Standard leak hole and preparation method thereof

Abstract

The invention relates to the technical field of vacuum leak detection, in particular to a standard leak hole and a preparation method thereof.The standard leak hole comprises a first gas barrier layer, a permeable layer and a second gas barrier layer, the first gas barrier layer is attached to the upper surface of the permeable layer, and the first gas barrier layer is provided with a gas inlet communicated with the permeable layer; the second gas barrier layer is attached to the lower surface of the permeable layer, so that the permeable layer is clamped between the first gas barrier layer and the second gas barrier layer, and the leakage indicating gas transversely flows in the permeable layer. According to the application, the first gas barrier layer and the second gas barrier layer are arranged on the upper side and the lower side of the permeable layer, so that the transverse flow of the leakage indicating gas in the permeable layer can be controlled, and the thickness of the permeable layer can be adjusted to be reduced from the millimeter magnitude to the nanometer magnitude compared with the longitudinal flow of the leakage indicating gas in the permeable layer; therefore, the leak rate lower limit of the standard leak hole is obviously reduced.

Description

Technical Field

[0001] The present application relates to the technical field of vacuum leak detection, and in particular to a standard leak hole and a preparation method thereof. Background Art

[0002] Vacuum leak detection technology is a technology that determines whether a vacuum system, container or device is leaking, and determines the location of the leak hole and the size of the leak rate. Common leak detection methods include pressure change leak detection, bubble leak detection, mass spectrometry leak detection and other methods. Among them, mass spectrometry leak detection has become one of the most widely used leak detection methods due to its high leak detection sensitivity. The mass spectrometry leak detection method uses a mass spectrometer to convert the flow of the leak-indicating gas leaking through the 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.

[0003] A standard leak is a device with a constant leak rate under specified conditions. It is generally divided into a channel-type standard leak and a permeation-type standard leak. A permeation-type leak is a leak caused by the permeation of a leak-tester gas, while a channel-type leak is a leak caused by a channel that can restrict the flow of a leak-tester gas. Since the lower limit of the leak rate of a permeation-type standard leak is significantly lower than that of a channel-type standard leak, most mass spectrometers use permeation-type standard leaks. With the continuous improvement of leak detection technology, it is necessary to continuously reduce the leak rate of a standard leak. This can be achieved by using permeable materials with a lower permeability, increasing the film thickness, and reducing the permeation area of ​​the film. If the leak rate is to be reduced by several orders of magnitude based on the existing leak rate, the lower limit of the current standard leak has reached its limit.

[0004] In view of this, this application is specially filed. Summary of the invention

[0005] The present application provides a standard leak hole to solve the problem of how to reduce the leakage rate of the standard leak hole.

[0006] On the one hand, the present application provides a standard leak, comprising:

[0007] Permeable layer;

[0008] A first gas barrier layer, wherein the first gas barrier layer is disposed in contact with the upper surface of the permeable layer, and the first gas barrier layer is provided with an air inlet communicating with the permeable layer;

[0009] The second gas barrier layer is arranged in contact with the lower surface of the permeable layer so that the permeable layer is sandwiched between the first gas barrier layer and the second gas barrier layer, and the leakage gas flows horizontally in the permeable layer.

[0010] In some embodiments, the standard leak hole further includes an upper flange and a lower flange, the upper flange and the lower flange enclose a receiving cavity for receiving the first gas barrier layer, the permeable layer and the second gas barrier layer, and the bottom of the lower flange is provided with an exhaust channel communicating with the receiving cavity;

[0011] A first gap is formed between the outer peripheral side of the permeable layer and the upper flange, and a second gap is formed between the second gas barrier layer and the lower flange;

[0012] The standard leak hole is configured so that the leak detection gas flows into the permeable layer through the gas inlet, and a portion of the leak detection gas that passes through the permeable layer passes through the first gap and the second gap in sequence, and finally flows out from the exhaust channel.

[0013] In some embodiments, the standard leak hole further includes a pressure cover, the pressure cover passes through the upper flange and is arranged in contact with the first gas barrier layer, and the pressure cover is provided with an air inlet channel connected to the air inlet.

