Filter module and method of installing filter module

Abstract

The invention relates to a filter module. The module is substantially cylindrical and extends in a longitudinal direction. The module includes a permeate tube defining a plurality of perforations and a membrane filtration element helically wound around the permeate tube. The membrane filtration element is in fluid communication with at least one of the perforations. The module further includes a wrap around the wound membrane filtration element and a flap for positioning onto and covering at least a portion of an outer surface of the wrap, both the wrap and the flap being made of a fluid permeable polymeric mesh material having ribs extending in a circumferential direction.

Description

Technical Field

[0001] This invention relates to a filter module and a method for installing the filter module into a non-permeable filter housing of a sanitary filtration device. Background Technology

[0002] Hygienic filtration equipment using spiral-wound membranes can be used for reverse osmosis, nanofiltration, ultrafiltration, and microfiltration to efficiently recover, purify, fractionate, or concentrate products in industries such as food, beverage, dairy, biotechnology / bio-based chemicals, and pharmaceuticals.

[0003] The sanitary filtration equipment of the above type is known to use a filter module comprising a membrane filter element spirally wound on a permeate tube. In a typical filtration device, the filter module is housed within a non-permeable filter housing of the sanitary filtration equipment. A pump is used to pump the fluid feed through the filter module housed within the housing.

[0004] Fluid feed enters at one end of the filter housing and travels through the filter module via a wound feed separator positioned parallel to and between the wound membrane layers of the membrane filter element. Separation occurs at the membrane-fluid interface, where a portion of the fluid (called permeate) passes through the membrane layers, while the remaining fluid feed (called residual feed) remains on the opposite side of the membrane as a more concentrated feed. The permeate flows in an inward spiral radial direction until it passes through perforations in the permeate tube for recovery from one or both ends of the permeate tube.

[0005] For use in this type of filtration device housing, the filter module includes a covering that surrounds the membrane filter element to prevent the spirally wound membrane filter element from unwinding and to maintain a uniform diameter of the filter module. However, due to manufacturing tolerances, an annular gap will typically exist between the outer periphery of the module and the inner periphery of the filter housing, in which the fluid feed can flow and bypass the filter module.

[0006] A tight fit between the filter modules is crucial for their proper functioning. A loosely fitted module will allow a significant amount of flow to bypass the filter, resulting in lower flux, faster fouling, lower permeate flow, and higher cleaning costs. Flow bypassing the filter through gaps constitutes a substantial loss and necessitates a pump to remove the unnecessary fluid volume from the filter. Furthermore, filter elements can loosen during operation, leading to membrane buckling or wrinkling, which can damage the membrane and potentially cause leaks.

[0007] Therefore, the object of the present invention is to provide a technology that allows the filter module to fit tightly into the housing regardless of manufacturing tolerances.

[0008] US 2013 / 0161258 A1 relates to a brine seal for a helically wound membrane element. The brine seal has an elongated body with flexible wings. The brine seal wraps around the helical membrane element, with a space between each turn of the brine seal.

[0009] JP 2011 / 092905A relates to a membrane with protrusions.

[0010] US 8668828 relates to a helically wound membrane tube having a thin tubular shell with a textured outer surface to allow controlled bypass flow of liquid feed between the interior of the pressure vessel and the textured outer surface of the shell.

[0011] US 5985146 relates to a fluid separation device having a rigid, non-porous housing and a helically wound membrane filter element positioned within the rigid, non-porous housing. Threaded grooves surround the circumference of the outer surface of the housing and extend along its length.

[0012] US 4064052 relates to a spirally wound membrane having a lip seal between a module and a receiving tube.

[0013] US 2009 / 0200237 A1 relates to a filter medium having a flow control strip at one end that circumferentially surrounds the medium. The strip is preferably an open mesh material that cooperates with the overlapping portion of the open mesh surrounding the filter medium. The strip creates a compressible region that restricts bypass flow while allowing for easy installation and removal of the membrane module.

[0014] US 4839037 relates to a spirally wound filter cartridge comprising a centrally located tube and a sheet of filter material spirally wound around the tube.

[0015] US 5128037 relates to a helically wound filter cartridge having an end plate for controlling fluid flow in the space between the outer cartridge and the housing.

