Filter with semi-occluded end cap structure

Abstract

The application relates to the technical field of filters and discloses a filter with a semi-shielding end cover structure, a paper core formed by repeatedly bending filter paper is embedded in the closed end of a shell through filter paper glue, is connected to the lower end of a filter module, a closed end cover and a supporting spring are omitted, the height of the shell is shortened, oil flow to the area containing the supporting spring is avoided to form a turbulent flow, the folds of the upper end of the paper core are sealed through sealing glue between the folds, the outer diameter of the bonding surface of an open end cover is smaller than the outer diameter of the paper core, the bonding surface is sealed and bonded to the top end of the filter module through the sealing glue, the upper end of the filter module is sealed through a small amount of sealing glue and a combination of the open end cover which is partially shielded, material cost can be saved, a flange ring is inserted into a ring and is in a radial interference fit, the inner side and the outer side of the paper core are sealed, an inner sealing ring is omitted, under the premise of ensuring the function of the filter, the oil path is simplified, the resistance is reduced, the number of parts is reduced, the reliability is improved, and the environmental protection is enhanced.

Description

Technical Field

[0001] This invention relates to the field of filter technology, and more particularly to a filter with a semi-obscured end cap structure. Background Technology

[0002] In modern engine development, compact structure, low cost, lightweight design, and environmental friendliness are among the main evaluation indicators. Before entering the engine, fuel or engine oil needs to pass through a filtration system to remove contaminants. The main component of the filtration system is the filter, with spin-on filters being the most widely used.

[0003] Traditional fuel filters or oil filters consist of multiple parts, including a filter medium, an open end cap, a closed end cap, a support spring, an inner sealing ring, a housing, a threaded cover plate, and an outer sealing ring. Regardless of the type of product, current designs suffer from drawbacks such as a large number of parts, a large size, a heavy product, and complex assembly, resulting in high design and manufacturing costs. Summary of the Invention

[0004] The purpose of this invention is to provide a filter with a semi-enclosed end cap structure, which simplifies the oil circuit and reduces resistance, reduces the number of parts, reduces product weight, and saves material costs while ensuring the filter function; at the same time, it improves reliability and enhances environmental friendliness.

[0005] To achieve this objective, the present invention adopts the following technical solution: A partially obscured end cap structure filter includes: The outer casing has an open end and a closed end; The filter module is coaxially placed inside the housing. The filter module includes a paper core, which is a hollow ring structure and made of V-shaped filter paper joined end to end. The bottom end of the paper core is embedded with the closed end by filter paper glue, and the folds of the inward opening at the top end of the paper core are sealed with sealing glue. A threaded cover plate, comprising an integral and coaxially arranged cover plate body and a flanged ring, wherein the cover plate body has an oil inlet, the flanged ring is located on the inner ring of the cover plate body and is bent downward in a direction parallel to the axial direction of the cover plate body, the inner ring of the flanged ring is provided with connecting threads, and the hollow part of the flanged ring is configured as an oil outlet, the oil outlet being connected to the hollow part of the filter module; An open end cap includes an integral and coaxially arranged adhesive surface and a mating ring. The outer diameter of the adhesive surface is smaller than the outer diameter of the paper core. The adhesive surface is sealed to the top of the paper core by the sealing adhesive. The mating ring is located on the inner ring of the adhesive surface, and the inner ring of the mating ring is interference-fitted with the outer ring of the flange ring. An external sealing module is connected to the cover plate body, and the outer ring of the external sealing module is connected to the opening end.

[0006] As an optional technical solution for a filter with a semi-obscured end cap structure, the open end cap is made of thermoplastic polyurethane elastomer, and the top of the mating ring is higher than the top of the adhesive surface.

[0007] As an optional technical solution for a filter with a semi-obscured end cap structure, the open end cap is bonded to the top of the filter module by hot plate welding.

[0008] As an optional technical solution for a filter with a semi-obscured end cap structure, the cover plate body is inclined downward on the side near the flange ring, and the top of the mating ring is flush with the top of the adhesive surface.

[0009] As an optional technical solution for a filter with a semi-obscured end cap structure, the outer periphery of the open end cap is provided with multiple positioning protrusions at intervals, and the positioning protrusions all abut against the inner wall of the outer shell.

[0010] As an optional technical solution for a semi-enclosed end cap structure filter, the bottom of the housing is provided with a constriction, the outer diameter of the constriction is smaller than the outer diameter of the open end, and the bottom end of the filter module is inserted into the constriction.

[0011] As an optional technical solution for a filter with a semi-obstructed end cap structure, the closed end is provided with an inner protrusion.

