JP2019178939A - Gas leak measurement method and airtightness test device - Google Patents

Abstract

To provide a gas leak measurement method of a gas insulation device, which uses a leak test by a pressure change, and an airtightness test device.SOLUTION: A gas leak measurement method executes: a measurement step of measuring the degree of vacuum in a vacuum chamber with an airtightness test device including the vacuum chamber in which a gas insulation electric device sealing an insulating gas inside is stored, and a vacuum pump for evacuating gas from the vacuum chamber; and a determination step of determining the leak of the insulating gas on the basis of measurement result of the measurement step after the evacuation by the vacuum pump.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas leak measurement method and an air tightness test apparatus.

  Conventionally, a leak test based on a pressure change is known as an airtight test method for testing whether or not a gas sealed in a highly airtight container is leaked. In addition, an airtightness determination device using a leak test based on a pressure change has been proposed as a lightning arrester airtightness test method. However, for gas-insulated equipment, a technique that uses a leak test based on a pressure change as a hermetic test method has not been known so far.

JP 2001-33345 A

  The problem to be solved by the present invention is to provide a gas leak measuring method and gas tightness test apparatus for gas insulated equipment using a leak test by pressure change.

  According to an embodiment of the present invention, there is provided a gas leak measurement method comprising: a vacuum chamber in which a gas-insulated electrical device that contains an insulating gas is housed; and a vacuum pump that evacuates the gas in the vacuum chamber. A measurement procedure for measuring the degree of vacuum in the inside, and a determination procedure for determining a gas leak of the insulating gas based on a measurement result of the measurement procedure after being evacuated by the vacuum pump.

It is an external view which shows an example of the vacuum chamber with which the airtight test apparatus of this embodiment is provided. It is a figure which shows an example of a structure of the airtight test apparatus of this embodiment. It is a figure which shows an example of a structure of the control apparatus of this embodiment. It is a flowchart (the 1) which shows an example of operation | movement of the airtight test apparatus of this embodiment. It is a flowchart (the 2) which shows an example of operation | movement of the airtight test apparatus of this embodiment.

  Hereinafter, an airtightness test apparatus according to an embodiment will be described with reference to the drawings. The airtightness test apparatus of embodiment is an apparatus which determines whether the gas is leaking from a gas insulated electrical apparatus.

<Embodiment>
FIG. 1 is an external view showing an example of a vacuum chamber 10 provided in the airtightness test apparatus 1 of the present embodiment. The vacuum chamber 10 includes a lid part CV and a box part BX. The box part BX houses the gas insulation device GH to be tested in the airtight test. The lid CV covers the opening of the box BX. The vacuum chamber 10 stores the gas insulating device GH in the box part BX and closes the lid part CV, thereby maintaining the airtightness inside the box part BX.

  The gas insulation device GH is a circuit breaker, disconnector, bus line, lightning arrester, instrument transformer in a container filled with an insulating gas such as sulfur hexafluoride (hereinafter simply referred to as “gas”). Storing work grounding devices, etc., and insulating them. In the gas insulating device GH, gas leakage may occur due to aging deterioration of the container or external factors. The hermetic test apparatus 1 determines whether or not the gas insulating device GH housed in the vacuum chamber 10 is leaking gas.

<Configuration of airtight test apparatus 1>
FIG. 2 is a diagram illustrating an example of the configuration of the airtightness test apparatus 1 of the present embodiment. As shown in FIG. 2, the airtight test apparatus 1 includes a vacuum chamber 10, a plurality of vacuum pumps (vacuum pumps 20a to 20c shown), a plurality of vacuum gauges (vacuum gauges 30a to 30c shown), and a plurality of valves. (Valves 40a to 40d shown), a mass spectrometer 50, a plurality of heat dryers (heat dryers 60a to 60c shown), an adsorbent 70, and a control device (not shown). For example, a mechanical booster pump is used for the vacuum pump 20a, and a turbo molecular pump for high vacuum exhaust is used for the vacuum pump 20b. In the following description, when the vacuum pumps 20a to 20c are not distinguished from each other, they are collectively referred to as a vacuum pump 20, and when the vacuum gauges 30a to 30c are not distinguished from each other, they are collectively referred to as a vacuum gauge 30. When not distinguishing 40a-40d from each other, they are collectively referred to as a valve 40, and when not distinguished from each other, the heating dryers 60a-60c are collectively referred to as a heating dryer 60. Moreover, the airtight test apparatus 1 includes a plurality of pipes (pipes p1 to p7 shown in the figure) that connect the vacuum chamber 10, the vacuum pump 20, the vacuum gauge 30, or the valve 40 to each other. In the following description, when the pipes p1 to p7 are not distinguished from each other, they are collectively referred to as a pipe p.