[0016] US 4902417 relates to a spirally wound membrane tube having a feed layer having a plurality of parallel ribs.

[0017] US 4548714 relates to a membrane tube for insertion into a pressure vessel. The tube has a porous mesh material having an extension of sufficient length to surround the circumference of the tube when it is positioned inside the vessel.

[0018] US 5073263 relates to an ultrafiltration module comprising a permeate collection tube, one or more membrane leaves wound around the tube, an outer wrapping screen of the outer wrapping of the leaves, and a bypass screen, also of an open mesh construction, wrapped around the outer wrapping.

[0019] US 3063888 relates to a filter tube having strips of porous material.

[0020] US 5460720 relates to a fluid separation apparatus that utilizes a tubular or flat sheet membrane material, constrained on the membrane side of the sheet by a porous feed spacer material sheet.

[0021] WO 2022 / 187472 A1 relates to a bypass control sleeve having circumferential protrusions along its outer surface. Summary of the Invention

[0022] According to a first aspect of the invention, the above-mentioned objective is achieved by a filter module for filtering a fluid feed into a permeate portion and a residual portion, the module being substantially cylindrical and extending longitudinally between a first end and a second end, the first end and the second end being substantially circular, the module comprising: The permeation tube, which essentially extends between a first end and a second end, defines multiple perforations. A membrane filter element, which extends substantially between a first end and a second end and is helically wound around a permeate tube, is in fluid communication with at least one perforation. An encapsulation, which surrounds and extends substantially between a first end and a second end of a wound membrane filter element, defines an outer surface that defines a circumferential direction substantially perpendicular to the longitudinal direction. A flap, used to be positioned on and cover at least a portion of the outer surface of a package, both the package and the flap being made of a fluid-permeable polymer mesh material having ribs extending in the circumferential direction.

[0023] Both the vanes and the wrapping are made of a fluid-permeable polymer mesh material to allow feed fluid to pass through. The wrapping essentially covers the entire cylindrical surface of the wound membrane filter element, but not the circular ends. It serves as a single or multiple-layer sleeve or sheath for a tight fit, and may include multiple layers. Both the vanes and the wrapping have ribs extending in the circumferential direction to increase flow resistance to the fluid feed flowing in the longitudinal direction. The vanes are provided to compensate for manufacturing tolerances and can be cut to a suitable circumferential length so that the outer periphery of the filter module matches the inner periphery of the filter housing. In this way, a tight fit is achieved between the filter module and the filter housing.

[0024] The fins are essentially loosely fitted to the outer surface of the package to allow them to adapt to the internal space of the filter housing. The fins are provided with ribs to cooperate with the ribs of the package to accommodate the difference between the outer periphery of the filter module and the inner diameter of the housing, and to hold the fins in place without wrinkling or buckling during insertion of the module into the housing.

[0025] According to another embodiment of the first aspect, the wing tapers longitudinally from the second end to the first end.

[0026] By using tapered vanes, the filter module can be installed into the housing of the filter device very quickly and efficiently. The tapered vanes allow the circumference of the filter module to increase longitudinally from the first end to the second end. A direct indication of the width of the vanes that need to be cut off is given by inserting the first end of the filter module into the opening of the filter housing and sliding the filter module into the interior space of the filter housing until the circumference of the filter module exceeds the circumference of the opening. The filter module is thus inserted into the filter housing until it stops, while the remaining portion of the filter module remains outside the housing.

[0027] By reducing the circumference of the remaining portion of the spiral filter module by cutting the fins at the point where the fins meet the opening, it becomes possible to insert the remaining portion of the spiral filter module into the housing and achieve a tight fit without any trial and error and without the risk of cutting off too many fins.

[0028] According to another embodiment of the first aspect, the wing is defined as a first edge extending in a circumferential direction at a first end, a second edge extending in a circumferential direction at a second end and longer than the first edge, and a third edge extending at an angle relative to the longitudinal direction between the first edge and the second edge.

[0029] Preferably, one longitudinal edge of the wing forms an angle with respect to the longitudinal direction of the filter module to provide a tapering of the wing.