[0012] As an optional technical solution for a semi-obscured end cap structure filter, the filter module also includes a central tube, which is disposed inside the paper core and has multiple circumferential openings.

[0013] As an optional technical solution for a semi-enclosed end cap structure filter, the filter paper adhesive at the bottom of the paper core is cured and formed by a mold, and the cured filter paper adhesive is snapped onto the inner ring of the closed end.

[0014] As an optional technical solution for a filter with a semi-obscured end cap structure, the outer sealing module includes a sealing ring seat and an outer sealing ring. The sealing ring seat is connected to the cover plate body. The sealing ring seat is provided with an outer ring seat and a sealing groove. The outer ring seat is connected to the open end, and the outer sealing ring is placed in the sealing groove.

[0015] The beneficial effects of this invention are: The semi-enclosed end cap structure filter provided by this invention includes a housing, a filter module, a threaded cover plate, an open end cap, and an outer sealing module. The housing has an open end and a closed end; the filter module's paper core has a hollow annular structure, made of V-shaped filter paper joined end to end. The repeated bending pleats expand the filter contact surface, which is beneficial for optimizing the filtration rate. The folds at the upper end of the paper core that open inward are sealed with sealing adhesive; the bottom end is nested in the closed end with filter paper adhesive, which seals the lower end of the filter module. In this application, the housing replaces the closed end cap, and the lower end of the filter module is directly fitted and connected to the housing with filter paper adhesive, which eliminates the need for the closed end cap and support spring, and the height of the housing can be further shortened; it can also prevent oil from flowing into the area containing the support spring and forming turbulence, thus reducing oil resistance.

[0016] The threaded cover plate includes an integral and coaxially arranged cover plate body and a flanged ring. The cover plate body has an oil inlet. The flanged ring is located on the inner ring of the cover plate body and is bent downwards in a direction parallel to the axial direction of the cover plate body. The inner ring of the flanged ring has connecting threads for connecting the filter to the mounting base. The hollow part of the flanged ring is set as an oil outlet, which communicates with the hollow part of the filter module. The open end cap includes an integral and coaxially arranged adhesive surface and a mating ring. The outer diameter of the adhesive surface is smaller than the outer diameter of the paper core. The adhesive surface is sealed to the top of the filter module with sealing glue, which seals the top of the paper core. Using a small amount of sealing glue and the combination of the partially obscured open end cap to seal the upper end of the filter module can save material costs. The mating ring is located on the inner ring of the adhesive surface. The flanged ring is inserted into the mating ring and there is a radial interference fit between the two, which seals the inner and outer sides of the paper core. The semi-enclosed end cap structure filter design in this application forms a seal by directly interfering with the open end cap and the threaded cover plate, eliminating the need for an inner sealing ring and further reducing the number of parts.

[0017] This semi-enclosed end cap structure filter, while ensuring filter functionality, optimizes the existing filter structure, reducing the number of parts, shortening the product height, and lowering the product weight. It also simplifies the oil circuit and reduces oil circuit resistance, thereby minimizing design and manufacturing costs. This results in reduced design and manufacturing costs while improving reliability and enhancing environmental friendliness. Attached Figure Description

[0018] Figure 1 This is a cross-sectional schematic diagram of a semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 2 This is a cross-sectional schematic diagram of the outer shell of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 3 This is a schematic diagram of the oil circuit of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 4 This is a schematic diagram of the outer shell structure of a semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 5 This is a cross-sectional schematic diagram of the housing, filter module, and open end cap in one embodiment of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention. Figure 6 This is a schematic diagram of the outer shell structure in another embodiment of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 7 This is a schematic diagram of the paper core structure of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of the central tube of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 9 This is a schematic diagram of the threaded cover plate of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 10 This is a cross-sectional schematic diagram of the threaded cover plate of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 11 This is a cross-sectional schematic diagram of the open end cap of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 12 This is a schematic diagram of the threaded cover plate in another embodiment of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 13 This is a cross-sectional schematic diagram of the open end cap in another embodiment of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention. Figure 14 This is a cross-sectional schematic diagram of the open end cap and threaded cover plate in another embodiment of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention. Figure 15 This is a schematic diagram of the sealing ring seat of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention; Figure 16 This is a cross-sectional schematic diagram of the sealing ring seat of the semi-obstructed end cap structure filter provided in a specific embodiment of the present invention.

