Filtering means for filtering units with backwashing

Abstract

A filter member (10) for filter units (90) with backwashing, the filter member (10) being annular and comprising a filter medium (22) between an inner edge (24) and an outer edge (26) and an inner face (20) and an outer face (21) on either side of the filter medium (22). The filter member (10) is adapted to be assembled against a first identical filter member (10') so that their respective inner faces (20, 20') facing define a space delimited in the periphery by the respective ribs (28, 28') in contact. One of the inner edge (24) and the outer edge (26) has a passage (30) in communication with each of the sectors on the inner face (20). The outer face (21) has a key (36) for pairing the filter member (10) in a given position with respect to a second identical filter member (10") so that the passage (30") of the second identical filter member (10") is offset with respect to the passage (30) of the filter member (10).

Description

Technical Field

[0001] This disclosure relates to filter units with automatic backwashing. More particularly, this disclosure relates to improvements in the backwashing efficiency of such filter units. Background Technology

[0002] International application WO 2012 / 028824 describes a filter unit comprising at least two filter members, each filter member having an inner surface, an outer surface, a filter screen, two concentric circular edges (an inner edge and an outer edge, respectively, the filter screen extending between the inner and outer edges), and radial ribs at least on the inner surface, the radial ribs extending between the concentric edges and distributed circumferentially to form different sectors on the inner surface. The filter members are configured to be assembled abutted against each other such that their respective inner surfaces face each other to define a space between them, wherein the radial ribs defining the sectors form circumferential compartments in the space. At least one of the inner and outer edges has a passageway communicating with a corresponding sector in the sector. The filter members are stacked axially between a first cover and a second cover.

[0003] By stacking a selected number of filter element pairs, the desired filtration area is obtained for the intended application. Typically, the fluid used for filtration permeates into the stack via passages at the inner edge, passes through the filter screen, and, once purified, exits via other passages defined at the outer edge. Naturally, the fluid flow through the filter screen can be reversed or arranged in some other manner.

[0004] The filter described in this disclosure also includes a separator arranged coaxially with the filter element, the separator having different distribution columns, and a rotary backwash distributor located at a first cover. The rotary backwash distributor has a gate with a discharge opening and is mounted to rotate such that the discharge opening periodically and selectively communicates with each distribution column, thereby establishing communication between each distribution column periodically and selectively between the discharge opening and a corresponding passage in the passage.

[0005] In this manner, the fluid flow is periodically reversed in sectors corresponding to the passageway in fluid communication with the discharge opening, which allows backwashing to be performed in these sectors due to the pressure gradient across the filter screen (i.e., the pressure gradient between the outer and inner sides). The fluid used for backwashing is then discharged through the discharge opening.

[0006] In some applications (typically water-based), the pressure gradient may be insufficient to guarantee a sufficiently high backwash flow and therefore insufficient to guarantee complete backwashing of the filter. Increasing the total backwash flow is not desirable, as it represents a loss of clean flow. This loss can be compensated for by increasing the inlet flow, but this would mean oversizing upstream units (such as pumps, heat exchangers, and other accessories).

[0007] Therefore, there is a need to improve the efficiency of backwashing. One such need is for filters used in water-based applications, which generally operate at lower pressures than those used for other fluids, such as oil. Therefore, new types of filter units or new components thereof are required. Summary of the Invention

[0008] In this respect, the present disclosure further relates to a filter element for a filter unit having a backwash, the filter element being annular and including an inner edge, an outer edge, and a filter medium extending between the inner and outer edges, the filter element having an inner surface and an outer surface on either side of the filter medium, wherein, on the inner surface, ribs extending between the inner and outer edges are circumferentially distributed to form sectors, wherein the filter elements are adapted to be assembled against first identical filter elements such that their respective inner surfaces define spaces circumferentially separated by the contact of the respective ribs of the inner surfaces, wherein the first of the inner and outer edges has a passageway communicating with each of the sectors on the inner surface, and wherein the outer surface has a key for pairing a filter element in a given position relative to a second identical filter element, the key being arranged such that the passageway of the second identical filter element is offset relative to the passageway of the filter element.

[0009] The filter media may extend over part or all of the distance between the inner and outer edges. One side of the filter media defines the inner surface of the filter element, while the opposite side defines the outer surface of the filter element. The filter element may be generally flat.

[0010] The first and second identical filter elements are identical to the disclosed filter element (also referred to as the "reference" filter element to avoid ambiguity) at least in terms of the described features, but it should be understood that they may differ in other features.

[0011] The inner surface of the reference filter element is thus configured to assemble onto the inner surface of the first identical filter element. The outer surface of the reference filter element is thus configured to assemble onto the outer surface of the second identical filter element. Therefore, a stack can be achieved using identical filter elements, each filter element being inverted relative to its adjacent filter element. However, although they can be assembled onto the same filter element, the inner and / or outer surfaces of the reference filter element can also be assembled onto different filter elements.

[0012] Ribs defined on the inner surface allow for isolation of sectors used for backwashing. No separation is required on the outer surface. At least one passage may be provided on the outer surface, for example, on the second of the inner and outer edges, for a purge fluid outlet and a backwash inlet. Conversely, on the inner surface, the second of the inner and outer edges may lack a passage, such that fluid entering a sector via the passage must cross the filter media to exit that sector.

[0013] Because the connecting passages to each sector on the inner surface are all located on the first of the inner and outer edges, the direction of the flow to be filtered is the same in all sectors on the inner surface. Therefore, the outer surface can be simplified. Due to these two considerations, the flow is distributed more evenly, and pressure loss is reduced. Furthermore, because the direction of the flow to be filtered is the same in all sectors on the inner surface, the material forming the inner surface is regularly distributed during the manufacturing of the filter element, reducing the possibility of manufacturing defects.

[0014] A key is an element that provides a bonding connection between the corresponding outer surfaces of a reference filter element and a second identical filter element. Therefore, the key predetermines the relative position of the second identical filter element (e.g., at an angle) with respect to the reference filter element. The key may include physical elements that provide physical cooperation.

[0015] The key can be located between the inner and outer edges to reduce the volume of the filter element.

[0016] The offset can be an offset in the circumferential direction of the annular filter element.

[0017] Because the key arrangement causes the passageways of the second identical filter element to be offset relative to the passageways of the filter element, the passageways of adjacent filter elements can be isolated for sequential (and no longer simultaneous) backwashing. Therefore, the number of sectors backwashed simultaneously is reduced. Consequently, the backwash specific flow rate (i.e., the backwash flow per unit surface area of ​​filter media) in the backwash sector increases without increasing the total backwash flow (which would require over-sizing the filter, as explained above) or increasing the number of sectors (which would reduce the total filter surface area due to the space occupied by the ribs). Therefore, backwash efficiency is improved.

[0018] In some embodiments, the key is configured to prevent the outer surface from being assembled to the inner surface of a second identical filter element. For example, the key may be mechanically incompatible with the inner surface of the second identical filter element. This ensures proper assembly of the filter and, consequently, proper positioning of the passageways.

[0019] In some embodiments, the inner surface includes a first indicator and a second indicator for pairing with a corresponding second indicator and a corresponding first indicator on the inner surface of a first identical filter member, respectively, wherein the key is offset relative to the axis of symmetry that transforms the first indicator into the second indicator.

