WO2022057177A1

WO2022057177A1 - Dual valve-structured low-temperature pump

Info

Publication number: WO2022057177A1
Application number: PCT/CN2021/072640
Authority: WO
Inventors: 常振旗; 赵保旭
Original assignee: 中国科学技术大学
Priority date: 2020-09-16
Filing date: 2021-01-19
Publication date: 2022-03-24
Also published as: CN112096597B; CN112096597A

Abstract

A dual valve-structured low-temperature pump, comprising a pump body, a sleeve pipe, a main valve base (9), a main valve rod, a main valve door (11), a main driver (8), a front valve base (10), a front valve rod, a front valve door (14), a front driver (7), a sealing and locking apparatus, a primary condensation-adsorption apparatus (4), and a secondary condensation-adsorption apparatus (5). The front valve base (10), the front valve door (14), the main valve door (11), the main valve base (9) are provided sequentially. The main valve base (9) is provided at the front end of the pump body. The primary condensation-adsorption apparatus (4) and the secondary condensation-adsorption apparatus (5) are arranged within the pump body. The sleeve pipe runs through the pump body. The main valve rod is movably provided in the sleeve pipe. The front valve rod is movably provided in the main valve rod. The front valve base (10) is provided on a docking opening of a conduit (12) in communication with the pump body. When a fault occurs, the front driver (7) drives the front valve door (14) via the front valve rod to move onto the front valve base (10), the sealing and locking apparatus sealedly fixes the front valve door (14) to the front vale base (10), thus severing communication with the conduit (12), the primary driver (8) drives the main valve door (11) via the main valve rod onto the main valve base (9) so as to seal the pump body, and the faulty pump body is replaced, thus implementing the replacement of a faulty low-temperature pump without stopping a nuclear reactor.

Description

A cryopump with double valve structure

This application claims the priority of the Chinese patent application filed on September 16, 2020 with the application number 202010972917.3 and the title of the invention is "a cryopump with dual valve structure", the entire contents of which are incorporated herein by reference middle.

technical field

The invention belongs to the technical field of nuclear fusion equipment, and more particularly relates to a cryogenic pump with a double valve structure.

Background technique

The development of industry is inseparable from energy, and nuclear energy is the main pillar of future energy because of its cleanness and abundant fuel resources. Fusion energy, as one of nuclear energy, is pinned to end the energy crisis. The tokamak device is one of the most effective means to study fusion at present, and relevant researches are currently being carried out in the developed countries in the world. As the world's largest energy-consuming country and a powerful country in science and technology, China's research on fusion energy has always been at the world's advanced level. At present, the EAST tokamak device built in China ranks first in the world.

While actively participating in ITER (International Thermonuclear Fusion Experimental Reactor) research, China is also carrying out research work on the next-generation advanced fusion reactor CFETR (China Fusion Engineering Experimental Reactor), aiming to build an advanced, safe and reliable fusion experimental device. Remove technical barriers to the successful establishment of future commercial demonstration power plants.

The main engine of CFETR is a large tokamak device, in which deuterium and tritium fuels undergo fusion reactions to release energy. Due to the limitation of combustion rate, most of the fuels need to be discharged before they can react. The reaction part produces helium particles that affect the stability of the plasma. These particles interact with the divertor target plate to form neutral gas particles, and are discharged with unreacted deuterium-tritium gas. A cryopump was selected as the main vacuum pump for CFETR due to its high pumping speed and no rotating parts. The entire vacuum system of CFETR consists of several cryopumps, which provide stable pumping speed and vacuum degree through alternate operation.

At present, most of the commercial cryopumps are foreign products, and most of them use the structure of low temperature cold head to cool the low temperature baffle. Although the efficiency is high, the pumping volume is small and the electrical equipment is easy to fail in the environment of strong irradiation and strong magnetic field. After more than 20 years of design and research, the ITER cryopump can adapt to the operation under fusion conditions, but compared with the ITER, the CFETR has higher physical parameters and a larger load factor, which means that the continuous operation time of the CFETR is longer. Exhaust volume is larger. From the point of view of continuous operation, the safety and functionality of the ITER cryopump can no longer meet the requirements of CFETR.

Therefore, how to provide a cryopump with a double valve structure so as to realize the non-stop replacement of the faulty cryopump in the nuclear reactor is a technical problem to be solved urgently by those skilled in the art.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a cryopump with a double valve structure, so as to realize the non-stop replacement of a faulty cryopump in a nuclear reactor.

