Valve seat filter assembly and throttle valve

Abstract

The utility model provides a valve seat filtering assembly and a throttling valve, and relates to the technical field of throttling. The valve seat filtering assembly is used for being installed in a valve pipe of the throttling valve and comprises a valve seat and a first filtering structure. The valve seat is provided with a fluid channel, an assembly groove is formed in one end of the valve seat in the axial direction of the valve seat, and the assembly groove communicates with the fluid channel. The first filtering structure is installed in the assembling groove along one end of the axial direction of the first filtering structure and is connected with the groove wall of the assembling groove. And the groove wall of the assembling groove can limit the first filtering structure, so that the first filtering structure can be stably mounted. In the assembling process, the valve seat and the first filtering structure are directly assembled, and then the valve seat filtering assembly is integrally installed in the valve pipe. The relative size of the valve seat and the second filtering structure is small, taking operation is easy, the assembling state of the valve seat and the second filtering structure can be observed conveniently in the assembling process, the valve seat and the second filtering structure are protected, and assembling stability is guaranteed.

Description

Technical Field

[0001] The present application relates to the field of throttling technology, and in particular to a valve seat filter assembly and a throttling valve. Background Art

[0002] A tubular throttle valve is a valve that controls the flow of a fluid by changing the throttle cross section or throttle length. Specifically, the throttle valve achieves throttling by the cooperation between the valve core and the valve seat, and a filter structure is provided inside the throttle valve to filter out impurities in the fluid. In the related art, the filter structure is placed inside the tube body, and the tube body of the throttle valve is dotted so that a part of the tube body protrudes into the tube body, and the filter structure is limitedly abutted. However, due to the long tube body, it is impossible to intuitively judge whether the filter structure is limited in place, and it is also impossible to intuitively judge whether the dot processing causes damage to the filter structure. Utility Model Content

[0003] Based on this, it is necessary to provide a valve seat filter assembly and a throttle valve including the valve seat filter assembly, so as to visually observe the installation status of the filter structure when installing the filter structure and ensure stable installation of the filter structure.

[0004] A valve seat filter assembly is used to be installed in a valve tube of a throttle valve, the valve seat filter assembly includes a valve seat and a first filter structure; the valve seat is configured with a fluid channel, and an assembly groove is provided at one end of the valve seat along its own axial direction, and the assembly groove is connected to the fluid channel; one end of the first filter structure along its own axial direction is installed in the assembly groove and connected to the groove wall of the assembly groove.

[0005] It is understandable that the first filter structure is installed in the assembly groove of the valve seat, and the groove wall of the assembly groove can limit the first filter structure, which is conducive to the stable installation of the first filter structure. In the production process, the valve seat and the first filter structure are directly assembled first, and then the valve seat filter assembly is installed in the valve tube as a whole. The valve seat and the second filter structure are relatively small in size, which is easy to carry out the operation, and it is also conducive to observing the assembly status of the two during assembly, so as to protect the valve seat and the second filter structure and ensure the stability of the assembly.

[0006] In one embodiment, the first filter structure is provided with a first tapered portion near the notch of the assembly groove, and along the axis of the first filter structure, the first tapered portion is tapered along the bottom of the assembly groove toward the notch of the assembly groove; the assembly groove is provided with a second tapered portion, and along the axis of the valve seat, the second tapered portion is tapered along the bottom of the assembly groove toward the notch of the assembly groove, and the groove wall at the second tapered portion abuts against the outer peripheral wall of the first tapered portion.

[0007] It can be understood that the second tapered portion can effectively limit the first tapered portion, which is beneficial to promoting assembly stability and reducing the shaking of the first filtering structure during assembly.

[0008] In one embodiment, the first filtering structure includes a first base and a first filtering net connected to the first base, at least a portion of the first base is installed in the assembly groove, and the first base is provided with the first tapered portion.

