Vacuum standard leak hole

Abstract

The invention relates to the technical field of vacuum standard leak holes, in particular to a vacuum standard leak hole which comprises an upper connecting piece, a lower connecting piece, a blocking piece, an upper indium ring, a lower indium ring and an indium block. Helium or other leakage indicating gas flowing in from the gas inlet flows out from the gas outlet after sequentially passing through the inner wall of the upper indium ring, the interior of the upper indium ring, the bottom face of the upper indium ring, the top end face of the indium block, the bottom end face of the indium block, the top face of the lower indium ring, the interior of the lower indium ring and the inner wall of the lower indium ring. On the whole, the upper indium ring, the indium block and the lower indium ring are used for constructing the trace permeation channel of the leakage indicating gas, compared with a mode that the leakage indicating gas directly permeates along the vertical direction of the plane where the permeable membrane is located, the trace permeation path is greatly prolonged, and meanwhile, part of the leakage indicating gas flowing into the permeation channel can be diffused into the atmosphere to be consumed.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum standard leak holes, and in particular to a vacuum standard leak hole. Background Art

[0002] Vacuum leak detection technology is one of the important branches of vacuum technology. For vacuum containers or other sealed containers, vacuum leak detection technology is mainly used to determine whether there is a leak, determine the specific location of the leak, and measure the amount of the leak. Common leak detection methods for vacuum leak detection technology include pressure change leak detection method, bubble leak detection method, mass spectrometry leak detection method, etc. Among them, mass spectrometry leak detection method has become one of the most widely used leak detection methods due to its advantages such as high leak detection sensitivity.

[0003] The mass spectrometry leak detection method uses a mass spectrometer to convert the flow of the leak-indicating gas leaking through the vacuum standard leak hole into the ion current of the mass spectrometer, and detects the leak rate by measuring the size of the ion flow signal. The vacuum standard leak hole is an indispensable measuring instrument in the mass spectrometry leak detection method. The mass spectrometry leak detection system is calibrated using the vacuum standard leak hole to realize the conversion between the ion flow signal and the leak rate of the leak-indicating gas.

[0004] Vacuum standard leaks can be divided into two categories: permeation type vacuum standard leaks and channel type vacuum standard leaks. The leak element of the permeation type vacuum standard leak is made based on the principle that some materials are permeable to gases, such as quartz helium-infiltrated standard leaks. The leak element of the channel type vacuum standard leak is a physically throttled gas channel, such as a capillary standard leak and a metal flattened standard leak.

[0005] Since the lower limit of the leakage rate of the permeation type vacuum standard leak is significantly lower than that of the channel type vacuum standard leak, the mass spectrometry leak detection method mostly uses the permeation type vacuum standard leak. The quartz helium-infiltrated standard leak is the most widely used permeation type vacuum standard leak. When the quartz helium-infiltrated standard leak is used as a specific vacuum standard leak, the leak-indicating gas passes through the quartz film in the vertical direction of the surface where the quartz helium-infiltrated standard leak is located. According to the leakage rate calculation formula of the quartz helium-infiltrated standard leak, when the material permeability coefficient K and the upstream and downstream pressure difference p remain unchanged, the leakage rate Q is proportional to the area A of the quartz film and inversely proportional to the thickness D of the quartz film. In order to reduce the lower limit of the permeation type vacuum standard leak, it is necessary to reduce the area A of the quartz film or increase the thickness D of the quartz film. At present, the lower limit of the leakage rate of the quartz helium-infiltrated standard leak has reached its limit. With the continuous improvement of leak detection technology, it is necessary to further reduce the lower limit of the leakage rate of the vacuum standard leak. If the existing leakage rate is to be reduced by several orders of magnitude, the area A of the quartz film needs to be reduced by several orders of magnitude, or the thickness D of the quartz film needs to be increased by several orders of magnitude. However, it is not realistic to make the permeation area of ​​the quartz film very small or to make the thickness of the quartz film very large in actual production.

[0006] Therefore, how to further reduce the lower limit of the leakage rate of the vacuum standard leak to meet higher leak detection requirements has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0007] The invention provides a vacuum standard leak hole, which is used to solve the problem of how to further reduce the lower limit of the leakage rate of the vacuum standard leak hole.

