CN107191661B

CN107191661B - Stop valve

Info

Publication number: CN107191661B
Application number: CN201710502372.8A
Authority: CN
Inventors: 周泰鹍; 蔡京淮; 胡庆节; 沈韬
Original assignee: Chengdu Guoguang Electric Co Ltd
Current assignee: Chengdu Guoguang Electric Co Ltd
Priority date: 2017-06-27
Filing date: 2017-06-27
Publication date: 2023-03-14
Anticipated expiration: 2037-06-27
Also published as: CN107191661A

Abstract

The stop valve includes: a valve body; the permanent magnet operating mechanism comprises a shell arranged in the valve body, a coil and a permanent magnet which are arranged in the shell, and a movable iron core movably sleeved in the coil and the permanent magnet; the valve rod comprises a first end extending into the valve body and a second end extending out of the valve body and penetrating through the movable iron core; the first force transmission structure is arranged on the valve rod; the elastic device is used for connecting the valve rod and the movable iron core, preventing the movable iron core from moving towards the second end direction and storing energy, applying acting force to the valve rod in the process of preventing the movable iron core from moving towards the second end direction so as to enable the valve rod to move towards the direction far away from the valve body, and applying acting force to the movable iron core after energy is stored so as to generate the initial speed of the movable iron core moving towards the first force transmission structure direction; the movable iron core can reciprocate along the valve rod; when the movable iron core is abutted to the first force transmission structure, the movable iron core applies an acting force for pushing the valve rod to move towards the valve body direction to the first force transmission structure. It can maintain working state without continuous power-on, and has quick action response and simple structure.

Description

Stop valve

Technical Field

The invention relates to a valve, in particular to a stop valve.

Background

The stop valve is widely applied to a fluid conveying system as a control part in the field of pressure pipelines, plays a role in changing the section of a passage and the flowing direction of fluid, has the functions of diversion, cutoff, throttling, non-return, flow splitting, overflow pressure relief and the like, and is an irreplaceable actuator. With the development of industrial control technology, the remote control and management of the pressure pipeline are more intelligent, and higher requirements are put forward on the reliability, safety, operability, energy conservation and the influence on the temperature of fluid on the stop valve. There are still some problems with the present electromagnetic shut-off valves used to perform remote control of the pressure line.

(1) Because the electromagnetic cut-off valve still needs less current to maintain the working state after being electrified or realizes self-holding in a more complex mode, an electromagnetic driving mechanism of the electromagnetic cut-off valve becomes an obvious heat source after working, and the fault point is increased due to the complex self-holding structure. If the stop valve becomes a heat source, uncontrollable influence can be generated on fluid sensitive to temperature change, such as the fields of chemical industry, low temperature and the like.

(2) The traditional normally closed electromagnetic stop valve generates suction force on the movable iron core through coil energization and excitation, the movable iron core moves upwards to open the stop valve after overcoming the elastic force of the reset spring, the movable iron core moves downwards to close the stop valve under the action of the elastic force released by the reset spring and the dead weight of the movable iron core after power failure, and the normally open type electromagnetic stop valve is not closed. The action response of the stop valve is relatively slow due to the long excitation time of the electromagnetic coil, generally reaching 100ms, and the response is not quick for remote control.

(3) The movable iron core of the electromagnetic stop valve acts in the magnetism isolating pipe, so that the magnetism isolating pipe is surrounded by the electromagnetic coil, and when the movable iron core is used for controlling low-temperature cryogenic (less than or equal to-100 ℃) fluid, the electromagnetic coil component can be frozen due to the long-term influence of the low temperature of the fluid. Normally, cryogenic electromagnetic stop valves are all made into long-neck valves to increase the heat exchange distance and ensure the normal work of an electromagnetic system. Because stop valve neck increases solenoid component and installs and make the stop valve focus too high topmost, this kind of structure can influence the stress balance of pipeline, especially when being applied to the operating mode that has the vibration.

