Filter unit having filter element and screening device

Abstract

There is provided herein a filter unit (10) comprising a filter element (2) and a screening device (21). The screening device (21) comprises a screen body (22), an aperture (23) positioned substantially in the center of the screening device (21), an outer ring (25) in the outer periphery of the screening device (21), and the screen body (22) between the aperture and the outer ring. Further provided is a filtration system (1) comprising a container (3), a feed port (4), a permeate outlet (5), optionally a retentate outlet (6), and at least filtration units (10) within the container (3), and for at least one set of filtration units, a screening device (21) is positioned in front of the filtration elements (2) in the direction of feed flow.

Description

Technical Field

[0001] The present disclosure provides a filter element and a filtration system having an integrated pre-filter. More specifically, the filtration unit includes a filter element and a screening device. The screening device includes a screen body and an orifice substantially positioned at the center of the screening device, an outer ring in the outer periphery of the screening device, and the screen body between the orifice and the outer ring. The outer ring includes an inner surface connected to the housing. Background Art

[0002] Several patents, patent applications, and publications are cited in this specification to more fully describe the state of the art to which the present invention pertains. The entire disclosure of each of these patents, patent applications, and publications is hereby incorporated by reference.

[0003] Filtration media (such as membranes, e.g., reverse osmosis (RO) membranes, nanofiltration (NF) membranes, ultrafiltration (UF) membranes, microfiltration (MF) membranes, electrodialysis (ED) membranes, distillation membranes, degassing membranes, and ion exchange membranes) are commonly and effectively used in fluid treatment. By applying a driving force (in most cases, pressure) to one surface of the membrane, the membrane is capable of separating the feed fluid into a permeate flow that passes through the membrane and a retentate flow that contains the filtration material. The most important application is water purification by treating process streams such as industrial waste, seawater, groundwater, sewage, and effluents from sewage treatment facilities. Other industrial uses include purifying and / or concentrating dairy products, fruit juices, and other beverages; enzyme recovery; and dialysis.

[0004] MF membranes commonly have pore sizes between 0.1 micrometers and several micrometers, which can be used to remove large microbial substances, such as some bacteria. UF membranes typically have pore sizes between 0.1 micrometers and 0.01 micrometers, which are small enough to separate a wider range of microorganisms (including viruses and other pathogens), as well as macromolecules, nanoparticles, proteins, biological cell debris, etc. NF membranes generally have pore sizes between 0.001 micrometers and 0.01 micrometers to effectively remove divalent ions, most organic molecules, almost all viruses, and a range of salts. RO membranes typically have pore sizes between 0.0001 micrometers and 0.001 micrometers, which are the finest membranes available industrially for removing all organic molecules, viruses, and most minerals.

[0005] Membranes are vulnerable to fouling and damage by larger particles. Therefore, before feeding into the filtration system, a coarse screen and / or a fine screen are used to treat the feed fluid to remove large particles that may damage or block the membranes in the filtration system. Generally, for UF systems and MF systems, the pretreatment includes a self-cleaning filter with a screening size of 50 micrometers to 400 micrometers, more preferably 100 micrometers to 300 micrometers. Typically, UF membranes and / or MF membranes are used as pretreatment for finer RO membranes and NF membranes.

[0006] Since the pre-filter used in the pretreatment is for removing larger particles, it is prone to clogging and requires frequent cleaning, such as backwashing and / or chemical cleaning, to restore the original flux. UF membranes and MF membranes are used to remove relatively large particles; these membranes also need to be cleaned regularly. The normal cleaning processes for UF membranes and MF membranes include, but are not limited to, backwashing, air scouring, chemically enhanced backwashing (CEB), and in-situ cleaning (CIP). During the cleaning process of UF membranes and MF membranes, the most commonly applied is backwashing, which is usually cycled every 20 minutes to 60 minutes based on the feed conditions. For RO membranes and NF membranes, which are usually composite membranes, CIP is an effective cleaning process. In industrial and wastewater treatment settings, pretreatment is performed using a separate pre-filter system upstream of the filtration system, i.e., the pretreatment filter is usually separated from the downstream filtration system as a separate device. In these cases, there are usually separate and time-consuming cleaning processes for the pretreatment filter and the filtration system.

[0007] To reduce the footprint of the system, the amount of piping, and the number of connectors, multiple filter elements can be employed within a pressure vessel to form a multi-element filtration system. In these designs, the multi-element filtration system has a single set of feed ports, permeate outlets, and retentate outlets, rather than a set for each element. Multi-element filtration systems are widely used in water treatment facilities to purify water and also serve as reactors in various chemical manufacturing processes. The most commonly used commercial RO systems are multi-element filtration systems that include multiple RO elements placed horizontally in series within a pressure vessel ( Figure 1 a). There are also horizontal systems with RO elements placed in parallel ( Figure 1 b). Commercial multi-element UF or MF systems include horizontal elements in series ( Figure 1 a) and vertical elements in parallel ( Figure 1 c). The vertical elements can also be placed in series ( Figure 1 d). Generally, horizontal multi-element UF or MF systems use inside-out membranes, and vertical multi-element UF or MF systems use outside-in membranes.