[0008] The present invention provides a vacuum standard leak, comprising:

[0009] The upper connecting member is formed with an air inlet and an upper receiving groove is formed on the bottom surface;

[0010] The lower connecting member is formed with an air outlet; the air outlet is arranged opposite to the air inlet; the top surface of the lower connecting member is formed with a lower receiving groove; the lower connecting member is connected to the upper connecting member;

[0011] A baffle is installed between the upper connecting member and the lower connecting member to isolate the air inlet from the air outlet; a flow-through hole is formed on the baffle;

[0012] An upper indium ring is embedded in the upper receiving groove, and an upper indium ring is formed at the bottom end;

[0013] A lower indium ring is embedded in the lower receiving groove, and a lower indium ring is formed on the top;

[0014] An indium block is embedded in the flow hole;

[0015] The helium gas flowing in from the air inlet passes through the inner wall of the upper indium ring, the interior of the upper indium ring, the bottom surface of the upper indium ring, the indium block, the top surface of the lower indium ring, the interior of the lower indium ring and the inner wall of the lower indium ring in sequence, and then flows out from the air outlet.

[0016] In some embodiments, a protrusion is formed at the bottom end of the upper connecting member; an upper receiving groove is formed at the bottom end of the protrusion;

[0017] The top end of the lower connecting piece is formed with a groove matched with the raised portion; the bottom end of the groove is formed with a lower accommodating groove; and a blocking piece is installed in the groove.

[0018] In some embodiments, the upper connecting member and the lower connecting member are flanges.

[0019] In some of the embodiments, the upper connecting member and the lower connecting member are detachably connected.

[0020] In some of the embodiments, there are four flow-through holes, which are evenly distributed along the circumference of the baffle; accordingly, there are four indium blocks, which are embedded in the flow-through holes in a one-to-one correspondence with the four flow-through holes.

[0021] In some embodiments, the baffle is circular, has a diameter of 20 mm, and a thickness of 0.5 mm;

[0022] The diameter of each flow-through hole is 1 mm, and the distance between the center of the hole and the center of the baffle is 4.5 mm;

[0023] The cross-section of each indium block has a diameter of 1 mm and an axial length of 0.5 mm;

[0024] The inner diameter of the upper indium ring is 4 mm and the outer diameter is 14 mm;

[0025] The inner diameter of the lower indium ring is 4 mm and the outer diameter is 14 mm.

[0026] In some embodiments, the upper connecting member, the lower connecting member and the blocking piece are made of stainless steel.

