A standard leak and method of making the same

Abstract

The application 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 permeation layer and a second gas barrier layer. The first gas barrier layer is attached to the upper surface of the permeation layer, and the first gas barrier layer is provided with an air inlet communicated with the permeation layer. The second gas barrier layer is attached to the lower surface of the permeation layer, so that the permeation layer is clamped between the first gas barrier layer and the second gas barrier layer, and the leak gas flows horizontally in the permeation layer. In the application, the first gas barrier layer and the second gas barrier layer are arranged on the upper and lower sides of the permeation layer, the horizontal flow of the leak gas in the permeation layer is controlled, the thickness of the permeation layer is more easily reduced from the millimeter level to the nanometer level relative to the vertical flow of the leak gas in the permeation layer, and therefore the lower limit of the leak rate of the standard leak hole is significantly reduced.

Description

TECHNICAL FIELD

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

[0002] Vacuum leak detection technology is a technology for judging whether a vacuum system, a container or a device leaks, determining the position and size of a leak. Common leak detection methods include pressure change leak detection, bubble leak detection, mass spectrometric leak detection and the like. Among them, the mass spectrometric leak detection method has become one of the most widely used leak detection methods due to its high sensitivity and other advantages. The mass spectrometric leak detection method uses a mass spectrometer to convert the flow rate of tracer gas leaked through a standard leak hole into an ion current of the mass spectrometer, and detects the leak rate by measuring the size of the ion current signal.

[0003] A standard leak hole is a device with a constant leak rate under specified conditions. It is generally divided into a channel type standard leak hole and a permeation type standard leak hole. The permeation type leak hole is a leak generated by the permeation of tracer gas, and the channel type leak hole is a leak generated by a channel that can restrict the flow of tracer gas. Since the lower limit of the leak rate of the permeation type standard leak hole is significantly lower than that of the channel type standard leak hole, mass spectrometers mostly use the permeation type standard leak hole. With the continuous improvement of leak detection technology, it is necessary to continuously reduce the leak rate of the standard leak hole. Measures such as using a permeation material with a smaller permeation rate, increasing the thickness of the film, and reducing the permeation area of the film can be taken. If the leak rate is to be reduced by several orders of magnitude on the basis of the existing leak rate, the lower limit of the leak rate of the current standard leak hole has reached the limit.

[0004] Therefore, the present application is proposed. SUMMARY

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

[0006] In one aspect, the present application provides a standard leak hole, comprising:

[0007] a permeation layer;

[0008] a first gas barrier layer, which is arranged in close contact with an upper surface of the permeation layer, and is provided with an air inlet in communication with the permeation layer;

[0009] a second gas barrier layer, which is arranged in close contact with a lower surface of the permeation layer, so that the permeation layer is clamped between the first gas barrier layer and the second gas barrier layer, and the tracer gas flows laterally in the permeation layer.

[0010] In some embodiments, the standard leak further comprises an upper flange and a lower flange, the upper flange and the lower flange enclosing a receiving cavity for receiving the first gas barrier layer, the permeation layer and the second gas barrier layer, a bottom of the lower flange being provided with an exhaust passage in communication with the receiving cavity;

[0011] a first gap is formed between an outer periphery of the permeation layer and the upper flange, and a second gap is formed between the second gas barrier layer and the lower flange;

[0012] In some embodiments, the standard leak is configured such that the tracer gas flows into the permeation layer through the gas inlet, a portion of the tracer gas passing through the permeation layer sequentially passes through the first gap, the second gap, and finally flows out from the exhaust passage.

[0013] In some embodiments, the standard leak further comprises a gland, the gland being arranged to adhere to the upper flange and the first gas barrier layer, the gland being provided with a gas inlet passage in communication with the gas inlet.

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

[0015] In some embodiments, the standard leak is configured such that the tracer gas flows into the gas inlet passage, a portion of the tracer gas passing through the gas inlet passage and flowing into the permeation layer through the gas inlet, and a portion of the tracer gas passing through the gas inlet passage and sequentially passing through the third gap, the fourth gap, and finally being exhausted to the outside.

[0016] In some embodiments, the first gas barrier layer is arranged to adhere to a lower portion of 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, the fifth gap being in communication with the first gap and the third gap respectively;

[0017] In some embodiments, the standard leak is configured such that the tracer gas flows into the gas inlet passage, a portion of the tracer gas passing through the gas inlet passage and flowing into the permeation layer, and a portion of the tracer gas passing through the gas inlet passage and sequentially passing through the third gap, the fifth gap, the first gap, the second gap, and finally flowing out from the exhaust passage.

