Eccentric ball valve

Abstract

The utility model discloses an eccentric ball valve which comprises a valve body, and an inner cavity is formed in the valve body. A valve cover is arranged on the outer wall of the valve body, a channel communicated with the inner cavity is arranged in the valve cover, and the end face, facing the inner cavity, of the channel is a sealing face. A baffle ring is arranged at the end, facing the channel, in the inner cavity, the sealing face is located in the baffle ring, and an annular groove is formed in the baffle ring and communicates with an air supply assembly. Six air blowing holes are evenly distributed in the baffle ring in the circumferential direction at intervals, one end of each air blowing hole communicates with the annular groove, and the other end of each air blowing hole penetrates through the baffle ring in the radial direction of the baffle ring and faces the center of the baffle ring. According to the eccentric ball valve, the sealing face of the channel can be more evenly and effectively purged and cleaned, the purging and cleaning effect is good, and the service life of the eccentric ball valve is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of valves, in particular to an eccentric ball valve. Background Art

[0002] A ball valve generally refers to a valve whose opening and closing part (ball) is driven by the valve stem and rotates around the axis of the ball valve. It can be used for fluid regulation and control. When the ball valve is in the closed state, the ball abuts against the sealing surface of the valve cover channel to achieve the closing function.

[0003] When the ball valve is conveying solid particles or dusty media, there are often some impurities in the media. These impurities accumulate over a long period of time and adhere to the sealing surface of the valve cover channel. After long-term use, it is easy to cause wear of the sealing surface of the channel and the ball, and it is easy to cause an obstruction between the ball and the sealing surface of the channel, causing the ball valve to get stuck. Therefore, it is necessary to purge the sealing surface of the valve cover channel. However, the purge structure on most ball valves currently does not purge the sealing surface of the valve cover channel evenly, and the purge cleaning effect is poor, which can easily cause the ball valve to fail to work normally and reduce the service life of the ball valve. Utility Model Content

[0004] Therefore, the technical problem to be solved by the utility model is to overcome the defects of uneven blowing of the sealing surface of the valve cover channel by the ball valve in the prior art, poor blowing and cleaning effect, resulting in reduced service life of the ball valve, thereby providing an eccentric ball valve.

[0005] An eccentric ball valve provided by the utility model comprises:

[0006] A valve body having an inner cavity therein;

[0007] A valve cover is arranged on the outer wall of the valve body, a channel communicating with the inner cavity is arranged in the valve cover, and an end surface of the channel facing the inner cavity is arranged as a sealing surface;

[0008] A retaining ring is arranged in the inner cavity at one end facing the channel, the sealing surface is located in the retaining ring, an annular groove is provided on the retaining ring, and the annular groove is connected to an air supply component; a plurality of blowing holes are arranged at intervals along the circumferential direction in the retaining ring, one end of the blowing hole is connected to the annular groove, and the other end of the blowing hole passes through the retaining ring along the radial direction of the retaining ring and faces the center of the retaining ring.

[0009] According to an eccentric ball valve of the utility model, at least the following technical effects are achieved:

[0010] An annular groove connected to the air supply assembly is provided on the retaining ring, and a plurality of blowing holes connected to the annular groove are arranged at intervals along the circumference in the retaining ring, the blowing holes penetrate the retaining ring in the radial direction, and the blowing ends face the center of the retaining ring; during the movement of the eccentric ball valve in the opening and closing operation, the air supply assembly blows gas into the annular groove, and through the drainage of the annular groove, the purge gas is blown out from the plurality of blowing holes to the center of the retaining ring at the same time, so that the purge air is blown to the sealing surface of the channel from a plurality of different directions along the circumference at the same time for cleaning, thereby more evenly and effectively blowing and cleaning the sealing surface of the channel, the purge cleaning effect is better, and the service life of the eccentric ball valve is improved. At the same time, because the blowing end of the blowing hole is arranged toward the center of the retaining ring, the blowing end of the blowing hole is close to the sealing surface of the channel, shortening the path of the airflow blown from the blowing end of the blowing hole to the sealing surface, reducing the kinetic energy loss, and improving the purge cleaning effect on the sealing surface of the channel.