[0008] Attempts have been made to integrate the pre-filter with the filter element or system. Examples of integrating the pre-filter into the element housing can be seen in JP03193122, JP04338221, and CN218249518, and examples of inserting the pre-filter into the element from the side of the housing can be seen in CN216358934. Examples of integrating screening within a vertical multi-element system can also be seen in KR10-1303993, and examples of integrating a cylindrical pre-filter from below above a vertically arranged filter element can be seen in WO 2016042179.

[0009] However, there is still a need to integrate a pre-filter with an element that is easy to handle, transport, and install into a multi-component system. In particular, for UF or MF elements that process raw liquids with relatively high turbidity, it is necessary to integrate a pre-filter with an element that can be easily handled, transported, and installed into a multi-component system. Additionally, there is a need to integrate the pre-filter with the filtration element or system in a simple and effective manner, which is crucial for installation and cost control. SUMMARY OF THE INVENTION

[0010] Accordingly, there is provided herein a filtration unit comprising:

[0011] a filtration element having at least one filtration membrane with a first surface in contact with the feed and a second surface in contact with the permeate, at least one end of the filtration element including an opening to introduce the feed onto the first surface of the filtration membrane; and a central conduit surrounded by the filtration membrane to collect the permeate; and

[0012] a screening device preferably connected to the end of the filtration element including one or more openings for introducing the feed onto the first surface of the filtration membrane, the screening device including an orifice substantially positioned at the center of the screening device, an outer ring in the outer periphery of the screening device, and a screen body between the orifice and the outer ring.

[0013] The filtration membrane may be surrounded by a housing. The outer ring may include an inner surface connected to the inner surface of the housing. The outer ring may further include an outer surface having at least support ribs.

[0014] The inner surface of the outer ring is preferably connected to the housing by optional snap means, corresponding grooves and protrusions, threads, thermal welding, pressure welding, gluing, or other non-limiting means. Preferably, the inner surface of the outer ring is sealed relative to the housing of the filtration element to prevent the feed from flowing between the potential gaps between the inner surface of the outer ring and the housing to the first surface of the filtration membrane.

[0015] The outer ring may further include an outer surface having at least support ribs. Preferably, there are a plurality of support ribs. The plurality of support ribs may be separated into groups, and preferably, the groups of support ribs are placed at uniform intervals. When the filtration unit is placed into a common container, the support ribs of the outer ring may be used to abut against the inner surface of the container, thereby preventing the filtration unit from deviating from the desired position. Optionally, the support ribs may be a circular O-ring around the outer ring to provide a seal between the outer ring and the inner surface of the container.

[0016] The filtration unit may further include two ends, and each of the two ends may include an opening through which the feed may be introduced onto the first surface of the filtration membrane. The filtration unit may further include two or more screening devices, and the screening devices may be placed on both sides of the filtration element. Additionally, the feed flow direction of the filtration unit may be reversible. That is, the feed may be introduced from either one or both sides of the filtration element.

[0017] The filtration element may be directly connected to the screening device by attaching and fixing the screening device to the filtration element. For example, the outer ring of the filtration element may include a connection to the inner surface of the housing.

[0018] The filtration unit may further include a connector for guiding the permeate collected in the central duct of the filtration element and may be further equipped with a sealing device. The connector may be connected to both the screening device and the filtration element by inserting through an orifice of the screening device and into the central duct of the filtration element. The sealing device seals between the connector and the central duct, thereby forming a fluid seal between the feed and the permeate. The connector may further include another sealing device for sealing between the connector and the orifice.

[0019] The filtration element may be indirectly connected to the screening device by assembling the connector to separately connect both the screening device and the filtration element.

[0020] The filtration membrane is selected from the group consisting of: microfiltration membrane, ultrafiltration membrane, nanofiltration membrane, distillation membrane, degassing membrane, ion exchange membrane, and reverse osmosis membrane, preferably a microfiltration membrane and an ultrafiltration membrane.

[0021] The screening device may further include at least two layers of screen body between the orifice and the outer ring. Preferably, the at least two layers of screen body have different screening sizes. When the filtration membrane is a UF or MF membrane, the screen body preferably has a screening size between 50 microns and 400 microns, more preferably between 100 microns and 300 microns, still more preferably between 100 microns and 150 microns.

[0022] There is further provided a filtration system, which includes a container, a feed port, a permeate outlet, optionally a retentate outlet, and at least two filtration units serially positioned within the container as described herein, each of these filtration units including:

[0023] A filtration element having at least one filtration membrane with a first surface in contact with the feed and a second surface in contact with the permeate, at least one end of the filtration element including an opening for introducing the feed onto the first surface of the filtration membrane; and a central duct surrounded by the filtration membrane for collecting the permeate, and

[0024] A screening device, the screening device being connected to an end of a filter element including one or more openings for introducing feed into a first surface of a filter membrane; the screening device includes an orifice substantially positioned at the center of the screening device, an outer ring in an outer periphery of the screening device, and a screening body positioned between the orifice and the outer ring.

