System and method for measuring flow resistance of capillary tube

Abstract

The invention relates to the technical field of capillary tubes, and provides a capillary tube flow resistance measuring system and method.The measuring system comprises a Dewar flask, a liquid storage tank, a pump, a mass flowmeter and a communicating pipeline, the Dewar flask is provided with an inner cavity, the liquid storage tank is used for storing a liquid refrigerating medium and communicates with the inner cavity, the communicating pipeline is detachably connected with the Dewar flask, and the pump is arranged in the Dewar flask; a first port of the communicating pipeline extends into the inner cavity, the first port is used for being communicated with the capillary tube, and the pump and the mass flow meter are both arranged on the communicating pipeline and located outside the Dewar. According to the invention, the problems that the flow resistance of the capillary tube is influenced by the temperature and the type of the refrigerating medium, and the measurement precision is low when the flow resistance of the capillary tube is measured by using a flow resistance calculation method or a room temperature measurement method when the liquid refrigerating medium with lower temperature flows in the prior art can be solved.

Description

Technical Field

[0001] The present application relates to the field of capillary technology, and in particular to a capillary flow resistance measurement system and method. Background Art

[0002] Refrigeration using liquid refrigerants such as liquid helium and liquid nitrogen is a common refrigeration method, and can be used for pre-cooling of low-temperature refrigerators such as dilution refrigeration and adiabatic demagnetization refrigeration. In the process of refrigeration using liquid refrigerants, the evaporation of the liquid refrigerant will lead to a decrease in the liquid refrigerant, so the liquid refrigerant needs to be replenished. In the process of replenishing the liquid refrigerant, a flow resistance element is usually used to control the replenishment rate of the liquid refrigerant to achieve a balance between the evaporation amount and the replenishment amount of the liquid refrigerant.

[0003] As a flow resistance element, the capillary tube is widely used due to its simple structure and good stability. However, the flow resistance of the capillary tube cannot be adjusted. Therefore, before use, the flow resistance of the capillary tube is usually measured to ensure the replenishment rate when the capillary tube is used to replenish the liquid refrigerant.

[0004] Related technologies usually use a flow resistance calculation method or a room temperature measurement method to determine the flow resistance of the capillary when a liquid refrigerant is flowing. There is an error between the flow resistance obtained by the flow resistance calculation method and the actual flow resistance of the capillary. Since the flow resistance of the capillary is different at different temperatures and when different types of media are flowing, and the temperature of the liquid refrigerant is usually low, there is also an error between the flow resistance measured by the room temperature measurement method and the flow resistance of the capillary when a liquid refrigerant with a lower temperature is flowing. Summary of the invention

[0005] The present application provides a capillary flow resistance measurement system and method, which are used to solve the problem in the related art that the flow resistance of the capillary is affected by the temperature and the type of refrigerant medium, and the flow resistance of the capillary when a liquid refrigerant with a relatively low circulation temperature is measured using a flow resistance calculation method or a room temperature measurement method, resulting in low measurement accuracy.

[0006] The present application provides a capillary flow resistance measurement system, the measurement system comprising a dewar, a liquid storage tank, a pump, a mass flow meter and a connecting pipeline, wherein:

[0007] The dewar has an inner cavity, the liquid storage tank is used to store liquid refrigerant, the liquid storage tank is connected to the inner cavity, the connecting pipeline is detachably connected to the dewar, the first port of the connecting pipeline extends into the inner cavity, the first port is used to connect to a capillary, the pump and the mass flow meter are both arranged in the connecting pipeline, and the pump and the mass flow meter are both located outside the dewar.

[0008] According to the measurement system provided by the present application, the measurement system further includes a gas storage tank, the gas storage tank is used to store gaseous refrigerant medium, and the gas storage tank is connected to the connecting pipeline;

[0009] The Dewar is provided with an exhaust structure, and the exhaust structure is used to exhaust the gas in the inner cavity.

[0010] According to the measurement system provided in the present application, the connecting pipeline includes a gas delivery pipe and a connecting pipe, the gas delivery pipe is detachably connected to the Dewar, one end of the gas delivery pipe is located in the inner cavity, and the port located in the inner cavity forms the first port, and the other end of the gas delivery pipe is connected to the gas storage tank;

[0011] The connecting pipe is connected to the gas pipe, and the connecting position between the connecting pipe and the gas pipe is located outside the Dewar, and the pump and the mass flow meter are arranged in the connecting pipe.

[0012] According to the measurement system provided in the present application, the gas delivery pipe and the Dewar are pluggable and connected, so that the gas delivery pipe is detachably connected to the Dewar, and the first port is used to be detachably connected to the capillary tube;

[0013] The connecting pipe and the gas delivery pipe are detachably connected.

[0014] According to the measurement system provided by the present application, the measurement system further includes a second valve and a second pressure detection mechanism, wherein the second valve and the second pressure detection mechanism are both provided in the gas transmission pipe and are both located between the communication position and the gas storage tank;

[0015] The measuring system further comprises a third valve and a third pressure detection mechanism, and the third valve and the third pressure detection mechanism are arranged in the connecting pipe.

[0016] According to the measurement system provided in the present application, the Dewar includes an inner layer and an outer layer, the outer layer is arranged around the inner layer, and a sandwich is formed between the inner layer and the outer layer, the sandwich is connected to the connecting pipeline through a vacuum tube so that the sandwich is connected to the inlet of the pump, and the vacuum tube is provided with a fourth valve.

[0017] According to the measurement system provided in the present application, the Dewar further includes a heat shield, which is disposed between the inner layer and the outer layer and surrounds the inner layer.

[0018] According to the measurement system provided in the present application, the measurement system includes an infusion tube, a first valve and a first pressure detection mechanism, the liquid storage tank and the inner cavity are connected through the infusion tube, and the first valve and the first pressure detection mechanism are arranged on the infusion tube.

[0019] According to the measurement system provided in the present application, the measurement system also includes a temperature detection mechanism, which is located in the inner cavity, and the distance between the temperature detection mechanism and the bottom wall of the Dewar is greater than or equal to the distance between the first port and the bottom wall of the Dewar.

[0020] The present application provides a method for measuring capillary flow resistance, which is applied to the measurement system described in claim 1 above, and the measurement method comprises:

[0021] installing the capillary tube at the first port;

[0022] placing the capillary tube in the lumen;

[0023] Opening the liquid storage tank, and introducing the liquid refrigerant into the inner cavity, so that the liquid refrigerant reaches a preset liquid level;

[0024] Turning on the pump and the mass flow meter, and reading a first reading of the mass flow meter;

[0025] Turn off the pump, the mass flow meter, and the fluid reservoir.

[0026] According to the measurement method provided in the present application, the measurement system further includes a gas storage tank, the gas storage tank is used to store gaseous refrigerant, the gas storage tank is connected to the connecting pipeline, and the dewar is provided with an exhaust structure, the exhaust structure is used to exhaust the gas in the inner cavity;

[0027] Wherein, after placing the capillary in the inner cavity and before opening the liquid storage tank, the measuring method further comprises:

[0028] The gas storage tank is opened, and a gaseous refrigerant medium is introduced into the capillary tube.