  The vacuum chamber 10 is connected to the vacuum pump 20 by a pipe p through a valve 40. The valve 40 communicates or blocks the space between the vacuum chamber 10 and the vacuum pump 20 by opening and closing. The vacuum pump 20 evacuates the vacuum chamber 10 (box part BX) by drawing a vacuum when all the valves 40 installed between the vacuum pump 20 and the vacuum chamber 10 are open. . The vacuum gauge 30 measures the degree of vacuum (hereinafter referred to as “vacuum degree”) at each location of the airtightness test apparatus 1. When the degree of vacuum is good, the pressure in the vacuum chamber 10 is low, and when the degree of vacuum is bad, the pressure is high. As the vacuum gauge 30, for example, a Pirani vacuum gauge or an ionization vacuum gauge is used. In the example shown in the drawing, among the vacuum gauges 30, a Pirani vacuum gauge is used for the vacuum gauge 30a and the vacuum gauge 30b, and an ionization vacuum gauge is used for the vacuum gauge 30c. As illustrated, the vacuum gauge 30 a is directly connected to the vacuum chamber 10 and measures the degree of vacuum in the vacuum chamber 10. The vacuum gauge 30b is connected to the vacuum chamber 10 via a pipe p1, a valve 40a, and a pipe p2, and measures the degree of vacuum in the vacuum chamber 10. The vacuum gauge 30c is connected via the pipe p4, the valve 40c, and the pipe p5, and measures the degree of vacuum in the vacuum chamber 10.

  In the present embodiment, the vacuum gauge 30b may have a configuration in which a Pirani vacuum gauge and a Penning vacuum gauge are used together. In this case, the vacuum gauge 30b can measure the pressure with higher accuracy than when only the Pirani vacuum gauge is used.

  As described above, in the vacuum gauge 30a, the vacuum gauge 30b, and the vacuum gauge 30c, the range of pressure that can be measured is different. Specifically, the vacuum gauge 30a measures a pressure in a high pressure range (for example, about several to several thousand [Pa]), and the vacuum gauge 30b has a low pressure range (for example, several to several tens [mPa]. ] And the vacuum gauge 30c measures a pressure in a low pressure range (for example, about several [nPa] to several [Pa]). In addition, when providing the vacuum gauge which can measure the pressure of the wide range from several [nPa] to several thousand [Pa], the airtight test apparatus 1 does not need to be provided with the several vacuum gauge 30. FIG. In this case, a vacuum gauge capable of measuring a wide range of pressures is provided at the position of the vacuum gauge 30a.

The mass spectrometer 50 ionizes the sample included in the mass spectrometer 50 with an ion source, and the vacuum chamber 10 is maintained in a vacuum degree in which the mean free process of the ions can be secured by the vacuum pump 20. m / z (a dimensionless amount obtained by dividing the mass of the ion by the unit of atomic mass and further dividing by the number of charges of the ion) and measuring the ion or molecule contained in the gas in the vacuum chamber 10 Measure the mass. In the present embodiment, sulfur hexafluoride (ie, SF ₆ ) gas is mainly used for the gas insulating device GH. Therefore, the mass spectrometer 50 includes sulfur hexafluoride ( That is, measure the amount of SF ₆ ), sulfur pentafluoride (ie, SF ₅ ), sulfur (ie, S), and fluorine (ie, F) and based on their total amount or the amount of gas of each component Then, the amount of gas contained in the gas in the vacuum chamber 10 is measured.

