Flexible end caps for ceramic flat plate filters

Abstract

The present invention relates to a method for radially sealing a ceramic plate filter (1) using a flexible end cap (10), a set (9) consisting of a ceramic plate filter (1), a flexible end cap (10), and an adhesive (16) used therein, and the flexible end cap itself. In particular, the flat plate filter (1) has two axial end faces (4) and radial side faces (2), and inside it, a filtrate channel extends along the surface of the flat plate filter and opens at at least one axial end face (4) of the flat plate filter (1). The end cap (10) is configured to be attached to the end face end region of the flat plate filter (1) and is configured to be permanently attached to the flat plate filter (1) by adhesive and has at least one filtrate outlet (11) and a filtrate collection channel (12). In the attached state, the filtrate supplied from the filtrate channel (3) of the flat plate filter (1) is collected in the filtrate collection channel (12) and sent to at least one filtrate outlet (11). The end cap (10) is made of an elastic material and has a groove-shaped recess (14). In the expanded state, the recess (14) is capable of receiving the insertion area (5) of the flat plate filter (1), and in the non-expanded state, the recess (14) has an effective space that is the same size as or smaller than the insertion area (5) of the flat plate filter (1).

Description

Technical Field

[0001] The present invention relates to a method for radially sealing a ceramic flat filter using a flexible end cap, a ceramic flat filter, a flexible end cap, and a set of adhesives used for this purpose, as well as the flexible end cap itself.

Background Art

[0002] Ceramic flat filters have become popular as so-called microfilters in water treatment and wastewater treatment over the past 20 years. Generally, microfilters are used after the post-clarification tank in sewage treatment plants for the purpose of reliably separating microorganisms and other organic substances. The microfilter in this specification refers to a filter having a pore size small enough to retain microorganisms during the filtration process. Such microfilters are often called microfilters, ultrafilters, nanofilters, etc. depending on the pore size.

[0003] Ceramic flat filters are manufactured from various porous ceramic materials by various manufacturers around the world. Generally, the ceramic flat filter 1 has a plate-like basic shape as shown in Fig. 1A (perspective view) and Fig. 1B (front view). The flat filter 1 has an outer surface 2 (liquid supply side) formed on the radial side and with rounded edges, against which the liquid to be filtered impinges. A plurality of filtrate channels 3 extend inside the flat filter 1 and open at (at least) one axial end face 4 of the flat filter 1. In this specification, the surface of the filtrate channel 3 is also referred to as the inner surface of the filter. The liquid to be filtered contacts the outer radial side surface 2, enters the filter interior through the pores of the ceramic, reaches the filtrate channels 3 provided therein, and is discharged from the end face to the outside of the flat filter 1 through these channels. Generally, the longitudinal length of the ceramic flat filter is about 150 to 1000 mm. Generally, the width of the axial end face of the ceramic flat filter is 80 to 300 mm, and its thickness is 3 to 8 mm.

[0004] The solids removed by filtration accumulate as filtration residue on the outer surface of the flat plate filter. When the deposit reaches a certain thickness, it is generally removed by a process known as backwashing. In this process, a clean liquid is injected into the filtrate channels and pushed out through the ceramic of the filter. The deposit on the outer surface is stirred up by the liquid, ensuring that the radial sides of the filter are thoroughly cleaned.

[0005] To prevent the liquid being filtered from mixing with the filtrate, the outer surface (liquid feed side) of the plate filter must be sealed from the inner surface so that filtration can proceed from the outside through the inside to the filtrate channel. If the filtrate channel is open at both ends of the plate (which is often the case with ceramic plate filters as they are manufactured by extrusion), then such sealing is required at both ends of the plate filter.

[0006] Previously, this end-face sealing has been achieved using two main approaches in conventional technology. In the first approach, shown in Figure 2, the insertion area 5 on the end face side of the ceramic plate filter 1 is inserted into the recess 6 of the dimensionally stable end cap 7, and then bonded to the end cap 7 with potting adhesive 8. The insertion depth of the filter into the end cap is typically 5 to 15 mm. The end cap is usually made of hard plastics such as PES, PVC, and ABS, glass fiber reinforced plastic materials, ceramic, or metal.

[0007] In addition to their sealing function, end caps often also serve to collect filtrate from the filtrate channels of a flat plate filter and discharge it through an outlet to a larger collection container (e.g., a pipe, hose, or module housing). The groove-like recess of the end cap (also called the inner groove of the end cap) is larger in both width (longitudinal length) and thickness (short-axis length) than the outer dimensions of the insertion area of ​​the flat plate filter. The longitudinal and short-axis lengths of the recess define the effective space of the recess. Therefore, the outer width and thickness of the axial end face of the flat plate filter are smaller than the longitudinal and short-axis lengths of the recess of the end cap. This allows the flat plate filter to be inserted into the recess of the end cap without the inner wall of the recess contacting the radial sides of the filter. In other words, when inserting the filter into the recess, the inner wall of the recess and the radial sides of the filter do not come into contact.