[0029] According to the measurement method provided by the present application, after installing the capillary at the first port, the measurement method further includes:

[0030] Opening the gas tank;

[0031] The outlet of the capillary is placed in the intermediate liquid, and whether bubbles overflow from the outlet of the capillary is observed. If bubbles overflow, the capillary is placed in the inner cavity.

[0032] According to the measurement method provided in the present application, the connecting pipeline includes a gas pipe and a connecting pipe, the gas pipe is detachably connected to the Dewar, one end of the gas pipe is located in the inner cavity, and the port located in the inner cavity forms the first port, and the other end of the gas pipe is connected to the gas storage tank;

[0033] The connecting pipe is connected to the gas pipe, and the connecting position between the connecting pipe and the gas pipe is located outside the Dewar, and the pump and the mass flow meter are arranged in the connecting pipe;

[0034] Wherein, after opening the liquid storage tank and introducing the liquid refrigerant into the inner cavity so that the liquid refrigerant reaches a preset liquid level, and before starting the pump, the measuring method further includes:

[0035] Close the gas tank.

[0036] According to the measurement method provided in the present application, the measurement system further includes a second valve and a second pressure detection mechanism, wherein the second valve and the second pressure detection mechanism are both provided in the gas pipeline and are both located between the communication position and the gas storage tank;

[0037] Wherein, in the process of opening the gas storage tank and introducing the gaseous refrigerant medium into the capillary tube, the opening of the second valve is adjusted to control the pressure in the gas pipeline within a second preset pressure range.

[0038] According to the measurement method provided by the present application, after reading the first indication of the mass flow meter, the measurement method further comprises: replacing the capillary tube,

[0039] Wherein, replacing the capillary comprises:

[0040] shutting down the pump;

[0041] Opening the gas storage tank, and introducing the gaseous refrigerant medium into the capillary tube;

[0042] removing the capillary tube from the inner cavity;

[0043] replacing the capillary connected to the first port;

[0044] The replaced capillary tube is placed in the inner cavity.

[0045] According to the measurement method provided by the present application, after shutting down the pump, the mass flow meter and the liquid storage tank, the measurement method further includes:

[0046] Opening the gas storage tank, and introducing the gaseous refrigerant into the capillary tube until the liquid refrigerant in the inner cavity is vaporized;

[0047] Close the gas tank.

[0048] According to the measurement method provided in the present application, the Dewar includes an inner layer and an outer layer, the outer layer is arranged around the inner layer, and a sandwich is formed between the inner layer and the outer layer, the sandwich is connected to the connecting pipeline through a vacuum tube, so that the sandwich is connected to the inlet of the pump, and the vacuum tube is provided with a fourth valve;

[0049] Wherein, before opening the liquid storage tank, the measuring method further comprises:

[0050] opening the fourth valve;

[0051] Turning on the pump until the interlayer is in a vacuum state;

[0052] Close the pump and the fourth valve.

[0053] According to the measurement method provided in the present application, after placing the capillary in the inner cavity and before opening the liquid storage tank, the flow resistance measurement method further includes:

[0054] Turning on the pump to extract the room-temperature gas in the inner cavity through the capillary tube;

[0055] Turning on the mass flow meter and reading a second indication of the mass flow meter;

[0056] Turn off the pump and the mass flow meter.

[0057] According to the measurement method provided in the present application, the measurement system further includes a temperature detection mechanism, the temperature detection mechanism is located in the inner cavity, and the distance between the temperature detection mechanism and the bottom wall of the Dewar is greater than or equal to the distance between the first port and the bottom wall of the Dewar;

[0058] Wherein, during the process of introducing the liquid refrigerant medium into the inner cavity, when the temperature detected by the temperature detection mechanism is less than or equal to a first preset temperature, the liquid storage tank is closed; when the temperature detected by the temperature detection mechanism is greater than or equal to a second preset temperature, the liquid storage tank is opened, and the second preset temperature is greater than the first preset temperature, so that the liquid refrigerant medium reaches a preset liquid level.

[0059] In the embodiment of the present application, the liquid refrigerant is filled into the dewar, the capillary is immersed in the liquid refrigerant, the liquid refrigerant in the capillary is extracted by a pump, the flow rate of the liquid refrigerant is measured by a mass flow meter, and a relatively accurate flow resistance of the capillary in the liquid refrigerant temperature zone is calculated by the flow rate of the liquid refrigerant. It can be seen that the present application can solve the problem in the related art that the flow resistance of the capillary is affected by the temperature and the type of refrigerant, and the flow resistance calculation method or the room temperature measurement method is used to measure the flow resistance of the capillary when the liquid refrigerant with a lower circulation temperature is low, and the measurement accuracy is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the present application or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0061] Figure 1 is a schematic diagram of the structure of the capillary flow resistance measurement system provided by the present application;

[0062] Figure 2 It is a schematic diagram of the structure of the Dewar provided by this application;

[0063] Figure 3 It is a flow chart of the method for measuring capillary flow resistance provided in this application.

[0064] Reference numerals:

[0065] 100-Dewar, 110-Inner cavity, 120-Inner layer, 130-Outer layer, 140-Heat shield, 150-End cover,

[0066] 200-liquid storage tank, 210-first switch valve,

[0067] 300-Pump,

[0068] 400-Mass flow meter,

[0069] 500-gas tank, 510-second switch valve,

[0070] 610-infusion tube, 620-gas tube, 630-connecting tube, 640-vacuum tube,

[0071] 710-first valve, 720-second valve, 730-third valve, 740-fourth valve,

[0072] 810-first pressure detection mechanism, 820-second pressure detection mechanism, 830-third pressure detection mechanism, 840-fourth pressure detection mechanism,

[0073] 900-Temperature detection mechanism,

[0074] 1000-capillary. DETAILED DESCRIPTION

[0075] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0076] Please refer to Figure 1 to Figure 2 The present application discloses a capillary flow resistance measurement system for measuring the flow resistance of a capillary. The flow resistance of a capillary refers to the ratio of the pressure difference in the capillary to the flow rate, R=△P / Q, where R refers to the flow resistance, △P refers to the pressure difference, and Q refers to the flow rate. The pressure difference in the present application is 1 bar. The magnitude of the flow resistance is related to the viscosity of the fluid, the length and radius of the capillary. The viscosity of the fluid is affected by the type and temperature of the fluid. That is to say, when different types of fluids flow in the capillary, or when the temperature of the capillary is different, the flow resistance of the capillary is different. The measurement system disclosed in the present application includes a dewar 100, a liquid storage tank 200, a pump 300, a mass flowmeter 400, and a connecting pipeline.

[0077] Among them, the Dewar 100 has an inner cavity 110, and the liquid storage tank 200 is used to store liquid refrigerant. The temperature of the liquid refrigerant is relatively low, and it is a low-temperature refrigerant, for example, liquid helium or liquid nitrogen. The liquid storage tank 200 is connected to the inner cavity 110, so that the liquid refrigerant is filled into the inner cavity 110. The connecting pipeline is detachably connected to the Dewar 100, and the first port of the connecting pipeline extends into the inner cavity 110. The first port of the connecting pipeline is used to connect the capillary 1000, and when the first port is connected to the capillary 1000, the connecting pipeline is connected to the capillary 1000. The pump 300 and the mass flowmeter 400 are both arranged in the connecting pipeline, so that the inner cavity 110, the capillary 1000, the connecting pipeline, the pump 300 and the mass flowmeter 400 form a passage, and the pump 300 and the mass flowmeter 400 are both located outside the Dewar 100.

