Pressure control valve

Abstract

One or more embodiments of the present specification relate to a pressure control valve comprising: a valve body comprising a cavity, and first and second fluid communication ports communicating the cavity with the outside of the valve body; the valve element is movably arranged in the cavity, and the valve element moves to enable the first fluid communication opening and the second fluid communication opening to be connected or disconnected; and the pressure compensation structure is arranged between the valve element and the valve body, and when the fluid pressure around the pressure compensation structure is lower than a critical value, the pressure compensation structure provides acting force for preventing the pressure control valve from being opened for the valve element.

Description

Technical Field

[0001] The present specification relates to the technical field of pressure valves, and in particular to a pressure control valve. Background Art

[0002] Superconducting magnets generally use liquid helium as a cooling medium. A large amount of liquid helium is injected into the inner cavity of the superconducting magnet to soak the superconducting coils, so that the superconducting coils remain in a superconducting state. On the path where the inner container of the superconducting magnet is connected to the external environment, one or more pressure control valves are arranged to control the connection or isolation between the inner container of the superconducting magnet and the outside of the superconducting magnet.

[0003] The current pressure control valve generally includes a relative pressure control mode and an absolute pressure control mode. The relative pressure control means that the valve of the pressure control valve uses a variable pressure, such as atmospheric pressure, as a reference to control the difference between the internal pressure of the superconducting magnet and the external pressure of the superconducting magnet to a fixed value. The absolute pressure control mode uses an immutable pressure (such as vacuum) as a reference, and the opening of its valve is only related to the internal pressure of the superconducting magnet. Generally speaking, the pressure control valve using the relative pressure control method has a simpler structure, lower cost, and is more convenient to use. However, in practical applications, such as during the transportation of superconducting magnets, its refrigeration equipment is usually in a shutdown state. The heat transmitted from the outside to the inner container of the superconducting magnet will cause the liquid helium to volatilize and the pressure to rise. At this time, the superconducting magnet must be exhausted and depressurized to the external environment through the above-mentioned pressure control valve. If the external environment pressure is significantly reduced during transportation, the opening pressure of the valve of the pressure control valve using the relative pressure control method will be significantly reduced, which means that more helium will be released, resulting in unnecessary liquid helium loss. At the same time, the too low helium pressure in the superconducting magnet may affect the refrigeration efficiency of the refrigerator. For the pressure control valve using absolute pressure control, the set pressure of the valve is only related to the internal pressure of the superconducting magnet and is not affected by the change of external environmental pressure. However, the pressure control valve using absolute pressure control has a more complex structure and higher cost. At the same time, this type of pressure control valve needs to add special elastic parts, which have low reliability, resulting in low working stability of the pressure control valve.

[0004] Based on the above reasons, this specification provides a pressure control valve that can realize automatic switching between relative pressure control and absolute pressure control, effectively improve the stability of the pressure control valve during operation, improve the applicability of the pressure control valve, and flexibly control the internal pressure of the superconducting magnet. Summary of the invention

[0005] One of the embodiments of the present specification provides a pressure control valve, comprising: a valve body, comprising a cavity and a first fluid connecting port and a second fluid connecting port connecting the cavity to the outside of the valve body; a valve core, movably arranged in the cavity, the valve core moves to connect or disconnect the first fluid connecting port and the second fluid connecting port; a pressure compensation structure, arranged between the valve core and the valve body, when the fluid pressure around the pressure compensation structure is lower than a critical value, the pressure compensation structure provides a force to the valve core to hinder the opening of the pressure control valve.

[0006] In some embodiments, the pressure compensation structure includes a first elastic member, the first elastic member includes a sealed cavity, the internal air pressure of the sealed cavity is a preset pressure, and the expansion and contraction direction of the first elastic member is parallel to the movable direction of the valve core.

[0007] In some embodiments, the cavity includes a first partition chamber and a second partition chamber, the first partition chamber is connected to the first fluid connecting port, and the second partition chamber is connected to the second fluid connecting port; the valve core moves to connect or disconnect the first partition chamber and the second partition chamber; the first elastic member is arranged in the first partition chamber, and is located between the valve core and the valve body along the movable direction of the valve core.

[0008] In some embodiments, when the internal fluid pressure of the first elastic member is the same as the external fluid pressure, the length of the first elastic member along the extension and contraction direction is an initial length; when the internal fluid pressure of the first elastic member and the external fluid pressure have a first pressure difference, the length of the first elastic member along its own extension and contraction direction is a first length; when the valve core separates the first separation chamber and the second separation chamber, the distance between the valve core and the valve body along the movable direction of the valve core is a second length, the initial length of the first elastic member is greater than the second length, and the second length is greater than the first length.

[0009] In some embodiments, the valve core includes a first valve core, the first valve core is located in the first separation chamber, and along a movable direction perpendicular to the valve core, a cross-sectional area of ​​the first valve core is greater than a cross-sectional area of ​​the second separation chamber.

[0010] In some embodiments, the valve core includes a first valve core and a second valve core connected to the first valve core, the first valve core is located in the first separation chamber, the second valve core is at least partially located in the second separation chamber, and at the connection between the first valve core and the second valve core, along a movable direction perpendicular to the valve core, the cross-sectional area of ​​the first valve core is greater than the cross-sectional area of ​​the second valve core, and the cross-sectional area of ​​the first valve core is greater than the cross-sectional area of ​​the second separation chamber.

[0011] In some embodiments, a sealing member is further included, which is arranged between the valve body and the valve core; the pressure-bearing area of ​​the first elastic member in the telescopic direction is a first area, and the sealing cross-sectional area of ​​the sealing member in the telescopic direction of the first elastic member is a second area, and the absolute value of the difference between the first area and the second area is less than a preset value.

[0012] In some embodiments, one end of the first elastic member along the telescopic direction is connected to the valve core, and the other end is a free end; and / or one end of the first elastic member along the telescopic direction is connected to the valve body, and the other end is a free end.

[0013] In some embodiments, a second elastic member is further included, one end of the second elastic member is connected to the valve core, and the other end is directly or indirectly connected to the valve body; the second elastic member has a preset preload force.

[0014] In some embodiments, a preload force applying device is also included, which includes a tensioning member and a locking member. The tensioning member is connected to the other end of the second elastic member and is movably connected to the valve body through the locking member. Movement of the tensioning member changes the preload force of the second elastic member.

[0015] The pressure control valve provided by the present invention can be applied to some containers in the chemical and mechanical fields that are sensitive to the fluid pressure changes of the external environment, and is used to connect or isolate the interior of the container from the outside world, so that these containers can adapt to the changes in the external fluid pressure, and flexibly control the internal pressure of the container. When the pressure control valve is applied to the pipeline connecting the superconducting magnet and the external environment, for the superconducting magnet installed in a non-plateau or non-atmospheric pressure sudden change environment, since the fluid pressure around the pressure compensation structure is not lower than the critical value, the pressure compensation structure is in a "closed" state, does not participate in the opening and closing of the pressure control valve, and the pressure control valve works in a relative pressure control mode, and the pressure compensation structure will not be affected by the valve core or valve body, which can effectively extend the service life of the pressure compensation structure. When the superconducting magnet undergoes a process of external pressure changes such as air transportation, the fluid pressure around the pressure compensation structure is lower than the critical value, so the pressure compensation structure is in an "open" state, and the pressure compensation structure can apply a force to the valve core that hinders the valve from opening, so that the opening pressure of the valve of the pressure control valve is only related to the internal pressure of the magnet, and is not affected by the change of the external environment air pressure, and the pressure control valve works in an absolute pressure control mode. After the external environment pressure is restored, the pressure control valve can switch to the relative pressure control mode. Since the pressure control valve can switch between the relative pressure control mode and the absolute pressure control mode according to the changes in the air pressure of the external environment, the internal pressure of the superconducting magnet can be flexibly controlled without being affected by the changes in the air pressure of the external environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] This specification will be further described in the form of exemplary embodiments, which will be described in detail by the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

[0017] Figure 1 is a cross-sectional schematic diagram of a pressure control valve in a relative pressure control mode according to some embodiments of the present specification;

[0018] Figure 2 is a cross-sectional schematic diagram of a pressure control valve in an absolute pressure control mode according to some embodiments of the present specification;

