CN114658861B

CN114658861B - Diaphragm valve

Info

Publication number: CN114658861B
Application number: CN202210354789.5A
Authority: CN
Inventors: 黄文博; 陆文军; 聂敏
Original assignee: Kunshan Kinglai Hygienic Materials Co Ltd
Current assignee: Kunshan Kinglai Hygienic Materials Co Ltd
Priority date: 2022-04-06
Filing date: 2022-04-06
Publication date: 2024-04-02
Anticipated expiration: 2042-04-06
Also published as: CN114658861A

Abstract

The invention relates to the technical field of diaphragms, in particular to a diaphragm valve. The diaphragm valve comprises a valve body, a valve core, a cap and a valve rod. The inside of valve body has been seted up the runner of intaking, has given vent to anger runner and ladder groove, and the ladder groove is including the first cavity, second cavity and the third cavity of intercommunication in proper order, has first ladder face between first cavity and the second cavity. The air inlet of the air inlet runner can be communicated with the air outlet runner through the first cavity. The valve core comprises a valve seat, a connecting piece and a diaphragm, wherein the connecting piece is movably arranged in the stepped groove, the bottom of the connecting piece is provided with the valve seat, and the diaphragm is fixedly sleeved on the connecting piece and always pressed against the first stepped surface. The valve rod is arranged in the cap in a penetrating way in a sealing way and can axially move along the valve rod, the valve rod pushes the connecting piece to move towards the inside of the valve body, and the valve seat seals the air inlet; or the connecting piece is pulled to move to the outside of the valve body, and the valve seat opens the air inlet. The diaphragm valve can improve the pressure resistance and the service life.

Description

Diaphragm valve

Technical Field

The invention relates to the technical field of diaphragms, in particular to a diaphragm valve.

Background

A common vacuum diaphragm valve uses a valve stem to directly press a rubber diaphragm against a valve seat to shut off or turn on a valve body of a vacuum system.

In diaphragm valves, particularly high pressure resistant diaphragm valves, include a valve body having an inlet flow passage and an outlet flow passage therein, a valve seat fixedly disposed within the valve body and communicating with an inlet port of the inlet flow passage, a diaphragm, and a valve stem. When the valve rod pushes the diaphragm to block the valve seat, the diaphragm forms a seal with the valve seat and closes the air inlet of the air inlet flow channel, so that the air inlet flow channel and the air outlet flow channel are isolated from each other. When the valve rod pushes the diaphragm to be separated from the valve seat, the air inlet of the air inlet flow channel is opened, and the air inlet flow channel and the air outlet flow channel are communicated with each other. In the long-term use process of the diaphragm valve, the diaphragm and the valve seat are frequently contacted to cause abrasion of the valve seat, so that the sealing effect between the diaphragm and the valve seat is gradually weakened, the pressure resistance of the diaphragm valve is further affected, and the service life of the diaphragm valve is shortened.

Accordingly, a diaphragm valve is needed to solve the above-described problems.

Disclosure of Invention

The invention aims to provide a diaphragm valve, which is used for improving the sealing effect and pressure resistance of the diaphragm valve and prolonging the service life.

The technical scheme adopted by the invention is as follows:

a diaphragm valve, comprising:

the valve body is internally provided with an air inlet flow channel, an air outlet flow channel and a stepped groove, wherein the stepped groove comprises a first cavity, a second cavity and a third cavity which are sequentially communicated, and a first stepped surface is arranged between the first cavity and the second cavity; the air inlet of the air inlet flow channel can be communicated with the air outlet flow channel through the first cavity, and the third cavity penetrates through the top end of the valve body;

the valve core comprises a valve seat, a connecting piece and a diaphragm, wherein the connecting piece is movably arranged in the stepped groove, the valve seat is arranged at the bottom of the connecting piece, and the diaphragm is fixedly sleeved on the connecting piece and always pressed against the first stepped surface;

the cover cap is arranged in the third cavity in a sealing mode, the valve rod is arranged in the cover cap in a penetrating mode in a sealing mode and can move along the axial direction of the cover cap, and the valve rod is configured to push the connecting piece to move towards the inside of the valve body so that the valve seat seals the air inlet; or the connecting piece is pulled to move towards the outside of the valve body, so that the valve seat opens the air inlet.

As a preferable scheme, a guide hole is formed in the cap, the valve rod is in threaded connection with the guide hole, and a first limit groove is formed in the bottom of the valve rod;

the valve core further comprises a valve head, the valve head is mounted in the cap in a sealing mode, the bottom of the valve head is fixedly connected with the connecting piece, the top of the valve head is clamped in the first limiting groove, and the valve rod can rotate around the valve head in the axial direction relative to the valve head.