[0027] The beneficial effects of the present invention are as follows: The vacuum standard leak hole of the present invention is provided with an upper connecting member, a lower connecting member, a baffle, an upper indium ring, a lower indium ring and an indium block, wherein the upper indium ring is embedded in the upper accommodating groove, and an upper indium ring is formed on the bottom end face of the upper indium ring. The lower indium ring is embedded in the lower accommodating groove, and a lower indium ring is formed on the top end face of the lower indium ring. The indium block is embedded in the flow-through hole. The helium or other leak-indicating gas flowing in from the air inlet passes through the inner wall of the upper indium ring, the interior of the upper indium ring, the bottom face of the upper indium ring, the top face of the indium block, the bottom face of the indium block, the top face of the lower indium ring, the interior of the lower indium ring and the inner wall of the lower indium ring in turn, and then flows out from the air outlet. Compared with the traditional vacuum standard leak hole, indium material is used as the permeation medium of the leak-indicating gas, and the tiny gas channel generated in the material after the indium material is greatly deformed is used as a trace permeation channel for the leak-indicating gas. In the upper indium ring, the leak-indicating gas is slightly permeated and diffused from the inside to the outside along the radial direction of the upper indium ring. Part of the leak-indicating gas that penetrates into the upper indium ring flows to the indium block, and the other part passes through the outer ring of the upper indium ring and diffuses into the atmosphere. In addition, the ratio of gas flowing to the indium block and the atmosphere through the upper indium ring can be quantitatively controlled, depending on the number and diameter of the indium blocks, that is, the number and diameter of the holes flowing through the baffle. The more the number or the larger the diameter, the greater the proportion of gas flowing to the indium block. The outer ring of the upper indium ring also serves to isolate the atmosphere. In the lower indium ring, the leak-indicating gas penetrates and diffuses in trace amounts from the outside to the inside along the radial direction of the lower indium ring. Part of the leak-indicating gas that penetrates into the lower indium ring diffuses to the air outlet through the outer ring of the lower indium ring, and the other part diffuses into the atmosphere through the outer ring of the lower indium ring. The ratio of gas flowing to the air outlet and the atmosphere through the lower indium ring can be quantitatively controlled. The outer ring of the lower indium ring also serves to isolate the atmosphere. On the whole, the trace permeation channel of the leak-indicating gas is constructed by means of the upper indium ring, the indium block and the lower indium ring. Compared with the method in which the leak-indicating gas directly permeates along the vertical direction of the surface where the permeable membrane is located, the path for trace permeation is greatly extended. At the same time, part of the leak-indicating gas flowing into the permeation channel can be diffused into the atmosphere for loss. It should be pointed out that in the entire path of the leak-indicating gas flow, the resistance encountered is relatively large when flowing along the radial direction of the upper indium ring and along the radial direction of the lower indium ring, while the resistance encountered is relatively small when flowing from top to bottom along the indium block. Therefore, when the distance between the top surface of the upper connector and the bottom end of the lower connector remains unchanged, by compressing the thickness of the upper indium ring and the lower indium ring, or reducing the number and diameter of the flow-through holes, or increasing the distance between the center of the flow-through hole and the center of the baffle, the lower limit of the leakage rate of the vacuum standard leak hole can be significantly reduced, and a vacuum standard leak hole with a very small leakage rate can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of some specific embodiments of a vacuum standard leak of the present invention;

[0029] Figure 2 yes Figure 1The schematic diagram of the vacuum standard leak hole shown before being combined;

[0030] Figure 3 yes Figure 1 A partial enlarged view of the middle A area;

[0031] Figure 4 yes Figure 1 The schematic structural diagrams of some specific embodiments of the baffles in the vacuum standard leak are shown;

[0032] Figure 5 It is a schematic structural diagram of some specific embodiments of a test device of the present invention.

[0033] In the accompanying drawings, 100, vacuum standard leak; 110, upper connecting piece; 111, air inlet; 112, upper accommodating groove; 113, raised portion; 114, threaded hole; 120, lower connecting piece; 121, air outlet; 122, lower accommodating groove; 123, groove; 130, baffle; 131, flow-through hole; 140, upper indium ring; 141, upper indium ring; 150, lower indium ring; 151, lower indium ring; 160, indium block; 210, gas cylinder; 220, mass spectrometer chamber; 231, auxiliary fore-stage pump; 232, fore-stage pump; 240, quadrupole mass spectrometer; 250, liquid nitrogen cold trap; 260, molecular pump group; 270, ion pump; 280, getter pump; 291, dynamic method standard leak; 292, accumulation method standard leak. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] As described in the background technology, currently, the lower limit of the leakage rate of the quartz helium-infiltrated standard leak has reached its limit. With the continuous improvement of leak detection technology, it is necessary to further reduce the lower limit of the leakage rate of the vacuum standard leak. If the leakage rate is reduced by several orders of magnitude on the basis of the existing leakage rate, the area A of the quartz film needs to be reduced by several orders of magnitude, or the thickness D of the quartz film needs to be increased by several orders of magnitude. However, it is unrealistic to make the permeation area of ​​the quartz film very small or to make the thickness of the quartz film very large in actual production. Therefore, how to further reduce the lower limit of the leakage rate of the vacuum standard leak to meet higher leak detection requirements has become a technical problem that needs to be solved urgently by those skilled in the art.