[0025] The filter membrane can be surrounded by a housing. The outer ring can include a connection to an inner surface of the housing. The outer ring can further include an outer surface having at least support ribs.

[0026] In some embodiments, at least two filter units are placed in series within a container. The first filter unit and the second filter unit are positioned in this order in the feed flow direction, and for the first filter unit, the screening device is positioned in front of the filter element in the feed flow direction, and for the second filter unit, the screening device is positioned downstream of the filter element in the feed flow direction. The feed flow direction of the filtration system can be reversible. Alternatively, the feed can be introduced from either one or both ends of the filtration system. One or more individual membrane elements positioned in series can be present between the two filter units, without an integrated screening device.

[0027] The filter element of the filter unit within the container can further include two ends, and both of the two ends can include openings through which the feed can be introduced into the first surface of the filter membrane, and each end of the filter element can be connected to at least one screening device. The filtration system can further include another feed port at opposite ends of the filtration system, and the feed can flow to either one or both feed ports of the filtration system. The feed flow direction of the filtration system can be reversible. Alternatively, the feed can be introduced from either one or both sides of the filtration system.

[0028] The filter element is preferably directly connected to the screening device by attaching and fixing the screening device to the filter element. For example, the outer ring of the filter element can include a connection to the inner surface of the housing.

[0029] The filter unit can further include a connector for guiding the permeate collected in a central duct of the filter element and equipped with a sealing device; and the connector is connected to both the screening device and the filter element by inserting it through the orifice of the screening device and into the central duct of the filter element. The sealing device seals between the connector and the central duct, thereby forming a fluid seal between the feed and the permeate. The connector can further include another sealing device for sealing between the connector and the orifice.

[0030] The filter element can be indirectly connected to the screening device by assembling the connector to connect both the screening device and the filter element individually.

[0031] The outer ring may further include an outer surface. The inner surface of the outer ring is preferably connected to the housing by optionally snap devices, corresponding grooves and protrusions, threads, thermal welding, pressure welding, gluing, and other non-limiting means. Preferably, the inner surface of the outer ring is sealed relative to the housing of the filter element to prevent the feed from flowing between the potential gaps between the inner surface of the outer ring and the housing to the first surface of the filter membrane.

[0032] The outer ring may further include an outer surface having at least support ribs. Preferably, there are a plurality of support ribs. The plurality of support ribs may be separated into groups, and preferably, the groups of support ribs are placed at uniform intervals. When the filter unit is placed in a common container, the support ribs of the outer ring can be used to abut against the inner surface of the container, thereby preventing the filter unit from deviating from the desired position. Optionally, the support ribs may be a circular O-ring around the outer ring for sealing between the outer ring and the inner surface of the container.

[0033] The outer ring may further include an inner surface that is connected to the housing by optionally snap devices, corresponding grooves and protrusions, threads, thermal welding, pressure welding, gluing, and other non-limiting means. Preferably, the inner surface of the outer ring is sealed relative to the housing of the filter element to prevent the feed from flowing between the potential gaps between the inner surface of the outer ring and the housing to the first surface of the filter membrane.

[0034] When the filter element is indirectly connected to the screening device by optionally connecting both the screening device and the filter element separately through an assembly connector, the inner surface of the outer ring is not necessarily connected to the housing.

[0035] The connector can be used to direct the permeate collected in the central pipe of the filter element and can also be equipped with a sealing device. There may be a first connector connected to only one filter element. There may also be a second connector connected to two filter elements (i.e., one filter element on each side of the connector). The first connector and the second connector preferably include a sealing device to seal between the connector and the central pipe of the filter element, thereby forming a fluid seal between the feed and the permeate. The first connector may further include another sealing device for sealing between the connector and the orifice. The second connector may further include another sealing device for sealing between the connector and the orifice.

[0036] The filter membrane is selected from the group consisting of: microfiltration membrane, ultrafiltration membrane, nanofiltration membrane, distillation membrane, degassing membrane, ion exchange membrane, and reverse osmosis membrane, preferably microfiltration membrane and ultrafiltration membrane. The type of membrane is independently selected for each membrane element in the filter unit.

[0037] The screening device may further include at least two layers of screen bodies between the orifice and the outer ring. Moreover, the at least two layers of screen bodies have different screening sizes. When the filtration membrane is a UF or MF membrane, the screen body preferably has a screening size between 50 microns and 400 microns, more preferably between 100 microns and 300 microns, and still more preferably between 100 microns and 150 microns.

[0038] The advantages and features characterizing the novelty of the present invention are particularly pointed out in the appended claims and form a part of the claims. However, for a better understanding of the present invention, its advantages, and the objects obtained by its use, reference should be made to the accompanying drawings forming another part of the present invention and to the accompanying descriptive matter, in which one or more preferred embodiments of the present invention are shown and described. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Different types of multi-component filtration systems of the prior art are shown.

[0040] Figure 2 The filtration unit as described herein is shown.

[0041] Figure 3 A front view of the screening device as described herein is shown.

[0042] Figure 4 The connector and the second connector as described herein are shown.