As a preferable scheme, the inner top wall of the first limit groove is concaved inwards to form a second limit groove, a ball is arranged in the second limit groove, and the ball protrudes out of the inner top wall of the first limit groove;

the top of valve head corresponds to set up the ball groove, when the top of valve head with first spacing groove joint is joined in marriage, the ball rotationally set up in the ball groove.

As a preferable scheme, the connecting piece comprises a stop block and a connecting rod, wherein the connecting rod is arranged at the upper end of the stop block, and the valve seat is arranged at the lower end of the stop block;

the bottom of the valve head is provided with a positioning hole, the connecting rod is in threaded connection with the positioning hole, and the valve head is abutted to the diaphragm.

Preferably, the number of the diaphragms is multiple, the diaphragms are sequentially stacked and sleeved on the connecting rod, and the diaphragms are connected with the connecting rod in a welding mode.

As the preferable scheme, the valve seat is annular, the stop block is correspondingly provided with an annular third limit groove, and the valve seat is clamped in the third limit groove and protrudes out of the bottom end of the stop block, so that the valve seat can seal the air inlet.

As a preferable scheme, the inner bottom wall of the first cavity is provided with a boss, the boss is provided with the air inlet, and the valve seat can be propped against the boss and is covered on the air inlet.

Preferably, the diaphragm valve further comprises:

the pressure ring is arranged in the second cavity, and the cap is propped against the upper end face of the pressure ring so that the lower end face of the pressure ring is propped against the diaphragm.

Preferably, the lower end surface of the pressing ring extends downwards from inside to outside along the radial direction of the pressing ring, so that the diaphragm deforms downwards from inside to outside along the radial direction of the pressing ring; the first step surface is an inclined surface matched with the deformed diaphragm.

Preferably, the valve body further includes:

the protection sleeve comprises a main valve body and an auxiliary valve body, wherein two auxiliary valve bodies are arranged at one end of the main valve body in a radial outward extending mode, the two auxiliary valve bodies are respectively provided with an air inlet flow passage and an air outlet flow passage, the main valve body is internally provided with a stepped groove extending along the axial direction of the main valve body, and the protection sleeve is sleeved at the top end of the main valve body.

The beneficial effects of the invention are as follows:

according to the diaphragm valve provided by the invention, when the valve rod pushes the connecting piece to move towards the inside of the valve body, the valve seat and the connecting piece synchronously move, so that the valve seat is abutted against the inner wall of the first cavity, the valve seat seals the air inlet of the air inlet flow passage, and the air inlet flow passage is disconnected with the air outlet flow passage. When the valve rod pushes the connecting piece to move towards the outside of the valve body, the valve seat and the connecting piece move synchronously, so that the valve seat is separated from contact with the inner wall of the first cavity, and the valve seat opens the air inlet of the air inlet flow channel, so that the air inlet flow channel is communicated with the air outlet flow channel through the first cavity. The diaphragm can take place elastic deformation at the reciprocating motion in-process of connecting piece for the diaphragm can support and press in first step face all the time, thereby separates first cavity and second cavity, has guaranteed the inside sealed effect of valve body. The valve seat, the connecting piece and the diaphragm form a whole, so that the mutual abrasion between the diaphragm and the valve seat is avoided, the good sealing effect between the valve seat and the valve body and between the diaphragm and the valve body is ensured, the pressure resistance of the diaphragm valve is improved, and the service life of the diaphragm valve is prolonged.

Drawings

FIG. 1 is a cross-sectional view of a diaphragm valve provided by an embodiment of the present invention;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

FIG. 3 is a cross-sectional view of a valve body provided by an embodiment of the present invention;

fig. 4 is a schematic structural view of a valve head according to an embodiment of the present invention.

The parts in the figures are named and numbered as follows:

1. a valve body; 11. a main valve body; 111. a first cavity; 1110. a boss; 112. a second cavity; 113. a third cavity; 110. a first step surface; 12. an auxiliary valve body; 121. an intake runner; 1210. an air inlet; 122. a gas outlet flow passage; 13. a protective sleeve; 2. a valve seat; 3. a connecting piece; 31. a stop block; 311. a third limit groove; 32. a connecting rod; 4. a membrane; 5. a valve head; 51. a spherical groove; 52. positioning holes; 53. a head; 54. a sealing part; 55. a stem portion; 6. capping; 61. a guide hole; 7. a valve stem; 71. a first limit groove; 72. the second limit groove; 8. a ball; 9. a compression ring; 10. and (3) sealing rings.