[0036] To solve the above problems, refer to Figure 1 , Figure 2 , Figure 3 and Figure 4On the one hand, the present invention provides a vacuum standard leak hole 100, including an upper connecting member 110, a lower connecting member 120, a baffle 130, an upper indium ring 140, a lower indium ring 150 and an indium block 160. The lower connecting member 120 is connected to the upper connecting member 110. An air inlet 111 is formed on the upper connecting member 110. An air outlet 121 is formed on the lower connecting member 120. The air outlet 121 is arranged vertically opposite to the air inlet 111. An upper accommodating groove 112 of a closed annular structure is formed on the bottom surface of the upper connecting member 110. The upper accommodating groove 112 facilitates the positioning and installation of the upper indium ring 140. A lower accommodating groove 122 of a closed annular structure is formed on the top surface of the lower connecting member 120. The lower accommodating groove 122 facilitates the positioning and installation of the lower indium ring 150. The baffle 130 is installed between the upper connecting member 110 and the lower connecting member 120 to isolate the air inlet 111 from the air outlet 121. A flow hole 131 is formed on the baffle 130. The flow hole 131 is offset from the air inlet 111 / air outlet 121, and is directly opposite to the upper accommodating groove 112 and the lower accommodating groove 122. The upper indium ring 140 is embedded in the upper accommodating groove 112. The lower indium ring 150 is embedded in the lower accommodating groove 122. When the upper connecting member 110 and the lower connecting member 120 are connected and closed, the bottom end surface of the upper indium ring 140 is compressed and deformed to form an upper indium ring 141, and the top end surface of the lower indium ring 150 is compressed and deformed to form a lower indium ring 151. The indium block 160 is embedded in the flow hole 131. Figure 1 and Figure 3The direction of the middle arrow shows the flow direction of the leak gas. The helium or other leak gas flowing in from the air inlet 111 passes through the inner wall of the upper indium ring 141, the interior of the upper indium ring 141, the bottom surface of the upper indium ring 141, the top surface of the indium block 160, the bottom surface of the indium block 160, the top surface of the lower indium ring 151, the interior of the lower indium ring 151 and the inner wall of the lower indium ring 151, and then flows out from the air outlet 121. Compared with the traditional vacuum standard leak hole 100, indium material is used as the permeation medium of the leak gas, and the tiny gas channel generated in the material after the indium material is greatly deformed is used as a trace permeation channel for the leak gas. In the upper indium ring 141, the leak gas is slightly permeated and diffused from the inside to the outside along the radial direction of the upper indium ring 141. Part of the leak gas that penetrates into the upper indium ring 141 flows to the indium block 160, and the other part passes through the outer ring of the upper indium ring 141 and diffuses into the atmosphere. The outer ring of the upper indium ring 141 also serves to isolate the atmosphere. In the lower indium ring 151, the leakage indicator gas diffuses in trace amounts from the outside to the inside along the radial direction of the lower indium ring 151. A portion of the leakage indicator gas that penetrates into the lower indium ring 151 passes through the outer ring of the lower indium ring 151 and diffuses to the gas outlet 121, and another portion passes through the outer ring of the lower indium ring 151 and diffuses into the atmosphere. The outer ring of the lower indium ring 151 also serves to isolate the atmosphere. On the whole, a trace permeation channel for the leakage indicator gas is constructed with the help of the upper indium ring 141, the indium block 160 and the lower indium ring 151. Compared with the method in which the leakage indicator gas directly permeates in the vertical direction of the surface where the permeable membrane is located, the path for trace permeation is greatly extended. At the same time, part of the leakage indicator gas that flows into the permeation channel can be diffused into the atmosphere for loss. It should be pointed out that in the entire flow path of the leak-indicating gas, the resistance encountered when flowing along the radial direction of the upper indium ring 141 and the lower indium ring 151 is relatively large, while the resistance encountered when flowing from top to bottom along the indium block 160 is relatively small. Therefore, when the distance between the top surface of the upper connector 110 and the bottom end of the lower connector 120 remains unchanged, by compressing the thickness of the upper indium ring 141 and the lower indium ring 151, or reducing the number and diameter of the flow-through holes, or increasing the distance between the center of the flow-through hole and the center of the baffle, the lower limit of the leakage rate of the vacuum standard leak hole 100 can be significantly reduced, and a vacuum standard leak hole 100 with an extremely small leakage rate can be obtained.