  The heat dryer 60 is installed in contact with the surfaces of the plurality of pipes p (the pipes p1 and the pipes p4 to p5). Specifically, the heating dryer 60a is installed in contact with the surface of the piping p1, the heating dryer 60b is installed in contact with the surface of the piping p4, and the heating dryer 60c is in contact with the surface of the piping p5. Installed. The heating dryer 60 heats the inside of the vacuum chamber 10 through the installed pipe p, and removes impurities adhering to the inner wall of the vacuum chamber 10 and moisture in the pipe p and the vacuum chamber 10. In the present embodiment, the heating / drying device 60 always performs measurement by the pipe p1 and the pipe p4 connected to the space of the vacuum chamber 10, the vacuum gauge 30c, and the mass spectrometer 50 regardless of whether the valve is opened or closed. At this time, it is installed in the pipe p5 connected to the space in the vacuum chamber 10. The adsorbent 70 is, for example, silica gel or zeolite, and adsorbs moisture in the vacuum chamber 10. The adsorbent 70 is installed in the vacuum chamber 10 together with the gas insulating device GH or before the gas insulating device GH is stored in the vacuum chamber 10. The heating dryer 60 and the adsorbent 70 can remove the moisture of the gas in the vacuum chamber 10 and increase the measurement accuracy when the mass spectrometer 50 measures the gas in the gas insulating device GH. In addition, the heat dryer 60 may be installed in the vicinity of the pipe p in addition to being installed in contact with the pipe p.

  Each configuration provided in the airtightness test apparatus 1 includes a “Pirani vacuum gauge measurement mode” in which gas leakage of the gas insulating device GH housed in the vacuum chamber 10 is measured by a Pirani vacuum gauge (that is, vacuum gauges 30a to 30b). The “Pirani vacuum gauge measurement mode”, “ionization” by the “ionization vacuum gauge measurement mode” measured by the ionization vacuum gauge (that is, the vacuum gauge 30c) and the “mass spectrometer measurement mode” measured by the mass spectrometer 50 It operates in the order of “vacuum gauge measurement mode” and “mass spectrometer measurement mode”.

  In the illustrated example, the configuration used in the “Pirani vacuum gauge measurement mode” in the hermetic test apparatus 1 includes pipes p1 to p3, vacuum pumps 20a to 20b, vacuum gauges 30a to 30b, and valves 40a to 40b. It is. In the airtightness test apparatus 1, the configurations used in the “ionization vacuum gauge measurement mode” are the pipes p4 to p6, the vacuum pump 20c, the vacuum gauge 30c, and the valve 40c. The configuration used in the “mass spectrometer measurement mode” in the airtightness test apparatus 1 is a mass spectrometer 50.

  Here, the inside of the vacuum chamber 10 is roughly drawn by the configuration used in the “Pirani vacuum gauge measurement mode”, and is finally drawn in the “chamber vacuum mode” before shifting to the “ionization vacuum gauge measurement mode”. The configuration used in the “chamber vacuum mode” in the hermetic test apparatus 1 is pipes p1, p2, and p7, a vacuum pump 20b, and valves 40a and 40d.

  The start and stop of the operation of the vacuum pump 20 and the opening and closing of the valve 40 are controlled by a control device (not shown).

<Connection of the airtightness test apparatus 1>
The configuration used in the “Pirani vacuum gauge measurement mode” is connected from the vacuum chamber 10 in the order of the pipe p1, the valve 40a, the pipe p2, the valve 40b, the pipe p3, and the vacuum pump 20a. The configuration used in the “chamber vacuum mode” is connected in the order of the pipe p2, the valve 40d, the pipe p7, and the vacuum pump 20b. The configuration used in the “ionization vacuum gauge measurement mode” is connected from the vacuum chamber 10 in order of the pipe p4, the valve 40c, the pipe p5, the mass spectrometer 50, the pipe p6, and the vacuum pump 20c. The configurations used in the “mass spectrometer measurement mode” are the valve 40 c and the mass spectrometer 50 among the configurations described above.

<Configuration of Control Device 100>
FIG. 3 is a diagram illustrating an example of the configuration of the control device 100 of the present embodiment. The control device 100 includes, for example, an acquisition unit 102, a valve control unit 104, a vacuum pump control unit 106, and a determination unit 108 when a hardware processor such as a CPU (Central Processing Unit) executes a program (software). Each function part is realized. Some or all of these components are hardware (circuitry) such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), and GPU (Graphics Processing Unit). Part (including circuit)), or may be realized by cooperation of software and hardware.

  The acquisition unit 102 acquires information indicating the degree of vacuum of the vacuum chamber 10 measured by the vacuum gauge 30 for each vacuum gauge 30. The acquisition unit 102 acquires information indicating the amount of gas in the vacuum chamber 10 measured by the mass spectrometer 50. The acquisition unit 102 acquires various information, for example, constantly or at predetermined time intervals. The valve control unit 104 controls the opening and closing of the valve 40 for each valve 40. The vacuum pump control unit 106 controls the start and stop of the operation of the vacuum pump 20 for each vacuum pump 20. The determination unit 108 uses at least one of the information indicating the degree of vacuum of the vacuum chamber 10 acquired by the acquisition unit 102 and the information indicating the amount of gas in the vacuum chamber 10 to leak gas from the gas insulating device GH. It is determined whether or not.