Detailed Description

In order to make the technical problems solved, the technical scheme adopted and the technical effects achieved by the invention more clear, the technical scheme of the invention is further described below by a specific embodiment in combination with the attached drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the drawings related to the present invention are shown.

In the description of the present invention, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "right", etc. orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the invention. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them.

The technical scheme of the invention is further described below by the specific embodiments with reference to the accompanying drawings.

In the long-term use process of the existing high-pressure diaphragm valve, the diaphragm and the valve seat are frequently contacted to cause abrasion of the valve seat, so that the sealing effect between the diaphragm and the valve seat is gradually weakened, the pressure resistance of the diaphragm valve is further affected, and the service life of the diaphragm valve is shortened.

In order to solve the above problems, as shown in fig. 1 to 3, the present embodiment discloses a diaphragm valve, which may be a high pressure diaphragm valve, having good pressure resistance.

Specifically, the diaphragm valve includes a valve body 1, a valve spool, a cap 6, and a valve stem 7. The inside of the valve body 1 is provided with an air inlet flow passage 121, an air outlet flow passage 122 and a stepped groove, wherein the stepped groove comprises a first cavity 111, a second cavity 112 and a third cavity 113 which are sequentially communicated, and a first stepped surface 110 is arranged between the first cavity 111 and the second cavity 112. The air inlet 1210 of the air inlet flow passage 121 can communicate with the air outlet flow passage 122 through the first cavity 111, and the third cavity 113 penetrates the top end of the valve body 1. The valve core comprises a valve seat 2, a connecting piece 3 and a diaphragm 4, wherein the connecting piece 3 is movably arranged in the stepped groove, the valve seat 2 is arranged at the bottom of the connecting piece 3, and the diaphragm 4 is fixedly sleeved on the connecting piece 3 and always abuts against the first stepped surface 110. The cap 6 is installed in the third cavity 113 in a sealing manner, the valve rod 7 is arranged in the cap 6 in a penetrating manner and can axially move along the cap, and the valve rod 7 can push the connecting piece 3 to move towards the inside of the valve body 1 so that the valve seat 2 can seal the air inlet 1210. Alternatively, the valve stem 7 pulls the connection member 3 to move to the outside of the valve body 1 so that the valve seat 2 opens the air inlet 1210.

In this embodiment, when the valve rod 7 pushes the connecting piece 3 to move toward the inside of the valve body 1, the valve seat 2 and the connecting piece 3 move synchronously, so that the valve seat 2 abuts against the inner wall of the first cavity 111, the valve seat 2 seals the air inlet 1210 of the air inlet channel 121, and the air inlet channel 121 is disconnected from the air outlet channel 122. When the valve rod 7 pushes the connecting member 3 to move to the outside of the valve body 1, the valve seat 2 and the connecting member 3 move synchronously, so that the valve seat 2 is out of contact with the inner wall of the first cavity 111, the valve seat 2 opens the air inlet 1210 of the air inlet flow passage 121, and the air inlet flow passage 121 communicates with the air outlet flow passage 122 through the first cavity 111. The membrane 4 can elastically deform in the process of the reciprocating movement of the connecting piece 3, so that the membrane 4 is always pressed against the first step surface 110, thereby separating the first cavity 111 from the second cavity 112, and ensuring the sealing effect inside the valve body 1. The valve seat 2, the connecting piece 3 and the diaphragm 4 of the embodiment form a whole, so that mutual abrasion between the diaphragm 4 and the valve seat 2 is avoided, good sealing effects between the valve seat 2 and the valve body 1 and between the diaphragm 4 and the valve body 1 are ensured, the pressure resistance of the diaphragm valve is improved, and the service life of the diaphragm valve is prolonged.

As shown in fig. 2 and 3, the valve body 1 includes a main valve body 11 and an auxiliary valve body 12, one end of the main valve body 11 extends radially outwardly with two auxiliary valve bodies 12, two auxiliary valve bodies 12 are respectively provided with an air inlet channel 121 and an air outlet channel 122, and a stepped groove extending axially is provided in the main valve body 11. The first cavity 111, the second cavity 112 and the third cavity 113 are sequentially arranged from bottom to top along the axial direction of the main valve body 11, and the third cavity 113 penetrates through the top end of the main valve body 11, so that the valve core, the cap 6 and the valve rod 7 are conveniently installed.

