Internal pressure type filter assembly

Abstract

The utility model relates to an internal pressure type filter assembly which comprises a shell, a filter element and a central pipe, the filter element is arranged in the shell and is provided with an overflowing channel penetrating through the two opposite ends of the filter element, and the overflowing channel is used for draining part of liquid flowing into the shell from one end of the filter element to the other end of the filter element, so that part of liquid can flow into the filter element from one end of the filter element; the other part of liquid can flow into the filter element from the other opposite end of the filter element; the central pipe penetrates through the filter element and extends from one end of the shell to the other end of the shell, an overflowing hole penetrating through the pipe wall of the central pipe is formed in the central pipe, and the overflowing hole is used for allowing liquid filtered by the filter element to pass through, so that the filtered liquid can enter the central pipe and flow out from the end part of the central pipe. Therefore, the liquid is shunted, the problem of low filtering efficiency caused by gradually increased pressure loss of the far end of the filter element due to the fact that the liquid only enters from one end of the filter element is avoided, the filtering efficiency is further improved, and the water production flow is increased.

Description

Technical Field

[0001] The present application relates to the technical field of water purification, and in particular to an internal pressure filter assembly. Background Art

[0002] In order to realize the recycling of water resources, the advantages of membrane treatment technology in wastewater treatment continue to emerge. Hollow fiber ultrafiltration membranes are widely used in the treatment of medium and low concentration wastewater and deep sewage treatment, mainly including drinking water supply terminals, surface water treatment, seawater treatment, sewage reuse and other fields. Hollow fiber ultrafiltration membrane filtration components are divided into internal pressure type and external pressure type according to the filtration direction of the membrane, and the internal pressure filtration component has the advantages of large flux, easy flushing, simple operation process, etc. and is widely used.

[0003] For the internal pressure filter assembly, the working principle during filtration is: raw water enters from one end of the hollow fiber membrane, and is filtered through the membrane wall to produce filtrate. However, during this process, as the raw water continues to penetrate into the membrane, the pressure will be lost, and the water pressure of the raw water far from the water inlet will gradually decrease. Therefore, the water permeability of the end of the hollow fiber membrane close to the water inlet is high, while the water permeability of the end far from the water inlet is low. As the length of the membrane becomes longer, this phenomenon becomes more obvious, resulting in a serious impact on the water permeability of the membrane. Utility Model Content

[0004] Based on this, it is necessary to provide an internal pressure filter assembly that can solve the problem that the water pressure of the raw water is greatly lost during filtration, which seriously affects the water permeability of the membrane.

[0005] According to one aspect of the present application, there is provided an internal pressure filter assembly, comprising:

[0006] case;

[0007] A filter element is arranged in the housing, a liquid inlet cavity and a sewage discharge cavity are respectively formed between the two ends of the filter element and the inner wall of the housing, and the filter element has a flow passage penetrating through the opposite two ends of the filter element, and the two ends of the flow passage are respectively connected with the liquid inlet cavity and the sewage discharge cavity; the filter element includes a hollow filter unit, and the two ends of the hollow filter unit are also respectively connected with the liquid inlet cavity and the sewage discharge cavity;

[0008] The central tube is arranged through the hollow filter unit and extends from one end of the shell to the other end of the shell. The central tube is provided with a flow hole penetrating through the tube wall thereof.

[0009] In one embodiment, there are a plurality of flow passages, and all of the flow passages surround the hollow filter unit along the circumference of the central tube.

[0010] In one embodiment, the filter element further comprises:

[0011] Two sealing rings are spaced apart along the axial direction of the central tube, the outer circumference of each sealing ring is in contact with the inner wall of the shell, and the inner circumference of each sealing ring is in contact with the outer wall of the central tube;

[0012] A flow tube, wherein opposite ends of the flow tube are respectively inserted into a corresponding one of the sealing rings, and the flow passage runs through the opposite ends of the flow tube;

[0013] The inner wall of the shell, the outer wall of the center tube, the outer wall of the flow tube and the side of each sealing ring facing the other sealing ring form a closed cavity, and the hollow filter unit includes a plurality of hollow fiber membranes, and the plurality of hollow fiber membranes are filled in the cavity, and the opposite ends of each hollow fiber membrane are respectively inserted into a corresponding sealing ring.