[0019] Figure 3 is a cross-sectional schematic diagram of a pressure control valve in a relative pressure control mode according to other embodiments of the present specification;

[0020] Figure 4 is a cross-sectional schematic diagram of a pressure control valve in an absolute pressure control mode according to other embodiments of the present specification;

[0021] Figure 5 It is a cross-sectional schematic diagram of a pressure control valve shown in some other embodiments of the present specification. DETAILED DESCRIPTION

[0022] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of this specification. For ordinary technicians in this field, this specification can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0023] As shown in this specification and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "comprise" and "include" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0024] One or more pressure control valves are arranged on the path connecting the inner container of the superconducting magnet with the external environment. When the superconducting magnet is in normal working state, under the action of the refrigeration equipment, the liquid helium will undergo the process of volatilization into gas due to heat and then condensation into liquid. The internal air pressure of the inner container of the superconducting magnet is maintained at a low state. At this time, the pressure control valve is in a closed state, so the helium will not escape outside the superconducting magnet, and the superconducting magnet maintains zero volatilization of liquid helium. When the internal air pressure of the inner container of the superconducting magnet increases, the helium in the superconducting magnet needs to be released in time through the pressure control valve on the pipeline connecting the inside and outside of the superconducting magnet, otherwise the superconducting magnet will be damaged or even cause serious safety accidents. For example, when the superconducting magnet is under long-term strong gradient working conditions, the eddy current heating effect generates more heat inside the superconducting magnet, and the liquid helium will be heated and vaporized, causing the internal pressure of the superconducting magnet to gradually rise. For example, when a superconducting magnet quenches its superconducting properties (i.e., any of the temperature, magnetic field, and current of the superconducting magnet exceeds a critical value, and the superconducting magnet transforms into a normal conductive magnet), the inductive energy storage of the superconducting coil will be released instantaneously, the liquid helium will be heated and quickly vaporized into hundreds of times the volume of helium, and the pressure inside the superconducting magnet will increase rapidly.

[0025] The current pressure control valves usually include relative pressure control mode and absolute pressure control mode. Relative pressure control means that the valve of the pressure control valve uses variable pressure, such as atmospheric pressure, as a reference to control the difference between the internal pressure of the superconducting magnet and the ambient pressure as a fixed value. The absolute pressure control mode uses an immutable pressure (such as vacuum) as a reference, and the opening of the valve is only related to the internal pressure of the container.

[0026] In practical applications, for example, during the transportation of superconducting magnets, their refrigeration equipment is usually in a shutdown state. The heat leakage from the external environment to the inside of the container will cause the liquid helium to volatilize and the pressure to rise. At this time, the superconducting magnet must be vented to the external environment through the pressure control valve to release the pressure. If the external environmental pressure is significantly reduced during transportation, such as from Shanghai to Tibet and other high-altitude areas, the external atmospheric pressure is only 2 / 3 of the air pressure in the plain area. At this time, if the pressure control valve adopts a relative pressure control method, the opening pressure of the valve will be significantly reduced, and the discharge pressure of the superconducting magnet will also be greatly reduced. More helium will be released, causing unnecessary liquid helium loss. At the same time, the excessively low helium pressure in the superconducting magnet may affect the refrigeration efficiency of the refrigeration equipment. For another example, during the take-off and landing of a cargo plane transporting superconducting magnets, there may also be a sudden change in pressure in the cabin. If a relative pressure control method is adopted, excessive helium discharge from the superconducting magnet may also occur when the pressure is lost at high altitude, thereby endangering the flight safety of the aircraft. If the pressure control valve adopts absolute pressure control, the opening pressure of the valve is only related to the internal pressure of the magnet, and is not affected by the change of external environmental air pressure. However, the pressure control valve adopting absolute pressure control is more complex in structure and more expensive. At the same time, this type of pressure control valve needs to add additional special elastic parts. Due to the low reliability of the special elastic parts, the working stability of the pressure control valve is low and the service life is short.

[0027] The pressure control valve provided in the embodiment of this specification can be applied to certain containers in the chemical and mechanical fields that are sensitive to changes in fluid pressure in the external environment, and is used to connect or isolate the interior of the container from the outside world. Through the pressure control valve of this specification, these containers can adapt to changes in external fluid pressure and flexibly control the internal pressure of the container. The pressure control valve provided in the embodiment of this specification can be applied to various pipeline systems, especially pipeline control areas that are sensitive to pressure changes in the pipeline. As a specific example, the pressure control valve provided in the embodiment of this specification can be applied to a pipeline connecting a superconducting magnet with the external environment, and is used to connect or isolate the inner container of the superconducting magnet from the external environment. The pressure control valve includes a valve body, a valve core arranged in the cavity of the valve body, and a pressure compensation structure arranged between the valve body and the valve core, and the pressure compensation structure can change the pressure difference required to open the pressure control valve. Taking the inner container of the superconducting magnet as an example, the cavity of the valve body connects the inner container cavity of the superconducting magnet with the external environment (for example, the atmospheric environment) of the pressure control valve through the first fluid communication port and the second fluid communication port respectively. When the fluid pressure around the pressure compensation structure is not lower than the critical value, the pressure compensation structure will not affect the pressure difference of opening the valve. The valve of the pressure control valve is opened with a fixed fluid pressure difference, that is, when the pressure control valve is opened, the difference between the internal pressure of the superconducting magnet and the fluid pressure of the external environment is a fixed value, and the pressure control valve at this time is in a relative pressure control mode. When the fluid pressure around the pressure compensation structure is lower than the critical value (for example, the fluid pressure around the pressure compensation structure is a plateau environment or an environment where the atmospheric pressure is significantly reduced), the pressure compensation structure can provide a force to the valve core that hinders the opening of the pressure control valve, so that the fluid pressure difference required to open the pressure control valve changes (such as the required fluid pressure difference increases). In some embodiments, by designing the parameters of the pressure compensation structure, the change in the fluid pressure difference required to open the pressure control valve can be made equivalent to the change in the fluid pressure of the external environment of the pressure control valve, so that the opening pressure of the valve of the pressure control valve is only related to the internal pressure of the magnet, and is not affected by the change in the air pressure of the external environment, that is, the pressure control valve at this time is in an absolute pressure control mode.

[0028] In some cases, when the pressure control valve is used in the pipeline connecting the superconducting magnet and the external environment, for superconducting magnets installed in non-plateau or non-atmospheric pressure sudden change environments, since the fluid pressure around the pressure compensation structure is not lower than the critical value, the pressure compensation structure is in a "closed" state and does not participate in the opening and closing of the pressure control valve. The pressure control valve works in a relative pressure control mode, and the pressure compensation structure will not be affected by the valve core or valve body, which can effectively extend the service life of the pressure compensation structure. When the superconducting magnet undergoes a process of external pressure change such as air transportation, the fluid pressure around the pressure compensation structure is lower than the critical value, so the pressure compensation structure is in an "open" state, and the pressure compensation structure can apply a force to the valve core that hinders the opening of the valve, so that the opening pressure of the valve of the pressure control valve is only related to the internal pressure of the magnet, and is not affected by the change of the external environmental air pressure. The pressure control valve works in an absolute pressure control mode. After the external environmental pressure is restored, the pressure control valve can switch to the relative pressure control mode again. Since the pressure control valve can switch between the relative pressure control mode and the absolute pressure control mode according to the changes in the air pressure of the external environment, the internal pressure of the superconducting magnet can be flexibly controlled without being affected by the changes in the air pressure of the external environment.

[0029] In some embodiments, Figure 1 and Figure 2 As shown, the pressure control valve 10 may include a valve body 11, a valve core 12 and a pressure compensation structure 13. The valve body 11 may include a cavity 111 and a first fluid communication port 114 and a second fluid communication port 115 that connect the cavity 111 with the outside of the valve body 11. The valve core 12 is movably disposed in the cavity 111. The movement of the valve core 12 may connect or disconnect the first fluid communication port 114 and the second fluid communication port 115, and accordingly, the pressure control valve 10 is opened or closed. The pressure compensation structure 13 is disposed between the valve core 12 and the valve body 11. When the fluid pressure around the pressure compensation structure 13 is lower than a critical value, the pressure compensation structure 13 provides a force to the valve core 12 that hinders the opening of the pressure control valve 10.