[0011] Preferably, a circle of limiting grooves is recessed on the surrounding wall of the inner cavity corresponding to the position of the retaining ring, the retaining ring is embedded in the limiting groove, and the outer peripheral surface of the retaining ring abuts against the inner bottom wall of the limiting groove; the annular groove is recessed on the outer peripheral surface of the retaining ring.

[0012] Preferably, the air supply assembly includes an air supply through hole formed through the side wall of the valve body, one end of the air supply through hole is connected to the annular groove, and the other end of the air supply through hole is connected to an air supply pump.

[0013] Preferably, an air supply pipe is provided on the outer side wall of the valve body, one end of the air supply pipe is connected to the air supply pump, and the other end of the air supply pipe is connected to the air supply through hole.

[0014] Preferably, the air supply pipe and the baffle ring are staggered in the length direction of the channel, and the air supply through hole is inclined gradually approaching the baffle ring inwardly along the radial direction of the baffle ring.

[0015] Preferably, a ball is arranged in the inner cavity, and the ball is driven to rotate by the valve stem; the end surface of the channel facing the inner cavity is arranged as a mounting groove, a valve seat is embedded in the mounting groove, the interior of the valve seat is connected with the channel, the retaining ring abuts against the end surface of the valve seat facing the inner cavity, and the middle part of the end surface of the valve seat facing the inner cavity is convex toward the ball to form the sealing surface; when the eccentric ball valve is in a closed state, the ball abuts against the sealing surface to seal.

[0016] Preferably, a limiting platform is protruding from the surrounding wall of the inner cavity, and the limiting platform is arranged around the circumference of the retaining ring; the part of the inner cavity located between the limiting platform and the valve cover forms the limiting groove.

[0017] Preferably, the sealing surface is configured to be in an arc shape, and one side surface of the sphere is configured to be an arc surface matching the sealing surface; when the eccentric ball valve is in a closed state, the arc surface abuts against and fits the sealing surface.

[0018] Preferably, a filler is provided between the outer side wall of the valve seat and the surrounding wall of the mounting groove.

[0019] Preferably, the retaining ring is arranged concentrically with the channel;

[0020] And / or, the valve cover is concavely provided with a circle of positioning grooves on the end face facing the valve body, and a circle of positioning parts are convexly provided on the valve body at positions corresponding to the positioning grooves, the positioning parts match the positioning grooves, a sealing ring is embedded in the positioning groove, one end face of the sealing ring abuts against the positioning part, and the other end face of the sealing ring abuts against the inner bottom wall of the positioning groove.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a schematic structural diagram of an eccentric ball valve of this embodiment;

[0024] Figure 2 for Figure 1 Schematic diagram of the structure with the sphere removed;

[0025] Figure 3 for Figure 2 The enlarged schematic diagram of point A in the middle;

[0026] Figure 4 This is a schematic cross-sectional view of a retaining ring in an eccentric ball valve of this embodiment;

[0027] Figure 5 The figure is a schematic side view of the structure of a retaining ring in an eccentric ball valve of the present embodiment.

[0028] Description of reference numerals:

[0029] 1-valve body, 11-inner cavity, 111-limiting platform, 12-positioning part;

[0030] 2-valve cover, 21-channel, 211-installation groove, 22-positioning groove;

[0031] 3- retaining ring, 31- annular groove, 32- blowing hole;

[0032] 41-air supply hole, 42-air supply pipe;

[0033] 5- sphere, 51- arc surface;

[0034] 6-valve seat, 61-sealing surface, 62-packing;

