Charging valve and expansion tank

Abstract

The utility model provides a filling valve and an expansion tank, the filling valve comprises a valve seat, a valve cover and a valve needle assembly, the valve needle assembly is arranged in the valve seat and is provided with a valve port capable of being opened and closed, and the periphery of the valve needle assembly is in sealing fit with the inner wall of a cavity of the valve seat; the valve cover is detachably buckled at one end of the valve seat, and under the condition that the valve cover is installed on the valve seat, the inner wall of a cavity of the valve cover is matched with the periphery of the valve seat in a sealing mode. By the adoption of the scheme, when the filling valve is not used, gas leakage is prevented through double sealing of the valve seat, the valve needle assembly and the valve deck, gas leakage can be effectively prevented through double sealing when the filling valve is not used, and the phenomenon that gas leakage is caused when the filling valve adopts single sealing (sealing fit between the valve seat and the valve needle assembly) is avoided. And if the sealing fails, the air leakage of the filling valve is caused, so that the self-sealing effect of the filling valve is improved, air leakage is avoided while the filling valve can cope with various complex environments, and the reliability of the filling valve and the applicability to different application environments are improved.

Description

Technical Field

[0001] This utility model relates to the field of expansion tank technology, and more specifically, to a filling valve and an expansion tank. Background Technology

[0002] The main function of the expansion tank is to absorb the expansion volume of the system and stabilize the system pressure. The rubber liner inside the expansion tank relies on the pre-filling pressure between the rubber liner and the tank body to balance the water pressure. If the gas leaks out, the rubber liner will rupture after repeated friction with the tank body.

[0003] Expansion tank filling valves typically use sealing rings or other sealing components to ensure a tight seal and prevent leakage. When the filling valve is not in use, the valve cover is fastened to the opening on the side of the valve seat away from the tank body to seal the opening. However, existing filling valves are usually single seals, and the valve cover only serves to stop the gas flow and cannot provide auxiliary sealing. If the seal of the filling valve itself fails, leaked gas will still leak out from the gap between the valve cover and the valve seat, ultimately leading to damage or failure of the expansion tank. Utility Model Content

[0004] This invention provides a filling valve and an expansion tank to improve the sealing effect of the filling valve when it is not in use.

[0005] To achieve the above objectives, according to one aspect of the present invention, a filling valve is provided, comprising a valve seat, a valve cover, and a valve needle assembly. The valve needle assembly is disposed within the valve seat and has an openable and closable valve port. The outer periphery of the valve needle assembly is in sealing fit with the inner wall of the cavity of the valve seat. The valve cover is detachably fastened to one end of the valve seat, and when the valve cover is installed on the valve seat, the inner wall of the cavity of the valve cover is in sealing fit with the outer periphery of the valve seat.

[0006] Furthermore, the valve cover and valve seat can be separably abutted together, forming an annular sealing area around the cavity of the valve needle assembly when they abut together.

[0007] Furthermore, the inner wall of the valve cover cavity has internal threads, and at least a portion of the outer periphery of the valve seat has external threads, and the valve cover and valve seat are threadedly connected; the bottom wall of the valve cover cavity abuts against the end of the valve seat to form an annular sealing area; or, the inner wall of the valve cover cavity abuts against the outer periphery of the valve seat to form an annular sealing area.

[0008] Furthermore, the outer periphery of the valve seat has a first annular stop step or a first annular stop surface that is inclined relative to the axis of the valve seat, and one side of the cavity opening of the valve cover abuts against the first annular stop step or the first annular stop surface to form an annular sealing area.

[0009] Furthermore, one side of the cavity opening of the valve cover has a second annular stop step or a second annular stop surface that is inclined relative to the axis of the valve seat; the second annular stop step abuts against the first annular stop step or the first annular stop surface to form an annular sealing area; or, the second annular stop surface abuts against the first annular stop step or the first annular stop surface to form an annular sealing area.