[0078] Optionally, the pump 300 may be a mechanical dry pump or a molecular pump, and any brand of pump 300 (such as Agilent) may be used. Of course, the pump 300 may also use other types of pump bodies except for the oil pump. Optionally, the inlet of the pump 300 may be connected to the first port, and the mass flow meter 400 may be connected to the outlet of the pump 300.

[0079] When it is necessary to measure the flow resistance of the capillary 1000 in the liquid refrigerant temperature zone, the capillary 1000 is connected to the first port and placed in the inner cavity 110, and the liquid refrigerant is introduced into the inner cavity 110 through the liquid storage tank 200 until the capillary 1000 is immersed in the liquid refrigerant, and the pump 300 is turned on to extract the liquid refrigerant, and the liquid refrigerant enters the passage formed by the capillary 1000, the connecting pipeline, the pump 300 and the mass flow meter 400, and the reading of the mass flow meter 400 is observed. After the reading stabilizes, the first reading is recorded. The first reading is the flow rate of the liquid refrigerant of the capillary 1000 in the liquid refrigerant temperature zone. According to the flow rate of the liquid refrigerant, the flow resistance of the capillary 1000 is calculated. The specific calculation method is the existing technology and will not be repeated in this article.

[0080] It should be noted that different liquid refrigerants have different temperatures. For example, the temperature of liquid helium is about 4K, and the temperature of liquid nitrogen is about 77K. By filling the inner cavity 110 with different types of liquid refrigerants and allowing different types of liquid refrigerants to flow through the capillary 1000, the flow resistance of the capillary 1000 in different temperature zones can be measured. For example, when liquid helium is introduced into the inner cavity 110 and the capillary 1000 is immersed in liquid helium, the flow resistance of the capillary 1000 in the liquid helium temperature zone can be measured using the above-mentioned measurement system; when liquid nitrogen is introduced into the inner cavity 110 and the capillary 1000 is immersed in liquid nitrogen, the flow resistance of the capillary 1000 in the liquid nitrogen temperature zone can be measured using the above-mentioned measurement system.

[0081] When the measurement system of the present application is used to measure the flow resistance of the capillary 1000 when it is in the liquid refrigerant temperature zone and the liquid refrigerant is flowing therein, since the capillary 1000 is immersed in the liquid refrigerant and the liquid refrigerant is flowing therein, the temperature of the capillary 1000 is close to the temperature of the liquid refrigerant. Therefore, the accurate flow resistance of the capillary 1000 when it is in the liquid refrigerant temperature zone and the liquid refrigerant is flowing therein can be measured, thereby avoiding the calculation errors and measurement errors caused by the flow resistance calculation method and the room temperature measurement method in the related art.

[0082] In the embodiment of the present application, the liquid refrigerant is filled into the dewar 100, so that the capillary 1000 is immersed in the liquid refrigerant, and the liquid refrigerant in the capillary 1000 is extracted by the pump 300, so that the liquid refrigerant flows in the capillary 1000, and the temperature of the capillary 1000 is close to or the same as the liquid refrigerant, and the flow rate of the liquid refrigerant is measured by the mass flow meter 400, and the flow rate of the liquid refrigerant is calculated to obtain a more accurate flow resistance of the capillary 1000 when the liquid refrigerant flows and is in the liquid refrigerant temperature zone. It can be seen that the present application can solve the problem in the related art that the flow resistance of the capillary is affected by the temperature and the type of refrigerant, and the measurement accuracy is low when the flow resistance calculation method or the room temperature measurement method is used to measure the flow resistance of the capillary when the liquid refrigerant flows at a lower temperature.

[0083] Of course, the present application can also measure the flow resistance of the capillary 1000 in the normal temperature zone. When it is necessary to measure the flow resistance of the capillary 1000 in the normal temperature zone, the capillary 1000 is connected to the first port and placed in the inner cavity 110, and the pump 300 is turned on to extract the normal temperature gas (such as air) in the inner cavity 110. The flow rate of the normal temperature gas is recorded by the mass flow meter 400, and the flow resistance of the capillary 1000 in the normal temperature zone is calculated based on the flow rate of the normal temperature air.

[0084] In a further technical solution, the measurement system may further include a gas storage tank 500, which is used to store a gaseous refrigerant. The gas storage tank 500 is connected to a connecting pipeline so as to introduce the gaseous refrigerant into the capillary 1000 and the inner cavity 110 through the connecting pipeline. It should be noted that the liquid refrigerant stored in the liquid storage tank 200 and the gaseous refrigerant stored in the gas storage tank 500 in the present application may be the same refrigerant. For example, when liquid helium is stored in the liquid storage tank 200, the gas storage tank 500 may store liquid helium. 4 He gas. For another example, when liquid nitrogen is stored in the liquid storage tank 200 , nitrogen gas can be stored in the gas storage tank 500 .

[0085] The Dewar 100 is provided with an exhaust structure, which is used to exhaust the gas in the inner cavity 110. During the process of introducing gaseous refrigerant medium into the capillary 1000 and the inner cavity 110, the gaseous refrigerant medium will enter the inner cavity 110 through the capillary 1000. The exhaust structure can exhaust the gas in the inner cavity 110 to avoid the problem of safety accidents caused by excessive pressure in the inner cavity 110 during the process of introducing gaseous refrigerant medium into the capillary 1000, thereby improving the safety of the measurement system.

[0086] Optionally, the exhaust structure can be an exhaust hole arranged on the Dewar 100, and the exhaust hole connects the external environment of the Dewar 100 and the inner cavity 110. The exhaust structure can also be a safety valve arranged on the Dewar 100. When the pressure in the inner cavity 110 reaches a third preset pressure, the safety valve opens to connect the external environment of the Dewar 100 and the inner cavity 110.

[0087] In this case, by introducing gaseous refrigerant into the connecting pipeline through the gas storage tank 500, the gaseous refrigerant can also flow through the capillary 1000 connected to the first port and the inner cavity 110, and the air in the capillary 1000 and the inner cavity 110 can be discharged, so as to prevent the formation of a low-temperature environment in the inner cavity 110 after the liquid refrigerant is introduced into the inner cavity 110, because the liquid refrigerant is a low-temperature refrigerant with a low temperature, and the low-temperature environment causes the air inside the capillary 1000 to condense, thereby causing the capillary 1000 to be blocked and the inner wall of the inner cavity 110 to freeze.

[0088] Specifically, the connecting pipeline may include a gas pipe 620 and a connecting pipe 630. The gas pipe 620 can be detachably connected to the Dewar 100. One end of the gas pipe 620 can be located in the inner cavity 110, and the port of the gas pipe 620 located in the inner cavity 110 forms a first port. The other end of the gas pipe 620 can be connected to the gas storage tank 500.

[0089] The connecting pipe 630 can be connected to the gas pipe 620, and the pump 300 and the mass flow meter 400 can be arranged in the connecting pipe 630. In this case, the pump 300 and the mass flow meter 400 are arranged in the connecting pipe 630, and the connecting pipe 630 realizes the connection between the pump 300 and the mass flow meter 400 and the capillary 1000 through the connection with the gas pipe 620.