In order to achieve the above object, the present invention provides the following technical solutions:

A cryogenic pump with a double valve structure, comprising a pump body, a casing, a main valve seat, a main valve stem, a main valve, a main driver, a front valve seat, a front valve stem, a front valve, a front driver, a sealing locking device, a Stage condensation adsorption device and secondary condensation adsorption device, wherein,

The main valve seat is located at the front end of the pump body, the main valve is located at the front end of the main valve seat, the front valve is located at the front end of the main valve, and the front valve seat is located at the front end of the front valve. front end,

The primary condensation adsorption device and the secondary condensation adsorption device are built in the pump body, and the inlet and outlet of the supercritical helium pipeline of the primary condensation adsorption device and the secondary condensation adsorption device are connected to the pump rear end of the body,

The sleeve passes through the front and rear ends of the pump body, the main valve stem is set in the sleeve for moving, the front valve stem is moved and set in the main valve stem, and the main valve stem is moved. a valve stem is connected with the main driver, the front valve stem is connected with the front driver,

The main valve is arranged at the end of the main valve stem, the front valve is arranged at the end of the front valve stem,

The front valve seat is arranged on the butting port of the pipeline communicating with the pump body,

Under normal conditions,

When the pump body is opened, the front valve and the main valve are located between the main valve seat and the front valve seat, the pipeline is communicated with the pump body, and the gas from the pipeline enters the pump body. After the pump body is described, the first cooling condensation adsorption is carried out through the first-stage condensation adsorption device, and then the remaining difficult-to-condensable gas is subjected to the second cooling condensation adsorption through the second-stage condensation adsorption device,

When a failure occurs,

The front driver drives the front valve to move to the front valve seat through the front valve rod, and the sealing locking device seals and fixes the front valve on the front valve seat, cutting off the connection with the pipeline. connection,

The main driver drives the main valve to move to the main valve seat to seal the pump body through the main valve rod, so as to replace the faulty pump body.

Preferably, the above-mentioned sealing and locking device comprises an axial ejector rod, a radial ejector rod and a plug which are connected in sequence,

Under normal conditions,

The radial ejector rod and the ejector head avoid the movement path of the front valve,

When a failure occurs,

The rotation of the axial ejector rod drives the plug head to the rear end of the front valve through the radial ejector rod, and the axial ejector rod exerts an axial thrust so that the plug head pushes the front valve against the The front valve seat is sealed and fixed.

Preferably, the above-mentioned sealing and locking devices are multiple and uniformly arranged around the front valve seat.

Preferably, the outer casing of the axial ejector is provided with a bellows.

Preferably, the front valve and the front valve stem are detachably connected,

Exceeding a critical axial pulling force disengages the front valve from the front valve stem, and exceeding a critical axial thrust force connects the front valve and the front valve stem.

Preferably, the above-mentioned main driver is built in the sleeve,

The front driver is connected with the main valve stem.

Preferably, the main driver and the front driver are both pneumatic.

Preferably, the surface of the above-mentioned secondary condensation adsorption device is coated with activated carbon.

Preferably, the front end of the pump body is provided with a front flange, and the main valve seat is provided on the front flange,

The rear end of the pump body is provided with a rear flange,

The rear flange is provided with the inlet and outlet sub-flange ports of the liquid helium pipeline of the primary condensation adsorption device, the inlet and outlet sub-flange ports of the supercritical helium pipeline of the secondary condensation adsorption device, and the sub-flange ports of the detection equipment. .

Preferably, the inner surface of the pump body is covered with a heat shield.

The cryogenic pump with double valve structure provided by the present invention includes a pump body, a casing, a main valve seat, a main valve stem, a main valve, a main driver, a front valve seat, a front valve stem, a front valve, a front driver, and a sealing locking device , a primary condensation adsorption device and a secondary condensation adsorption device, wherein,

Under normal conditions,

When a failure occurs,

So as to realize the non-stop replacement of faulty cryopumps in nuclear reactors.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

1 is a schematic cross-sectional structural diagram of a cryopump with a dual-valve structure provided by an embodiment of the present invention;

2 is a schematic structural diagram of a sealing and locking device provided by an embodiment of the present invention;

3 is a schematic structural diagram of the sealing and locking device provided by the embodiment of the present invention when the front valve is locked;

4 is a schematic structural diagram when the front valve provided by the embodiment of the present invention is not located in the front valve and the main valve is located in the main valve seat;

FIG. 5 is a schematic structural diagram when the front valve is located in the front valve and the main valve is not located in the main valve seat according to an embodiment of the present invention.