[0043] Figure 5 A filtration system having at least one filtration unit is shown.

[0044] Figure 6 A cross-section of a part of a filtration system having at least two filtration units as described herein is shown.

[0045] Figure 7 (a, b, and c) show the filtration system of the prior art with the original feed flow, the reverse feed flow direction, and the feed from both sides of the filtration system.

[0046] Figure 8 An embodiment of the filtration system as described herein is shown.

[0047] Figure 9 An embodiment of the filtration system as described herein is shown. DETAILED DESCRIPTION

[0048] Reference is now made to the accompanying drawings, in which like reference numerals designate corresponding structures throughout the views, and in particular to Figure 2 and Figure 3 , the filtration unit 10 includes:

[0049] Filter element 2, which has at least one filter membrane 9 (see Figure 5 ), the filter membrane having a first surface in contact with the feed and a second surface in contact with the permeate, at least one end 110 of the filter element including an opening 12 for introducing the feed onto the first surface of the filter membrane; and a central duct 8, which is surrounded by the filter membrane 9 to collect the permeate;

[0050] Sieving device 21, which includes an orifice 23 located substantially in the central part of the sieving device 21, an outer ring 25 in the outer periphery of the sieving device 21, and a screen body 22 between the orifice and the outer ring.

[0051] The outer ring 25 includes an inner surface 252 and an outer surface 253. The outer surface preferably includes at least support ribs 251. The support ribs 251 may extend along the feed direction or at least around a part of the outer periphery of the outer ring 25. Preferably, there are a plurality of support ribs 251 separated into groups, and preferably, the groups of support ribs 251 are placed at relatively uniform intervals. When the filter unit is placed in a common container 3, the support ribs 251 of the outer ring 25 can be used to abut against the inner surface of the container 3 facing it (see Figure 5 ), thereby preventing the filter unit 10 from deviating from the desired or preset position. Alternatively, the support ribs 251 may include a circular O-ring around the outer periphery of the outer ring 25 to seal between the outer ring 25 and the inner surface of the container 3.

[0052] The filter membrane 9 may be surrounded by a housing 11. The housing 11 may be a polymer or metal tube, a cylindrical polymer or metal mesh, a helically wound non-woven fabric, a wound tape, two or more of these types of housings, or any other suitable means of surrounding the filter membrane 9. The housing 11 may be permanent or temporary. For example, the housing 11 may dissolve in water and be washed away after the filter element 2 is put into operation.

[0053] Alternatively, the filter element 2 may not be equipped with a housing 11. The outer ring 25 is provided at one end of the filter element 2. When the filter element 2 is installed in a common container 3, in one embodiment, the support ribs 251 on the outer surface 253 of the outer ring 25 contribute to sealing between the outer ring 25 and the inner surface of the container 3; in another embodiment, the support ribs 251 contribute to creating a space for bypass flow between the filter element 2 and the inner surface of the container 3.

[0054] The inner surface 252 of the outer ring 25 can be connected to the housing 11 by optional snap devices, corresponding grooves and protrusions, threads, thermal welding, pressure welding, gluing, a combination of two or more of these methods, or other non - restrictive means. Preferably, the inner surface 252 of the outer ring 25 is sealed relative to the housing 11 of the filter element 2 to prevent the feed from flowing between the potential gaps between the inner surface 252 of the outer ring 25 and the housing 11 to the first surface of the filter membrane 9.

[0055] The screening device 21 includes an orifice 23 positioned substantially at the center of the screening device 21, an outer ring 25 in the outer periphery of the screening device 21, and a screen body 22 between the orifice and the outer ring. The feed flows through the screen body 22, enters an opening 12 in one end of the filter element 2, and then reaches the first surface of the filter membrane 9. A portion of the feed passes through the filter membrane 9 as permeate to reach the second surface of the filter membrane 9. The remaining portion of the feed is the retentate stream containing the filtering material. The screen body 22 can be a coarse screen (low mesh number) to remove large particles that may damage or block the filter membrane 9 in the filter element 2. Alternatively, the screen body 22 can be a fine screen (high mesh number) to remove larger and smaller particles from the raw material feed. Ideally, there is a seal (not shown) around the orifice 23 to prevent the feed from flowing into the filter element 2 through the space around the orifice 23. The orifice 23 is preferably at the center of the screening device 21. As Figure 2 and Figure 3 shown in a, the periphery of the screen body 22 includes an outer ring 25 to accommodate the screen body 22. The screening device 21 can be a single piece ( Figure 3 a, Figure 3 b), or composed of several pieces combined together ( Figure 3 c).

[0056] As Figure 2 a, Figure 3 b and Figure 3 d shown, the screening device 21 can further include support beams 24 in the area of the screen body 22, which act as stiffeners to strengthen the screening device 21, or as shown in Figure 3 c, as a combined part of several pieces for forming the screening device 21. Different parts of the screening device 21 can be formed into a single piece by gluing or by other connection means. The screening device 21 can be formed as a single piece by injection molding, molding, or even 3D printing. Alternatively, the polymer part of the screening device 21 can be formed as a single piece and combined with other parts made of non - polymer materials.