[0008] Therefore, the recess in the end cap has an effective space that is wider (longitudinal length) and thicker (short-axis length) than the outer dimensions of the insertion area of ​​the flat filter. As a result, there is an open gap between the inner wall of the recess in the end cap and the radial side surface of the flat filter, and the width of this gap is usually 0.7 to 1.5 mm. This open gap is usually filled with potting adhesive. The function of the potting adhesive is to fill (pot) the gap and enable a seal, and to fix (bond) the end cap and filter to each other, forming a permanent and strong connection that cannot be separated.

[0009] This permanent and robust connection between the flat plate filter and the end cap must be secure, especially during backwashing when forced flow reversal causes liquid to be forced into the filtrate channel.

[0010] Typically, fluid materials such as epoxy resin or polyurethane are used as potting adhesives. The fluid material is injected into the opening gap from the adhesive inlet by gravity (i.e., it flows into the depths of the gap by gravity) and fills the entire gap (injection stage). After that, the potting adhesive needs to harden (hardening stage). The second end cap cannot be attached to the opposite end face of the flat filter until the injection and hardening stages of the potting material for the first end cap are complete. Otherwise, when the flat filter is moved, the potting material will flow out from the gap of the first end cap. The completed unit consists of three elements: the flat filter, the hardened potting adhesive, and the end cap. This sealing principle is described, for example, in reference WO 2007 128 565 A2.

[0011] The second potting approach is described, for example, in reference WO 2010 015 374 A1. This approach is similar to the one described above in that a fluid material (such as epoxy resin or polyurethane) is injected into the opening gap and flows down to the depths of the gap by gravity, filling the entire gap.

[0012] The second difference in the potting approach lies in the omission of end caps. Instead, the potting adhesive also functions as an end cap. In other words, the potting material is molded to a shape that not only fills the opening gap but also collects filtrate from the filtrate channels of the plate filter and discharges it through the outlet to a larger collection body (e.g., pipe, hose, module housing). To omit the end caps, the cured potting adhesive must have sufficient dimensional stability. Therefore, the finished unit consists of two elements: the plate filter and the dimensionally stable, cured potting adhesive. To manufacture the finished unit, a potting mold is used instead of end caps, and the internal dimensions of the potting mold determine the external shape of the cured potting adhesive.

[0013] To prevent the potting adhesive from sticking to the potting mold, a release agent such as silicone oil is used. For this reason, all inner surfaces of the potting mold are wetted with the release agent before potting. Once cured, the potting adhesive adheres firmly to the flat filter but not to the potting mold (which has been wetted with the release agent beforehand). In the so-called demolding process, the potting mold is removed from the cured potting adhesive, and the removed mold is usually reused in another molding process. Therefore, the potting mold is a reusable production tool component.

[0014] These two approaches share a common drawback: they rely on gravity-flow (gravity potting). That is, the potting adhesive must be a material that flows under gravity. Therefore, during the potting process, the end caps and flat filters must be positioned so that the fluid material can flow into the gaps due to gravity and fill them. Consequently, simultaneously potting the two end caps attached to both ends of a flat filter is difficult. To pot the second end cap, one must wait until the fluid material in the first end cap has hardened enough that it will not flow out even when the flat filter is rotated 180°. Therefore, the manufacturing process is considerably time-consuming.

[0015] Because flat plate filters have a flat shape and relatively large manufacturing tolerances, it has been impossible to achieve conventional radial or axial sealing principles by enclosing them in a housing using ring-shaped rubber seals or other shaped seals. This sealing principle is used, for example, in ceramic circular filters. In circular filters, because the manufacturing tolerances are small, the (relatively) perfectly circular shape of the filter uniformly presses the inserted seal against the seal housing, resulting in a permanently reliable seal. To succeed with this sealing principle, a shape dimensional tolerance of a fraction of a millimeter is usually required. However, ceramic flat plate filters typically have large manufacturing tolerances of up to 1 mm. Therefore, since a fluid potting material can perfectly compensate for any dimensional deviation (shape manufacturing tolerance) of the ceramic flat plate filter, only the sealing principle using a potting material has been realized.

[0016] CN 111 013 393 A shows a set comprising a flat ceramic membrane and an end cap configuration consisting of a water-receiving cap and an elastic sealing sleeve that seals and receives the ceramic membrane.