(4) The continuous power supply of the electromagnetic stop valve can increase the flammable and explosive risks of the stop valve, and is not beneficial to the requirement of the energy-saving times.

(5) The design principle of an electromagnetic driving mechanism of the traditional electromagnetic stop valve enables a manual operating mechanism to enter the interior of the stop valve to directly operate a valve core so as to realize manual operation. Thus, in order to prevent the fluid from overflowing from the assembly clearance of the manual operating mechanism on the valve body, whether the sealing measures adopted by the manual operating mechanism are reliable or not becomes a key for determining the quality and the service life of the stop valve. On the basis of the principle of the existing electromagnetic stop valve, a more effective solution that a manual operating mechanism is isolated from fluid and is operated is fundamentally solved.

Generally, a manual operating mechanism of an electromagnetic stop valve with the manual operating mechanism is installed on a valve body, and the mechanism transversely penetrates through the valve body to realize manual opening and closing of the stop valve by adjusting the working position of a valve core. The connection of the part of the manual operating mechanism, which is positioned on the outer side of the valve body, and the valve body realizes the fluid leakage blocking through the sealing element, but the sealing performance and the service life of the sealing element are influenced by the factors such as the machining precision of components, the assembling quality, the material of the sealing element, the operating rationality, the fluid pressure, the environment and the like, and the sealing failure condition is often caused after long-term use.

In addition, the manual operating mechanism is positioned on one side of the valve body, so that the installation position of the stop valve is limited, and the optimal design of a pipeline is not facilitated.

How to solve the problems so that the stop valve can meet the industrial control requirements of the intelligent era becomes a matter to be solved urgently.

Disclosure of Invention

The invention aims to solve the technical problem of providing a stop valve which can maintain the working state without continuous power-on, has quick action response and simple structure.

In order to solve the technical problems, the invention adopts the following technical scheme.

A shut-off valve comprising:

a valve body;

the permanent magnet operating mechanism comprises a shell arranged in the valve body, a coil and a permanent magnet which are arranged in the shell, and a movable iron core movably sleeved in the coil and the permanent magnet;

the valve rod comprises a first end extending into the valve body and a second end extending out of the valve body and penetrating through the movable iron core;

a first force transfer structure disposed on the valve stem;

the elastic device is used for connecting the valve rod and the movable iron core, preventing the movable iron core from moving towards the second end direction and storing energy, applying acting force to the valve rod in the process of preventing the movable iron core from moving towards the second end direction so as to enable the valve rod to move towards the direction away from the valve body, and applying acting force to the movable iron core after energy is stored so as to generate the initial speed of the movable iron core moving towards the first force transmission structure direction;

wherein the movable iron core can reciprocate along the valve rod; when the movable iron core is abutted against the first force transmission structure, the movable iron core applies an acting force which pushes the valve rod to move towards the valve body direction to the first force transmission structure.

Still include manual operation mechanism and set up in the second power transmission structure of second end, this manual operation mechanism includes:

a support member mounted to the housing and including a guide hole;

the converter is arranged in the guide hole and forms a linear guide rail pair with the guide hole, the surface of the converter facing the valve body is provided with an inwards concave conversion space, the side wall of the conversion space is provided with a convex part, the second force transmission structure is positioned in a space enclosed by the convex part, the side wall and the bottom surface of the conversion space and is hooked with the convex part, and the second force transmission structure is movably matched with the enclosed space;

and a screw rod which is arranged on the support piece and can rotate in a reciprocating manner by taking the axis of the screw rod as a shaft, and the screw rod and the converter form a screw rod nut pair.

The elastic device is a pressure spring arranged between the second force transmission structure and the movable iron core.

The cross section of the guide hole is polygonal.

The housing is integrally formed with the support member.