[0035] 7- Sealing ring. DETAILED DESCRIPTION

[0036] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0037] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] like Figures 1 to 5The figure shows an eccentric ball valve provided in the present embodiment, comprising a valve body 1, wherein an inner cavity 11 is arranged in the valve body 1; a valve cover 2 is arranged on the outer wall of the valve body 1, wherein a channel 21 connected to the inner cavity 11 is arranged in the valve cover 2, and the end surface of the channel 21 facing the inner cavity 11 is arranged as a sealing surface 61; a retaining ring 3 is arranged at one end of the inner cavity 11 facing the channel 21, and the sealing surface 61 is located in the retaining ring 3, and an annular groove 31 is arranged on the retaining ring 3, and the annular groove 31 is connected to an air supply component; a plurality of blowing holes 32 are evenly distributed along the circumferential interval in the retaining ring 3, preferably six blowing holes 32 are arranged here, one end of the blowing hole 32 is connected to the annular groove 31, and the other end of the blowing hole 32 passes through the retaining ring 3 along the radial direction of the retaining ring 3 and faces the center of the retaining ring 3.

[0041] The eccentric ball valve of the present embodiment is provided with an annular groove 31 connected to the air supply assembly on the retaining ring 3, and six blowing holes 32 connected to the annular groove 31 are evenly distributed along the circumferential direction in the retaining ring 3, and the blowing holes 32 radially penetrate the retaining ring 3, and the blowing ends face the center of the retaining ring 3; when the eccentric ball valve of the present embodiment is in the opening and closing operation, the air supply assembly blows gas into the annular groove 31, and through the drainage of the annular groove 31, the purge gas is blown out from the six blowing holes 32 to the center of the retaining ring 3 at the same time, so that the cleaning air is blown to the sealing surface 61 of the channel 21 from six different directions along the circumferential direction for cleaning, thereby more evenly and effectively blowing and cleaning the sealing surface 61 of the channel 21, and the blowing and cleaning effect is better, thereby improving the service life of the eccentric ball valve of the present embodiment. At the same time, because the blowing end of the blowing hole 32 is set toward the center of the baffle ring 3, the blowing end of the blowing hole 32 is close to the sealing surface 61 of the channel 21, shortening the path of the air flow blown from the blowing end of the blowing hole 32 to the sealing surface 61, reducing kinetic energy loss, and improving the blowing and cleaning effect of the sealing surface 61 of the channel 21.

[0042] It should be noted that the eccentric ball valve of this embodiment uses gas (specifically clean air) as the medium for blowing and cleaning the sealing surface 61 of the channel 21. Compared with using water as the medium for blowing and cleaning, it can effectively prevent water from being retained in the inner cavity 11, thereby avoiding adverse effects such as dilution on the liquid fluid flowing through the inner cavity 11.

[0043] In specific applications, the number of the blowing holes 32 is reasonably increased or decreased according to the inner diameter of the retaining ring 3 and the size of the sealing surface 61 of the channel 21. For example, in other embodiments, the blowing holes 32 are provided with two, three, four, five, seven, eight, ten or other numbers.

[0044] Specifically, the retaining ring 3 is arranged concentrically with the channel 21, so that the paths of the purge air flows blown out from six different circumferential directions to the corresponding positions of the sealing surface 61 are basically the same, thereby more evenly and effectively purging and cleaning the sealing surface 61 of the channel 21.

[0045] Specifically, the valve cover 2 is connected to the valve body 1 by screws.

[0046] Optionally, a circle of limiting grooves is recessed on the surrounding wall of the inner cavity 11 corresponding to the position of the retaining ring 3, the retaining ring 3 is embedded in the limiting groove, and the outer peripheral surface of the retaining ring 3 abuts against the inner bottom wall of the limiting groove; the annular groove 31 is recessed on the outer peripheral surface of the retaining ring 3. First, the installation position of the retaining ring 3 is accurately positioned through the limiting groove to ensure that the airflow blown out from the blowing end of the blowing hole 32 is fully applied to the sealing surface 61 of the channel 21, ensuring the purging and cleaning effect of the sealing surface 61 of the channel 21. Secondly, by recessing the annular groove 31 on the outer circumferential surface of the retaining ring 3, and the outer circumferential surface of the retaining ring 3 abutting against the inner bottom wall of the limiting groove, on the one hand, it is convenient to process the annular groove 31 on the retaining ring 3, thereby reducing the production cost; on the other hand, the sealing performance of the space enclosed by the annular groove 31 and the inner bottom wall of the limiting groove is better, so as to guide the gas blown in through the air supply component and reduce the loss of airflow energy, so that the purge gas can be blown out from the six blowing holes 32 to the sealing surface 61 of the channel 21 at a relatively high speed for cleaning, thereby ensuring the purge cleaning effect of the sealing surface 61 of the channel 21.