[0009] It can be understood that the first base is provided to facilitate cooperation with the groove wall of the assembly groove, thereby facilitating the installation of the first filtering structure.

[0010] In one embodiment, the valve seat filter assembly also includes a valve core, which is installed in the fluid channel of the valve seat and can move along its own axial direction; the valve seat is constructed with a flow port and a first limiting portion, the flow port is arranged to penetrate along the radial direction of the valve seat, the flow port can be communicated with the fluid channel, the first limiting portion is formed by protruding inward from the inner wall forming the fluid channel along the radial direction of the valve seat, and along the axial direction of the valve seat, the first limiting portion is located between the flow port and the assembly groove; one end of the valve core close to the first filter structure along its own axial direction can abut against the first limiting portion; the valve core has a throttling hole penetrating along its own axial direction, the throttling hole can be communicated with the fluid channel, and the inner diameter of the flow port is larger than the inner diameter of the throttling hole.

[0011] It can be understood that the provision of the first limit portion facilitates the valve core to abut against the inside of the valve seat. When the valve core abuts against the first limit portion, the fluid cannot flow from the flow port into the fluid channel and then flow out of the assembly groove. The fluid can only flow from the throttling hole of the valve core into the assembly groove, thereby achieving a throttling effect.

[0012] In one embodiment, the valve seat is provided with a second limiting portion, and the second limiting portion is arranged at an end of the valve seat away from the assembly groove. Along the axial direction of the valve seat, the valve core is located between the second limiting portion and the first limiting portion, and the second limiting portion can abut against an end of the valve core away from the first limiting portion.

[0013] It can be understood that the setting of the second limiting portion cooperates with the first limiting portion to jointly limit the moving space of the valve core, so that the valve core can be directly assembled in the valve seat, which is convenient for observing the assembly status of the valve core in the valve seat. The valve core, the valve seat and the first filter structure form a whole and are installed in the throttle valve as a whole, which is easy to assemble.

[0014] A throttle valve comprises a valve tube and the above-mentioned valve seat filter assembly, wherein the valve tube is provided with a lumen axially penetrating the valve tube; and the valve seat filter assembly is installed in the lumen.

[0015] It is understandable that, with such an arrangement, the valve seat and the first filter structure can be first installed to form a valve seat filter assembly and then installed as a whole into the tube cavity of the throttle valve. This is easy to operate and facilitates intuitively obtaining the assembly status of the first filter structure outside the valve tube, thereby promoting the assembly stability of the first filter structure and reducing the number of assembly steps of the first filter structure in the valve tube.

[0016] In one embodiment, the valve seat is provided with a limiting groove, and the inner wall of the valve tube is constructed with a first limiting protrusion protruding in the tube cavity along its own radial direction, and the first limiting protrusion is at least partially located in the limiting groove and abuts against the groove wall of the limiting groove.

[0017] It can be understood that the cooperation between the limiting groove of the valve seat and the first limiting protrusion of the valve pipe facilitates the stable assembly of the valve seat filter assembly.

[0018] In one embodiment, two valve seat filter assemblies are provided, and the two valve seat filter assemblies are arranged axially of the valve tube at intervals, and the first filter structures in the two valve seat filter assemblies are arranged opposite to each other.

[0019] It can be understood that two valve seat filter assemblies are provided to facilitate bidirectional throttling.

[0020] In one embodiment, the valve seat filter assembly is provided with one; the throttle valve also includes a second filter structure, the second filter structure is installed in the valve tube and is spaced apart from the valve seat filter assembly, and the second filter structure and the first filter structure are arranged opposite to each other along the axial direction of the valve tube.

[0021] It is understandable that a valve seat filter assembly is provided to realize one-way throttling, and cooperates with the second filter structure to realize two-way filtering.

[0022] In one embodiment, the inner wall of the valve tube is constructed with a second limiting protrusion protruding in the tube cavity along its own radial direction, the second limiting protrusion is spaced apart from the first limiting protrusion, and the second limiting protrusion abuts against the second filtering structure and limits the second filtering structure.

