CN221838938U - A top-mounted floating ball valve structure with easily replaceable valve seat - Google Patents

Abstract

The utility model discloses an upper-mounted floating ball valve structure with an easily-replaced valve seat, belongs to the technical field of valves, and aims to solve the problem that the valve seat cannot be maintained and replaced on line by a floating ball valve. The valve body is provided with a valve cavity, a medium inlet and a medium outlet of the valve body are communicated through the valve cavity, an upper mounting port for the upper mounting sealing assembly to go in and out is formed in the upper side of the valve cavity, and the valve cover is sealed or opened; the upper sealing assembly comprises two baffle rings, two soft valve seats and a valve ball, wherein the end faces of one side, opposite to the baffle rings, of each baffle ring are provided with chambers, the two soft valve seats are embedded into the two chambers in a one-to-one correspondence manner, and the two soft valve seats are respectively coaxially arranged on two sides of the valve ball. The whole set of upper sealing assembly can be installed in or taken out of the valve body through the upper installing port, and the valve seat and the ball body are convenient to be inspected and maintained on line without disassembling the valve seat from a pipeline when inspection and maintenance are needed.

Description

A top-mounted floating ball valve structure with easily replaceable valve seat

Technical Field

The utility model belongs to the technical field of valves, and in particular relates to a top-mounted floating ball valve structure with an easily replaceable valve seat.

Background Art

Floating ball valves are widely used in key locations of process pipelines such as oil pipelines and nuclear power systems. They seal with forced force and play a role in safety cutoff. Most applications of floating ball valves require online repair and replacement of valve seats. Currently, floating ball valves on the market are generally two-piece or three-piece valve bodies. Generally, the valve body is disassembled to repair and replace the valve seat. Disassembly of the valve body requires the floating ball valve to be removed from the pipeline first, which is time-consuming and labor-intensive, and online repair and replacement of the valve seat cannot be achieved.

Utility Model Content

The purpose of the utility model is to provide a top-mounted floating ball valve structure with an easy-to-replace valve seat, so as to solve the problem that the floating ball valve cannot realize online maintenance and replacement of the valve seat. The technical solution adopted by the utility model is as follows:

A top-mounted floating ball valve structure with an easily replaceable valve seat comprises a valve body, a valve cover, a valve shaft and a top-mounted sealing assembly, wherein the valve body is provided with a valve cavity, a medium inlet and a medium outlet of the valve body are connected through the valve cavity, an upper mounting port for the top-mounted sealing assembly to enter and exit is provided on the upper side of the valve cavity, and the valve cover seals or opens the upper mounting port;

The upper sealing assembly comprises two retaining rings, two soft valve seats and a valve ball. The end surfaces on the opposite sides of the two retaining rings are provided with chambers. The two soft valve seats are embedded in the two chambers one by one. The two soft valve seats are coaxially arranged on both sides of the valve ball. The edge of the end surface of the retaining ring on the side away from the valve ball is provided with a chamfered structure. The end surface of the retaining ring on the side away from the valve ball is provided with a first sealing ring. The circumference and bottom surface of the upper sealing assembly are respectively adapted to the circumference and bottom surface of the valve cavity. When the upper sealing assembly is installed in the valve body, the inner holes of the two retaining rings are respectively corresponding to the medium inlet and the medium outlet through the first sealing ring for sealing communication, and the valve covers are respectively against the upper ends of the two retaining rings;

The lower end of the valve shaft passes through the valve cover and is plugged into the valve ball. The center of the valve ball is aligned with the axial center line of the valve shaft. The valve shaft and the valve cover rotate and seal. A connecting sleeve is provided at the upper end of the valve shaft. One end of the handle is connected to the connecting sleeve. When the valve is fully opened, the inner holes of the two soft valve seats are connected through the inner hole of the valve ball. When the valve is fully closed, the valve ball seals the two soft valve seats respectively.

