A ultra-high vacuum solenoid valve and its testing method

Abstract

The present invention provides an ultra-high vacuum solenoid valve and a testing method thereof. The ultra-high vacuum solenoid valve includes a valve body and an iron core assembly. A vacuum port, a volcano-shaped valve port, and a vacuum pumping port are arranged in the valve body. The vacuum pumping port is communicated with the vacuum port through the volcano-shaped valve port. The iron core assembly includes a movable iron core slidably mounted on the upper side of the volcano-shaped valve port and a valve port seal. One end of the movable iron core is recessed to form a seal cavity. An insertion port is arranged at the outer side end of the seal cavity, and an extrusion space is formed by outward expansion of the inner side end thereof. An expansion absorption area is formed by outward expansion at the insertion port. The valve port seal is loaded into the seal cavity from the insertion port by extrusion. The expansion absorption area is used to absorb the deformation amount of the valve port seal, so as to ensure that the sealing surface of the valve port seal is always flat. The ultra-high vacuum solenoid valve and the testing method thereof provided by the present invention overcome the defect that the existing vacuum solenoid valve is not suitable for ultra-high vacuum scenarios due to poor sealing performance.

Description

Technical Field

[0001] The present invention relates to the field of solenoid valves, and particularly to an ultra-high vacuum solenoid valve and a testing method thereof. Background Art

[0002] A vacuum solenoid valve generally includes a vacuum port, a vacuum pumping port, a valve port, a movable iron core and a spring. The vacuum pumping port is connected to a vacuum pump, and the vacuum port is connected to a container. When the electromagnetic coil is energized to generate a magnetic field, the movable iron core moves upward against the spring force to open the valve port, and the vacuum solenoid valve is opened. The vacuum pump is started, and all pipelines are conducted. At this time, the area from the vacuum pump through the vacuum solenoid valve to the container is in a vacuum state. If there is any poor sealing at any place around the vacuum solenoid valve, the vacuum pump will always be in a working state and cannot pump to the required high vacuum state. When the electromagnetic coil is de-energized, the movable iron core moves downward under the action of the spring force to close the valve port. At this time, the vacuum solenoid valve is in a closed state, the vacuum is cut off, the vacuum pump is turned off and the vacuum-breaking valve of the vacuum pump is opened. At this time, the vacuum pumping port end is at atmospheric pressure, and the vacuum port end is at ultra-high vacuum. If the sealing at the valve port is not good at this time, the vacuum port and the container cannot maintain the ultra-high vacuum state.

[0003] Existing vacuum solenoid valves have poor external and / or internal sealing, resulting in the range of the vacuum degree they can use being only limited to 10 -1 pa to 10 -4 pa. With the continuous development of technology and the emergence of new industries, such as photovoltaic, new energy, artificial intelligence, etc., all require higher-performance vacuum solenoid valves for supporting applications. However, the existing vacuum solenoid valves are not suitable for ultra-high vacuum scenarios and need to be improved. Summary of the Invention

[0004] (I) Technical Problems to be Solved

[0005] The problem to be solved by the present invention is to provide an ultra-high vacuum solenoid valve and a testing method thereof to overcome the defect that the existing vacuum solenoid valves are not suitable for ultra-high vacuum scenarios due to poor sealing performance.

[0006] (II) Technical Solutions

[0007] To solve the above technical problems, the present invention provides an ultra-high vacuum solenoid valve, including.

[0008] A valve body, which is internally provided with a vacuum port, a volcanic-shaped valve port and a vacuum pumping port. The vacuum pumping port is communicated with the vacuum port through the volcanic-shaped valve port.

[0009] The iron core assembly includes a movable iron core slidably mounted on the upper side of the volcanic valve port and a valve port seal for opening and closing the volcanic valve port; one end of the movable iron core facing the volcanic valve port is recessed to form a seal cavity, an insertion port is provided at the outer side end of the seal cavity, an extrusion space is formed by outward expansion of its inner side end, and a trumpet-shaped expansion absorption area is formed by outward expansion at the insertion port; the valve port seal is loaded into the seal cavity from the insertion port by extrusion, the extrusion space is used to prevent the valve port seal from being extruded and deformed, and the expansion absorption area is used to absorb the deformation amount of the valve port seal when the valve port seal is pressed against the volcanic valve port, so as to ensure that the sealing surface of the valve port seal is always flat.

[0010] In some embodiments, one end of the valve port seal facing the volcanic valve port is provided with the sealing surface, and a plurality of arc-shaped buffer ribs are arranged at equal intervals in a ring shape at the other end. The buffer ribs protrude outward and abut against the inner wall of the seal cavity, and an elastic area is formed between the sealing surface and the outer end surface of the buffer ribs.