[0023] It can be understood that the second limiting protrusion is provided to limit the installation of the second filtering structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A cross-sectional view of a valve seat filter assembly provided for this application;

[0026] Figure 2 A cross-sectional view of an embodiment of a throttle valve provided in the present application;

[0027] Figure 3 A cross-sectional view of another embodiment of a throttle valve provided in the present application.

[0028] Figure numerals: 100, throttle valve; 10, valve seat filter assembly; 11, valve seat; 101, fluid channel; 1011, first limiting portion; 1012, second limiting portion; 102, assembly groove; 1021, second tapered portion; 103, limiting groove; 104, flow port; 12, first filter structure; 121, first base; 1211, first tapered portion; 122, first filter net; 13, valve core; 131, throttle hole; 20, second filter structure; 30, valve tube; 301, tube cavity; 31, first limiting protrusion; 32, second limiting protrusion. 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] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the specification of this application are for illustrative purposes only and do not represent the only implementation method.

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

[0032] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first feature is directly in contact with the second feature, or the first feature and the second feature are indirectly in contact through an intermediate medium. Moreover, a first feature being “above”, “above” or “above” a 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. A first feature being “below”, “below” or “below” a 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.

[0033] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more related listed items.

[0034] See also Figures 1 to 3 The present application provides a valve seat filter assembly 10, which is used to be installed in a valve tube 30 of a throttle valve 100. The valve seat filter assembly 10 includes a valve seat 11 and a first filter structure 12; the valve seat 11 is configured with a fluid channel 101, and an assembly groove 102 is provided at one end of the valve seat 11 along its own axial direction, and the assembly groove 102 is connected to the fluid channel 101; the first filter structure 12 is installed in the assembly groove 102 at one end along its own axial direction, and is connected to the groove wall of the assembly groove 102.

[0035] In this way, the fluid can pass through the valve seat 11 from the fluid channel 101 and pass through the first filter structure 12. The first filter structure 12 can filter out impurities in the fluid and reduce the impact of impurities on the valve seat 11 and other parts. The valve seat 11 is provided with an assembly groove 102 to install the first filter structure 12, so that the valve seat 11 and the first filter structure 12 are formed into one body, that is, they can be installed as a whole in the valve tube 30 of the throttle valve 100, and only need to be assembled with the valve tube 30 once, which has little impact on the structural strength of the valve tube 30. At the same time, when the valve seat 11 and the first filter structure 12 are assembled outside the valve tube 30, the stability of the first filter structure 12 relative to the valve seat 11 can be intuitively observed, which is conducive to protecting the valve seat 11 and the first filter structure 12. Further, during processing, the outer diameter of the first filter structure 12 is smaller than the inner diameter of the valve tube 30 and equal to the inner diameter of the assembly groove 102, which correspondingly reduces the size of the first filter structure 12, thereby reducing consumables and helping to reduce costs.

[0036] like Figure 1As shown, in an optional embodiment, the first filter structure 12 is provided with a first tapered portion 1211 at the notch of the assembly groove 102, and along the axis of the first filter structure 12, the first tapered portion 1211 is tapered along the bottom of the assembly groove 102 toward the notch of the assembly groove 102; the assembly groove 102 is provided with a second tapered portion 1021, and along the axis of the valve seat 11, the second tapered portion 1021 is tapered along the bottom of the assembly groove 102 toward the notch of the assembly groove 102, and the groove wall at the second tapered portion 1021 abuts against the outer peripheral wall of the first tapered portion 1211.

[0037] In this way, the groove wall where the second tapered portion 1021 is located forms an inclined slope, which cooperates with the inclined outer surface of the first tapered portion 1211. The second tapered portion 1021 has a limiting effect on the first tapered portion 1211 along the axial and radial directions of the valve seat 11, reducing the shaking of the first filter structure 12 during assembly, and facilitating the determination of the assembly depth of the first filter structure 12 in the assembly groove 102, thereby facilitating the positioning of the first filter structure 12. In actual operation, the first filter structure 12 is first installed in the assembly groove 102, and then the valve seat 11 is processed to form the second tapered portion 1021.

