Helium liquefaction rate test system and test method

Abstract

The invention provides a helium liquefaction rate testing system and method. A first low-temperature transmission pipeline (1) is used for transmitting liquid helium in a main liquid helium Dewar (14) of a helium liquefier to be tested into an auxiliary Dewar (3); liquid helium entering the auxiliary Dewar (3) is converted into a gas-liquid phase equilibrium state through the liquid helium Dewar (3) and is converted into helium in a normal-temperature gas state through the second low-temperature transmission pipeline (6), and the normal-temperature gas flowmeter (11) is used for measuring the flow of the helium in the normal-temperature gas state. A superconductive liquid helium liquid level meter method which cannot be calibrated in China is converted into a normal-temperature gas flow meter method which can be calibrated, so that the helium liquefaction rate is derived according to a gas state equation, and the measurement precision, credibility and autonomy and controllability are improved.

Description

Technical Field

[0001] This application relates to the field of cryogenic refrigeration, and particularly to a helium liquefaction rate test system and a test method. Background Art

[0002] The strategic importance of helium resources has become increasingly prominent. Helium resources in China are quite scarce, with a very low content, great extraction difficulty and high cost. Most of the helium is imported, which has severely restricted the development of some cutting-edge science and technology fields in China. Helium liquefaction can significantly reduce transportation costs. The helium liquefaction device is the key core equipment for realizing helium liquefaction. The helium liquefaction rate is an important technical index for measuring the liquefaction performance of a helium liquefaction device.

[0003] The existing helium liquefaction rate test methods mainly include the superconducting liquid level method and the tank pressure method.

[0004] Superconducting liquid level method: Under the stable operating conditions of the liquefaction device, the height of the liquid helium level in the liquid helium dewar is measured by a superconducting liquid level gauge. According to the height of the liquid helium level, the corresponding table of the dewar liquid level height and the liquid helium volume is consulted to obtain the accumulated liquid helium volume. The difference between the liquid helium volume at the end time and the initial time is the liquid helium output during this period. The ratio of the liquid helium output to the time interval is the average helium liquefaction rate during this time interval. The advantages of the superconducting liquid level method are simplicity, directness and easy measurement. The relative disadvantages are as follows: (1) The water volume of the liquid helium dewar depends on the dewar design and manufacturing manufacturer, usually mostly foreign manufacturers; (2) The table of the dewar liquid level height and the liquid helium volume depends on the dewar design and manufacturing manufacturer, usually mostly foreign manufacturers; (3) The liquid helium superconducting liquid level gauge depends on the superconducting liquid level gauge design and manufacturing manufacturer, usually mostly foreign manufacturers, and it is almost impossible to be calibrated by a third-party legal metrology institution.

[0005] Tank pressure method: The state point is determined according to the directly measured helium pressure and temperature in the buffer tank. Using the gas state equation and the water volume of the buffer tank, the reduction amount of helium in the buffer tank at the end time and the initial time is derived. After deducting the increase amount of helium caused by the increase in the liquid helium dewar liquid level and converting it into liquid helium increment according to the density, it is the liquid helium output during this period. The advantages of the tank pressure method are that it is not complicated, relatively direct, relatively easy to measure and the pressure sensor and thermometer calibration are relatively easy. However, the helium liquefaction rate value calculated by the tank pressure method is less than the helium liquefaction rate value obtained by the superconducting liquid level gauge method and temperature correction is required to obtain the corresponding state point.

[0006] In addition, the existing helium gas recovery and purification system that forms a helium closed cycle has a relatively large floor area, complex operation, and since the high-pressure compressor unit, high-pressure cryogenic purifier and their pipelines are special equipment, third-party notification and special equipment use certificate handling procedures need to be carried out. In addition, liquid nitrogen consumption is required. Summary of the Invention

[0007] In view of this, it is necessary to provide a helium liquefaction rate test system and a test method that can not only achieve a closed continuous cycle of helium but also achieve the test of the helium liquefaction rate in view of the technical defects existing in the prior art.

[0008] To solve the above problems, the present application adopts the following technical solutions:

[0009] The present application provides a helium liquefaction rate test system, including: a first cryogenic transfer pipeline (1), an auxiliary Dewar (3), a second cryogenic transfer pipeline (6), and a normal temperature gas flowmeter (11), wherein:

[0010] The first cryogenic transfer pipeline (1) is connected to the helium liquefier to be tested, and the first cryogenic transfer pipeline (1) is used to transfer the liquid helium in the main liquid helium Dewar (14) of the helium liquefier to be tested into the auxiliary Dewar (3); the liquid helium entering the auxiliary Dewar (3) is converted into a gas-liquid equilibrium state through the liquid helium Dewar (3) and then into helium gas in a normal temperature gas state after passing through the second cryogenic transfer pipeline (6), and the normal temperature gas flowmeter (11) is used to measure the flow rate of the helium gas in the normal temperature gas state.