[0047] like Figure 1 and Figure 2 As shown, optionally, the air supply assembly includes an air supply through hole 41 formed through the side wall of the valve body 1, one end of the air supply through hole 41 is connected to the annular groove 31, and the other end of the air supply through hole 41 is connected to an air supply pump. During the movement of the eccentric ball valve of this embodiment in the opening and closing operation, the air supply pump is started to blow the gas into the annular groove 31 through the air supply through hole 41, and the gas is guided by the annular groove 31, so that the purge gas is blown out from the six blowing holes 32 to the center of the retaining ring 3 at the same time, so that the purge air is blown out to the sealing surface 61 of the channel 21 from six different directions along the circumferential direction at the same time for cleaning, thereby more evenly and effectively purging and cleaning the sealing surface 61 of the channel 21. As another alternative scheme of the present technical solution, the air supply assembly includes an air supply through hole 41, one end of the air supply through hole 41 penetrates the side wall of the valve cover 2 and is connected to the air supply pump; the other end of the air supply through hole 41 penetrates the side wall of the valve body 1 and is connected to the annular groove 31.

[0048] In specific applications, the air supply pump may also be replaced by a conventional purge device that can realize the function of delivering the flowing purge airflow into the annular groove 31 .

[0049] like Figures 1 to 3 As shown, optionally, an air supply pipe 42 is provided on the outer wall of the valve body 1, one end of the air supply pipe 42 is connected to the air supply pump, and the other end is connected to the air supply through hole 41. Through the transition of the air supply pipe 42, the air supply pump is better connected to the air supply through hole 41, so as to transport the flowing purge air flow into the air supply through hole 41. Figure 2 As shown, specifically, the inner diameter of the air supply pipe 42 is larger than the aperture of the air supply hole 41. Because the aperture of the connection between the air outlet end of the air supply pipe 42 and the air inlet end of the air supply hole 41 becomes smaller, the flow rate of the purge airflow is accelerated when it passes through the air supply pipe 42 and enters the air supply hole 41, thereby increasing the kinetic energy contained in the purge airflow and improving the purge cleaning effect on the sealing surface 61 of the channel 21.

[0050] like Figure 1 and Figure 3 As shown, optionally, the air supply pipe 42 and the baffle ring 3 are staggered along the length direction of the channel 21, and the air supply through hole 41 is inclined inwardly and gradually approaches the baffle ring 3 along the radial direction of the baffle ring 3. Compared with the radial arrangement of the air supply through hole 41 parallel to the baffle ring 3, the inclined air supply through hole 41 in this embodiment can reduce the collision impact force generated by the surrounding wall of the annular groove 31 when the purge airflow flows into the annular groove 31, thereby reducing the kinetic energy loss of the purge airflow, so that the purge airflow is blown toward the sealing surface 61 of the channel 21 at a higher speed for purge cleaning, thereby ensuring the purge cleaning effect of the sealing surface 61 of the channel 21. It can be understood that the length direction of the channel 21 described in this embodiment refers to Figure 1 The first direction in .