[0038] It should be noted that the first filter structure 12 and the valve seat 11 may be connected by welding, riveting, bonding, clamping, threaded connection, etc., which are not specifically limited here and are only used as examples.

[0039] like Figure 1 As shown, in a specific embodiment, the first filter structure 12 includes a first base 121 and a first filter screen 122 connected to the first base 121. At least part of the first base 121 is installed in the assembly groove 102, and the first base 121 is provided with a first tapered portion 1211. In this way, the first base 121 can fix the first filter screen 122, and can realize the installation of the first filter structure 12 relative to the valve seat 11 by connecting with the groove wall of the assembly groove 102, which is easy to operate. The first filter screen 122 is fixed to the valve seat 11 through the first base 121 to facilitate filtering of impurities.

[0040] like Figure 1As shown, in a further embodiment, the valve seat filter assembly 10 also includes a valve core 13, which is installed in the fluid channel 101 of the valve seat 11 and can move along its own axial direction; the valve seat 11 is constructed with a flow port 104 and a first limiting portion 1011, the flow port 104 is arranged to penetrate along the radial direction of the valve seat 11, the flow port 104 can be communicated with the fluid channel 101, the first limiting portion 1011 is protruded inwardly from the inner wall of the valve seat 11 that forms the fluid channel 101 along the radial direction of the valve seat 11, and along the axial direction of the valve seat 11, the first limiting portion 1011 is located between the flow port 104 and the assembly groove 102; one end of the valve core 13 that is close to the first filter structure 12 along its own axial direction can abut against the first limiting portion 1011; the valve core 13 has a throttling hole 131 that penetrates along its own axial direction, the throttling hole 131 can be communicated with the fluid channel 101, and the inner diameter of the flow port 104 is larger than the inner diameter of the throttling hole 131.

[0041] In this way, the valve core 13 can switch the throttling state by moving along its own axial direction. Specifically, when the fluid pushes the valve core 13 to abut against the first limit portion 1011, the first limit portion 1011 limits the axial movement of the valve core 13, and the outer peripheral wall of the valve core 13 forms a hard seal with the first limit portion 1011. The side wall of the valve core 13 blocks the flow port 104, and the fluid cannot flow between the outer peripheral wall of the valve core 13 and the inner wall of the valve seat 11, so the fluid can only flow out from the throttling hole 131 of the valve core 13. The inner diameter of the throttling hole 131 is small to achieve a throttling effect. After the fluid flows out of the throttling hole 131, it is filtered and output by the first filter structure 12. When the fluid pushes the valve core 13 away from the first limit portion 1011, the flow port 104 is not blocked by the side wall of the valve core 13, and the fluid can flow out from the flow port 104, thereby canceling the throttling.

[0042] like Figure 1 As shown, in a further embodiment, the valve seat 11 is provided with a second limiting portion 1012, and the second limiting portion 1012 is arranged at one end of the valve seat 11 away from the assembly groove 102. Along the axial direction of the valve seat 11, the valve core 13 is located between the second limiting portion 1012 and the first limiting portion 1011, and the second limiting portion 1012 can abut against one end of the valve core 13 away from the first limiting portion 1011.

[0043] In this way, the second limiting portion 1012 can limit the axial movement of the valve core 13 away from one end of the first limiting portion 1011, so that the valve core 13 is installed in the valve seat 11, and then the valve core 13, the valve seat 11 and the first filter structure 12 form a whole. When assembling the throttle valve 100, it is not necessary to sequentially install the valve core 13, the valve seat 11 and the first filter structure 12 into the valve tube 30, and the assembly is more convenient. When assembling outside the valve tube 30, the assembly status of the valve core 13 relative to the valve seat 11 can be observed, which is conducive to protecting the valve core 13.

