PRESSURE TWIST FILTER

Description

[0001] The present invention relates to a pressure rotary filter which is suitable for use in the treatment of medical products and / or foodstuffs, wherein the pressure rotary filter comprises: a filter drum which is rotatable about a rotation axis, a plurality of filter cells which are arranged along an outer circumference of the filter drum, a housing which surrounds the filter drum, wherein a process space is formed between the filter drum and the housing, and at least one separating element which divides the process space into a plurality of treatment zones, wherein at least one treatment zone is assigned a fluid inlet via which fluid can be introduced into the respective treatment zone.

[0002] The applicant has been marketing pressure filters for many years. In such rotary pressure filters, a suspension, which is a mixture of liquid and solids, is applied to a rotating filter drum. The filter drum is designed in such a way that liquid in the suspension can pass through one wall of the filter drum, whereas solids in the suspension remain on one surface of the filter drum. Consequently, a layer of solids forms on the surface of the filter drum, which is referred to in technical circles as a "filter cake."

[0003] As the filter drum rotates, the suspension or filter cake passes through various treatment zones, such as washing and drying zones, which are separated from each other by gas-tight separation elements. Solids and / or treatment fluid retained by the filter may accumulate in undercuts and narrow gaps, particularly in the area of ​​seals that seal the process chamber.

[0004] In order to process food products or pharmaceutical products, for example, with a pressure rotary filter, it is imperative that the product to be processed is not contaminated by residues from previously processed products.

[0005] Examples of pressure rotary filters of a general type are known from WO 02 / 100512 A1, DE 196 54 165 C1 and DE 12 04 628 B, whereby WO 2009 / 135987 A2 should also be mentioned for the sake of completeness.

[0006] It is therefore the object of the present invention to provide a pressure rotary filter by which an unwanted accumulation of solids and / or treatment fluid can be greatly reduced or even completely avoided.

[0007] This object is achieved according to the invention by a rotary pressure filter which is suitable for use in the treatment of medical devices and / or foodstuffs, the rotary pressure filter comprising: a filter drum rotatable about a rotation axis, a plurality of filter cells arranged along an outer circumference of the filter drum, a housing surrounding the filter drum, a process chamber being formed between the filter drum and the housing, and at least one separating element dividing the process chamber into a plurality of treatment zones, at least one treatment zone being assigned a housing nozzle through which fluid and / or suspension can be introduced into the respective treatment zone, the treatment zones being separated from one another in such a way that fluid / suspension is substantially prevented from entering a treatment zone adjacent to the rotation of the filter drum, the at least one separating element being designed to prevent permanent accumulation of fluid in the region of the separating element,wherein the filter drum is sealed from the housing in such a way that fluid / suspension of at least one treatment zone is substantially prevented from escaping from the corresponding treatment zone other than through filter cells located in the treatment zone, and that permanent accumulation of fluid / suspension in the region of a transition between the filter drum and the housing is prevented, wherein adjacent to at least one of the separating elements, in particular to all separating elements, in a direction parallel to the axis of rotation of the filter drum, in particular on both sides, an elastic hollow element which can be filled with a fluid is arranged, which is designed to close a gap between the respective hollow element and the separating element by filling the hollow element.

[0008] The expression "that fluid / suspension of at least one treatment zone is substantially prevented from escaping from the corresponding treatment zone other than through filter cells located in the treatment zone" is intended to refer in particular to those treatment zones in which the filter cake is formed or treated. In addition, there can also be treatment zones in which treatment fluid is introduced into the treatment zone from radially outside and leaves it again radially outwards, for example drying air in drying zones. Furthermore, a cleaning zone can be provided in which a treatment fluid is passed from radially inside through the filter cell to radially outwards, for example in order to clean the filter cloth. In general, the above-mentioned expression is intended to include that fluid orSuspension is to be prevented from escaping from a treatment zone at locations that were not intended for the discharge of fluid / suspension. This usually applies to the discharge of fluid / suspension from a treatment zone in the direction of rotation of the filter drum and / or in the axial direction of the rotation axis of the filter drum.

[0009] The hollow elements can, for example, be designed to be filled with a gas, for example air, from a source connected to them.

[0010] By filling the hollow elements, a gap axially adjacent to the process chamber and / or a separating element can be closed in such a way that the accumulation of solids or treatment fluid is prevented. This also prevents foreign matter from entering the pressure chamber in separating elements that have a pressure chamber arranged on a radially outer side of the filter drum, via which the separating elements can be displaced toward the filter drum.