[0010] Furthermore, the valve seat includes a first mating section, a transition section, and a second mating section connected in sequence. The outer diameter of the second mating section is larger than that of the first mating section. The outer diameter of at least part of the transition section gradually decreases in the direction of the second mating section toward the first mating section and forms a first annular stop surface. The valve cover is detachably fastened to one end of the first mating section away from the second mating section. One side of the cavity opening of the valve cover abuts against the first annular stop surface on the transition section to form an annular sealing area.

[0011] Furthermore, the valve cover includes a transition cylinder section, an annular abutment section, and a limiting section connected coaxially in sequence. The annular abutment section is located at the opening of the transition cylinder section, and the limiting section is located at the opening of the transition cylinder section. The inner diameter of the annular abutment section is smaller than the inner diameter of the limiting section but larger than the inner diameter of the transition cylinder section. The annular abutment section forms a second annular stop step and has an abutment tip extending circumferentially thereon. The abutment tip abuts against the first annular stop surface to form an annular sealing area, which is an annular sealing line.

[0012] Furthermore, the filling valve also includes a first annular seal, and the inner wall of the valve cover cavity is sealed to the outer periphery of the valve seat through the first annular seal.

[0013] Furthermore, the filling valve also includes a second annular seal disposed on the outer periphery of the valve needle assembly, and the valve needle assembly is sealed to the inner wall of the valve seat cavity through the second annular seal.

[0014] Furthermore, the valve needle assembly includes a valve housing and a valve needle body movably disposed within the valve housing. The valve housing is disposed within a valve seat and seals against the inner wall of the valve seat. The valve port is located at the end of the valve housing, and the end of the valve needle body has a sealing element to block or open the valve port.

[0015] Furthermore, at least a portion of the outer periphery of the valve body has external threads, and the inner wall of the valve seat cavity has corresponding internal threads, thus the valve body and valve seat are threadedly connected.

[0016] According to another aspect of the present invention, an expansion tank is provided, the expansion tank including a tank body, a protective shell and the aforementioned filling valve, the end of the tank body is an outwardly convex arc surface and has an air inlet, a first limiting structure is provided at the air inlet, a second limiting structure is provided at the end of the valve seat of the filling valve away from the valve cover, the valve seat of the filling valve is installed at the air inlet and the first limiting structure and the second limiting structure are mutually limiting and cooperating, and the protective shell is fastened to the filling valve and abuts against the end of the tank body.

[0017] The present invention provides a filling valve, which includes a valve seat, a valve cover, and a valve needle assembly. The valve needle assembly is disposed inside the valve seat and has an openable and closable valve port. The outer periphery of the valve needle assembly is sealed to the inner wall of the valve seat cavity. The valve cover is detachably fastened to one end of the valve seat. When the valve cover is installed on the valve seat, the inner wall of the valve cover cavity is sealed to the outer periphery of the valve seat.

[0018] With this design, when the filling valve is not in use, the valve cover is mounted on the valve seat. The filling valve prevents gas leakage through a double seal between the valve seat, the valve needle assembly, and the valve cover. When the filling valve needs to be used, the operator removes the valve cover. At this time, the filling valve prevents gas leakage during the filling process through the seal between the valve seat and the valve needle assembly. This design, through double sealing, effectively prevents gas leakage when the filling valve is not in use, avoiding the leakage that can occur if the single seal (the sealing fit between the valve seat and the valve needle assembly) fails. This improves the self-sealing effect of the filling valve, enabling it to withstand various complex environments without leakage, thus enhancing the reliability and applicability of the filling valve to different application environments. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0020] Figure 1 A schematic diagram of the structure of the expansion tank provided in an embodiment of the present invention is shown;

[0021] Figure 2 It shows Figure 1 A sectional view;

[0022] Figure 3 It shows Figure 2 A magnified view of position A in the middle;

[0023] Figure 4 It shows Figure 3 A magnified cross-sectional view from another perspective.