[0090] In an optional embodiment, the connecting position of the connecting pipe 630 and the gas pipe 620 can be located inside the dewar 100. In this structure, the gas pipe 620 and the connecting pipe 630 both need to pass through the dewar 100, so it is necessary to open a hole on the dewar 100 for the gas pipe 620 and the connecting pipe 630 to pass through.

[0091] In the embodiment of the present application, the connecting position of the connecting pipe 630 and the gas delivery pipe 620 can be located outside the dewar 100. In this case, the connecting position is located outside the dewar 100, and there is no need to open a hole on the dewar 100 for the connecting pipe 630 to pass through, thereby reducing the number of openings on the dewar 100, improving the structural strength of the dewar 100, and reducing the heat leakage of the dewar 100.

[0092] When the flow resistance of the capillary 1000 needs to be measured, the capillary 1000 needs to be placed in the inner cavity 110 of the Dewar 100. To this end, in an optional embodiment, the Dewar 100 may be provided with a shell and an end cap 150, and the end cap 150 may be detachably connected to the shell. After the end cap 150 and the shell are separated, the capillary 1000 is placed in the inner cavity 110, and then the end cap 150 and the shell are connected.

[0093] In another optional embodiment, the gas pipe 620 and the Dewar 100 can be connected in a pluggable manner so that the gas pipe 620 and the Dewar 100 can be detachably connected. Specifically, an opening can be set on the Dewar 100, and the capillary 1000 and the connecting pipeline can be extended into the inner cavity 110 through the opening, or part of the connecting pipeline and the capillary 1000 can be taken out of the inner cavity 110 through the opening, thereby realizing a pluggable connection between the gas pipe 620 and the Dewar 100.

[0094] The first port is used to be detachably connected to the capillary 1000. Optionally, the capillary 1000 can be connected to the first port by soldering. In this connection mode, heating can separate the capillary 1000 and the first port. For example, the connection position between the capillary 1000 and the first port can be reheated using a hot air gun or other tool to complete the separation of the capillary 1000 and the first port.

[0095] In this case, the pluggable connection makes it easy to place the capillary 1000 in the inner cavity 110 or take it out from the inner cavity 110. When the capillary 1000 to be tested needs to be replaced, the gas pipe 620 can be directly pulled out from the Dewar 100, which is simple and convenient to operate.

[0096] In order to facilitate the plugging and unplugging operation of the gas pipe 620, the connecting pipe 630 and the gas pipe 620 can be detachably connected, and disconnecting the connection between the connecting pipe 630 and the gas pipe 620 is more convenient for plugging and unplugging the gas pipe 620. Optionally, the connecting pipe 630 and the gas pipe 620 can be detachably connected by a ferrule connection. In the embodiment of the present application, the third valve 730 and the second pressure detection mechanism 820 (see below) can be connected by a ferrule to achieve a detachable connection between the connecting pipe 630 and the gas pipe 620. Of course, the connecting pipe 630 and the gas pipe 620 can also be connected by other pipeline connection methods, which are not limited in this article.

[0097] In a further technical solution, the measurement system may further include a second valve 720 and a second pressure detection mechanism 820, which may be both provided in the gas pipe 620 and both located between the connection position and the gas storage tank 500. The gas pipe 620 may further be provided with a second switch valve 510, which is a switch valve of the gas storage tank 500, and the opening and closing of the gas storage tank 500 are controlled by the opening and closing of the second switch valve 510. The gas pipe 620 may further be provided with a fourth pressure detection mechanism 840, which is used to measure the pressure of the gas storage tank 500.

[0098] In this case, the opening and closing of the gas storage tank 500 is controlled by the second switch valve 510, and the pressure in the gas pipe 620 is adjusted during the filling process of the gaseous refrigerant medium by adjusting the opening of the second valve 720. The gas transmission pressure is detected by the second pressure detection mechanism 820 to determine whether there is a positive pressure in the gas pipe 620, thereby ensuring a smooth gas transmission process.

[0099] Optionally, during the process of charging the gaseous refrigerant, the pressure in the gas delivery pipe 620 may be 2 bar to ensure a positive pressure in the gas delivery pipe 620. The second pressure detection mechanism 820 may be a pressure sensor.

[0100] The measurement system may further include a third valve 730 and a third pressure detection mechanism 830, and the third valve 730 and the third pressure detection mechanism 830 may be disposed in the connecting pipe 630. The third pressure detection mechanism 830 is used to detect the pressure of the connecting pipe 630. By adjusting the opening of the third valve 730, the pressure in the connecting pipe 630 may be controlled. For example, when the liquid refrigerant or room temperature gas in the inner cavity 110 is extracted by the pump 300, the third valve 730 may be adjusted to control the pressure in the connecting pipe 630 to be less than or equal to 1.4 bar.

[0101] The third valve 730 can control the conduction and blockage of the connecting pipe 630. When the pump 300 is turned on to extract the liquid refrigerant (or room temperature gas) in the inner cavity 110, the third valve 730 is opened to make the connecting pipe 630 conductive. During this process, the gas tank 500 (i.e., the second switch valve 510) and the second valve 720 can be closed to prevent the gaseous refrigerant in the gas tank 500 from entering the pump 300 and the mass flow meter 400 during the process of extracting the liquid refrigerant, thereby affecting the accuracy of measuring the flow resistance. When the gaseous refrigerant is introduced into the capillary 1000, the gas tank 500 (i.e., the second switch valve 510) and the second valve 720 are opened, and the third valve 730 can be closed to prevent the gaseous refrigerant from entering the connecting pipe 630 through the gas pipe 620 and then entering the atmosphere through the connecting pipe 630, thereby wasting the gaseous refrigerant.

[0102] In the above scheme, when measuring the flow resistance of the capillary 1000 in the temperature zone of the liquid refrigerant medium, it is necessary to fill the liquid refrigerant medium into the Dewar 100. In order to better store the liquid refrigerant medium in the inner cavity 110 and maintain the low temperature environment in the inner cavity 110, in the embodiment of the present application, the Dewar 100 may include an inner layer 120 and an outer layer 130. The outer layer 130 may be arranged around the inner layer 120, and a sandwich may be formed between the inner layer 120 and the outer layer 130. The sandwich may be connected to the connecting pipeline through the vacuum tube 640. The vacuum tube 640 is connected to the connecting tube 630, and thus connected to the pump 300, so that the sandwich is connected to the inlet of the pump 300. The vacuum tube 640 may be provided with a fourth valve 740.

[0103] In this case, the air in the interlayer can be extracted by pump 300 to make the interlayer in a vacuum state, thereby reducing the convective heat leakage of the Dewar 100, extending the maintenance time of the low-temperature environment in the Dewar 100, slowing down the vaporization rate of the liquid refrigerant in the Dewar 100, and facilitating the storage of the liquid refrigerant.

[0104] When the pump 300 is used to extract the air in the interlayer, the first valve 710 (see below), the first switch valve 210 (see below), the second switch valve 510, the second valve 720 and the third valve 730 can be closed; in the process of filling the gaseous refrigerant medium, the gas storage tank 500 is opened (that is, the second switch valve 510 and the second valve 720 are opened, and the fourth valve 740 and the third valve 730 can be closed to prevent the gaseous refrigerant from entering the vacuum tube 640 through the connecting pipeline, thereby entering the interlayer, resulting in waste of the gaseous refrigerant medium; in the process of using the pump 300 to extract the liquid refrigerant (or normal temperature gas) in the inner cavity 110, the fourth valve 740 can be closed.