[0017] CN 207 694 609 U describes a set comprising a flat ceramic film and a rigid end cap, wherein the film is inserted into an elastic compartment structure and bonded to the end cap via an adhesive region. [Overview of the Initiative]

[0018] In view of this background, the present invention aims to provide a sealing method for ceramic plate filters and the necessary apparatus therefor, characterized by better implementability, in particular by shorter manufacturing time (assembly time).

[0019] This objective is achieved by a set comprising a ceramic plate filter, a flexible end cap, and an adhesive as described in claim 1, a plate filter having a flexible end cap as described in claim 9, a flexible end cap as described in claim 10, and a method of radially sealing a ceramic plate filter with a flexible end cap as described in claim 12.

[0020] The set comprises a ceramic plate filter, a flexible end cap, and an adhesive. The plate filter has two axial end faces and radial sides. Inside, a filtrate channel extends along the plate filter surface and opens at at least one axial end face of the plate filter. The end cap is configured to be attached to the end face end region of the plate filter and is configured to be permanently fixed to the plate filter in the attached state by adhesive, and has at least one filtrate outlet and a filtrate collection channel. In the attached state, the filtrate supplied from the filtrate channel of the plate filter is collected in the filtrate collection channel and led to at least one filtrate outlet. The end cap is formed of an elastic material and has groove-like recesses. In the expanded state, the recesses can accommodate the insertion region of the plate filter, and in the non-expanded state, the recesses have an effective space of the same size as or smaller than the insertion region of the plate filter. In the installed state, the insertion area of ​​the flat plate filter is received in the recess of the end cap, and adhesive is introduced radially and circumferentially between the radial side surfaces of the insertion area of ​​the flat plate filter and the inner wall of the recess of the end cap. In the installed state, the end cap, together with the adhesive, forms a radial seal between the inner wall of the recess and the radial side surfaces of the insertion area of ​​the flat plate filter.

[0021] The effective space of the groove-shaped recess in the flexible end cap is the same size as or smaller than the insertion area of ​​the flat plate filter. That is, before inserting the flat plate filter into the flexible end cap, the internal dimensions of the recess in the flexible end cap are the same as or smaller than the corresponding external dimensions of the insertion area of ​​the flat plate filter in terms of both the longitudinal length (internal width of the end cap) and the transverse length (internal thickness of the end cap). Therefore, in order to insert the filter insertion area into the recess, the recess needs to be expanded in both the longitudinal and transverse directions.

[0022] When the filter is inserted into the (expanded) recess, the flexible end cap elastically contracts. Therefore, in the installed state, there is no opening gap between the flat filter and the flexible end cap. Rather, the end cap (or the inner wall of the recess) is in circumferential contact with the radial sides of the flat filter.

[0023] In the installed state, adhesive is located between the flexible end cap and the radial side surface of the insertion area of ​​the flat filter. Due to the synergistic effect of the end cap's circumferential contact with the radial side surface of the flat filter and the adhesive action of the adhesive, the inner wall of the recess in the end cap seals the radial side surface of the insertion area of ​​the flat filter according to the radial sealing principle.

[0024] Furthermore, the adhesive can permanently fix the flexible end cap to the flat filter, especially during backwashing. Here, the adhesive does not need to be drawn into the gap by gravity as with conventional potting materials, and can be introduced at any position. Therefore, the waiting time for the injection and curing stages is eliminated before attaching another end cap to the opposite end face of the flat filter. Thus, the manufacturing time is significantly reduced by the present invention.

[0025] The adhesive is applied directly (e.g., in the form of an adhesive bead or dot) to the radial side surface in the insertion area of the flat filter and / or the inner wall of the recess of the end cap. The adhesive is usually applied with a thickness of 1 to 3 mm and is radially and uniformly distributed. To insert the flat filter into the end cap, before or after applying the adhesive, the recess of the end cap is expanded in the longitudinal and transverse directions (the inner width and inner thickness of the end cap are expanded).

[0026] This expansion is preferably carried out by an expansion device (expansion tool) that is inserted into the recess of the flexible end cap and expands (widens) the inner width and inner thickness of the end cap. By expanding the recess of the end cap, the size can be made larger than the insertion area of the flat filter. This ensures that when the flat filter is inserted into the recess, the inner wall of the recess and the applied adhesive bead do not come into contact or rub against each other. As soon as the insertion area of the flat filter is completely inserted into the expanded recess of the end cap (this final insertion depth is preferably 5 to 15 mm), the expansion ends. Then, the end cap elastically contracts, and the inner wall of the recess of the end cap comes into contact with the radial side surface in the insertion area of the flat filter.

[0027] Since the recess of the end cap (in the non-expanded state) is the same size as or smaller than the flat filter, when the expansion ends and the end cap elastically contracts, the applied adhesive (e.g., adhesive bead) is compressed and spreads uniformly over the contact area between the inner wall of the recess and the radial side surface of the flat filter.