[0051] like Figures 1 to 3As shown, optionally, a ball 5 is arranged in the inner cavity 11, and the ball 5 is driven to rotate by the valve stem; the end surface of the channel 21 facing the inner cavity 11 is arranged as a mounting groove 211, and a valve seat 6 is embedded in the mounting groove 211, and the interior of the valve seat 6 is communicated with the channel 21, and the retaining ring 3 abuts against the end surface of the valve seat 6 facing the inner cavity 11, and the middle of the end surface of the valve seat 6 facing the inner cavity 11 is convexly provided toward the ball 5 to form the sealing surface 61; when the eccentric ball valve is in a closed state, the ball 5 abuts against the sealing surface 61 for blocking. The ball 5 is driven to rotate by the valve stem extending from one end to the outside of the valve body 1, so as to conveniently control the opening and closing operation of the eccentric ball valve of this embodiment, and at the same time, a valve seat 6 made of hard material is added as a component abutting and fitting with the ball 5 to achieve blocking, which can effectively avoid the phenomenon that the sealing surface 61 is worn and leaks after a short period of use. Because the abutment between the ball 5 and the sealing surface 61 is located inside the retaining ring 3, when the eccentric ball valve of this embodiment is in the opening and closing operation, the blowing hole 32 can not only evenly and effectively blow and clean the sealing surface 61 of the channel 21, but also evenly and effectively blow and clean the side wall where the ball 5 and the sealing surface 61 abut.

[0052] like Figure 2 and Figure 3 As shown, specifically, a packing 62 is provided between the outer side wall of the valve seat 6 and the surrounding wall of the mounting groove 211. The packing 62 can ensure the sealing performance between the valve seat 6 and the mounting groove 211.

[0053] like Figure 2 and Figure 3 As shown, optionally, a limiting platform 111 is convexly provided on the surrounding wall of the inner cavity 11, and the limiting platform 111 is arranged around the circumference of the retaining ring 3; the portion of the inner cavity 11 between the limiting platform 111 and the valve cover 2 forms the limiting groove. By embedding the retaining ring 3 in the end face of the inner cavity 11 facing the valve cover 2, in the process of assembling the eccentric ball valve of this embodiment, it is only necessary to embed the retaining ring 3 in the end face of the inner cavity 11 facing the valve cover 2, and then connect the valve cover 2 with the valve body 1. At this time, the retaining ring 3 can be accurately installed in the inner cavity 11, and the valve seat 6 can be accurately installed in the installation groove 211, and the overall assembly difficulty is low and the assembly process is simple.

[0054] like Figure 1 As shown, optionally, the sealing surface 61 is set to an arc shape, and one side surface of the sphere 5 is set to an arc surface 51 matching the sealing surface 61; when the eccentric ball valve is in a closed state, the arc surface 51 abuts against the sealing surface 61, the abutting area is larger, the sealing effect is better, and leakage is more effectively avoided.

[0055] like Figure 1 and Figure 3As shown, optionally, a circle of positioning parts 12 is convexly provided on the valve body 1 at the position corresponding to the positioning groove 22, and the positioning part 12 matches the positioning groove 22. A sealing ring 7 is embedded in the positioning groove 22, and one end face of the sealing ring 7 abuts against the positioning part 12, and the other end face of the sealing ring 7 abuts against the inner bottom wall of the positioning groove 22. The positioning groove 22 provides a space for the sealing ring 7 to be installed and limited, so as to avoid the sealing ring 7 from falling off during the process of aligning the valve cover 2 with the valve body 1 for assembly, thereby reducing the difficulty of assembly; at the same time, after the assembly is completed, the two ends of the sealing ring 7 abut against the inner bottom wall of the positioning groove 22 and the end face of the positioning part 12 facing the valve cover 2, respectively, so as to further improve the sealing performance of the abutting and fitting part of the valve body 1 and the valve cover 2.

[0056] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention of the utility model.