[0030] According to another embodiment of the first aspect, the wing defines a fourth edge that extends between the first and second edges relative to the third edge and defines an angle relative to the longitudinal direction.

[0031] The two longitudinal edges of the wing can form an angle relative to the longitudinal direction of the filter module to allow the wing to be cut at two locations.

[0032] According to another embodiment of the first aspect, the ribs of the package define a first spacing between them, and the ribs of the wing define a second spacing between them, the first spacing being different from the second spacing.

[0033] In this way, some ribs on the fins overlap with some ribs on the enclosure, providing some flexibility between the fins and the enclosure. This allows the filter module to adapt to manufacturing tolerances and helps achieve a tight fit between the housing and the filter module.

[0034] According to another embodiment of the first aspect, the winglets are fixed to the package by, for example, adhesive or welding.

[0035] The flaps can be provided loosely and applied to the outer surface of the wrapping just before installation. Alternatively, they can be secured to the outer surface of the wrapping to ensure proper installation and prevent the flaps from slipping, buckling, or wrinkling during installation. The flaps can be secured by, for example, gluing or welding (such as spot welding). They can be secured in one or more locations. They can be secured along one or more lateral or longitudinal directions. They can be secured at one or more edges or the center.

[0036] According to another embodiment of the first aspect, the ribs of the package and the ribs of the wing face each other, or alternatively, the ribs of the package and the ribs of the wing face the same direction.

[0037] In this way, any longitudinal movement of the vane relative to the outer surface of the enclosure is prevented. This prevents the vane from slipping, buckling, or wrinkling during installation. Additionally, some ribs on the vane interact with some ribs on the enclosure, providing some flexibility between the vane and the enclosure. This allows the filter module to accommodate manufacturing tolerances and facilitates a tight fit between the housing and the filter module. Alternatively, the ribs on the enclosure and the vane face the same direction. This increases turbulence in the gap and thus reduces crossflow. Preferably, in the latter case, the enclosure and the vane are fixed to prevent slippage.

[0038] According to another embodiment of the first aspect, the winglet defines greater flexibility and / or greater elasticity than the wrapping.

[0039] This allows the filter module to be adapted to manufacturing tolerances and helps to achieve a tight fit between the housing and the filter module.

[0040] According to another embodiment of the first aspect, the membrane filter element includes one or more permeate transfer plates, one or more membrane sheets, and one or more feed separators. The permeate transfer plates allow permeate to flow to perforations or permeate tubes after passing through the membrane sheets. The feed separators allow residual permeate to flow through the filter module.

[0041] According to an embodiment of the first aspect, the filter module according to any of the preceding claims, wherein the fins extend less than one circumferential turn along the outer surface, preferably between 20% and 80% of one circumferential turn along the outer surface, more preferably between 30% and 70% of one circumferential turn along the outer surface.

[0042] The flaps do not necessarily have to cover the entire outer surface of the package. Installation will be easier if the flaps only cover a portion of the outer surface.

[0043] According to another embodiment of the first aspect, the length of the winglet in the longitudinal direction is substantially equal to or less than the distance between the first end and the second end, preferably between 20% and 80% of the distance between the first end and the second end, more preferably between 30% and 70% of the distance between the first end and the second end.

[0044] Preferably, the length of the wing in the longitudinal direction is substantially equal to the length of the package.

[0045] According to a second aspect of the invention, the above objective is achieved by a method of mounting a filter module into a non-permeable filter housing, the filter housing defining an opening and an internal space accessible through the opening, the opening defining a first periphery, the method comprising: Provides a filtering module according to the first aspect, the filtering module defining the second perimeter, Insert the first end of the spiral filter module into the opening of the housing, and Slide the spiral filter module into the interior space of the housing until the second perimeter exceeds the first perimeter, thus leaving the remaining part of the filter module outside the housing. The second periphery of the remaining portion of the spiral filter module is reduced by cutting the fins at the point where the fins meet the opening. Insert the remaining part of the spiral filter module into the housing.

[0046] Preferably, the above methods are used in conjunction with any of the embodiments of the first aspect.

[0047] According to another embodiment of the second aspect, the winglet is cut either circumferentially or longitudinally. Cutting circumferentially may be easier because it eliminates the need to cut any of the ribs. Cutting circumferentially may be more efficient because it leaves a larger effective area of ​​the winglet.