[0020] As explained above, the inner surface of the reference filter member is adapted to abut against the inner surface of the first identical filter member. The relative position of the reference filter member and the first identical filter member is determined by the pairing of a corresponding first indicator and a corresponding second indicator. The first and second indicators can provide a bonding connection.

[0021] Because a first indicator in one filter element pairs with a second indicator in another filter element, a symmetry exists within the same filter element that transforms the first indicator into the second indicator. This symmetry has an axis, and the key is offset relative to this axis. Therefore, the key of the reference filter element shifts relative to the key of the first identical filter element. This causes the outer surfaces of the filter elements to gradually shift relative to each other, causing the pathways of subsequent filter elements to also gradually shift.

[0022] In some embodiments, the ribs extend beyond the filter medium to the outside, and the thickness of the ribs on the outer surface is less than the thickness of the ribs on the inner surface. That is, ribs are provided on the outer surface, extending onto the ribs on the inner surface. However, the thickness of the ribs on the outer surface is less than the thickness of the ribs on the inner surface. Therefore, the pressure loss on the outer surface is reduced without compromising the mechanical robustness of the filter element.

[0023] In some embodiments, the key faces at least one of the ribs in the direction across the filter medium. The key is located on the outer surface, while the ribs are located on the inner surface, but maximizing the surface area of ​​the filter medium available for filtering the fluid flow by having the key face at least one of the ribs in the direction across the filter medium. Filtration and backwashing efficiency are thus improved. If applicable, the key may be located on the outer ribs.

[0024] In some embodiments, the filter medium includes a mesh. In some embodiments, the mesh is inclined from one end of the inner edge to the opposite side of the outer edge, which helps to increase the filter surface and reduce pressure loss.

[0025] This disclosure further relates to a filter element for a filter unit having a backwash, the filter element being annular and including an inner edge, an outer edge, and a filter medium extending between the inner and outer edges to define a pre-filter chamber, at least the pre-filter chamber being circumferentially divided into sectors, at least one of the inner and outer edges having a passageway communicating with each of the sectors, wherein the filter element also has a key for pairing filter elements in a given position relative to the same filter element, the key being arranged such that the passageway of the same filter element is offset relative to the passageway of the filter element.

[0026] The filter element may include a pair of facing filter members as described above, such as a reference filter member and a first identical filter member. In this case, a pre-filtration chamber may be defined between the respective inner surfaces of the facing filter members. Furthermore, the identical filter element may include a second identical filter member. In other embodiments, the filter element may not be divisible into two filter members.

[0027] Because the keys are arranged such that the passageways of the same filter element are offset relative to the passageways of the filter element, backwashing efficiency is improved for the same reasons as those previously detailed.

[0028] In some embodiments, the key is located outside the pre-filtration chamber.

[0029] In some embodiments, the keys are located at different positions on two opposite sides of the filter element. Therefore, the filter element assembled on one side of the reference filter element may have a different position than the filter element assembled on the opposite side of the reference filter element, and / or both may have a different position than the reference filter element itself. This results in a better distribution of the flow path, which makes backwashing more efficient.

[0030] This disclosure further relates to a filtration section for a filter unit having backwashing, wherein the filtration section is a filter member or filter element as previously described.

[0031] In some embodiments, the key includes a protrusion and a recess, wherein the protrusion is configured to engage in the recess of the same filter portion. This ensures correct positioning.

[0032] If applicable, protrusions and / or recesses may be blind to avoid creating channels in which filtered fluid will mix with unfiltered fluid.

[0033] In some embodiments, the offset is a non-integer multiple of the sector. A non-integer multiple is a multiple less than or greater than 1, and is not an integer: for example, 1 / 2, 1 / 3, 3 / 2, 2.4, etc. The offset, measured in one, is the offset that transforms a sector into an adjacent sector, and in particular, the offset that transforms a path into an adjacent path. Therefore, because the offset is a pitch measured in non-integer multiples of the sector, the offset of the path is precisely and consistently controlled.

[0034] In some embodiments, the key makes the filter section non-rotationally symmetrical. That is, there is no rotation greater than 0° and less than 360° that would cause the key to transform itself by such an angle. Therefore, the unique positioning of the successive outer surfaces of the filter section is guaranteed.

[0035] This disclosure further relates to a filter assembly for a filter unit with backwashing, the filter assembly including a sleeve and a plurality of filter sections stacked on top of each other, wherein each filter section has a filter medium and a plurality of passages for directing fluid to the filter medium, the passages being open in separated sectors, wherein the filter sections are bonded relative to the sleeve such that a passage in one of the filter sections is offset relative to a passage in an adjacent filter section.

[0036] As mentioned earlier, the filtration section can be a filter element or a filter component, and can have some or all of the properties described above.

[0037] The sleeve can be assembled around the stack of filter sections or (when the filter section is annular) inside the stack of filter sections. The sleeve itself can be annular.

[0038] Note that the filter sections do not need to be bonded relative to each other, only to a common element (in this case, the sleeve). Hybrid solutions are also envisioned, in which some filter sections are bonded relative to each other and some filter sections are bonded to the sleeve.

[0039] Because the filter section is bonded to the sleeve, the passage of one of the filter sections is offset relative to the passage of the adjacent filter section, improving backwashing efficiency for the same reasons as those previously detailed.

[0040] In some embodiments, the sleeve has orifices facing the passage, which are circumferentially offset along the longitudinal direction of the sleeve. That is, an orifice at one longitudinal position is circumferentially offset from an orifice at another longitudinal position. In addition to matching the passage of the filter section, circumferentially offsetting the passage along the longitudinal direction mechanically strengthens the sleeve.

[0041] Alternatively, or additionally, the orifice may be elongated to accommodate different locations within the filter path.

[0042] This disclosure further relates to a filter unit that includes a plurality of filter elements, or a plurality of filter components, or a plurality of filter sections, or a filter assembly as previously described. The filter unit also includes a rotary backwash distributor configured to selectively isolate pathways to allow backwashing in corresponding sectors.

[0043] The rotary backwash dispenser may have an opening that periodically and selectively communicates with at least one of the passages, for example, a passage aligned perpendicular to the direction of movement of the rotary backwash dispenser.

[0044] This disclosure further relates to a filter comprising a housing and a plurality of filter elements stacked between a first cover and a second cover, wherein the first cover rests against the housing in the stacking direction of the filter elements, and wherein the filter further comprises a cover backing coupled to the second cover by a return system configured to return the second cover toward the first cover, wherein the cover backing rests against the housing in the stacking direction and the second cover separates a section of the housing adapted to receive filtered fluid from a section of the housing adapted to receive fluid to be filtered.

[0045] A filter element is a component configured to filter fluid as fluid flows across it. A filter element may include two filter elements. The filter element and / or filter elements may have any of the features described above.

[0046] The first cover and the cover backing are placed against the shell in the stacking direction. The first cover and the cover backing are reliably placed on the facing portion of the shell, such that the shell prevents the first cover and the cover backing from moving away from each other.