[0014] In one embodiment, the flow tube is connected to the central tube via a connecting arm.

[0015] In one of the embodiments, the connecting arm has a bracket at one end away from the central tube, the bracket has a slot, and the flow tube is passed through the slot and is snapped into the slot.

[0016] In one of the embodiments, the shape of the inner wall of the slot matches the shape of the outer wall of the flow tube, so that the inner wall of the slot fits the outer wall of the flow tube.

[0017] In one embodiment, there are a plurality of flow tubes, and all of the flow tubes are evenly distributed along the circumference of the central tube.

[0018] In one embodiment, each of the flow tubes is connected to the central tube via at least two of the connecting arms, and all of the connecting arms connected to each of the flow tubes and the central tube are spaced apart along the axial direction of the central tube.

[0019] In one embodiment, the length of each hollow fiber membrane is equal to the length of each flow tube.

[0020] In one embodiment, an annular groove is provided on the outer side of the tube wall of the central tube, the annular groove surrounds the central axis of the central tube, and the flow hole is provided on the bottom wall of the annular groove and penetrates the bottom wall of the annular groove.

[0021] The above-mentioned internal pressure filter assembly, by opening a flow channel running through the opposite ends of the filter element, the two ends of the flow channel are respectively connected to the liquid inlet chamber and the sewage discharge chamber, and by making the filter element include a hollow filter unit, the two ends of the hollow filter unit are also respectively connected to the liquid inlet chamber and the sewage discharge chamber, so that part of the liquid flowing into the shell can be drained from one end of the filter element to the other end of the filter element, so that part of the liquid can flow into the hollow filter unit from one end of the filter element, and the other part of the liquid can flow into the hollow filter unit from the other end of the filter element, and then the filtered liquid enters the central tube through the flow hole of the central tube and is discharged from the end of the central tube, thereby realizing liquid diversion, avoiding the problem of low filtration efficiency caused by the pressure loss at the far end of the filter element gradually increasing due to the liquid entering only from one end of the filter element, thereby improving the filtration efficiency and increasing the water production flow rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the internal structure of an internal pressure filter assembly provided in one embodiment of the present application.

[0023] Figure 2 This is a schematic diagram of the direction of water flow when filtering using an internal pressure filter assembly provided in an embodiment of the present application.

[0024] Figure 3 This is a schematic diagram of the direction of water flow when filtering using an internal pressure filter assembly provided in another embodiment of the present application.

[0025] Figure 4 A cross-sectional schematic diagram of an internal pressure filter assembly provided in one embodiment of the present application.

[0026] Figure 5 This is a schematic diagram of the interconnection between the central tube and the connecting arm of the internal pressure filter assembly provided in an embodiment of the present application.

[0027] Description of reference numerals:

[0028] 10. Internal pressure filter assembly; 100. Shell; 101. Water inlet; 102. Liquid inlet chamber; 103. Sewage discharge chamber; 200. Filter element; 210. Sealing ring; 220. Flow pipe; 221. Flow channel; 230. Hollow filter unit; 231. Hollow fiber membrane; 300. Center tube; 301. Flow hole; 302. Ring groove; 400. Connecting arm; 401. Bracket. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0030] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0031] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0032] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0033] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0034] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0035] As described in the background technology, when the internal pressure filter assembly is filtering, the raw water enters from one end of the hollow fiber membrane and is filtered through the membrane wall to produce filtrate. However, in this process, as the raw water continues to penetrate into the membrane, the pressure will be lost and the raw water pressure will gradually decrease. Therefore, the water permeability of the hollow fiber membrane close to the water inlet end is high, while the water permeability of the end far from the water inlet end is low. As the length of the membrane becomes longer, this phenomenon becomes more obvious, resulting in a serious impact on the water permeability of the membrane.