Specifically, as shown in fig. 1, the cap 6 has a U-shaped structure, and the outer periphery of the cap 6 is screwed with the inner wall of the third cavity 113. Meanwhile, a guide hole 61 is formed in the cap 6, and the valve rod 7 is in threaded connection with the guide hole 61. The valve rod 7 can be extended out of the cap 6 along the axial direction or into the cap 6 by manually screwing the valve rod 7, when the valve rod 7 extends into the cap 6, the connecting piece 3 can be pushed to move towards the inside of the valve body 1, and when the valve rod 7 extends out of the cap 6, the connecting piece 3 can be pulled to move towards the outside of the valve body 1.

The screwing operation of the valve rod 7 of the present embodiment may be performed manually or by an actuator such as a pneumatic arm. As shown in fig. 1 and 3, the diaphragm valve further includes a protective sleeve 13, and the protective sleeve 13 is sleeved on the top end of the main valve body 11. Specifically, the top periphery of the main valve body 11 has an external thread, and when the valve stem 7 is manually screwed, the protective sleeve 13 is screwed with the main valve body 11 to protect the integrity of the external thread of the main valve body 11. When the actuator is required to automatically screw the valve stem 7, the protective sleeve 13 is removed and the actuator is screwed into the main valve body 11.

As shown in fig. 1 and 4, the bottom of the valve rod 7 is provided with a first limit groove 71, the valve core further comprises a valve head 5, the valve head 5 is mounted in the cap 6 in a sealing manner, the bottom of the valve head 5 is fixedly connected with the connecting piece 3, the top of the valve head 5 is clamped in the first limit groove 71, and the valve rod 7 can rotate around the axial direction of the valve head 5 relative to the valve head 5.

Specifically, the valve head 5 includes a head 53, a sealing portion 54 and a stem portion 55 connected in sequence, the head 53 is of a columnar structure and has a conical head, the first limiting groove 71 is a T-shaped groove, and the head 53 of the valve head 5 is in clamping fit with the T-shaped groove. When the valve rod 7 is screwed, the valve head 5 can drive the connecting piece 3 to move along the axial direction of the valve rod 7, but cannot rotate along with the valve rod 7.

In this embodiment, the cap 6 and the valve stem 7, the cap 6 and the main valve body 11, and the valve head 5 and the cap 6 are all mounted in a sealing manner, so as to improve the sealing performance of the diaphragm valve. As shown in fig. 1, the outer periphery of the cap 6, the inner ring of the guide hole 61, and the outer periphery of the sealing portion 54 of the valve head 5 are each provided with an annular groove, each of which accommodates a seal ring 10 so as to maintain good sealing between the cap 6 and the main valve body 11, the valve stem 7, and the valve head 5, respectively.

In this embodiment, the air inlet channel 121 and the air outlet channel 122 are both communicated with the first cavity 111, the inner bottom wall of the first cavity 111 is provided with a boss 1110, and the boss 1110 is provided with an air inlet 1210 of the air inlet channel 121. When the valve seat 2 is pressed against the boss 1110 and covers the air inlet 1210, the air inlet 1210 is blocked by the valve seat 2, and the air inlet channel 121 is disconnected from the air outlet channel 122. When the valve seat 2 is out of contact with the boss 1110, the air intake 1210 is opened, and the air intake flow passage 121 is kept in communication with the air outlet flow passage 122.

As shown in fig. 1 and 4, the inner top wall of the first limiting groove 71 is concave to form a second limiting groove 72, the second limiting groove 72 is internally provided with a ball 8, and the ball 8 protrudes out of the inner top wall of the first limiting groove 71. The top of the valve head 5 is correspondingly provided with a ball groove 51. When the top of the valve head 5 is in clamping fit with the first limiting groove 71, the ball 8 is rotatably arranged in the ball groove 51. When screwing the valve rod 7 and stretching into in the block 6 to make connecting piece 3 move towards the inside of valve body 1, valve head 5 can twist 360 along the horizontal direction in first spacing groove 71, with the installation angle of fine setting valve head 5 and connecting piece 3, has improved the depth of parallelism of disk seat 2 and boss 1110, thereby has strengthened the laminating degree of disk seat 2 and boss 1110 and to the shutoff effect of air inlet 1210.

