CN114923027A

CN114923027A - Stop valve, assembly method of stop valve and valve body assembly

Info

Publication number: CN114923027A
Application number: CN202210587934.4A
Authority: CN
Inventors: 韩利民; 王于冲; 李文园; 都洪阳
Original assignee: Henan Spake Instrument Technology Co ltd
Current assignee: Henan Spake Instrument Technology Co ltd
Priority date: 2022-05-27
Filing date: 2022-05-27
Publication date: 2022-08-19

Abstract

The invention discloses a stop valve which comprises a valve needle, a locking nut, a hand wheel and a valve core assembly, wherein the valve core assembly comprises a valve core body, a sealing gasket, an external sealing assembly and an internal sealing assembly, the valve core body comprises an outer wall part, an inner cavity and a rear end face, a fluid inlet pipeline and a fluid outlet pipeline are arranged on the outer wall part, the sealing gasket and the external sealing assembly are detachably arranged on the outer wall part, and the internal sealing assembly is detachably arranged in the inner cavity. The invention also provides a valve body assembly, which comprises an external valve body and the stop valve, wherein one end of the stop valve is detachably arranged in the external valve body. The invention can replace and maintain the aged or damaged parts without replacing all parts of the valve core body, the stop valve or the valve body assembly, thereby reducing the maintenance cost.

Description

Stop valve, assembly method of stop valve and valve body assembly

Technical Field

The invention relates to the field of valve bodies, in particular to a stop valve, an assembly method of the stop valve and a valve body assembly.

Background

As shown in fig. 1, the valve body assembly includes a valve body 45 and a stop valve composed of a valve core body 40, a sealing gasket 41, an internal sealing assembly 42, an external sealing assembly 43, a lock nut 44 and a valve needle 46. In the above-mentioned stop valve, the built-in sealing assembly 43 belongs to a fragile and aging-prone component, and when it is damaged or aged, it needs to be replaced, otherwise, the use effect of the stop valve will be affected. However, since the built-in seal assembly 43 is located inside the cartridge body 40 and is sleeved at a position close to the front end of the needle 46, there are disadvantages in that it is inconvenient to replace it and maintenance is complicated.

Disclosure of Invention

Aiming at the defects in the problems, the invention provides a stop valve and a valve body assembly which are convenient for replacing aged or damaged built-in sealing assemblies and other components:

a stop valve comprises a valve needle, a locking nut, a hand wheel and a valve core assembly, wherein the valve core assembly comprises a valve core body, a sealing gasket, an external sealing assembly and a built-in sealing assembly, the valve core body comprises an outer wall portion, an inner cavity and a rear end face, a fluid inlet pipeline and a fluid outlet pipeline are arranged on the outer wall portion, the sealing gasket and the external sealing assembly are detachably arranged on the outer wall portion, and the built-in sealing assembly is detachably arranged in the inner cavity.

Preferably, in a stop valve, the outer wall portion includes a lower end surface, the fluid inlet pipeline and the fluid outlet pipeline both penetrate through the inside of the lower end surface and are communicated with the inner cavity, the lower end surface is provided with an annular protrusion butted with the fluid inlet pipeline, the sealing gasket is detachably sleeved inside the annular protrusion, the front end of the sealing gasket is located outside the annular protrusion, the sealing gasket is of an annular structure, a hollow area of the sealing gasket is communicated with the fluid inlet pipeline, and the sealing gasket, the annular protrusion, the fluid inlet pipeline, the inner cavity and the built-in sealing assembly are coaxially arranged;

the outer wall portion comprises a side wall surface, the detachable sleeve of the external sealing assembly is arranged in a clamping groove formed in the circumferential direction of the side wall surface, the outer end face of the external sealing assembly is located on the outer side of the clamping groove, the external sealing assembly is composed of a rubber sealing ring a and a tetrafluoro gasket a which are stacked in sequence, the outer end face of the rubber sealing ring a and the outer end face of the tetrafluoro gasket a are located on the outer side of the clamping groove, a first thread portion and a second thread portion are further arranged on the outer side of the side wall surface, the first thread portion is close to the external sealing assembly, and the second thread portion is close to the rear end face.