[0014] In some embodiments, a third gap is formed between the gland and the first gas barrier layer, and a fourth gap connected to the third gap is formed between the gland and the upper flange;

[0015] The standard leak hole is constructed so that the leakage-indicating gas flows into the air inlet passage, a part of the leakage-indicating gas passes through the air inlet passage and flows into the permeation layer through the air inlet port, a part of the leakage-indicating gas passes through the air inlet passage and sequentially passes through the third gap and the fourth gap, and is finally discharged into the outside.

[0016] In some embodiments, the first gas barrier layer is disposed below the upper flange, a third gap is formed between the gland and the first gas barrier layer, and a fifth gap is formed between the upper flange and the first gas barrier layer and is connected to the third gap and the first gap respectively;

[0017] Wherein, the standard leak hole is constructed so that the leakage indicating gas flows into the intake channel, a part of the leakage indicating gas passes through the intake channel and flows into the permeation layer, a part of the leakage indicating gas passes through the intake channel and passes through the third gap, the fifth gap, the first gap, the second gap in sequence, and finally flows out from the exhaust channel.

[0018] In some embodiments, the upper flange is sealed to the first gas barrier layer via a first seal; and / or

[0019] The upper flange and the lower flange are sealed together by a second sealing member; and / or

[0020] The pressure cover is sealed and attached to the first gas barrier layer through a third sealing member.

[0021] In some embodiments, the lower flange has a boss for supporting the second gas barrier layer, the boss is provided with an air flow groove extending along the length direction and / or width direction of the permeable layer, and the air flow groove is connected to the exhaust channel.

[0022] In some embodiments, the material of the permeation layer is one or more of quartz, PMMA, graphene, and graphene oxide; and / or

[0023] The first gas barrier layer and / or the second gas barrier layer is made of metal material.

[0024] In some embodiments, the cross-section of the permeable layer is rectangular, and the leakage rate of the standard leak hole can be expressed by the following formula:

[0025]

[0026] In the above formula, H is the leakage rate of the standard leak hole, Pa·m 3 / s; K is the permeability coefficient of the permeable layer, Pa·m 3 / (s·cm 2 ·Pa·mm -1 ) ; W is the width of the permeation layer, cm; L is the length of the permeation layer, cm; H is the height of the permeation layer, mm; p is the partial pressure difference of the permeating gas between the upstream and downstream, Pa.

[0027] On the other hand, the present application also provides a method for preparing the standard leak hole applied to any of the above-mentioned methods, comprising the following steps:

[0028] The first gas barrier layer is plated on the upper surface of the permeable layer, and an air inlet with a predetermined size is formed on the first gas barrier layer by masking;

[0029] The second gas barrier layer is plated on the lower surface of the permeable layer.

[0030] After adopting the above technical solution, the present application has the following beneficial effects compared with the prior art.

[0031] 1. The standard leak hole in the present application can control the lateral flow of the leak-indicating gas in the permeation layer by setting the first gas barrier layer and the second gas barrier layer on the upper and lower sides of the permeation layer. Compared with the longitudinal flow of the leak-indicating gas in the permeation layer, it is more conducive to adjusting the thickness of the permeation layer from the millimeter level to the nanometer level, thereby significantly reducing the lower limit of the leakage rate of the standard leak hole.

[0032] 2. The preparation method of the standard leak hole in the present application has the characteristics of small thickness, large area, and lateral flow of the leak-indicating gas. Compared with the standard leak hole in which the leak-indicating gas flows longitudinally, the leakage rate of the standard leak hole can be significantly reduced by changing the flow direction of the leak-indicating gas while keeping the permeable material and structure unchanged, thereby achieving the purpose of lowering the lower limit of the permeable standard leak hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a cross-sectional view of a standard leak hole in an embodiment of the present application;

[0034] Figure 2 is a cross-sectional view of the leakage hole body in the embodiment of the present application;

[0035] Figure 3 is a schematic diagram of the flow of leakage gas in a standard leakage hole in an embodiment of the present application;

[0036] Figure 4 is a schematic diagram of the flow of leakage gas in the permeation layer in the embodiment of the present application;

[0037] Figure 5 is a cross-sectional view of the lower flange in the embodiment of the present application;

[0038] Figure 6 is a top view of the lower flange in the embodiment of the present application;

[0039] Figure 7 It is a logic block diagram of the method for preparing a standard leak hole in the embodiment of the present application.