[0048] According to a third aspect of the invention, the above objective is achieved by a method of mounting a filter module into a non-permeable filter housing, the filter housing defining an opening and an internal space accessible through the opening, the opening defining a first periphery, the method comprising: Provides a filtering module according to the first aspect, the filtering module defining the second perimeter, Insert the first end of the spiral filter module into the opening of the housing, and Slide the spiral filter module into the internal space of the housing. This reduces the second perimeter to match the first perimeter by causing interference between the ribs of the package and the ribs of the wing.

[0049] Preferably, the above methods are used in conjunction with any of the embodiments of the first aspect. Attached Figure Description

[0050] Figure 1A This is a view of the permeate tubes and membrane filter elements before they are wound up.

[0051] Figure 1B This is a view of the permeate tube and part of the spiral membrane filter element.

[0052] Figure 1C This is a view of the wrapping material surrounding the wound membrane filter element.

[0053] Figure 1D This is a view of the filter module inserted into the filter housing.

[0054] Figure 2 This is a view of the filter module installed in the filter housing.

[0055] Figure 3A It is a view that includes the filter module for tapered fins and wrapping.

[0056] Figure 3B This is a view of a filter module with tapered flaps positioned on the package.

[0057] Figure 3C This is a view of the filter module inserted into the filter housing.

[0058] Figure 3D This is a view of the filter module partially inserted into the filter housing.

[0059] Figure 3E This is a view of the longitudinal section of the wing.

[0060] Figure 3F This is a view of the circumferential cut of the airfoil.

[0061] Figure 3G This is a view of the filter module fully inserted into the filter housing.

[0062] Figure 3H This is a view of the filter housing closed.

[0063] Figure 4A It is a view that includes individual fins and a filter module.

[0064] Figure 4B It is a view that includes a filter module with individual flaps positioned on the package.

[0065] Figure 5A This is a view including a filtering module with flexible flaps positioned on the package.

[0066] Figure 5B This is a view including a filtering module with flexible flaps positioned on the package.

[0067] Figure 5C This is a view of a filter module including flexible blades inserted into the filter housing. Detailed Implementation

[0068] Figure 1A This is a side view of the permeate tube 10 and a plurality of unwound membrane filter elements 12. Each membrane filter element 12 includes a permeate transfer plate 14, a membrane sheet 16, and a feed separator 18. The permeate tube 10 includes a plurality of perforations 20 for permeate (not shown). A fluid feed (not shown) is intended to flow through the feed separator 18, allowing the membrane sheet 16 to separate the fluid feed (not shown) into permeate (not shown) flowing through the membrane sheet 16 and residual material remaining in the feed separator 18 and flowing through the membrane filter element 12. The permeate (not shown) flows into the permeate tube 10 via the perforations 20.

[0069] Figure 1B This is a side view of the membrane filter element 12, which includes a permeate transfer plate 14, a membrane sheet 16, and a feed separator 18 that partially spiral around the permeate tube 10 as indicated by the arrows. This forms a generally cylindrical assembly including the membrane filter element 12 and the permeate tube 10.

[0070] Figure 1C This is a perspective view of a filter module 26, which includes a wrapping 22 surrounding a wound membrane filter element 12, thus forming a generally cylindrical filter module 26. The wrapping 22 is made of a fluid-permeable polymer mesh material and has ribs 24 extending in the circumferential direction. The wrapping 22 is fluid-permeable to allow fluid feed to flow through. The wrapping 22 may be formed in one or more layers, forming a sleeve or sheath surrounding the membrane filter element 12. The purpose of the wrapping 22 is to prevent the membrane filter element 12 from unfolding and to hold the membrane filter element 12 in place during operation to prevent buckling or wrinkling. The circumferentially extending ribs 24 reinforce the wrapping 22 and prevent slippage between the wrapping 22 and the membrane filter element 12. The ribs 24 also increase the flow resistance of the feed exiting the membrane filter element 12. The wrapping 22 is fixed to itself by welding or gluing.