[0018] In some embodiments, the upper flange and the first gas barrier layer are sealed and adhered by a first sealing member; and / or

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

[0020] The grommet is sealed and attached to the first gas barrier layer by a third seal.

[0021] In some embodiments, the lower flange has a boss for supporting the second gas barrier layer, and the boss is provided with gas flow grooves extending along the length and / or width direction of the permeation layer, and the gas flow grooves are in communication with the exhaust channel.

[0022] In some embodiments, the permeation layer is made of 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 a metal material.

[0024] In some embodiments, the permeation layer has a rectangular cross section, and the leak rate of the standard leak hole can be represented by the following formula:

[0025]

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

[0027] In another aspect, the present application also provides a preparation method of the standard leak hole described above, comprising the following steps:

[0028] Plating the first gas barrier layer on the upper surface of the permeation layer, and forming an air inlet with a predetermined size on the first gas barrier layer by mask method;

[0029] Plating the second gas barrier layer on the lower surface of the permeation layer.

[0030] Compared with the prior art, the present application has the following beneficial effects.

[0031] 1. The standard leak hole in the present application can control the lateral flow of the leak 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, which is more conducive to reducing the thickness of the permeation layer from the millimeter level to the nanometer level, thereby significantly reducing the lower limit of the leak rate of the standard leak hole.

[0032] ​​​​2, The preparation method of the standard leak hole in the application has the characteristics of small thickness, large area and lateral flow of the leak gas, compared with the standard leak hole with longitudinal flow of the leak gas, the leak rate of the standard leak hole can be significantly reduced by changing the flow direction of the leak gas under the condition of unchanged permeation material and structure, and the lower limit of the permeation type standard leak hole is realized. BRIEF DESCRIPTION OF DRAWINGS

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

[0034] Figure 2 is a sectional view of the leak hole body in the embodiment of the application;

[0035] Figure 3 is a schematic view of the flow of the leak gas in the standard leak hole in the embodiment of the application;

[0036] Figure 4 is a schematic view of the flow of the leak gas in the permeation layer in the embodiment of the application;

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

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

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

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

[0041] The technical solutions of the application will be described in detail below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0042] On the one hand, this application provides a standard leak 100, which can be applied to a mass spectrometer. For the specific structure of the standard leak 100, please refer to... Figures 1 to 6 It includes a leak body 130, which has a first gas barrier layer 131, a permeable layer 132 and a second gas barrier layer 133 arranged from top to bottom. The first gas barrier layer 131 is attached to the upper surface of the permeable layer 132 and has an air inlet 1311 communicating with the permeable layer 132. The second gas barrier layer 133 is attached to the lower surface of the permeable layer 132 so that the permeable layer 132 is sandwiched between the first gas barrier layer 131 and the second gas barrier layer 133, allowing the leaking gas to flow laterally in the permeable layer 132.

[0043] According to the standard leak 100 of this application, by providing a first gas barrier layer 131 and a second gas barrier layer 133 on the upper and lower sides of the permeation layer 132, the transverse flow of the leak indicator gas in the permeation layer 132 can be controlled. Compared with the longitudinal flow of the leak indicator gas in the permeation layer 132, it is more conducive to adjusting the thickness of the permeation layer 132 from the millimeter level to the nanometer level, thereby significantly reducing the lower limit of the leakage rate of the standard leak 100.

[0044] like Figure 1 , Figure 3 , Figure 5 and Figure 6 As shown, the standard leak 100 also includes an upper flange 110 and a lower flange 120. The upper flange 110 and the lower flange 120 enclose a receiving cavity 104 for accommodating the leak body 130. The bottom of the lower flange 120 is provided with an exhaust channel 122 communicating with the receiving cavity 104. A first gap 101 is formed between the outer periphery of the permeable layer 132 and the upper flange 110, and a second gap 102 is formed between the second gas-blocking layer 133 and the lower flange 120. The standard leak 100 is constructed such that... The leak-indicating gas flows into the permeation layer 132 through the inlet 1311. A portion of the leak-indicating gas passing 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 leak-indicating 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 leak-indicating gas flow laterally in the permeation layer 132, but the leak-indicating gas can also be controlled to finally flow out from the exhaust channel 122.

[0045] like Figure 1 and Figure 3As shown, the standard leak hole 100 further comprises a cover 140, which is arranged in abutment with the first gas barrier layer 131 through the upper flange 110, and the cover 140 is provided with an air inlet channel 141 which is in communication with the air inlet 1311, so that the tracer gas flows into the leak hole body 130 from the air inlet channel 141 of the cover 140, and then sequentially passes through the first gap 101 and the second gap 102, and finally flows out from the exhaust channel 122.