[0040] In the figure: 100, standard leak hole; 101, first gap; 102, second gap; 103, fourth gap; 104, accommodating chamber; 110, upper flange; 120, lower flange; 121, boss; 1211, air flow groove; 122, exhaust channel; 123, first connecting hole; 130, leak hole body; 131, first gas barrier layer; 1311, air inlet; 132, permeation layer; 133, second gas barrier layer; 140, pressure cover; 141, air inlet channel; 150, first sealing member; 160, second sealing member; 170, third sealing member; 180, first fastener; 181, first bolt; 182, first nut; 190, second fastener. DETAILED DESCRIPTION

[0041] The technical solution of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0042] On the one hand, a standard leak hole 100 is provided in the embodiment of the present application, which can be applied to a mass spectrometer. For the specific structure of the standard leak hole 100, please refer to Figures 1 to 6 , which includes a leakage hole body 130, which has a first gas barrier layer 131, a permeation layer 132 and a second gas barrier layer 133 arranged in sequence from top to bottom, wherein the first gas barrier layer 131 is bonded to the upper surface of the permeation layer 132, and the first gas barrier layer 131 is provided with an air inlet 1311 connected to the permeation layer 132; the second gas barrier layer 133 is bonded to the lower surface of the permeation layer 132, so that the permeation layer 132 is clamped between the first gas barrier layer 131 and the second gas barrier layer 133, and the leakage gas flows horizontally in the permeation layer 132.

[0043] According to the standard leak hole 100 of the present application, by arranging the first gas barrier layer 131 and the second gas barrier layer 133 on the upper and lower sides of the permeable layer 132, the lateral flow of the leakage-indicating gas in the permeable layer 132 can be controlled. Compared with the longitudinal flow of the leakage-indicating gas in the permeable layer 132, it is more conducive to adjusting the thickness of the permeable layer 132 from the millimeter level to the nanometer level, thereby significantly reducing the lower limit of the leakage rate of the standard leak hole 100.

[0044] like Figure 1 , Figure 3 , Figure 5 and Figure 6 As shown, the standard leak hole 100 also includes an upper flange 110 and a lower flange 120, the upper flange 110 and the lower flange 120 surround a receiving cavity 104 for receiving the leak hole body 130, and the bottom of the lower flange 120 is provided with an exhaust passage 122 connected to the receiving cavity 104; a first gap 101 is formed between the outer peripheral side of the permeable layer 132 and the upper flange 110, and a second gap 102 is formed between the second gas barrier layer 133 and the lower flange 120, wherein the standard leak hole 100 is constructed such that The leakage indicator gas flows into the permeation layer 132 through the air inlet 1311, and a part of the leakage indicator gas that passes through the permeation layer 132 passes through the first gap 101 and the second gap 102 in sequence, and finally flows out from the exhaust channel 122. By controlling the leakage indicator gas to turn multiple times in the permeation layer 132, the first gap 101, the second gap 102 and the exhaust channel 122, not only can the leakage indicator gas be made to flow horizontally in the permeation layer 132, but the leakage indicator gas can also be controlled to finally flow out of the exhaust channel 122.

[0045] like Figure 1 and Figure 3As shown, the standard leak hole 100 also includes a pressure cap 140, which is penetrated by an upper flange 110 and is arranged in contact with the first gas barrier layer 131. The pressure cap 140 is provided with an air inlet channel 141 connected to the air inlet 1311, so that the leakage gas flows into the leak hole body 130 from the air inlet channel 141 of the pressure cap 140, and then passes through the first gap 101 and the second gap 102 in sequence, and finally flows out from the exhaust channel 122.

[0046] like Figure 1 and Figure 3 As shown, a third gap is formed between the pressure cover 140 and the first gas barrier layer 131, and a fourth gap 103 connected to the third gap is formed between the pressure cover 140 and the upper flange 110, wherein the standard leak hole 100 is constructed so that the leakage indicating gas flows into the air inlet channel 141, a part of the leakage indicating gas passes through the air inlet channel 141 and flows into the permeation layer 132 through the air inlet 1311, a part of the leakage indicating gas passes through the air inlet channel 141 and passes through the third gap and the fourth gap 103 in sequence, and is finally discharged into the outside, thereby further adjusting the lower limit of the leakage rate of the standard leak hole 100.