[0019] In the picture: 100. Outer shell; 101. Open end; 102. Closed end; 110. Narrowing; 120. Inner protrusion; 210. Paper core; 220. Center tube; 300. Threaded cover plate; 301. Oil inlet; 302. Oil outlet; 303. Connecting thread; 310. Flanged ring; 400. Open end cap; 410. Mating ring; 420. Adhesive surface; 510. Sealing ring seat; 511. Outer ring seat; 512. Sealing groove; 520. Outer sealing ring; 910, Filter paper adhesive; 920, Sealing adhesive. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0021] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] In the description of this embodiment, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0024] like Figures 1 to 16As shown, this invention discloses a semi-obscured end cap structure filter, including a housing 100, a filter module, a threaded cover plate 300, an open end cap 400, and an external sealing module. The housing 100 is a cylindrical stamped part with an open end 101 and a closed end 102. The filter module is coaxially placed inside the housing 100 and is used to filter dirty oil. The filter module includes a paper core 210, which serves as the filter medium and is configured as a hollow annular structure. It is made of V-shaped filter paper joined end to end, resembling an accordion. The repeated folds expand the filter contact surface, which is beneficial for optimizing the filtration rate. The bottom end of the paper core 210 is fitted and inserted into the closed end 102 via filter paper adhesive 910, sealing the lower end of the filter module. The lower end of the paper core 210 with filter paper adhesive 910 is directly nested inside the closed end 102 of the housing 100. The folds of the upper end of the paper core 210, which open inwards, are sealed with sealing adhesive 920. Among them, filter paper adhesive 910 generally uses PVC (polyvinyl chloride resin) adhesive or two-component polyurethane adhesive that can be cured by heat; sealing adhesive 920 uses a safer and more environmentally friendly hot melt adhesive.

[0025] In traditional structures, the lower end of the filter module is typically glued to a closed end cap. The semi-enclosed end cap structure filter of this application uses a portion of the outer shell 100 to replace the function of the closed end cap. The lower end of the filter module is directly glued to the outer shell 100 using filter paper adhesive 910, eliminating the need for a closed end cap. Similarly, in traditional structures, a support spring is provided between the closed end cap and the outer shell 100 to provide axial support for the filter module. In the semi-enclosed end cap structure filter of this application, after replacing the closed end cap with the outer shell 100, the filter module is axially fixed to the outer shell 100, eliminating the need for a support spring. Compared to the traditional structure where the outer shell 100 needs space to accommodate the support spring, this design, by eliminating the support spring and other components, allows for a further reduction in the height of the outer shell 100.

[0026] Understandably, in traditional structures, after the oil enters the filter, it flows towards the area housing the support spring, easily creating turbulence and increasing oil resistance. The semi-enclosed end cap structure filter design in this application eliminates the space for the support spring, reducing turbulence and thus lowering oil resistance. Overall, while maintaining the interchangeability of all components, optimizing the existing filter structure not only reduces the number of parts, shortens the product height, and lowers the product weight, but also reduces assembly complexity. This results in reduced design and manufacturing costs, while simultaneously improving reliability and enhancing environmental friendliness.

[0027] refer to Figure 1 , Figure 7 and Figure 8The filter module also includes a central tube 220, which is located inside the paper core 210 and provides support for the paper core 210. The central tube 220 is a cylindrical part with multiple circumferential openings.

[0028] In this embodiment, the paper core 210, after being folded, surrounds the outer periphery of the central tube 220, and its lower end is bonded to the filter paper adhesive 910 to achieve a seal. The filter paper adhesive 910 that can be demolded from the mold is selected. The bottom end of the paper core 210 is molded and then demolded. The cured filter paper adhesive 910 is snapped into the inner ring of the closed end 102. It is not necessary to fill the gap between the bottom end of the paper core 210 and the closed end 102. The seal is only performed in the circumferential direction at the snapping position. While ensuring the sealing effect, it can reduce the amount of filter paper adhesive 910 and reduce the weight of the semi-obstructed end cap structure filter. Furthermore, it can reasonably control the curing distribution area of ​​the filter paper adhesive 910, avoid problems such as excessive glue overflow affecting the filtration rate or insufficient glue causing sealing failure, ensure stable filtration function and save material costs.

[0029] For example, the bottom end of the paper core 210 can also be directly bonded to the closed end 102 by means of filter paper adhesive 910. By directly injecting the filter paper adhesive 910 between the bottom end of the paper core 210 and the closed end 102 for bonding, the structure is stable and the sealing effect is excellent, and the assembly operation is simpler and more efficient.

[0030] In this embodiment, reference Figures 9 to 11 The threaded cover plate 300 is a disc-shaped stamped part, including an integral and coaxially arranged cover plate body and a flange ring 310. The cover plate body has an oil inlet 301. The flange ring 310 is located in the inner ring of the cover plate body and is bent downward in a direction parallel to the axial direction of the cover plate body. The inner ring of the flange ring 310 is provided with a connecting thread 303, which is used to connect the filter to the mounting base. The hollow part of the flange ring 310 is set as an oil outlet 302, which is connected to the hollow part of the filter module.