[0071] Figure 1D This is a perspective view of the filter module 26 inserted into the filter housing 28. The substantially cylindrical filter module 26 is inserted into the non-permeable filter housing 28 through an opening 28a. The opening 28a is circular and substantially corresponds to the circumference of the filter module 26. The filter housing 28 has an internal space 28b, which substantially corresponds to the external shape of the filter module 26. The housing 28 has a feed inlet 30 and a feed outlet 32 ​​located at opposite ends of the housing 28, and a permeate outlet 34 located centrally at one end of the housing 28. The opening 28a of the housing 28 is hermetically sealed by a cover 36.

[0072] Figure 2 This is a cross-sectional view of the filter module 26 installed in the filter housing 28. Fluid feed enters the housing 28 via the feed inlet 30 as indicated by the arrows and continues through the filter module 26 as previously described. Permeate flows out of the housing 28 through the feed outlet 32. Permeate flows out through a centrally located permeate tube 10, which is in fluid communication with the permeate outlet 34. To account for manufacturing tolerances of the filter module 26 and the housing 28, an annular gap 38 exists between the filter module 26 and the housing 28 within the internal space 28b of the housing 28. The gap 38 poses a problem because flow bypassing the filter module 26 through the gap 38 would constitute a substantial loss and would require pumping an unnecessary amount of fluid feed (not shown) through the filter module 26. Furthermore, the membrane filter element 12 may loosen during operation, which could lead to buckling or wrinkling of the membrane filter element 12, potentially causing damage and leakage.

[0073] Figure 3A This is a perspective view of a filter module 26 including a tapered vane 40. The tapered vane 40 defines a first edge 40a extending circumferentially at a first end of the filter module 26, a second edge 40b extending circumferentially at a second end of the filter module 26 and longer than the first edge 40a, a third edge 40c extending longitudinally along a straight line between the first edge 40a and the second edge 40b, and a fourth edge 40d extending between the first edge 40a and the second edge 40b opposite to the third edge 40c and defining an angle relative to the longitudinal direction. The vane 40 is made of a fluid-permeable polymer mesh material, similar to a wrapper 22, and has ribs 42 extending circumferentially.

[0074] Figure 3B This is a perspective view of a filter module 26 having tapered flaps 40 positioned on a package 22. The flaps 40 cover the package 22 less than one circumference. The flaps 40 are provided as a separate part or can be fixed (i.e., welded or glued) to the package 22. The tapering of the flaps 40 will cause the periphery of the filter module 26 to increase longitudinally from the first edge 40a to the second edge 40b.

[0075] Figure 3C This is a perspective view of a filter module 26, including a vane 40, inserted into the internal space 28b of a filter housing 28 via an opening 28'. The upper enlarged portion shows the ribs 42 of the vane 40 and the ribs 24 of the enclosure 22 facing the same direction, the vane 40 and the enclosure 22 being fastened together by spot welding 44. The lower enlarged portion shows the ribs 42 of the vane 40 and the ribs 24 of the enclosure 22 facing each other and interlocking to prevent slippage between the vane 40 and the enclosure 22 when the filter module 26 is inserted into the filter housing 28.

[0076] Figure 3D This is a perspective view of the filter module 26 partially inserted into the filter housing 28. As the periphery of the filter module 26 increases longitudinally, the gap between the opening 28a and the filter module 26 decreases as the filter module 26 is inserted more into the housing 28. An indication of the width of the fin 30 that needs to be cut off is given by sliding the filter module 26 into the interior space 28b of the housing 28 until the filter module 26 stops due to its inability to fit into the housing 28. This indication is the position where the third edge 40c of the opening 28a and the fin 40 intersects when the periphery of the filter module 26 exceeds the periphery of the opening 28a.

[0077] Figure 3E This is a perspective view of the longitudinally cut fin 40 at position 46. By reducing the circumference of the remaining portion of the filter module 26 by cutting the fin 40 at the location where the third edge 40c of the fin 40 meets the opening 28a, it is possible to insert the remaining portion of the filter module 26 into the housing 28 and achieve a tight fit without any use of trial and error and without the risk of cutting off too much of the fin 40.