[0030] Among them, the first fluid communication port 114 and the second fluid communication port 115 are respectively used for supplying fluid from the outside of the valve body 11 to the inside of the valve body 11, or for supplying fluid from the inside of the valve body 11 to the outside of the valve body 11. In some embodiments, the fluid may include gas or liquid. For example, when the pressure control valve 10 is applied to a pipeline connecting the outside and inside of a superconducting magnet, the fluid may be helium. In some embodiments, the outside of the valve body 11 may include a first pressure environment and a second pressure environment, and the two ends of the first fluid communication port 114 are respectively connected to the cavity 111 and the first pressure environment, and the two ends of the second fluid communication port 115 are respectively connected to the cavity 111 and the second pressure environment. Just as an example, when the pressure control valve 10 is applied to a pipeline connecting the inner container cavity of a superconducting magnet with the atmospheric environment, the outside of the valve body 11 may include the inner container cavity of the superconducting magnet and the external environment of the superconducting magnet (for example, the atmospheric environment). The two ends of the first fluid communication port 114 are respectively connected to the cavity 111 and the atmospheric environment, and the two ends of the second fluid communication port 115 are respectively connected to the cavity 111 and the inner container cavity of the superconducting magnet. For the sake of ease of description, the fluid that the pressure control valve 10 conducts or blocks in this specification takes gas as an example, and the fluid pressure can be expressed as gas pressure, but it should be understood that the pressure control valve of the embodiment of this specification is also applicable when applied to the conduction and isolation of liquids, and all are within the scope of protection of this application. Further, taking the application of the pressure control valve 10 to the inner container of a superconducting magnet as an example, the first pressure environment refers to the atmospheric environment, and the second pressure environment refers to the inner container cavity of the superconducting magnet. When the valve core 12 moves so that the first fluid connection port 114 is connected to the second fluid connection port 115, the pressure control valve 10 is in an open state, and the inner container cavity of the superconducting magnet is connected to the atmospheric environment. At this time, the helium in the inner container cavity of the superconducting magnet can be released into the atmospheric environment through the passage of the pressure control valve 10, thereby achieving the purpose of pressure relief. When the valve core 12 moves to isolate the first fluid communication port 114 from the second fluid communication port 115, the pressure control valve 10 is in a closed state, and the inner container cavity of the superconducting magnet is isolated from the atmospheric environment. At this time, the inner container cavity of the superconducting magnet can be regarded as a closed environment, and the helium in the inner container cavity of the superconducting magnet cannot escape. It should be noted that when the pressure control valve 10 is applied to other containers, the first pressure environment can refer to various fluid environments outside the container, and the second pressure environment can refer to the fluid environment inside the container.

[0031] like Figure 1 and Figure 2In the pressure control valve 10 shown, the valve core 12 is movably arranged in the cavity 111. The opening and closing of the pressure control valve 10 can be achieved by controlling the movement of the valve core 12 in the cavity 111. Since the cavity 111 is connected to the atmospheric environment (i.e., the first pressure environment) and the gas environment in the inner container cavity of the superconducting magnet (i.e., the second pressure environment) through the first fluid connecting port 114 and the second fluid connecting port 115, respectively. Therefore, the valve core 12 is subjected to the atmospheric pressure and the internal pressure of the inner container of the superconducting magnet (i.e., the gas pressure in the inner container cavity of the superconducting magnet). Among them, the atmospheric pressure will hinder the pressure control valve 10 from opening, and the internal pressure of the superconducting magnet will drive the pressure control valve 10 to open. When the fluid pressure around the pressure compensation structure 13 is not lower than the critical value, the pressure compensation structure 13 does not provide the valve core 12 with a force that hinders the opening of the pressure control valve 10. At this time, the opening and closing of the pressure control valve 10 is only determined by the pressure difference between the atmospheric pressure and the internal pressure of the superconducting magnet. Therefore, when the fluid pressure around the pressure compensation structure 13 is not lower than the critical value, the pressure control valve 10 is in relative pressure control mode.

[0032] In some embodiments, the fluid pressure around the pressure compensation structure 13 may be the same as the fluid pressure in the first pressure environment connected to the first fluid communication port 114. For example, the fluid pressure around the pressure compensation structure 13 may be equal to the atmospheric pressure. In some embodiments, when the fluid pressure around the pressure compensation structure 13 is not lower than the critical value, it may indicate that the atmospheric pressure is relatively stable or close to the standard atmospheric pressure, for example, the first pressure environment is a plain or an environment with a non-atmospheric pressure mutation. In some embodiments, when the fluid pressure around the pressure compensation structure 13 is lower than the critical value, it may indicate that the atmospheric pressure is low or the atmospheric pressure decreases by a large margin, for example, the first pressure environment is a plateau or an environment with a sudden change in atmospheric pressure. The sudden change in pressure in this specification refers to a pressure decrease greater than a preset value, for example, a pressure decrease greater than 30%, 40%, 60%, etc. When the fluid pressure around the pressure compensation structure 13 is lower than the critical value, the pressure compensation structure 13 will provide a force to the valve core 12 that hinders the opening of the pressure control valve 10. At this time, the valve core 12 is subjected to the combined force of the atmospheric pressure, the internal pressure of the superconducting magnet and the force of the pressure compensation structure 13, so that the pressure control valve 10 will not be opened due to changes in the external atmospheric pressure. In some embodiments, the pressure compensation structure 13 is a deformable (e.g., elastically deformable) structure. In some embodiments, when the fluid pressure in the environment surrounding the pressure compensation structure 13 changes, if the space in which the pressure compensation structure 13 is located is not restricted, the deformation amount of the pressure compensation structure 13 will change accordingly. In some embodiments, when the fluid pressure in the environment surrounding the pressure compensation structure 13 changes, if the space in which the pressure compensation structure 13 is located restricts it from continuing to produce a larger deformation amount, the force that causes the pressure compensation structure 13 to have a deformation tendency will change accordingly. In some embodiments, the critical value may refer to the fluid pressure value outside the pressure compensation structure 13 when the deformation amount of the pressure compensation structure 13 increases to the limit of the valve core 12 and the valve body 11. In some embodiments, the critical value may also refer to the fluid pressure value outside the pressure compensation structure 13 when the force that causes the pressure compensation structure 13 to have a deformation tendency can act on the valve core 12 and the valve body 11 at the same time. In some embodiments, by further disposing the pressure compensation structure 13 in a movable direction along the valve core 12 (such as Figure 1When the fluid pressure around the pressure compensation structure 13 is lower than the critical value, the two ends of the first elastic member 131 of the pressure compensation structure 13 in the expansion and contraction direction will contact the valve body 11 and the valve core 12 at the same time, thereby applying a force to the valve core 12 that hinders the opening of the pressure control valve 10. In some embodiments, the critical value can be determined based on the expected difference between the internal pressure of the superconducting magnet and the fluid pressure around the pressure compensation structure 13 when the pressure control valve 10 is opened, and the rated internal pressure of the superconducting magnet (i.e., the maximum internal pressure of the superconducting magnet). After determining the critical value, by setting the structural parameters of the pressure compensation structure 13, the pressure compensation structure 13 can apply a force to the valve core 12 that hinders the opening of the pressure control valve 10 when the ambient pressure around it is lower than the critical value. For more details on how the pressure control valve 10 applies a force to the valve core 12 that hinders the opening of the pressure control valve 10 at the critical value, and the critical value, please refer to the description of other embodiments of this specification.

[0033] In some embodiments, by further setting the relationship between the pressure-bearing area of ​​the pressure compensation structure 13 and the sealing cross-sectional area of ​​the valve core 12, the opening and closing of the pressure control valve 10 can be basically not affected by the atmospheric pressure, but mainly depends on the internal pressure of the superconducting magnet. At this time, the pressure control valve 10 is in an absolute pressure control mode. For more details about the relationship between the pressure-bearing area of ​​the pressure compensation structure 13 and the sealing cross-sectional area of ​​the valve core 12, the movement state of the valve core 12, and the combined force of the atmospheric pressure, the internal pressure of the superconducting magnet and the pressure compensation structure 13 on the pressure control valve 10, please refer to the description of other embodiments of this specification.