In Figure 1-5 above:

Cryopump enclosure 1, axial ejector 2, heat shield 3, primary condensation adsorption device 4, secondary condensation adsorption device 5, rear flange 6, front driver 7, main driver 8, main valve seat 9, front Valve seat 10 , main valve 11 , pipeline 12 , plug 13 , front valve 14 , radial ejector rod 15 , bellows 16 .

detailed description

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Please refer to FIGS. 1 to 5. FIG. 1 is a schematic cross-sectional structural diagram of a cryopump with a double valve structure provided by an embodiment of the present invention; FIG. 2 is a schematic structural diagram of a sealing locking device provided by an embodiment of the present invention; A schematic structural diagram of the sealing and locking device provided in the embodiment of the invention when the front valve is locked; FIG. 4 is a schematic structural diagram of the front valve provided in the embodiment of the present invention when the front valve is not located in the front valve and the main valve is located in the main valve seat; FIG. 5 is a schematic diagram of the structure. The embodiment of the present invention provides a schematic structural diagram when the front valve is located in the front valve and the main valve is not located in the main valve seat.

The cryopump with dual valve structure provided by the embodiment of the present invention includes a pump body, a casing, a main valve seat 9, a main valve stem, a main valve 11, a main driver 8, a front valve seat 10, a front valve stem, a front valve 14, Front driver 7, sealing locking device, primary condensation adsorption device 4 and secondary condensation adsorption device 5, wherein, primary condensation adsorption device 4 can be 80K shutter baffle, secondary condensation adsorption device 5 can be 4.5K cryopanel ,

The main valve seat 9 is located at the front end of the pump body, the main valve 11 is located at the front end of the main valve seat 9, the front valve 14 is located at the front end of the main valve 11, the front valve seat 10 is located at the front end of the front valve 14,

The primary condensation adsorption device 4 and the secondary condensation adsorption device 5 are built in the pump body, and the inlet and outlet of the supercritical helium pipeline of the primary condensation adsorption device 4 and the secondary condensation adsorption device 5 are connected to the rear end of the pump body,

The casing passes through the front and rear ends of the pump body, the main valve stem is set in the casing, the front valve stem is set in the main valve stem, the main valve rod is connected with the main driver, and the front valve rod is connected with the front driver ,

The main valve 11 is arranged at the end of the main valve stem, the front valve 14 is arranged at the end of the front valve stem,

The front valve seat 10 is arranged on the opposite port of the pipeline 12 communicating with the pump body,

Under normal conditions,

When the pump body is opened, the front valve 14 and the main valve 11 are located between the main valve seat 9 and the front valve seat 10, and the pipeline 12 is connected to the pump body. After the gas from the pipeline enters the pump body, it first passes through the primary condensation adsorption device 4. The first cooling condensation adsorption is carried out, and then the remaining difficult-to-condensable gas is subjected to the second cooling condensation adsorption through the secondary condensation adsorption device 5,

When a failure occurs,

The front driver 7 drives the front valve 14 to move to the front valve seat 10 through the front valve stem, and the sealing locking device seals and fixes the front valve 14 on the front valve seat 10, cutting off the communication with the pipeline 12,

The main driver 8 drives the main valve 11 through the main valve stem to move to the main valve seat 9 to seal the pump body, and replace the faulty pump body.

In order to further optimize the above solution, the sealing and locking device includes an axial ejector rod 2, a radial ejector pin 15 and a header 13 connected in sequence, as shown in FIG. 2,

Under normal conditions,

The radial ejector rod 15 and the ejector head 13 avoid the moving path of the front valve 14,

When a failure occurs,

The axial ejector rod 2 rotates through the radial ejector rod 15 to drive the plug head 13 to the rear end of the front valve 14, and the axial ejector rod 2 exerts an axial thrust so that the plug head 13 presses the front valve 14 on the front valve seat 10 and seals and fixes it, such as shown in Figure 3.

Specifically, there are multiple sealing and locking devices and are evenly arranged around the front valve seat 10 . A bellows 16 is provided on the outer casing of the axial ejector rod 2 .