Furthermore, the soft valve seat includes a root structure and a flexible lip structure. The root structure is cylindrical, and the outer periphery of the flexible lip structure is connected to the inner periphery of the root structure. The cross-section of the flexible lip structure is a trapezoid with the upper bottom located at the inner periphery and the lower bottom located at the outer periphery. The outer periphery of the root structure is interference fit with the side wall of the corresponding chamber, and one end face of the root structure abuts against the bottom surface of the corresponding chamber. The inner diameter end of the flexible lip structure is a lip edge that cooperates with the valve ball seal, and a storage elastic deformation zone is formed between the flexible lip structure and the bottom surface of the corresponding chamber. When the flexible lip structure cooperates with the valve ball seal, the lip edge bends toward the corresponding storage elastic deformation zone.

Furthermore, an annular groove is formed between the trapezoidal waist of the flexible lip structure on the side close to the valve ball and the inner circumference of the root structure, and a plurality of root grooves are arranged on the circumference of one end of the inner circumference of the root structure close to the valve ball. When the valve ball cooperates with the flexible lip structure, the medium enters the annular groove through the plurality of root grooves, and a plurality of axially penetrating outer diameter grooves are arranged on the outer circumference of the root structure.

Furthermore, the valve cover is provided with a cover inner hole, the valve shaft passes through the valve cover through the cover inner hole, two second sealing rings are provided on the hole wall of the cover inner hole, and the valve shaft is rotatably sealed with the valve cover through the two second sealing rings.

Furthermore, a stuffing box is provided on the valve cover, and the stuffing box is connected with the inner hole of the cover up and down. A sealing packing is provided in the stuffing box. The valve shaft is rotatably sealed with the valve cover through the sealing packing. A disc spring group and a compression sleeve are sleeved on the valve shaft. The compression ring is threadedly matched with the valve shaft. The compression ring presses the sealing packing on the bottom surface of the stuffing box through the disc spring group and the compression sleeve in turn. A shaft shoulder is provided on the lower part of the valve shaft, and the shaft shoulder and the sealing packing are clamped on both sides of the valve cover.

Furthermore, a booster pad is sleeved on the valve shaft, and the booster pad is a polytetrafluoro gasket, and the shaft shoulder is rotatably matched with the valve cover through the booster pad.

Furthermore, a first blind hole is provided on the outer periphery of the valve shaft, a first anti-static spring and an anti-static steel ball are provided in the first blind hole, the valve shaft is connected to the hole wall of the inner hole of the cover through the first anti-static spring and the anti-static steel ball in turn, a second blind hole is provided on the lower end surface of the valve shaft, a second anti-static spring is provided in the second blind hole, and both ends of the second anti-static spring are respectively connected to the valve shaft and the valve ball.

Furthermore, the valve cover and the valve body are sealed and connected via a third sealing ring and a sealing gasket.

Furthermore, two process screw holes are provided on the upper end surface of the retaining ring.

Furthermore, the valve cover is provided with a limit pin coaxially arranged with the valve shaft, and two limit protrusions are provided on the outer periphery of the connecting sleeve. The included angle between the two limit protrusions is 90°, and the limit pin is located between the two limit protrusions. When the valve is fully opened, one limit protrusion abuts against the outer periphery of the limit pin, and when the valve is fully closed, the other limit protrusion abuts against the outer periphery of the limit pin.

Compared with the prior art, the beneficial effects of the utility model are:

1. The utility model has an upper loading port on the upper side of the valve cavity for the upper loading sealing assembly to enter and exit. The entire upper loading sealing assembly can be loaded into or taken out of the valve body through the upper loading port. When inspection and maintenance are required, there is no need to disassemble the utility model from the pipeline, which is convenient for online inspection and maintenance of the ball and valve seat. The retaining ring is provided with a chamfered structure, and the triangular cavity formed between the chamfered structure and the valve body is sealed by the first sealing ring, which can prevent the retaining ring and the valve body from being tightly matched and causing seizure, and facilitate the disassembly and assembly of the upper loading sealing assembly.

2. The soft valve seat is equivalent to an annular beam with a fixed outer end and an axially bendable inner end. When the lip edge bends toward the corresponding storage elastic deformation zone, the flexible lip structure has a restoring elastic force, which is applied to the valve ball to ensure reliable sealing. In addition to the sealing function, the soft valve seat can also play the role of a bearing. The two soft valve seats support the ball so that the valve ball is kept on the axis of the valve shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of the structure of the utility model;

FIG2 is a schematic diagram of the structure of the valve body;

FIG3 is a schematic diagram of the structure of a retaining ring;

Fig. 4 is a cross-sectional view taken along line B-B of Fig. 2;

FIG5 is a schematic diagram of a cross-sectional bending of a soft valve seat;

Fig. 6 is an axonometric view of the soft valve seat;

FIG. 7 is an enlarged view of point A in FIG. 1 .