[0057] The screening device 21 is made of organic or inorganic materials or a combination of both. The organic screening device 21 can be made of any suitable polymer, such as polyolefins (including fluorinated polyolefins), polyamides, polyacrylates, polyesters, copolyesters (such as TritanTM (available from Eastman Chemical Co. in Kingsport, Tennessee), polysulfone (PS), polyethersulfone (PES), sulfonated polyethersulfone (SPS), cellulose, polycarbonate (PC), polytetrafluoroethylene (PTFE), poly(chlorotrifluoroethylene) (PCTFE), fluorinated ethylene polymer (FEP), poly(vinylidene fluoride) (PVDF), poly(vinyl chloride) (PVC), polyacrylonitrile (PAN), acrylonitrile - butadiene - styrene (ABS), and combinations of two or more of these polymers. The inorganic sieving device 21 can be made of metal (such as stainless steel), or ceramic components (such as alumina, zirconia, silica, etc.), and combinations of two or more of these materials.

[0058] The filter membrane 9 is selected from the non - limiting group consisting of: microfiltration membrane, ultrafiltration membrane, nanofiltration membrane, distillation membrane, degassing membrane, ion - exchange membrane, and reverse - osmosis membrane. The filter membrane 9 is made of an organic or inorganic material or a combination of both. The organic filter membrane 9 can be made of any suitable polymer, such as polyolefins (including fluorinated polyolefins), polyamides, polyacrylates, polyesters, copolyesters (including Tritan TM ), polysulfone (PS), polyethersulfone (PES), sulfonated polyethersulfone (SPS), cellulose, polycarbonate, polytetrafluoroethylene (PTFE), poly(chlorotrifluoroethylene) (PCTFE), fluorinated ethylene polymer (FEP), poly(vinylidene fluoride) (PVDF), poly(vinyl chloride) (PVC), polyacrylonitrile (PAN), and combinations of two or more of these polymers. The inorganic filter membrane 9 can be a ceramic membrane made of any suitable material (such as alumina, zirconia, silica, etc., and combinations of two or more of these materials). The ceramic membrane can be synthesized by a sintering method, a sol - gel method, a phase - separation method, a vapor - deposition method, or another suitable method known in the art. The filter membrane 9 can have any shape, such as hollow fibers, tubes, porous fibers, knitted fibers, spiral sheets, pleated sheets, and flat sheets. In an element having more than one membrane 9, the membranes can have one or more of these shapes or be made of more than one of these materials.

[0059] Now refer to Figure 2 c, one or both ends 110 of the filter element 2 include openings 12 to introduce feed to the first surface of the filter membrane 9. Refer to Figure 5 b and Figure 5c. The filtration unit 10 may include two or more screening devices 21, 21', and each end of the filter element 2 is connected to at least one screening device 21, 21'. The two or more screening devices 21, 21' may be placed together in parallel alignment through the orifice 23. The two or more screening devices 21, 21' may be placed on both sides of the filter element 2. The two or more screening devices 21, 21' may be the same, or they may have different screening sizes, material types, or shapes. The feed flow direction of the filtration unit 10 is reversible. Alternatively, the feed may be introduced from either one or both sides of the filtration unit 10. As Figure 5 b and Figure 5 as shown in d, each end of the filter element 2 may be connected to one screening device 21, 21'.

[0060] The filter element 2 is directly connected to the screening device 21 by attaching and fixing the screening device 21 to the filter element 2 (in one embodiment, by fixing the outer ring 25 to the housing 11), as Figure 2 depicted. And in this embodiment, as Figure 4 shown, the connectors 261, 262 may be used to direct the permeate collected in the central duct 8 of the filter element 2. Alternatively, the filtration unit 10 may use the connectors 261, 262 to connect both the filter element 2 and the screening device 21, whereby the filter element 2 is indirectly connected to the screening device 21 of the housing 11 that is not directly connected to the filter element 2 by the outer ring 25 of the filter element 2 by assembling the connectors 261, 262 to connect both the screening device 21 and the filter element 2 individually.

[0061] As Figure 4 shown, the connectors 261, 262 may be hollow tubes having a hollow chamber 28. The connectors 261, 262 direct the permeate collected in the central duct 8 of the filter element 2 and are equipped with a sealing device 27. The connectors 261, 262 are connected to both the screening device 21 and the filter element 2 by being inserted through the orifice 23 of the screening device 21 and into the central duct 8 of the filter element 2, and the sealing device 27 seals between the connectors 261, 262 and the central duct 8, thereby forming a fluid seal between the feed and the permeate. The first connector 261 has a sealing device 27 ( Figure 4 b, Figure 4 d) at one end to connect to only one filter membrane 2 and seal with it. The second connector 262 has a sealing device 27 ( Figure 4 a, Figure 4c), and each end of the connector 262 is connected to and sealed with a filtration membrane 2. The connectors 261, 262 may further include a protruding base 29 to align the sieving device 21 therewith and / or rest thereon. Such a protruding base 29 also enables a constant spacing between adjacent filter elements 2 on both sides of the protruding base 29. The first connector 261 may further include an additional part or an additional part connected to the filtration system 1, such as Figure 8 a and Figure 9 the lid 31 shown in a.