[0047] The second cover is attached to the cover backing by a return system and returns or biases towards the first cover. Thus, the return system provides a force, such as compressive or tensile force, to maintain the filter elements stacked between the first and second covers in a sealed contact with each other.

[0048] Furthermore, because the second cover separates the area of ​​the housing suitable for receiving filtered fluid (hereinafter referred to as the "clean area") from the area of ​​the housing suitable for receiving fluid to be filtered (hereinafter referred to as the "dirty area"), the fluid pressure on either side of the second cover is not the same due to the pressure drop across the filter element. Therefore, the pressure drop across the second cover pushes the second cover towards the clean area and thus against the filter element, thereby supplementing the recovery system to ensure proper sealing contact of the filter element. Because the pressure drop across the second cover increases with the pressure drop across the filter element, the force caused by the pressure loss across the filter element never exceeds the force caused by the pressure difference across the second cover and the restoring force of the recovery system. Therefore, the reliability of the filter is improved.

[0049] In some embodiments, the cover backing is perforated. That is, the cover backing may include one or more internal openings for fluid flow. This facilitates the flow of the fluid to be filtered toward the second cover, reduces pressure loss across the cover backing, and thus increases pressure on the dirty side of the second cover. Consequently, the reliability of the filter is further improved.

[0050] In some embodiments, at least one of the first and second covers includes a gasket. The gasket may be disposed at the periphery of the cover. This allows for more reliable separation of the different areas.

[0051] In some embodiments, the return system includes at least one return assembly, each of which includes a spring and a stress-applying component for applying stress to the spring. The return system may include multiple return assemblies distributed between the cover backing and the second cover to apply a consistent return force. The spring can be any type of spring, such as a coil spring, a tapered washer, a Belleville washer, a leaf spring, etc. Each assembly may include more than one spring. Furthermore, the stress-applying component can be any component suitable for applying stress to the spring. For example, it includes a nut, a lock nut, a pin, etc. When the stress-applying component actuates, the spring can be prestressed.

[0052] In other embodiments, each return component may include another return element besides the spring, such as an elastic element (like an elastomer) or a magnetic component. Without loss of generality, only the spring will be described below.

[0053] In some embodiments, a spring is mounted between the second cover and the cover backing. The spring may be a compression spring.

[0054] In some embodiments, the filter further includes a sleeve extending from the first cover to the second cover. The sleeve may be concentric with the filter element. The sleeve may be the same as the sleeve described above with reference to the filtration section.

[0055] In some embodiments, the sleeve has a bonded connection to at least one of the first and second caps. This ensures the correct orientation of the first and / or second caps, further contributing to improved reliability.

[0056] In some embodiments, the sleeve has a circumferential groove on the side of the second cover opposite to the filter element. That is, the groove may be located on the dirty side of the second cover. The groove may be located on the same side of the second cover as the cover backing. The groove can facilitate the assembly of the filter, as will be detailed below.

[0057] In some embodiments, at least one of the first and second covers includes a key for mounting one of a plurality of filter elements in a given position relative to the first and second covers. The one of the plurality of filter elements may be an element adjacent to the first cover or adjacent to the second cover. The key is an element that provides a bonding connection between the first and / or second cover and a filter element. Therefore, the key predetermines the relative position of the first and / or second covers (e.g., at an angle) relative to the filter element. Due to the key, the predetermined position between the first and / or second covers can be easily maintained during filter assembly.

[0058] This disclosure further relates to methods for assembling filters, including:

[0059] - Stack multiple filter elements between the first cover and the second cover;

[0060] - Connect the conveyor section to the first cover;

[0061] - The cover backing is attached to the second cover via a return system, wherein the return system is configured to return the second cover toward the first cover;

[0062] - Apply prestress to the recovery system and secure the cover backing to the conveyor section;

[0063] - Install multiple filter elements in the housing such that the first cover rests against the housing in the stacking direction of the filter elements;

[0064] - The cover backing is at least partially removed from the conveying section, such that the cover backing rests against the shell in the stacking direction, and the second cover separates the area of ​​the shell suitable for receiving filtered fluid from the area of ​​the shell suitable for receiving fluid to be filtered.

[0065] The transfer section can be any part configured to bear a load and transfer the load from the first cover to the cover backing, which holds the filter elements stacked between the first and second covers. Thus, by connecting the transfer section to the first cover and securing the cover backing to the transfer section, this connection (secured separately) allows the transfer section to resist the load and keeps the first cover and cover backing resisting the forces exerted by the filter element stack, the second cover, and the return system.

[0066] By prestressing the return system before fastening the cover backing to the conveyor section, the cover backing can be positioned closer to the first cover than it is in the final configuration of the filter. Therefore, multiple filter elements can be mounted in the housing together with the first cover, the second cover, and the cover backing, such that the first cover rests against the housing in the stacking direction of the filter elements, and that after the cover backing is removed from the conveyor section, it rests against the housing in the stacking direction.

[0067] At least partially removing the cover backing means releasing at least one degree of freedom of the cover backing to allow it to rest against the housing. In this configuration, the load between the cover backing and the first cover is transferred through the housing itself and no longer through the transfer section (which can be removed or retained in place, for example, if it has a functional role for the filter). In other words, after fastening, the mechanical load between the first cover and the cover backing is transferred through the transfer section. After disassembly, the mechanical load between the first cover and the cover backing is transferred through the housing. Therefore, it is not necessary to make the transfer section oversized, and its mechanical function may only be temporary.

[0068] The filter obtained from the assembly method may be the filter described above, and may have any of the features described above.

[0069] In some embodiments, the conveying portion is located adjacent to the filter element. In this context, "adjacent" means that the conveying portion does not cross the functional surface of the filter element; however, if the filter element is annular, the conveying portion may be located radially inward (closer to the axis) or radially outward (farther from the axis) of the filter element. In these embodiments, the surface of the filter element can be dedicated to filtration, resulting in improved filtration efficiency. Furthermore, the conveying portion can be more easily removed if desired.

[0070] In some embodiments, the delivery portion includes a sleeve of the filter, which is coaxially mounted to the filter element. The sleeve may be coaxially mounted inside the filter element.

[0071] In some embodiments, securing the cover backing to the conveyor portion includes arranging a stop between the cover backing and the conveyor portion. The stop may be configured to stop the cover backing in the stacking direction, for example, to prevent the cover backing from moving away from the first cover in the stacking direction.

[0072] In some embodiments, the stop is disposed on the side of the cover backing opposite to the second cover. Therefore, during disassembly, the stop is easily accessible and can be easily (partially or completely) removed. This simplifies filter assembly.

[0073] In some embodiments, the load of the return system is transferred via a first portion of the cover backing when it is secured to the transfer section, and via a second portion of the cover backing when it rests against the housing. The first and second portions of the cover backing may be different from each other. The first portion may be for securing the cover backing to the transfer section, while the second portion may be configured to rest against the housing. In these embodiments, the first and second portions can be operated independently, facilitating assembly. Attached Figure Description

[0074] A better understanding of the invention and its advantages will be gained from the following detailed description of embodiments given as non-limiting examples. This description refers to the accompanying drawings, in which:

[0075] - Figure 1 This is a perspective view of the inner surface of the filter member according to an embodiment.