Still include bellows assembly, this bellows assembly includes:

the outer sleeve is arranged between the valve body and the shell and comprises a through hole movably sleeved on the valve rod;

the corrugated pipe is sleeved on the valve rod, one end of the corrugated pipe is fixedly connected with the valve rod in a sealing mode, and the other end of the corrugated pipe is connected with the part of the outer sleeve surrounding the circumference of the through hole in a sealing mode.

The outer sleeve further comprises a concave cavity with an opening facing the valve body, and the corrugated pipe is arranged in the concave cavity.

The outer casing is integrally formed with the housing.

The elastic device is a tension spring with one end connected with the valve rod and the other end connected with the movable iron core.

The first force transfer structure is an axial step.

The present invention has the following advantageous technical effects.

The first end of the valve rod extends into the valve body, the second end of the valve rod extends out of the valve body and then penetrates through the movable iron core, and the movable iron core can reciprocate along the valve rod; the elastic device is used for connecting the valve rod and the movable iron core, preventing the movable iron core from moving towards the second end direction and storing energy, applying acting force to the valve rod in the process of preventing the movable iron core from moving towards the second end direction so as to enable the valve rod to move towards the direction far away from the valve body, and applying acting force to the movable iron core after energy is stored so as to generate the initial speed of the movable iron core moving towards the direction of the first force transmission structure; when the movable iron core is abutted to the first force transmission structure, the movable iron core applies an acting force for pushing the valve rod to move towards the valve body direction to the first force transmission structure. Taking a normally open type as an example, the closing and opening processes of the present invention are described as follows: when the valve needs to be closed, a pulse electric signal is introduced, the coil generates magnetic force to drive the movable iron core to move towards the second end direction of the valve rod, the movable iron core applies acting force to the elastic device, meanwhile, the elastic device blocks the movable iron core to move towards the second end direction and store energy, in the process of blocking the movable iron core to move towards the second end direction, the elastic device applies acting force to the valve rod to drive the valve rod to move towards the direction far away from the valve body, when the movable iron core moves to the first limit position, the valve is completely closed, the introduction of the pulse electric signal is stopped, and the permanent magnet enables the movable iron core to be kept at the first limit position. When needing to open, let in the pulse signal of telecommunication, the magnetic force of permanent magnet is overcome to the magnetic force that the coil produced, the aforesaid can release that elastic device stored when closing and apply the effort in moving the iron core in order to produce the initial velocity that moves the iron core and move to first power transmission structure direction, move the iron core and leave first extreme position fast, move the iron core and move to the valve body direction, then, at the elasticity of reset spring release, valve rod dead weight and move the iron core and leave behind the first extreme position under the combined action of the produced power of second extreme position magnetic attraction power attraction movable iron core promotion first power transmission structure, the valve rod moves to the valve body direction, finally open the stop valve. The elastic force released by the reset spring, the dead weight of the valve rod and the magnetic force of the second limit position attract the movable iron core to push the superposed structure of the force generated by the first force transmission structure, and the superposed structure is different from a structure which only depends on the elastic force released by the reset spring and the dead weight of the valve rod to realize the opening of the valve when the existing stop valve is opened, so that the valve is quicker in opening action response and more reliable in opening action. The permanent magnet operating mechanism has short pulse electrifying action response time (less than or equal to 50 ms), extremely small instantaneous electrifying energy consumption, reliable and durable permanent magnet, high efficiency, energy conservation and reduction of inflammable and explosive risks, and can maintain a working state without continuous electrifying. The invention can maintain the working state without continuous power-on, and has quick action response and simple structure.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

Detailed Description

In order to explain the technical features and effects of the present invention in detail and to enable the implementation thereof in accordance with the content of the present specification, the following further describes embodiments of the present invention.

The invention is described herein with reference to a normally open shut-off valve as an example. This should not be construed as limiting the scope of the invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention.

Unless specifically stated otherwise, the terms "first" and "second" herein do not denote any order or importance, nor do they denote any importance.