[0028] When the adhesive cures, a strong unit that cannot be permanently separated by the end cap and the flat filter is formed. The adhesive prevents displacement and deformation of the end cap, thus providing the internal holding force required to ensure the seal. This eliminates the need to provide a housing that surrounds the outside for the seal.

[0029] According to the first preferred embodiment, the inner wall of the recess of the end cap has a protruding shoulder region, and in the state where the end cap is attached, the shoulder region abuts against or is pressed against the edge region of the axial end face of the insertion region of the flat filter, so that the end cap forms an axial seal with respect to the edge region of the flat filter.

[0030] Thus, in contrast to the conventional sealing method, the seal between the ceramic flat filter and the end cap is realized not only by a radial seal (with respect to the radial side surface of the flat filter) but also by an axial seal (with respect to the edge region of the axial end face of the flat filter). Therefore, a very permanent seal is realized, especially under the pressure conditions that occur during backwashing.

[0031] Preferably, the inner wall of the recess of the end cap has a circumferential recess for receiving an adhesive. This can make the attachment process easy and firm. This is because the recess functions as a kind of guide and assists in the uniform application of the adhesive. Furthermore, the adhesive (for example in the form of an adhesive bead) placed in the recess does not reach deep into the recess of the end cap, so the risk of "rubbing" of the adhesive that may occur when inserting the flat filter into the (expanded state) recess of the end cap can be further reduced. This is advantageous for the reliability of the process and the durability and sealing performance of the seal.

[0032] Furthermore, it is preferable that the end cap is formed of an elastic plastic having a Shore hardness A of 65 to 85 SHORE A, more preferably 70 to 80 SHORE A, and / or a plastic from the group of EPDM (ethylene-propylene-diene rubber), fluoroelastomer (especially Viton), TPE (thermoplastic elastomer), or polyurethane. The measurement of the Shore hardness A is performed in the conventional manner by indentation hardness measurement using a durometer, particularly in accordance with DIN EN ISO 868:2003-10 or ASTM D2240.

[0033] The adhesive preferably comprises an epoxy resin, polyurethane, silane-modified polymer, or methacrylate, and / or preferably has a viscosity of at least 6000 mPas at a temperature of 25°C (by Brookfield RVT measurement or cone-plate measurement).

[0034] According to a more preferred embodiment of the present invention, the effective space of the recess in the non-expanded state (of the end cap) is such that the inner width of the end cap is 70 to 290 mm and / or the inner thickness of the end cap is 1 to 6 mm, and the axial end face of the insertion area of ​​the ceramic plate filter is such that the outer width is 80 to 300 mm and / or the outer thickness is 3 to 8 mm. Thus, the width of the recess can be reduced by 10 mm and the thickness by 2 mm compared to a plate filter. This has proven to be a practical compromise between ease of assembly and sealing.

[0035] For certain applications, it is advantageous to have end caps having at least one filtrate outlet positioned on both end faces of a flat plate filter. This allows the filtrate to be discharged from both end faces of the flat plate filter. To achieve this, the filtrate channels of the flat plate filter extend along the surface of the flat plate filter and open at the two axial end faces of the flat plate filter. When the end cap of the present invention described above is designated as the first flexible end cap, it is preferable that the set includes a second flexible end cap. The second flexible end cap has the same design as the first flexible end cap, and in the installed state, both end caps are attached to both axial end faces of the flat plate filter.

[0036] On the other hand, in other applications, it may be advantageous for only one of the two end caps on the end face of a flat plate filter to have a filtrate outlet. In this way, the filtrate may be discharged only from the axial end face of the flat plate filter where the end cap with (at least one) filtrate outlet is located. In this case, the second end cap simply serves a sealing function.

[0037] For this purpose, it is preferable that the filtrate channels of the flat plate filter extend along the surface of the flat plate filter and open at the two axial end faces of the flat plate filter. The set includes a second flexible end cap, which is configured to be attached to the second end face region of the flat plate filter and is configured to be permanently fixed to the flat plate filter by adhesive, and has a filtrate collection channel that is in fluid communication with the filtrate channels of the flat plate filter when attached. The second end cap is made of an elastic material and has a groove-shaped recess. When the recess is expanded, it can receive the second insertion region of the flat plate filter, and when the recess is not expanded, it has an effective space of the same size as or smaller than the second insertion region of the flat plate filter (and therefore does not receive the second insertion region of the flat plate filter). When attached, the second insertion region of the flat plate filter is received in the recess of the second end cap, and adhesive is introduced radially around the radial side surface of the second insertion region of the flat plate filter and the inner wall of the recess of the second end cap. In the installed state, the second end cap, together with the adhesive, forms a radial seal between the inner wall of the recess and the radial side surface of the second insertion area of ​​the flat filter.