In order to further optimize the above solution, the front valve 14 and the front valve stem are detachably connected,

Exceeding a critical axial pulling force causes the front valve 14 to separate from the front valve stem, and exceeding a critical axial thrust force causes the front valve 14 to connect with the front valve stem. Then, when the faulty pump body needs to be disassembled, the front valve stem seals the front valve 14 to the pipeline 12 and then moves back directly to be separated from the front valve 14, so that the front valve 14 seals the pipeline 12 alone. When the pump body is used, the front valve stem can be moved forward to connect with the front valve 14. Specifically, it can be connected with the card groove through elastic buckles.

Specifically, the main driver 8 is built in the casing, and the front driver 7 is connected with the main valve stem. Among them, the main driver 8 and the front driver 7 are both pneumatic.

Specifically, the surface of the secondary condensation adsorption device 5 is coated with activated carbon. The remaining difficult-to-condensable gases after passing through the primary condensation and adsorption device 4, such as hydrogen isotope gas and helium, are condensed and adsorbed by the ultra-low temperature of the secondary condensation and adsorption device 5 and the activated carbon coated on the surface.

Specifically, the front end of the pump body is provided with a front flange, which acts as a neutron radiation shield and reduces the nuclear heating of the pump chamber by neutrons. The main valve seat 9 is provided on the front flange, and the rear end of the pump body is provided with a rear method Lan 6,

The rear flange 6 is provided with the inlet and outlet sub-flange ports of the liquid helium pipeline of the primary condensation adsorption device 4, the inlet and outlet sub-flange ports of the supercritical helium pipeline of the secondary condensation adsorption device 5, and the sub-flange ports of the detection equipment.

In order to further optimize the above solution, the inner surface of the pump body is covered with a heat shield plate 3 . In order to reduce thermal radiation, especially its thermal radiation to low temperature components.

The cryopump with a double valve structure provided by the embodiment of the present invention is a cryogenic pump with a double valve structure applied to CFETR (China Fusion Engineering Experimental Reactor), including a cryopump pump body, a double pneumatic driver, a double valve, a matching The key point of the front valve seat, the front valve axial sealing mechanism, etc. is the double valve design and the front valve matching sealing mechanism, which are used to ensure the continuous operation of the CFETR when a cryogenic pump of the CFETR low temperature pumping system fails. Then, cut off the connection between the cryopump port pipeline and the pipeline of the annular vacuum chamber, and complete the maintenance and replacement operation of the faulty cryopump. It can also replace the main gate valve at the outlet of the divertor, and close the connection pipeline between the annular vacuum chamber and the outside world during the shutdown and maintenance of the device, reduce the huge space occupied by the main gate valve, simplify the internal structure of the tokamak device, and reduce the construction cost of CFETR.

The cryopump with double valve structure provided by the embodiment of the present invention, in actual operation, includes a connecting flange, a hollow pump body sealingly connected with the flange, a double pneumatic drive mechanism sealed through the pump body, a double valve and a front valve head. The matching valve seat and axial ejector rod sealing mechanism, the double pneumatic driving mechanism is nested together through the concentric valve stem, the main driving mechanism corresponds to the main valve 11 of the cryopump, the rear driving mechanism corresponds to the front valve 14, the front valve 14 The valve profile is similar to that of the main valve 11. Under normal working conditions of the pump, the front valve 14 and the main valve 11 are in close contact with each other back to back. As shown in Figure 1, the front valve 14 is also equipped with a set of sealing mechanism. The front valve 14 also has a matching valve seat, which is similar to the valve seat of the main valve of the cryopump and is located on the same axis as the cryopump body.

Specifically, the front driver 7 is installed on the moving sleeve rod of the main driver 8 . When working, the main driver 8 moves the sleeve rod to connect with the main valve 11 through the main valve rod to drive the main valve 11 to move, and the front driver 7 moves the sleeve rod to connect with the front valve 14 through the front valve rod to drive the front valve 14 to move, among which the main valve 14 moves. The rod is a hollow cylinder structure, the front valve rod is a solid cylinder structure, the outer diameter of the front valve rod is smaller than the inner diameter of the main valve rod and is nested inside the main valve rod.

The front valve 14 and the front valve stem are separable, and after the front valve 14 is sealed, the front valve stem can be disconnected from the front valve 14 .