FIG. 1 schematically illustrates a block diagram of a shut-off valve in accordance with various embodiments of the present invention. The stop valve comprises a valve body 1, a permanent magnet operating mechanism, a valve rod 5, an elastic device 11 and a first force transmission structure 20.

A valve seat 3 is installed in the valve body 1.

The permanent magnet operating mechanism comprises a sub-magnetic ring 6, a movable iron core 12, a permanent magnet 13, a magnetic yoke 14, a coil 15 and a shell 17.

The housing 17 is mounted to the valve body 1 (when a bellows assembly described later is not included), for example, by screw coupling between the housing 17 and the valve body 1.

In this embodiment, the permanent magnet 13 and the coil 15 are sequentially arranged from top to bottom (for convenience of description, the up-down direction shown in fig. 1), and the magnetic fields generated by the permanent magnet 13 and the coil 15 are superposed and matched. After the coil 15 and the permanent magnet 13 are assembled in the magnetic yoke 14, the coil 15 and the permanent magnet 13 are installed in the shell 1, and the magnetic yoke 14 is used for restraining magnetic lines of force generated by the coil 15 and the permanent magnet 13 from being dispersed outwards, so that the magnetic lines of force are transmitted to the movable iron core 12 more intensively. The movable iron core 12 is movably sleeved in the coil 15 and the permanent magnet 13.

The first end of the valve rod 5 extends into the valve body 1 and is fixedly connected with the valve clack 2. The second end of the valve rod 5 extends out of the valve body 1 and then passes through the movable iron core 12, and the movable iron core 12 can reciprocate along the valve rod 5. For example, the valve rod 5 is movably sleeved in the movable iron core 12, so that the valve rod 5 is movably matched with the movable iron core 12, and the movable iron core 12 can reciprocate along the valve rod 5.

In order to prevent the energy loss caused by the leakage of the magnetic field, a magnetic shunt ring 6 is arranged between the end surface of the permanent magnet 13 facing the second end of the valve rod 5 and the magnetic yoke 14.

The first force transfer structure 20 is arranged at the valve stem 5. In the embodiment shown in fig. 1, the first force transmission structure 20 is a step integrally formed on the valve rod 5, and it is understood that the first force transmission structure 20 is not limited to the step, and may be other structures capable of blocking the plunger 12 and pushing the valve rod 5 to move toward the valve body 1 by the force of the plunger 12, such as a pin radially penetrating and fixed on the valve rod 5 or a ring sleeved and fixed on the valve rod 5.

In the embodiment presented in fig. 1, the second end of the valve stem 5 is provided with a second force transmission structure 5-1. The elastic device 11 is a pressure spring, and is installed between the second force transmission structure 5-1 and the movable iron core 12, specifically, the pressure spring is installed on the valve rod 5, and is installed between the movable iron core 12 and the opposite end surface of the second force transmission structure 5-1, so as to connect the valve rod 5 and the movable iron core 12.

When the stop valve is closed, the movable iron core 12 moves towards the second end of the valve rod 5, the pressure spring is compressed, and the pressure spring pushes the second force transmission structure 5-1 to drive the valve rod 5 to move towards the direction far away from the valve body 1. When the valve clack 2 reaches the closing position, the valve rod 5 finishes the closing action and stops moving towards the direction far away from the valve body 1, the movable iron core 12 still continues to move for a certain distance towards the direction of the second end of the valve rod 5, and the position state is kept by the permanent magnet 13 after the first limit position is reached and the magnetic yoke 14 is contacted. And in the closing process of the stop valve, the pressure spring is compressed and stores energy. The distance of the continuous movement of the plunger 12 is the overtravel, and the interference pressure obtained by the spring compressing the distance acts on the second force transmission structure 5-1 to provide proper closing force except the pressure of the fluid to the valve clack 2 at the closing position, thereby ensuring the closing tightness of the valve clack 2.