[0011] In some embodiments, an exhaust hole communicating with the extrusion space is provided on the side wall of the movable iron core. The exhaust hole is used to discharge the gas in the seal cavity when installing the valve port seal; a plastic-coated wear-resistant ring is wrapped around the outer circumferential wall of the movable iron core, and an annular energy absorption cavity is provided at the position of the movable iron core close to the seal cavity. The annular energy absorption cavity is located inside the plastic-coated wear-resistant ring.

[0012] In some embodiments, it further includes a magnetic isolation tube assembly located on the upper side of the valve body. The magnetic isolation tube assembly is hermetically connected to the valve body through a compression sealing assembly; the compression sealing assembly includes a spiral sleeve and a sealing ring. The valve body extends towards the magnetic isolation tube assembly and is provided with a threaded post. An annular groove is provided at the end of the threaded post, and the sealing ring is installed in the annular groove; an annular pressing block corresponding to the sealing ring is provided on the magnetic isolation tube assembly. The spiral sleeve is sleeved on the magnetic isolation tube assembly and is threadedly connected to the threaded post, so that the annular pressing block presses the sealing ring.

[0013] In some embodiments, the magnetic isolation tube assembly includes a hollow magnetic isolation tube and a static iron core partially inserted into the magnetic isolation tube. The annular pressing block is arranged on the magnetic isolation tube; a welding shoulder is provided on the static iron core. The welding shoulder abuts against the end of the magnetic isolation tube and is welded and fixed to the magnetic isolation tube; a magnetic isolation tube sealing ring is installed on the outer circumferential wall of the inserted part of the static iron core, and a conical anti-scratch part is formed by shrinking the end of the inserted part of the static iron core.

[0014] In some embodiments, the movable iron core is slidably mounted inside the magnetic isolation tube. One end of the static iron core facing the movable iron core has an attracting surface, and an energy-absorbing groove is provided on the attracting surface, and an anti-collision piece is mounted outside the energy-absorbing groove.

[0015] In some embodiments, an iron core spring is mounted between the movable iron core and the magnetic isolation tube assembly. The iron core spring always makes the movable iron core tend to move towards the volcanic-shaped valve port. A circular flange is provided at the lower end of the movable iron core, and a spring limiting groove is provided on the magnetic isolation tube assembly. One end of the iron core spring abuts against the circular flange, and the other end abuts against the spring limiting groove.

[0016] In some embodiments, an electromagnetic coil is sleeved outside the magnetic isolation tube assembly, and the electromagnetic coil is fixedly connected to the magnetic isolation tube assembly through a fastening nut.

[0017] In some embodiments, the vacuum port and the vacuum pumping port are arranged coaxially, the volcanic-shaped valve port, the iron core assembly and the magnetic isolation tube assembly are arranged coaxially, the axis of the vacuum port is perpendicular to the axis of the volcanic-shaped valve port, and the valve port seal is in a T shape.

[0018] The present invention also provides a testing method for a ultra-high vacuum solenoid valve, which is implemented based on the ultra-high vacuum solenoid valve and includes the following steps.

[0019] A01, external leakage test: Turn on the ultra-high vacuum solenoid valve by electrifying it. Connect its vacuum pumping port to a vacuum pump and its vacuum port to a container. The space between the vacuum pump, the ultra-high vacuum solenoid valve and the container is in an ultra-high vacuum state. Then, by means of the helium leak detection method of a mass spectrometer, place the ultra-high vacuum solenoid valve into the sealed cavity of the mass spectrometer and fill helium gas into the sealed cavity. Calculate the leakage rate of the tested part and judge whether it is qualified. If it is qualified, proceed to step A02, otherwise it is a non-conforming product.

[0020] A02, internal leakage test: Turn off and close the ultra-high vacuum solenoid valve. Connect its vacuum pumping port to a vacuum pump, and turn on the vacuum pump. The space between the vacuum pump and the ultra-high vacuum solenoid valve is in an ultra-high vacuum state. Then, by means of the helium leak detection method of a mass spectrometer, connect the vacuum port of the ultra-high vacuum solenoid valve to the helium gas inlet of the mass spectrometer and fill helium gas. Calculate the leakage rate of the tested part and judge whether it is qualified. If it is qualified, it is a qualified product, otherwise it is a non-conforming product.

[0021] The helium leak detection method includes the following steps.