[0011] In some embodiments, a cryogenic regulating valve (2) is further included, and the cryogenic regulating valve (2) is arranged on the first cryogenic transfer pipeline (1), and the cryogenic regulating valve (2) is used to regulate the liquid helium flow rate between the main liquid helium Dewar (14) and the auxiliary Dewar (3).

[0012] In some embodiments, an electric heater (4) and a liquid helium level gauge (5) are arranged in the auxiliary Dewar (3), the electric heater (4) is used to heat the inside of the auxiliary Dewar (3) to control the gas-liquid equilibrium of the helium in the auxiliary Dewar (3), and the liquid helium level gauge (5) is used to display the position of the liquid helium.

[0013] In some embodiments, a vacuum electric heater (7) is further included, the vacuum electric heater (7) is arranged downstream of the auxiliary Dewar (3) and is connected to the second cryogenic transfer pipeline (6), and the vacuum electric heater (7) is used to heat the second cryogenic transfer pipeline (6) to reheat the cryogenic helium gas in the second cryogenic transfer pipeline (6) to room temperature.

[0014] In some embodiments, a vacuum electric heater controller (9) connected to the vacuum electric heater (7) and a temperature sensor (8) connected to the vacuum electric heater controller (9) are further included, and the vacuum electric heater controller (9) is used to control the heating power of the vacuum electric heater (7) according to the temperature of the temperature sensor (8).

[0015] In some of the embodiments, a one-way valve (13) is further included. The one-way valve (13) is connected to the normal temperature gas flow meter (11), and the one-way valve (13) is used to prevent the backflow of helium.

[0016] In some of the embodiments, a switch valve (12) and the one-way valve (13) are also included.

[0017] The present application also provides a method for testing a helium liquefaction rate testing system, comprising the following steps:

[0018] The first cryogenic transmission pipeline (1) transmits the liquid helium in the main liquid helium dewar (14) of the helium liquefier to be tested to the auxiliary dewar (3);

[0019] The liquid helium entering the auxiliary dewar (3) is converted into a gas-liquid phase equilibrium state by the liquid helium dewar (3) and then converted into helium in a normal temperature gas state after passing through the second low temperature transmission pipeline (6);

[0020] The normal temperature gas flow meter (11) measures the flow rate of helium in the normal temperature gas state.

[0021] This application adopts the above technical solution, and its beneficial effects are as follows:

[0022] The present application provides a helium liquefaction rate test system and a test method. The first cryogenic transmission pipeline (1) is used to transmit the liquid helium in the main liquid helium dewar (14) of the helium liquefier to be tested to the auxiliary dewar (3); the liquid helium entering the auxiliary dewar (3) is converted into a gas-liquid phase equilibrium state through the liquid helium dewar (3) and then converted into helium in a normal temperature gas state through the second cryogenic transmission pipeline (6); the normal temperature gas flowmeter (11) is used to measure the flow rate of the helium in the normal temperature gas state. The above test system and test method , converting the superconducting liquid helium level meter method that cannot be calibrated in China into a calibrated room temperature gas flow meter method, and then deriving the helium liquefaction rate based on the gas state equation, thereby improving the measurement accuracy, reliability and independent controllability; and allowing helium to undergo a complete temperature change from liquid helium temperature (4.2K) to room temperature (300K), which can realize both the closed continuous circulation of helium and the helium liquefaction rate test, and is particularly suitable for the helium liquefaction rate measurement of the helium liquefier after the transport tooling is dismantled and initialized at a remote gas field site before being incorporated into the actual industrial production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only 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.

[0024] Figure 1 Schematic structural diagram of the helium liquefaction rate test system provided by an embodiment of the present application. Detailed implementation manners

[0025] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, but should not be construed as limiting the present application.

[0026] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "horizontal", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application.

[0027] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0028] For the purpose of making the objectives, technical solutions and advantages of the present application more clearly understood, taking the multi-functional detection of atherosclerosis in blood vessels as an example, and in combination with the accompanying drawings and embodiments, the present application will be further described in detail below.