In the figure, 1. valve body, 11. valve cavity, 12. medium inlet, 13. medium outlet, 14. upper loading port, 2. retaining ring, 21. first sealing ring, 22. chamber, 23. process screw hole, 3. soft valve seat, 31. root groove, 32. outer diameter groove, 33. metal elastic ring, 34. root structure, 35. flexible lip structure, 4. valve ball, 5. valve cover, 51. third sealing ring, 52. sealing pad, 53. limit pin, 6. connecting sleeve, 61. handle, 7. valve shaft, 71. pressure ring, 72. disc spring assembly, 73. sealing packing, 74. second sealing ring, 75. pressure sleeve, 76. first anti-static spring, 77. anti-static steel ball, 78. booster pad, 79. second anti-static spring, 710. shaft shoulder.

Implementation

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is described below by specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the utility model. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the utility model.

The connection mentioned in the present utility model is divided into fixed connection and detachable connection. The fixed connection is a non-detachable connection, including but not limited to conventional fixed connection methods such as folding connection, rivet connection, bonding connection and welding connection. The detachable connection includes but is not limited to conventional detachable methods such as bolt connection, snap connection, pin connection and hinge connection. When the specific connection method is not clearly defined, it is assumed that at least one connection method can be found in the existing connection methods to achieve the function, and those skilled in the art can choose according to their needs. For example: choose welding connection for fixed connection and bolt connection for detachable connection.

The present invention will be further described in detail below in conjunction with the accompanying drawings. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

Embodiment: As shown in Fig. 1-7, a top-mounted floating ball valve structure with an easily replaceable valve seat comprises a valve body 1, a valve cover 5, a valve shaft 7 and a top-mounted sealing assembly. The valve body 1 is provided with a valve cavity 11, a medium inlet 12 and a medium outlet 13 of the valve body 1 are connected through the valve cavity 11, a top-mounted port 14 for the top-mounted sealing assembly to enter and exit is opened on the upper side of the valve cavity 11, and the valve cover 5 seals or opens the top-mounted port 14;

The upper sealing assembly comprises two retaining rings 2, two soft valve seats 3 and a valve ball 4. The end surfaces of the two retaining rings 2 on opposite sides are provided with chambers 22. The two soft valve seats 3 are embedded in the two chambers 22 in a one-to-one correspondence. The two soft valve seats 3 are coaxially arranged on both sides of the valve ball 4, respectively. The edge of the end surface of the retaining ring 2 on the side away from the valve ball 4 is provided with a chamfered structure, and the end surface of the retaining ring 2 on the side away from the valve ball 4 is provided with a first sealing ring 21. The circumference and bottom surface of the upper sealing assembly are respectively adapted to the circumference and bottom surface of the valve cavity 11. When the upper sealing assembly is installed in the valve body 1, the inner holes of the two retaining rings 2 are respectively corresponding to the medium inlet 12 and the medium outlet 13 through the first sealing ring 21 for sealing communication, and the valve cover 5 is respectively against the upper ends of the two retaining rings 2;

The lower end of the valve shaft 7 passes through the valve cover 5 and is plugged into the valve ball 4. The center of the valve ball 4 is aligned with the axial center line of the valve shaft 7. The valve shaft 7 and the valve cover 5 rotate and seal. The upper end of the valve shaft 7 is provided with a connecting sleeve 6. One end of the handle 61 is connected to the connecting sleeve 6. When the valve is fully opened, the inner holes of the two soft valve seats 3 are connected through the inner holes of the valve ball 4. When the valve is fully closed, the valve ball 4 seals the two soft valve seats 3 respectively.

The utility model has an upper loading port 14 on the upper side of the valve cavity 11 for the upper loading sealing assembly to enter and exit. The entire upper loading sealing assembly can be loaded into or taken out of the valve body 11 through the upper loading port 14. When inspection and maintenance are required, there is no need to disassemble the utility model from the pipeline, which is convenient for online inspection and maintenance of the ball and valve seat. The retaining ring 2 is provided with a chamfered structure, and the triangular cavity formed between the chamfered structure and the valve body 1 is sealed by the first sealing ring 21, which can prevent the retaining ring 2 and the valve body 1 from being tightly matched and causing biting, and facilitate the disassembly and assembly of the upper loading sealing assembly.