[0046] As shown in Figure 1 and Figure 3 , the third gap is formed between the cover 140 and the first gas barrier layer 131, and the fourth gap 103 is formed between the cover 140 and the upper flange 110, which is in communication with the third gap, wherein the standard leak hole 100 is configured such that the tracer gas flows into the air inlet channel 141, a part of the tracer 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 tracer gas passes through the air inlet channel 141 and sequentially passes through the third gap and the fourth gap 103, and finally is discharged to the outside, thereby further adjusting the lower limit of the leak rate of the standard leak hole 100.

[0047] As shown in Figure 1 and Figure 3 , the first gas barrier layer 131 is arranged in abutment below the upper flange 110, the third gap is formed between the cover 140 and the first gas barrier layer 131, and the fifth gap is formed between the upper flange 110 and the first gas barrier layer 131, which is in communication with the third gap and the first gap 101 respectively, wherein the standard leak hole 100 is configured such that the tracer gas flows into the air inlet channel 141, a part of the tracer 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 tracer gas passes through the air inlet channel 141 and sequentially passes through the third gap, the fifth gap, the first gap 101 and the second gap 102, and finally flows out from the exhaust channel 122, the tracer gas is turned 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 and flow direction of the tracer gas, the leak rate of the standard leak hole 100 can be significantly reduced, thereby obtaining a standard leak hole 100 with extremely small leak rate.

[0048] As shown in Figure 1 and Figure 3As shown, the upper flange 110 is sealed and attached to the first gas barrier layer 131 through the first seal 150, the upper flange 110 is sealed and attached to the lower flange 120 through the second seal 160, and the cover 140 is sealed and attached to the first gas barrier layer 131 through the third seal 170, so that part of the leakage gas passes through the gas inlet channel 141 and sequentially passes through the third gap, the fourth gap 103, and finally is discharged to the outside, and part of the leakage gas passes through the gas inlet channel 141 and sequentially passes through the third gap, the fifth gap, the first gap 101, the second gap 102, and finally flows out from the gas outlet 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 ring has a simple design, is convenient to use and maintain, has excellent sealing performance, and can automatically improve the sealing effect under different pressures.

[0050] As shown in Figure 1 , Figure 3 , Figure 5 and Figure 6 , the upper flange 110 and the lower flange 120 are respectively provided with first connecting holes 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, which includes a first bolt 181 and a first nut 182. The first bolt 181 sequentially passes through the first connecting holes 123 provided in the upper flange 110 and the lower flange 120, and then the first nut 182 is sleeved on the threaded portion of the first bolt 181 and is tightened, so that the upper flange 110 and the lower flange 120 are fixedly connected.

[0051] As shown in Figure 1 and Figure 3 , the 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 cover 140 and the upper flange 110 are fixedly connected through the second fastener 190. Exemplarily, the first fastener 180 can be a threaded fastener, which sequentially passes through the second connecting holes provided in the cover 140 and the upper flange 110 to tightly fix the cover 140 and the upper flange 110.

[0052] As an optional embodiment, the permeation layer 132 is made of a material that has a small amount of permeation to the leakage gas. The material of the permeation layer 132 can be a non-metallic crystal material, such as quartz. The material of the permeation layer 132 can also be a high 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 the like. The first gas barrier layer 131 and / or the second gas barrier layer 133 are tightly combined with the permeation layer 132 by plating, such as vacuum plating, to form a metal film on the surface of the permeation film. The gas inlet 1311 on the first gas barrier layer 131 is a channel for allowing the leaked gas to enter the permeation layer 132, which can be obtained by using a mask during the plating process of the first gas barrier layer 131.

[0054] As shown in Figure 1 , Figure 3 , Figure 5 and Figure 6 , 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 a gas flow groove 1211 extending in the length direction and / or the width direction of the permeation layer 132, which is in communication with the exhaust channel 122. The gas flow groove 1211 is in communication with the exhaust channel 122, and the gas flows transversely in the permeation layer 132, flows out from both sides of the permeation layer 132 along the length direction, enters the first gap 101 and the second gap 102 in turn, and then enters the gas flow groove 1211 of the lower flange 120, and finally flows out from the exhaust channel 122.

[0055] The leak hole body 130 can be spherical, sheet-shaped, long-cylindrical, and the like. As an optional embodiment, the cross section of the permeation layer 132 is rectangular, i.e., the permeation layer 132 is sheet-shaped, and the leak rate of the standard leak hole 100 can be represented by the following formula:

[0056]

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

[0058] K is the permeation coefficient of the permeation 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 permeation layer 132, mm;

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

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

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

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

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

[0066] On the other hand, as Figures 1 to 7 shown, the application also provides a preparation method of the standard leak hole 100, comprising the following steps:

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

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

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

[0070] Step S4: the first fastener 180 passes through the first connecting hole 123 on the upper flange 110 and the lower flange 120 in sequence, so as to fixedly connect the upper flange 110 and the lower flange 120;

[0071] Step S5: the second fastener 190 passes through the second connecting hole on the gland 140 and the upper flange 110 in sequence, so as to fixedly connect the gland 140 and the upper flange 110.