[0078] Figure 3F This is a perspective view of a circumferential cut made to the wing 40 at position 48. Cutting the wing 40 circumferentially removes more of the wing 40 and is therefore less efficient than cutting longitudinally; however, by cutting the wing 40 circumferentially, it is not necessary to cut through the rib 42, which allows for easier cutting. It is even possible to tear the wing 40 by hand without using any tools such as a knife (not shown) or scissors (not shown).

[0079] Figure 3G This is a perspective view of the filter module 26 fully inserted into the filter housing 28. For most of the filter module 26, gaps will be essentially eliminated, reducing many of the aforementioned problems.

[0080] Figure 3H This is a perspective view of the filter housing 28 closed by applying cover 36. The filter housing 28 is now ready for operation. The filter module 26 is removed by removing cover 36 and pulling out the filter module 26.

[0081] Figure 4AThis is a perspective view of an alternative embodiment of the filter module 26', which is similar to the previous embodiment except that it includes a variant of the tapered fin 40'. The fin 40' defines a first edge 40'a extending circumferentially at a first end of the filter module 26', a second edge 40'b extending circumferentially at a second end of the filter module 26' and longer than the first edge 40'a, a third edge 40'c extending between the first edge 40'a and the second edge 40'b and defining an angle relative to the longitudinal direction of the filter module 26', and a fourth edge 40'd extending between the first edge 40'a and the second edge 40'b opposite to the third edge 40'c and defining an angle relative to the longitudinal direction. The fin 40' is made of a fluid-permeable polymer mesh material, similar to the wrapper 22', and has ribs extending circumferentially.

[0082] Figure 4B This is a perspective view of a filter module 26' having tapered flaps 40' positioned on a package 22'. The flaps 40' cover less than one circumference around the package 22'. The flaps 40' are provided as a separate part, or may be fixed (e.g., welded or glued) to the package 22'. Therefore, the periphery of the filter module 26' will increase in the longitudinal direction. The installation of the filter module 26' is similar to the previous embodiment, except that the flaps 40' will be cut twice, once at the third edge 40'c and once at the fourth edge 40'd.

[0083] Figure 5A This is a perspective view of a filter module 26'' of another alternative embodiment, similar to the previous embodiment, except that the fins 40'' have straight edges, are flexible / elastic, and have ribs 42'' that define a different spacing between them than the ribs 24'' of the wrapper 22''. The fins 40'' cover the wrapper 22'' less than one circumference.

[0084] Figure 5B This is a perspective view of a filter module 26'' including a flexible flap 40'' positioned on the package 22''. The flap 40'' is preferably attached to the package 22'', for example by welding or gluing. As seen in the close-up view, the ribs of the flap 40'' face the ribs of the package 22''.

[0085] Figure 5CThis is a perspective view of the filter module 26'', including the fins 40'' inserted into the filter housing 28. The fins 40'' are adaptable to various peripheries of the interior space of the housing 28 for a tight fit. This is achieved through varying spacing between the ribs 42'' of the fins 40'' and the ribs 24'' of the enclosure 22'', allowing some ribs 42'' of the fins 40'' to overlap / interfere with some ribs 24'' of the enclosure 22'', providing additional flexibility between the fins 40'' and the enclosure 22''. This allows the filter module 26'' to accommodate manufacturing tolerances of both the filter housing 28 and the filter module 26'', and facilitates a tight fit between the housing 28 and the filter module 26'', while also allowing for a very simple installation procedure, as no cutting or other adjustments to the fins 40'' are required during installation.

Claims

1. A filter module for filtering a fluid feed into a permeate portion and a residual portion, the module being substantially cylindrical and extending longitudinally between a first end and a second end, the first end and the second end being substantially circular, the module comprising: A permeation tube, which extends substantially between the first end and the second end, defines a plurality of perforations. A membrane filter element, which extends substantially between the first end and the second end and is helically wound around the permeate tube, the membrane filter element being in fluid communication with at least one of the perforations. An encapsulation, which surrounds a wound membrane filter element and extends substantially between the first end and the second end, defines an outer surface that defines a circumferential direction substantially perpendicular to the longitudinal direction. A flap for positioning onto and covering at least a portion of the outer surface of the package, both the package and the flap being made of a fluid-permeable polymer mesh material having ribs extending along the circumferential direction, wherein the flap tapers from the second end to the first end along the longitudinal direction.