[0076] - Figure 2 yes Figure 1 A perspective view of the outside of the filter component.

[0077] - Figure 3 The stack of filter components according to an embodiment is shown in perspective.

[0078] - Figure 4 The filtering unit according to the embodiment is along Figure 6 The transverse section of plane IV-IV in the middle.

[0079] - Figure 5 The filtering unit according to the embodiment is along Figure 6 The transverse section of plane VV in the middle.

[0080] - Figure 6 This is a longitudinal section of the filter according to an embodiment.

[0081] - Figure 7 yes Figure 6 An exploded perspective view of some components of the filter.

[0082] - Figure 8 yes Figure 6 Detailed view of region VIII.

[0083] - Figure 9 This is a diagram illustrating the steps of a method for assembling a filter according to an embodiment. Detailed Implementation

[0084] Reference Figures 1 to 3 The filter element 10 according to the embodiment is described below. In order to correctly identify the filter elements that are different from each other when described together, the elements associated with the filter element 10 (also referred to as the reference filter element) will receive a standard reference mark, the elements associated with the first identical filter element 10' will receive the same reference mark with an ' (appositive), and the elements associated with the second identical filter element 10" will receive the same reference mark with a (double apostrophe), but they may not be shown or marked in the figures themselves.

[0085] The filter element 10 is annular around the central axis X, defining the axial direction (hereinafter referred to as "axial direction X"). The radial direction is perpendicular to and intersects the central axis. The axial plane is a plane that includes the central axis. The radial plane is a plane perpendicular to the central axis. The circumference is a circle included in the radial plane and having its center on the central axis. The tangential or circumferential direction is the direction tangential to the circumference; it is perpendicular to the central axis but does not intersect it.

[0086] Unless otherwise mentioned or interpreted differently in context, “inner” and “outer” are used with reference to the radial direction, such that the inner element is closer to the central axis X than the outer element.

[0087] Here, the filter element 10 includes an inner edge 24, an outer edge 26, and a filter medium 22 extending between the inner edge 24 and the outer edge 26. The inner edge 24 and the outer edge 26 are annular and may be circular about a central axis X. For example, as shown, the inner edge 24 and the outer edge 26 may be concentric. The inner edge 24 extends primarily in a radial plane. The outer edge 26 extends primarily in a radial plane.

[0088] In this embodiment, the diameter of the outer edge 26 is in the range of approximately 100 mm to approximately 600 mm.

[0089] The filter medium 22 may be a filter screen (hereinafter referred to as "screen 22" without any loss) or any other filter medium. Screen 22 defines the inner surface 20 of the filter member 10 on any side along its axial direction X. Figure 1 (shown in) and outside 21 (in) Figure 2 (As shown in the figure). The characteristics of mesh 22 are adaptable to the fluid to be filtered and the desired impurities to be removed from the fluid.

[0090] The filter member 10 includes ribs 28 at least on its inner surface 20. The ribs 28 extend from the inner edge 24 to the outer edge 26. The ribs 28 may extend in the radial direction. The ribs 28 may be straight. The ribs 28 are distributed circumferentially, for example, regularly, to form sectors on the inner surface 20, such as... Figure 1 As shown in the image.

[0091] Therefore, when the filter element 10 is relative to the first identical filter element 10' (see...) Figure 3 For ease of identification, the filter media 22) are omitted. When their respective inner surfaces 20, 20' face each other, their respective ribs 28, 28' contact each other so that the space defined between the inner surfaces is circumferentially separated. This space is also called the pre-filter chamber.

[0092] In the non-limiting example shown, each filter element is divided into twenty sectors that are regularly spaced circumferentially. Depending on its diameter, a filter element may have fewer or more sectors, for example, due to mechanical limitations.

[0093] The reinforcing rib 29 may also extend between the inner edge 24 and the outer edge 26 (e.g.) Figure 1 As shown in the figure, and / or extending between ribs 28, and / or extending between ribs 28 and at least one of inner edge 24 and outer edge 26. In this embodiment, reinforcing rib 29 is provided between two consecutive ribs 28. As shown, reinforcing rib 29 may extend in a radial direction for ease of manufacture. However, other directions (e.g., circumferential, inclined, etc.) are contemplated.

[0094] On the inner surface, the reinforcing rib 29 may not extend axially as far as the rib 28; that is, it may be at least partially recessed compared to the rib 28, so that the reinforcing rib 29 does not form a separator between sectors. In other words, the distal surface of the reinforcing rib 29 may be closer to the mesh 22 than the distal surface of the rib 28. However, other configurations are possible to ensure that the reinforcing rib 29 does not further define sectors.

[0095] When filter element 10 abuts against the first identical filter element 10' (see...) Figure 3 When the respective inner surfaces 20, 20' of the filter are assembled such that their respective reinforcing ribs 29, 29' can face each other in a direction perpendicular to the filter screen (e.g., axially or substantially axially) to facilitate the flow of the filtered fluid and thus reduce pressure loss.

[0096] As mentioned earlier, the first of the inner edge 24 and the outer edge 26 (here, the inner edge 24) has a passage 30 that communicates with a corresponding sector in the sector on the inner surface 20. The passage 30 may be configured as a notch or cutout in the inner edge 24. The passage 30 may be provided between consecutive radial ribs 28.

[0097] On the other hand, the other edge (here, the outer edge 26) may have no passage on the inner surface 20, for example, such that when the filter member 10 abuts against the first identical filter member 10' (see... Figure 3When assembled such that their respective inner surfaces 20, 20' face each other, their respective outer edges 26, 26' are in sealed contact with each other to prevent flow from the space defined between the inner surfaces (pre-filter chambers) through the outer edges 26.

[0098] Figure 2 Show Figure 1 The outer surface 21 of the filter component 10. For example... Figure 2 As shown, on the outer surface 21, the outer edge 26 has a passage 32. The passage 32 may be configured as a notch or cutout in the outer edge 26. The passage 32 may be provided between consecutive radial ribs 28.

[0099] The radial ribs 28 on the inner surface 20 and the outer surface 21 face each other on opposite sides of the mesh 22. In other words, the ribs 28 on the inner surface 20 and the ribs 28 on the outer surface 21 are axially aligned with each other. In other words, the ribs 28 extend from the inner surface 20 beyond the filter medium and extend to the outer surface 26.

[0100] On the outer surface 21, at least some of the ribs 28 and reinforcing ribs 29 may have protrusions 31 that project axially from the ribs. The protrusions 31 separate the passageways 32 on the outer surface 26 from each other. The protrusions 31 may extend from the outer edge 26 and / or the corresponding ribs 28 or reinforcing ribs 29. Due to the protrusions 31, the ribs 28 may not define sectors on the outer surface 21. Furthermore, the thickness of the ribs 28 on the outer surface 21 is less than the thickness of the ribs 28 on the inner surface 20 to reduce pressure loss on the outer surface 21.

[0101] The filter component 10 can be manufactured by molding around the mesh 22. In other words, the filter component 10 can be manufactured by injection molding or the like, wherein the mesh 22 forms an insert in the mold. The molded portion can be made of metal (e.g., aluminum alloy) or plastic material (especially polymer). Ribs 28, reinforcing ribs 29, and inner edges 24 and outer edges 26 can be coated with an elastomer to prevent leakage between the filter components 10.