As shown in fig. 1 and 2, the connector 3 includes a stopper 31 and a link 32, the link 32 is provided at the upper end of the stopper 31, and the valve seat 2 is provided at the lower end of the stopper 31. The bottom of the valve head 5 is provided with a positioning hole 52, the connecting rod 32 is in threaded connection with the positioning hole 52, and the valve head 5 is abutted to the diaphragm 4. Specifically, the rod portion 55 of the valve head 5 is provided with a positioning hole 52, and the connecting rod 32 can extend into the positioning hole 52 and be in threaded connection with the positioning hole 52, so that the connecting piece 3 and the valve head 5 can be quickly installed. When the valve seat 2 is used for a long time and needs to be replaced, the connecting piece 3 and the valve head 5 are detachably installed, so that the disassembly, assembly and replacement of the connecting piece 3 can be rapidly completed.

In addition, when the valve head 5 is in threaded connection with the connecting piece 3, the rod part 55 of the valve head 5 can press the diaphragm 4 against the stop block 31, so that the diaphragm 4 and the connecting rod 32 are prevented from being welded, and the connection strength of the diaphragm 4 and the connecting piece 3 is further improved.

The number of the diaphragms 4 in the present embodiment is plural, the plural diaphragms 4 are sequentially stacked and sleeved on the connecting rod 32, and the plural diaphragms 4 can improve the compressive strength of the valve core. Meanwhile, the diaphragm 4 is welded with the connecting rod 32, so that the connection strength of the diaphragm 4 and the connecting piece 3 is improved, and good sealing between the diaphragm 4 and the connecting piece 3 can be ensured.

Specifically, the number of the diaphragms 4 of the present embodiment is four, and four diaphragms 4 are stacked together. The diaphragm 4 is provided with a central hole, the connecting rods 32 sequentially penetrate through the central holes of the four diaphragms 4, and the diaphragms 4 are abutted to the stop blocks 31 and are welded with the connecting rods 32 along the inner edges of the central holes. It will be appreciated that the specific number of diaphragms 4 may also be adapted according to design requirements.

As shown in fig. 1 and 2, the valve seat 2 is annular, the stop block 31 is correspondingly provided with an annular third limit groove 311, and the valve seat 2 is clamped in the third limit groove 311 and protrudes out of the bottom end of the stop block 31, so that the valve seat 2 can block the air inlet 1210. Specifically, the diaphragm 4 is welded on the connecting rod 32, and the valve seat 2 is clamped and fixed in the third limiting groove 311 of the stop block 31, so that the valve seat 2, the connecting piece 3 and the diaphragm 4 are connected into a whole and are matched with the valve body 1 to seal, and the pressure resistance of the diaphragm valve is improved.

It should be noted that, when the valve rod 7 drives the connecting piece 3 to move towards the inside or the outside of the valve body 1 through the valve head 5, the diaphragm 4 can elastically deform, so that the edge portion of the diaphragm 4 is always pressed against the first stepped surface 110, thereby ensuring the sealing isolation between the first cavity 111 and the second cavity 112, and avoiding the outside air or impurities from entering the air inlet channel 121 or the air outlet channel 122.

In order to ensure that the edge portion of the diaphragm 4 can always abut against the first step surface 110, as shown in fig. 1, the diaphragm valve further includes a pressure ring 9, where the pressure ring 9 is disposed in the second cavity 112, and the cap 6 abuts against the upper end surface of the pressure ring 9, so that the lower end surface of the pressure ring 9 abuts against the diaphragm 4. After the diaphragm valve is assembled, the compression ring 9 can be clamped in the first cavity 111, and the rod portion 55 of the valve head 5 penetrates through the inner ring of the compression ring 9 to be in threaded connection with the connecting rod 32 of the connecting piece 3, so that the valve body 1 is installed more compactly, the rod portion 55 of the valve head 5 is prevented from shaking greatly, and the moving stability of the connecting piece 3 is improved.

Preferably, as shown in fig. 2, the lower end surface of the pressing ring 9 extends obliquely downward from inside to outside in the radial direction thereof, so that the diaphragm 4 is deformed obliquely downward from inside to outside in the radial direction thereof. The first stepped surface 110 is an inclined surface adapted to the deformed diaphragm 4. Under the action of the pressing force of the pressing ring 9, the outer edge of the diaphragm 4 is curved in an arc shape, so that the edge of the diaphragm 4 is tightly attached to the first step surface 110, the sealing effect of the diaphragm 4 is enhanced, the first cavity 111 and the second cavity 112 are separated, and a good sealing effect in the first cavity 111 is ensured.