The soft valve seat 3 includes a root structure 34 and a flexible lip structure 33. The root structure 34 is cylindrical. The outer periphery of the flexible lip structure 33 is connected to the inner periphery of the root structure 34. The cross-section of the flexible lip structure 33 is a trapezoid with the upper bottom located at the inner periphery and the lower bottom located at the outer periphery. The outer periphery of the root structure 34 is interference fit with the side wall of the corresponding chamber 22. One end face of the root structure 34 abuts against the bottom surface of the corresponding chamber 22. The inner diameter end of the flexible lip structure 33 is a lip edge that seals with the valve ball 4. A storage elastic deformation zone is formed between the flexible lip structure 33 and the bottom surface of the corresponding chamber 22. When the flexible lip structure 33 seals with the valve ball 4, the lip edge bends toward the corresponding storage elastic deformation zone. Figure 5 shows a schematic diagram of the cooperation between the soft valve seat 3 and the retaining ring 2. The solid line mark 33 represents the state of the flexible lip structure 33 after deformation, and the dotted line mark 33 represents the state of the flexible lip structure 33 before deformation. The soft valve seat 3 is equivalent to an annular beam with a fixed outer end and an axially bendable inner end. When the lip edge bends toward the corresponding storage elastic deformation zone, the flexible lip structure 33 has a restoring elastic force, which is applied to the valve ball 4 to ensure reliable sealing. In addition to the sealing function, the soft valve seat 3 can also play the role of a bearing. The two soft valve seats 3 support the sphere so that the valve ball 4 is kept on the axial center line of the valve shaft 7.

An annular groove is formed between the trapezoidal waist of the flexible lip structure 33 on one side close to the valve ball 4 and the inner circumference of the root structure 34. A plurality of root grooves 31 are arranged on the inner circumference of the root structure 34 close to one end of the valve ball 4. When the valve ball 4 cooperates with the flexible lip structure 33, the medium enters the annular groove through the plurality of root grooves 31. A plurality of axially penetrating outer diameter grooves 32 are arranged on the outer circumference of the root structure 34. The outer diameter grooves 32 can disperse the upstream pressure to both sides of the soft valve seat 3, and the root grooves 31 can allow the medium to enter the annular groove, thereby eliminating the rotational force generated by the pressure imbalance and reducing the torque of the switch valve operation.

The valve cover 5 is provided with a cover inner hole, and the valve shaft 7 passes through the valve cover 5 through the cover inner hole. Two second sealing rings 74 are provided on the hole wall of the cover inner hole. The valve shaft 7 rotates and seals with the valve cover 5 through the two second sealing rings 74.

The valve cover 5 is provided with a stuffing box, which is connected with the inner hole of the cover up and down, and a sealing packing 73 is provided in the stuffing box. The valve shaft 7 is rotatably sealed with the valve cover 5 through the sealing packing 73. The valve shaft 7 is sleeved with a disc spring group 72 and a pressing sleeve 75, and the pressing ring 71 is threadedly matched with the valve shaft 7. The pressing ring 71 presses the sealing packing 73 on the bottom surface of the stuffing box through the disc spring group 72 and the pressing sleeve 75 in turn. The lower part of the valve shaft 7 is provided with a shaft shoulder 710, and the shaft shoulder 710 and the sealing packing 73 are clamped on both sides of the valve cover 5. The valve shaft 7 and the valve cover 5 are connected in the form of a double-pass second sealing ring 74 and a sealing packing 73, and are equipped with a disc spring group 72 to compress the sealing packing 73, so that the valve shaft 7 and the valve cover 5 are reliably sealed.

The valve shaft 7 is sleeved with a booster pad 78, which is a PTFE gasket, and the shaft shoulder 710 is rotatably matched with the valve cover 5 through the booster pad 78. The booster pad 78 acts as a sliding bearing, which can reduce the torque required when the valve shaft 7 rotates.