[0024] The above figures include the following reference numerals:

[0025] 10. Filling valve; 101. Annular sealing area;

[0026] 11. Valve seat; 111. First mating section; 112. Transition section; 1121. First annular stop surface; 113. Second mating section; 1131. Second limiting structure;

[0027] 12. Valve cover; 121. Transition cylinder section; 122. Annular abutment section; 123. Limiting section; 1201. Second annular stop step;

[0028] 13. Valve needle assembly; 1301. Valve port; 1302. Air inlet; 131. Valve housing; 132. Valve needle body; 133. Sealing component;

[0029] 14. Annular seal;

[0030] 20. Tank body; 21. First limiting structure;

[0031] 30. Protective casing. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0033] like Figures 1 to 4 As shown, this utility model provides a filling valve 10, which includes a valve seat 11, a valve cover 12, and a valve needle assembly 13. The valve needle assembly 13 is disposed inside the valve seat 11 and has an openable and closable valve port 1301. The outer periphery of the valve needle assembly 13 is sealed to the inner wall of the cavity of the valve seat 11. The valve cover 12 is detachably fastened to one end of the valve seat 11. When the valve cover 12 is installed on the valve seat 11, the inner wall of the cavity of the valve cover 12 is sealed to the outer periphery of the valve seat 11.

[0034] In this embodiment, when the filling valve 10 is not in use, the valve cover 12 is installed on the valve seat 11. The filling valve 10 prevents gas leakage through the double seal of the valve seat 11, the valve needle assembly 13, and the valve cover 12. When the filling valve 10 needs to be used, the operator removes the valve cover 12. At this time, the filling valve 10 prevents gas leakage during the filling process through the seal of the valve seat 11 and the valve needle assembly 13. This configuration, through double sealing, effectively prevents gas leakage when the filling valve 10 is not in use. It avoids the situation where the filling valve 10 leaks if the single seal (the sealing fit between the valve seat 11 and the valve needle assembly 13) fails, which would be a problem when the filling valve 10 uses a single seal. This improves the self-sealing effect of the filling valve 10, enabling it to cope with various complex environments without leakage, thus improving the reliability of the filling valve 10 and its applicability to different application environments.

[0035] In this embodiment, the valve cover 12 and the valve seat 11 are detachably abutted together, forming an annular sealing area 101 around the cavity of the valve needle assembly 13. A hard seal is used between the valve cover 12 and the valve seat 11 in this embodiment, which provides a more reliable seal compared to a soft seal. This enhances the sealing performance of the filling valve 10, ensuring that gas will not leak from the connection between the valve cover and the valve seat under high pressure or other conditions, thereby improving the service life of the filling valve 10 and the overall stability of the system.

[0036] In this embodiment, the inner wall of the cavity of the valve cover 12 has internal threads, and at least a portion of the outer periphery of the valve seat 11 has external threads, with the valve cover 12 and the valve seat 11 being threadedly connected. The bottom wall of the cavity of the valve cover 12 abuts against the end of the valve seat 11 to form an annular sealing region 101; or, the inner wall of the cavity of the valve cover 12 abuts against the outer periphery of the valve seat 11 to form an annular sealing region 101. This arrangement facilitates the disassembly and assembly of the valve cover 12 and the tight abutment between the valve cover 12 and the valve seat 11, ensuring the reliability of the annular sealing region 101 formation and the sealing effect between the valve cover 12 and the valve seat 11.

[0037] Optionally, the outer periphery of the valve seat 11 has a first annular stop step or a first annular stop surface 1121 that is inclined relative to the axis of the valve seat 11, and one side of the cavity opening of the valve cover 12 abuts against the first annular stop step or the first annular stop surface 1121 to form an annular sealing area 101.

[0038] This configuration enables the valve cover 12 and valve seat 11 to abut and seal in the axial direction, which helps to limit the sealing position and ensure the reliability of the abutment seal.

[0039] Specifically, one side of the cavity opening of the valve cover 12 has a second annular stop step 1201 or a second annular stop surface that is inclined relative to the axis of the valve seat 11; the second annular stop step 1201 abuts against the first annular stop step or the first annular stop surface 1121 to form an annular sealing area 101; or, the second annular stop surface abuts against the first annular stop step or the first annular stop surface 1121 to form an annular sealing area 101.