[0011] The flexible design of the hollow element allows it to engage virtually any counter surface, reliably closing a gap that needs to be closed. Additionally, a control unit can be connected to at least one hollow element, which is configured to detect a pressure drop in the hollow element and automatically initiate a corresponding supply of fluid into the hollow element.

[0012] The term "accumulation" or "deposit" here means in particular that solids and / or treatment fluid which have entered a corresponding gap cannot be removed in a self-cleaning manner in the sense of an exchange.

[0013] In order to achieve this self-cleaning effect in those gaps which cannot be avoided by design, such gaps, in particular with a gap size of 0.5 mm or more, and associated radii, in particular with a radius of 5 mm or more, can be formed in the pressure rotary filter according to the invention.

[0014] Advantageously, a sealing strip can be assigned to a hollow element and arranged adjacent to the gap to be closed, whereby the sealing strip can advantageously comprise a PTFE material. By using a sealing strip, the function of conforming to a counter surface and thus sealing the gap can be taken over by the sealing strip, so that the hollow element can primarily serve the function of applying force. This also allows the hollow element to have very thin walls.

[0015] It has been shown that a PTFE sealing tape can have both good sealing properties and, in the case of a seal against a relatively moving element, for example the rotation of the filter drum relative to the housing, good sliding properties.

[0016] To ensure cleaning of all surfaces inside the housing, a cleaning bar can be provided on the filter drum, which rotates together with the drum and along which several nozzles, for example flat jet nozzles, are arranged. This cleaning bar can be specially designed to clean the housing interior of the rotary pressure filter. To clean the filter drum and filter cells or filter units arranged therein, at least one further cleaning bar with a row of nozzles can be arranged in at least one corresponding treatment zone of the housing. This cleaning bar(s) is / are, in particular, stationary relative to the filter housing. In the case of several cleaning bars, the number of nozzles in a second row can be increased compared to a first row in order to reach every point on the filter drum with sufficient cleaning performance.Furthermore, drainage holes can be arranged in treatment zones through which the supplied cleaning fluid can be drained. The drainage holes can be opened only for one washing process, for example, between the treatment of two different products, and can be closed, in particular automatically, for one product treatment process.

[0017] Advantageously, the nozzles, at least of the cleaning bar rotating with the filter drum, and in particular of all cleaning bars, can be designed flush with the outer periphery of a component in which the nozzles are arranged. Both with nozzles protruding from the component and with nozzles recessed into the component, there is a risk of product accumulating in edges and undercuts. A flush design can prevent product accumulation.

[0018] A hollow element can also be associated with a sliding element, which is arranged between the hollow element, adjacent to it, and a component of the rotary pressure filter, in particular the filter drum, that is displaceable relative to it. This sliding element can, in particular, be an element separate from the sealing band, which can be arranged on a different side of the hollow element than the sealing band.

[0019] The sliding element can be fixed to the same component to which the hollow element is also fixed. For example, if the hollow element is connected to the housing, through which a fluid line connected to the hollow element runs, the sliding element can also be connected to the housing, thus preventing relative displacement between the sliding element and the hollow element.

[0020] Advantageously, at least one of the hollow element, the sealing band, and the sliding element can be annular. For example, a sealing band, a hollow element, and a sliding element can be arranged at each longitudinal end of the filter drum, the annular configuration of which extends in the circumferential direction of the filter drum. In particular, a plurality of fluid lines can be assigned to an annular hollow element, via which fluid can be directed into or out of the hollow element to inflate or deflate it.

[0021] At least one of the hollow element, the sealing band and the sliding element can be arranged substantially concentrically to the axis of rotation of the filter drum.

[0022] In particular, the components that form the seal of the filter drum with respect to the housing can simultaneously be the components that form the seal of the separating elements with respect to the housing. It is thus conceivable for an annular hollow element, for example in combination with an annular sealing band and an annular sliding element, to provide a seal of a separating element with respect to the housing at a first section and a seal of the filter drum with respect to the housing at a second section. A single hollow element, optionally in combination with a sealing band and / or a sliding element, can also form all seals of the separating elements of the rotary pressure filter with respect to the housing on the same side.