When the stop valve is opened, the compressed spring which is compressed and stored energy is expanded to apply acting force to the movable iron core 12, and the initial speed of the movable iron core 12 moving towards the first force transmission structure 20 is generated. The movable iron core 12 moves towards the valve body 1, and when the movable iron core 12 abuts against the first force transmission structure 20, the movable iron core 12 applies an acting force which pushes the valve rod 5 to move towards the valve body 1 to the first force transmission structure 20.

It is understood that the elastic device 11 is not limited to a compression spring, but may be other elastic members, such as a tension spring with one end connected to the valve rod 5 and the other end connected to the movable iron core 12, so as to connect the valve rod 5 and the movable iron core 12.

The valve stem 5 is preferably made in one piece with the second force transmission structure 5-1. For example, fig. 1 shows an embodiment in which the second force transmission structure 5-1 is a boss integrally formed at the second end of the valve stem 5. It will be appreciated that the second force-transmitting structure 5-1 is not limited to a boss, but may be other structures capable of blocking the resilient means 11, such as a pin radially inserted through the second end of the valve stem 5 or a ring sleeved on the second end of the valve stem 5.

It can be seen that the elastic device 11 is used to block the plunger 12 from moving towards the second end of the valve rod 5 and store energy, and apply an acting force to the valve rod 5 during the process of blocking the plunger 12 from moving towards the second end of the valve rod 5 so as to move the valve rod 5 away from the valve body 1. The elastic device 11 is also used for applying a force to the plunger 12 after energy storage to generate an initial speed of the plunger 12 moving towards the first force transmission structure 20.

In an electromagnetic operation mode, the opening and closing state of the stop valve is not required to be maintained by electrifying a coil, the permanent magnet 13 reliably maintains the movable iron core 12 at the first and second limit positions by utilizing a low magnetic impedance channel established by the movable iron core 12 and the magnetic yoke 14 (when the movable iron core 12 is located at the first limit position, the stop valve in the embodiment is completely closed, and when the movable iron core 12 is located at the second limit position, the stop valve in the embodiment is completely opened), and the valve rod 5 linked with the movable iron core 12 drives the valve clack 2 to realize the opening and closing of the stop valve and maintain the state of the stop valve. When the stop valve is switched between the open state and the closed state, the coil 15 is energized with instantaneous pulse current to generate magnetic force in a direction opposite to the direction of the magnetic force at the holding position of the permanent magnet 13, the magnetic force overcomes the holding force of one end of the permanent magnet 13 on the movable iron core 12 at the position, such as a first limit position, on the one hand, and also generates attraction force for urging the movable iron core 12 to move to another position, such as a second limit position, on the other hand, the resultant force of the magnetic field generated by the coil 15 and the magnetic field at the other end of the permanent magnet 13 urges the movable iron core 12 to move to another position and the other end of the permanent magnet 13 continues to hold the state, and the stop valve completes the switching between the open state and the closed state.

In the above embodiments, the arrangement of the return spring is well known and will not be described again.

In some embodiments, the present invention also includes a bellows assembly that includes a bellows 4 and a jacket 16.

The outer sleeve 16 is installed between the valve body 1 and the housing 17, for example, the outer sleeve 16 is connected to the valve body 1 and the housing 17 by screw threads. The outer casing 16 is preferably made in one piece with the housing 17. Obviously, the jacket 16 can also be made integral with the valve body 1.

The outer sleeve 16 comprises a through hole movably sleeved on the valve rod 5 and a concave cavity opening towards the valve body 1.

The corrugated pipe 4 is sleeved on the valve rod 5, and is arranged in the concave cavity.