[0022] B01, calculate the effective minimum detectable leakage rate Q of the system emin ; Input the standard leakage rate Q of the tested part into the mass spectrometer 标 , and then obtain I in the mass spectrometer n, the numerical values of I1, I0, Q0, and γ parameters, and calculate Q through the following formula emin。

[0023] ;

[0024] wherein, I n —background noise value, Pa·m 3 / s; I1—calibration leak orifice response value, Pa·m 3 / s; I0—system background value, Pa·m 3 / s; Q0—calibration leak orifice leak rate, Pa·m 3 / s; γ—helium concentration, ppm.

[0025] Finally, judge whether Q emin is less than one-tenth of Q 标 . If so, enter step B02; otherwise, debug the mass spectrometer.

[0026] B02. Apply nitrogen; close the calibration valve of the mass spectrometer, record the time t experienced when the reading of the mass spectrometer drops from I1 to I0 + 0.37(I1 - I0). t is the response time of the leak detection system; then, after the system background returns to I0, apply helium with a concentration of γ to the part to be inspected, and the helium application time is not less than 3t, and record the response value I of the part to be inspected 2。

[0027] B03. Calculate the leak rate Q of the part to be inspected; substitute the I2, I1, I0, Q0, and γ parameters into the following formula to calculate Q.

[0028] ;

[0029] wherein, I2—response value of the part to be inspected, Pa·m 3 / s.

[0030] Finally, judge whether Q is less than Q 标 . If so, it is qualified; otherwise, it is unqualified.

[0031] (III) Beneficial effects.

[0032] A ultra-high vacuum solenoid valve and its testing method provided by the present invention have the following advantages compared with the prior art.

[0033] 1) After the valve port seal is press-fitted into the seal cavity, since there is an extrusion space (clearance fit) in the seal cavity, the valve port seal will not be deformed due to extrusion and affect the seal with the volcanic valve port; an expansion absorption area is provided. When the valve port seal and the volcanic valve port are extruded under the action of the iron core spring, the valve port seal will be deformed. At this time, the expansion absorption area can absorb the deformation amount, so that the sealing surface always remains flat and the internal sealing effect is excellent.

[0034] 2) A sealing ring is provided between the magnetic isolation tube assembly and the valve body. When the spiral sleeve is rotated, the annular pressing block can tightly press the sealing ring smoothly without damaging the sealing ring, ensuring reliable and stable sealing. This breaks the previous design of rotating and pressing, and the sealing ring will not be twisted, flipped, or deformed due to rotation, effectively improving the external sealing effect. To ensure absolute sealing, a magnetic isolation tube sealing ring is provided at the middle position of the static iron core, adding an extra guarantee for sealing and ensuring the reliability of external sealing.

[0035] 3) The design of adding buffer ribs to the valve port seal increases the height of the elastic zone, making the overall elastic space larger. During the assembly extrusion process, it can not only ensure strong elastic force but also keep the sealing surface flat all the time. At the same time, the air at the end of the valve port seal will flow out of the exhaust hole more smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0037] Figure 1 It is a schematic structural diagram of a super-vacuum solenoid valve according to the present invention.

[0038] Figure 2 It is a schematic structural diagram of an iron core assembly of a super-vacuum solenoid valve according to the present invention.

[0039] Figure 3 It is a schematic structural diagram of a movable iron core of a super-vacuum solenoid valve according to the present invention.

[0040] Figure 4 It is a schematic structural diagram of the connection between a movable iron core and a valve port seal of a super-vacuum solenoid valve according to the present invention.

[0041] Figure 5 It is a schematic structural diagram of a valve port seal of a super-vacuum solenoid valve closing a volcanic valve port according to the present invention.

[0042] Figure 6 It is a schematic structural diagram of a valve port seal of a super-vacuum solenoid valve according to the present invention.

[0043] Figure 7 It is a schematic structural diagram of a valve port seal of a super-vacuum solenoid valve from a top view according to the present invention.

[0044] Figure 8 It is a schematic structural diagram of a pressing and sealing assembly of a super-vacuum solenoid valve according to the present invention.

[0045] Figure 9 This is a schematic structural diagram of a super-vacuum solenoid valve magnetic isolation tube assembly of the present invention.