[0037] It should be noted that if the leak-indicating gas is slightly infiltrated along the radial direction of the quartz film, it is difficult to implement. Even if the leak-indicating gas is slightly infiltrated along the radial direction of the quartz film, the test results show that the radial leakage rate of the quartz film is still an order of magnitude higher than the radial leakage rate of the indium film. Therefore, an indium film is used. In theory, the indium film can also penetrate longitudinally, but according to the test results, the internal gas permeation principle of the indium material is due to a large deformation, resulting in a large number of microscopic crystal defects inside the indium material. The reason why radial penetration is successful is that the bottom end of the upper indium ring 140 is squeezed and extended into the upper indium ring 141, and the top end of the lower indium ring 150 is squeezed and extended into the lower indium ring 151, and the indium sheet itself is difficult to deform greatly in the thickness direction, and it is not feasible to directly use the leak-indicating gas to penetrate along the vertical direction of the surface where the indium sheet is located.

[0038] The assembly process of the vacuum standard leak 100 is as follows:

[0039] First, a section of indium wire is bent into an upper indium ring 140, and the upper indium ring 140 is installed in the upper receiving groove 112. Then, a section of indium wire is bent into a lower indium ring 150, and the lower indium ring 150 is installed in the lower receiving groove 122. Then, the indium block 160 is embedded in the flow hole 131 of the baffle 130, and then the baffle 130 is placed between the upper connector 110 and the lower connector 120, and then the upper connector 110 and the lower connector 120 are connected. Since the cross-sectional diameter of the upper indium ring 140 is larger than the cross-sectional area of ​​the upper receiving groove 112, during the connection process between the upper connector 110 and the lower connector 120, the bottom end of the upper indium ring 140 is tightly attached to the top surface of the baffle 130, and when squeezed, it will "overflow" from the upper receiving groove 112 due to its ductility and fluidity, forming an upper indium ring 141 filled between the upper connector 110 and the baffle 130. Since the cross-sectional diameter of the lower indium ring 150 is larger than the cross-sectional area of ​​the lower receiving groove 122, during the connection process between the upper connector 110 and the lower connector 120, the top of the lower indium ring 150 is in close contact with the bottom of the baffle 130. When squeezed, it will "overflow" from the lower receiving groove 122 due to its ductility and fluidity, forming a lower indium ring 151 filled between the lower connector 120 and the baffle 130. At the same time, under the action of the squeezing force, the upper indium ring 141, the indium block 160 and the lower indium ring 151 are squeezed into an integrated structure, which not only avoids the influence of the upstream high-purity leak-indicating gas environment and the atmospheric environment on the downstream leakage rate, but also forms two diversions for the helium gas during the penetration process, further reducing the lower limit of the leakage rate.

[0040] Preferably, the air inlet 111 is formed in the middle of the upper connecting member 110 , and the air outlet 121 is formed in the middle of the lower connecting member 120 .

[0041] Specifically, in the exemplary embodiment, a protrusion 113 is formed at the bottom end of the upper connecting member 110, and correspondingly, a groove 123 adapted to the protrusion 113 is formed at the top end of the lower connecting member 120. The protrusion 113 cooperates with the groove 123 to improve the stability of the connection and prevent the upper connecting member 110 and the lower connecting member 120 from being misaligned. The upper accommodating groove 112 is formed on the bottom end surface of the protrusion 113, and the lower accommodating groove 122 is formed on the bottom end surface of the groove 123. The blocking piece 130 is installed in the groove 123 to limit the movement of the blocking piece 130 in the radial direction.

[0042] Preferably, the upper connecting member 110 and the lower connecting member 120 are flanges, which increase the contact area when the upper connecting member 110 and the lower connecting member 120 are connected, thereby improving the stability of the connection between the upper connecting member 110 and the lower connecting member 120. The material of the upper connecting member 110, the lower connecting member 120 and the baffle 130 is stainless steel, which has high strength and rigidity. At the same time, the stainless steel material has the property that the leak-indicating gas is not easy to penetrate and adsorb.