[0034] In some cases, by setting a pressure compensation structure 13, the pressure control valve 10 can operate in a relative pressure control mode when the first pressure environment is a plain environment (with higher atmospheric pressure) or a non-atmospheric mutation environment, so that the pressure control valve 10 can switch between the relative pressure control mode and the absolute pressure control mode when the first pressure environment is a plateau environment (with lower atmospheric pressure) or an atmospheric mutation environment, thereby enabling the pressure control valve 10 to flexibly control the internal pressure of the superconducting magnet and be basically unaffected by changes in external environmental pressure.

[0035] In some embodiments, the number of the first fluid communication port 114 and the second fluid communication port 115 may be the same or different. In some embodiments, the number of the first fluid communication port 114 and the second fluid communication port 115 may be one or more, respectively.

[0036] In some embodiments, the cavity 111 may include a first partition cavity 112 and a second partition cavity 113. The first partition cavity 112 communicates with the first fluid communication port 114, and the second partition cavity 113 communicates with the second fluid communication port 115. The movement of the valve core 12 may connect or disconnect the first partition cavity 112 and the second partition cavity 113.

[0037] In some embodiments, the valve core 12 may include a first valve core 121, which is located in the first partition chamber 112, and along a movable direction perpendicular to the valve core 12, a cross-sectional area of ​​the first valve core 121 is greater than a cross-sectional area of ​​the second partition chamber 113. Figure 1 Since the cross-sectional area of ​​the first valve core 121 is larger than the cross-sectional area of ​​the second partition chamber 113, the first valve core 121 can be limited to move only in the first partition chamber 112. Figure 1 As shown, along the movable direction of the valve core 12, the first partition chamber 112 is located above the second partition chamber, and when the first valve core 121 abuts against the bottom of the first partition chamber 112, the first valve core 121 can separate the first partition chamber 112 from the second partition chamber 113, and the pressure control valve 10 is closed. When the first valve core 121 is separated from the bottom of the first partition chamber 112, the first partition chamber 112 and the second partition chamber 113 are connected, and the pressure control valve 10 is opened.

[0038] In some embodiments, Figure 1 As shown, the valve core 12 may include a first valve core 121 and a second valve core 122 connected to the first valve core 121, the first valve core 121 is located in the first separation chamber 112, and the second valve core 122 is at least partially located in the second separation chamber 113. At the connection between the first valve core 121 and the second valve core 122, along the movable direction perpendicular to the valve core 12, the cross-sectional area of ​​the first valve core 121 is greater than the cross-sectional area of ​​the second valve core 122, and the cross-sectional area of ​​the first valve core 121 is greater than the cross-sectional area of ​​the second separation chamber 113. Since the cross-sectional area of ​​the first valve core 121 is greater than the cross-sectional area of ​​the second separation chamber 113, the first valve core 121 can be limited to move only in the first separation chamber 112, while the second valve core 122 can move in both the first separation chamber 112 and the second separation chamber 113. Similarly, when the first valve core 121 abuts against the bottom of the first partition chamber 112, the first valve core 121 can separate the first partition chamber 112 from the second partition chamber 113, and the pressure control valve 10 is closed. When the first valve core 121 separates from the bottom of the first partition chamber 112, the first partition chamber 112 and the second partition chamber 113 are connected, and the pressure control valve 10 is opened.

[0039] In some embodiments, the shape of the first valve core 121 may include a regular or other irregular shape such as a cylinder, a cuboid, a cube. In some embodiments, the shapes of the first valve core 121 and the second valve core 122 may be the same or different. In some embodiments, the first partition chamber 112 may be similar in shape to the first valve core 121, but the cross-sectional area of ​​the first partition chamber 112 is slightly larger than the cross-sectional area of ​​the first valve core 121, so that the first valve core 121 can move in the first partition chamber 112. In some embodiments, the second partition chamber 113 may be similar in shape to the second valve core 122, but the cross-sectional area of ​​the second partition chamber 113 is slightly larger than the cross-sectional area of ​​the second valve core 122, so that the second valve core 122 can move in the second partition chamber 113.

[0040] In some embodiments, the pressure compensation structure 13 may include a first elastic member 131, the first elastic member 131 includes a sealed cavity, the internal air pressure of the sealed cavity is a preset pressure, and the expansion and contraction direction of the first elastic member 131 is parallel to the movable direction of the valve core 12. In some embodiments, the first elastic member 131 is disposed in the first separation cavity 112, and the first elastic member 131 may be located between the valve core 12 and the valve body 11 along the movable direction of the valve core 12.

[0041] In some embodiments, the interior of the sealed cavity may include a vacuum environment, and the preset pressure inside the sealed cavity is 0. In some embodiments, the interior of the sealed cavity may be filled with gas. In some embodiments, the preset pressure is related to the elastic coefficient and deformation state of the first elastic member 131. In some embodiments, the preset pressure only needs to make the length of the first elastic member 131 less than the distance between the valve core 12 and the valve body 11 at its position when the fluid pressure around the first elastic member 131 is not less than the critical value. In some embodiments, when the first elastic member 131 is always in a compressed state in the cavity 111, the preset pressure can be set to be smaller, for example, less than the critical value, so that when the fluid pressure around the first elastic member 131 is greater than or equal to the critical value (for example, the first pressure environment is a plain), the two ends of the first elastic member 131 will not contact the valve body 11 and the valve core 12 at the same time, and the first elastic member 131 does not participate in the opening and closing of the pressure control valve 10. In this case, when the fluid pressure around the first elastic member 131 is reduced to below the critical value, the first elastic member 131 can be further extended, so that the two ends of the first elastic member 131 contact the valve core 12 and the valve body 11 respectively, and can apply a force to the valve core 12. In some embodiments, when the first elastic member 131 is always in a stretched state in the cavity 111, the preset pressure can be set to be relatively large, for example, greater than the maximum fluid pressure in the first pressure environment, and when the fluid pressure in the first pressure environment is reduced, the first elastic member 131 can be further extended (stretched), so that the two ends of the first elastic member 131 contact the valve core 12 and the valve body 11 respectively, and can apply a force to the valve core 12. In order to facilitate the control of the first elastic member 131 applying a force to the valve core 12 when the fluid pressure around the first elastic member 131 is lower than the critical value, the preset pressure inside the sealed cavity is preferably 0 or close to 0, that is, the inside of the sealed cavity is vacuum or close to vacuum.

[0042] In this embodiment, when the fluid pressure around the first elastic member 131 decreases, the pressure difference between the internal air pressure of the sealed cavity and the external fluid pressure will cause the first elastic member 131 to stretch until the elastic force of the first elastic member 131 itself is balanced with the internal and external pressure difference of the sealed cavity or the stretching amount is limited by the distance between the valve body 11 and the valve core 12 (for example, the second length hereinafter). Since the first elastic member 131 is located between the valve core 12 and the valve body 11 along the movable direction of the valve core 12, by setting a suitable elastic coefficient and internal fluid pressure for the first elastic member 131, when the fluid pressure around the first elastic member 131 decreases below a critical value, the first elastic member 131 stretches to the two ends to contact the valve body 11 and the valve core 12 respectively, and at this time, the first elastic member 131 will apply a force to the valve core 12. Furthermore, since the expansion and contraction direction of the first elastic member 131 is parallel to the movable direction of the valve core 12 and is disposed in the first separation chamber 112 , the force applied by the first elastic member 131 to the valve core 12 will hinder the pressure control valve 10 from opening.

[0043] In some embodiments, in order to better set the performance of the pressure compensation structure 13, the interior of the sealed cavity is preferably a vacuum environment, and the internal air pressure of the sealed cavity is 0. In some embodiments, the sealed cavity can be filled with other supporting media (such as liquid, solid, etc.) or a limiting device to prevent the first elastic member 131 from being excessively deformed and easily damaged.