[0105] In a further technical solution, the dewar 100 may further include a heat shield 140, which may be disposed between the inner layer 120 and the outer layer 130 and disposed around the inner layer 120. In this case, the provision of the heat shield 140 can reduce the radiation heat leakage of the dewar 100 and further slow down the vaporization speed of the liquid refrigerant in the dewar 100. Optionally, the heat shield 140 may be a cold shield.

[0106] The dewar 100 may also include an end cover 150, the inner layer 120, the outer layer 130 and the heat shield 140 may be welded to the end cover 150, the inner layer 120, the outer layer 130 and the end cover 150 form a sandwich, the heat shield 140 is located between the inner layer 120 and the outer layer 130, and the exhaust structure of the dewar 100 may also be arranged on the end cover 150. The height of the dewar 100 (the height direction of the dewar 100 is consistent with the vertical direction) may be greater than or equal to 400 mm. In order to reduce conduction heat leakage, the diameters of the gas pipe 620 and the liquid pipe 610 (see below) may be designed to be smaller, and the first port of the gas pipe 620 may be close to the bottom wall of the dewar 100, thereby extending the length of the gas pipe 620. In this way, the heat conduction of the gas pipe 620 can be reduced, thereby reducing conduction heat leakage.

[0107] In the above solution, the liquid storage tank 200 is connected to the inner cavity 110. Specifically, the measurement system may further include an infusion tube 610, a first valve 710, and a first pressure detection mechanism 810. The liquid storage tank 200 and the inner cavity 110 may be connected through the infusion tube 610. The first valve 710 and the first pressure detection mechanism 810 are both provided on the infusion tube 610. The infusion tube 610 may be provided with a first switch valve 210, and the first switch valve 210 controls the opening and closing of the liquid storage tank 200.

[0108] In this case, the tank flushing speed of the liquid refrigerant is determined by the indication of the first pressure detection mechanism 810, and the filling speed of the liquid refrigerant is adjusted by adjusting the opening of the first valve 710.

[0109] Optionally, during the process of filling the inner cavity 110 with liquid refrigerant, the liquid storage tank 200 (i.e., the first switch valve 210) and the first valve 710 are opened, and the gas storage tank 500 and the second valve 720 are opened to fill the gaseous refrigerant until the liquid refrigerant reaches a preset liquid level, and then the gas storage tank 500 and the second valve 720 are closed. In this case, before the capillary 1000 is completely immersed in the liquid refrigerant, the gas in the capillary 1000 can be kept as the gaseous refrigerant, so as to prevent the capillary 1000 and the connecting pipeline from having air inside, resulting in the temperature in the inner cavity 110 being reduced during the process of filling the liquid refrigerant, and causing the air to condense in the capillary 1000, resulting in the problem of clogging of the capillary 1000.

[0110] The measurement system may further include a temperature detection mechanism 900 . The temperature detection mechanism 900 may be located in the inner cavity 110 , and a distance between the temperature detection mechanism 900 and the bottom wall of the Dewar 100 may be greater than or equal to a distance between the first port and the bottom wall of the Dewar 100 .

[0111] In an optional embodiment, the temperature detection mechanism 900 may be disposed on the inner wall of the dewar 100. In another optional embodiment, the temperature detection mechanism 900 may be disposed on the portion of the connecting pipeline located in the inner cavity 110. In this structure, the positional relationship between the temperature detection mechanism 900 and the first port is fixed, so that after the capillary 1000 is connected to the first port, the positional relationship between the capillary 1000 and the temperature detection mechanism 900 is fixed, avoiding the problem of difficulty in controlling the positional relationship between the temperature detection mechanism 900 and the capillary 1000 during the process of placing the capillary 1000 into the inner cavity 110.

[0112] Optionally, the temperature detection mechanism 900 may be a thermometer. When the liquid refrigerant is liquid helium, the thermometer may be a silicon diode thermometer, a carbon resistance thermometer, or a ruthenium oxide thermometer. Of course, a suitable temperature detection mechanism 900 may be selected according to the temperature of the liquid refrigerant, and the present application does not limit the specific type of the temperature detection mechanism 900.

[0113] The vertical height of the temperature detection mechanism 900 is higher than the height of the capillary 1000. The temperature detected when the temperature detection mechanism 900 is in contact with the liquid refrigerant is different from the temperature detected when it is not in contact with the liquid refrigerant. Therefore, the liquid level of the liquid refrigerant can be judged by the temperature detected by the temperature detection mechanism 900, and it can be judged whether the liquid refrigerant submerges the capillary 1000.

[0114] For example, when the liquid refrigerant is liquid helium, when the temperature detected by the temperature detection mechanism 900 is around 4K, it means that the liquid level of the liquid refrigerant is flush with or higher than the temperature detection mechanism 900. Because the height of the temperature detection mechanism 900 is higher than the height of the capillary 1000, it means that the liquid refrigerant has submerged the capillary 1000. When the temperature detected by the temperature detection mechanism 900 is greater than 5K, it means that the liquid level of the liquid refrigerant is lower than the height of the temperature detection mechanism 900. At this time, the liquid refrigerant needs to be replenished.

[0115] Of course, in other embodiments, a liquid level gauge may be provided in the Dewar 100 to measure the liquid level of the liquid refrigerant in the inner cavity 110, so as to determine whether the liquid refrigerant submerges the capillary 1000. However, the volume and cost of the temperature detection mechanism 900 are usually smaller than the volume and cost of the liquid level gauge. Therefore, using the temperature detection mechanism 900 to determine whether the liquid refrigerant submerges the capillary 1000 can reduce the cost of the measurement system and save the internal space of the inner cavity 110.

[0116] The present application also discloses a method for measuring capillary flow resistance, which is applied to the above-mentioned measurement system, such as Figure 3 As shown, the disclosed measurement method includes:

[0117] S101, installing the capillary 1000 at the first port.

[0118] S102 , placing the capillary 1000 in the inner cavity 110 .

[0119] It should be noted that the order of steps S101 and S102 is not limited.

[0120] S103, opening the liquid storage tank 200, and introducing liquid refrigerant into the inner cavity 110, so that the liquid refrigerant reaches a preset liquid level, or in other words, the liquid level of the liquid refrigerant is higher than or equal to the preset liquid level.

[0121] The height of the preset liquid level in the vertical direction may be higher than the height of the capillary tube 1000 . When the liquid refrigerant reaches the preset liquid level, it indicates that the capillary tube 1000 is immersed in the liquid refrigerant.

[0122] S104 , start the pump 300 and the mass flow meter 400 , and read the first reading of the mass flow meter 400 .

[0123] It should be noted that after starting the pump 300 and the mass flow meter 400, the reading of the mass flow meter 400 is observed, and after the reading is stable, the first reading is recorded, which is the flow rate of the liquid refrigerant in the capillary 1000 in the liquid refrigerant temperature zone.

[0124] S105 , turning off the pump 300 , the mass flow meter 400 and the liquid storage tank 200 .