[0029] Please refer to Figure 1 , the schematic structural diagram of the helium liquefaction rate test system provided by an embodiment of the present application, includes: a first cryogenic transfer pipeline (1), an auxiliary Dewar (3), a second cryogenic transfer pipeline (6) and a normal temperature gas flowmeter (11). The specific implementation manners and connection relationships of each component will be described in detail below.

[0030] The first cryogenic transfer pipeline (1) is connected to the helium liquefier to be tested. The first cryogenic transfer pipeline (1) is used to transfer the liquid helium in the main liquid helium Dewar (14) of the helium liquefier to be tested into the auxiliary Dewar (3); the liquid helium entering the auxiliary Dewar (3) is converted into a gas-liquid equilibrium state through the liquid helium Dewar (3) and then into helium gas in a normal temperature gas state after passing through the second cryogenic transfer pipeline (6). The normal temperature gas flowmeter (11) is used to measure the flow rate of the helium gas in the normal temperature gas state, determine the state point in combination with the temperature and pressure, and then derive the helium liquefaction rate according to the gas state equation.

[0031] In this embodiment, it further includes a cryogenic regulating valve (2), and the cryogenic regulating valve (2) is arranged on the first cryogenic transmission pipeline (1), and the cryogenic regulating valve (2) is used to regulate the liquid helium flow rate between the main liquid helium dewar (14) and the auxiliary dewar (3).

[0032] In this embodiment, an electric heater (4) and a liquid helium level gauge (5) are arranged in the auxiliary dewar (3). The electric heater (4) is used to heat the inside of the auxiliary dewar (3) to control the gas-liquid phase equilibrium of helium in the auxiliary dewar (3), and the liquid helium level gauge (5) is used to display the position of the liquid helium.

[0033] In this embodiment, it further includes a vacuum electric heater (7). The vacuum electric heater (7) is arranged downstream of the auxiliary dewar (3) and is connected to the second cryogenic transmission pipeline (6). The vacuum electric heater (7) is used to heat the second cryogenic transmission pipeline (6) to reheat the cryogenic helium gas in the second cryogenic transmission pipeline (6) to room temperature.

[0034] In this embodiment, it further includes a vacuum electric heater controller (9) connected to the vacuum electric heater (7) and a temperature sensor (8) connected to the vacuum electric heater controller (9). The vacuum electric heater controller (9) is used to control the heating power of the vacuum electric heater (7) according to the temperature of the temperature sensor (8).

[0035] In this embodiment, it further includes a check valve (13). The check valve (13) is connected to the normal temperature gas flowmeter (11), and the check valve (13) is used to prevent the reflux of helium gas.

[0036] In this embodiment, it further includes a switching valve (12) of the check valve (13).

[0037] It can be understood that in the above helium liquefaction rate test system, helium is transformed from the initial liquid state (including helium passing through the first cryogenic transmission pipeline (1) and the cryogenic regulating valve (2)) into a gas-liquid phase equilibrium state (including helium in the auxiliary dewar (3), the electric heater (4) and the liquid helium level gauge (5)), and then into a normal temperature gas state (including helium passing through the normal temperature gas flowmeter (11), the check valve (13) and the switching valve (12)). It has experienced a temperature change from 4.2K to 300K, which is significantly different from the pressure change process from 0.1MPa to 15MPa (high-pressure process) or 0.1MPa to 5MPa (medium-pressure process) experienced in the helium gas recovery and compression system. It can not only achieve a closed-loop continuous cycle of helium, but also achieve the measurement of the helium liquefaction rate, and is particularly suitable for measuring the helium liquefaction rate before the helium liquefier is initialized after the removal and transportation tooling is completed at a remote gas field site and incorporated into the actual industrial production line.

[0038] The present application provides a helium liquefaction rate test system and a test method. The first cryogenic transmission pipeline (1) is used to transmit the liquid helium in the main liquid helium dewar (14) of the helium liquefier to be tested to the auxiliary dewar (3); the liquid helium entering the auxiliary dewar (3) is converted into a gas-liquid phase equilibrium state through the liquid helium dewar (3) and then converted into helium in a normal temperature gas state through the second cryogenic transmission pipeline (6); the normal temperature gas flowmeter (11) is used to measure the flow rate of the helium in the normal temperature gas state. The above test system and test method , converting the superconducting liquid helium level meter method that cannot be calibrated in China into a calibrated room temperature gas flow meter method, and then deriving the helium liquefaction rate based on the gas state equation, thereby improving the measurement accuracy, reliability and independent controllability; and allowing helium to undergo a complete temperature change from liquid helium temperature (4.2K) to room temperature (300K), which can realize both the closed continuous circulation of helium and the helium liquefaction rate test, and is particularly suitable for the helium liquefaction rate measurement of the helium liquefier after the transport tooling is dismantled and initialized at a remote gas field site before being incorporated into the actual industrial production line.