[0036] To this end, the present application provides an internal pressure filter assembly for diverting liquid before filtering, so as to overcome the above-mentioned problem that the water pressure loss of raw water is large, resulting in serious impact on the water permeability of the membrane.

[0037] The following uses the internal pressure filter assembly for filtering raw water as an example to illustrate the structure of the internal pressure filter assembly. It is understandable that in other embodiments, the internal pressure filter assembly of the present application is not limited to filtering raw water, but can also filter any liquid, which is not limited here.

[0038] like Figure 1 , which is a schematic diagram of the internal structure of an internal pressure filter assembly 10 provided in one embodiment of the present application, the internal pressure filter assembly 10 (hereinafter referred to as the filter assembly) provided in one embodiment of the present application comprises a housing 100, a filter element 200 and a central tube 300, wherein the housing 100 is a hollow cylindrical structure, and has a cap at both ends ( Figure 1100 ), is used to form a closed accommodating chamber inside the shell 100, one of the seals is provided with a water inlet 101 for raw water to enter the accommodating chamber; the filter element 200 is provided in the accommodating chamber, and is used to filter the raw water entering the accommodating chamber to prepare purified water that meets the drinking standards of people; the central tube 300 is coaxially penetrated by the filter element 200 and the shell 100, and extends from one end of the shell 100 to the other end of the shell 100, and its tube wall is provided with a flow hole 301 penetrating the tube wall, for the purified water filtered by the filter element 200 to pass through, so that the purified water can enter the central tube 300, and be discharged from the end of the central tube 300 for people to use.

[0039] Preferably, in order to solve the above-mentioned problem that the water pressure of the raw water is greatly lost during the filtration process, resulting in serious impact on the water permeability of the membrane, in one embodiment, a liquid inlet chamber 102 and a sewage discharge chamber 103 are formed between the two ends of the filter element 200 and the inner wall of the shell 100, and the filter element 200 has a flow channel 221 running through the opposite ends of itself, and the two ends of the flow channel 221 are respectively connected to the liquid inlet chamber 102 and the sewage discharge chamber 103, which is used to divert part of the raw water flowing into the shell 100 from one end of the filter element 200 to the other end of the filter element 200. The filter element 200 includes a hollow filter unit 230, and both ends of the hollow filter unit 230 are respectively connected to the liquid inlet chamber 102 and the sewage discharge chamber 103. The central tube 300 is penetrated through the hollow filter unit 230, so that part of the raw water can flow into the hollow filter unit 230 from one end of the filter element 200, and after being filtered by the hollow filter unit 230, enter the central tube 300 through the flow hole 301. Another part of the raw water can flow into the hollow filter unit 230 from the other end of the filter element 200, and after being filtered by the hollow filter unit 230, also enter the central tube 300 through the flow hole 301.

[0040] Specifically, Figure 1 As shown, the filter element 200 also includes two sealing rings 210 (only one is shown in the figure), a flow tube 220, and the hollow filter unit 230 includes a plurality of hollow fiber membranes 231. The two sealing rings 210 are arranged at intervals along the axial direction of the central tube 300. The outer circumference of each sealing ring 210 is attached to the inner wall of the housing 100, and the inner circumference of each sealing ring 210 is attached to the outer wall of the central tube 300. The opposite ends of the flow tube 220 are respectively inserted into a corresponding sealing ring 210. The flow channel 221 is opened in the flow tube 220 and passes through the opposite ends of the flow tube 220. The inner wall of the housing 100, the outer wall of the central tube 300, the outer wall of the filter tube, and the side of each sealing ring 210 facing the other sealing ring 210 form a closed cavity. The plurality of hollow fiber membranes 231 are filled in the above-mentioned closed cavity, and the opposite ends of each hollow fiber membrane 231 are inserted into a corresponding sealing ring 210.