[0046] The corresponding component names for the reference numerals in the figure are: 1, valve body; 101, vacuum port; 102, volcanic valve port; 103, vacuum pumping port; 104, threaded post; 105, annular groove; 2, iron core assembly; 21, movable iron core; 22, valve port seal; 23, plastic-coated wear-resistant ring; 211, seal cavity; 212, placement port; 213, extrusion space; 214, expansion absorption area; 215, exhaust hole; 216, annular energy absorption cavity; 217, annular flange; 221, sealing surface; 222, buffer rib; 223, elastic area; 3, fastening nut; 4, magnetic isolation tube assembly; 41, magnetic isolation tube; 42, static iron core; 43, magnetic isolation tube sealing ring; 44, anti-collision piece; 401, annular pressing block; 402, spring limit groove; 421, welding shoulder; 422, conical anti-scratch part; 423, energy absorption groove; 5, pressing and sealing assembly; 51, spiral sleeve; 52, sealing ring; 6, iron core spring; 7, electromagnetic coil. Specific embodiments

[0047] The present application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] The following illustrates the implementation manners of the present application through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0049] It should be noted that the following describes various aspects of embodiments within the scope of the appended claims. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement a device and / or practice a method. Additionally, this device and / or method can be implemented using other structures and / or functionality in addition to one or more of the aspects set forth herein.

[0050] It should also be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of this application. Only the components related to this application are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in its actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0051] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that these examples can be practiced without these specific details.

[0052] The following describes the technical solutions provided by each embodiment of this application in conjunction with the accompanying drawings.

[0053] Refer to Figures 1 to 9 , the present invention provides a ultra-high vacuum solenoid valve, which includes a valve body 1, an iron core assembly 2, a magnetic isolation tube assembly 4, a pressing and sealing assembly 5, an iron core spring 6, and an electromagnetic coil 7.

[0054] Refer to Figure 1 and Figure 2 , a vacuum port 101, a volcanic-shaped valve port 102, and a vacuum pumping port 103 are provided in the valve body 1. The vacuum pumping port 103 is communicated with the vacuum port 101 through the volcanic-shaped valve port 102. Among them, the vacuum port 101 and the vacuum pumping port 103 are respectively located on both sides of the valve body 1, and the vacuum port 101 and the vacuum pumping port 103 are arranged coaxially. The axis of the vacuum port 101 is perpendicular to the axis of the volcanic-shaped valve port 102. The iron core assembly 2 includes a movable iron core 21 slidably installed above the volcanic-shaped valve port 102 and a valve port seal 22 for opening and closing the volcanic-shaped valve port 102. The valve port seal 22 is located directly above the volcanic-shaped valve port 102, and the valve port seal 22 can be driven by the movable iron core 21 to open or close the volcanic-shaped valve port 102.

[0055] Refer to Figures 2 to 5The end of the movable iron core 21 facing the volcano-shaped valve port 102 is concave to form a sealing cavity 211, wherein the valve port sealing member 22 is T-shaped, and the shape of the sealing cavity 211 is similar to the outer contour of the valve port sealing member 22. An insertion port 212 is provided at the outer end of the sealing cavity 211, and an extrusion space 213 is formed by expanding the inner end of the sealing cavity 211, and the extrusion space 213 is connected to the sealing cavity 211. A trumpet-shaped expansion absorption area 214 is formed at the insertion port 212, and the expansion absorption area 214 is connected to the insertion port 212. The valve seal 22 is loaded into the seal cavity 211 from the insertion port 212 by extrusion. The extrusion space 213 is set so that after the valve seal 22 is loaded, there is a certain gap between the outer wall of the end of the valve seal 22 away from the sealing surface 221 and the inner wall of the seal cavity 211. On the one hand, the gap can prevent the valve seal 22 from being squeezed and deformed during loading. On the other hand, when the sealing surface 221 is pressed against the volcano-shaped valve port 102, the deformation of the valve seal 22 can be absorbed to ensure the flatness of the sealing surface 221, thereby improving the internal sealing performance. The expansion absorption area 214 is used to absorb the deformation of the valve seal 22 when the valve seal 22 is pressed against the volcano-shaped valve port 102, thereby ensuring that the sealing surface 221 of the valve seal 22 is always flat.

[0056] In the prior art, some vacuum solenoid valve manufacturers, in order to achieve a higher vacuum degree, use the method of increasing the core spring force to make the sealing surface and the valve port contact more closely (internal seal) to improve the sealing requirements, thereby achieving a better leakage value; but this often comes at a higher price. In order to overcome the spring force, the coil volume is made larger and the power is made higher, which not only increases the cost, but also fails to meet the leakage value requirements during actual application. The increased spring force has no effect at all under ultra-vacuum conditions.

[0057] Internal sealing is very important. In the present invention, after the valve port seal 22 and the seal cavity 211 are squeezed and installed, since the seal cavity 211 has an extrusion space (clearance fit), the valve port seal 22 will not be deformed due to extrusion and affect the seal with the volcano-shaped valve port 102. An expansion absorption area 214 is provided. When the valve port seal 22 and the volcano-shaped valve port 102 are squeezed under the action of the iron core spring 6, the valve port seal 22 will be deformed. At this time, the expansion absorption area 214 can absorb the deformation, so that the sealing surface 221 is always kept flat, and the internal sealing effect is excellent.