[0047] like Figure 1 and Figure 3 As shown, the first gas barrier layer 131 is arranged below the upper flange 110, a third gap is formed between the pressure cover 140 and the first gas barrier layer 131, and a fifth gap connected to the third gap and the first gap 101 is formed between the upper flange 110 and the first gas barrier layer 131, wherein the standard leak hole 100 is configured so that the leakage-indicating gas flows into the air inlet channel 141, a part of the leakage-indicating gas passes through the air inlet channel 141 and flows into the permeation layer 132 through the air inlet 1311, and a part of the leakage-indicating gas passes through the air inlet channel 141 The leak-indicating gas passes through the third gap, the fifth gap, the first gap 101, the second gap 102 in sequence, and finally flows out from the exhaust channel 122. The leak-indicating gas turns multiple times in the leak hole body 130, the first gap 101 and the second gap 102 and the third gap, the fifth gap, the first gap 101 and the second gap 102, and finally flows into the exhaust channel 122. By adjusting the gas flow rate and flow direction of the leak-indicating gas, the leakage rate of the standard leak hole 100 can be significantly reduced, thereby obtaining a standard leak hole 100 with an extremely small leakage rate.

[0048] like Figure 1 and Figure 3As shown, the upper flange 110 and the first gas barrier layer 131 are sealed together by the first seal 150, the upper flange 110 and the lower flange 120 are sealed together by the second seal 160, and the pressure cover 140 and the first gas barrier layer 131 are sealed together by the third seal 170, so that a part of the leakage gas passes through the air inlet channel 141 and passes through the third gap and the fourth gap 103 in sequence, and is finally discharged into the outside, and a part of the leakage gas passes through the air inlet channel 141 and passes through the third gap, the fifth gap, the first gap 101, the second gap 102 in sequence, and finally flows out from the exhaust channel 122.

[0049] As an optional embodiment, the first seal 150, the second seal 160 and the third seal 170 can be sealing rings. The sealing rings are simple in design and easy to use and maintain. The sealing rings have excellent sealing properties and can automatically improve the sealing effect under different pressures.

[0050] like Figure 1 , Figure 3 , Figure 5 and Figure 6 As shown, the upper flange 110 and the lower flange 120 are respectively provided with a first connecting hole 123 for the first fastener 180 to pass through, so that the upper flange 110 and the lower flange 120 are fixedly connected through the first fastener 180. Exemplarily, the first fastener 180 can be a threaded fastener, and the first fastener 180 includes a first bolt 181 and a first nut 182. The first bolt 181 passes through the first connecting hole 123 set on the upper flange 110 and the lower flange 120 in sequence, and then the first nut 182 is sleeved on the threaded portion of the first bolt 181 and tightened, so that the upper flange 110 and the lower flange 120 are firmly connected.

[0051] like Figure 1 and Figure 3 As shown, the pressure cover 140 and the upper flange 110 are respectively provided with second connecting holes for the second fastener 190 to pass through, so that the pressure cover 140 and the upper flange 110 are fixedly connected through the second fastener 190. Exemplarily, the first fastener 180 can be a bolt fastener, which passes through the second connecting holes provided on the pressure cover 140 and the upper flange 110 in sequence to tighten and fix the pressure cover 140 and the upper flange 110.

[0052] As an optional embodiment, the permeation layer 132 is made of a material that has a slight permeability to the leakage indicating gas. The material of the permeation layer 132 can be a non-metallic crystalline material, such as quartz; the material of the permeation layer 132 can also be a polymer material, such as PMMA (polymethyl methacrylate); the material of the permeation layer 132 can also be a two-dimensional material, such as graphene, graphene oxide, etc.

[0053] As an optional embodiment, the material of the first gas barrier layer 131 and / or the second gas barrier layer 133 is a metal material, such as gold, platinum, aluminum and other metal materials. The first gas barrier layer 131 and / or the second gas barrier layer 133 are closely combined with the permeable layer 132 by coating, for example, a metal film is coated on the surface of the permeable film by vacuum coating. The air inlet 1311 on the first gas barrier layer 131 is a channel for the leak gas to enter the permeable layer 132, which can be obtained by using a mask method during the coating process of the first gas barrier layer 131.