[0043] In some embodiments, the upper connecting member 110 and the lower connecting member 120 are detachably connected to facilitate assembly, use, disassembly and replacement of the vacuum standard leak 100. Specifically, the connection can be made by screwing, riveting or clamping.

[0044] In other embodiments, the upper connecting member 110 and the lower connecting member 120 are connected in an undetachable manner to improve the stability of the connection between the upper connecting member 110 and the lower connecting member 120. Specifically, welding can be used for connection.

[0045] In the example, if Figure 1 and Figure 2 As shown, the edge of the upper connecting member 110 is evenly provided with three, four, five or six threaded holes 114 along the circumferential direction, and correspondingly, the edge of the lower connecting member 120 is also evenly provided with three, four, five or six threaded holes 114 along the circumferential direction. The upper connecting member 110 and the lower connecting member 120 are connected by bolts and nuts through the threaded holes 114. It should be noted that when the flange surfaces of the upper connecting member 110 and the lower connecting member 120 are fitted, a 1mm gap is left in the middle. Due to the strong ductility of indium, it will plastically deform, and the change of preload force will make the structure loose, so the bolts and nuts need to be tightened. The thickness of the upper indium ring 140 and the lower indium ring 150 is compressed and adjusted by increasing the thickness of the baffle 130. Under the action of the preload force of the bolts and nuts, the upper indium ring 141, the indium block 160 and the lower indium ring 151 are squeezed into an integrated structure. It not only avoids the influence of the upstream high-purity leak-indicating gas environment and the atmospheric environment on the downstream leak rate, but also forms two diversions of helium during the permeation process, further reducing the lower limit of the leak rate.

[0046] Specifically, in the example, Figure 1 and Figure 4 As shown, there are one, two, three, four or five flow-through holes 131, which are evenly distributed along the circumference of the baffle 130. Correspondingly, there are three, four or five indium blocks 160, which are embedded in the flow-through holes 131 in a one-to-one correspondence with the flow-through holes 131. The baffle 130 is circular, with a diameter of 20 mm and a thickness of 0.5 mm. The aperture of each flow-through hole 131 is 1 mm, and the distance between the center of the hole and the center of the baffle 130 is 4.5 mm. The diameter of the cross section of each indium block 160 is 1 mm, and the axial length is 0.5 mm. The diameter of the cross section of the upper indium ring 140 and the lower indium ring 150 is 2 mm. The inner diameter of the upper indium ring is 4 mm, and the outer diameter is 14 mm. The inner diameter of the lower indium ring is 4 mm, and the outer diameter is 14 mm. In addition to controlling the thickness of the upper indium ring 141 and the lower indium ring 151, the leakage rate of the vacuum standard leak hole 100 can be further reduced by increasing the distance from the center of the flow hole 131 to the center of the baffle 130, reducing the aperture of the flow hole 131, or reducing the number of flow holes 131, so that the lower limit of the leakage rate is more controllable.