[0038] A flat plate filter fitted with the flexible end cap according to the present invention is made from the set of the present invention according to the above embodiment.

[0039] The flexible end cap of the present invention used in the set according to the above embodiment is configured to be attached to the end face region of a flat plate filter and is configured to be permanently fixed to the flat plate filter by adhesive, and has a filtrate collection channel (and optionally at least one filtrate outlet). The end cap is formed of an elastic material and has a groove-like recess, the recess in the expanded state can receive the insertion region of the flat plate filter, and the recess in the non-expanded state has an effective space of the same size as or smaller than the insertion region of the same flat plate filter (and therefore does not receive the insertion region of the flat plate filter in the non-expanded state). The effective space of the recess in the non-expanded state has a longitudinal dimension of at least 5 times, in particular at least 10 times, its transverse dimension.

[0040] It is preferable that the flexible end cap has retaining elements positioned on opposite sides of the recess. This allows the recess to be easily expanded (by hand or mechanically) in the longitudinal or transverse direction. The retaining elements may be removed during the production process after the expansion process is complete.

[0041] A method is used to radially seal a ceramic plate filter with a flexible end cap, which includes the following steps. A) To prepare a set according to the present invention comprising a ceramic plate filter, a flexible end cap, and an adhesive, B) Applying adhesive in a radial pattern around the recess of the end cap, and / or applying adhesive to the radial side surfaces in the insertion area of ​​the flat filter, C) Expanding the recess of the flexible end cap in the longitudinal and transverse directions of the recess, D) Inserting the insertion area of ​​the flat plate filter into the enlarged recess of the end cap, E) As the expansion of the recess is completed, the flexible end cap is elastically contracted to form a radial seal between the inner wall of the recess and the radial side surface of the insertion area of ​​the flat filter.

[0042] According to a preferred embodiment of the method of the present invention, in step C, the expansion of the recess of the flexible end cap in the longitudinal and / or transverse direction is performed by pulling apart the retaining elements attached to the opposite side of the recess, and / or the expansion of the recess of the flexible end cap in the longitudinal and / or transverse direction of the recess is performed using an expansion device that engages with the recess or acts appropriately on the recess. In particular, a combination of the above two is also possible. For example, the expansion of the recess of the end cap in a first direction of the longitudinal and transverse directions is performed by pulling each retaining element apart from one another, and the expansion in a second direction of the longitudinal and transverse directions is performed by an expansion device that engages with (or acts appropriately on) the recess.

[0043] Furthermore, in step D, inserting the insertion area of ​​the flat plate filter into the expanded recess is performed by inserting the flat plate filter until the end face of the flat plate filter abuts against or presses against the end cap, in particular the end face of the flat plate filter abuts against or presses against the protruding shoulder region of the inner wall of the recess of the end cap.

[0044] Furthermore, in step D, when inserting the insertion area of ​​the flat filter into the expanded recess, it is advantageous that the adhesive applied radially and circumferentially to the recess of the end cap does not come into contact with the flat filter, and / or that the adhesive applied radially and circumferentially to the radial side surface of the flat filter does not come into contact with the end cap.

[0045] According to a more preferred embodiment, the method further includes the following steps: F) Press the flexible end cap radially against the flat filter.

[0046] By pressing the flexible end cap onto the flat filter (by hand or mechanically), the contraction of the end cap is promoted, which in turn promotes the uniform spreading and "expanding" of the adhesive in the contact area between the inner wall of the recess and the radial side surface of the flat filter.

[0047] Illustrative embodiments of the present invention will be described in detail below with reference to the drawings. [Brief explanation of the drawing]

[0048] [Figure 1A] A perspective view of a conventional ceramic flat plate filter. [Figure 1B] Front view of a conventional ceramic flat plate filter. [Figure 2] This diagram shows a dimensionally stable (rigid) end cap and flat filter at various assembly stages using conventional technology, along with potting adhesive. [Figure 3A] A diagram showing a first embodiment of the present invention, including a flat filter, a flexible end cap, and an adhesive, at various assembly stages. [Figure 3B] A diagram showing a first embodiment of the present invention, including a flat filter, a flexible end cap, and an adhesive, at various assembly stages. [Figure 3C] A diagram showing a first embodiment of the present invention, including a flat filter, a flexible end cap, and an adhesive, at various assembly stages. [Figure 3D] A diagram showing a first embodiment of the present invention, including a flat filter, a flexible end cap, and an adhesive, at various assembly stages. [Figure 4A] A perspective view of a second embodiment of the present invention set having two end caps. [Figure 4B] A perspective view of a second embodiment of the present invention set having two end caps. [Figure 5A] This is a perspective view of a second embodiment of the present invention, in which the end cap is in an extended state and adhesive is applied to the flat filter. [Figure 5B] This is a perspective view of a second embodiment of the set of the present invention, in which the end cap is in an extended state and adhesive is applied to the inner wall of the recess. [Figure 6A]This figure shows a flexible end cap along with an expansion device that engages with the end cap, with the end cap shown in its non-expanded (closed) state. [Figure 6B] This figure shows a flexible end cap along with an expansion device that engages with the end cap, with the end cap shown in the expanded (open) state. [Modes for carrying out the invention]

[0049] Figures 1A to 2 show the prior art already described, while Figures 3A to 6B show the present invention.