Preferably, in a stop valve, the inner cavity includes a rear cavity, the built-in seal assembly is detachably disposed in the rear cavity, the front end of the built-in seal assembly contacts with the front end of the rear cavity, and the tail end of the built-in seal assembly does not extend to the outside of the rear end face, the built-in seal assembly includes a copper gasket a, a tetrafluoro gasket b, a rubber seal ring b and a copper gasket b which are sequentially stacked, the front end of the copper gasket a contacts with the front end of the rear cavity, and the tail end of the copper gasket b is close to the rear end face;

the inner cavity further comprises a front cavity communicated with the rear cavity, and multiple threads are distributed on the inner wall surface of the front cavity.

Preferably, in a stop valve, the dismantled and assembled cover of lock nut is established the outside of outer wall portion, and with rear end face looks butt, the inside of needle runs through built-in seal assembly inside back and the screw-thread fit in the interior cavity, and moves between the inside of fluid inlet pipeline and interior cavity, the terminal of needle run through in lock nut's inside back with hand wheel connection.

Preferably, in a stop valve, the needle is including the needle front end, the needle middle part and the needle end that connect gradually, the needle middle part pass built-in seal assembly after with screw-thread fit in the interior cavity is connected, the needle front end can move between fluid inlet pipeline inside and the interior cavity, the terminal end of needle end is located the outside of rear end face, the outer wall surface at needle middle part be equipped with screw thread portion of screw-thread fit in the interior cavity.

The invention also provides an assembly method of the stop valve, which is characterized by comprising the following steps of:

the sealing gasket is detachably arranged in the convex part of the lower end surface of the valve core body;

detachably sleeving an external sealing assembly inside a clamping groove formed in the valve core body along the circumferential direction of the side wall surface;

placing the valve needle inside the inner cavity of the valve core body, so that the front end of the valve needle corresponds to the fluid inlet pipeline and can move between the inside of the fluid inlet pipeline and the inner cavity;

sleeving the built-in sealing component on the tail end of the valve needle, and detachably placing the built-in sealing component in the rear cavity;

the locking nut is detachably sleeved on the outer side of the side wall surface and is abutted against the rear end surface;

and connecting a hand wheel with the tail end of the valve needle to complete the assembly of the stop valve.

The invention also provides a valve body assembly, which comprises an external valve body and the stop valve, wherein one end of the stop valve is detachably arranged in the external valve body;

the external valve body comprises a stop valve interface, and a fluid injection pipeline and a fluid discharge pipeline which are respectively butted and communicated with the stop valve interface;

the lower end face of the valve core assembly is provided with a fluid inlet pipeline communicated with the fluid injection pipeline and a fluid outlet pipeline communicated with the fluid discharge pipeline;

the external valve body is also respectively provided with a fluid injection interface communicated with the fluid injection pipeline and a fluid discharge interface communicated with the fluid discharge pipeline;

the lower end face is detachably provided with a sealing gasket, the sealing gasket is abutted against the bottom wall of the stop valve port and is positioned between the fluid inlet pipeline and the fluid injection pipeline;

and an intermediate pipeline is formed between the lower end surface and the bottom wall of the stop valve port through the sealing gasket, and is respectively butted and communicated with the fluid discharge pipeline and the fluid outlet pipeline.

The invention has the beneficial effects that:

1. when any one of the sealing gasket, the external sealing assembly and the internal sealing assembly is aged or damaged, only a specified sealing part needs to be replaced, all parts of the valve core body do not need to be replaced, the valve core body in the stop valve is convenient to maintain, and the maintenance cost of the valve core body in the stop valve can be reduced;

2. because the valve needle, the locking nut, the hand wheel and the valve core body in the stop valve are assembled in a detachable movable connection mode, if any one part is aged or damaged, only the appointed part needs to be replaced, all parts of the stop valve do not need to be replaced, the stop valve is convenient to maintain, and the maintenance cost of the stop valve can be reduced;

3. the stop valve adopts dismantled and assembled mode and outside valve body threaded connection, when arbitrary one of the two breaks down, only need dismantle the back change trouble part can, need not to change whole parts of valve body subassembly, be convenient for maintain the valve body subassembly to can reduce the cost of maintenance of valve body subassembly.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without inventive labor.