Among them, the front valve 14 adopts an axial sealing mechanism, and is provided with four axial ejector rods 2 placed in the surrounding structure 1 of the cryopump. The end of the axial ejector rod 2 has a radial connecting rod 15 perpendicular to the axial ejector rod 2 , and the end of the radial connecting rod 15 has a cylindrical plug 13 parallel to the axial ejector rod 2 . The axial ejector rod 2 can be rotated. Under normal working conditions, the ejector head 13 at the end of the connecting rod can reach the channel where the section of the front valve 14 is located by rotating.

Among them, there is also a bellows 16 at the connection between the axial ejector rod 2 and the radial connecting rod 15, the axial ejector rod 2 is located inside the bellows tube 16, and one end of the bellows 16 and the axial ejector rod 2 are located in the cryopump enclosing structure 1 The channel outlet is connected to the outlet, and the other end is connected to the radial connecting rod 15.

The cryopump with a double valve structure provided by the embodiment of the present invention aims to solve the problem of insufficient applicability of the existing cryopump, and provides a cryopump with a double valve structure to meet the requirements of continuous operation of CFETR and future fusion reactors. The ability to shut down to replace a faulty cryogenic pump also replaces the gate valve of the divertor outlet pipeline, simplifying the design of the tokamak and reducing costs.

The cryopump with a double valve structure provided by the embodiment of the present invention, in specific implementation, includes a front flange, a rear flange 6, a double pneumatic actuator, a main valve 11, a front valve 14, an 80K louver baffle, a 4.5K cryopanel and The front valve is equipped with an axial sealing mechanism. The front and rear flanges are connected to the pump casing, wherein the rear flange 6 is located at the end of the cryogenic pump, and is provided with a sub-flange for the opening of the cryogenic supply and return pipelines. The rear flange 6 acts as a biological shielding plug for the vacuum chamber port, and the front flange is located at the pump casing. The front part acts as a neutron radiation shield to reduce the nuclear heating of the pump chamber by neutrons. The front flange is provided with a main valve seat.

The 80K annular louver baffle is located inside the pump chamber in a ring structure, and there is an 80K coolant circuit inside the baffle to reduce the heat radiation of the incoming gas to the 4.5K cryopanel and the preliminary condensation of the incoming gas. The 4.5K cryopanel is rectangular, coated with activated carbon on both sides and arranged in a hollow cylinder with a 45° inclination to the radius line where it is located. The helium flow channel is used to cool the surface of the cryopanel to 4.5K, and the activated carbon coated on both sides of the cryopanel is used to adsorb gases such as helium and hydrogen isotopes that are not easy to condense.

The dual pneumatic actuators are both pneumatic actuators. The piston is driven by air to drive the corresponding valve sleeve rod to move. The sleeve rod is fixed on the piston and the piston moves to push the corresponding valve rod. The valve rod is covered by the corresponding sleeve rod to reduce any possible leakage problems. . The front driver 7 is fixed on the sleeve rod of the main driver 8. The movement of the main driver 8 will drive the movement of the front driver 7 to drive the front valve rod inside the sleeve rod of the front driver 7 to move back and forth, and the movement of the piston of the front driver 7 will drive the sleeve rod. Move so that the front stem moves without affecting the movement of the main stem.

The front valve 14 and the front valve stem are separable. When the front valve 14 is resisted by the axial ejector mechanism, the front driver 7 moves, and the front valve 14 is separated from the front valve stem. When the two need to be connected, only the front driver is required. 7. Drive the front valve stem into the docking slot of the front valve 14.

The sealing and locking device is installed in the cryopump enclosure 1, and the cryopump enclosure 1 is welded to the outer Dewar wall. The sealing and locking device includes an axial ejector pin 2, a radial ejector pin 15 and a header 13, and the centerlines of the three are coplanar. One end of the radial ejector pin 15 is fixed with the axial ejector pin 2 facing the inner port, the ejector head 13 is fixed with the other end of the radial ejector pin 15, and the axial ejector pin 2 installed in the cryopump enclosing structure 1 is rotatable. Yes, in this way, the head 13 can move up and down on the surface of the front valve 14 , so as to ensure that the axial movement of the front valve 14 will not be blocked.

The inner surface of the pump casing and the inner surfaces of the front and rear flanges are covered by the heat shield plate 3, and the surface part of the valve drive mechanism located in the pump chamber is also covered by the heat shield plate 3 to reduce the heat radiation to the surface of the 4.5K cryopanel.