[0062] Now referring to Figure 5 and Figure 6 , the first connector 261 is connected to the filter element 2 by inserting an end with a sealing device 27 into the central duct 8 of the filter element 2. The sealing device 27 forms a fluid seal between the feed and the permeate, i.e., a seal impermeable to gas or liquid. The first connector 261 is connected to the sieving device 21 by inserting one end of the first connector 261 through the orifice 23 of the sieving device 21.

[0063] Optionally, in the absence of the first connector 261, the filter element 2 includes a protrusion (not shown) adapted to be connected to the sieving device 21 by inserting the protrusion through the orifice 23 of the sieving device 21.

[0064] Now referring to Figure 5 (a) to Figure 5 (d), the present invention further provides a filtration system 1, which includes a container 3 and at least one filtration unit 10 as described herein ( Figure 2 shown) within the container 3. The two sides of the container have a plurality of ports, including a feed port 4, a permeate outlet 5, and optionally a retentate outlet 6. The system includes:

[0065] A filter element 2 having at least one filtration membrane 9 with a first surface in contact with the feed and a second surface in contact with the permeate. At least one end 110 of the filter element 2 includes an opening 12 to introduce the feed onto the first surface of the filtration membrane; and a central duct 8 surrounded by the filtration membrane 9 to collect the permeate; and

[0066] A sieving device 21 connected to the end 110 of the filter element 2, the end including one or more openings 12 to introduce the feed onto the first surface of the filtration membrane 9;

[0067] wherein the sieving device 21 includes an orifice 23 substantially located in the central portion of the sieving device 21, an outer ring 25 in the outer periphery of the sieving device 21, and a screen body 22 between the orifice and the outer ring.

[0068] The screening device 21 may further include at least two layers of screen bodies 22 between the orifice 23 and the outer ring 25. And at least two layers of the screen bodies 22 have screening sizes that may be the same or different. When the filtration membrane is a UF or MF membrane, the screen body 22 preferably has a screening size between 50 microns and 400 microns, more preferably between 100 microns and 300 microns, and still more preferably between 100 microns and 150 microns.

[0069] To reduce the occupied space, as Figure 1 shown, at least two sets of filtration units 10 are placed in the container 3. The filtration units 10 may be positioned in series in the horizontal or vertical direction. Preferably, there is an air inlet port 7 for the vertical system, as Figure 1 c and Figure 1 d shown. Preferably, the filtration units 10 are positioned in series in the horizontal direction.

[0070] As Figure 6 、 Figure 8 b and Figure 9 b shown, at least two sets of filtration units 10 may be placed in series in the horizontal direction in the container 3. Preferably, one screening device 21 of one filtration unit 10 is positioned near each side of the filtration system 1. For example, in Figure 8 b and Figure 9 b, the screening device 21 is positioned near one side of the filtration system 1, and another screening device 21' is positioned near the other side of the filtration system 1. The feed flow direction of the filtration system 1 is reversible. During a certain operation period, the feed may be introduced from the feed port 4, and then during another operation period, the feed may be reversed and introduced from the feed port 4'. Alternatively, the feed may be introduced from either one or both sides of the filtration system 1. The feed may be introduced from any one or both of the feed ports 4, 4'.

[0071] Now referring to Figure 6 b, the second connector 262 is connected to two filtration elements 2, 2". Each end of the second connector 262 is connected to one filtration element 2 by inserting the end 27 having a sealing device into the central pipe 8 of the filtration elements 2, 2'. The sealing device 27 forms a fluid seal between the feed and the permeate, that is, a seal that is impermeable to gas or liquid. In some embodiments such as Figure 6 b shown, the second connector 262 is connected to two screening devices 21, 21', and each end of the second connector 262 is connected to the screening device 21 by inserting one end of the second connector 262 through the orifice 23 of the screening device 21.

[0072] As Figure 9As shown in FIG. 2 , there may be one or more separate membrane elements 2″ positioned in series between the two filtration units 10, 10′. The filtration system 1 further includes a second connector 262 to connect every two adjacent membrane elements 2, 2″, and the filtration elements 2, 2″ of the filtration units 10, 10′ are indirectly connected to the screening devices 21, 21′ by assembling connectors 261, 261′ to individually connect both the screening devices 21, 21′ and the filtration elements 2, 2′. Figure 9 As shown in FIG. 1 a , the outer ring 25 may further include an outer surface 253 having at least a support rib 251 , which is a circular O-ring surrounding the outer ring 25 to perform sealing between the outer ring 25 and the inner surface of the container 3 .