[0044] In some embodiments, the first elastic member 131 may be a sealed flexible component, such as a metal flexible component or a non-metallic flexible component. In some embodiments, when the pressure control valve 10 is applied to a pipeline connected to a superconducting magnet, there are certain requirements for the low temperature resistance of the pressure control valve 10, so the first elastic member 131 may be made of a metal material. In some embodiments, when the pressure control valve 10 is applied to other industrial environments and the requirements for the low temperature resistance of the pressure control valve 10 are low, it may be made of a metal or non-metallic flexible material. Exemplary non-metallic materials may include rubber, silicone, etc. In some embodiments, the first elastic member 131 may be an independent structure with a sealed cavity, such as a metal bellows. Exemplary sealing methods may include welding, bonding, or hot melt molding, etc. In some embodiments, the first elastic member 131 may be a combined cavity structure with a sealed connection, for example, a plurality of metal tubes are sealed and connected by a sealing ring. In some embodiments, Figure 5 In the illustrated embodiment, the first elastic member 131 may be a hollow cylindrical structure, and the sealing cavity of the first elastic member 131 is disposed around the side wall of the hollow cylinder.

[0045] In some embodiments, the stiffness of the first elastic member 131 can be adjusted according to actual needs. For example, if it is required that the first elastic member 131 does not provide a force to the valve core 12 that hinders the opening of the pressure control valve 10 in a preset pressure environment (such as when the fluid pressure is not lower than a critical value), the stiffness of the first elastic member 131 can be set appropriately to ensure that in the preset pressure environment, the fluid pressure around the first elastic member 131 does not cause the first elastic member 131 to stretch to contact the valve body 11 and the valve core 12 at the same time, or the fluid pressure around the first elastic member 131 causes the first elastic member 131 to stretch to slightly contact the valve body 11 and the valve core 12 (at this time, the force of the first elastic member 131 on the valve core 12 can be ignored).

[0046] In some embodiments, the number of the first elastic member 131 may be one or more. Figure 5 As shown, the number of the first elastic member 131 can be one. In another example, the number of the first elastic member 131 can be multiple, and the multiple first elastic members 131 are arranged in parallel between the valve body 11 and the valve core 12. When the fluid pressure of the first elastic member 131 is lower than the critical value, the multiple first elastic members 131 simultaneously apply force to the valve core 12.

[0047] In some embodiments, one end of the first elastic member 131 along the extension direction may be connected to the valve core 12, and the other end of the first elastic member 131 is a free end. The end of the first elastic member 131 connected to the valve core 12 may be called a fixed end. When the fluid pressure around the first elastic member 131 is lower than a critical value, the free end of the first elastic member 131 will contact the top of the first partition chamber 112 of the valve body 11, and receive a reaction force from the valve body 11, thereby applying a force to the valve core 12 to prevent the pressure control valve 10 from opening.

[0048] In some embodiments, Figure 3 and Figure 4 As shown, one end of the first elastic member 131 along the extension direction can be connected to the valve body 11, and the other end of the first elastic member 131 is a free end. For example, one end of the first elastic member 131 along the extension direction can be connected to the top of the first partition chamber 112 of the valve body 11. Among them, the end of the first elastic member 131 connected to the valve body 11 can be called a fixed end. When the fluid pressure around the first elastic member 131 is lower than the critical value, the free end of the first elastic member 131 will contact the valve core 12, thereby applying a force to the valve core 12 to prevent the pressure control valve 10 from opening.

[0049] In some embodiments, when the internal fluid pressure of the first elastic member 131 is the same as the external fluid pressure, the length of the first elastic member 131 along its own expansion and contraction direction is the initial length. For example, the interior of the first elastic member 131 is in a vacuum state, and the internal fluid pressure of the first elastic member 131 is 0 at this time. If the first elastic member 131 is in a vacuum environment, the internal fluid pressure of the first elastic member 131 is the same as the external fluid pressure, so the length of the first elastic member 131 is the initial length at this time. For the convenience of description, the following description will be based on the assumption that the internal fluid pressure of the first elastic member 131 is 0.

[0050] In some embodiments, when the internal fluid pressure of the first elastic member 131 and the external fluid pressure have a first pressure difference, the length of the first elastic member 131 along the expansion and contraction direction is a first length. In this embodiment, when the internal fluid pressure of the first elastic member 131 (i.e., the internal air pressure of the sealed cavity) and the external fluid pressure (i.e., the fluid pressure around the first elastic member 131) have a first pressure difference, the first elastic member 131 will expand and contract along the expansion and contraction direction until the deformation of the first elastic member 131 reaches a certain distance, and the elastic force of the first elastic member 131 is balanced with the first pressure difference. Figure 1 Taking the embodiment shown in the figure as an example, after the first elastic member 131 is installed in the pressure control valve 10, the fluid pressure around the first elastic member 131 (i.e., the first pressure) is greater than the internal fluid pressure of the first elastic member 131, and thus has a first pressure difference with the internal fluid pressure of the first elastic member 131. At this time, the first elastic member 131 will shrink until the first pressure difference is balanced with its own elastic force. When the first elastic member 131 shrinks to the point where the first pressure difference is balanced with its own elastic force, the length of the first elastic member 131 is the first length. In some embodiments, the first length is Figure 1 The H1 in it indicates.

[0051] In some embodiments, when the valve core 12 separates the first partition chamber 112 and the second partition chamber 113, the distance between the valve core 12 and the valve body 11 along the movable direction of the valve core 12 is a second length. In some embodiments, the second length is Figure 1 The initial length of the first elastic member 131 is greater than the second length, and the second length is greater than the first length.

[0052] In some cases, since the initial length of the first elastic member 131 is greater than the second length, it can be ensured that when the fluid pressure around the first elastic member 131 reaches a preset condition (for example, the fluid pressure around the first elastic member 131 is lower than the critical value), the first elastic member 131 can be extended to the second length, so that the two ends of the first elastic member 131 in the expansion and contraction direction are respectively in contact with the valve body 11 and the valve core 12, thereby applying a force to the valve core 12 to hinder the opening of the pressure control valve 10, ensuring that the pressure control valve 10 is not easy to open automatically in an environment where the atmospheric pressure changes suddenly (such as a sudden drop) on a plateau. Since the second length of the first elastic member 131 is greater than the first length, it can be ensured that when the fluid pressure around the first elastic member 131 does not reach the preset condition (for example, the fluid pressure around the first elastic member 131 is not lower than the critical value, and there is a first pressure difference between the fluid pressure around the first elastic member 131 and the internal fluid pressure of the first elastic member 131), when the first elastic member 131 is at the first length or greater than the first length but less than the second length, the two ends of the first elastic member 131 in the expansion and contraction direction will not contact the valve body 11 and the valve core 12 at the same time, and thus will not apply a force to the valve core 12 that hinders the opening of the pressure control valve 10, thereby ensuring that the pressure control valve 10 is maintained in a relative pressure control mode in a plain or non-atmospheric pressure sudden change environment.

[0053] In some embodiments, in order for the first elastic member 131 to provide sufficient resistance to the valve core 12 when the fluid pressure around the first elastic member 131 is lower than a critical value, the ratio of the initial length to the second length or the initial length to the first length may be greater than a preset value. In some embodiments, the ratio of the initial length to the second length or the first length may be greater than 10. In some embodiments, the ratio of the initial length to the second length or the first length may be greater than 15. In some embodiments, the ratio of the initial length to the second length or the first length may be greater than 20. In some embodiments, in order for the pressure control valve 10 to achieve a relative pressure control mode within a suitable pressure range, the difference between the second length and the first length may be in the range of 1 mm to 5 mm. In some embodiments, the difference between the second length and the first length may be in the range of 5 mm to 10 mm. In some embodiments, the difference between the second length and the first length may be in the range of 10 mm to 50 mm.

[0054] In some embodiments, the pressure control valve 10 may further include a seal 14, which may be disposed between the valve body 11 and the valve core 12. When the valve core 12 moves, it can drive the seal 14 to move, thereby isolating the first fluid connecting port 114 and the second fluid connecting port 115, or it can drive the seal 14 to move, thereby connecting the first fluid connecting port 114 and the second fluid connecting port 115.