[0072] According to the preparation method of the standard leak hole 100 of the application, the standard leak hole 100 has the characteristics of small thickness, large area and lateral flow of leak gas, compared with the standard leak hole 100 with longitudinal flow of leak gas, under the condition of unchanged permeation material and structure, by changing the flow direction of leak gas, the leakage rate of the standard leak hole 100 can be significantly reduced, and the purpose of reducing the lower limit of the permeation type standard leak hole 100 is achieved.

[0073] In the description of the application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the application.

[0074] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0075] In this application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or communicate with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0076] In this application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like 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 application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0077] Although the embodiments of the application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as a limitation of the application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the application.

Claims

1. A standard leak hole, characterized in that, include: Upper flange; Lower flange; The leakage body includes: Permeable layer; A first gas barrier layer is provided, which is attached to 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 attached to 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, allowing the leaking gas to flow laterally in the permeable layer. The upper flange and the lower flange form a cavity for accommodating 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 cavity. A first gap is formed between the outer periphery 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 such that the leaking gas flows into the permeation layer through the air inlet, a portion of the leaking gas passing through the permeation layer passes sequentially through the first gap and the second gap, and finally flows out from the exhaust channel.

2. The standard leak hole according to claim 1, characterized in that, The standard leak hole also includes a pressure cap, which passes through the upper flange and is fitted to the first air barrier layer. The pressure cap is provided with an air intake channel communicating with the air inlet.

3. The standard leak hole according to claim 2, characterized in that, A third gap is formed between the gland and the first air barrier layer, and a fourth gap is formed between the gland and the upper flange, which communicates with the third gap; The standard leak hole is configured such that the leak indicator gas flows into the air inlet channel, a portion of the leak indicator gas passes through the air inlet channel and flows into the permeable layer through the air inlet, and a portion of the leak indicator gas passes through the air inlet channel and sequentially passes through the third gap and the fourth gap, and is finally discharged into the outside.

4. The standard leak hole according to claim 2, characterized in that, The first gas barrier layer is attached to the lower part of 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, which communicates with the third gap and the first gap respectively. The standard leak hole is configured such that the leak gas flows into the air intake channel, a portion of the leak gas passes through the air intake channel into the permeation layer, and a portion of the leak gas passes through the air intake channel and sequentially through the third gap, the fifth gap, the first gap, and the second gap, and finally flows out from the exhaust channel.

5. The standard leak hole according to claim 2, characterized in that, The upper flange is sealed to the first air barrier layer by a first sealing element; and / or The upper flange and the lower flange are sealed together by a second sealing element; and / or The gland and the first air barrier layer are sealed together by a third sealing element.

6. The standard leak hole according to claim 1, characterized in that, The lower flange has a boss for supporting the second gas barrier layer. The boss is provided with an airflow groove extending along the length and / or width direction of the permeable layer. The airflow groove is in communication with the exhaust channel.

7. The standard drain hole according to any one of claims 1 to 6, characterized in that, The permeation layer is made of one or more of the following materials: quartz, PMMA, graphene, and graphene oxide; and / or The first gas barrier layer and / or the second gas barrier layer are made of metal.

8. The standard leak hole according to any one of claims 1 to 6, characterized in that, The cross-section of the permeable layer is rectangular, and the leakage rate of the standard leak can be expressed by the following formula: In the above formula, H is the leakage rate of the standard leak, 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 permeated gas upstream and downstream (Pa).

9. A method for preparing a standard leak hole applicable to any one of claims 1 to 8, characterized in that, Includes the following steps: The first gas barrier layer is coated on the upper surface of the permeation layer, and an air inlet of a predetermined size is formed in the first gas barrier layer by means of a mask. The second gas barrier layer is coated on the lower surface of the permeation layer; The leak body is disposed on the lower flange, and the upper flange is pressed onto the leak body. A first sealing element is disposed between the upper flange and the first gas barrier layer, and a second sealing element is disposed between the upper flange and the lower flange. The standard leak also includes a pressure cap, and a third sealing element is disposed between the pressure cap and the first gas barrier layer. The first fastener passes through the first connecting holes on the upper flange and the lower flange in sequence to fix the upper flange and the lower flange together. The second fastener passes sequentially through the second connection hole on the gland and the upper flange to fix the gland and the upper flange together.

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