<Operation of the airtightness test apparatus 1>
Hereinafter, details of the operation of the airtightness test apparatus 1 will be described with reference to FIGS. FIG. 4 is a flowchart (part 1) illustrating an example of the operation of the airtightness test apparatus 1 of the present embodiment. FIG. 5 is a flowchart (part 2) illustrating an example of the operation of the airtightness test apparatus 1 of the present embodiment. First, the valve control unit 104 controls the state of the valve 40 to the “Pirani gauge measurement mode” (step S100). Specifically, the valve control unit 104 controls the valves 40a to 40b to an open state and controls the other valves 40 to a closed state. Next, the vacuum pump controller 106 roughens the inside of the vacuum chamber 10 by the vacuum pump 20a (step S102). Next, the air tightness test apparatus 1 tests whether or not the gas insulation apparatus GH is leaking gas by a leak test due to a pressure change in a state where the inside of the vacuum chamber 10 is roughed. That is, the air tightness test apparatus 1 is left for a predetermined time (hereinafter, build-up) in a state where the vacuum chamber 10 is roughed (step S104).

  The determination unit 108 acquires information indicating the degree of vacuum in the vacuum chamber 10 measured by the vacuum gauge 30a after the build-up is completed from the acquisition unit 102, and the acquired measurement result of the vacuum gauge 30a is a predetermined threshold value (hereinafter referred to as a “threshold”). It is determined whether or not the threshold value TH1) is not more than (step S106). The threshold value TH1 is, for example, a value indicating a pressure of about 100 [Pa]. When the measurement result of the vacuum gauge 30a is larger than the threshold value TH1 (that is, when the degree of vacuum in the vacuum chamber 10 is poor), the determination unit 108 determines that gas has leaked from the gas insulating device GH (step S108). As described above, the vacuum gauge 30 a measures a pressure in a high pressure range as compared with the other vacuum gauges 30. Therefore, when it is determined that the gas insulating device GH is leaking gas based on the measurement result of the vacuum gauge 30a, a large amount of gas is leaking from the gas insulating device GH (large leak). When the determination unit 108 determines that the gas insulating device GH is leaking gas, the air tightness test apparatus 1 notifies the gas leak (step S110). The airtight test apparatus 1 includes, for example, a lamp that notifies that gas is leaking, and notifies the gas leak by turning on the lamp. In addition to the lamp, the air tightness test apparatus 1 may notify the gas leak by a buzzer, may notify the gas leak by a display, and the gas to be tested is connected to the information collecting apparatus connected via the network. You may notify gas leak by transmitting the information which shows that the insulation apparatus GH is leaking gas. The airtightness test apparatus 1 advances a process to step S132 after step S110. Details of step S132 will be described later.

  When the measurement result of the vacuum gauge 30a is equal to or less than the threshold value TH1 (that is, when the degree of vacuum in the vacuum chamber 10 is good), the determination unit 108 determines whether the vacuum gauge 30b measures the vacuum chamber 10 after the build-up is completed. Information indicating the degree of vacuum is acquired from the acquisition unit 102, and it is determined whether or not the acquired measurement result of the vacuum gauge 30b is equal to or less than a predetermined threshold (hereinafter, threshold TH2) (step S112). The threshold value TH2 is a value indicating a pressure of about 20 [Pa], for example. When the measurement result of the vacuum gauge 30b is larger than the threshold value TH2 (that is, when the degree of vacuum in the vacuum chamber 10 is poor), the determination unit 108 determines that gas has leaked from the gas insulating device GH (step S114). As described above, the vacuum gauge 30b measures the pressure in the low pressure range as compared with the other vacuum gauges 30a. Therefore, when it is determined that the gas insulating device GH is leaking gas based on the measurement result of the vacuum gauge 30b, only a small amount of gas leaks (small leak) from the gas insulating device GH. When the determination unit 108 determines that the gas insulating device GH is leaking gas (step S114), the airtight test apparatus 1 advances the process to step S110.

  Next, the valve control unit 104 controls the valve 40 to “chamber vacuum mode” (step S116). Specifically, the valve control unit 104 controls the valve 40a and the valve 40d to be in an open state, and controls the other valves 40 to be in a closed state. Next, the vacuum pump controller 106 pulls the inside of the vacuum chamber 10 by the vacuum pump 20b (step S118). Next, build-up is performed in a state where the inside of the vacuum chamber 10 is fully pulled (step S120).