[0054] like Figure 1 , Figure 3 , Figure 5 and Figure 6 As shown, the lower flange 120 has a boss 121 for supporting the bottom of the second gas barrier layer 133, and the boss 121 is provided with an airflow groove 1211 extending in the length direction and / or width direction in the permeation layer 132. The airflow groove 1211 is connected to the exhaust channel 122, flows laterally in the permeation layer 132, flows out from the permeation layer 132 on both sides along its length direction, enters the first gap 101 and the second gap 102 in turn, and then enters the airflow groove 1211 of the lower flange 120, and finally flows out from the exhaust channel 122.

[0055] The leak body 130 can be made into a spherical, sheet-like, long cylindrical shape, etc. As an optional embodiment, the cross section of the permeable layer 132 is rectangular, that is, the permeable layer 132 is in sheet shape. The leakage rate of the standard leak 100 can be expressed by the following formula:

[0056]

[0057] In the above formula, Q is the leakage rate of the standard leak hole 100, Pa·m 3 / s;

[0058] K is the permeability coefficient of the permeable layer 132, Pa·m 3 / (s·cm 2 ·Pa·mm -1 );

[0059] A is the permeation area of ​​the permeation layer 132, cm 2 ;

[0060] D is the thickness of the permeable layer 132, mm;

[0061] W is the width of the permeable layer 132, cm;

[0062] L is the length of the permeable layer 132, cm;

[0063] H is the height of the permeable layer 132, mm;

[0064] p is the partial pressure difference of permeate gas between upstream and downstream, Pa.

[0065] When the material permeability coefficient K and the upstream and downstream pressure difference p remain unchanged, the leakage rate Q of the standard leak hole 100 is proportional to the area A of the permeable layer 132 and inversely proportional to the thickness D of the permeable layer 132. The leakage-indicating gas flows laterally in the permeable layer 132. The area A of the permeable layer 132 is the product of the width W of the permeable layer 132 and the length L of the permeable layer 132. The thickness D of the permeable layer 132 is equal to the height H of the permeable layer 132. With the development of thin film technology, the thickness of the film can be reduced from the millimeter level to the nanometer level. The leakage-indicating gas flows laterally in the permeable layer 132, which can greatly reduce the lower limit of the standard leak hole 100.

[0066] On the other hand, Figures 1 to 7 As shown, the present application also provides a method for preparing a standard leak hole 100, comprising the following steps:

[0067] Step S1: coating a first gas barrier layer 131 on the upper surface of the permeable layer 132, and forming an air inlet 1311 with a predetermined size on the first gas barrier layer 131 by masking;

[0068] Step S2: coating the second gas barrier layer 133 on the lower surface of the permeable layer 132 , so that the first gas barrier layer 131 , the permeable layer 132 and the second gas barrier layer 133 form a leak body 130 ;

[0069] Step S3: the leakage hole body 130 is arranged on the lower flange 120, the upper flange 110 is pressed on the leakage hole body 130, a first sealing member 150 is arranged between the upper flange 110 and the first gas barrier layer 131, a second sealing member 160 is arranged between the upper flange 110 and the lower flange 120, and a third sealing member 170 is arranged between the gland 140 and the first gas barrier layer 131;

[0070] Step S4: The first fastener 180 passes through the first connection holes 123 on the upper flange 110 and the lower flange 120 in sequence to fix the upper flange 110 and the lower flange 120 together;

[0071] Step S5: The second fastener 190 passes through the second connection holes on the gland 140 and the upper flange 110 in sequence to fix the gland 140 to the upper flange 110 .

[0072] According to the preparation method of the standard leak hole 100 of the present application, the standard leak hole 100 has the characteristics of small thickness, large area, and lateral flow of the leak-indicating gas. Compared with the standard leak hole 100 in which the leak-indicating gas flows longitudinally, by changing the flow direction of the leak-indicating gas while keeping the permeable material and structure unchanged, the leakage rate of the standard leak hole 100 can be significantly reduced, thereby achieving the purpose of lowering the lower limit of the permeable standard leak hole 100.

[0073] In the description of the present application, it should 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" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application 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 a limitation on the present application.