FIG. 1 is an internal structural view of a prior art valve body assembly;

FIG. 2 is a block diagram of a shut-off valve according to the present invention;

FIG. 3 is a cross-sectional view of FIG. 2;

FIG. 4 is a block diagram of the valve spool assembly of FIG. 2;

FIG. 5 is a cross-sectional view of FIG. 4;

FIG. 6 is an exploded view of FIG. 4;

FIG. 7 is a cross-sectional view of FIG. 6;

FIG. 8 is a block diagram of the check valve of the present invention;

FIG. 9 is a cross-sectional view of FIG. 8;

FIG. 10 is a block diagram of a pressure maintaining valve of the present invention;

FIG. 11 is a cross-sectional view of FIG. 10;

in the figure: 1-a valve core body; 100-lower end face; 1001-fluid inlet line; 1002-a fluid outlet line; 102-a side wall face; 1021-a first threaded portion; 1022 — a second threaded portion; 103-front cavity; 104-rear cavity; 1041-a stepped portion; 105-an annular projection; 106-a sealing gasket; 107-external sealing assembly; 1071-rubber seal ring a; 1072-tetrafluoro pad a; 108-built-in seal assembly; 1081-copper pad a; 1082-tetrafluoro pad b; 1083-rubber seal ring b; 1084-copper pad b; 109-card slot; 110-a rear end face;

21-a valve needle; 211-valve needle front end; 212-valve needle middle; 213-valve needle tip; 22-a locking nut; 23-a hand wheel;

31-an outer valve body; 32-stop valve interface; 33-fluid injection interface; 331-fluid injection line; 34-a fluid outlet interface; 341-fluid discharge line; 35-intermediate piping; 36-an inlet connection; 37-an outlet interface;

40-a valve core body; 41-a sealing gasket; 42-built-in seal assembly; 43-external sealing component; 44-a locking nut; 45-a valve body; 46-a valve needle.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 2-7, the present invention provides a stop valve, which includes a valve needle 21, a lock nut 22, a hand wheel 23, and a valve core assembly, wherein the valve core assembly includes a valve core body 1, a sealing gasket 106, an external sealing assembly 107, and an internal sealing assembly 108.

The valve body 1 includes a lower end surface 100, a side wall surface 102, an open rear end surface 110, and a seal assembly.

An inner cavity formed by a front cavity 103 and a rear cavity 104 which are communicated with each other is arranged in the valve core body 1. The front cavity 103 and the rear cavity 104 are coaxially arranged, the front cavity 103 and the rear cavity are both cylindrical structures, and the diameter of the front cavity 103 is smaller than that of the rear cavity 104.

The front end of the rear cavity 104 forms a step 1041, and the rear end extends to the position of the rear end surface 110.

The sealing assembly comprises a sealing gasket 106, an external sealing assembly 107 and an internal sealing assembly 108.

The built-in seal assembly 108 is detachably disposed in the rear cavity 104, a front end of the built-in seal assembly 108 contacts the step 1041, and a tail end of the built-in seal assembly 108 is close to the rear end surface 110 of the valve plug body 1 and does not extend to an outer side of the rear end surface 110.

The built-in sealing assembly 108 comprises a copper pad a1081, a tetrafluoro pad b1082, a rubber sealing ring b1083 and a copper pad b1084 which are sequentially stacked, wherein the front end of the copper pad a1081 is in contact with the step 1041, and the tail end of the copper pad b1084 is close to the rear end face 110 of the valve core body 1.