  Next, the valve control unit 104 controls the valve 40 to the “ionization vacuum gauge measurement mode” (step S122). Specifically, the valve control unit 104 controls the valve 40c to an open state and controls the other valves 40 to a closed state. Next, the determination unit 108 acquires information indicating the degree of vacuum in the vacuum chamber 10 measured by the vacuum gauge 30c after the valve 40c is controlled to be open from the acquisition unit 102, and the measurement result of the acquired vacuum gauge 30c. Is a predetermined threshold (hereinafter referred to as threshold TH3 or less (step S124). The threshold TH3 is, for example, a value indicating a pressure of about 0.03 [Pa]. When the measurement result of the vacuum gauge 30c is larger than the threshold value TH3 (that is, when the degree of vacuum in the vacuum chamber 10 is poor (S124; NO)), it is determined that gas is leaking from the gas insulating device GH (step S125). As described above, the vacuum gauge 30c measures a pressure in a lower pressure range than the other vacuum gauges 30. Therefore, based on the measurement result of the vacuum gauge 30c, the gas insulating device GH is measured. When it is determined that gas has leaked, only a small amount of gas has leaked (small leak) from the gas insulation device GH The gas tightness test apparatus 1 causes the gas insulation device GH to leak through the determination unit 108. If it is determined (step S125) that the process proceeds to step S110, the determination unit 108 determines that the measurement result of the vacuum gauge 30c is equal to or lower than the threshold TH3 (that is, the degree of vacuum in the vacuum chamber 10 is good). If yes (S124; YES), the process proceeds to step S126.

  The threshold value TH3 is a value indicating a gas pressure that can flow into the mass spectrometer 50 (that is, the mass spectrometer 50 can measure) in addition to a value indicating a pressure of about 0.03 [Pa]. It may be. In this case, the determination unit 108 determines that there is a gas leak when the measurement result of the vacuum gauge 30c is larger than the threshold value TH3 (that is, when there is a gas leak that cannot be measured by the mass spectrometer 50). In addition, the mass spectrometer 50 can be prevented from malfunctioning.

Next, the control device 100 executes the “mass spectrometer measurement mode”. Specifically, the determination unit 108 determines the gas to be measured (that is, the gas) contained in the gas in the vacuum chamber 10 based on the measurement result measured by the mass spectrometer 50 during the main pulling in step S118. It is determined whether or not the amount of gas sealed in the insulating device GH is equal to or greater than a predetermined threshold (hereinafter, threshold TH4) (step S126). The threshold value TH4 is a value indicating an amount of about 0.00004 [Pa · m ³ / sec], for example. The determination unit 108 determines that gas is leaking from the gas insulating device GH when the amount of gas to be measured is equal to or greater than the threshold value TH4 (step S128). When it is determined that the gas insulating device GH is leaking gas based on the measurement result of the mass spectrometer 50, a small amount of gas is leaking from the gas insulating device GH (micro leak). When the determination unit 108 determines that the gas insulating device GH is leaking gas (step S128), the airtight test apparatus 1 advances the process to step S110.

  Next, when the determination unit 108 determines that the amount of gas to be measured is less than the threshold value TH4 (that is, it is determined that no gas has leaked), the gas tightness test apparatus 1 has no gas leak. Is notified (step S130). The airtightness test apparatus 1 notifies that there is no gas leak, for example, by turning off a lamp that notifies that gas leaks. In addition to the lamp, the gas tightness test apparatus 1 may notify that there is no gas leak by the display, and the gas insulation apparatus GH to be tested leaks into the information collecting apparatus connected via the network. It may be notified that no gas leaks by transmitting information indicating that the gas has not leaked.

  Next, the airtight test apparatus 1 ends the test for the gas insulating device GH (step S132). Specifically, the valve control unit 104 controls the valve 40h to be in an open state, makes the inside of the vacuum chamber 10 communicate with the outside air, and matches the atmospheric pressure in the vacuum chamber 10 with the atmospheric pressure.

<Summary of Embodiment>
As described above, the air tightness test apparatus 1 according to the present embodiment includes the vacuum chamber 10 in which the gas insulating device GH enclosing the insulating gas is housed, the vacuum pump 20 that evacuates the gas in the vacuum chamber 10, and the vacuum Based on the measurement result (vacuum gauge 30 in this example) for measuring the degree of vacuum in the chamber 10 and the measurement result of the vacuum gauge 30 after being evacuated by the vacuum pump 20, the gas leakage of the insulating gas is determined. And a determination unit 108 that can determine a gas leak of the gas insulating device GH using a leak test based on a pressure change.