[0031] A novel open end cap 400 is designed, comprising an integral and coaxially arranged adhesive surface 420 and a mating ring 410. The outer diameter of the adhesive surface 420 is smaller than the outer diameter of the paper core 210. The adhesive surface 420 is sealed and bonded to the top of the filter module by sealing adhesive 920, and the adhesive surface 420 is located below the cover plate body. The mating ring 410 is located on the inner ring of the adhesive surface 420, and the inner ring of the mating ring 410 can be interference-fitted with the outer ring of the flange ring 310. The upper end of the filter module is sealed by combining the open end cap 400 with a small amount of sealing adhesive 920 for sealing and partial obstruction, which can save material costs.

[0032] The flanged ring 310 is inserted into the mating ring 410, and a radial interference fit is made between them, providing a seal between the inner and outer sides of the paper core 210. The semi-obstructed end cap structure filter design in this application directly forms a seal between the open end cap 400 and the threaded cover plate 300 through an interference fit, eliminating the need for an inner sealing ring between the open end cap 400 and the threaded cover plate 300 in traditional structures. This eliminates the need for an inner sealing ring and further reduces the number of components.

[0033] like Figure 1 , Figure 15 and Figure 16 As shown, the outer sealing module includes a sealing ring seat 510 and an outer sealing ring 520. The sealing ring seat 510 is located above the threaded cover plate 300 and is a disc-shaped stamped part. The sealing ring seat 510 is connected to the cover plate body by welding or riveting. The sealing ring seat 510 is provided with an outer ring seat 511 and a sealing groove 512. The outer ring seat 511 is connected to the open end 101 and they interlock to ensure stable assembly. The outer sealing ring 520 is placed in the sealing groove 512 and is a circular rubber part. The outer sealing ring 520 seals against the mounting base and is used to seal the filter of the semi-obstructed end cover structure and the mounting base.

[0034] Specifically, such as Figure 3 As shown, dirty oil (fuel or engine oil) enters the interior of the semi-enclosed end cap structure filter from the oil inlet 301, flows directly downward through the gap between the two folds of the paper core 210, that is, the area outside the outer diameter of the open end cap 400, and reaches the outer surface of the paper core 210 for filtration. Then it passes through the paper core 210. After being filtered by the paper core 210, the dirty oil becomes clean oil, and then passes through the central tube 220, and finally flows out of the oil outlet 302 for use by downstream devices (combustion or lubrication).

[0035] This semi-enclosed end cap structure filter further optimizes the product structure while ensuring the filter's functionality. It simplifies the oil circuit and reduces resistance, thereby reducing the number of parts. As a result, the product's height and weight can be further reduced, and assembly is simplified. This minimizes design and manufacturing costs.

[0036] For example, when there is no means to control the coaxiality between the open end cap 400 and the housing 100 during the assembly process, multiple positioning protrusions are evenly distributed on the outer periphery of the open end cap 400, and the multiple positioning protrusions abut against the inner wall of the housing 100. This can improve the coaxiality between the open end cap 400 and the housing 100, making it easier for the threaded cover plate 300 to be inserted into the open end cap 400 and the housing 100 more smoothly.

[0037] In this embodiment, when the customer requires the filter to be more environmentally friendly and lightweight, the open end cap 400 is made of thermoplastic polyurethane elastomer (TPU). That is, the open end cap 400 uses TPU end caps, whose performance is between that of plastic and rubber. It possesses excellent mechanical properties such as high strength, high elasticity, high wear resistance, and high flexibility, and also has resistance to oil, solvents, and common chemicals. Generally, the cover body of the threaded cover plate 300 is inclined upwards on the side near the flange ring 310, and the top of the mating ring 410 should be higher than the top of the bonding surface 420. The open end cap 400 is bonded to the top of the filter module via hot plate welding. Using a hot plate welding process, the surface of the plastic end cap is heated and melted, bonding the plastic end cap to the top of the filter module to ensure a seal between the inner and outer sides of the paper core 210, further reducing the weight of the semi-enclosed end cap structure filter and lowering manufacturing costs.

[0038] In another embodiment, reference Figures 12 to 14 When the cover body of the threaded cover plate 300 tilts downwards on the side near the flange ring 310, and the flange ring 310 shifts further downwards, the top of the mating ring 410 and the bonding surface 420 should remain flush so that after the mating ring 410 and the threaded cover plate 300 are mated together, there is still enough gap between them for dirty oil to flow.