The front valve 14 is axially sealed, and the metal sealing method is adopted. The sealing groove is located on the surface of the front valve 14 to ensure that the metal sealing ring can be replaced with the removal and maintenance operation of the cryopump after long-term use.

The cryopump with double valve structure provided by the embodiment of the present invention adopts an arrangement in which an 80K annular louver baffle surrounds a 4.5K cryopanel, which reduces the thermal radiation of the structural components to the surface of the cryopanel, and uses a liquid helium pipeline and an 80K baffle. , 4.5K low temperature baffle and activated carbon's structural design features and mutual cooperation, well realize the condensation of easy-to-condensable gas and difficult-to-condensable gas in the gas to be treated, such as the adsorption of hydrogen isotope gas and helium gas.

The double-valve structure design in the double-valve structure cryopump provided by the embodiment of the present invention can realize the maintenance and replacement operation of the faulty cryopump under the non-stop operation condition. It can also play the function of the gate valve of the main vacuum chamber, and close the main vacuum chamber through the front valve and its supporting sealing mechanism under shutdown conditions. The design of the double-valve cryopump not only meets the traditional pumping speed and capacity requirements, but also meets the requirements of CFETR continuous operating conditions, which greatly improves the safety performance of the entire fusion device.

The cryopump with double valve structure provided by the embodiment of the present invention has reasonable design, simple structure, no electrical equipment, high safety, large air extraction surface and air extraction volume, low engineering difficulty, more suitable for the operation mode of CFETR, and suitable for popularization and application .

The cryopump with double valve structure provided by the embodiment of the present invention is used for vacuum pumping of a CFETR tokamak device and realizes the operation of replacing the faulty pump without stopping when a pump of the pump group fails. When the unit is shut down, the front valve and its sealing mechanism can also replace the main vacuum chamber gate valve to complete the sealing operation of the vacuum chamber.

Specifically, the front flange is fixed on the pump body support structure with nuts, as the neutron shielding component of the cryogenic pump chamber, the front flange is provided with the valve seat of the main valve 11, and the surface of the front flange facing the pump chamber is covered with a layer Heat shield components to reduce their thermal radiation to low temperature components. The rear flange 6 is the first boundary of the vacuum system, and the outer surface directly faces the atmospheric environment. The liquid helium pipeline with 80K louver baffles on it enters and exits the sub-flange, and the supercritical helium pipeline for the 4.5K cryopanel enters and exits the sub-flange. port and detection device sub-flange port.

When the cryopump is working normally, the piston of the front driver 7 stays at zero displacement. At this time, the adjacent surfaces of the front valve 14 and the main valve 11 are attached to each other and maintain this state. The main driver 8 starts to work, and the main valve stem moves forward. The front valve 14 and the main valve 11 move forward together to the designated position, the pump inlet is opened, and the neutral gas at the outlet of the divertor is pumped into the pump through the transport pipe. Part of the gas is condensed on the surface of the baffle, and the remaining difficult-to-condensable gases, such as hydrogen isotope gas and helium, flow into the surface of the 4.5K cryopanel-5 through the baffle, and are condensed and adsorbed under the action of ultra-low temperature and surface-coated activated carbon.

Also, the front valve system of the entire cryopump system is not activated under normal operating conditions. The CFETR cryogenic pumping system consists of multiple cryogenic pumps. When one of the pumps fails, for example, when the 80K coolant pipeline of a pump breaks, the relatively high-pressure coolant release will destroy the vacuum environment of the entire tokamak. At this time, the front driver 7 starts to act, the front valve 14 is separated from the main valve 11, the front valve 14 reaches the front valve seat 10, and the front driver 7 stops running. Further, the sealing and locking device of the front valve 14 installed in the cryopump enclosure 1 starts to act. The axial ejector rod 2 is rotated by 45° under the action of external force to drive the radial ejector rod 15 to make the plug head 13 reach the section where the front valve 14 is located. 14 is sealed on the valve seat. The axial sealing mechanism includes a total of 4 or more such ejector rods to meet the sealing force requirements. When the front valve 14 is dead and sealed, the front driver 7 starts to act, and the front valve stem is retracted and retracted. Because of the separable design of the front valve stem and the front valve 14, only a critical axial tension can make the two separation. After the action of the front driver 7 is completed, the main driver 8 is activated, and the main valve 11 is sealed tightly with the valve seat on the front flange. At this time, the faulty pump can be transferred through remote maintenance measures to realize the replacement operation of the faulty pump under the condition of non-stop reactor.