The outer periphery of the valve shaft 7 is provided with a first blind hole, in which a first antistatic spring 76 and an antistatic steel ball 77 are provided, and the valve shaft 7 is connected to the hole wall of the inner hole of the cover through the first antistatic spring 76 and the antistatic steel ball 77 in sequence, and a second blind hole is provided on the lower end surface of the valve shaft 7, in which a second antistatic spring 79 is provided, and the two ends of the second antistatic spring 79 are respectively connected to the valve shaft 7 and the valve ball 4. The valve ball 4 and the valve cover 5 are respectively connected to the valve shaft 7 by electrostatic conduction, and the valve body 1 is connected to the electrostatic grounding device, which can eliminate accidents caused by static electricity.

The valve cover 5 and the valve body 1 are sealed and connected via a third sealing ring 51 and a sealing gasket 52, so that the seal is reliable and stable.

Two process screw holes 23 are arranged on the upper end surface of the retaining ring 2. When the upper mounted sealing assembly is disassembled, the upper mounted sealing assembly can be taken out of the valve body 1 as a whole by connecting the hanging screws with the process screw holes 23.

The valve cover 5 is provided with a limit pin 53 which is arranged coaxially with the valve shaft 7, and the outer periphery of the connecting sleeve 6 is provided with two limit protrusions, the included angle between the two limit protrusions is 90°, and the limit pin 53 is located between the two limit protrusions. When the valve is fully opened, one of the limit protrusions abuts against the outer periphery of the limit pin 53, and when the valve is fully closed, the other limit protrusion abuts against the outer periphery of the limit pin 53.

The above embodiments are merely illustrative of the present invention and do not limit its protection scope. Those skilled in the art may also make partial changes thereto, which are within the protection scope of the present invention as long as they do not exceed the spirit of the present invention.

Claims (10)

1. An upper-mounted floating ball valve structure with a valve seat easy to replace, which is characterized in that: the valve comprises a valve body (1), a valve cover (5), a valve shaft (7) and a top-loading sealing assembly, wherein the valve body (1) is provided with a valve cavity (11), a medium inlet (12) and a medium outlet (13) of the valve body (1) are communicated through the valve cavity (11), a top-loading opening (14) for the top-loading sealing assembly to go in and out is formed in the upper side of the valve cavity (11), and the valve cover (5) seals or opens the top-loading opening (14);

The upper mounting sealing assembly comprises two baffle rings (2), two soft valve seats (3) and a valve ball (4), wherein the opposite side end surfaces of the two baffle rings (2) are respectively provided with a cavity (22), the two soft valve seats (3) are embedded into the two cavities (22) in a one-to-one correspondence manner, the two soft valve seats (3) are respectively coaxially arranged at two sides of the valve ball (4), the edge of one side end surface of the baffle ring (2) deviating from the valve ball (4) is provided with a chamfer structure, the side end surface of the baffle ring (2) deviating from the valve ball (4) is provided with a first sealing ring (21), the circumferential direction and the bottom surface of the upper mounting sealing assembly are respectively matched with the circumferential direction and the bottom surface of the valve cavity (11), when the upper mounting sealing assembly is mounted in the valve body (1), the inner holes of the two baffle rings (2) are respectively correspondingly communicated with the medium inlet (12) and the medium outlet (13) in a sealing manner through the first sealing ring (21), and the valve cover (5) is respectively abutted against the upper ends of the two baffle rings (2);

The lower extreme of valve shaft (7) passes valve gap (5) to peg graft the cooperation with valve ball (4), the centre of sphere of valve ball (4) aligns with the axial lead of valve shaft (7), valve shaft (7) and valve gap (5) rotate sealed cooperation, the upper end of valve shaft (7) is equipped with adapter sleeve (6), the one end and the adapter sleeve (6) of handle (61) link to each other, when opening the valve completely, the hole of two soft disk seats (3) communicates through the hole of valve ball (4), when closing the valve completely, valve ball (4) seal two soft disk seats (3) respectively.