[0039] like Figure 4 and Figure 5 As shown, when there is no means to control the coaxiality of the filter module and the housing 100 after bonding during the assembly process, a constriction 110 is provided at the bottom of the housing 100. The outer diameter of the constriction 110 is smaller than the outer diameter of the open end 101. The bottom end of the filter module is inserted into the constriction 110 of the housing 100, which reduces the gap between the outer periphery of the filter module and the inner wall of the housing 100, thereby improving the coaxiality between the filter module and the housing 100 and further facilitating the insertion of the threaded cover 300 into the open end cover 400 and the housing 100.

[0040] like Figure 6 As shown, when the internal working pressure of the semi-enclosed end cap structure filter is not very high, an inner protrusion 120 is provided at the closed end 102 at the bottom of the housing 100 to offset part of the filling area of ​​the filter paper adhesive 910. Under the premise that the relatively small internal pressure of the semi-enclosed end cap structure filter will not deform the housing 100 and the inner protrusion 120, the amount of filter paper adhesive 910 can be effectively reduced.

[0041] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A filter with a semi-obstructed end cap structure, characterized in that, include: The outer casing (100) is provided with an open end (101) and a closed end (102). The filter module is coaxially placed inside the outer shell (100). The filter module includes a paper core (210). The paper core (210) is configured as a hollow ring structure and is made of V-shaped filter paper connected end to end. The bottom end of the paper core (210) is embedded with the closed end (102) through filter paper glue. The folds of the upper end of the paper core (210) that open inward are sealed with sealing glue. A threaded cover plate (300) includes an integral and coaxially arranged cover plate body and a flanged ring (310). The cover plate body has an oil inlet (301). The flanged ring (310) is located in the inner ring of the cover plate body and is bent downward in a direction parallel to the axial direction of the cover plate body. The inner ring of the flanged ring (310) is provided with a connecting thread (303). The hollow part of the flanged ring (310) is configured as an oil outlet (302). The oil outlet (302) is connected to the hollow part of the filter module. An open end cap (400) includes an integral and coaxially arranged adhesive surface (420) and a mating ring (410). The outer diameter of the adhesive surface (420) is smaller than the outer diameter of the paper core (210). The adhesive surface (420) is sealed to the top of the paper core (210) by the sealing adhesive. The mating ring (410) is located in the inner ring of the adhesive surface (420), and the inner ring of the mating ring (410) is interference-fitted with the outer ring of the flange ring (310). An external sealing module is connected to the cover plate body, and the outer ring of the external sealing module is connected to the opening end (101).

2. The filter with a semi-obstructed end cap structure according to claim 1, characterized in that, The open end cap (400) is made of thermoplastic polyurethane elastomer, and the top of the mating ring (410) is higher than the top of the adhesive surface (420).

3. The filter with a semi-obstructed end cap structure according to claim 2, characterized in that, The open end cap (400) is bonded to the top of the filter module by hot plate welding.

4. The filter with a semi-obstructed end cap structure according to claim 1, characterized in that, The cover plate body is inclined downward on the side near the flange ring (310), and the top of the mating ring (410) is flush with the top of the adhesive surface (420).

5. The filter with a semi-obstructed end cap structure according to claim 1, characterized in that, The outer periphery of the open end cap (400) is provided with a plurality of positioning protrusions at intervals, and the positioning protrusions all abut against the inner wall of the outer shell (100).

6. The filter with a semi-obstructed end cap structure according to claim 1, characterized in that, The bottom of the outer shell (100) is provided with a constriction (110), the outer diameter of the constriction (110) is smaller than the outer diameter of the open end (101), and the bottom end of the filter module is inserted into the constriction (110).

7. The filter with a semi-obstructed end cap structure according to claim 1, characterized in that, The closed end (102) is provided with an inner protrusion (120).

8. The filter with a semi-obstructed end cap structure according to claim 1, characterized in that, The filter module also includes a central tube (220), which is disposed inside the paper core (210) and has a plurality of circumferential openings.

9. The filter with a semi-obstructed end cap structure according to claim 1, characterized in that, The filter paper adhesive at the bottom of the paper core (210) is cured and formed by a mold, and the cured filter paper adhesive is snapped into the inner ring of the closed end (102).

10. The filter with a semi-obstructed end cap structure according to any one of claims 1-9, characterized in that, The outer sealing module includes a sealing ring seat (510) and an outer sealing ring (520). The sealing ring seat (510) is connected to the cover plate body. The sealing ring seat (510) is provided with an outer ring seat (511) and a sealing groove (512). The outer ring seat (511) is connected to the opening end (101). The outer sealing ring (520) is placed in the sealing groove (512).

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