[0102] In operation, the fluid to be filtered (e.g., a liquid such as oil or water) enters through the passage 30 of the inner edge 24 of the filter element 10, crosses the filter screen 22 to travel from the inner surface 20 to the outer surface 21, thereby filtering the liquid and flowing out of the filter element 10 through the passage 32 of the outer edge 26. The opposite flow direction is also possible.

[0103] To increase the available filter surface, multiple filter components 10 can be stacked. As previously mentioned, the filter components 10 are assembled relative to each other such that the inner surface 20 faces the inner surface 20' of the adjacent filter component (e.g., the first identical filter component 10'), and the outer surface 21 faces the outer surface 21 of the adjacent filter component (e.g., the second identical filter component 10').

[0104] like Figure 1 As shown, the inner surface 20 includes a first indicator 34 and a second indicator 35 for mating with corresponding second indicators 35' and corresponding first indicators 34' on the inner surface of the first identical filter member 10', respectively. In this embodiment, the first indicator 34 includes a protrusion, such as a male bushing or a boss. In this embodiment, the second indicator 35 includes a recess, such as a female bushing. The shapes of the first indicator 34 and the second indicator 35 are complementary. Figure 3 As shown, the first indicator 34 and the second indicator 35 can be configured such that the filter member 10 and the first identical filter member 10' can be assembled in a single relative position. The first indicator 34 and the second indicator 35 can be opposite in the diametrical direction.

[0105] Furthermore, the outer surface 21 has a key 36 for mates a filter element in a given (and possibly unique) location with respect to a second identical filter element 10". The key 36 may include a protrusion 37 (e.g., a male bushing or boss) and a recess 38 (e.g., a female bushing). Figure 2 As shown, there may be multiple protrusions 37 and / or grooves 38; for simplicity, only one is described. The protrusion 37 is configured to engage in the recess 38” of the second identical filter member 10”. Similarly, as Figure 3 As shown, the recess 38 is configured to receive the protrusion 37” of the second identical filter member 10”. The protrusion 37 and the recess 38 may be opposite in the diametrical direction.

[0106] To prevent the filter components from being misassembled, key 36 may be configured to prevent the outer surface 21 from being assembled to the inner surface 21” of the second identical filter component 10”. For example, in this embodiment, although the first indicator 34 and the second indicator 35 on the inner surface 20 have similar shapes to the key on the outer surface 21, their dimensions prevent them from cooperating with each other. For example, the protrusion of the first indicator 34 may not fit into the recess 38 of the key 36.

[0107] As previously mentioned, key 36 is arranged such that the passage 30” of the second identical filter element 10” is offset relative to the passage 30 of filter element 10. Specifically, as Figure 2 As shown, key 36 is offset relative to the axis of symmetry Y that transforms the first indicator 34 into the second indicator 35. Therefore, when the second identical filter member 10” is rotated inverted to assemble onto the outside 21 of the reference filter member 10, the second identical filter member 10” must be rotated so that key 36 of filter member 10 matches key 36 of the second identical filter member 10”.

[0108] Therefore, the offset can be an angular offset in the circumferential direction. The offset can be an offset in non-integer multiples of sectors. In the illustrated embodiment, the offset is an offset in half a sector. Therefore, from one filter element to another, the passage 30 shifts circumferentially in half a sector.

[0109] like Figure 2 As schematically shown, where axis Z is perpendicular to the central axis X and the axis of symmetry Y, key 36 makes the filter element 10 non-rotationally symmetrical. Therefore, a given position for pairing with a second identical filter element 10” is unique.

[0110] To conserve effective filter surface area, key 36 may face at least one of the ribs, including rib 28 or reinforcing rib 29, in a direction across the filter medium 22 (here, the axial direction X). Similarly, but independently, first indicator 34 and / or second indicator 35 may face at least one of the ribs 28 or reinforcing rib 29 in a direction across the filter medium 22.

[0111] Alternatively, and as shown (see...) Figure 1 The first indicator 34 and / or the second indicator 35 may be oriented toward the key 36 in a direction spanning the filter medium 22.

[0112] For example, Figure 1 As shown for key 36, the bushings forming part or all of the first indicator 34, the second indicator 35, or key 36 may be blind to avoid leakage. In practice, because the bushings may not face each other along the entire stack of filter member 10 (due to offset), a seal cannot be guaranteed simply by having adjacent bushings engage with each other across the entire stack.

[0113] The filter element 10 is assembled with the first identical filter element 10' to produce the filter element 11; in this case, each filter element 10 corresponds to a so-called half-filter element. However, generally, the filter element 11 may be formed differently, for example as a single part or as a component of non-identical parts.

[0114] The properties described above can also be applied to filter elements for a filter unit with backwashing, the filter element being annular and comprising an inner edge (instead of the combination of corresponding inner edges 24, 24'), an outer edge (instead of the combination of corresponding outer edges 26, 26'), and a filter medium extending between the inner and outer edges to define a pre-filter chamber (instead of the space between the facing inner surfaces 20, 20'), the pre-filter chamber being at least circumferentially divided into sectors (possibly by separators other than the corresponding contacting ribs 28, 28'), at least one of the inner and outer edges having a passageway communicating with each of the sectors, wherein the filter element also has a key (possibly similar to key 36) for pairing filter elements in a given position relative to the same filter element, the key being arranged such that the passageway of the same filter element is offset relative to the passageway of that filter element.

[0115] The key may be located on the outside of the pre-filtration chamber to facilitate assembly of filter element 11 with adjacent (possibly identical) filter elements 11'. In the embodiment described above, the outside 21 is located on the outside of the pre-filtration chamber defined between the facing inner surfaces 20, 20'.

[0116] Furthermore, the keys are located at different positions on two opposite sides of the filter element. These different positions can be circumferentially offset relative to each other, so as to cause circumferential offset of other filter elements to be assembled to the filter element. When the filter element comprises two filter members (e.g., as described above), the different positions may be due to the respective outer surfaces being opposite to each other.

[0117] All descriptions of filter components in this disclosure are adapted to filter elements with the necessary modifications. The term "filter portion" refers to filter components and / or filter elements, as appropriate.

[0118] Figure 4 and Figure 5 The backwashing principle of filter element 10 is shown. Therefore, Figure 4 A filter unit 90 is shown, comprising a sleeve 70 and multiple filter sections stacked on top of each other, but only one filter element 10 is visible due to the cross-sectional representation. The sleeve 70 is arranged concentrically with the filter element 10, here adjacent to (e.g., radially inward) the filter element 10. The sleeve 70 has a sealing contact with the filter element 10. The sleeve 70 has an orifice 72 facing a passage 30 toward the filter element 10. Thus, along the longitudinal direction of the sleeve (here, along the axial direction X), the orifice 72 is offset circumferentially, as... Figure 6 As shown in the image.

[0119] To avoid pressure loss, orifice 72 may have approximately the same dimensions as passage 30 (with, for example, a difference of 10% or less). Therefore, the sleeve is not mechanically weakened. In other embodiments, for ease of sleeve manufacturing, orifice 72 may be circular, for example, where the diameter of the circle is the maximum dimension corresponding to passage 30.