[0055] In some embodiments, the seal 14 may be a component that adopts a sealing form such as an end face, a step, etc., for example, a sealing gasket, a sealing ring (such as Figure 1 As shown), tongue and groove sealing components, concave and convex sealing components, etc. The seal 14 in the form of end face, step, etc. has good sealing performance and is not easy to wear. In some embodiments, the seal 14 can be a component in the form of side seal, such as a sealing ring. In some embodiments, the number of seals 14 can be one. For example, in Figure 1 In the embodiment shown, the sealing member 14 can be a sealing ring, and the number of the sealing ring is one. The sealing ring is located on a side of the first valve core 121 close to the second valve core 122 and is disposed around the second valve core 122. In some embodiments, the number of the sealing member 14 can be multiple. Figure 1 On the basis of the shown embodiment, an additional sealing gasket can be provided. The additional sealing gasket can be provided on the side of the first valve core 121 close to the second valve core 122 and located inside the sealing ring. When the first valve core 121 moves toward the second separation chamber 113, the sealing ring and the sealing gasket can simultaneously contact the bottom of the first separation chamber 112, thereby achieving sealing.

[0056] In some embodiments, the seal 14 can be disposed between the first valve core 121 and the first separation chamber 112. For example, the seal 14 can be disposed on the side of the first valve core 121 close to the second separation chamber 113. Since the cross-sectional area of ​​the first valve core 121 is larger than the cross-sectional area of ​​the second separation chamber 113, when the first valve core 121 moves toward the second separation chamber 113, the first valve core 121 can press the seal 14 against the bottom of the first separation chamber 112, thereby achieving sealing through the seal 14.

[0057] In some embodiments, the seal 14 can be disposed between the second valve core 122 and the second separation chamber 113. For example, the seal 14 can be disposed on the side wall of the second valve core 122 close to the first valve core 121. When the first valve core 121 moves toward the second separation chamber 113, the seal 14 on the side wall of the second valve core 122 can abut against the bottom of the first separation chamber 112 (or the top of the second separation chamber 113), thereby achieving sealing.

[0058] In some embodiments, the pressure-bearing area of ​​the first elastic member 131 in the expansion and contraction direction is the first area, the sealing cross-sectional area of ​​the sealing member 14 in the expansion and contraction direction of the first elastic member 131 is the second area, and the absolute value of the difference between the first area and the second area is less than a preset value. The pressure-bearing area refers to the cross-sectional area of ​​the contact surface between the first elastic member 131 and the valve body 11 or the valve core 12. For example, Figure 1 As shown, when the first elastic member 131 is a metal bellows, the pressure-bearing area can be equal to the cross-sectional area of ​​the metal bellows in the expansion and contraction direction. Figure 5As shown, when the first elastic member 131 is a hollow cylindrical structure, its sealing cavity is annular, so the pressure-bearing area of ​​the hollow cylindrical structure is equal to the difference between the cross-sectional area in the telescopic direction and the hollow cross-sectional area. The cross-sectional area of ​​the hollow cylindrical structure in the telescopic direction can be calculated by Figure 5 The sealing cross-sectional area is represented by S3 in the figure, and the hollow cross-sectional area can be represented by S4. The sealing cross-sectional area refers to the cross-sectional area of ​​the seal of the seal 14. For example, when the seal 14 is a sealing ring, the sealing cross-sectional area can be equal to the circular cross-sectional area formed by the sealing ring. In some embodiments, the ratio of the preset value to the first area or the second area can be less than or equal to 20%. In some embodiments, the ratio of the preset value to the first area or the second area can be less than or equal to 10%. In some embodiments, the ratio of the preset value to the first area or the second area can be less than or equal to 5%. In some preferred embodiments, the first area and the second area are the same.

[0059] In some cases, when the fluid pressure around the first elastic member 131 drops below a critical value, the opening and closing of the pressure control valve 10 can be substantially unaffected by the atmospheric pressure, even if the pressure control valve 10 operates in an absolute pressure control mode.

[0060] In some embodiments, when there are multiple seals 14 and / or first elastic members 131, the expansion and contraction directions of the multiple first elastic members 131 are parallel, the first area is the sum of the pressure-bearing areas of the multiple first elastic members 131 in the expansion and contraction directions, and the second area is the sum of the sealing cross-sectional areas of the multiple seals 14 in the expansion and contraction directions of the first elastic members 131.

[0061] In some embodiments, the pressure control valve 10 may further include a second elastic member 15, one end of the second elastic member 15 is connected to the valve core 12, and the other end is directly or indirectly connected to the valve body 11, and the second elastic member 15 has a preset preload force. In some embodiments, the preload force of the second elastic member 15 is used to prevent the pressure control valve 10 from opening.

[0062] In this embodiment, since the second elastic member 15 has a preset pre-tightening force, when the first pressure environment is a plain or non-atmospheric pressure sudden change environment, the valve core 12 is subjected to the combined force of the first pressure, the second pressure and the pre-tightening force of the second elastic member 15, and the pressure control valve 10 is in a relative pressure control mode. When the internal air pressure of the superconducting magnet (i.e., the gas pressure in the inner container cavity of the superconducting magnet) is stable, the pre-tightening force provided by the second elastic member 15 can act on the valve core 12 so that the sealing member 14 isolates the first separation chamber 112 and the second separation chamber 113, that is, closes the valve. When the internal air pressure of the superconducting magnet increases, the internal air pressure of the superconducting magnet is greater than the sum of the atmospheric pressure and the pre-tightening force. At this time, the valve core 12 will overcome the pre-tightening force of the second elastic member 15 to drive the sealing member 14 to move, until the second elastic member 15 reaches a certain deformation amount, so that the sealing member 14 loses the sealing effect, the first separation chamber 112 and the second separation chamber 113 are connected, that is, the valve is opened for pressure relief. When the pressure relief is completed and the internal air pressure of the superconducting magnet is again less than the sum of the force exerted on the valve core 12 by the atmospheric pressure and the preload force, the valve core 12 will be driven back by the elastic force of the second elastic member 15 and press the sealing member 14 to close the valve again.

[0063] In some embodiments, the second elastic member 15 will deform when the valve core 12 and the first elastic member 131 move, and the maximum deformation of the second elastic member 15 can be less than the difference between the second length and the first length, that is, the two ends of the first elastic member 131 do not contact the valve body 11 and the valve core 12 at the same time, so that the first elastic member 131 will not apply additional force to the valve core 12 during this process, so that the pressure control valve 10 always operates in a relative pressure control mode.

[0064] In some embodiments, the second elastic member 15 may be disposed in the second partition chamber 113, one end of the second elastic member 15 is connected to the bottom of the second valve core 122, and the other end of the second elastic member 15 is directly or indirectly connected to the bottom of the second partition chamber 113 of the valve body 11. In some embodiments, the second elastic member 15 may be disposed in the first partition chamber 112. For example only, Figure 5 As shown, the first elastic member 131 is a hollow cylindrical structure, the second elastic member 15 is located in the hollow cavity of the hollow cylinder, one end of the second elastic member 15 can be connected to the top of the first valve core 121, and the other end of the second elastic member 15 is directly or indirectly connected to the top of the first separation cavity 112. Since the second elastic member 15 is located in the hollow cavity of the first elastic member 131, the pressure control valve 10 has a more compact structure and a simpler design.

[0065] In some embodiments, the second elastic member 15 may be directly connected to the valve body 11 by bonding, hinged connection, snap connection, welding, etc. In some embodiments, the second elastic member 15 may be indirectly connected to the valve body 11 by the preload force applying device 16 described below.

[0066] In some embodiments, the second elastic member 15 may include a spring, such as a compression spring, a tension spring or a torsion spring, etc. In some embodiments, the second elastic member 15 may include a composite material structure such as an elastic bellows, an elastic rubber, an airbag, etc.

[0067] In some embodiments, the stiffness of the first elastic member 131 may be smaller than the stiffness of the second elastic member 15. When the stiffness of the first elastic member 131 is smaller than the stiffness of the second elastic member 15, the overall stiffness of the pressure control valve 10 in the absolute pressure control mode is close to the overall stiffness of the pressure control valve 10 in the relative pressure control mode. The pressure at which the pressure control valve 10 opens and the pressure fluctuation inside the magnet will not be too large, which can improve the stability of the pressure control valve 10 during operation.

