of a rotary pressure filter according to the invention in the region of a housing of the rotary pressure filter;

[0036] FIG. 2 shows a further detail of a side cross-section of the rotary pressure filter according to the invention in the region of the housing of the rotary pressure filter;

[0037] FIG. 3 shows a further detail of a side cross-section of the rotary pressure filter according to the invention in the region of the housing of the rotary pressure filter;

[0038] FIG. 4 shows a detail of a side cross-section of the rotary pressure filter according to the invention in the region of a control head of the rotary pressure filter;

[0039] FIG. 5 shows a side cross-section of a filter cell of the rotary pressure filter according to the invention; and

[0040] FIG. 6 shows a side cross-sectional view of the rotary pressure filter according to the invention without a filter drum.

[0041] In FIG. 1, a rotary pressure filter according to the invention is generally denoted with reference sign 10. The rotary pressure filter 10 comprises a housing 12 and a filter drum 14 arranged therein which rotates about an axis of rotation A. A process space 16 into which suspension to be filtered can be introduced via a housing connector 18 is arranged between the housing 12 and the filter drum 14. The suspension is divided into liquid and solid components in a filter cell 20 of the filter drum 14, with the liquid components of the suspension leaving the filter cell 20 radially inwards in relation to the filter drum 14 and solid components being retained in the filter cell 20. In a treatment zone downstream of the introduction of suspension into the process space 16, the components of the suspension remaining in a particular filter cell 20 can also be treated with treatment fluids, such as washing liquids or drying air, and then discharged.

[0042] In order to prevent suspension and/or treatment fluid from accumulating permanently, i.e. in such a way that it cannot be reliably removed by cleaning the filter cell, for example at the end of a treatment cycle or at the latest during cleaning before changing to a different product to be treated, a seal 24 is associated with the process space 16 or a gap 22 by which the process space 16 is reduced at its axial end, in a direction axial to the axis of rotation A. In the embodiment shown in FIG. 1, the seal 24 comprises a hollow element 26 which can be filled with fluid via a fluid line (not shown) in order to be inflated, i.e. to increase in volume, or from which fluid can be discharged from the hollow element 26 via the fluid line can so that the hollow element 26 decreases in volume.

[0043] Adjacent to the hollow element 26 and inserted between the hollow element 26 and the process space 16 is a sealing strip 28 disposed which is suitable for sealing the process space 16 from an outer side in such a way that no product or treatment fluid can escape from the process space 16 at this point.

[0044] Since the hollow element 26 is fastened to the housing 12 in the embodiment shown in FIG. 1, a sliding element 30 which is in sliding contact with the filter drum 14 is also arranged between the hollow element 26 and the filter drum 14. The sliding element 30 is also attached to the housing 12.

[0045] FIG. 2 shows, in a side cross-sectional view, how the housing connector 18 is connected to the housing 12 in the embodiment shown without any sharp transitions or undercuts occurring. In the example shown, the housing connector 18 is integrally bonded to the housing 12, for example by a welding process. A transition 32 between the housing 12 and the housing connector 18 therefore has a smooth course, forming a radius from a side of the housing 12 facing the process space 16 to an inside of the housing connector 18.

[0046] FIG. 3 shows the rotary pressure filter 10 according to the invention in a sectional view, the sectional plane of which extends through a separating element 34 which separates two treatment zones which are adjacent in the direction of rotation of the filter drum 14 in a gas-tight manner. Analogously to the seal 24 of the process space 16 described with reference to FIG. 1, i.e. between the housing 12 and the filter drum 14, there is also a seal 36 and 38 at each of the two longitudinal ends, in relation to the axis of rotation A of the filter drum 14, of the separating element 34, each of which comprises a hollow element 26′, a sealing strip 28′ and a sliding element 30′. On the one hand, the seals 36 and 38 prevent foreign matter from migrating axially outwards along a contact surface between the separating element 34 and the filter drum 14 and, on the other hand, prevent foreign matter from passing out of the filter cell 20 into a pressure chamber 40 which is arranged in a radial direction outside the separating element 34 and via which contact pressure from the separating element 34 can be exerted on the filter drum 14.