[0120] The filter unit 90 also includes a rotary backwash distributor 80 configured to selectively isolate passage 30 to allow backwashing in corresponding sectors. In this embodiment, the distributor 80 is mounted in a central conduit 92 formed inside the sleeve 70 and through which the fluid to be filtered is supplied to passage 30.

[0121] For example, in this embodiment, the dispenser 80 has a gate 82 with a discharge opening 84, and is mounted to rotate (e.g., about a central axis X) such that the discharge opening 84 periodically and selectively communicates with each of the passages 30.

[0122] like Figure 6 As best shown, the discharge opening 84 may extend longitudinally, continuously or discontinuously, over multiple filter sections, such that all passages 30 radially corresponding to the discharge opening 84 (e.g., all aligned passages) simultaneously communicate with the discharge opening 84. For example, the opening 84 may be straight. The opening 84 may extend parallel to the central axis X.

[0123] Figure 4 and Figure 5 The gate 82 is large enough to ensure that the passage 30 is not simultaneously connected to the discharge opening 84 and the central conduit 92.

[0124] Although the illustrated embodiment has a single discharge opening 84, multiple discharge openings 84 can be provided. The discharge openings can be distributed circumferentially, thereby increasing the backwash frequency of a given sector without increasing the speed of the backwash distributor 80. Multiple discharge openings 84 ensure that when a sector is fully backwashed through one of the discharge openings 84, the other discharge openings 84 do not face any path; otherwise, the backwash flow rate would be reduced.

[0125] Due to the offset of the passages 30 in adjacent filter sections, the number of passages 30 communicating with the discharge opening 84 is reduced. Therefore, the backwash flow is distributed between fewer sectors, and the backwash specific flow rate is increased.

[0126] In fact, Figure 5 Is with Figure 4 A similar view, but involving another filter element (here, the adjacent filter element), shows that at the discharge opening 84, it is not... Figure 4 When any passage 30 in the plane comes into contact with the discharge opening 84, Figure 5The path 30 in the plane is connected. The gate will close when the backwash distributor 80 rotates. Figure 5 The passage 30, and the emission opening 84 will be connected to... Figure 4 The filter makes contact with the passage 30. This configuration achieves a filter with continuous backwashing, i.e., at least one sector is backwashed for each location of the backwash distributor 80. Continuous backwashing can be achieved in other ways, for example, by utilizing multiple discharge openings 84. Conversely, by utilizing appropriately sized discharge openings 84, the filter can achieve discontinuous backwashing, i.e., the backwash distributor 80 will have locations where no sector is backwashed.

[0127] In addition, other types of backwash dispensers are included, such as backwash dispensers with fixed columns that communicate with the corresponding passages in passage 30.

[0128] Note that, in addition to being bonded relative to each other, or instead of being bonded relative to each other, the filter portions may be bonded relative to sleeve 70, such that a passage in one of the filter portions is offset relative to a passage in its adjacent filter portion. This includes any type of bonded connection, including those detailed above.

[0129] In the previously mentioned international application WO 2012 / 028824, the filter sections are held together by means of rods extending through the entire stack of filter sections. Now, considering that the filter sections are gradually offset relative to each other, providing the necessary features to allow the rods to be inserted through the entire stack of filter sections would add unnecessary complexity. Instead, another assembly system is proposed.

[0130] Figure 6 A filter 100 is shown, comprising a housing 110 and stacked filter portions, such as filter elements described above, each filter element comprising a pair of filter members 10. The filter elements are axially stacked between a first cover 50 and a second cover 60.

[0131] The first cover 50 rests against the housing 110 in the stacking direction of the filter elements (in this case, in the direction of the central axis X). In particular, the first cover 50 is reliably placed on the shoulder 112 of the housing 110, the shoulder 112 forming a stop that resists axial movement and optional radial movement of the first cover 50.

[0132] The first cover 50 can be a generally circular portion. For example... Figure 6 As shown, the first cover 50 may have a central opening for inserting the sleeve 70. The first cover 50 may extend radially from the sleeve 70 and at least outwardly to the outer edge 26 of the filter member 10. For example, due to the tight gap between them, the first cover 50 and the sleeve 70 may be in sealing contact with each other. A gasket may be provided if necessary.

[0133] The first cover 50 may include a gasket 52. In this embodiment, the annular gasket 52 is received in a peripheral groove of the first cover 50, and then the gasket 52 is compressed between the housing 110 and the first cover 50.

[0134] Similarly, but independently, the second cover 60 can be a generally annular portion. For example... Figure 6 As shown, the second cover 60 may have a central opening for insertion into the sleeve 70. The second cover 60 may extend radially from the sleeve 70 and extend at least outwardly to the outer edge 26 of the filter member 10. For example, due to the tight gap between them, the second cover 60 and the sleeve 70 may be in sealing contact with each other. However, a seal is not required because both the sleeve 70 and the second cover 60 are in the dirty area.

[0135] Therefore, the sleeve 70 extends at least from the first cover 50 to the second cover 60.

[0136] The second cover 60 may include a gasket 62. In this embodiment, the annular gasket 62 is received in a peripheral groove of the second cover 60, and then the gasket 62 is compressed between the housing 110 and the second cover 60.

[0137] To ensure proper alignment of the orifice 72 of the sleeve 70 and the passage 30 of the filter element, the sleeve 70 may have a keyed connection with at least one of the first cover 50 and the second cover 60. For example, as Figure 7 As shown, the first cover 50 may include at least one flat surface 54 (here, two regularly spaced flat surfaces) configured to mate with corresponding flat surfaces 74 on other circular surfaces of the sleeve 70. Although not provided in this embodiment, a connection of the same type or another bonded connection may be provided between the sleeve 70 and the second cover 60. For example, the sleeve 70 may have a partially polygonal cross-section instead of discrete flat surfaces 74.

[0138] Furthermore, at least one of the first cover 50 and the second cover 60 may include a key for mounting one of a plurality of filter elements in a given position relative to said at least one of the first cover 50 and the second cover 60. In this embodiment, Figure 7 The second cover 60 is shown to include a key 64. The key 64 may include a recess configured to engage a key 36 of a filter element, and in particular, engage a protrusion 37. Figure 6 The first cover 50 is shown to similarly, but independently, include a key 56. The key 56 may include a recess configured to engage the key 36 of the filter element, and in particular, an engagement protrusion 37. Thus, the filter 100 presents a bonded connection between the sleeve 70 and the filter element, via at least one of the first cover 50 and the second cover 60, for example, the first cover 50. For ease of manufacture, the keys 56, 64 of the first and second covers may match, but need not be identical to, the key 36 of the filter element.

[0139] like Figure 6 As schematically shown by the arrows, the fluid to be filtered enters the filter through inlet 114 of housing 110, passes through filter 116, and permeates into the central conduit 92 and into the orifice 72 of sleeve 70, which is not isolated by backwash distributor 80. After filtration through the filter section, the filtered fluid is conveyed to the outside of the filter section and drawn off at outlet 118 of housing 110. Simultaneously, backwash distributor 80 is driven to rotate, for example by motor 104. Backwash fluid is discharged from discharge opening 84 and directed to discharge outlet 120 for backwash fluid. If desired, the backwash fluid itself can be purified by another similar filtration unit.