[0125] When it is necessary to measure the flow resistance of the capillary 1000 in the liquid refrigerant temperature zone, the first indication is measured according to the above steps. The first indication is the flow rate of the liquid refrigerant in the capillary 1000 in the liquid refrigerant temperature zone. The flow resistance of the capillary 1000 is calculated based on the flow rate of the liquid refrigerant. The specific calculation method is the existing technology and will not be repeated in this article.

[0126] When the measurement method of the present application is used to measure the flow resistance of the capillary 1000 in the liquid refrigerant temperature zone, since the capillary 1000 is immersed in the liquid refrigerant and the liquid refrigerant flows inside, the temperature of the capillary 1000 is close to the temperature of the liquid refrigerant. Therefore, a more accurate flow resistance of the capillary 1000 in the liquid refrigerant temperature zone can be measured, avoiding the problem of errors in measuring the flow resistance of the capillary 1000 in the liquid refrigerant temperature zone using the flow resistance calculation method and room temperature measurement method in the related technology.

[0127] In a further technical solution, the measurement system further includes a gas storage tank 500 , which is used to store gaseous refrigerant. The gas storage tank 500 is connected to a connecting pipeline. The Dewar 100 is provided with an exhaust structure, which is used to exhaust the gas in the inner cavity 110 .

[0128] Wherein, after the above step of placing the capillary 1000 in the inner cavity 110 and before the above step of opening the liquid storage tank 200, the measuring method may further include:

[0129] Step A1: Open the gas storage tank 500 and introduce gaseous refrigerant into the capillary tube 1000 .

[0130] In this case, before filling the inner cavity 110 with liquid refrigerant, first open the gas storage tank 500 to fill the capillary 1000 and the inner cavity 110 with gaseous refrigerant, and discharge the air in the capillary 1000 and the inner cavity 110, so as to avoid the problem that when the liquid refrigerant is subsequently filled into the inner cavity 110, the temperature in the inner cavity 110 decreases, causing the air on the inner wall of the capillary 1000 or the inner cavity 110 to condense into ice, thereby causing the capillary 1000 to be blocked.

[0131] Of course, in order to detect whether the capillary 1000 to be tested is unobstructed, after the above step of installing the capillary 1000 on the first port, the measuring method may further include:

[0132] Step B1: Open the gas storage tank 500 and introduce gaseous refrigerant into the capillary tube 1000 .

[0133] Step B2: Place the outlet of the capillary 1000 in the intermediate liquid and observe whether bubbles overflow from the outlet of the capillary 1000 . If bubbles overflow, place the capillary 1000 in the inner cavity 110 .

[0134] If no bubbles overflow from the outlet of the capillary 1000 , it indicates that the capillary 1000 is clogged and the capillary 1000 may be repaired or replaced.

[0135] The intermediate liquid can be alcohol or other liquid that does not react with the gaseous refrigerant. If bubbles overflow from the outlet of the capillary 1000 in the intermediate liquid, it means that the capillary 1000 is unobstructed and not blocked. Then the flow resistance of the capillary 1000 is measured.

[0136] In this case, not only can it be detected whether the capillary tube 1000 is unobstructed, but also dust and other impurities in the capillary tube 1000 can be cleaned by the gaseous refrigerant medium to keep the capillary tube unobstructed and clean.

[0137] It should be noted that the filling of the gaseous refrigerant medium into the inner cavity 110 can be maintained until the liquid refrigerant medium reaches a preset liquid level, so as to prevent air from being present inside the capillary 1000 and the connecting pipeline, resulting in the temperature in the inner cavity 110 decreasing during the filling of the liquid refrigerant medium, causing the air to condense in the capillary 1000 and causing blockage of the capillary 1000.

[0138] The connecting pipeline may include a gas pipe 620 and a connecting pipe 630. The gas pipe 620 and the Dewar 100 are detachably connected. One end of the gas pipe 620 may be located in the inner cavity 110, and the port of the gas pipe 620 located in the inner cavity 110 forms a first port. The other end of the gas pipe 620 may be connected to the gas storage tank 500.

[0139] The connecting pipe 630 may be connected to the gas supply pipe 620 , and the connecting position of the connecting pipe 630 and the gas supply pipe 620 may be located outside the Dewar 100 . The pump 300 and the mass flow meter 400 may be disposed in the connecting pipe 630 .

[0140] Among them, after the step of opening the liquid storage tank 200 and introducing the liquid refrigerant into the inner cavity 110 to make the liquid refrigerant reach a preset liquid level, and before the step of starting the pump 300, the flow resistance measurement method further includes:

[0141] Step C1: Close the gas storage tank 500.

[0142] In this case, it is prevented that the gaseous refrigerant in the gas storage tank 500 enters the pump 300 and the mass flow meter 400 during the process of extracting the liquid refrigerant, thereby affecting the accuracy of measuring the flow resistance.

[0143] In a further technical solution, the measurement system may further include a second valve 720 and a second pressure detection mechanism 820, both of which are provided on the gas delivery pipe 620 and are both located between the connection position and the gas storage tank 500. A second switch valve 510 may be provided on the gas delivery pipe 620, and the opening and closing of the gas storage tank 500 are controlled by the opening and closing of the second switch valve 510. When the second switch valve 510 is opened, the gas storage tank 500 is opened, and when the second switch valve 510 is closed, the gas storage tank 500 is closed.

[0144] In the process of opening the gas storage tank 500 and introducing the gaseous refrigerant medium into the capillary tube 1000, the pressure in the gas pipe 620 can be controlled within a second preset pressure range by adjusting the opening of the second valve 720, for example, the pressure in the gas pipe 620 can be about 2 bar.

[0145] In the above step C1, the second valve 720 is closed while the gas storage tank 500 is closed (ie, the second switch valve 510 is closed).

[0146] The measurement system may further include a third valve 730 and a third pressure detection mechanism 830 . The third valve 730 and the third pressure detection mechanism 830 may be disposed in the connecting pipe 630 .

[0147] In the above step S104, while the pump 300 is turned on, the third valve 730 is slowly opened so that the reading of the third pressure detection mechanism 830 is less than or equal to 1.4 bar.

[0148] After the step of reading the first reading of the mass flow meter 400 , the flow resistance measurement method may further include: replacing the capillary tube 1000 .

[0149] The steps of replacing the capillary 1000 may include:

[0150] Step D1: Turn off the pump 300.

[0151] In the above solution, the connecting pipe is provided with a third valve 730, so step D1 may also be: closing the third valve 730. In this way, there is no need to frequently open and close the pump 300.

[0152] Step D2: Open the gas storage tank 500 and introduce gaseous refrigerant into the capillary tube 1000 .

[0153] In step D2, while opening the gas storage tank 500, the second valve 720 is also opened, and by controlling the opening of the second valve 720, the indication of the second pressure detection mechanism 820 is controlled to be maintained at approximately 2 bar, ensuring that the pressure in the gas pipe 620 is positive.

[0154] Step D3: Take the capillary 1000 out of the inner cavity 110 .

[0155] The connecting pipeline and the Dewar 100 can be connected in a pluggable manner to achieve a detachable connection between the connecting pipeline and the Dewar 100. The Dewar 100 can be provided with an opening for the connecting pipeline and the capillary 1000 to pass through. In this way, it is only necessary to pull out the connecting pipeline located in the Dewar 100 and the capillary 1000 connected to the first port.

[0156] Step D4: Replace the capillary 1000 connected to the first port.