[0068] In some embodiments, the preload force of the second elastic member 15 can be a fixed value. For example, the other end of the second elastic member 15 is directly fixedly connected to the valve body 11, and the preload force of the second elastic member 15 cannot be adjusted. In some embodiments, when the pressure control valve 10 is in a relative pressure control mode, the second pressure required for opening the pressure control valve 10 (i.e., the pressure in the inner container cavity of the superconducting magnet) is positively correlated with the preload force, and the preload force of the second elastic member 15 can be adjusted according to actual conditions. For example, if you want to avoid helium leakage in the superconducting magnet as much as possible, you can increase the preload force, so that a larger second pressure is required to open the pressure control valve 10. For another example, if you want to reduce the air pressure in the superconducting magnet, you can reduce the preload force, so that only a smaller second pressure is required to open the pressure control valve 10.

[0069] In some embodiments, the pressure control valve 10 further includes a preload applying device 16, and the other end of the second elastic member 15 can be connected to the valve body 11 through the preload applying device 16, and the preload applying device 16 can be used to apply or adjust the preload of the second elastic member 15. In some embodiments, the preload applying device 16 can include a tensioning member 161 and a locking member 162, and the other end of the second elastic member 15 is connected to the tensioning member 161 and is movably connected to the valve body 11 through the locking member 162, and the movement of the tensioning member 161 can change the tension of the second elastic member 15. For example, in Figure 1 In the embodiment shown, one end of the second elastic member 15 is connected to the second valve core 122, so the locking member 162 is arranged at the bottom of the second partition cavity 113, one end of the tensioning member 161 extends into the second partition cavity 113 and is connected to the second elastic member 15, and the other end is movably connected to the bottom of the second partition cavity 113 of the valve body 11 through the locking member 162. Figure 5In the illustrated embodiment, one end of the second elastic member 15 is connected to the first valve core 121, so the locking member 162 is arranged at the top of the first partition chamber 112, one end of the tensioning member 161 extends into the first partition chamber 112 and is connected to the second elastic member 15, and the other end is movably connected to the top of the first partition chamber 112 of the valve body 11 through the locking member 162.

[0070] In some embodiments, the preload force applying device 16 may include a threaded structure, a snap-fit ​​structure, a worm gear structure, etc. As an example only, the tensioning member 161 may be a screw tensioning member, and the locking member 162 may be a nut locking member, the nut locking member is connected to the bottom of the valve body 11, one end of the screw tensioning member 161 is connected to the second elastic member 15, and the other end is connected to the nut locking member. When the screw tensioning member or the nut locking member is rotated, the second elastic member 15 can be driven to compress or extend, thereby changing the preload force of the second elastic member 15.

[0071] In some embodiments, the preload force applying device 16 may further include a sealing structure 163, which may be enclosed outside the tensioning member 161 and the locking member 162 to isolate the tensioning member 161 and the locking member 162 from the external environment. Figure 1 As shown, the sealing structure 163 may include a sealing cover 164 and a second sealing member 165. The sealing cover 164 is disposed on the bottom outer side of the first partition chamber 112 of the valve body 11. One end of the screw tensioner and the nut locking member are both located inside the sealing cover 164. The sealing cover 164 and the bottom outer side of the first partition chamber 112 of the valve body 11 are sealed by the second sealing member 165 to ensure that the screw tensioner and the nut locking member are isolated from the external environment. In some embodiments, the second sealing member 165 may be the same as or similar to the sealing member 14 in other embodiments of the present specification. For example, the second sealing member 165 may be a sealing ring or a sealing ring.

[0072] In order to more clearly explain how the pressure control valve 10 is opened or closed under different external pressure environments, and how to switch between the relative pressure control mode and the absolute pressure control mode, this specification will be combined with Figure 1 and Figure 2 The motion state of the pressure control valve 10 is analyzed.

[0073] When the first pressure environment is a plain and non-atmospheric pressure sudden change environment, the fluid pressure around the pressure compensation structure 13 remains almost unchanged, and the internal fluid pressure of the first elastic member 131 of the pressure compensation structure 13 has a first pressure difference with the external fluid pressure, and the first elastic member 131 will be compressed to the first length, and then the elastic force of the first elastic member 131 at the first length can be obtained: F10=(P1-b)*S1=K1*(H0-H1) (1) Wherein, S1 is the pressure-bearing area of ​​the first elastic member 131 in the extension direction. K1 is the stiffness of the first elastic member 131. H0 is the initial length of the first elastic member 131. H1 is the first length of the first elastic member 131. P1 is the fluid pressure outside the first elastic member 131, for example, atmospheric pressure. P1*S1 is the fluid pressure around the first elastic member 131. b is the fluid pressure inside the first elastic member 131. In some embodiments, when the internal fluid pressure of the first elastic member 131 is 0, the value of b is 0, so it can be further concluded from (1): F10=(P1-0)*S1=K1*(H0-H1) (2)

[0074] In some embodiments, the first length is less than the second length, so the two ends of the first elastic member 131 in the expansion and contraction direction are not in contact with the valve body 11 and the valve core 12 at the same time, and the first elastic member 131 does not provide a force to the valve core 12 that hinders the opening of the pressure control valve 10. At this time, whether the pressure control valve 10 is opened or closed depends on the internal gas pressure of the container in the superconducting magnet. To open the pressure control valve 10, the following conditions must be met: P2=(K2*ΔL2+P1*S2) / S2 (3) Wherein, P2 is the internal fluid pressure of the superconducting magnet. K2 is the stiffness of the second elastic member 15. ΔL2 is the deformation of the second elastic member 15 when the sealing member 14 is separated from the valve body 11 and loses the sealing function. S2 is the sealing cross-sectional area of ​​the sealing member 14.

[0075] When the internal air pressure of the superconducting magnet is less than the fluid pressure and preload around the pressure compensation structure 13, the second elastic member 15 will drive the valve core 12 to press the seal 14, so that the first partition chamber 112 and the second partition chamber 113 are isolated, and the pressure control valve 10 is closed. When the internal air pressure of the superconducting magnet is greater than the fluid pressure and preload around the pressure compensation structure 13, the valve core 12 will overcome the preload of the second elastic member 15 and move until the deformation of the second elastic member 15 is ΔL2, which may cause the seal 14 to lose its sealing function. At this time, the first partition chamber 112 and the second partition chamber 113 are connected, and the pressure control valve 10 is opened. When the internal air pressure of the superconducting magnet is less than the fluid pressure and preload around the pressure compensation structure 13 again, the valve core 12 will be driven by the elastic force of the second elastic member 15 to retreat and press the seal 14, so that the valve is closed again. During this process, the maximum deformation of the second elastic member 15 is less than the difference between the second length and the first length, that is, the first elastic member 131 never contacts the valve body 11 and the valve core 12 at the same time, and no additional force acts on the valve core 12.

[0076] When the fluid pressure of the first pressure environment is less than the critical value, the fluid pressure around the pressure compensation structure 13 is also less than the critical value. As an example, during the take-off and landing of a cargo plane carrying superconducting magnets, the cabin pressure is reduced to 60% of the pressure before take-off, and the pressure is less than the critical value. It can be determined that the pressure reduction value of the first pressure environment acting on the valve core 12 is: Fd=(P1-0.6*P1)*S2=0.4*P1*S2 (4)

[0077] If the pressure compensation structure 13 is not provided, the pressure control valve 10 is opened only when: P2=(K2*ΔL2+0.6*P1*S2) / S2 (5)

[0078] It can be seen from formula (5) that, when the pressure compensation structure 13 is not provided, the internal gas pressure of the superconducting magnet required to open the pressure control valve 10 will be reduced, which may cause a sudden release of helium inside the superconducting magnet, thereby causing unnecessary losses.

[0079] After the pressure compensation structure 13 is set, when the fluid pressure around the pressure compensation structure 13 decreases, the first elastic member 131 is stretched. When the deformation of the first elastic member 131 is equal to the difference between the second length and the first length, both ends of the first elastic member 131 in the expansion and contraction direction are in contact with the valve body 11 and the valve core 12 at the same time, and cannot be stretched any further. At this time, the first elastic member 131 reaches a balance under the combined action of its own elastic force, the difference between the internal fluid pressure of the first elastic member 131 and the external fluid pressure, and the force of the valve body 11. When the preset pressure of the internal air pressure of the pressure compensation structure 13 is 0, the force of the pressure compensation structure 13 satisfies the following relationship: Fv+(0.6*P1-0)*S1=K1*(H0-H2) (6) Wherein, Fv is the force exerted by the valve body 11 on the first elastic member 131 .