[0040] This configuration further ensures the axial sealing between the valve cover 12 and the valve seat 11, as well as the reliability of the sealing. It also facilitates the corresponding installation of the valve cover 12 and the valve seat 11 (i.e., the corresponding installation of the first annular stop step or the first annular stop surface 1121 with the second annular stop step 1201 or the second annular stop surface), ensuring both the installation effect and the sealing effect.

[0041] Specifically, such as Figure 3 and Figure 4As shown, the valve seat 11 includes a first mating section 111, a transition section 112, and a second mating section 113 connected sequentially. The outer diameter of the second mating section 113 is larger than the outer diameter of the first mating section 111. At least part of the outer diameter of the transition section 112 gradually decreases in the direction from the second mating section 113 toward the first mating section 111, forming a first annular stop surface 1121. The valve cover 12 is detachably fastened to the end of the first mating section 111 opposite to the second mating section 113. One side of the cavity opening of the valve cover 12 abuts against the first annular stop surface 1121 on the transition section 112 to form an annular sealing area 101. This arrangement not only ensures and improves the sealing effect but also facilitates the forming of the first annular stop surface 1121 and simplifies the assembly process of the filling valve 10, thereby reducing processing and maintenance costs.

[0042] Furthermore, such as Figure 3 and Figure 4 As shown, the valve cover 12 includes a transition cylinder section 121, an annular abutment section 122, and a limiting section 123 connected coaxially in sequence. The annular abutment section 122 is located at the opening of the transition cylinder section 121, and the limiting section 123 is located at the opening of the transition cylinder section 121. The inner diameter of the annular abutment section 122 is smaller than the inner diameter of the limiting section 123 but larger than the inner diameter of the transition cylinder section 121. The annular abutment section 122 forms a second annular stop step 1201 and has an abutment tip extending circumferentially thereon. The abutment tip abuts against the first annular stop surface 1121 to form an annular sealing area 101. The annular sealing area 101 is an annular sealing line.

[0043] In this embodiment, the inner diameter of the cavity of the adapter section 121 is adapted to the outer diameter of the first mating section 111. The inner wall of the cavity of the adapter section 121 has an internal thread, and the outer periphery of the first mating section 111 has an external thread. The transition section 112 is divided into a variable diameter section and a constant diameter section. The constant diameter section is connected to the second mating section 113, and the variable diameter section is connected to the first mating section 111. The radial dimension of the variable diameter section gradually increases in the direction from the first mating section 111 to the second mating section 113 and forms a first annular stop surface 1121. The outer diameter of the constant diameter section is adapted to the inner diameter of the limiting section 123. When installing the valve cover 12, it is snapped onto the top of the valve seat 11 and gradually screwed in until the abutting sharp corner abuts against the first annular stop surface 1121 and cannot be screwed in any further and is tightened. The limiting section 123 and the constant diameter section of the transition section 112 limit each other, thus completing the installation of the valve cover 12. This configuration, through the tight contact between the abutting corner and the first annular stop surface 1121, forms a high-strength annular sealing line, effectively preventing gas leakage. Preferably, the structure at the junction of the second annular stop step 1201 and the first annular stop surface 1121 can be made of metal or similar materials, which is beneficial for further improving the high-temperature and high-pressure resistance of the sealing position.

[0044] It is understood that the seal between the valve cover 12 and the valve seat 11 may not be achieved through the hard contact seal described above. Optionally, in other embodiments not shown in the figure, the filling valve 10 further includes a first annular seal, and the inner wall of the cavity of the valve cover 12 is sealed to the outer periphery of the valve seat 11 through the first annular seal.