[0073] like Figure 8 b, alternatively, two or more filter units 10, 10', 10" are positioned in series, each filter unit 10, 10', 10" includes two or more screening devices 21, 21', and each end of the filter element 10, 10', 10" is connected to at least one screening device 21, 21'. The filter system 1 further includes a second connector 262 to connect every two adjacent membrane elements 10, 10', 10", and the filter elements 10, 10', 10" are directly connected to the screening devices 21, 21' by attaching and fixing the screening devices 21, 21' to the filter elements 10, 10', 10". Figure 8 As shown in FIG. 1 , the inner surface 252 of the outer ring 25 of the screening device 21, 21 ' is connected to the housing 11. The inner surface 252 is connected to the housing 11 by an optional snap-fit device, corresponding grooves and protrusions, threads, heat welding, pressure welding, gluing, a combination of two or more of these methods, or other non-limiting means. Preferably, the inner surface 252 of the outer ring 25 is sealed relative to the housing 11 of the filter element 2 to prevent the feed from flowing between the potential gap between the inner surface of the outer ring 25 and the housing 11 to the first surface of the filter membrane 9.

[0074] like Figure 4 a and Figure 4 As shown in FIG. 3 , the second connector 262 has a hollow shape and has sealing devices 27 at both ends of the second connector 262. The second connector 262 is suitable for connecting every two adjacent membrane elements 2 by inserting each end into the central pipe 8 of the filter element 2 and sealing between the feed and the permeate.

[0075] The filter membrane 9 is selected from the group consisting of: MF membrane, UF membrane, NF membrane, distillation membrane, degassing membrane, ion exchange membrane, and RO membrane. The type of membrane is selected independently for each filtration unit. In other words, the filtration unit may include the same type or different types of filter membranes. Preferably, the filter membrane 9 is selected from MF membrane and UF membrane. The normal cleaning processes for UF membrane and MF membrane include backwashing, air scouring, CEB, CIP, and other methods known to those skilled in the art. The most commonly applied cleaning process is backwashing, which is typically carried out every 20 minutes to 60 minutes based on the feed conditions. When using the filtration unit 10 and the filtration system 1 described herein, when applying cleaning (such as backwashing) to clean the MF membrane and / or UF membrane, the same cleaning process is also applied to the sieving device 21. Therefore, no separate cleaning step or additional cleaning agent is required to clean the sieving device 21 and the filter element 2 separately, which greatly reduces the maintenance time and cost and significantly improves the operation efficiency. In addition, the filter element described herein realizes the one-control-philosophy of the filtration unit 10 having both the sieving device 21 and the filter element 2.

[0076] In the multi-component filtration system 1, the filter membranes 9 of different filter elements 2 may have the same or different materials, pore sizes, morphologies, sizes, shapes, etc. Different filter elements 2 in the filtration system 1 may have the same or different configurations, membrane areas, etc. For example, as Figure 6 shown, the pore size of the filter membrane 9' of the downstream filter element 2' may be greater than or less than the pore size of the filter membrane 9 in the upstream filter element 2.

[0077] The feed flow direction of the filtration unit 10 and the filtration system 1 is reversible. As Figure 7 shown in a, the filtration system 100 includes: a container 3 having a plurality of ports on both sides, including a feed port 4, a permeate outlet 5, and optionally a retentate outlet 6; a first filtration unit 10; and a second filtration unit 10'. As Figure 7 shown in b, when the feed flow is reversed compared to the flow direction in Figure 7 a, the filtration system 100 becomes the filtration system 200. The filtration system 200 includes: a container 3 having a plurality of ports on both sides, including a feed port 4' (previously the retentate outlet 6 of the filter element 100), a retentate outlet 6' (previously the feed port 4 of the filter element 100), a permeate outlet 5; a first group of filtration units 10; and a second group of filtration units 10'. As Figure 7As shown in Fig. c, the filtration system 1 includes a container 3 and two sets of filtration units 10. The two sides of the container have a plurality of ports, including feed ports 4, 4', a permeate outlet 5, and a retentate outlet 6, and the feed is introduced from the two sides of the filtration system 1 through the feed ports 4, 4'. There may also be permeate ports 5 from the two sides of the filtration system 1. Additionally, one end of the central pipe 8 can be inserted by a plug 30 to seal between the permeate and the feed or the retentate, as Figure 5 Fig. a and Figure 5 Fig. c show.

[0078] Reference numerals

[0079]

[0080]

[0081] Although certain preferred embodiments of the present invention have been described and specifically illustrated above, the present invention is not intended to be limited to such embodiments. Rather, it should be understood that although many features and advantages of the present invention, together with details of its structure and function, have been set forth in the foregoing description, the disclosure is illustrative only, and changes may be made in detail, particularly in the shape, size, and arrangement of the various parts, to the extent within the full scope indicated by the broad general meaning of the terms of the appended claims and within the principles of the present invention.

Claims

1. A filtration unit, the filtration unit comprising: A filtration element, the filtration element comprising at least one filtration membrane having a first surface for contacting a feed and a second surface for contacting a permeate; Wherein at least one end of the filtration element comprises one or more openings for introducing the feed to the first surface of the filtration membrane; and wherein the filtration element further comprises a central duct surrounded by the filtration membrane for collecting the permeate; and a screening device connected to the end of the filtration element comprising one or more openings for introducing the feed to the first surface of the filtration membrane; Wherein the screening device comprises an orifice substantially positioned at the center of the screening device, an outer ring in the outer periphery of the screening device, and a screen body between the orifice and the outer ring.