[0023] The pressure rotary filter can further comprise a control head which is arranged radially inward relative to the filter drum and via which fluid which has passed through the filter cells in a respective treatment zone leaves the pressure rotary filter, wherein the control head is divided by control head separating elements into a plurality of discharge zones which are adjacent to the filter drum and the control head in such a way that the discharge zones are fluidically sealed from one another, wherein a hollow element which can be filled with a fluid is arranged on one control head separating element, in particular on both sides, in a direction parallel to the axis of rotation of the filter drum, which hollow element is designed to close a gap between the respective hollow element and the control head separating element by filling the hollow element.

[0024] It should be noted at this point that the above-mentioned features, advantages, and properties described with reference to the above-mentioned hollow elements also apply to the hollow element associated with a control head separator. Thus, by using a corresponding hollow element, a control head separator can be sealed, particularly axially, with respect to the rotational axis of the filter drum.

[0025] Here too, a sealing strip and / or sliding element can be assigned to the hollow element(s) adjacent to a control head separating element and arranged adjacent to the hollow element at the gap to be closed, wherein in this regard, reference is again made to the sealing strip / sliding element described above.

[0026] In a further development of the present invention, a filter unit can be arranged in a filter cell, in particular each filter cell, which filter unit carries a filter cloth which is designed to retain solids from a suspension to be filtered which reaches the filter cloth, from a size defined by the filter cloth and to allow fluids to pass through, wherein the filter cloth and a frame of the filter unit are produced as separate components and are connected to one another using a joining process, in particular a thermal joining process, such as one of a welding process and an ultrasonic welding process, or wherein the filter cloth and the frame are produced together in one piece, in particular using a 3D printing process.By directly connecting the filter cloth to the frame of the filter unit, a cord, as used in conventional filter units to attach the filter cloth to the frame, can be dispensed with. This, in turn, prevents gaps created by the use of the cord, in which product can accumulate. In particular, the filter cloth can be connected to the frame in such a way that one side of the filter cloth, on which a filter cake builds up, is essentially flush with an adjacent surface of the frame of the filter unit. A corresponding weld seam can thus extend essentially in a plane or a surface curved around a spatial axis.

[0027] An ultrasonic welding process can be used particularly when using plastic materials for the filter unit, i.e. the frame and / or the filter cloth, such as PP / PVDF.

[0028] Furthermore, a so-called "second containment" can be provided on the bearing plates and on a control head of the rotary pressure filter. This can be used to further prevent the possible leakage of hazardous substances for occupational safety reasons by creating an additional seal against the outside of said components. This second containment can be arranged, in particular, outside, preferably coaxially with, a stuffing box gland of the filter drum. The second containment can be connected to the housing via the same fastening elements, for example, threaded bolts, with which the stuffing box gland of the filter drum is attached to the housing. The second containment advantageously has at least one radial shaft seal ring, which is designed to come into contact with the filter drum to provide an additional seal.

[0029] Advantageously, the filter unit can have a seal which runs at least partially around the frame of the filter cell and is designed to seal a gap between a filter cell and a filter unit arranged therein, wherein the seal can in particular comprise an elastomer material. The seal, which can for example be designed as a sealing cord with a round profile, can be deformed in the assembled state of the filter unit in a respective filter cell to such an extent that the seal completely closes a gap between the filter unit and the filter cell, i.e. the seal, which is arranged circumferentially on the frame of the filter unit, is deformed in such a way that it lies essentially at the same height as an associated filter cloth in a direction radial to the axis of rotation of the filter drum. In this way, the gap and / or undercuts between the filter unit and the filter cell orThe filter cell wall must be closed in such a way that any product, particularly solids, that has accumulated there can be reliably removed when the filter cell is cleaned.

[0030] In order to cause the seal of the filter unit to deform, the filter unit can be screwed to the filter drum, in particular using stud bolts which engage into the filter unit from a radially inner side of the filter drum by transforming the filter drum. Furthermore, a chamfer can be formed on a filter cell base against which the seal of the filter unit rests, which chamfer promotes deformation of the seal radially outwards with respect to the filter drum. In order to be able to reduce a space in the filter cell above the filter cloth, i.e. a space in which a filter cake builds up, cell supports can be arranged between the filter unit and the filter cell base. In this case, the cell supports can have a chamfer in a manner analogous to the filter cell base to assist the deformation of the seal.

[0031] A further seal may be arranged between the filter unit and the filter cell base in a manner surrounding a fluid drain line through the filter unit so that no fluid from the drain line can enter a gap between the filter unit and the filter cell base.

[0032] In particular, the filter unit can be designed to be removable from the filter cell. This allows for easily replacing defective filter units, for example, those with a damaged filter cloth.