[0045] like Figure 3 and Figure 4 As shown, the filling valve 10 also includes a second annular seal 14 disposed on the outer periphery of the valve needle assembly 13. The valve needle assembly 13 is sealed to the inner wall of the cavity of the valve seat 11 through the second annular seal 14. The second annular seal 14 has a certain degree of flexibility, that is, the valve needle assembly 13 and the valve seat 11 are softly sealed through the second annular seal 14, ensuring the reliability of the seal between the valve needle assembly 13 and the valve seat 11.

[0046] Specifically, the valve needle assembly 13 includes a valve housing 131 and a valve needle body 132 movably disposed within the valve housing 131. The valve housing 131 is disposed within the valve seat 11 and seals against the inner wall of the valve seat 11. The valve port 1301 is located at the end of the valve housing 131. The end of the valve needle body 132 has a sealing member 133 to block or open the valve port 1301.

[0047] In this embodiment, the valve housing 131 of the valve needle assembly 13 has an injection port 1302 at its top. When the charging valve 10 needs to be used, the valve cover 12 can be removed first, and then the valve needle body 132 and the sealing member 133 can be pressed down to open the valve port 1301. Gas is injected into the valve from the top opening of the valve seat 11, and the gas enters the valve housing 131 through the injection port 1302 and flows out from the valve port 1301. This design allows the valve needle assembly 13 to precisely control the charging and releasing of gas, making it suitable for applications requiring precise gas control.

[0048] The valve housing 131 has external threads on at least a portion of its outer periphery, and the valve seat 11 has corresponding internal threads on its inner wall, forming a threaded connection between the valve housing 131 and the valve seat 11. This design facilitates the installation of the valve needle assembly 13 within the valve seat 11 and also ensures the press-fitting of the second annular seal 14, guaranteeing a tight seal.

[0049] Another embodiment of this utility model provides an expansion tank, which includes a tank body 20, a protective shell 30, and the aforementioned filling valve 10. The end of the tank body 20 is a convex arc surface and has an air inlet. A first limiting structure 21 is provided at the air inlet. A second limiting structure 1131 is provided at the end of the valve seat 11 of the filling valve 10 away from the valve cover 12. The valve seat 11 of the filling valve 10 is installed at the air inlet and the first limiting structure 21 and the second limiting structure 1131 are mutually limiting and cooperating. The protective shell 30 is fastened to the filling valve 10 and abuts against the end of the tank body 20.

[0050] In this embodiment, the cooperation of the first limiting structure 21 and the second limiting structure 1131 facilitates the positioning and installation of the filling valve 10 on the tank body 20. The protective shell 30 protects the filling valve 10 when not in use, preventing damage from external environmental influences. Furthermore, in this embodiment, the filling valve 10 is positioned as a convex arc surface. Compared to the traditional concave arc surface, the convex arc surface is more effective in preventing the expansion tank from deforming due to excessive pressure, thereby effectively ensuring the service life and quality of the expansion tank.

[0051] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0052] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0053] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0054] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0055] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0056] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A filling valve, characterized in that, The filling valve includes a valve seat (11), a valve cover (12), and a valve needle assembly (13). The valve needle assembly (13) is disposed inside the valve seat (11) and has an openable and closable valve port (1301). The outer periphery of the valve needle assembly (13) is sealed to the inner wall of the cavity of the valve seat (11). The valve cover (12) is detachably fastened to one end of the valve seat (11). When the valve cover (12) is installed on the valve seat (11), the inner wall of the cavity of the valve cover (12) is sealed to the outer periphery of the valve seat (11).

2. The filling valve according to claim 1, characterized in that, The valve cover (12) and the valve seat (11) are detachably abutted together, and when they abut each other, they form an annular sealing area (101) around the cavity of the valve needle assembly (13).

3. The filling valve according to claim 2, characterized in that, The inner wall of the cavity of the valve cover (12) has internal threads, and at least a portion of the outer periphery of the valve seat (11) has external threads. The valve cover (12) and the valve seat (11) are threaded together. The bottom wall of the cavity of the valve cover (12) abuts against the end of the valve seat (11) to form the annular sealing area (101); or, the inner wall of the cavity of the valve cover (12) abuts against the outer periphery of the valve seat (11) to form the annular sealing area (101).