[0044] like Figure 2 and Figure 3 As shown, the present application also provides a throttle valve 100, including a valve tube 30 and the above-mentioned valve seat filter assembly 10, the valve tube 30 is provided with a tube cavity 301 axially passing through itself; the valve seat filter assembly 10 is installed in the tube cavity 301. Since the valve tube 30 is relatively long, assembly is inconvenient. This arrangement does not require the valve seat 11 and the filter net to be assembled into the valve tube 30 in turn, which is beneficial to saving assembly time and is also convenient for visually observing the assembly status of the first filter structure 12 outside the valve tube 30, thereby reducing damage to the first filter structure 12 during the assembly process.

[0045] In a specific embodiment, the valve seat 11 is provided with a limiting groove 103, and the inner wall of the valve tube 30 is constructed with a first limiting protrusion 31 protruding along its own radial direction in the tube cavity 301, and the first limiting protrusion 31 is at least partially located in the limiting groove 103 and abuts against the groove wall of the limiting groove 103.

[0046] In this way, the first limiting protrusion 31 and the groove wall of the limiting groove 103 can limit each other along the axial direction of the valve seat 11, thereby limiting the displacement of the valve seat 11 along the axial direction of the valve tube 30, and promoting the stability of the assembly of the valve seat filter assembly 10. In the actual operation process, the valve seat filter assembly 10 is first installed at the position required by the working condition, and then the valve tube 30 is dotted to form the first limiting protrusion 31. In this way, since the valve seat filter assembly 10 is assembled as a whole, there is no need to dot the valve tube 30 again at the corresponding position of the first filter structure 12, which reduces the impact on the structure of the valve tube 30.

[0047] like Figure 3 As shown, in some embodiments, two valve seat filter assemblies 10 are provided, and the two valve seat filter assemblies 10 are arranged axially and spaced apart from each other along the valve tube 30, and the first filter structures 12 in the two valve seat filter assemblies 10 are arranged back to back. In this way, the fluid flowing in from either side of the valve tube 30 can obtain the throttling and filtering effects of the valve seat filter assembly 10, which is conducive to realizing two-way throttling and filtering.

[0048] like Figure 2 As shown, in other embodiments, the valve seat filter assembly 10 is provided with one; the throttle valve 100 also includes a second filter structure 20, which is installed in the valve tube 30 and spaced apart from the valve seat filter assembly 10, and the second filter structure 20 and the first filter structure 12 are arranged opposite to each other along the axial direction of the valve tube 30. At this time, when the fluid flows from the first filter structure 12 to the second filter structure 20, throttling can be achieved, while when the fluid flows from the second filter structure 20 to the first filter structure 12, throttling is not performed, that is, one-way throttling is achieved.

[0049] In a specific embodiment, the inner wall of the valve tube 30 is constructed with a second limiting protrusion 32 which is radially protruded in the tube cavity 301. The second limiting protrusion 32 is spaced apart from the first limiting protrusion 31. The second limiting protrusion 32 abuts against the second filter structure 20 and limits the second filter structure 20 to limit the radial movement of the second filter structure 20 along the valve tube 30, thereby realizing the assembly of the second filter structure 20.

[0050] 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.

[0051] 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 understood 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 scope of patent protection of the present application shall be subject to the attached claims.

Claims

1. A valve seat filter assembly, used for installation in a valve tube of a throttle valve, characterized in that: The valve seat filter assembly comprises: A valve seat (11) is provided with a fluid channel (101); an assembly groove (102) is provided at one end of the valve seat (11) along its axial direction, and the assembly groove (102) is communicated with the fluid channel (101); The first filtering structure (12) is installed in the assembly groove (102) at one end along its axial direction and is connected to the groove wall of the assembly groove (102).