In addition, the sealing mechanism can also function as a substitute for the lower port annular chamber gate valve when the CFETR is shut down. When the CFETR main unit is shut down for maintenance, the large gate valve at the port of the vacuum vessel will drop down to seal the inside of the annular chamber, preventing the main vacuum chamber from being contaminated. The size of the large gate valve is of the order of meters, and the volume and quality of the entire valve and drive mechanism are very large, and the cost is high. The use of a double-valve cryopump to replace the main gate valve can simplify the device design and save engineering costs while ensuring safety.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

A cryogenic pump with a double valve structure is characterized in that it includes a pump body, a casing, a main valve seat, a main valve stem, a main valve, a main driver, a front valve seat, a front valve stem, a front valve, a front driver, and a sealing lock. compact device, primary condensation adsorption device and secondary condensation adsorption device, wherein,

The main valve seat is located at the front end of the pump body, the main valve is located at the front end of the main valve seat, the front valve is located at the front end of the main valve, and the front valve seat is located at the front end of the front valve. front end,

The primary condensation adsorption device and the secondary condensation adsorption device are built in the pump body, and the inlet and outlet of the supercritical helium pipeline of the primary condensation adsorption device and the secondary condensation adsorption device are connected to the pump rear end of the body,

The sleeve passes through the front and rear ends of the pump body, the main valve stem is set in the sleeve for moving, the front valve stem is moved and set in the main valve stem, and the main valve stem is moved. a valve stem is connected with the main driver, the front valve stem is connected with the front driver,

The main valve is arranged at the end of the main valve stem, the front valve is arranged at the end of the front valve stem,

The front valve seat is arranged on the butting port of the pipeline communicating with the pump body,

Under normal conditions,

When the pump body is opened, the front valve and the main valve are located between the main valve seat and the front valve seat, the pipeline is communicated with the pump body, and the gas from the pipeline enters the pump body. After the pump body is described, the first cooling condensation adsorption is carried out through the first-stage condensation adsorption device, and then the remaining difficult-to-condensable gas is subjected to the second cooling condensation adsorption through the second-stage condensation adsorption device,

When a failure occurs,

The front driver drives the front valve to move to the front valve seat through the front valve rod, and the sealing locking device seals and fixes the front valve on the front valve seat, cutting off the connection with the pipeline. connection,

The main driver drives the main valve to move to the main valve seat to seal the pump body through the main valve rod, so as to replace the faulty pump body.
The cryopump with a double valve structure according to claim 1, wherein the sealing and locking device comprises an axial ejector rod, a radial ejector rod and a plug which are connected in sequence,

Under normal conditions,

The radial ejector rod and the ejector head avoid the movement path of the front valve,

When a failure occurs,

The rotation of the axial ejector rod drives the plug head to the rear end of the front valve through the radial ejector rod, and the axial ejector rod exerts an axial thrust so that the plug head pushes the front valve against the The front valve seat is sealed and fixed.
The cryopump with double valve structure according to claim 2, wherein the sealing and locking devices are plural and are evenly arranged around the front valve seat.
The cryopump with a double valve structure according to claim 2, wherein the outer casing of the axial ejector rod is provided with a bellows.
The cryopump with dual valve structure according to claim 1, wherein the front valve and the front valve stem are detachably connected,

Exceeding a critical axial pulling force disengages the front valve from the front valve stem, and exceeding a critical axial thrust force connects the front valve and the front valve stem.
The cryopump with dual valve structure according to claim 1, wherein the main driver is built in the casing,

The front driver is connected with the main valve stem.
The cryopump with dual valve structure according to claim 6, wherein the main driver and the front driver are both pneumatic.
The cryopump with double valve structure according to claim 1, wherein the surface of the secondary condensation adsorption device is coated with activated carbon.
The cryopump with double valve structure according to claim 1, wherein the front end of the pump body is provided with a front flange, and the main valve seat is provided on the front flange,

The rear end of the pump body is provided with a rear flange,

The rear flange is provided with the inlet and outlet sub-flange ports of the liquid helium pipeline of the primary condensation adsorption device, the inlet and outlet sub-flange ports of the supercritical helium pipeline of the secondary condensation adsorption device, and the sub-flange ports of the detection equipment. .
The cryopump with double valve structure according to claim 1, wherein the inner surface of the pump body is covered with a heat shield.