[0140] Therefore, in the housing 110, the second cover 60 separates the region 118a of the housing 110 adapted to receive filtered fluid from the region 114a of the housing adapted to receive fluid to be filtered. Thus, the pressure drop of the fluid between the so-called dirty region 114a and the so-called clean region 118a helps to bias the second cover 60 toward the first cover 50, and thus maintains the filter elements 10 in sealed contact with each other.

[0141] Furthermore, as previously mentioned, the filter 100 also includes a cover backing 40. The cover backing 40 is coupled to a second cover 60 by a return system configured to return the second cover 60 toward the first cover 50. Figure 6 As shown, the cover backing 40 rests against the housing 110 in the stacking direction. In particular, the cover backing 40 is reliably positioned on the shoulder 122 of the housing 110, the shoulder 122 forming a stop that resists axial movement and optional radial movement of the cover backing 40. The shoulder 122 may have a continuous annular shape or may be configured as a plurality of discrete supports.

[0142] The backing 40 can be a generally circular portion. For example... Figure 6 As shown, the cover backing 40 may have a central opening for inserting the sleeve 70. The cover backing 40 may extend radially from the sleeve 70 and extend outward at least to the outer edge 26 of the filter member 10.

[0143] like Figure 7 As shown, the cover backing 40 is perforated. That is, the cover backing 40 has through openings 42 that allow fluid to pass through, which helps to maximize the pressure differential across the second cover 60. The openings 42 may be angled along the circumference of the cover backing 40.

[0144] Now refer to Figures 6 to 9 This describes the method for assembling filter 100.

[0145] As described above, the method includes step S1 of stacking a plurality of filter elements between a first cover 50 and a second cover 60. Each filter element may include a pair of filter members 10, and the connection between adjacent filter elements and / or members may be bonded as detailed above. The first cover 50 and / or the second cover 60 may each face the outside 21 of the filter member 10 closest to it.

[0146] Then, in step S2, the conveying portion is connected to the first cover 50. In this embodiment, the conveying portion is a sleeve 70. In this embodiment, the conveying portion is located next to the filter element, here radially inward and coaxial. However, other arrangements are possible, such as radially outward of the filter element.

[0147] The sleeve 70 (or more generally, the conveying portion) may cooperate with the first cover 50 to at least partially prevent relative displacement of the first cover 50 relative to the sleeve 70. In this embodiment, as Figure 6 As shown, the shoulder 76 of the sleeve 70 serves as a stop for the first cover 50. Furthermore, as detailed above, the flat surface 74 restricts rotation of the first cover 50 relative to the sleeve 70. Therefore, the sleeve 70 is radially and axially connected to the first cover 50.

[0148] Note that step S2 may also be performed before or simultaneously with step S1. Therefore, the conveying part (such as sleeve 70) can be used as a guide to stack the filter elements onto the first cover 50.

[0149] Then, in step S3, the cover backing 40 is coupled to the second cover 60 via the recovery system 44. The recovery system 44 includes at least one (here, multiple) recovery components 45, one of which is in Figure 8 The diagram is shown in more detail below. The return system 44 is configured to return the second cover 60 toward the first cover 50. In this embodiment, the return assembly 45 is located between every two consecutive openings 42.

[0150] Note that opening 42 may be between two consecutive return components 45 (e.g., between two consecutive holes 40a, see below and...). Figure 7 It extends over more than half of the surface of the cover backing 40. The relatively large opening 42 allows contaminants to avoid accumulating on the cover backing 40.

[0151] In this embodiment, the return assembly 45 includes a spring 46 (hereinafter a helical compression spring, but other springs are also possible) and a stress-applying component 47 such as a lock nut (hereinafter “lock nut 47”). The return assembly 45 may also include a pin 48.

[0152] The pin 48 has a pin head 48a that cooperates with a corresponding engagement portion 66 (e.g., a recess) of the second cover 60. Alternatively, in order to distribute the load over a portion larger than the single pin head 48a, a flange 48b is provided under the pin head 48a for resting against the second cover 60.

[0153] Pin 48 includes a pin body 48c, which extends from flange 48b opposite to pin head 48a. Pin body 48c can be inserted into hole 40a of cover backing 40. Pin body 48c may have a non-circular cross section at hole 40a to prevent pin 48 from rotating relative to cover backing 40.

[0154] At the end of the pin body 48c opposite to the flange 48b, the pin 48 may have a locking portion 48d configured to cooperate with the stress-applying member 47. Here, the locking portion 48d includes a threaded portion for cooperating with the lock nut 47. However, other embodiments include, for example, an auxiliary pin configured to be inserted into a transverse hole in the pin 48.

[0155] When the cover backing 40 is attached to the second cover 60, the pin head 48a can be inserted into the engagement portion 66 to prevent rotation between the cover backing 40 and the second cover 60. A spring 46 is mounted around the pin 48, specifically around the pin body 48c, with one end of the spring 46 resting against the flange 48b. The cover backing 40 is mounted against the other end of the spring 46, and a lock nut 47 is screwed onto the locking portion 48d. The lock nut 47 can be screwed on until the spring 46 is compressed as much as possible. As shown, the maximum level of compression can be determined by the enlarged portion of the pin body 48c against which the cover backing 40 rests when the lock nut 47 cannot be screwed on further.

[0156] Therefore, the stress-applying component (locking nut 47) applies stress to the spring 46. In doing so, preferably for each of the return assemblies, the return system 45 is prestressed (step S4).

[0157] Note that the cover backing 40 and the return system 45 can be configured to be pre-assembled with each other as sub-components. Similarly, the cover backing 40 can be pre-attached to the second cover 60; therefore, steps S3 and / or S4 can be performed prior to other steps.

[0158] At step S5, the cover backing 40 is fastened to the conveying portion (i.e., sleeve 70). Specifically, step S5 may include arranging a stop 130 between the cover backing 40 and the conveying portion 70. The stop 130 may be configured as a collar, comprising, for example, two halves constructed to be fastened to each other by bolts. Figure 6 and Figure 7As shown, the stop portion 130 is configured to be arranged in a corresponding groove 78 of the sleeve. The groove 78 may be provided on the side of the second cover 40 opposite to the filter element. In addition, the groove 78 may be located beyond the sleeve position of the cover backing 40, such that the stop portion 130 is arranged on the side of the cover backing 40 opposite to the second cover 60 when installed in the groove 78.

[0159] The stop portion 130 is configured to limit the travel of the cover backing 40 in the axial direction X (in a direction away from the first cover 50 and the second cover 60).

[0160] In another embodiment, the stop 130 may be configured as a resilient collar, possibly a snap-fit ​​collar. In yet another embodiment, the stop 130 may be configured to laterally insert one or more screws or pins into the sleeve 70 and the cover backing 40. The screws or pins may be inserted from the inside of the sleeve 70 so that they can be removed once the filter unit 90 is installed in the housing 110. In these embodiments, the slot 78 is unnecessary. The cover backing 40 may have a thickened portion for inserting the screws or pins. To reduce pressure loss, the thickened portion may taper toward the opening 42.