  The airtightness test apparatus 1 of the present embodiment further includes a mass spectrometer 50 that measures the mass number of the substance in the vacuum chamber 10, and measures the mass of the substance in the vacuum chamber 10 by the mass spectrometer 50. Based on the measurement result of the mass spectrometer 50 after being evacuated by the vacuum pump 20, it is possible to determine the gas leakage of the insulating gas and to determine the gas leakage of the gas insulating device GH with higher accuracy.

  In addition, the airtightness test apparatus 1 of the present embodiment further includes a heating / drying device 60 that is installed in contact with or near the surface of the pipe p connecting the vacuum chamber 10 and the vacuum pump 20. When the air in the vacuum chamber 10 is evacuated by 20, the air in the vacuum chamber 10 is heated, and the measurement accuracy when the mass spectrometer 50 measures the gas in the gas insulating device GH can be improved. it can.

  Moreover, the airtightness test apparatus 1 of this embodiment can improve the measurement accuracy when the adsorbent 70 is installed in the vacuum chamber 10 and the mass spectrometer 50 measures the gas in the gas insulation apparatus GH. it can.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and appropriate modifications may be made without departing from the spirit of the present invention. it can. You may combine the structure as described in each embodiment mentioned above.

DESCRIPTION OF SYMBOLS 1 ... Airtight test apparatus, 10 ... Vacuum chamber, 20, 20a, 20b, 20c ... Vacuum pump, 30, 30a, 30b, 30c ... Vacuum gauge, 40, 40a, 40b, 40c, 40d, 40h ... Valve, 50 ... Mass Analyzer 60, 60a, 60b, 60c ... Heat dryer, 70 ... Adsorbent, 100 ... Control device, 102 ... Acquisition unit, 104 ... Valve control unit, 106 ... Vacuum pump control unit, 108 ... Determination unit, GH ... Gas insulation equipment, p, p1, p2, p3, p4, p5, p6, p7 ... piping

Claims (5)

An air tightness test apparatus comprising: a vacuum chamber in which a gas-insulated electrical device that encloses an insulating gas is housed; and a vacuum pump that evacuates the gas in the vacuum chamber
A measurement procedure for measuring the degree of vacuum in the vacuum chamber;
A determination procedure for determining gas leakage of the insulating gas based on the measurement result of the measurement procedure after being evacuated by the vacuum pump;
Perform gas leak measurement method. The gas tightness test apparatus further includes a mass spectrometer for measuring the mass number of the substance in the vacuum chamber,
The airtightness test apparatus is
Further executing a mass measurement procedure for measuring the mass of the substance in the vacuum chamber by the mass spectrometer;
In the determination procedure, based on the measurement result of the mass measurement procedure after being evacuated by the vacuum pump, the leakage of the insulating gas is determined.
The gas leak measuring method according to claim 1. The airtightness test apparatus further includes a heat dryer installed in contact with or near the surface of a pipe connecting the vacuum chamber and the vacuum pump,
The airtightness test apparatus is
When the air in the vacuum chamber is evacuated by the vacuum pump using the heat dryer, a heating procedure for heating the air in the vacuum chamber is executed.
The gas leak measuring method according to claim 1 or 2. A gas leakage measurement method performed using an airtight test apparatus including a vacuum chamber in which a gas-insulated electric device for sealing an insulating gas is housed, and a vacuum pump for evacuating the gas in the vacuum chamber,
A storage procedure in which an adsorbent that adsorbs moisture before being vacuumed by the vacuum pump is stored in the vacuum chamber;
A measurement procedure for measuring the degree of vacuum in the vacuum chamber;
A determination procedure for determining gas leakage of the insulating gas based on the measurement result of the measurement procedure after being evacuated by the vacuum pump;
A gas leak measurement method comprising: A vacuum chamber in which gas-insulated electrical equipment for enclosing insulating gas is stored;
A vacuum pump for evacuating the gas in the vacuum chamber;
A measuring unit for measuring the degree of vacuum in the vacuum chamber;
Based on the measurement result of the measurement unit after being evacuated by the vacuum pump, a determination unit that determines gas leakage of the insulating gas;
An air tightness test apparatus comprising:

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