One end of the bellows 4 is fixedly connected with the valve rod 5 in a sealing manner, for example, the end of the bellows 4 is fixedly connected with the valve rod 5 in a sealing manner, an axial step 5-2 is arranged at a position of the valve rod 5 close to the first end, and the end of the bellows 4 is connected with an end face of the axial step 5-2 facing the housing 17 in a welding and sealing manner. The other end of the bellows 4 is sealingly connected to a portion of the outer sleeve 16 surrounding the circumference of the through-hole of the valve stem 5, for example, by welding. When the valve rod 5 is opened or closed, the bellows 4 is compressed or extended, the bellows 4 becomes a motion actuator which can isolate fluid and bear the pressure of the fluid, and can link the valve rod 5 to drive the valve clack 2 to complete the opening or closing action, for example, when the valve rod is opened, the bellows 4 can provide reset elastic force applied to the valve rod 5.

In view of the above, when the bellows 4 is provided, the return spring in the related art can be eliminated.

In some embodiments, a manual operating mechanism is also included, which includes support 18, converter 10, and screw 9.

The support 18 is mounted to the housing 17, which includes the guide hole 7. In the present embodiment, the guide hole 7 is an inner hexagonal hole. Obviously, the guide hole 7 is not limited to the inner hexagonal hole, but may be other holes, for example, an inner pentagonal hole, as long as the hole can restrict the circumferential rotation of the converter 10, for example, a hole having a polygonal cross section.

The converter 10 is disposed in the guide hole 7, and forms a linear guide pair with the guide hole 7. The surface of the converter 10 facing the valve body 1 is provided with an inwards concave conversion space 10-1, the side wall of the conversion space 10-1 is provided with a convex part 10-2, a second force transmission structure 5-1 of the valve rod 5 is positioned in a space enclosed by the convex part 10-2 and the side wall and the bottom surface of the conversion space 10-1, the second force transmission structure 5-1 is hooked with the convex part 10-2, and the second force transmission structure 5-1 is movably matched with the enclosed space.

The screw 9 is provided on the support 18 and is capable of reciprocating rotation about its own axis, and forms a screw-nut pair with the converter 10.

In this embodiment, the supporting element 18 is a cover covering the housing 17 to cover the opening of the housing 17. Obviously, the support member 18 is not limited to the case cover, and may be any structure capable of supporting the screw 9. It will be appreciated that the housing 17 is preferably made integral with the support 18.

In the manual operation, the screw 9 and the converter 10 form a screw nut pair, and the converter 10 and the guide hole 7 form a linear guide rail pair, so that the reciprocating rotational motion of the screw 9 is converted into the reciprocating linear motion of the converter 10 along the axial direction of the guide hole 7. The surface of the converter 10 facing the valve body 1 is provided with an inwards concave conversion space 10-1, the side wall of the conversion space 10-1 is provided with a convex part 10-2, the second force transmission structure 5-1 is positioned in a space enclosed by the convex part 10-2 and the side wall and the bottom surface of the conversion space 10-1, the second force transmission structure 5-1 is hooked with the convex part 10-2, and the second force transmission structure 5-1 is movably matched with the enclosed space. The screw rod 9 is rotated, the converter 10 makes linear motion under the guidance of the guide hole 7, when the converter 10 moves to the bottom surface of the conversion space 10-1 towards the valve body 1 and pushes the second end face of the valve rod 5, the valve rod 5 moves towards the valve body 1 to drive the valve clack 2 to open the stop valve, when the converter 10 moves to the bulge 10-2 far away from the valve body 1 to hook the second force transmission structure 5-1, the converter 10 drives the valve rod 5 to move towards the direction far away from the valve body 1, and further drives the valve clack 2 to close the stop valve, so that the stop valve is opened and closed manually.

When the manual operation mode needs to be converted into the electromagnetic operation mode, the screw 9 is rotated, and the converter 10 can move to the middle position 19 of the opening and closing stroke of the valve rod 5. After the converter 10 reaches the middle position 19, at this time, the reserved opening and closing stroke of the valve rod 5 is preferably equal to the movement stroke of the movable iron core 12, and the reserved opening and closing stroke of the valve rod 5 is the distance between the bottom surface of the conversion space 10-1 and the protruding part 10-2, so that the opening and closing action of the valve rod 5 in the electromagnetic operation mode is not influenced by the limitation of the converter 10, and the reasonable conversion between the manual operation mode and the electromagnetic operation mode is realized.