[0047] Reference Figure 5On the other hand, the present invention also provides a test device, including a gas cylinder 210, a mass spectrometer chamber 220, an auxiliary fore-stage pump 231, a quadrupole mass spectrometer 240, a liquid nitrogen cold trap 250, a molecular pump group 260, an ion pump 270, an aspirator pump 280, a dynamic method standard leak 291, an accumulation method standard leak 292, a fore-stage pump 232, and a vacuum standard leak 100 provided in any embodiment. The vacuum standard leak 100 is connected to the gas cylinder 210 and the mass spectrometer chamber 220 respectively. The auxiliary fore-stage pump 231 is connected to the upstream pipeline of the test piece. The quadrupole mass spectrometer 240 is connected to the mass spectrometer chamber 220. The liquid nitrogen cold trap 250 is arranged on the periphery of the mass spectrometer chamber 220. The molecular pump group 260 is connected to the mass spectrometer chamber 220. The ion pump 270 is connected to the mass spectrometer chamber 220, and is used to maintain a high vacuum environment in the mass spectrometer chamber 220 when the system is shut down. The getter pump 280 is connected to the mass spectrometer chamber 220. The dynamic method standard leak 291 is connected to the mass spectrometer chamber 220. The accumulation method standard leak 292 is connected to the mass spectrometer chamber 220. The fore pump 232 is connected to the molecular pump group 260. It should be noted that the leak rates of the dynamic method standard leak 291 and the accumulation method standard leak 292 are calibrated and known, and the vacuum standard leak 100 is used as the leak to be measured. The leak rate of the vacuum standard leak 100 of the present invention can be measured with the help of a test device. The gas cylinder 210 is used to inflate and discharge the vacuum standard leak 100. The auxiliary fore pump 231 is used to evacuate the vacuum standard leak 100; when the vacuum accumulation method is used to detect leaks in the vacuum standard leak 100, the liquid nitrogen cooling hydrazine is filled with liquid nitrogen so that the liquid nitrogen wraps the mass spectrometer chamber 220, and the mass spectrometer chamber 220 is pre-cooled. After the liquid nitrogen in the liquid nitrogen cooling hydrazine is evaporated and the temperature in the mass spectrometer chamber 220 is lowered, the liquid nitrogen cooling hydrazine is filled with liquid nitrogen again. The test equipment can perform positive pressure leak detection, negative pressure leak detection and back pressure leak detection on the vacuum standard leak 100. When the leak rate is greater than 1×10 -12 Pa·m 3 When testing a vacuum standard leak of 100 / s, the vacuum dynamic leak detection method is used; when the leak rate is less than 1×10 -12 Pa·m 3 When testing the vacuum standard leak of 100 / s, the vacuum accumulation leak detection method is adopted.

[0048] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0049] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0050] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0052] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A vacuum standard leak, characterized in that: include: The upper connecting member is formed with an air inlet and an upper receiving groove is formed on the bottom surface; The lower connecting piece is formed with an air outlet; the air outlet is arranged opposite to the air inlet; A lower accommodating groove is formed on the top surface of the lower connecting member; the lower connecting member is connected to the upper connecting member; A baffle installed between the upper connecting member and the lower connecting member to isolate the air inlet from the air outlet; a flow-through hole is formed on the baffle; An upper indium ring is embedded in the upper accommodating groove, and an upper indium ring is formed at the bottom end; A lower indium ring is embedded in the lower accommodating groove and has a lower indium ring formed on the top; An indium block, embedded in the flow hole; The helium gas flowing in from the air inlet passes through the inner wall of the upper indium ring, the interior of the upper indium ring, the bottom surface of the upper indium ring, the indium block, the top surface of the lower indium ring, the interior of the lower indium ring and the inner wall of the lower indium ring in sequence, and then flows out from the air outlet.

2. The vacuum standard leak according to claim 1, characterized in that: A convex portion is formed at the bottom end of the upper connecting member; and the upper accommodating groove is formed at the bottom end of the convex portion; A groove matched with the protruding portion is formed at the top end of the lower connecting member; the lower accommodating groove is formed at the bottom end of the groove; and the blocking piece is installed in the groove.

3. The vacuum standard leak according to claim 1, characterized in that: The upper connecting piece and the lower connecting piece are flanges.

4. The vacuum standard leak according to claim 1, characterized in that: The upper connecting member and the lower connecting member are detachably connected.

5. The vacuum standard leak according to claim 1, characterized in that: There are four flow-through holes, which are evenly distributed along the circumference of the baffle; correspondingly, there are four indium blocks, which are embedded in the flow-through holes in a one-to-one correspondence with the four flow-through holes.

6. The vacuum standard leak according to claim 5, characterized in that: The baffle is circular, with a diameter of 20 mm and a thickness of 0.5 mm; The diameter of each of the flow-through holes is 1 mm, and the distance between the center of the hole and the center of the baffle is 4.5 mm; The cross-section of each indium block has a diameter of 1 mm and an axial length of 0.5 mm; The inner diameter of the upper indium ring is 4 mm and the outer diameter is 14 mm; The inner diameter of the lower indium ring is 4 mm and the outer diameter is 14 mm.

7. The vacuum standard leak according to claim 1, characterized in that: The upper connecting piece, the lower connecting piece and the blocking piece are made of stainless steel.

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