[0157] The capillary 1000 can be connected to the first port by soldering. The connection position between the capillary 1000 and the first port can be reheated using a hot air gun or other tool to complete the separation of the old capillary 1000 and the first port, and then a new capillary 1000 can be connected to the first port by soldering.

[0158] Step D5: placing the replaced capillary 1000 in the inner cavity 110 .

[0159] Then the above steps S103, S104, etc. may be repeated.

[0160] In this case, the flow resistance of different capillaries 1000 in the temperature zone of the liquid refrigerant can be measured.

[0161] The Dewar 100 may include an inner layer 120 and an outer layer 130. The outer layer 130 may be arranged around the inner layer 120, and a sandwich may be formed between the inner layer 120 and the outer layer 130. The sandwich may be connected to the connecting pipeline through the vacuum tube 640 so that the sandwich is connected to the inlet of the pump 300. The vacuum tube 640 may be provided with a fourth valve 740.

[0162] Before the step of opening the liquid storage tank 200, the measuring method may further include:

[0163] Step E1: Open the fourth valve 740 .

[0164] In step E1 , the first valve 710 , the first switching valve 210 , the second switching valve 510 , the second valve 720 , and the third valve 730 may be closed.

[0165] Step E2: Turn on the pump 300 until the interlayer is in a vacuum state.

[0166] Step E3: Close the pump 300 and the fourth valve 740 .

[0167] In this case, the convection heat leakage of the dewar 100 can be reduced, the low temperature environment maintenance time in the dewar 100 can be prolonged, and the vaporization speed of the liquid refrigerant in the dewar 100 can be slowed down, which is beneficial to the storage of the liquid refrigerant.

[0168] Of course, in other embodiments, step E1, step E2 and step E3 may also be performed before the above step of installing the capillary 1000 on the first port, or before the above step of placing the capillary 1000 in the inner cavity 110.

[0169] After the step of placing the capillary 1000 in the inner cavity 110 and before the step of opening the liquid storage tank 200, the measuring method may further include:

[0170] Step F1: Turn on the pump 300 to extract the room temperature gas in the inner cavity 110 through the capillary 1000;

[0171] Optionally, the normal temperature gas may be air. In this process, the third valve 730 may be opened, and the first valve 710, the first switch valve 210, the second switch valve 510, the second valve 720 and the fourth valve 740 may be closed at the same time.

[0172] Step F2: Turn on the mass flow meter 400 and read the second reading of the mass flow meter 400.

[0173] Step F3: Turn off the pump 300 and the mass flow meter 400.

[0174] Steps F1, F2, and F3 may also be performed before the above-mentioned step A1.

[0175] The flow resistance measurement system may further include a temperature detection mechanism 900, which is located in the inner cavity 110, and the distance between the temperature detection mechanism 900 and the bottom wall of the Dewar 100 is greater than or equal to the distance between the first port and the bottom wall of the Dewar 100. Optionally, the temperature detection mechanism 900 may be disposed on the inner wall of the Dewar 100, or on the portion of the connecting pipeline located in the inner cavity 110.

[0176] In the process of introducing the liquid refrigerant into the inner cavity 110, when the temperature detected by the temperature detection mechanism 900 is less than or equal to the first preset temperature, the liquid storage tank 200 (i.e., the first switch valve 210) and the first valve 710 are closed, and when the temperature detected by the temperature detection mechanism 900 is greater than or equal to the second preset temperature, the liquid storage tank 200 is opened (i.e., the first switch valve 210 is opened) and the first valve 710 is opened. The second preset temperature is greater than the first preset temperature.

[0177] It should be noted that the first preset temperature and the second preset temperature can be set according to the type of the liquid refrigerant. For example, when the liquid refrigerant is liquid helium, the first preset temperature can be 4K and the second preset temperature can be 5K.

[0178] After shutting down the pump 300, the mass flow meter 400 and the liquid storage tank 200, the measuring method may further include:

[0179] Step G1: Open the gas storage tank 500 and introduce gaseous refrigerant into the capillary tube 1000 until the liquid refrigerant in the inner cavity 110 is vaporized.

[0180] During step G1 , the second valve 720 is opened simultaneously.

[0181] In the above solution, the dewar 100 is provided with an exhaust port, through which it is possible to observe whether the liquid refrigerant in the inner cavity 110 is completely vaporized. Alternatively, an observation window may be provided at the bottom of the dewar 100, and the observation window may be a transparent structure, through which the interior of the inner cavity 110 is observed to determine whether the liquid refrigerant is completely vaporized.

[0182] Step G2: Close the gas storage tank 500.

[0183] When performing step G2, the second valve 720 is closed, and all valves of the measurement system are closed.

[0184] In this case, the temperature of the liquid refrigerant is relatively low, and the liquid refrigerant in the inner cavity 110 is closed after it is completely vaporized, thereby preventing external air from entering the inner cavity 110 and the capillary tube 1000 and condensing into ice, causing the capillary tube 1000 to be blocked.

[0185] After measuring the flow resistance of the capillary 1000 in the liquid refrigerant temperature zone using the measurement method in the present application, the capillary 1000 can be applied to low-temperature working environments, working environments between gas and liquid phases, and working environments with variable pressure.

[0186] It should be noted that the measurement system used in the method for measuring the capillary flow resistance has the same structure as the above-mentioned measurement system.

[0187] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A capillary flow resistance measurement system, characterized in that: The measuring system comprises a dewar (100), a liquid storage tank (200), a pump (300), a mass flow meter (400) and a connecting pipeline, wherein: The dewar (100) has an inner cavity (110), the liquid storage tank (200) is used to store liquid refrigerant, the liquid storage tank (200) is connected to the inner cavity (110), the connecting pipeline is detachably connected to the dewar (100), a first port of the connecting pipeline is located in the inner cavity (110), the first port is used to connect to a capillary tube (1000), the pump (300) and the mass flow meter (400) are both arranged in the connecting pipeline, and the pump (300) and the mass flow meter (400) are both located outside the dewar (100).

2. The measuring system according to claim 1, characterized in that The measurement system further comprises a gas storage tank (500), the gas storage tank (500) being used to store gaseous refrigerant, and the gas storage tank (500) being in communication with the communication pipeline; The Dewar (100) is provided with an exhaust structure, and the exhaust structure is used to exhaust the gas in the inner cavity (110).

3. The measuring system according to claim 2, characterized in that The connecting pipeline comprises an air delivery pipe (620) and a connecting pipe (630); the air delivery pipe (620) is detachably connected to the dewar (100); one end of the air delivery pipe (620) is located in the inner cavity (110), and a port located in the inner cavity (110) forms the first port; the other end of the air delivery pipe (620) is connected to the gas storage tank (500); The connecting pipe (630) is connected to the gas supply pipe (620), and the connecting position of the connecting pipe (630) and the gas supply pipe (620) is located outside the Dewar (100). The pump (300) and the mass flow meter (400) are arranged in the connecting pipe (630).

4. The measuring system according to claim 3, characterized in that The gas delivery pipe (620) and the dewar (100) are pluggable and connected, so that the gas delivery pipe (620) and the dewar (100) are detachably connected, and the first port is used to be detachably connected to the capillary tube (1000); The connecting pipe (630) and the gas delivery pipe (620) are detachably connected.