2. The filtering module according to claim 1, wherein, The ribs of the package define a first spacing between them, and the ribs of the wing define a second spacing between them, the first spacing being different from the second spacing.

3. The filtering module according to any one of the preceding claims, wherein, The ribs of the package and the ribs of the wing face each other, or alternatively, the ribs of the package and the ribs of the wing face the same direction.

4. A filter module for filtering a fluid feed into a permeate portion and a residual portion, the module being substantially cylindrical and extending longitudinally between a first end and a second end, the first end and the second end being substantially circular, the module comprising: A permeation tube, which extends substantially between the first end and the second end, defines a plurality of perforations. A membrane filter element, which extends substantially between the first end and the second end and is helically wound around the permeate tube, the membrane filter element being in fluid communication with at least one of the perforations. An encapsulation, which surrounds a wound membrane filter element and extends substantially between the first end and the second end, defines an outer surface that defines a circumferential direction substantially perpendicular to the longitudinal direction. A flap for positioning onto and covering at least a portion of the outer surface of the package, both the package and the flap being made of a fluid-permeable polymer mesh material having ribs extending along the circumferential direction, wherein the ribs of the package define a first spacing between them and the ribs of the flap define a second spacing between them, the first spacing being different from the second spacing, the ribs of the package and the ribs of the flap facing each other.

5. The filtering module according to claim 4, wherein, The wing tapers from the second end to the first end along the longitudinal direction.

6. The filtering module according to any one of the preceding claims, wherein, The wing is defined by a first edge extending in the circumferential direction at the first end, a second edge extending in the circumferential direction at the second end and longer than the first edge, and a third edge extending at an angle relative to the longitudinal direction between the first edge and the second edge.

7. The spiral filter module according to claim 6, wherein, The wing defines a fourth edge that extends between the first and second edges opposite to the third edge and defines an angle relative to the longitudinal direction.

8. The filtering module according to any one of the preceding claims, wherein, The flaps are fixed to the package by, for example, adhesive or welding.

9. The filtering module according to any one of the preceding claims, wherein, The winglet defines a higher degree of flexibility than the package.

10. The filtering module according to any one of the preceding claims, wherein, The winglet defines a higher degree of elasticity than the wrapping material.

11. The filtering module according to any one of the preceding claims, wherein, The membrane filtration element includes one or more permeate transfer plates, one or more membrane sheets, and one or more feed separators.

12. The filtering module according to any one of the preceding claims, wherein, The wing extends along the outer surface in the circumferential direction for less than one circle, preferably between 20% and 80% of one circle along the outer surface in the circumferential direction, and more preferably between 30% and 70% of one circle along the outer surface in the circumferential direction.

13. The filtering module according to any one of the preceding claims, wherein, The length of the winglet in the longitudinal direction is equal to or less than the distance between the first end and the second end, preferably between 20% and 80% of the distance between the first end and the second end, and more preferably between 30% and 70% of the distance between the first end and the second end.

14. A method of mounting a filter module into a non-permeable filter housing, the filter housing defining an opening and an internal space accessible through the opening, the opening defining a first periphery, the method comprising: A filtering module is provided according to any one of the preceding claims, the filtering module defining a second perimeter. Insert the first end of the spiral filter module into the opening of the housing, and The spiral filter module is slid into the interior space of the housing until the second periphery exceeds the first periphery, thereby leaving the remaining part of the filter module outside the housing. The second periphery of the remaining portion of the spiral filter module is reduced by cutting the wing at the location where the wing meets the opening. Insert the remaining portion of the spiral filter module into the housing.

15. The method according to claim 14, wherein, The wing is cut along the circumferential direction.

16. The method of claim 14, wherein, The wing is cut along the longitudinal direction.

17. A method of mounting a filter module into a non-permeable filter housing, the filter housing defining an opening and an internal space accessible through the opening, the opening defining a first periphery, the method comprising: A filtering module is provided according to any one of the preceding claims, the filtering module defining a second perimeter. Insert the first end of the spiral filter module into the opening of the housing, and The spiral filter module is slid into the internal space of the housing. This reduces the second perimeter to match the first perimeter by causing interference between the ribs of the package and the ribs of the wing.

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