[0080] In some embodiments, when the initial length H0 is much greater than the second length H2 (for example, the ratio of H0 to H2 is greater than 10), or the initial length H0 is much greater than the first length H1 (for example, the ratio of H0 to H1 is greater than 10) and the difference between the first length H1 and the second length H2 is small, the difference between H0 and H1 or H2 is approximately equal to H0. In this case, equations (2) and (6) can be further simplified as follows: F10=P1*S1=K1*H0 (7) Fv+(0.6*P1-0)*S1=K1*H0 (8)

[0081] Combining equation (7) and equation (8), we can further derive: Fv=0.4*P1*S1 (9)

[0082] In some embodiments, when the pressure bearing area S1 of the first elastic member 131 is the same as or close to the sealing cross-sectional area S2 of the sealing member 14, it can be obtained from equations (9) and (4): Fv=0.4*P1*S1=0.4*P1*S2=Fd (10)

[0083] It can be seen from formula (10) that the first elastic member 131 will generate a force Fv on the valve core 12 that hinders the opening of the pressure control valve 10, and the force is approximately equal to the value Fd of the pressure reduction of the first pressure environment on the valve core 12. Therefore, at this time, opening the pressure control valve 10 needs to meet the following conditions: P2=(K2*ΔL2+0.6*P1*S2+Fv) / S2=(K2*ΔL2+P1*S2) / S2 (11)

[0084] It can be seen from formula (11) that even if the gas pressure of the first pressure environment changes to 60% of P1, the pressure required to open the pressure control valve 10 at this time is still only related to the gas pressure P1 of the first pressure environment before the change, that is, the pressure required to open the pressure control valve 10 at this time is not affected by the change of the first pressure environment, and it is an absolute pressure control mode. In this mode, the pressure control valve will not suddenly release a large amount of gas due to the pressure change of the first pressure environment, and unnecessary helium escape can be avoided.

[0085] The beneficial effects of the pressure control valve provided in this specification include but are not limited to: (1) by setting a pressure compensation structure, the pressure control valve can operate in a relative pressure control mode when the first pressure environment is a plain environment or a non-atmospheric mutation environment, so that the pressure control valve can switch from a relative pressure control mode to an absolute pressure control mode when the first pressure environment is a plateau environment or an atmospheric mutation environment, so that the pressure control valve can flexibly control the gas pressure of the superconducting magnet (that is, the gas pressure in the inner container cavity of the superconducting magnet) and is not affected by changes in external environmental pressure; (2) when the stiffness of the first elastic member is less than the stiffness of the second elastic member, the overall stiffness of the pressure control valve in the absolute pressure control mode is close to the overall stiffness of the pressure control valve in the relative pressure control mode, and the pressure at which the pressure control valve is opened and the pressure fluctuation inside the magnet will not be too large, which can improve the pressure control The stability of the valve during operation; (3) when the fluid pressure around the first elastic member drops below the critical value, the first elastic member will compensate the valve core pressure (i.e., apply a force), and the value of the pressure compensation is equal to the product of the fluid pressure change and the ratio of the first area to the second area. Therefore, when the absolute value of the difference between the first area and the second area is less than the preset value, the value of the pressure compensation and the value of the fluid pressure reduction around the first elastic member are within the preset range, so that the pressure at which the pressure control valve is opened will not fluctuate too much in the two modes, thereby improving the stability of the pressure control valve during operation; (4) in the relative pressure control mode, the maximum deformation of the second elastic member needs to be less than the difference between the second length and the first length, that is, the two ends of the first elastic member do not contact the valve body and the valve core at the same time, so that the first elastic member will not apply additional force to the valve core during this process, so that the pressure control valve always works in the relative pressure control mode.

[0086] The above description is only a preferred embodiment of this specification and is not intended to limit this specification. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this specification should be included in the protection scope of this specification.

Claims

1. A pressure control valve (10), characterized in that: include: A valve body (11) comprising a cavity (111) and a first fluid communication port (114) and a second fluid communication port (115) for connecting the cavity (111) to the outside of the valve body (11); A valve core (12) is movably disposed in the cavity (111), and the valve core (12) moves so that the first fluid communication port (114) and the second fluid communication port (115) are connected or disconnected; A pressure compensation structure (13) is arranged between the valve core (12) and the valve body (11); when the fluid pressure around the pressure compensation structure (13) is lower than a critical value, the pressure compensation structure (13) provides a force to the valve core (12) to prevent the pressure control valve (10) from opening.

2. The pressure control valve (10) according to claim 1, characterized in that: The pressure compensation structure (13) comprises a first elastic member (131), the first elastic member (131) comprises a sealed cavity, the internal air pressure of the sealed cavity is a preset pressure, and the expansion and contraction direction of the first elastic member (131) is parallel to the movable direction of the valve core (12).

3. The pressure control valve (10) according to claim 2, characterized in that: The cavity (111) comprises a first separation cavity (112) and a second separation cavity (113); the first separation cavity (112) is in communication with the first fluid communication port (114), and the second separation cavity (113) is in communication with the second fluid communication port (115); the valve core (12) moves so that the first separation cavity (112) and the second separation cavity (113) are in communication or disconnected; the first elastic member (131) is arranged in the first separation cavity (112), and is located between the valve core (12) and the valve body (11) along the movable direction of the valve core (12).

4. The pressure control valve (10) according to claim 3, characterized in that: When the internal fluid pressure of the first elastic member (131) is the same as the external fluid pressure, the length of the first elastic member (131) along the expansion and contraction direction is an initial length; when the internal fluid pressure of the first elastic member (131) and the external fluid pressure have a first pressure difference, the length of the first elastic member (131) along its own expansion and contraction direction is a first length; when the valve core (12) separates the first separation chamber (112) and the second separation chamber (113), the distance between the valve core (12) and the valve body (11) along the movable direction of the valve core (12) is a second length, the initial length of the first elastic member (131) is greater than the second length, and the second length is greater than the first length.

5. The pressure control valve (10) according to claim 3, characterized in that: The valve core (12) comprises a first valve core (121), the first valve core (121) is located in the first separation chamber (112), and along a movable direction perpendicular to the valve core (12), a cross-sectional area of ​​the first valve core (121) is greater than a cross-sectional area of ​​the second separation chamber (113).

6. The pressure control valve (10) according to claim 3, characterized in that: The valve core (12) comprises a first valve core (121) and a second valve core (122) connected to the first valve core (121); the first valve core (121) is located in the first separation chamber (112); the second valve core (122) is at least partially located in the second separation chamber (113); at the connection between the first valve core (121) and the second valve core (122), along a movable direction perpendicular to the valve core (12), the cross-sectional area of ​​the first valve core (121) is greater than the cross-sectional area of ​​the second valve core (122); and the cross-sectional area of ​​the first valve core (121) is greater than the cross-sectional area of ​​the second separation chamber (113).

7. The pressure control valve (10) according to claim 3, characterized in that: It also includes a sealing member (14), wherein the sealing member (14) is arranged between the valve body (11) and the valve core (12); The pressure-bearing area of ​​the first elastic member (131) in the telescopic direction is a first area, the sealing cross-sectional area of ​​the sealing member (14) in the telescopic direction of the first elastic member (131) is a second area, and the absolute value of the difference between the first area and the second area is less than a preset value.

8. The pressure control valve (10) according to claim 1, characterized in that: One end of the first elastic member (131) along the extension direction is connected to the valve core (12), and the other end is a free end; And / or, one end of the first elastic member (131) along the telescopic direction is connected to the valve body (11), and the other end is a free end.

9. The pressure control valve (10) according to any one of claims 1 to 8, characterized in that: It also comprises a second elastic member (15), one end of the second elastic member (15) is connected to the valve core (12), and the other end is directly or indirectly connected to the valve body (11); the second elastic member (15) has a preset preload force.

10. The pressure control valve (10) according to claim 9, characterized in that The valve body (11) further comprises a preload force applying device (16), wherein the preload force applying device (16) comprises a tensioning member (161) and a locking member (162), wherein the tensioning member (161) is connected to the other end of the second elastic member (15) and is movably connected to the valve body (11) via the locking member (162), and movement of the tensioning member (161) changes the preload force of the second elastic member (15).

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