4. The filling valve according to claim 1, characterized in that, The outer periphery of the valve seat (11) has a first annular stop step or a first annular stop surface (1121) that is inclined relative to the axis of the valve seat (11). One side of the cavity opening of the valve cover (12) abuts against the first annular stop step or the first annular stop surface (1121) to form an annular sealing area (101).

5. The filling valve according to claim 4, characterized in that, The valve cover (12) has a second annular stop step (1201) or a second annular stop surface that is inclined relative to the axis of the valve seat (11) on one side of the cavity opening. The second annular stop step (1201) abuts against the first annular stop step or the first annular stop surface (1121) to form the annular sealing area (101); Alternatively, the second annular stop surface abuts against the first annular stop step or the first annular stop surface (1121) to form the annular sealing area (101).

6. The filling valve according to claim 4, characterized in that, The valve seat (11) includes a first mating section (111), a transition section (112), and a second mating section (113) connected in sequence. The outer diameter of the second mating section (113) is larger than the outer diameter of the first mating section (111). At least part of the outer diameter of the transition section (112) gradually decreases in the direction from the second mating section (113) toward the first mating section (111) and forms the first annular stop surface (1121). The valve cover (12) is detachably fastened to the end of the first mating section (111) away from the second mating section (113). One side of the cavity opening of the valve cover (12) abuts against the first annular stop surface (1121) on the transition section (112) to form the annular sealing area (101).

7. The filling valve according to claim 4, characterized in that, The valve cover (12) includes a transition cylinder section (121), an annular abutment section (122), and a limiting section (123) connected coaxially in sequence. The annular abutment section (122) is located at the opening of the transition cylinder section (121), and the limiting section (123) is located at the opening of the transition cylinder section (121). The inner diameter of the annular abutment section (122) is smaller than the inner diameter of the limiting section (123) and larger than the inner diameter of the transition cylinder section (121). The annular abutment section (122) forms a second annular stop step (1201) and has an abutment tip extending circumferentially thereon. The abutment tip abuts against the first annular stop surface (1121) to form the annular sealing area (101). The annular sealing area (101) is an annular sealing line.

8. The filling valve according to claim 1, characterized in that, The filling valve also includes a first annular seal, and the inner wall of the valve cover (12) is sealed to the outer periphery of the valve seat (11) through the first annular seal.

9. The filling valve according to claim 1, characterized in that, The filling valve also includes a second annular seal (14) disposed on the outer periphery of the valve needle assembly (13), and the valve needle assembly (13) is sealed to the inner wall of the cavity of the valve seat (11) through the second annular seal (14).

10. The filling valve according to claim 1, characterized in that, The valve needle assembly (13) includes a valve housing (131) and a valve needle body (132) movably disposed within the valve housing (131). The valve housing (131) is disposed within the valve seat (11) and seals against the inner wall of the valve seat (11). The valve port (1301) is located at the end of the valve housing (131). The end of the valve needle body (132) has a sealing member (133) to block or open the valve port (1301).

11. The filling valve according to claim 10, characterized in that, At least a portion of the outer periphery of the valve housing (131) has external threads, and the inner wall of the valve seat (11) cavity has corresponding internal threads. The valve housing (131) and the valve seat (11) are threadedly connected.

12. An expansion tank, characterized in that, The expansion tank includes a tank body (20), a protective shell (30), and a filling valve as described in any one of claims 1 to 11. The end of the tank body (20) is a convex arc surface and has an air inlet. A first limiting structure (21) is provided at the air inlet. A second limiting structure (1131) is provided at the end of the valve seat (11) of the filling valve away from the valve cover (12). The valve seat (11) of the filling valve is installed at the air inlet and the first limiting structure (21) and the second limiting structure (1131) are mutually limiting and cooperating. The protective shell (30) is fastened to the filling valve and abuts against the end of the tank body (20).

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