[0058] In some embodiments, Figures 4 to 7As shown in the figure, one end of the valve port seal 22 facing the volcanic valve port 102 is provided with a sealing surface 221, and the sealing surface 221 corresponds to the expansion absorption area 214. At the other end of the valve port seal 22, a plurality of arc-shaped buffer ribs 222 are arranged at equal intervals in a ring shape. In this embodiment, there are four buffer ribs 222. The buffer ribs 222 protrude outward and abut against the inner wall of the seal cavity 211, and an elastic area 223 is formed between the outer end surfaces of the sealing surface 221 and the buffer ribs 222. In this structure, with the design of adding the buffer ribs 222 to the valve port seal 22, the height of the elastic area 223 is increased, making the overall elastic space larger. During the assembly extrusion process, it can not only ensure strong elastic force, but also keep the sealing surface 221 flat all the time. At the same time, the air at the end of the valve port seal 22 will flow out more smoothly from the exhaust hole 215.

[0059] In some embodiments, as Figures 4 to 7 shown, the side wall of the movable iron core 21 is provided with an exhaust hole 215 communicating with the extrusion space 213. The exhaust hole 215 is used to discharge the gas in the seal cavity 211 when installing the valve port seal 22; by setting the exhaust hole 215, the gas in the seal cavity 211 can be discharged when extruding and installing the valve port seal 22, so that the valve port seal 22 can fit smoothly in the seal cavity 211. A plastic-coated wear-resistant ring 23 is wrapped around the outer circumferential wall of the movable iron core 21. The movable iron core 21 is provided with an annular energy absorption cavity 216 at a position close to the seal cavity 211, and the annular energy absorption cavity 216 is located inside the plastic-coated wear-resistant ring 23; the outer wall of the movable iron core 21 is wrapped with the plastic-coated wear-resistant ring 23, making the up and down movement of the movable iron core 21 smooth and reducing the friction coefficient; to ensure that the plastic-coated wear-resistant ring 23 can completely wrap the movable iron core, an annular energy absorption cavity is provided on the surface to make the roundness and concentricity of its wrapping better.

[0060] In some embodiments, as Figure 1 and Figure 8 shown, the magnetic isolation tube assembly 4 is located on the upper side of the valve body 1, and the magnetic isolation tube assembly 4 is hermetically connected to the valve body 1 through a compression sealing assembly 5. The compression sealing assembly 5 includes a spiral sleeve 51 and a sealing ring 52. The valve body 1 extends towards the magnetic isolation tube assembly 4 and is provided with a threaded post 104. An annular groove 105 is provided at the end of the threaded post 104, and the sealing ring 52 is installed in the annular groove 105; an annular pressing block 401 corresponding to the sealing ring 52 is provided on the magnetic isolation tube assembly 4, and the annular pressing block 401 abuts against the sealing ring 52. The spiral sleeve 51 is sleeved on the magnetic isolation tube assembly 4 and is threadedly connected to the threaded post 104, so that the annular pressing block 401 presses the sealing ring 52.

[0061] In an ultra-high vacuum environment, in addition to the extremely high internal sealing requirements, the external sealing is also one of the key points. The external sealing mainly lies in the sealing between the magnetic isolation tube assembly 4 and the valve body 1 and the sealing of the magnetic isolation tube assembly 4 itself. In this structure, a sealing ring is provided between the magnetic isolation tube assembly and the valve body. When the rotary spiral sleeve 51 is rotated, the annular pressing block 401 can stably press the sealing ring 52 without damaging the sealing ring, and the sealing is reliable and stable. It breaks the previous design of rotating and pressing, and the sealing ring will not be twisted, flipped and deformed due to rotation, effectively improving the sealing effect.

[0062] In some embodiments, such as Figure 1 and Figure 9 shown, the magnetic isolation tube assembly 4 includes a hollow magnetic isolation tube 41 and a static iron core 42 partially inserted into the magnetic isolation tube 41. The annular pressing block 401 is arranged on the magnetic isolation tube 41; a welding shoulder 421 is arranged on the static iron core 42, and the welding shoulder 421 abuts against the end of the magnetic isolation tube 41 and is fixedly welded to the magnetic isolation tube 41; a magnetic isolation tube sealing ring 43 is installed on the outer circumferential wall of the inserted part of the static iron core 42, and a conical anti-scratch part 422 is formed by shrinking the end of the inserted part of the static iron core 42. The moving iron core 21 is slidably installed in the magnetic isolation tube 41. One end of the static iron core 42 facing the moving iron core 21 has an attracting surface, and an energy-absorbing groove 423 is arranged on the attracting surface. An anti-collision piece 44 is installed outside the energy-absorbing groove 423.