2. The valve seat filter assembly according to claim 1, characterized in that: The first filtering structure (12) is provided with a first tapered portion (1211) near the notch of the assembly groove (102); along the axis of the first filtering structure (12), the first tapered portion (1211) is arranged to be tapered along the bottom of the assembly groove (102) towards the notch of the assembly groove (102); The groove wall of the assembly groove (102) is provided with a second tapered portion (1021), and along the axis of the valve seat (11), the second tapered portion (1021) tapers along the bottom of the assembly groove (102) toward the groove opening of the assembly groove (102), and the groove wall at the second tapered portion (1021) abuts against the outer peripheral wall of the first tapered portion (1211).

3. The valve seat filter assembly according to claim 2, characterized in that: The first filtering structure (12) comprises a first base (121) and a first filtering net (122) connected to the first base (121); at least a portion of the first base (121) is installed in the assembly groove (102); and the first base (121) is provided with the first tapered portion (1211).

4. The valve seat filter assembly according to claim 1, characterized in that: The valve seat filter assembly further comprises a valve core (13), the valve core (13) being installed in the fluid channel (101) of the valve seat (11) and being able to move along its own axial direction; the valve seat (11) is constructed with a flow port (104) and a first limiting portion (1011), the flow port (104) being arranged to penetrate radially along the valve seat (11), the flow port (104) being able to communicate with the fluid channel (101), the first limiting portion (1011) being formed by protruding inwardly from an inner wall forming the fluid channel (101) along the radial direction of the valve seat (11); along the axial direction of the valve seat (11), the first limiting portion (1011) is located between the flow port (104) and the assembly groove (102); One end of the valve core (13) close to the first filter structure (12) along its own axial direction can abut against the first limiting portion (1011); the valve core (13) has a throttling hole (131) penetrating along its own axial direction, and the throttling hole (131) can be connected to the fluid channel (101); the inner diameter of the flow port (104) is larger than the inner diameter of the throttling hole (131).

5. The valve seat filter assembly according to claim 4, characterized in that: The valve seat (11) is provided with a second limiting portion (1012), and the second limiting portion (1012) is arranged at an end of the valve seat (11) away from the assembly groove (102), and along the axial direction of the valve seat (11), the valve core (13) is located between the first limiting portion (1011) and the second limiting portion (1012), and the second limiting portion (1012) can abut against an end of the valve core (13) away from the first limiting portion (1011).

6. A throttle valve, characterized in that: include: The valve tube (30) is provided with a lumen (301) which penetrates the valve tube axially; The valve seat filter assembly according to any one of claims 1 to 5 is installed in the tube cavity (301).

7. The throttle valve according to claim 6, characterized in that The valve seat (11) is provided with a limiting groove (103), and the inner wall of the valve tube (30) is configured with a first limiting protrusion (31) which is radially protruding in the tube cavity (301), and the first limiting protrusion (31) is at least partially located in the limiting groove (103) and abuts against the groove wall of the limiting groove (103).

8. The throttle valve according to claim 7, characterized in that Two valve seat filter assemblies are provided, and the two valve seat filter assemblies are arranged at intervals along the axial direction of the valve tube (30), and the first filter structures (12) in the two valve seat filter assemblies are arranged opposite to each other.

9. The throttle valve according to claim 7, characterized in that: The valve seat filter assembly is provided with a; The throttle valve further comprises a second filter structure (20), wherein the second filter structure (20) is installed in the valve tube (30) and is spaced apart from the valve seat filter assembly, and the second filter structure (20) and the first filter structure (12) are axially disposed opposite to each other along the valve tube (30).

10. The throttle valve according to claim 9, characterized in that The inner wall of the valve tube (30) is constructed with a second limiting protrusion (32) which is radially protruding inside the tube cavity (301), the second limiting protrusion (32) being spaced apart from the first limiting protrusion (31), and the second limiting protrusion (32) abuts against the second filtering structure (20) and limits the second filtering structure (20).

Images