Because the built-in sealing component is assembled in the rear cavity in a movable connection mode, when the built-in sealing component is aged or damaged, the built-in sealing component only needs to be replaced after being taken out of the rear cavity, all parts of the valve core body do not need to be replaced, and the maintenance cost of the valve core can be reduced.

Multiple threads (not shown) are distributed on the inner wall surface of the front cavity 103. The multiple threads cooperate with multiple threads provided on the outer wall surface of the valve needle such that the valve needle moves within the front cavity of the cartridge body and the inner portion of the built-in seal assembly 108 in cooperation with the multiple threads.

A fluid inlet pipe 1001 and a fluid outlet pipe 1002 penetrating the lower end surface 100 and communicating with the front cavity 103 are provided.

The fluid inlet pipe 1001 and the fluid outlet pipe 1002 extend from the front end of the lower end surface 100 to the rear end of the lower end surface 100.

The fluid medium can be fed into the interior of the front cavity 103 through the fluid inlet line 1001 and can be discharged to the outside of the front cavity 103 through the fluid outlet line 1002.

In this embodiment, the number of the fluid outlet pipes 1002 is two, and the positions of the fluid outlet pipes 1002 are correspondingly located on two sides of the fluid outlet pipes 1002.

An annular protrusion 105 is provided at the front end of the lower end surface 100 to correspond to and abut against the fluid inlet pipe 1001.

The sealing gasket 106 is removably disposed inside the annular projection 105, and the lower end surface 100 thereof is located outside the annular projection 105.

Gasket seal 106 is an annular structure having a hollow region in communication with fluid inlet conduit 1001, and the hollow region is coaxially disposed with fluid inlet conduit 1001, front cavity 103, rear cavity 104, and internal seal assembly 108.

Because the sealing gasket adopts the swing joint mode to be assembled in cyclic annular arch, when the sealing gasket takes place ageing or the damage condition, only need with it by cyclic annular arch take out the back change can, and need not to change whole parts of case body, can reduce the cost of maintenance to the case.

A locking groove 109 is formed on the outer wall surface of the side wall surface 102 along the circumferential direction of the side wall surface 102 and is positioned close to the lower end surface 100.

The external sealing component 107 is detachably sleeved inside the clamping groove 109, and the outer end surface of the external sealing component 107 is located outside the clamping groove 109.

The external sealing assembly 107 is composed of a rubber sealing ring a1071 and a tetrafluoro gasket a1072 which are sequentially stacked, wherein the outer end face of the rubber sealing ring a1071 and the outer end face of the tetrafluoro gasket a1072 are both located outside the clamping groove 109.

Because external seal assembly adopts the swing joint mode to be assembled in the draw-in groove, when external seal assembly takes place ageing or the damage condition, only need with it by take out in the draw-in groove after change can, and need not to change all parts of case body, can reduce the cost of maintenance to the case.

In addition, a first screw portion 1021 and a second screw portion 1022 are further disposed on the outer side of the side wall surface 102, the first screw portion 1021 is located near the outboard sealing component 107, and the second screw portion 1022 is located near the rear end surface 110. The first thread portion 1021 facilitates assembly of the valve cartridge body to the outer valve body, and the second thread portion 1022 facilitates nesting of an outer lock nut on the outside of the side wall surface.

The bottom end of the locking nut 22 is open structure, the top end is provided with an opening, and the interior is hollow structure. A threaded portion is distributed in an inner portion of the side wall surface of the lock nut 22, and the lock nut 22 is detachably fitted on an outer side of the side wall surface 102 by the threaded portion and the second threaded portion 1022. Wherein the top end of the locking nut 22 abuts against the rear end face 110 and the built-in seal assembly 108, and the opening is coaxially arranged with the rear cavity 104.

The valve needle 21 comprises a valve needle front end 211, a valve needle middle part 212 and a valve needle tail end 213 which are connected in sequence, and the valve needle front end 211 and the valve needle middle part 212 can be placed in the front cavity 103 after passing through the built-in sealing component 108.