[0063] Since tiny welding pores will be formed after material welding, under ultra-high vacuum conditions, to ensure absolute sealing, a magnetic isolation tube sealing ring 43 is provided at the middle position of the static iron core 42, adding an extra guarantee for sealing and ensuring the reliability of external sealing. Since the static iron core 42 is provided with a conical anti-scratch part 422, when the static iron core 42 and the magnetic isolation tube 41 are in interference fit, under the action of the conical anti-scratch part 422, metals will not be forcibly scratched to produce metal foam and iron filings, which will affect the internal cleanliness of the solenoid valve. In addition, an anti-collision piece is arranged on the attracting surface of the static iron core. Under the action of the energy-absorbing groove, even if there are continuous impacts, the attracting surface can be ensured to be flat without impact powder generation.

[0064] In some embodiments, such as Figure 1 and Figure 5 shown, a core spring 6 is installed between the moving iron core 21 and the magnetic isolation tube assembly 4. The core spring 6 always makes the moving iron core 21 tend to move towards the volcanic valve port 102; an annular flange 217 is arranged at the lower end of the moving iron core 21, and a spring limit groove 402 is arranged on the magnetic isolation tube assembly 4; one end of the core spring 6 abuts against the annular flange 217, and the other end abuts against the spring limit groove 402. An electromagnetic coil 7 is sleeved on the magnetic isolation tube assembly 4, and the electromagnetic coil 7 is fixedly connected to the magnetic isolation tube assembly 4 through a fastening nut 3.

[0065] The present invention also provides a test method for a ultra-high vacuum solenoid valve, which is implemented based on the above-mentioned ultra-high vacuum solenoid valve and includes the following steps.

[0066] A01. External leakage test: Energize and open the ultra-high vacuum solenoid valve. Connect its vacuum extraction port 103 to a vacuum pump and its vacuum port 101 to a container. The space among the vacuum pump, the ultra-high vacuum solenoid valve and the container is in an ultra-high vacuum state. Then, by means of the helium leak detection method of a mass spectrometer, place the ultra-high vacuum solenoid valve into the sealed cavity of the mass spectrometer and fill helium gas into the sealed cavity. Calculate the leak rate of the part to be tested and determine whether it is qualified. If it is qualified, proceed to step A02; otherwise, it is a defective product.

[0067] A02. Internal leakage test: Cut off the power supply and close the ultra-high vacuum solenoid valve. Connect its vacuum extraction port 103 to a vacuum pump and turn on the vacuum pump. The space between the vacuum pump and the ultra-high vacuum solenoid valve is in an ultra-high vacuum state. Then, by means of the helium leak detection method of a mass spectrometer, connect the vacuum port 101 of the ultra-high vacuum solenoid valve to the helium gas inlet of the mass spectrometer and fill helium gas. Calculate the leak rate of the part to be tested and determine whether it is qualified. If it is qualified, it is a qualified product; otherwise, it is a defective product.

[0068] The helium leak detection method includes the following steps.

[0069] B01. Calculate the effective minimum detectable leak rate Q of the system emin ; Input the standard leak rate Q of the part to be tested into the mass spectrometer 标 , and then obtain the values of I n , I1, I0, Q0 and γ parameters in the mass spectrometer, and calculate Q through the following formula emin。

[0070] ;

[0071] Wherein, I n —background noise value, Pa·m 3 / s; I1—calibration leak hole response value, Pa·m 3 / s; I0—system background value, Pa·m 3 / s; Q0—calibration leak hole leak rate, Pa·m 3 / s; γ—helium concentration, ppm.

[0072] Finally, judge whether Q emin is less than one-tenth of Q 标 . If so, proceed to step B02; otherwise, debug the mass spectrometer.

[0073] B02. Apply nitrogen gas; close the calibration valve of the mass spectrometer, and record the time t it takes for the reading of the mass spectrometer to drop from I1 to I0 + 0.37(I1 - I0). t is the response time of the leak detection system. Then, after the system background returns to I0, apply helium gas with a concentration of γ to the part to be inspected for a time not less than 3t, and record the response value I of the part to be inspected. 2。

[0074] B03. Calculate the leak rate Q of the part to be inspected; substitute the parameters I2, I1, I0, Q0, and γ into the following formula to calculate Q.

[0075] ;

[0076] where, I2—the response value of the part to be inspected, Pa·m 3 / s.

[0077] Finally, determine whether Q is less than Q 标 , if so, it is qualified, otherwise it is unqualified.