To facilitate manual operation, the manual operating mechanism further comprises a hand wheel 8 fixedly connected to the end of the screw 9 opposite to the converter 10.

The invention has compact design structure, low gravity center, permanent magnet maintenance, convenient installation, sensitive and reliable permanent magnet operating mechanism, no heat source generated by permanent magnet maintenance, energy conservation, safe and simple manual operation, and realizes the technical performance requirements of reliability, safety, operability, energy conservation and reduction of the influence of the temperature of the stop valve on fluid.

It should be noted that the various features described in the foregoing embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in any further detail in order to avoid unnecessary repetition.

The present invention has been described in detail with reference to the embodiments, which are illustrative rather than restrictive, and variations and modifications thereof are possible within the scope of the present invention without departing from the general inventive concept.

Claims

1. A shut-off valve, comprising:

a valve body;

the permanent magnet operating mechanism comprises a shell arranged in the valve body, a magnet yoke arranged in the shell, a coil and a permanent magnet arranged in the magnet yoke, and a movable iron core movably sleeved in the coil and the permanent magnet;

a first force transfer structure disposed on the valve stem;

the second force transmission structure is arranged at the second end of the valve rod;

the elastic device is arranged between the second force transmission structure and the movable iron core, connects the valve rod and the movable iron core, is used for preventing the movable iron core from moving towards the second end direction and storing energy, applies acting force to the valve rod in the process of preventing the movable iron core from moving towards the second end direction so as to enable the valve rod to move towards the direction far away from the valve body, and applies acting force to the movable iron core after storing energy so as to generate the initial speed of the movable iron core moving towards the first force transmission structure direction;

wherein the movable iron core can reciprocate along the valve rod; when the movable iron core abuts against the first force transmission structure, the movable iron core applies an acting force for pushing the valve rod to move towards the valve body direction to the first force transmission structure;

when the valve clack reaches the closing position, the movable iron core still can continuously move a certain distance towards the second end direction of the valve rod, the position state of the movable iron core is kept by the permanent magnet after the movable iron core reaches the first limit position and is contacted with the magnetic yoke, the distance of the continuous movement of the movable iron core is the overtravel, the interference pressure obtained by the elastic device for compressing the distance acts on the second force transmission structure, and closing force except the pressure of fluid is provided for the valve clack at the closing position.

2. The shut-off valve of claim 1, further comprising a manually operated mechanism comprising:

a support member mounted to the housing and including a guide hole;

3. The shut-off valve of claim 2, wherein the resilient means is a compression spring disposed between the second force transfer structure and the plunger.

4. The shut-off valve of claim 2, wherein the guide hole is polygonal in cross-section.

5. The shut-off valve of claim 2, wherein the housing is integrally formed with the support.

6. The shut-off valve of claim 1, further comprising a bellows assembly comprising:

the corrugated pipe is sleeved on the valve rod, one end of the corrugated pipe is fixedly connected with the valve rod in a sealing mode, and the other end of the corrugated pipe is connected with the part, surrounding the circumferential direction of the through hole, of the outer sleeve in a sealing mode.

7. The shut-off valve of claim 6, wherein the outer sleeve further comprises a cavity opening toward the valve body, the bellows being disposed within the cavity.

8. The shut-off valve of claim 6, wherein the outer sleeve is integrally formed with the housing.

9. The shut-off valve of any one of claims 1, 2, 4-8, wherein the resilient means is a tension spring having one end connected to the valve stem and the other end connected to the plunger.

10. A shut-off valve as claimed in any one of claims 1-8, wherein the first force transfer arrangement is an axial step.