5. The measuring system according to claim 3, characterized in that The measurement system further comprises a second valve (720) and a second pressure detection mechanism (820), wherein the second valve (720) and the second pressure detection mechanism (820) are both arranged on the gas transmission pipe (620), and are both located between the communication position and the gas storage tank (500); The measurement system further comprises a third valve (730) and a third pressure detection mechanism (830), and the third valve (730) and the third pressure detection mechanism (830) are arranged in the connecting pipe (630).

6. The measuring system according to claim 1, characterized in that The Dewar (100) comprises an inner layer (120) and an outer layer (130), wherein the outer layer (130) is arranged around the inner layer (120), and an interlayer is formed between the inner layer (120) and the outer layer (130), wherein the interlayer is connected to the connecting pipeline via a vacuum tube (640) so that the interlayer is connected to the inlet of the pump (300), and the vacuum tube (640) is provided with a fourth valve (740).

7. The measuring system according to claim 6, characterized in that The dewar (100) further comprises a heat shield (140), wherein the heat shield (140) is disposed between the inner layer (120) and the outer layer (130) and is disposed around the inner layer (120).

8. The measuring system according to claim 1, characterized in that The measurement system comprises an infusion tube (610), a first valve (710) and a first pressure detection mechanism (810); the liquid storage tank (200) and the inner cavity (110) are connected via the infusion tube (610); and the first valve (710) and the first pressure detection mechanism (810) are arranged on the infusion tube (610).

9. The measuring system according to claim 1, characterized in that The measurement system further comprises a temperature detection mechanism (900), wherein the temperature detection mechanism (900) is located in the inner cavity (110), and the distance between the temperature detection mechanism (900) and the bottom wall of the Dewar (100) is greater than or equal to the distance between the first port and the bottom wall of the Dewar (100).

10. A method for measuring capillary flow resistance, characterized in that: Applied to the measurement system of claim 1, the measurement method comprises: Installing the capillary tube (1000) at the first port; placing the capillary tube (1000) in the inner cavity (110); Opening the liquid storage tank (200), and introducing the liquid refrigerant into the inner cavity (110) so that the liquid refrigerant reaches a preset liquid level; Turning on the pump (300) and the mass flow meter (400), and reading a first reading of the mass flow meter (400); The pump (300), the mass flow meter (400) and the liquid storage tank (200) are turned off.

11. The measuring method according to claim 10, characterized in that: The measurement system further comprises a gas storage tank (500), the gas storage tank (500) being used to store a gaseous refrigerant medium, the gas storage tank (500) being in communication with the connecting pipeline, the dewar (100) being provided with an exhaust structure, the exhaust structure being used to exhaust the gas in the inner cavity (110); Wherein, after placing the capillary tube (1000) in the inner cavity (110) and before opening the liquid storage tank (200), the measuring method further comprises: The gas storage tank (500) is opened, and a gaseous refrigerant medium is introduced into the capillary tube (1000).

12. The measuring method according to claim 11, characterized in that: After installing the capillary tube (1000) on the first port, the measuring method further comprises: Opening the gas storage tank (500); The outlet of the capillary (1000) is placed in the intermediate liquid, and it is observed whether bubbles overflow from the outlet of the capillary (1000). If bubbles overflow, the capillary (1000) is placed in the inner cavity (110).

13. The measuring method according to claim 11, characterized in that: The connecting pipeline comprises an air delivery pipe (620) and a connecting pipe (630); the air delivery pipe (620) is detachably connected to the dewar (100); one end of the air delivery pipe (620) is located in the inner cavity (110), and a port located in the inner cavity (110) forms the first port; the other end of the air delivery pipe (620) is connected to the gas storage tank (500); The connecting pipe (630) is connected to the gas supply pipe (620), and the connecting position of the connecting pipe (630) and the gas supply pipe (620) is located outside the Dewar (100), and the pump (300) and the mass flow meter (400) are arranged on the connecting pipe (630); Wherein, after the liquid storage tank (200) is opened and the liquid refrigerant is introduced into the inner cavity (110) so that the liquid refrigerant reaches a preset liquid level, and before the pump (300) is opened, the measuring method further comprises: Close the gas tank (500).

14. The measuring method according to claim 13, characterized in that: The measurement system further comprises a second valve (720) and a second pressure detection mechanism (820), wherein the second valve (720) and the second pressure detection mechanism (820) are both arranged on the gas transmission pipe (620), and are both located between the communication position and the gas storage tank (500); In the process of opening the gas storage tank (500) and introducing the gaseous refrigerant medium into the capillary tube (1000), the opening of the second valve (720) is adjusted to control the pressure in the gas pipe (620) to be within a second preset pressure range.

15. The measuring method according to claim 13, characterized in that: After reading the first indication of the mass flow meter (400), the measuring method further comprises: replacing the capillary tube (1000), Wherein, replacing the capillary tube (1000) comprises: Turning off the pump (300); Opening the gas storage tank (500) and introducing the gaseous refrigerant medium into the capillary tube (1000); Taking the capillary tube (1000) out of the inner cavity (110); replacing the capillary tube (1000) connected to the first port; The replaced capillary tube (1000) is placed in the inner cavity (110).

16. The measuring method according to claim 13, characterized in that: After shutting down the pump (300), the mass flow meter (400) and the liquid storage tank (200), the measuring method further comprises: Opening the gas storage tank (500) and introducing the gaseous refrigerant medium into the capillary tube (1000) until the liquid refrigerant medium in the inner cavity (110) is vaporized; Close the gas tank (500).

17. The measuring method according to claim 10, characterized in that: The dewar (100) comprises an inner layer (120) and an outer layer (130), wherein the outer layer (130) is arranged around the inner layer (120), and an interlayer is formed between the inner layer (120) and the outer layer (130), wherein the interlayer is connected to the connecting pipeline via a vacuum tube (640) so that the interlayer is connected to the inlet of the pump (300), and the vacuum tube (640) is provided with a fourth valve (740); Wherein, before opening the liquid storage tank (200), the measuring method further comprises: Opening the fourth valve (740); Turning on the pump (300) until the interlayer is in a vacuum state; The pump (300) and the fourth valve (740) are closed.

18. The measuring method according to claim 10, characterized in that: After placing the capillary tube (1000) in the inner cavity (110) and before opening the liquid storage tank (200), the measuring method further comprises: Turning on the pump (300) to extract the room-temperature gas in the inner cavity (110) through the capillary tube (1000); Turning on the mass flow meter (400) and reading a second reading of the mass flow meter (400); The pump (300) and the mass flow meter (400) are turned off.

19. The measuring method according to claim 10, characterized in that: The measurement system further comprises a temperature detection mechanism (900), wherein the temperature detection mechanism (900) is located in the inner cavity (110), and the distance between the temperature detection mechanism (900) and the bottom wall of the Dewar (100) is greater than or equal to the distance between the first port and the bottom wall of the Dewar (100); Wherein, during the process of introducing the liquid refrigerant into the inner cavity (110), when the temperature detected by the temperature detection mechanism (900) is less than or equal to a first preset temperature, the liquid storage tank (200) is closed; and when the temperature detected by the temperature detection mechanism (900) is greater than or equal to a second preset temperature, the liquid storage tank (200) is opened, and the second preset temperature is greater than the first preset temperature, so that the liquid refrigerant reaches a preset liquid level.

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