[0074] 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 this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0075] In this application, 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 connection; 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 this application can be understood according to specific circumstances.

[0076] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", 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 application. 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.

[0077] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A standard leak hole, characterized in that: include: Permeable layer; A first gas barrier layer, wherein the first gas barrier layer is disposed in contact with the upper surface of the permeable layer, and the first gas barrier layer is provided with an air inlet communicating with the permeable layer; The second gas barrier layer is arranged in contact with the lower surface of the permeable layer so that the permeable layer is sandwiched between the first gas barrier layer and the second gas barrier layer, and the leakage gas flows horizontally in the permeable layer.

2. The standard leak according to claim 1, characterized in that: The standard leak hole further comprises an upper flange and a lower flange, wherein the upper flange and the lower flange enclose a receiving cavity for receiving the first gas barrier layer, the permeable layer and the second gas barrier layer, and an exhaust passage communicating with the receiving cavity is provided at the bottom of the lower flange; A first gap is formed between the outer peripheral side of the permeable layer and the upper flange, and a second gap is formed between the second gas barrier layer and the lower flange; The standard leak hole is configured so that the leak detection gas flows into the permeable layer through the gas inlet, and a portion of the leak detection gas that passes through the permeable layer passes through the first gap and the second gap in sequence, and finally flows out from the exhaust channel.

3. The standard leak according to claim 2, characterized in that: The standard leak hole also includes a pressure cap, which passes through the upper flange and is arranged in contact with the first gas barrier layer. The pressure cap is provided with an air inlet channel connected with the air inlet.

4. The standard leak according to claim 3, characterized in that: A third gap is formed between the gland and the first gas barrier layer, and a fourth gap connected to the third gap is formed between the gland and the upper flange; The standard leak hole is constructed so that the leakage-indicating gas flows into the air inlet passage, a part of the leakage-indicating gas passes through the air inlet passage and flows into the permeation layer through the air inlet port, a part of the leakage-indicating gas passes through the air inlet passage and sequentially passes through the third gap and the fourth gap, and is finally discharged into the outside.

5. The standard leak according to claim 3, characterized in that: The first gas barrier layer is arranged below the upper flange, a third gap is formed between the gland and the first gas barrier layer, and a fifth gap is formed between the upper flange and the first gas barrier layer and is connected to the third gap and the first gap respectively; Wherein, the standard leak hole is constructed so that the leakage indicating gas flows into the intake channel, a part of the leakage indicating gas passes through the intake channel and flows into the permeation layer, a part of the leakage indicating gas passes through the intake channel and passes through the third gap, the fifth gap, the first gap, the second gap in sequence, and finally flows out from the exhaust channel.

6. The standard leak according to claim 3, characterized in that: The upper flange is sealed to the first gas barrier layer via a first seal; and / or The upper flange and the lower flange are sealed together by a second sealing member; and / or The pressure cover is sealed and attached to the first gas barrier layer through a third sealing member.

7. The standard leak according to claim 2, characterized in that: The lower flange has a boss for supporting the second gas barrier layer, and the boss is provided with an air flow groove extending along the length direction and / or width direction of the permeable layer, and the air flow groove is communicated with the exhaust channel.

8. The standard leak according to any one of claims 1 to 7, characterized in that: The material of the permeation layer is one or more of quartz, PMMA, graphene, and graphene oxide; and / or The first gas barrier layer and / or the second gas barrier layer is made of metal material.

9. The standard leak according to any one of claims 1 to 7, characterized in that: The cross section of the permeable layer is rectangular, and the leakage rate of the standard leak hole can be expressed by the following formula: In the above formula, H is the leakage rate of the standard leak hole, Pa·m 3 / s; K is the permeability coefficient of the permeable layer, Pa·m 3 / (s·cm 2 ·Pa·mm -1 ) ; W is the width of the permeation layer, cm; L is the length of the permeation layer, cm; H is the height of the permeation layer, mm; p is the partial pressure difference of the permeating gas between the upstream and downstream, Pa.

10. A method for preparing a standard leak hole as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: The first gas barrier layer is plated on the upper surface of the permeable layer, and an air inlet with a predetermined size is formed on the first gas barrier layer by masking; The second gas barrier layer is plated on the lower surface of the permeable layer.

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