[0041] The structure of the hollow fiber membrane 231 is prior art and will not be elaborated on here. It is well known that the hollow fiber membrane 231 is a slender hollow strip structure with open ends and an inner diameter much smaller than the flow tube 220. A plurality of tiny filter holes are provided on the membrane wall. After the raw water enters the interior of the hollow fiber membrane 231 from the end of the hollow fiber membrane 231, impurities cannot pass through the filter holes, and clean water without impurities can flow through the filter holes to the outside of the hollow fiber membrane 231 to achieve filtration.

[0042] Thus, by setting a flow tube 220 with a diameter much larger than that of the hollow fiber membrane filament 231 in the filter element 200, when the filter assembly 10 is used for filtering, the raw water entering the liquid inlet cavity 102 from the water inlet 101 opened at one end of the shell 100 will generate pressure transmission when flowing in the shell 100, so that it can be diverted by the flow tube 220. Specifically, Figure 2 and Figure 3 As shown by the arrow in the figure, a part of the raw water enters the hollow fiber membrane 231 from the end of the hollow fiber membrane 231 close to the liquid inlet chamber 102; while the other part of the raw water can be diverted from the flow channel 221 of the flow tube 220 to the end of the flow tube 220 away from the water inlet 101 under the action of pressure transmission, that is, it is diverted to the sewage chamber 103, and after being blocked by the head, the flow path is changed, and it returns to the end of the hollow fiber membrane 231 away from the water inlet 101 and flows into the hollow fiber membrane 231, and then The water enters the center tube 300 through the flow hole 301 opened in the center tube 300 and flows out from the end of the center tube 300, so that raw water can enter the opposite ends of the hollow fiber membrane 231 and be filtered by the hollow fiber membrane 231, avoiding the problem that the raw water can only enter from one end of the hollow fiber membrane 231, resulting in low pressure loss and high filtration efficiency at the near end of the filter element 200, and low filtration efficiency caused by the gradually increasing pressure loss at the far end of the filter element 200, thereby improving the filtration efficiency and increasing the water production flow. In addition, the sewage in the sewage discharge chamber 103 can also enter the hollow fiber membrane 231 from the end of the hollow fiber membrane 231 away from the liquid inlet chamber and be filtered, further improving the filtration efficiency.

[0043] It is understandable that the filtered water can be Figure 2 As shown in FIG. , the gas is discharged from both ends of the central tube 300 simultaneously, or as shown in FIG. Figure 3 As shown in , the filtered clean water can be discharged from one end of the central tube 300, which is not limited here.

[0044] In a preferred embodiment, the length of each hollow fiber membrane filament 231 is equal to that of each flow tube 220, so that a portion of the raw water can be diverted from the flow channel 221 to the end of the flow tube 220 away from the water inlet 101, and after flowing out of the flow channel 221, it can quickly enter the hollow fiber membrane filament 231 to ensure the water production flow rate.

[0045] Optionally, there are a plurality of flow passages 221, and all flow passages 221 surround the hollow filter unit 230 along the circumference of the central tube 300. Specifically, Figure 4 As shown, in the embodiment in the figure, there are multiple flow tubes 220, and the multiple flow tubes 220 are arranged at intervals along the circumferential direction of the central tube 300, so as to ensure that more raw water can be diverted to the end of the flow tube 220 away from the water inlet 101, thereby ensuring that the amount of raw water entering the hollow fiber membrane 231 from the opposite ends of the hollow fiber membrane 231 is basically equal, further avoiding the occurrence of uneven filtration efficiency at both ends of the hollow fiber membrane 231. It can be understood that the number of flow tubes 220 is not particularly limited, and can be two or more.

[0046] Further, in order to prevent the flow tube 220 from changing its position in the housing 100 under the action of water pressure, please continue to refer to Figure 4 Each flow tube 220 is connected to the central tube 300 through a connecting arm 400, so that each flow tube 220 is fixed in the housing 100. Specifically, there are also multiple connecting arms 400, which are arranged around the central axis of the central tube 300 and correspond to the multiple flow tubes 220 one by one. Each connecting arm 400 has a bracket 401 at one end away from the central tube 300, and the bracket 401 has a slot, and the flow tube 220 is inserted into the slot and clamped in the slot, so that the flow tube 220 is fixed on the connecting arm 400 by connecting with the bracket 401.