Valve needle forward end 211 is a needle tip structure that causes fluid inlet conduit 1001 to assume a closed position when a portion of the needle tip is disposed within fluid inlet conduit 1001 and causes fluid inlet conduit 1001 to assume an open position when a portion of the needle tip is disposed outside fluid inlet conduit 1001.

The outer wall surface of the needle middle part 212 is provided with a threaded part which is matched with multiple threads in the front cavity 103. The middle needle part 212 cooperates with the multiple threads by means of the threaded portion, such that the middle needle part moves inside the front cavity, thereby bringing a part of the front needle end 211 to move inside the fluid inlet conduit 1001 or to move outside the fluid inlet conduit 1001.

One part of the needle tail end 213 is arranged in the built-in sealing component 108, and the other part of the needle tail end passes through the lock nut 22 sleeved on the outer side of the valve core body 1 and then is connected with the hand wheel 23.

The portion of the valve needle tip end 213 disposed inside the built-in seal assembly 108 is in close contact with the built-in seal assembly 108, so that the pressure medium in the front cavity can be prevented from being overflowed from the contact area between the valve needle tip end 213 and the built-in seal assembly 108.

When a portion of the needle tip is disposed outside of the fluid inlet line 1001, the fluid inlet line 1001 is caused to assume an open state. The oily pressure medium can be fed into the front chamber 103 through the fluid inlet line 1001, and then fed out to the outside of the front chamber 103 through the two fluid outlet lines 1002.

When the oily pressure medium is input into the front cavity 103, the lubricating performance between the thread part on the outer wall surface of the valve needle middle part 212 and the multiple threads in the front cavity 103 can be improved, so that the valve needle middle part 212 moves more smoothly in the front cavity 103.

In addition, the invention also provides an assembly method of the stop valve, which comprises the following steps:

detachably sleeving the external sealing component in a clamping groove which is formed in the valve core body along the circumferential direction of the side wall surface;

connecting a hand wheel with the tail end of the valve needle to complete the assembly of the stop valve

As shown in fig. 8 and 9, the present invention provides a valve body assembly, which is a return check valve, and includes an external valve body and a stop valve as shown in fig. 2 to 7, wherein one end of the stop valve is detachably disposed inside the external valve body.

The external valve body 31 includes a shut-off valve port 32, a fluid injection line 331 and a fluid discharge line 341 butted thereto and communicated therewith, respectively, a fluid injection port 33 communicated with the fluid injection line 331, and a fluid discharge port 34 communicated with the fluid discharge line 341.

In this embodiment, the fluid injection port 33 is detachably screwed to the inlet connector 36, so that the fluid line inside the inlet connector 36 communicates with the fluid injection line 331.

The inlet port 36 is located on one side of the outer valve body 31, and the fluid discharge port 34 is located on the lower end wall surface of the outer valve body 31.

In addition, one end of the stop valve is arranged in the stop valve interface 32 of the external valve body in a detachable threaded connection mode.

A screw thread portion is provided on a side wall surface of the stop valve interface 32, and the screw thread portion is engaged with a first screw thread portion 1021 on the valve body 1 in the stop valve.

Further, an external seal unit 107 is fitted to the side wall surface 10 of the valve body 1 and abuts against the side wall surface of the stop valve port 32. The sealing performance between the valve core body and the stop valve interface can be improved through the external sealing assembly.

When the valve core body 1 in the stop valve is placed inside the stop valve port 32, the sealing gasket 106 detachably disposed on the lower end surface 100 abuts against the bottom wall of the stop valve port 32, and is located between the fluid inlet pipeline 1001 and the fluid injection pipeline 331, so that the fluid inlet pipeline 1001 is communicated with the fluid injection pipeline 331.

The intermediate line 35 is also formed between the lower end face 100 and the bottom wall of the shut-off valve port 32 by the sealing gasket 106, and the fluid discharge line 341 and the two fluid outlet lines 1002 communicate by forming the intermediate line 35.