[0050] Figures 3A to 3D each show the same first embodiment of set 9 according to the present invention, with each figure showing a different assembly state. The ceramic plate filter 1 itself corresponds to the prior art described in Figure 2 and has two axial end faces 4 extending over (outer dimensions) thickness A and (outer dimensions) width B (see Figures 4A and 4B). The radial side faces 2 extend along the length C (longitudinal length of the filter) of the plate filter 1. The plate filter 1 has an insertion area 5 in the region of the lower axial end face 4. Inside the plate filter 1, filtrate channels (not shown in Figures 3A to 3D) extend along the plate filter surface and open at both axial end faces 4 of the plate filter 1.

[0051] The flexible end cap 10 is made of an elastic material and has a filtrate outlet 11, a filtrate collection channel 12, and a groove-shaped recess 14 formed by a peripheral wall 13. Inside the wall 13 of the recess 14 of the end cap (the inner wall of the recess), there is a semicircular recess 15 for receiving the adhesive 16, although the shape of the recess may be other shapes. The effective space of the recess 14 in the non-expanded state shown in Figure 3A has an end cap inner width E (see Figures 4A and 4B) and an end cap inner thickness D. The effective space of the recess 14 in the non-expanded state is the same size as or smaller than the insertion area 5 of the flat filter 1. That is, the end cap inner width E is less than or equal to the width B of the flat filter 1, and the end cap inner thickness D is less than or equal to the thickness A (of the flat filter 1). A shoulder region 17 is provided at the bottom of the inner wall of the recess 14. The insertion depth F is defined as the distance from the upper end 18 of the wall 13 of the recess 14 to the shoulder region 17.

[0052] In Figure 3B, the recess 14 of the end cap 10 is in an expanded state (by an expansion device not shown). In this state, the wall 13 extends outward at its upper end 18 more than the lower region of the recess 14, and the recess 14 is funnel-shaped. In this expanded state, the effective space of the recess 14 at the upper end 18 is larger than the insertion region 5 of the flat filter 1. Adhesive 16 is applied to the radial side surface 2 of the flat filter in the form of adhesive beads.

[0053] Figure 3C shows the inserted flat filter 1 in the end cap 10. The shoulder region 17 of the end cap 10 is in contact with the edge region 4R of the axial end face 4 of the insertion region 5 of the flat filter 1. The flat filter 1 is inserted with the end cap 10 expanded. This allows the insertion region 5 of the flat filter to be inserted quickly and easily without the radial sides 2 (or adhesive 16) of the flat filter 1 coming into contact with the inner wall of the recess 14.

[0054] Subsequently, the expansion of the recess 14 in the end cap 10 is completed. The end cap 10 (specifically the recess 14) elastically contracts to the shape shown in Figure 3D. The wall 13 of the recess 14 radially and circumferentially contacts the insertion area 5 of the flat filter 1, and the (compressed) adhesive 16 is located between the wall 13 and the flat filter 1. Once the adhesive 16 hardens, the end cap 10 is permanently fixed to the flat filter 1.

[0055] In this mounting state, the end cap 10, together with the (cured) adhesive 16, forms a radial seal between the inner wall of the recess 14 and the radial side surface 2 in the insertion area 5 of the flat filter 1. The shoulder area 17 of the end cap 10 abuts against the edge area 4R of the axial end face 4 of the flat filter 1, forming an axial seal with respect to the flat filter 1. The filtrate supplied from the filtrate channel 3 of the flat filter 1 is collected in the filtrate collection channel 12 and guided to the filtrate outlet 11.

[0056] The second embodiment of the present invention, shown in Figures 4A and 4B, has two flexible end caps 10.1 and 10.2, each having a filtrate outlet 12, instead of one end cap. Therefore, the filtrate can be discharged from the ceramic plate filter 1 through both filtrate outlets 12. The upper end cap 10.1 is in the installed state, and the lower end cap 10.2 is in the uninstalled and unextended state. As can be seen from the perspective view, the ceramic plate filter 1 has a plate shape with rounded edges. The recesses of the end caps 10.1 and 10.2 have corresponding shapes such that (in the installed state) the walls 13 abut radially and circumferentially against the radial side surfaces 2 of the plate filter 1.