[0078] The existing vacuum solenoid valves only test internal leakage and only use air during the test, so the test results are not very realistic. Under the requirements of ultra-high vacuum, when the vacuum degree reaches 10 -6 pa to 10 -7 pa, it is already in the ultimate vacuum, and simple detection methods can no longer meet the detection of ultra-high vacuum solenoid valves. The present invention adopts the helium detection method of a mass spectrometer to test both external and internal leakage; when detecting external leakage, place the solenoid valve in a sealed cavity and then inject helium gas. At this time, the outside of the solenoid valve is completely surrounded by helium gas. When the inside of the solenoid valve is in an ultra-high vacuum environment, the detection method of the present invention can conduct a comprehensive detection on any part of the solenoid valve, and the detection results are true and effective. When detecting internal leakage, the solenoid valve is in the closed state, mainly detecting the seal between the valve port seal and the volcanic valve port, and using the method of injecting helium gas to detect the change in vacuum degree, and the detection results are true and effective.

[0079] For the same or similar parts among the various embodiments in this specification, reference can be made to each other. Each embodiment focuses on the differences from other embodiments.

[0080] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A ultra-high vacuum solenoid valve, characterized in that, Comprising: A valve body (1) having a vacuum port (101), a volcano-shaped valve port (102), and a vacuum pumping port (103) disposed therein. The vacuum pumping port (103) is communicated with the vacuum port (101) through the volcano-shaped valve port (102). An iron core assembly (2) including a movable iron core (21) slidably mounted on the upper side of the volcano-shaped valve port (102) and a valve port seal (22) for opening and closing the volcano-shaped valve port (102). One end of the movable iron core (21) facing the volcano-shaped valve port (102) is recessed to form a seal cavity (211). An insertion port (212) is provided at the outer end of the seal cavity (211), and an extrusion space (213) is formed by outward expansion at its inner end. An expanded absorption area (214) in the shape of a horn is formed by outward expansion at the insertion port (212). The valve port seal (22) is loaded into the seal cavity (211) from the insertion port (212) by extrusion. The extrusion space (213) is used to prevent the valve port seal (22) from being extruded and deformed. The expanded absorption area (214) is used to absorb the deformation amount of the valve port seal (22) when the valve port seal (22) is pressed against the volcano-shaped valve port (102), so as to ensure that the sealing surface (221) of the valve port seal (22) is always flat. One end of the valve port seal (22) facing the volcano-shaped valve port (102) is provided with the sealing surface (221), and a plurality of arc-shaped buffer ribs (222) are annularly and equidistantly arranged at the other end thereof. The buffer ribs (222) protrude outward and abut against the inner wall of the seal cavity (211). An elastic area (223) is formed between the outer end surfaces of the sealing surface (221) and the buffer ribs (222). An exhaust hole (215) communicating with the extrusion space (213) is provided on the side wall of the movable iron core (21). The exhaust hole (215) is used to discharge the gas in the seal cavity (211) when installing the valve port seal (22). A plastic-coated wear-resistant ring (23) is wrapped around the outer circumferential wall of the movable iron core (21). An annular energy absorption cavity (216) is provided at a position of the movable iron core (21) close to the seal cavity (211). The annular energy absorption cavity (216) is located inside the plastic-coated wear-resistant ring (23). It further includes a magnetic isolation tube assembly (4) located on the upper side of the valve body (1), and the magnetic isolation tube assembly (4) is hermetically connected to the valve body (1) through a compression sealing assembly (5); the compression sealing assembly (5) includes a spiral sleeve (51) and a sealing ring (52), the valve body (1) extends towards the magnetic isolation tube assembly (4) and is provided with a threaded post (104), an annular groove (105) is arranged at the end of the threaded post (104), and the sealing ring (52) is installed in the annular groove (105); an annular pressing block (401) corresponding to the sealing ring (52) is arranged on the magnetic isolation tube assembly (4), the spiral sleeve (51) is sleeved on the magnetic isolation tube assembly (4) and is threadedly connected to the threaded post (104), so that the annular pressing block (401) presses the sealing ring (52).

2. The ultra-high vacuum solenoid valve according to claim 1, characterized in that: The magnetic isolation tube assembly (4) includes a hollow magnetic isolation tube (41) and a static iron core (42) partially inserted into the magnetic isolation tube (41), and the annular pressing block (401) is arranged on the magnetic isolation tube (41); a welding shoulder (421) is arranged on the static iron core (42), the welding shoulder (421) abuts against the end of the magnetic isolation tube (41) and is fixedly welded to the magnetic isolation tube (41); a magnetic isolation tube sealing ring (43) is installed on the outer circumferential wall of the inserted part of the static iron core (42), and the end of the inserted part of the static iron core (42) is shrunk to form a conical anti-scratch part (422).