The sealing performance between the fluid inlet line 1001 and the fluid injection line 331 can be increased by the gasket seal 106.

When the fluid inlet line is in an open state, the oily pressure medium is input into the front cavity 103 through the inlet joint 36, the fluid injection line 331 and the fluid inlet line 1001, and then is discharged to the outside of the valve body assembly through the two fluid outlet lines 1002, the middle line 35, the fluid discharge line 341 and the fluid discharge port 34.

As shown in fig. 10 and 11, the present invention provides a valve body assembly, which is a pressure maintaining valve, and includes an external valve body 31 and a stop valve as shown in fig. 2 to 7, wherein one end of the stop valve is detachably disposed inside the external valve body 31.

In this embodiment, the fluid injection port 33 is detachably screwed to the inlet connector 36, so that the fluid line inside the inlet connector 36 communicates with the fluid injection line 331. The fluid outlet port 34 is detachably screwed to the outlet connector 37, so that the fluid line inside the outlet connector 37 communicates with the fluid outlet line 341.

The inlet joint 36 and the outlet joint 37 are located on two sides of the outer valve body 31 and correspond to each other in position.

In addition, one end of the stop valve is disposed inside the stop valve port 32 of the outer valve body in a detachable threaded connection.

The side wall surface of the stop valve interface 32 is provided with a thread part which is matched with a first thread part 1021 on the valve core body 1 in the stop valve.

When the fluid inlet line is in an open state, the oily pressure medium is input into the front cavity 103 through the inlet joint 36, the fluid injection line 331 and the fluid inlet line 1001, and then discharged to the outside of the valve body assembly through the two fluid outlet lines 1002, the intermediate line 35, the fluid discharge line 341 and the fluid discharge port 34.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best understand the invention for and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A stop valve, characterized by: the valve core assembly comprises a valve needle (21), a locking nut (22), a hand wheel (23) and a valve core assembly, wherein the valve core assembly comprises a valve core body (1), a sealing gasket (106), an external sealing assembly (107) and a built-in sealing assembly (108), the valve core body (1) comprises an outer wall part, an inner cavity and a rear end face (110), a fluid inlet pipeline (1001) and a fluid outlet pipeline (1021) are formed in the outer wall part, the sealing gasket (106) and the external sealing assembly (107) are detachably arranged on the outer wall part, and the built-in sealing assembly (108) is detachably arranged in the inner cavity.

2. A shut-off valve as claimed in claim 1, wherein: the outer wall part comprises a lower end face (100), the fluid inlet pipeline (1001) and the fluid outlet pipeline (1021) both penetrate through the interior of the lower end face (100) and are communicated with the inner cavity, an annular bulge (105) butted with the fluid inlet pipeline (1001) is arranged on the lower end face (100), the sealing gasket (106) is detachably sleeved in the annular bulge (105), the front end of the sealing gasket is positioned on the outer side of the annular bulge (105), the sealing gasket (106) is of an annular structure, the hollow area of the sealing gasket (106) is communicated with the fluid inlet pipeline (1001) and is coaxially arranged with the annular bulge (105), the fluid inlet pipeline (1001), the inner cavity and the built-in sealing assembly (108);

the outer wall portion comprises a side wall surface (102), the external sealing assembly (107) is detachably sleeved in a clamping groove (109) formed in the circumferential direction of the side wall surface (102), the outer end face of the external sealing assembly (107) is located on the outer side of the clamping groove (109), the external sealing assembly (107) is composed of a rubber sealing ring a (1071) and a tetrafluoro pad a (1072) which are stacked in sequence, the outer end face of the rubber sealing ring a (1071) and the outer end face of the tetrafluoro pad a (1072) are located on the outer side of the clamping groove (109), a first thread portion (1021) and a second thread portion (1022) are further arranged on the outer side of the side wall surface (102), the position of the first thread portion (1021) is close to the external sealing assembly (107), and the position of the second thread portion (1022) is close to the position of the rear end face (110).