Claims

1. An eccentric ball valve, characterized in that: include: A valve body (1) is provided with an inner cavity (11); A valve cover (2) is arranged on the outer wall of the valve body (1), wherein a channel (21) communicating with the inner cavity (11) is arranged in the valve cover (2), and an end surface of the channel (21) facing the inner cavity (11) is arranged as a sealing surface (61); A retaining ring (3) is arranged in the inner cavity (11) at one end facing the channel (21), the sealing surface (61) is located in the retaining ring (3), an annular groove (31) is provided on the retaining ring (3), and the annular groove (31) is connected to an air supply component; a plurality of blowing holes (32) are arranged at intervals along the circumferential direction in the retaining ring (3), one end of the blowing hole (32) is connected to the annular groove (31), and the other end of the blowing hole (32) penetrates the retaining ring (3) along the radial direction of the retaining ring (3) and faces the center of the retaining ring (3).

2. An eccentric ball valve according to claim 1, characterized in that: A circle of limiting grooves is recessed on the surrounding wall of the inner cavity (11) corresponding to the position of the retaining ring (3), and the retaining ring (3) is embedded in the limiting groove, and the outer peripheral surface of the retaining ring (3) abuts against the inner bottom wall of the limiting groove; the annular groove (31) is recessed on the outer peripheral surface of the retaining ring (3).

3. An eccentric ball valve according to claim 2, characterized in that: The air supply assembly comprises an air supply through hole (41) formed through the side wall of the valve body (1), one end of the air supply through hole (41) is connected to the annular groove (31), and the other end of the air supply through hole (41) is connected to an air supply pump.

4. An eccentric ball valve according to claim 3, characterized in that: An air supply pipe (42) is provided on the outer wall of the valve body (1), one end of the air supply pipe (42) is connected to the air supply pump, and the other end is connected to the air supply through hole (41).

5. An eccentric ball valve according to claim 4, characterized in that: The air supply pipe (42) and the baffle ring (3) are arranged staggered along the length direction of the channel (21), and the air supply through hole (41) is arranged inclined gradually inwardly and close to the baffle ring (3) along the radial direction of the baffle ring (3).

6. An eccentric ball valve according to claim 2, characterized in that: A ball (5) is arranged in the inner cavity (11), and the ball (5) is driven to rotate by the valve stem; the end surface of the channel (21) facing the inner cavity (11) is arranged as a mounting groove (211), and a valve seat (6) is embedded in the mounting groove (211); the interior of the valve seat (6) is communicated with the channel (21); the retaining ring (3) abuts against the end surface of the valve seat (6) facing the inner cavity (11); the middle part of the end surface of the valve seat (6) facing the inner cavity (11) is convexly arranged toward the ball (5) to form the sealing surface (61); when the eccentric ball valve is in a closed state, the ball (5) abuts against the sealing surface (61) to seal.

7. An eccentric ball valve according to claim 6, characterized in that: A limiting platform (111) is protrudingly provided on the surrounding wall of the inner cavity (11), and the limiting platform (111) is arranged around the circumference of the retaining ring (3); the portion of the inner cavity (11) located between the limiting platform (111) and the valve cover (2) forms the limiting groove.

8. An eccentric ball valve according to claim 6, characterized in that: The sealing surface (61) is configured to be in an arc shape, and one side surface of the spherical body (5) is configured to be an arc surface (51) matching the sealing surface (61); when the eccentric ball valve is in a closed state, the arc surface (51) abuts against and fits the sealing surface (61).

9. The eccentric ball valve according to claim 6, characterized in that: A packing (62) is provided between the outer wall of the valve seat (6) and the surrounding wall of the installation groove (211).

10. The eccentric ball valve according to claim 1, characterized in that: The retaining ring (3) is arranged concentrically with the channel (21); And / or, the valve cover (2) is provided with a circle of positioning grooves (22) on the end surface facing the valve body (1), and a circle of positioning portions (12) is provided on the valve body (1) at positions corresponding to the positioning grooves (22), the positioning portions (12) match the positioning grooves (22), a sealing ring (7) is embedded in the positioning groove (22), one end surface of the sealing ring (7) abuts against the positioning portion (12), and the other end surface of the sealing ring (7) abuts against the inner bottom wall of the positioning groove (22).

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