[0039] In addition, the helium liquefaction rate test system and test method provided in the present application have the advantages of small footprint, simple operation, no need to comply with third-party notification and special equipment use license application procedures, no need to consume liquid nitrogen and zero emissions.

[0040] It can be understood that the technical features of the above-described embodiments can be arbitrarily combined. In order to make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0041] The above are only preferred embodiments of the present application, and only specifically describe the technical principles of the present application. These descriptions are only for explaining the principles of the present application and cannot be interpreted as limiting the scope of protection of the present application in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other specific implementation methods of the present application that can be associated with the technicians in this field without creative work, should be included in the scope of protection of the present application.

Claims

1. A helium liquefaction rate testing system, characterized in that, Comprising: A first low-temperature transfer pipeline (1), an auxiliary Dewar (3), a second low-temperature transfer pipeline (6), and a normal-temperature gas flowmeter (11), wherein: The first low-temperature transfer pipeline (1) is connected to the helium liquefier to be tested, and the first low-temperature transfer pipeline (1) is used to transfer the liquid helium in the main liquid helium Dewar (14) of the helium liquefier to be tested into the auxiliary Dewar (3); the liquid helium entering the auxiliary Dewar (3) is converted into a gas-liquid equilibrium state by the liquid helium Dewar (3) and then into helium gas in a normal-temperature gas state after passing through the second low-temperature transfer pipeline (6), and the normal-temperature gas flowmeter (11) is used to measure the flow rate of the helium gas in the normal-temperature gas state.

2. The helium liquefaction rate testing system according to claim 1, wherein It further comprises a low-temperature regulating valve (2), the low-temperature regulating valve (2) is arranged on the first low-temperature transfer pipeline (1), and the low-temperature regulating valve (2) is used to regulate the liquid helium flow rate between the main liquid helium Dewar (14) and the auxiliary Dewar (3).

3. The helium liquefaction rate testing system according to claim 1, characterized in that, An electric heater (4) and a liquid helium level gauge (5) are arranged in the auxiliary Dewar (3), the electric heater (4) is used to heat the inside of the auxiliary Dewar (3) to control the gas-liquid equilibrium of the helium in the auxiliary Dewar (3), and the liquid helium level gauge (5) is used to display the position of the liquid helium.

4. The helium liquefaction rate testing system according to claim 1, wherein It further comprises a vacuum electric heater (7), the vacuum electric heater (7) is arranged downstream of the auxiliary Dewar (3) and is connected to the second low-temperature transfer pipeline (6), and the vacuum electric heater (7) is used to heat the second low-temperature transfer pipeline (6) so that the low-temperature helium gas in the second low-temperature transfer pipeline (6) is reheated to room temperature.

5. The helium liquefaction rate testing system according to claim 4, characterized in that, It further comprises a vacuum electric heater controller (9) connected to the vacuum electric heater (7), and a temperature sensor (8) connected to the vacuum electric heater controller (9), and the vacuum electric heater controller (9) is used to control the heating power of the vacuum electric heater (7) according to the temperature of the temperature sensor (8).

6. The helium liquefaction rate testing system according to claim 1, characterized in that, It further comprises a check valve (13), the check valve (13) is connected to the normal-temperature gas flowmeter (11), and the check valve (13) is used to prevent the reflux of helium gas.

7. The helium liquefaction rate testing system according to claim 6, characterized in that, It further comprises a switching valve (12) for the check valve (13).

8. A testing method for a helium liquefaction rate testing system as described in claim 1, characterized in that, Comprising the following steps: The first low-temperature transfer pipeline (1) transfers the liquid helium in the main liquid helium Dewar (14) of the helium liquefier to be tested into the auxiliary Dewar (3); The liquid helium entering the auxiliary Dewar (3) is converted into a gas-liquid equilibrium state by the liquid helium Dewar (3) and then into helium gas in a normal-temperature gas state after passing through the second low-temperature transfer pipeline (6); The normal-temperature gas flowmeter (11) measures the flow rate of the helium gas in the normal-temperature gas state.

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