[0047] Preferably, the inner wall shape of the slot matches the outer wall shape of the flow tube 220. Exemplarily, the flow tube 220 is cylindrical. Figure 5 As shown, the inner wall of the slot is arc-shaped or circular, so that the inner wall of the slot fits the outer wall of the flow tube 220, so that the central axis of the flow tube 220 is parallel to the central axis of the center tube 300, ensuring the uniform flow rate of the water flow. On this basis, the outer wall of the flow tube 220 and the inner wall of the slot are bonded and fixed to each other, and because the shape of the inner wall of the slot matches the shape of the outer wall of the flow tube 220, the outer wall of the flow tube 220 and the inner wall of the slot can be bonded more firmly, so that the flow tube 220 can be fixed more firmly on the bracket 401.

[0048] It is worth noting that, since each flow tube 220 is relatively long, in order to further ensure that the central axis of the flow tube 220 is parallel to the central axis of the central tube 300, the flow tube 220 can be more firmly fixed in the housing 100 to ensure a uniform flow rate of the water flow. Each flow tube 220 is connected to the central tube 300 through at least two connecting arms 400, and all the connecting arms 400 connected to each flow tube 220 and the central tube 300 are arranged at intervals along the axial direction of the central tube 300. In this way, the flow tube 220 is supported by the support frame at different positions in its own axial direction, thereby achieving the above purpose.

[0049] It should be noted that the structure of the filter element 200 is not limited to the above structure, as long as it has a flow channel 221 that can drain the raw water and has a filtering function so that the raw water can be filtered into clean water and then enter the central tube 300.

[0050] In addition, as mentioned above, the clean water filtered by the hollow fiber membrane filaments 231 will eventually be collected into the central tube 300 through the flow holes 301 and discharged from the end of the central tube 300. However, since the membrane filaments are slender and long strip-shaped structures, the hollow fiber membrane filaments 231 located around the central tube 300 will move under the drive of the water flow, and thus may adhere to the wall of the central tube 300, resulting in blockage of the flow holes 301 opened in the wall of the central tube 300, thereby causing water production to be blocked.

[0051] In order to solve this problem, in a preferred embodiment, Figure 1 and Figure 5 As shown, an annular groove 302 is provided on the outer side of the tube wall of the central tube 300 , and the annular groove 302 surrounds the central axis of the central tube 300 . The flow hole 301 is provided on the bottom wall of the annular groove 302 and penetrates the bottom wall of the annular groove 302 .

[0052] In this way, through the above-mentioned arrangement, even if the hollow fiber membrane filaments 231 located around the central tube 300 are attached to the tube wall of the central tube 300 under the drive of the water flow, due to the existence of the annular groove 302, the flow hole 301 is opened on the bottom wall of the annular groove 302, and the hollow fiber membrane filaments 231 cannot cause blockage to the flow hole 301, thereby ensuring smooth water production.

[0053] In summary, the internal pressure filter assembly 10 provided by the present application, on the one hand, by setting the flow tube 220 to form the flow channel 221, after the raw water enters the shell 100, part of the raw water can be diverted to the end of the hollow fiber membrane filament 231 away from the water inlet 101, so that the raw water enters both opposite ends of the hollow fiber membrane filament 231, ensuring the uniform water permeability of the hollow fiber membrane filament 231, improving the water permeability, and solving the problem of uneven water permeability of the membrane filament due to pressure loss when the water flow enters the hollow fiber membrane filament 231. On the other hand, by opening an annular groove 302 on the tube wall of the central tube 300, the flow hole 301 is opened on the bottom wall of the annular groove 302, avoiding the hollow fiber membrane filament 231 from blocking the water hole of the central tube 300 when water is produced, so that the water flow is smooth, solving the problem that the hollow fiber membrane filament 231 is easy to block the water hole of the central tube 300 when the internal pressure filter assembly 10 produces water, resulting in unsmooth water production.