3. The ultra-high vacuum solenoid valve according to claim 2, characterized in that: The movable iron core (21) is slidably installed in the magnetic isolation tube (41), one end of the static iron core (42) facing the movable iron core (21) has a suction surface, an energy absorption groove (423) is arranged on the suction surface, and an anti-collision sheet (44) is installed outside the energy absorption groove (423).

4. The ultra-high vacuum solenoid valve according to claim 1, wherein: An iron core spring (6) is installed between the movable iron core (21) and the magnetic isolation tube assembly (4), and the iron core spring (6) always makes the movable iron core (21) tend to move towards the volcanic valve port (102); an annular flange (217) is arranged at the lower end of the movable iron core (21), and a spring limit groove (402) is arranged on the magnetic isolation tube assembly (4); one end of the iron core spring (6) abuts against the annular flange (217), and the other end abuts against the spring limit groove (402).

5. The ultra-high vacuum solenoid valve according to claim 1, characterized in that: An electromagnetic coil (7) is sleeved on the magnetic isolation tube assembly (4), and the electromagnetic coil (7) is fixedly connected to the magnetic isolation tube assembly (4) through a fastening nut (3).

6. The ultra-high vacuum solenoid valve according to claim 1, characterized in that: The vacuum port (101) and the vacuum pumping port (103) are arranged coaxially, the volcanic valve port (102), the iron core assembly (2) and the magnetic isolation tube assembly (4) are arranged coaxially, the axis of the vacuum port (101) is perpendicular to the axis of the volcanic valve port (102), and the valve port seal (22) is in a T shape.

7. A testing method for an ultra-high vacuum solenoid valve, implemented based on the ultra-high vacuum solenoid valve according to any one of claims 1 to 6, characterized in that, It includes the following steps: A01. External leakage test: Energize and open the ultra-high vacuum solenoid valve. Connect its vacuum pumping port (103) to a vacuum pump and its vacuum port (101) to a container. The space between the vacuum pump, the ultra-high vacuum solenoid valve and the container is in an ultra-high vacuum state. Then, by means of the helium leak detection method of a mass spectrometer, place the ultra-high vacuum solenoid valve in the sealed chamber of the mass spectrometer and fill the sealed chamber with helium gas. Calculate the leak rate of the part to be inspected and determine whether it is qualified. If it is qualified, proceed to step A02; otherwise, it is a defective product. A02. Internal leakage test: De-energize and close the ultra-high vacuum solenoid valve. Connect its vacuum pumping port (103) to a vacuum pump. Turn on the vacuum pump, and the space between the vacuum pump and the ultra-high vacuum solenoid valve is in an ultra-high vacuum state. Then, by means of the helium leak detection method of a mass spectrometer, connect the vacuum port (101) of the ultra-high vacuum solenoid valve to the helium gas inlet of the mass spectrometer and fill it with helium gas. Calculate the leak rate of the part to be inspected and determine whether it is qualified. If it is qualified, it is a qualified product; otherwise, it is a defective product. The helium leak detection method includes the following steps: B01, calculating the effective minimum detectable leak rate Q of the system emin ; Input the standard leak rate Q of the part to be tested into the mass spectrometer 标 , and then obtain the values of I n , I1, I0, Q0 and γ parameters in the mass spectrometer, and calculate Q through the following formula emin ; ； Wherein, I n — background noise value, Pa·m 3 / s; I1 — calibration leak hole response value, Pa·m 3 / s; I0 — system background value, Pa·m 3 / s; Q0 — calibration leak hole leakage rate, Pa·m 3 / s; γ — helium concentration, ppm; Finally, judge Q emin to see if it is less than 标 one tenth of it. If so, go to step B02; otherwise, debug the mass spectrometer. B02. Apply nitrogen: Close the calibration valve of the mass spectrometer. Record the time t it takes for the reading of the mass spectrometer to drop from I1 to I0 + 0.37(I1 - I0). t is the response time of the leak detection system. Then, after the system background returns to I0, apply helium gas with a concentration of γ to the part to be inspected for a time not less than 3t, and record the response value I2 of the part to be inspected. B03. Calculate the leak rate Q of the part to be inspected: Substitute the parameters I2, I1, I0, Q0, and γ into the following formula to calculate Q. ； wherein, I2—the reaction value of the component under test, Pa·m 3 / s; Finally, determine whether Q is less than Q 标 . If so, it is qualified; otherwise, it is a non-conforming product.

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