[0033] Furthermore, the housing nozzles, through which suspension and / or fluid can be introduced into or discharged from the process chamber, can be welded to the housing. This prevents intersections where deposits can form.

[0034] In general, it can be advantageous for a hygienic design of the pressure rotary filter according to the invention if all surfaces that can come into contact with suspension / treatment fluid have radii of at least 5 mm and a surface roughness of maximum Rz4 (µm).

[0035] In the following, the present invention will be described in more detail by way of example with reference to the accompanying drawings, in which: Figure 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; Figure 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; Figure 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; Figure 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; Figure 5 shows a side cross-section of a filter cell of the rotary pressure filter according to the invention; and Figure 6 shows a side cross-sectional view of the rotary pressure filter according to the invention without a filter drum.

[0036] In Figure 1A rotary pressure filter according to the invention is generally designated by the reference numeral 10. The rotary pressure filter 10 comprises a housing 12 and a filter drum 14 arranged therein, which rotates about a rotation axis A. A process chamber 16 is arranged between the housing 12 and the filter drum 14, into which process chamber the suspension to be filtered can be introduced via a housing connection 18. 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 inward with respect 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 chamber 16, the portions of the suspension remaining in a respective filter cell 20 can be further treated with treatment fluids, such as washing liquids or drying air, and then discharged.

[0037] 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 assigned to the process chamber 16 or a gap 22, to which the process chamber 16 reduces at its axial end, in a direction axial to the rotation axis A. The seal 24 comprises in the Figure 1illustrated embodiment, a hollow element 26 which can be filled with fluid via a fluid line (not shown) in order to inflate, i.e. to increase in volume, or from which fluid can be discharged from the hollow element 26 via the fluid line so that the hollow element 26 decreases in volume.

[0038] Adjacent to the hollow element 26 and inserted between the hollow element 26 and the process chamber 16, a sealing band 28 is arranged, which is suitable for sealing the process chamber 16 from an outside in such a way that no product or treatment fluid can escape from the process chamber 16 at this point.

[0039] Since the hollow element 26 in the Figure 1In the embodiment shown, the hollow element 26 is attached to the housing 12, a sliding element 30 is also arranged between the hollow element 26 and the filter drum 14, which is slidably connected to the filter drum 14. The sliding element 30 is also attached to the housing 12.

[0040] Figure 2 shows, in a side cross-sectional view, how the housing nozzle 18 is connected to the housing 12 of the illustrated embodiment, without any sharp transitions or undercuts. In the example shown, the housing nozzle 18 is integrally connected to the housing 12, for example, by a welding process. A transition 32 between the housing 12 and the housing nozzle 18 therefore has a smooth profile, forming a radius from a side of the housing 12 facing the process chamber 16 to an inner side of the housing nozzle 18.

[0041] In Figure 3The rotary pressure filter 10 according to the invention is shown in a sectional view, the sectional plane of which runs through a separating element 34, which separates two treatment zones adjacent to each other in the direction of rotation of the filter drum 14 in a gas-tight manner. Analogous to the view shown with reference to Figure 1In addition to the described seal 24 of the process chamber 16, that is, between the housing 12 and the filter drum 14, a respective seal 36 and 38 is also arranged at the two longitudinal ends, with respect to the rotation axis 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'. The seals 36 and 38 prevent, on the one hand, foreign matter from migrating axially outward along a contact surface between the separating element 34 and the filter drum 14, and, on the other hand, prevent foreign matter from the filter cell 20 from entering a pressure chamber 40, which is arranged in a radial direction outside the separating element 34 and via which a contact force of the separating element 34 can be exerted on the filter drum 14.

[0042] In a particular embodiment, the seal 24 and the seal 36 can be formed from one and the same components, that is, from the hollow element 26, the sealing strip 28 and the sliding element 30. The same applies, of course, to a seal 38, wherein an associated seal opposite the seal 24 in Figure 1 is not shown.

[0043] Liquid portions of the suspension as well as treatment fluids that have passed radially inward through the filter cell 20 on the filter drum 18 are discharged from the rotary pressure filter 10 via a control head 42. It may be advantageous to divide the control head 42 into discharge zones, at least partially analogous to the division of the process chamber 16 into treatment zones. The discharge zones are separated from one another by control head separating elements 44.