[0054] Finally, it should be noted that when the internal pressure filter assembly 10 provided in the present application is in use, multiple internal pressure filter assemblies 10 can be used in series, that is, the heads located at the opposite ends of the shell 100 are provided with through holes connecting the inside of the shell 100 and the outside of the shell 100, and the two ends of the flow tube 220 are respectively inserted into the through holes, so that the flow tube 220 of each internal pressure filter assembly 10 is connected with the flow tube 220 of the adjacent internal pressure filter assembly 10. In this way, part of the raw water entering each internal pressure filter assembly 10 can also be drained by the flow tube 220 to the next adjacent internal pressure filter assembly 10. In this way, the water permeability of the hollow fiber membrane filaments 231 in each internal pressure filter assembly 10 can be uniform, and the purpose of increasing the water permeability can also be achieved.

[0055] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0056] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. An internal pressure filter assembly, characterized in that: include: case; A filter element is arranged in the housing, a liquid inlet cavity and a sewage discharge cavity are respectively formed between the two ends of the filter element and the inner wall of the housing, and the filter element has a flow passage penetrating through the opposite two ends of the filter element, and the two ends of the flow passage are respectively connected with the liquid inlet cavity and the sewage discharge cavity; the filter element includes a hollow filter unit, and the two ends of the hollow filter unit are also respectively connected with the liquid inlet cavity and the sewage discharge cavity; The central tube is arranged through the hollow filter unit and extends from one end of the shell to the other end of the shell. The central tube is provided with a flow hole penetrating through the tube wall thereof.

2. The internal pressure filter assembly according to claim 1, characterized in that: There are a plurality of flow passages, and all of the flow passages surround the hollow filter unit along the circumference of the central tube.

3. The internal pressure filter assembly according to claim 1, characterized in that: The filter element also includes: Two sealing rings are spaced apart along the axial direction of the central tube, the outer circumference of each sealing ring is in contact with the inner wall of the shell, and the inner circumference of each sealing ring is in contact with the outer wall of the central tube; A flow tube, wherein opposite ends of the flow tube are respectively inserted into a corresponding one of the sealing rings, and the flow passage runs through the opposite ends of the flow tube; The inner wall of the shell, the outer wall of the center tube, the outer wall of the flow tube and the side of each sealing ring facing the other sealing ring form a closed cavity, and the hollow filter unit includes a plurality of hollow fiber membranes, and the plurality of hollow fiber membranes are filled in the cavity, and the opposite ends of each hollow fiber membrane are respectively inserted into a corresponding sealing ring.

4. The internal pressure filter assembly according to claim 3, characterized in that: The flow tube is connected to the central tube via a connecting arm.

5. The internal pressure filter assembly according to claim 4, characterized in that: The end of the connecting arm away from the central tube is provided with a bracket, the bracket has a clamping slot, and the flow tube is passed through the clamping slot and clamped in the clamping slot.

6. The internal pressure filter assembly according to claim 5, characterized in that: The inner wall shape of the clamping slot matches the outer wall shape of the flow tube, so that the inner wall of the clamping slot fits the outer wall of the flow tube.

7. The internal pressure filter assembly according to any one of claims 4 to 6, characterized in that: There are a plurality of flow tubes, and all of the flow tubes are evenly distributed along the circumference of the central tube.

8. The internal pressure filter assembly according to claim 7, characterized in that: Each of the flow tubes is connected to the central tube via at least two of the connecting arms, and all of the connecting arms connected to each of the flow tubes and the central tube are arranged at intervals along the axial direction of the central tube.

9. The internal pressure filter assembly according to claim 3, characterized in that: The length of each hollow fiber membrane is equal to the length of each flow tube.

10. The internal pressure filter assembly according to claim 1, characterized in that: An annular groove is provided on the outer side of the tube wall of the central tube, and the annular groove surrounds the central axis of the central tube. The flow hole is provided on the bottom wall of the annular groove and penetrates the bottom wall of the annular groove.

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