[0047] In a particular embodiment, the seal 24 and the seal 36 can be formed from the same components, i.e. from the hollow element 26, the sealing strip 28 and the sliding element 30. The same naturally applies to a seal 38, although an associated seal opposite the seal 24 is not shown in FIG. 1.

[0048] Liquid components of the suspension as well as treatment fluids which have passed radially inwards through the filter cell 20 on the filter drum 18 are guided out of the rotary pressure filter 10 via a control head 42. It can be advantageous to divide the control head 42 into discharge zones, at least partially analogously to the division of the process space 16 into treatment zones. The discharge zones are separated by control head separating elements 44.

[0049] In the embodiment shown, in contrast with the separating elements 34, the control head separating elements 44 are rigidly connected to the filter drum 14 so that they rotate with it about the control head 42. It can be seen in FIG. 4 that, above the control head separating elements 44, i.e. radially inwards in relation to the axis of rotation A, a control head pressure chamber 46 is arranged which, analogously to the pressure chamber 40, can be filled with fluid in such a way that the control head separating elements 44 can be subjected to a corresponding contact pressure on the control head 42. In order to be able to prevent foreign matter from accumulating at the ends of a particular control head separating element 44 that are axial in relation to the axis of rotation A, hollow elements 48 and 50 which can close a relevant gap 52 and 54 are provided on these longitudinal ends of the control head separating element 44. Fluid lines 56 and 58 via which the hollow elements 48 and 50 can be filled and drained can also be seen in FIG. 4. In the embodiment shown, the fluid lines 56 and 58 are designed as centrally drilled threaded bolts.

[0050] FIG. 5 shows a detail of the rotary pressure filter 10 according to the invention, which shows a filter cell 20 of the filter drum 14. A filter unit 60 is arranged in the filter cell 20 and comprises a frame 62 and a filter cloth 64 arranged on the frame 62 of the filter unit 60. The filter cloth 64 is flush with a surrounding edge of the frame 62 of the filter unit 60 and forms a curved surface therewith in the circumferential direction of the filter drum 14.

[0051] A drain line 66 is provided in an interior of the frame 62, via which drain line liquid components of the suspension and treatment fluids that have passed through the filter cloth 64 can leave the filter cell 20 in direction of the control head 42. A seal 68 in the form of a sealing cord is arranged circumferentially around the frame 62 of the filter cell 60. In FIG. 5, the seal 68 is shown uncompressed. In reality, however, the seal 68 would be deformed by a chamfer 70, formed on a filter cell base 72 of the filter cell 20, and a contact surface 74 of the frame 62 of the filter unit 60 such that the seal 68 also substantially reaches the level of the curved surface of the filter cloth 64 and the surrounding edge of the frame 62.

[0052] The drain line 66 can advantageously be surrounded by a further seal 76 between filter cell base 72 and frame 62.

[0053] In the embodiment shown, a supporting fabric 78 is arranged under the filter cloth 64 and is used to provide the filter cloth 64 with a large contact surface or to prevent the filter cloth 64 from sagging into the frame 62 of the filter cell 60. The supporting fabric 78 is sunk into the frame 62 so that the filter cloth 64 can extend as far as an outer edge of the frame 62 without a step between the frame 62 and the supporting fabric 78 interfering with the course of the filter cloth 64.

[0054] FIG. 6 shows a side cross-sectional view of a rotary pressure filter 10 according to the invention. The filter drum 14 is not shown in FIG. 6. It can be seen here that the housing 12 of the rotary pressure filter 10 is connected to a stuffing box gland 80 which presses a stuffing box packing 82 against the housing 12 in such a way that the stuffing box packing 82 is deformed radially inwards in order to form a seal with respect to the filter drum 14. The stuffing box gland 80 is connected to the housing 12 via threaded bolts 84.

[0055] A nut 86 via which a second containment 88 is fastened to the housing 12 of the rotary pressure filter 10 is connected at an end of a relevant threaded bolt 84 that is opposite the housing 12. The second containment 88 comprises a radial shaft sealing ring 90 which comes into contact with the filter drum 14. In this way, in addition to the stuffing box packing 82, a further seal with respect to an outer side of the rotary pressure filter 10 is provided.