[0161] At step S6, optionally, the locking nut 47 is loosened, causing the cover backing 40 to bias against the stop 130 due to the expansion of the spring 46, while the second cover 60 biases against the filter element. This prevents the pin 48a from disengaging from the engagement portion 66 should the filter element be rotated inverted or otherwise manipulated for installation into the housing 110. Of course, step S6 is unnecessary if the necessary clearance for disengaging the pin 48a from the engagement portion is greater than the clearance between the cover backing 40 and the stop 130.

[0162] If available Figure 6 As seen in the image, the locking nuts 47 are located in the dirty area 114a so that even if they are separated from the pin 48, they will not interfere with the purified fluid.

[0163] In this state, the load holding the filter elements together is transferred from the first cover 50 to the second cover 60 via the sleeve 70, the stop 130, the cover backing 40, and the return system 45. Note that, as Figure 9 As shown, the load provided by the recovery system 45 is transferred through the first portion of the cover backing 40 (i.e., the radially inner portion of the cover backing 40).

[0164] At step S7, a plurality of filter elements are mounted in the housing 110 together with the cover backing 40, the first cover 50, the second cover 60, the sleeve 70 and the stop portion 130, such that the first cover 50 rests against the housing 110 (e.g., the shoulder 112 as described above) in the stacking direction of the filter elements (i.e., in the axial direction X).

[0165] Then, at step S8, the cover backing 40 is at least partially removed from the transfer section (i.e., sleeve 70). This is done by removing the stop 130. In doing so, under the action of the return system 45, the cover backing is further biased away from the second cover 60 until the cover backing 40 rests against the shell 110 in the stacking direction, as described above.

[0166] In this construction, such as Figure 6 As shown, the second cover 60 separates the clean area 118a from the dirty area 114a.

[0167] Furthermore, due to the removal of the stop 130, no load is transferred through the conveyor section. Instead, the load that holds the filter elements together is transferred from the first cover 50 to the second cover 60 via the housing 110, shoulder 122, cover backing 40, and return system 45. Note that, as Figure 6 As shown, the load provided by the recovery system 45 is transferred through the second part of the cover backing 40 (i.e., the radially outer part of the cover backing 40).

[0168] While this disclosure relates to specific exemplary embodiments, modifications to these examples may be provided without departing from the general scope of the invention as defined by the claims. For example, the steps of the methods described above may be performed in any technically realistic order. Furthermore, the cover backing as described may be used with other types of filter elements (e.g., conventional filter elements). Conversely, the filter elements described herein may be assembled with conventional devices instead of the cover backing, such as with stacked long rods inserted into bushings located radially outward of the outer edge. More generally, the individual features of the different illustrated / mentioned embodiments may be combined in additional embodiments. Therefore, the descriptions and figures should be considered in an illustrative rather than restrictive sense.

Claims

1. A filter element (10) for a filter unit (90) having a backwashing capability, said filter element (10) being annular and comprising an inner edge (24), an outer edge (26), and a filter medium (22) extending between said inner edge (24) and said outer edge (26), said filter element (10) having an inner surface (20) and an outer surface (21) on either side of said filter medium (22), wherein, On the inner surface (20), ribs (28) extending between the inner edge (24) and the outer edge (26) are circumferentially distributed to form sectors, wherein the filter members (10) are adapted to be assembled against a first identical filter member (10') such that their respective inner surfaces (20, 20') define spaces circumferentially separated by the respective ribs (28, 28') of contact on the inner surfaces, wherein the first of the inner edge (24) and the outer edge (26) has a passage (30) communicating with each of the sectors on the inner surface (20), and wherein the outer surface (21) has a key (36) for pairing the filter member (10) in a given position with respect to a second identical filter member (10''), the key (36) being arranged such that the passage (30'') of the second identical filter member (10'') is offset relative to the passage (30) of the filter member (10).

2. The filter element according to claim 1, wherein, The key (36) is configured to prevent the outer surface (21) from being assembled to the inner surface (20'') of the second identical filter member (10'').

3. The filter element according to claim 1 or 2, wherein, The inner surface (20) includes a first indicator (34) and a second indicator (35) for pairing with a corresponding second indicator (35') and a corresponding first indicator (34') of the inner surface (20') of the first identical filter member (10'), respectively, wherein the key (36) is offset relative to the axis of symmetry (Y) that transforms the first indicator (34) into the second indicator (35).

4. The filter element according to claim 1 or 2, wherein, The rib (28) extends beyond the filter medium (22) to the outer surface (21), and the thickness of the rib (28) on the outer surface (21) is less than the thickness of the rib (28) on the inner surface (20).

5. The filter element according to claim 1 or 2, wherein, The key (36) faces at least one of the ribs (28, 29) in a direction across the filter medium.

6. A filter element (11) for a filter unit (90) having backwashing capability, said filter element (11) being assembled from a filter member (10) according to any one of claims 1 to 5 and a first identical filter member (10'), said filter element (11) being annular and comprising inner edges (24, 24'), outer edges (26, 26') and filter media (22, 22') extending between said inner edges (24, 24') and said outer edges (26, 26') to define a pre-filter chamber, said pre-filter chamber being circumferentially divided into sectors, at least one of said inner edges (24, 24') and said outer edges (26, 26') having a passage (30) communicating with each of said sectors, wherein, The filter element (11) also has a key (36) for pairing the filter element (11) in a given position with respect to the same filter element, the key (36) being arranged such that the passage (30) of the same filter element is offset relative to the passage (30'') of the filter element.

7. The filter element according to claim 6, wherein, The key (36) is located outside the pre-filter chamber.

8. The filter element according to claim 6 or 7, wherein, The key (36) is located at different positions on two opposite sides of the filter element (11).

9. A filter section for a filter unit having backwashing, wherein, The filter section is a filter element (10) according to any one of claims 1 to 5.

10. The filtering portion according to claim 9, wherein, The key (36) includes a protrusion (37) and a recess (38), wherein the protrusion (37) is configured to engage in the recess (38'') of the same filter portion.

11. The filtering portion according to claim 9 or 10, wherein, The offset is an offset that is not an integer multiple of the sector.

12. The filtering section according to claim 9 or 10, wherein, The key (36) makes the filter section non-rotationally symmetrical.

13. A filter assembly for a filter unit having a backwash, comprising a sleeve (70) and a plurality of filter sections stacked on top of each other according to any one of claims 9 to 12, wherein, Each filter section has a filter medium (22) and a plurality of passages (30) for guiding fluid to the filter medium (22), the passages (30) being open in separated sectors, wherein the filter section is bonded relative to the sleeve (70) such that a passage (30) of one of the filter sections is offset relative to a passage (30) of an adjacent one of the filter sections.

14. The filter assembly according to claim 13, wherein, The sleeve (70) has an orifice (72) facing the passage (30), and the orifice (72) is offset circumferentially along the longitudinal direction of the sleeve (70).

15. A filter unit (90), said filter unit (90) comprising a plurality of filter elements (10) according to any one of claims 1 to 5, wherein, The filter unit (90) also includes a rotary backwash distributor (80) configured to selectively isolate the passage (30) to allow backwashing in the corresponding sector.

Images