2. The filtering unit according to claim 1, wherein The outer ring comprises an outer surface, the outer surface comprising at least support ridges.

3. The filtering unit according to claim 2, wherein, The filtration membrane is surrounded by a housing, and the outer ring comprises a connection to the inner surface of the housing.

4. The filtering unit according to claim 3, wherein 5. The filtering unit according to claim 4, wherein, The filtration element comprises two ends, and both of the two ends comprise openings through which the feed can be introduced to the first surface of the filtration membrane; wherein the filtration unit comprises two or more screening devices; and wherein each end of the filtration element is connected to at least one screening device.

6. The filtering unit according to claim 1, wherein, The feed flow direction of the filtration unit is reversible.

7. The filtering unit according to claim 6, wherein, The filtration unit further comprises a first connector for guiding the permeate collected in the central duct of the filtration element and equipped with a sealing device; and wherein the first connector is connected to both the screening device and the filtration element by being inserted through the orifice of the screening device and into the central duct of the filtration element; wherein the sealing device seals between the first connector and the central duct, thereby forming a fluid seal between the feed and the permeate.

8. The filtering unit according to claim 7, wherein, The first connector further comprises another sealing device for sealing between the first connector and the orifice.

9. The filtering unit according to claim 1, wherein, The inner surface of the outer ring is sealed relative to the housing of the filtration element.

10. The filtering unit according to claim 9, wherein, The screening device comprises at least two layers of screen body between the orifice and the outer ring.

11. The filtering unit according to claim 1, wherein, At least two layers of screen body between the orifice and the outer ring have different screening sizes.

12. The filtering unit according to claim 11, wherein, The screen body has a screening size between 50 microns and 400 microns.

13. The filtering unit according to claim 12, wherein, The screen body has a screening size between 100 microns and 300 microns.

14. A filtration system, the filtration system comprising a container and at least one filtration unit placed within the container, the container being equipped with a plurality of ports on both sides, including a feed port, a permeate outlet, and optionally a retentate outlet, wherein, The filtration membrane is selected from the group consisting of microfiltration membranes and ultrafiltration membranes. The filtration unit comprises: A filtration element, the filtration element comprising at least one filtration membrane having a first surface for contacting a feed and a second surface for contacting a permeate; Wherein at least one end of the filtration element comprises one or more openings for introducing the feed to the first surface of the filtration membrane; and wherein the filtration element further comprises a central duct surrounded by the filtration membrane for collecting the permeate; and A screening device, the screening device being connected to an end of a filter element including one or more openings for introducing a feed into a first surface of the filter membrane; Wherein, the screening device includes an orifice substantially positioned at the center of the screening device, an outer ring in an outer periphery of the screening device, and a screen body between the orifice and the outer ring.

15. The filtration system according to claim 14, wherein, The filtration system includes at least two filtration units, and near each side of the filtration system, a screening device of one filtration unit is positioned.

16. The filtration system according to claim 15, wherein, The filtration system further includes another feed port at opposite sides of the filtration system, and the feed flows to any one or both feed ports of the filtration system.

17. The filtration system according to claim 16, wherein, The feed flow direction of the filtration system is reversible.

18. The filtration system according to claim 15, wherein, The outer ring includes an outer surface, and the outer surface at least includes support ridges to abut against an inner surface of the container.

19. The filtration system according to claim 15, wherein, The filter membrane is surrounded by a housing, and the outer ring includes a connection to an inner surface of the housing; wherein, the filter element includes two ends, and both of the two ends include openings through which the feed can be introduced into the first surface of the filter membrane; wherein, the filtration unit includes two or more screening devices; and wherein, each end of the filter element is connected to at least one screening device.

20. The filtration system according to claim 15, wherein The filtration unit further includes a first connector and a second connector for guiding permeate collected in a central duct of the filter element and equipped with a sealing device; and wherein, the first connector is connected to only one filtration unit, the second connector is connected to two filtration units; wherein, each connector is connected to the filtration unit by being inserted through the orifice of the screening device and into the central duct of the filter element; wherein, the sealing device seals between each connector and the central duct of the filter element, thereby forming a fluid seal between the feed and the permeate.

21. The filtration system according to claim 20, wherein, The first connector further includes another sealing device for sealing between the connector and the orifice.

22. The filtration system according to claim 21, wherein, The inner surface of the outer ring is sealed relative to the housing of the filter element.

23. The filtration system according to claim 14, wherein, The screening device includes at least two layers of screen body between the orifice and the outer ring.

24. The filtration system according to claim 23, wherein, At least two layers of screening body between the orifice and the outer ring have different screening sizes.

25. The filtration system according to claim 14, wherein, The screen body has a screening size between 50 microns and 400 microns.

26. The filtration system according to claim 25, wherein, The screen body has a screening size between 100 microns and 300 microns.

27. The filtration system according to claim 26, wherein, The filter membrane is selected from the group consisting of microfiltration membranes and ultrafiltration membranes.

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