2. The easy-to-replace valve seat upper-mounted floating ball valve structure according to claim 1, wherein: the soft valve seat (3) comprises a root structure (34) and a flexible lip structure (33), the root structure (34) is in a cylindrical shape, the periphery of the flexible lip structure (33) is connected with the inner periphery of the root structure (34), the section of the flexible lip structure (33) is a trapezoid with the upper bottom located on the inner periphery and the lower bottom located on the periphery, the periphery of the root structure (34) is in interference fit with the side wall of the corresponding chamber (22), one end face of the root structure (34) abuts against the bottom surface of the corresponding chamber (22), the inner diameter end of the flexible lip structure (33) is a lip in sealing fit with the valve ball (4), a storage elastic deformation area is formed between the flexible lip structure (33) and the bottom surface of the corresponding chamber (22), and when the flexible lip structure (33) is in sealing fit with the valve ball (4), the lip is bent towards the corresponding storage elastic deformation area.

3. The easy-to-replace valve seat upper-mounted floating ball valve structure according to claim 2, wherein: an annular groove is formed between a trapezoid waist on one side of the flexible lip structure (33) close to the valve ball (4) and the inner circumference of the root structure (34), a plurality of root grooves (31) are formed in the inner circumference of the root structure (34) close to one end circumference of the valve ball (4), when the valve ball (4) is matched with the flexible lip structure (33), a medium enters the annular groove through the root grooves (31), and a plurality of axially-through outer diameter grooves (32) are formed in the outer circumference of the root structure (34).

4. The easy-to-replace valve seat upper-mounted floating ball valve structure according to claim 1, wherein: be equipped with lid hole on valve gap (5), valve shaft (7) by lid hole passes valve gap (5), be equipped with two second sealing washer (74) on the pore wall of lid hole, valve shaft (7) are through two second sealing washer (74) and valve gap (5) rotation sealing fit.

5. The easy-to-replace valve seat upper-mounted floating ball valve structure according to claim 4, wherein: be equipped with the packing box on valve gap (5), the packing box with the lid hole communicates from top to bottom, be equipped with sealing filler (73) in the packing box, valve shaft (7) pass through sealing filler (73) and valve gap (5) rotation sealing fit, cup joint dish spring group (72) and press cover (75) on valve shaft (7), press ring (71) and valve shaft (7) screw-thread fit, press ring (71) loop through dish spring group (72) and press cover (75) are in sealing filler (73) are pressed on the bottom surface of packing box, the lower part of valve shaft (7) is equipped with shoulder (710), shoulder (710) and sealing filler (73) clamp in the both sides of valve gap (5).

6. The easy-to-replace valve seat upper-mounted floating ball valve structure according to claim 5, wherein: the valve shaft (7) is sleeved with a power-assisted pad (78), the power-assisted pad (78) is a tetrafluoro gasket, and the shaft shoulder (710) is in rotary fit with the valve cover (5) through the power-assisted pad (78).

7. The easy-to-replace valve seat upper-mounted floating ball valve structure according to claim 4, wherein: the periphery of valve shaft (7) is equipped with first blind hole, be equipped with first antistatic spring (76) and antistatic steel ball (77) in the first blind hole, valve shaft (7) loop through first antistatic spring (76) and antistatic steel ball (77) with the pore wall of lid hole supports and leans on and links to each other, is equipped with the second blind hole on the lower terminal surface of valve shaft (7), be equipped with second antistatic spring (79) in the second blind hole, the both ends of second antistatic spring (79) link to each other with valve shaft (7) and valve ball (4) respectively.

8. The easy-to-replace valve seat upper-mounted floating ball valve structure according to claim 1, wherein: the valve cover (5) is in sealing connection with the valve body (1) through a third sealing ring (51) and a sealing gasket (52).

9. The easy-to-replace valve seat upper-mounted floating ball valve structure according to claim 1, wherein: the upper end face of the baffle ring (2) is provided with two process screw holes (23).

10. The easy-to-replace valve seat upper-loading floating ball valve structure according to any one of claims 1-9, wherein: be equipped with on valve gap (5) with valve shaft (7) coaxial spacing nail (53) that set up, the periphery of adapter sleeve (6) is equipped with two spacing archs, two spacing bellied contained angle is 90, spacing nail (53) are located two spacing between the arch, when opening the valve completely, one spacing arch supports with the periphery of spacing nail (53) and leans on the cooperation, when closing the valve completely, another spacing arch supports with the periphery of spacing nail (53) and leans on the cooperation.