[0057] Figures 5A and 5B show a second embodiment of Figures 4A and 4B, where the lower end cap 10.2 is in an extended state. Two different possibilities regarding the application of the adhesive 16 are shown. In Figure 5A, the adhesive 16 (in the form of an adhesive bead) is applied radially and circumferentially to the radial side surface 2 (in the insertion region 5) of the flat filter 1. On the other hand, in Figure 5B, the adhesive 16 (in the form of an adhesive bead) is applied radially and circumferentially to the circumferential recess 15 on the inner wall of the recess 14 of the (lower) end cap 10.2.

[0058] Figures 6A and 6B show an example of expanding a recess 14 of a flexible end cap 10 using an expansion device 19 (expansion tool). The expansion device 19 has a pair of lever plates 20 and a pair of lever plates 21. The width lever plate 20 expands the width of the recess 14, and the thickness lever plate 21 expands the thickness of the recess 14. The lever plates 20 and 21 are first inserted into the recess 14 as shown in Figure 6A, and then simultaneously tilted outward. Consequently, the walls 13 of the recess 14 expand radially, as shown in Figure 6B, and the recess 14 becomes expanded.

Claims

1. A set (9) comprising a ceramic flat filter (1), a flexible end cap (10), and an adhesive (16), The flat plate filter (1) has two axial end faces (4) and radial side faces (2), and inside it, a filtrate channel (3) extends along the surface of the flat plate filter and is open at at least one of the axial end faces (4) of the flat plate filter (1). The end cap (10) is configured to be attached to the end face region of the flat plate filter (1), and is configured to be permanently fixed to the flat plate filter (1) in the attached state by the adhesive (16), and has at least one filtrate outlet (11) and a filtrate collection channel (12), and in the attached state, the filtrate supplied from the filtrate channel (3) of the flat plate filter (1) is collected in the filtrate collection channel (12) and guided to the at least one filtrate outlet (11), The end cap (10) is made of an elastic material and has a groove-shaped recess (14). In the expanded state, the recess (14) is capable of receiving the insertion region (5) of the flat plate filter (1). In the non-expanded state, the recess (14) has an effective space that is the same size as or smaller than the insertion region (5) of the flat plate filter (1). In the aforementioned mounting state, the insertion region (5) of the flat plate filter (1) is received in the recess (14) of the end cap (10), and the adhesive (16) is introduced radially and circumferentially between the radial side surface (2) of the insertion region (5) of the flat plate filter (1) and the inner wall of the recess (14) of the end cap (10). In the above-mentioned mounting state, the end cap (10), together with the adhesive (16), forms a radial seal between the inner wall of the recess (14) and the radial side surface (2) in the insertion region (5) of the flat filter (1), as set (9).

2. The inner wall of the recess (14) of the end cap (10) has a protruding shoulder region (17), In the state in which the end cap (10) is attached, the shoulder region (17) is in contact with or pressed against the edge region (4R) of the axial end face (4) of the insertion region (5) of the flat filter (1), and the end cap (10) forms an axial seal with respect to the flat filter (1) at the edge region (4R), the set (9) according to claim 1.

3. The set (9) according to claim 1 or 2, wherein the inner wall of the recess (14) of the end cap (10) has a circumferential recess (15) for receiving the adhesive (16).

4. The set (9) according to any one of claims 1 to 3, wherein the end cap (10) is formed from an elastic plastic having a Shore hardness A of 65 to 85 SHORE A, preferably 70 to 80 SHORE A, and / or from a plastic from the group consisting of EPDM, fluoroelastomers (particularly Viton), TPE, and polyurethane.

5. The set (9) according to any one of claims 1 to 4, wherein the adhesive (16) comprises an epoxy resin, polyurethane, silane-modified polymer, or methacrylate and / or has a viscosity of at least 6000 mPas at a temperature of 25°C.

6. The effective space of the recess (14) in the non-expanded state has an end cap inner width (E) of 70 to 290 mm and / or an end cap inner thickness (D) of 1 to 6 mm. The set (9) according to any one of claims 1 to 5, wherein the axial end face (4) of the insertion region (5) of the ceramic flat plate filter (1) has an outer width (B) of 80 to 300 mm and / or an outer thickness (A) of 3 to 8 mm.

7. The filtrate channel (3) of the flat plate filter (1) extends along the surface of the flat plate filter and opens at the two axial end faces (4) of the flat plate filter (1). The set (9) according to any one of claims 1 to 6, wherein the set (9) comprises a flexible second end cap (10) when the end cap (10) is designated as the first end cap (10), the second end cap (10) having the same design as the first end cap (10), and in the mounted state, the two end caps are attached to the opposing axial end faces (4) of the flat plate filter (1).