[0044] In the illustrated embodiment, in contrast to the separating elements 34, the control head separating elements 44 are firmly connected to the filter drum 14, so that they rotate together with the latter around the control head 42. Figure 4 It can be seen that above the control head separating elements 44, i.e., radially inward with respect to the rotation axis A, a control head pressure chamber 46 is arranged, which can be filled with fluid analogously to the pressure chamber 40 such that the control head separating elements 44 can be subjected to a corresponding contact pressure on the control head 42. In order to prevent the accumulation of foreign matter at the axial ends of a respective control head separating element 44 with respect to the rotation axis A, hollow elements 48 and 50 are provided at these longitudinal ends of the control head separating element 44, which can close a respective gap 52 and 54. In Figure 4Also visible are fluid lines 56 and 58, through which the hollow elements 48 and 50 can be filled and drained. In the illustrated embodiment, the fluid lines 56 and 58 are designed as centrally drilled threaded bolts.

[0045] In Figure 5 A section of the rotary pressure filter 10 according to the invention is shown, showing a filter cell 20 of the filter drum 14. A filter unit 60 is arranged in the filter cell 20, which 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, together with the frame, forms a curved surface extending in the circumferential direction of the filter drum 14.

[0046] A drain line 66 is provided inside the frame 62, through which liquid portions of the suspension and treatment fluids that have passed through the filter cloth 64 can leave the filter cell 20 in the 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. Figure 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 essentially reaches the height of the curved surface of the filter cloth 64 and the surrounding edge of the frame 62.

[0047] Advantageously, the drain line 66 can be surrounded by a further seal 76 between the filter cell base 72 and the frame 62.

[0048] In the illustrated embodiment, a support fabric 78 is arranged beneath the filter cloth 64. This support fabric serves to provide the filter cloth 64 with a large contact surface and to prevent the filter cloth 64 from sagging into the frame 62 of the filter cell 60. The support fabric 78 is recessed into the frame 62 so that the filter cloth 64 can extend to an outer edge of the frame 62 without a step between the frame 62 and the support fabric 78 that would disrupt the flow of the filter cloth 64.

[0049] In Figure 6 is a side cross-sectional view of a rotary pressure filter 10 according to the invention. The filter drum 14 is in Figure 6Not shown. It can be seen that a fabric gland 80 is connected to the housing 12 of the rotary pressure filter 10, which presses a fabric gland packing 82 against the housing 12 in such a way that the fabric gland packing 82 is deformed radially inward to form a seal against the filter drum 14. The fabric gland 80 is connected to the housing 12 via threaded bolts 84.

[0050] At an end of each threaded bolt 84 opposite the housing 12, a nut 86 is connected to the bolt, via which a second containment 88 is fastened to the housing 12 of the rotary pressure filter 10. The second containment 88 comprises a radial shaft seal 90, which comes into contact with the filter drum 14. In this way, in addition to the stuffing box packing 82, a further seal is provided against an outside of the rotary pressure filter 10.

Claims

1. Rotary pressure filter (10) suitable for use in the treatment of medical products and / or foodstuffs, wherein the rotary pressure filter (10) comprises: a filter drum (14) which is rotatable about an axis of rotation (A), a plurality of filter cells (20) which are arranged on the filter drum (14) along an outer circumference thereof, a housing (12) which surrounds the filter drum (14), wherein a process space (16) is formed between the filter drum (14) and the housing (12), and at least one separating element (34) which divides the process space (16) into a plurality of treatment zones, wherein there is associated with at least one treatment zone a housing connector (18) via which fluid and / or suspension can be introduced into the respective treatment zone, wherein the treatment zones are separated from one another in such a manner that fluid / suspension is substantially prevented from passing from one treatment zone into an adjacent, according to a rotation of the filter drum (14), treatment zone, wherein the at least one separating element (34) is designed to prevent a permanent accumulation of fluid in the region of the separating element (34), wherein the filter drum (14) is sealed with respect to the housing (12) in such a manner that fluid / suspension of at least one treatment zone is substantially prevented from leaving the corresponding treatment zone other than through filter cells (20) located in the treatment zone, and that a permanent accumulation of fluid / suspension in the region of a transition between the filter drum (14) and the housing (12) is prevented, characterised in that a resilient hollow element (26') which can be filled with a fluid is arranged adjacent to at least one of the separating elements (34), in particular adjacent to all the separating elements (34), in a direction parallel to the axis of rotation (A) of the filter drum (14), in particular on both sides, which hollow element is adapted, by filling of the hollow element (26'), to close a gap between the respective hollow element (26') and the separating element (34).