3. A shut-off valve as claimed in claim 2, wherein: the inner cavity comprises a rear cavity (104), the built-in sealing assembly (108) is detachably arranged in the rear cavity (104), the front end of the built-in sealing assembly (108) is in contact with the front end of the rear cavity (104), the tail end of the built-in sealing assembly (108) does not extend to the outer side of the rear end face (110), the built-in sealing assembly (108) comprises a copper pad a (1081), a polytetrafluoroethylene pad b (1082), a rubber sealing ring b (1083) and a copper pad b (1084) which are sequentially stacked, the front end of the copper pad a (1081) is in contact with the front end of the rear cavity (104), and the tail end of the copper pad b (1084) is close to the rear end face (110);

the inner cavity further comprises a front cavity (103) communicated with the rear cavity (104), and multiple threads are distributed on the inner wall surface of the front cavity (103).

4. A shut-off valve as claimed in any one of claims 1 to 3, wherein: the detachable sleeve of lock nut (22) is established the outside of outer wall portion, and with rear end face (110) looks butt, the inside of needle (21) is run through built-in seal assembly (108) inside back and the screw-thread fit in the interior cavity, and moves between the inside of fluid inlet pipeline and interior cavity, the end of needle (21) run through in the inside of lock nut (22) the back be connected with hand wheel (23).

5. A shut-off valve as claimed in claim 4, wherein: needle (21) including needle front end (211), needle middle part (212) and the needle end (213) that connect gradually, needle middle part (212) pass built-in seal assembly (108) back with screw-thread fit in the interior cavity is connected, needle front end (211) can move between fluid inlet pipeline (1001) inside and interior cavity, the terminal of needle end (213) is located the outside of rear end face (110), the outer wall face of needle middle part (212) be equipped with screw thread portion of screw-thread fit in the interior cavity.

6. A method of assembling a shut-off valve, comprising the steps of:

s1, detachably placing a sealing gasket (106) in a shape bulge (105) of the middle and lower end surface (100) of the valve core body (1);

s2, detachably sleeving an external sealing component (107) in a clamping groove (109) formed in the valve core body (1) along the circumferential direction of the side wall surface (102);

s3, placing the valve needle (21) in the inner cavity of the valve core body (1) to enable the front end (211) of the valve needle to correspond to the fluid inlet pipeline (1001) and move between the inner cavity and the fluid inlet pipeline (1001);

s4, sleeving the built-in sealing assembly (108) on the tail end (213) of the valve needle, and detachably placing the built-in sealing assembly in the rear cavity (104);

s5, detachably sleeving the locking nut (22) on the outer side of the side wall surface (102) and abutting against the rear end surface (110);

and S6, connecting the hand wheel (23) with the tail end (213) of the valve needle to complete the assembly of the stop valve.

7. A valve body assembly characterized by: comprising an outer valve body (31) and a shut-off valve according to any of claims 1 to 5, one end of the shut-off valve being removably placed inside the outer valve body (31);

the external valve body (31) comprises a stop valve interface (32) and a fluid injection pipeline (331) and a fluid discharge pipeline (341) which are respectively butted with and communicated with the stop valve interface;

the lower end surface (100) of the valve core assembly is provided with a fluid inlet pipeline (1001) communicated with the fluid injection pipeline (331) and a fluid outlet pipeline (1021) communicated with the fluid discharge pipeline (341);

the external valve body (31) is also provided with a fluid injection interface (33) communicated with the fluid injection pipeline (331) and a fluid discharge interface (34) communicated with the fluid discharge pipeline (341) respectively;

a sealing gasket (106) is detachably arranged on the lower end surface (100), the sealing gasket (106) is abutted against the bottom wall of the stop valve interface (32) and is positioned between the fluid inlet pipeline (1001) and the fluid injection pipeline (331);

an intermediate pipeline (35) is formed between the lower end surface (100) and the bottom wall of the stop valve interface (32) through the sealing gasket (106), and is respectively butted and communicated with the fluid discharge pipeline (341) and the fluid outlet pipeline (1021).