8. The filtrate channel (3) of the flat plate filter (1) extends along the surface of the flat plate filter and opens at the two axial end faces (4) of the flat plate filter (1). The set (9) comprises a flexible second end cap (10), The second end cap (10) is configured to be attached to the second end face region of the flat plate filter (1), and is configured to be permanently fixed to the flat plate filter (1) in the attached state by the adhesive (16), and has a filtrate collection channel (12) that is in fluid communication with the filtrate channel (3) of the flat plate filter (1) in the attached state. The second end cap (10) is made of an elastic material and has a groove-shaped recess (14), the recess (14) in the expanded state is capable of receiving the second insertion region (5) of the flat plate filter (1), and the recess (14) in the non-expanded state has an effective space that is the same size as or smaller than the second insertion region (5) of the flat plate filter (1). In the aforementioned mounting state, the second insertion region (5) of the flat filter (1) is received in the recess (14) of the second end cap (10), and the adhesive (16) is introduced radially and circumferentially between the radial side surface (2) of the second insertion region (5) of the flat filter (1) and the inner wall of the recess (14) of the second end cap (10). In the aforementioned mounting state, the second end cap (10), together with the adhesive (16), forms a radial seal between the inner wall of the recess (14) and the radial side surface (2) in the second insertion region (5) of the flat filter (1), according to any one of claims 1 to 6 (9).

9. A flat plate filter (1) with a flexible end cap (10) attached, made from a set (9) according to any one of claims 1 to 8.

10. A flexible end cap (10) used in a set (9) according to any one of claims 1 to 8, The end cap (10) is configured to be attached to the end face region of the flat plate filter (1), and is configured to be permanently fixed to the flat plate filter (1) in the attached state by adhesive (16), and has a filtrate collection channel (12), The end cap (10) is made of an elastic material and has a groove-shaped recess (14). In the expanded state, the recess (14) is capable of receiving the insertion region (5) of the flat plate filter (1). In the non-expanded state, the recess (14) has an effective space that is the same size as or smaller than the insertion region (5) of the same flat plate filter (1). The effective space of the recess (14) in the non-expanded state is a flexible end cap (10) whose longitudinal length is at least five times, and particularly at least ten times, greater than its transverse length.

11. The flexible end cap (10) according to claim 10, wherein the end cap (10) has a retaining element located on the opposite side of the recess (14).

12. A method for radially sealing a ceramic flat filter (1) using a flexible end cap (10), wherein the method is: A) A step of preparing a set (9) comprising a ceramic flat filter (1), a flexible end cap (10), and an adhesive (16) as described in any one of claims 1 to 8, B) The steps of applying the adhesive (16) to the recess (14) of the end cap (10) in a radial manner, and / or applying the adhesive (16) to the radial side surface (2) in the insertion area (5) of the flat filter (1), C) The step of expanding the recess (14) of the flexible end cap (10) in the longitudinal and transverse directions of the recess (14), D) Inserting the insertion area (5) of the flat plate filter (1) into the expanded recess (14) of the end cap (10), E) A method comprising the step of elastically contracting the flexible end cap (10) as the expansion of the recess (14) is completed, thereby forming a radial seal between the inner wall of the recess (14) of the end cap (10) and the radial side surface (2) of the insertion region (5) of the flat plate filter (1).

13. In step C, Expanding the recess (14) of the flexible end cap (10) in the longitudinal and / or transverse directions is done by pulling away the retaining element located on the opposite side of the recess (14), and / or The method according to claim 12, wherein the expansion of the recess (14) of the flexible end cap (10) in the longitudinal and / or transverse direction is performed by an expansion device (19) that engages with or acts on the recess (14).

14. In step D, The method according to claim 12 or 13, wherein the insertion area (5) of the flat plate filter (1) is inserted into the expanded recess (14) of the end cap (10) by inserting the flat plate filter (1) until the end face (4) of the flat plate filter (1) abuts against or is pressed against the end cap (10), and the end face (4) of the flat plate filter (1) abuts against and / or is pressed against the protruding shoulder region (17) of the inner wall of the recess (14) of the end cap (10).

15. In step D, when inserting the insertion area (5) of the flat plate filter (1) into the expanded recess (14) of the end cap (10), The adhesive (16) applied radially around the recess (14) of the end cap (10) does not come into contact with the flat filter (1), and / or The method according to any one of claims 12 to 14, wherein the adhesive (16) applied radially around the radial side surface (2) of the flat plate filter (1) does not come into contact with the end cap (10).

16. The method according to any one of claims 12 to 15, further comprising the step of F) pressing the flexible end cap (10) radially against the flat plate filter (1).

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