2. Rotary pressure filter (10) according to claim 1, characterised in that a sealing strip (28, 28') is associated with a hollow element (26, 26') and is arranged adjacent thereto at the gap that is to be closed, wherein the sealing strip (28, 28') advantageously comprises a PTFE material.

3. Rotary pressure filter (10) according to claim 1 or 2, characterised in that there is provided at the filter drum a cleaning bar which rotates together with the filter drum and along which there are arranged a plurality of nozzles, for example flat jet nozzles.

4. Rotary pressure filter (10) according to any one of claims 1 to 3, characterised in that there is associated with a hollow element (26, 26') a sliding element (30, 30') which is arranged between the hollow element (26, 26'), adjacent thereto, and a component of the rotary pressure filter (10) that is displaceable relative thereto, in particular the filter drum (14).

5. Rotary pressure filter (10) according to claim 4, characterised in that the sliding element (30, 30') is fixed to the same component to which the hollow element (26, 26') is also fixed.

6. Rotary pressure filter (10) according to any one of claims 1 to 5, optionally according to claim 2 and / or claim 4, characterised in that at least one of the hollow element (26, 26'), the sealing strip (28, 28') and the sliding element (30, 30') is annular.

7. Rotary pressure filter (10) according to claim 6, optionally according to claim 2 and / or claim 4, characterised in that at least one of the hollow element (26, 26'), the sealing strip (28, 28') and the sliding element (30, 30') is arranged substantially concentrically to the axis of rotation (A) of the filter drum (14).

8. Rotary pressure filter (10) according to any one of claims 1 to 7, characterised in that the components that form the seal (24) between the filter drum (14) and the housing (12) are at the same time the components that form the seal (36) between the separating elements (34) and the housing (12).

9. Rotary pressure filter (10) according to any one of claims 1 to 8, characterised in that the rotary pressure filter (10) further comprises a control head (42) which is arranged radially inwards relative to the filter drum (14) and via which fluid that has entered a respective treatment zone through the filter cells (20) leaves the rotary pressure filter (10), wherein the control head (42) is divided by control head separating elements (44) into a plurality of discharge zones which adjoin the filter drum (14) and the control head (42) in such a manner that the discharge zones are fluidically sealed with respect to one another, wherein a hollow element (48, 50) which can be filled with a fluid is arranged adjacent to a control head separating element (44), in particular adjacent to all the control head separating elements (44), in a direction parallel to the axis of rotation (A) of the filter drum (14), in particular on both sides, which hollow element is adapted, by filling of the hollow element (48, 50), to close a gap (52, 54) between the respective hollow element (48, 50) and the control head separating element (44).

10. Rotary pressure filter (10) according to claim 9, characterised in that a sealing strip is associated with the hollow element(s) (48, 50) adjacent to a control head separating element (44) and is arranged adjacent to the hollow element (48, 50) at the gap (52, 54) that is to be closed.

11. Rotary pressure filter (10) according to any one of claims 1 to 10, characterised in that a filter unit (60) is arranged in a filter cell (20), in particular in each filter cell (20), which filter unit carries a filter cloth (64) which is adapted to retain, from a suspension to be filtered that reaches the filter cloth (64), solids above a size defined by the filter cloth (64) and to allow fluids to pass through, wherein the filter cloth (64) and a frame (62) of the filter unit (60) are produced as separate components and connected together using a joining process, in particular a thermal joining process, such as, for example, one of a welding process and an ultrasonic welding process, or wherein the filter cloth (64) and the frame (62) are produced together in one piece, in particular using a 3D printing process.

12. Rotary pressure filter (10) according to any one of claims 1 to 11, characterised in that a second containment (88) is further provided for bearing shields and at the control head (42) of the rotary pressure filter (10).

13. Rotary pressure filter (10) according to claim 11 or 12, characterised in that the filter unit (60) has a seal (68) extending at least partially around the frame (62) of the filter cell (20), which seal is adapted to seal a gap between a filter cell (20) and a filter unit (60) arranged therein, wherein the seal (68) comprises in particular an elastomer material.

14. Rotary pressure filter (10) according to any one of claims 11 to 13, characterised in that the filter unit (60) is configured so as to be removable from the filter cell (20).

15. Rotary pressure filter (10) according to any one of claims 1 to 14, characterised in that housing connectors (18) which are connected to the housing (12) and via which suspension and / or fluid can be introduced into or discharged from the process space (16) are welded to the housing (12).