The above embodiments merely illustrate the basic principle and features of the present invention, and the present invention is not limited to the above embodiments, but may be varied and altered without departing from the spirit and scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A diaphragm valve, comprising:

the valve comprises a valve body (1), wherein an air inlet flow channel (121), an air outlet flow channel (122) and a stepped groove are formed in the valve body, the stepped groove comprises a first cavity (111), a second cavity (112) and a third cavity (113) which are sequentially communicated, and a first stepped surface (110) is arranged between the first cavity (111) and the second cavity (112); an air inlet (1210) of the air inlet flow channel (121) can be communicated with the air outlet flow channel (122) through the first cavity (111), and the third cavity (113) penetrates through the top end of the valve body (1);

the valve core comprises a valve seat (2), a connecting piece (3) and a diaphragm (4), wherein the connecting piece (3) is movably arranged in the stepped groove, the valve seat (2) is arranged at the bottom of the connecting piece (3), and the diaphragm (4) is fixedly sleeved on the connecting piece (3) and always pressed against the first stepped surface (110);

a cap (6) and a valve rod (7), wherein the cap (6) is hermetically installed in the third cavity (113), the valve rod (7) is hermetically penetrated in the cap (6) and can move along the axial direction of the valve rod, and the valve rod (7) is configured to push the connecting piece (3) to move towards the inside of the valve body so as to enable the valve seat (2) to seal the air inlet (1210); or, pulling the connecting piece (3) to move to the outside of the valve body so that the valve seat (2) opens the air inlet (1210);

a guide hole (61) is formed in the cap (6), the valve rod (7) is in threaded connection with the guide hole (61), and a first limit groove (71) is formed in the bottom of the valve rod (7);

the valve core further comprises a valve head (5), the valve head (5) is arranged in the cap (6) in a sealing mode, the bottom of the valve head (5) is fixedly connected with the connecting piece (3), the top of the valve head (5) is clamped in the first limit groove (71), and the valve rod (7) can rotate around the axial direction of the valve head (5) relative to the valve head (5);

the inner top wall of the first limit groove (71) is concaved inwards to form a second limit groove (72), a ball (8) is arranged in the second limit groove (72), and the ball (8) protrudes out of the inner top wall of the first limit groove (71);

the top of the valve head (5) is correspondingly provided with a spherical groove (51), and when the top of the valve head (5) is in clamping fit with the first limit groove (71), the ball (8) is rotatably arranged in the spherical groove (51);

the diaphragm valve further includes: the pressure ring (9) is arranged in the second cavity (112), and the cap (6) is propped against the upper end surface of the pressure ring (9) so as to enable the lower end surface of the pressure ring (9) to be propped against the diaphragm (4);

the lower end surface of the pressing ring (9) extends downwards from inside to outside along the radial direction of the pressing ring so as to enable the diaphragm (4) to deform downwards from inside to outside along the radial direction of the diaphragm; the first stepped surface (110) is an inclined surface which is matched with the deformed diaphragm (4).

2. The diaphragm valve according to claim 1, characterized in that the connecting piece (3) comprises a stopper (31) and a connecting rod (32), the connecting rod (32) being provided at the upper end of the stopper (31), the valve seat (2) being provided at the lower end of the stopper (31);

the bottom of the valve head (5) is provided with a positioning hole (52), the connecting rod (32) is in threaded connection with the positioning hole (52), and the valve head (5) is abutted to the diaphragm (4).

3. The diaphragm valve according to claim 2, wherein the number of the diaphragms (4) is plural, the plural diaphragms (4) are sequentially stacked and sleeved on the connecting rod (32), and the diaphragms (4) are welded with the connecting rod (32).

4. The diaphragm valve according to claim 2, wherein the valve seat (2) is annular, the stopper (31) is correspondingly provided with an annular third limit groove (311), and the valve seat (2) is clamped in the third limit groove (311) and protrudes out of the bottom end of the stopper (31), so that the valve seat (2) can seal the air inlet (1210).

5. The diaphragm valve of claim 4, wherein the inner bottom wall of the first cavity (111) has a boss (1110), the boss (1110) is provided with the air inlet (1210), and the valve seat (2) can be pressed against the boss (1110) and is covered on the air inlet (1210).

6. The diaphragm valve of claim 1 wherein the valve body further comprises:

the protection sleeve (13), valve body (1) is including main valve body (11) and vice valve body (12), the one end of main valve body (11) has two along its radial outside extension vice valve body (12), two vice valve body (12) are equipped with respectively inlet channel (121) with flow channel (122) give vent to anger, set up in main valve body (11) along its axial extension's ladder groove, protection sleeve (13) cover is located the top of main valve body (11).