Pressure-resistance leakage inspection method for valve and pressure-resistance leakage inspection device for valve

Abstract

To provide a pressure-resistance leakage inspection method for valve and pressure-resistance leakage inspection device for valve which can perform a high-precision leakage inspection while suppressing a facility cost for automation.SOLUTION: A pressure-resistance leakage inspection device 1 for valve includes: a calibration gas supply unit 40 which supplies calibration gas G2 into a chamber 10 by making a hydrogen concentration lower than a hydrogen concentration of inspection gas G1 so as to be almost equal to the atmosphere of hydrogen in the chamber 10 supplied with the calibration gas G2 at a supply flow rate for quality assurance and greater than the supply flow rate for quality assurance; and a leakage inspection pass / fail determination processing unit 51a which performs pass / fail determination processing of a leakage inspection on the basis of detection data following the time course of hydrogen by a gas sensor 30 of the calibration gas G2 supplied into the chamber 10.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a valve pressure leak inspection method and a valve pressure leak inspection device, and more particularly to a valve pressure leak inspection method and valve pressure leak inspection device that perform leak inspection by detecting hydrogen leaking from a valve housed in a chamber using a gas sensor. [Background technology]

[0002] Conventionally, valves are required to have high pressure resistance, and therefore, during manufacture, pressure tests are conducted to check the strength of pressure-resistant parts and whether or not there are any leaks. Methods for this pressure resistance test include, for example, a water immersion method, a sniffer method, and a vacuum chamber method. The submersion method is a method for detecting leaks by immersing a test object, the inside of which is pressurized with gas, in water and visually checking for bubbles that escape from inside the test object. The sniffer method is a method in which a search gas is filled inside an object to be inspected, and a probe is brought close to the gas that has flowed out from inside the object to be inspected, and the leak is detected by the probe. The vacuum chamber method is a method in which an object to be inspected is placed in a vacuum chamber, the inside of the object to be inspected is filled with a search gas, and the gas that flows out from the object to be inspected into the vacuum chamber is detected by a sensor.

[0003] In the vacuum chamber method, a diffusible gas that is easily detected by a sensor is used as a search gas. Helium gas was widely used as one of the search gases, but hydrogen gas is now being used more frequently due to a shortage of helium gas in the market caused by an increase in demand for helium gas.

[0004] For example, Patent Document 1 describes a pressure resistance inspection device for valves that includes a cover that houses a test valve in an unsealed state and a sensor that detects search gas containing hydrogen that has leaked from the test valve within the cover, and is configured to allow gas to flow within the cover and to ensure that the search gas that has leaked from the test valve reaches the sensor within the inspection time.

[0005] Such valve pressure resistance leak testing equipment using the vacuum chamber method is equipped with an instrument known as a flow standard, which produces a constant flow rate of reference leak calibration gas to be supplied into the chamber to inspect the hydrogen gas detection sensor that detects the hydrogen in the test gas.

[0006] Recently, the inspection standard for pressure resistance testing of valves has been set to a higher standard to enable the detection of even smaller leaks. For example, for industrial valves, a leak rate of less than 0.1 ml / min is now required.

[0007] In response to the demand for automation of valve manufacturing lines, pressure resistance testing using the vacuum chamber method has come to be incorporated as one of the steps in automatic production lines. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2019-158893 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, flow standards that produce minute leaks are difficult to obtain and expensive. Therefore, if a flow standard with a supply flow rate that produces minute leaks of less than 0.1 ml / min, for example, is provided in the pressure-resistance leak testing equipment for each valve on multiple production lines, there is a problem of increased equipment costs. That is, there is a problem that equipment costs increase in order to perform high-precision leak testing through automation.

[0010] The present invention has been developed to solve the problems in the related art, and an object of the present invention is to provide a valve pressure-resistance leak inspection method and valve pressure-resistance leak inspection device that are capable of performing high-precision leak inspection while reducing the cost of automated equipment. [Means for solving the problem]

[0011] In order to achieve the above object, the invention of claim 1 is a pressure-tight leak testing method for a valve, in which a test gas containing hydrogen is supplied to a valve body accommodated in a chamber, and the hydrogen in the chamber is detected by a gas sensor to perform a leak test, the hydrogen concentration of the calibration gas is made lower than the hydrogen concentration of the test gas so as to be approximately equal to the hydrogen atmosphere in the chamber to which the calibration gas is supplied at a supply flow rate required for quality, and the calibration gas is supplied at a supply flow rate required for quality, and the pass / fail of the leak test is determined based on detection data over time of hydrogen by the gas sensor of the calibration gas supplied at a supply flow rate required for quality.

[0012] The invention according to claim 2 is a pressure resistance leak inspection method for a valve, in which the hydrogen concentration and supply flow rate of the calibration gas are determined based on the product of the hydrogen concentration of the test gas and the supply flow rate based on the quality requirement.

[0013] The invention according to claim 3 is a pressure resistance leak inspection method for a valve in which the supply flow rate of the calibration gas is 0.1 ml / min or more.

[0014] The invention of claim 4 is a pressure-resistance leak testing method for a valve, in which the detection data is voltage value data output by the gas sensor in response to the hydrogen concentration over time as a calibration gas is supplied into a chamber, and a pass / fail determination is made for the leak test using a voltage value determined corresponding to a predetermined time of the detection data as a threshold value.

[0015] The invention of claim 5 is a pressure-tight leak testing device for a valve that supplies a test gas containing hydrogen to a valve body accommodated in a chamber and detects the hydrogen in the chamber with a gas sensor to test for leaks, the device having a calibration gas supply unit that supplies the calibration gas into the chamber with a hydrogen concentration lower than the hydrogen concentration of the test gas and higher than the supply flow rate required for quality so that the hydrogen concentration of the test gas is approximately equal to the hydrogen atmosphere in the chamber to which the calibration gas is supplied at a supply flow rate required for quality, and a leak test pass / fail determination processing unit that performs pass / fail determination processing for the leak test based on detection data over time of hydrogen by the gas sensor of the calibration gas supplied into the chamber.

[0016] The invention according to claim 6 is a pressure resistance leak inspection device for a valve, in which the hydrogen concentration and supply flow rate of the calibration gas are determined based on the product of the hydrogen concentration of the test gas and the supply flow rate based on the quality requirement.

[0017] The invention according to claim 7 is a pressure-tight leak inspection device for a valve, in which a gas sensor is disposed in a chamber so as to be able to detect hydrogen in an upper region within the chamber.

[0018] The invention according to claim 8 is a pressure-resistance leak inspection device for a valve in which the supply flow rate of the calibration gas is 0.1 ml / min or more.

[0019] The invention of claim 9 is a pressure-resistance leak testing device for a valve, in which the detection data is voltage value data output by the gas sensor in response to hydrogen concentration over time as a calibration gas is supplied into a chamber, and a leak test pass / fail determination processing unit determines whether the leak test passes or fails by using a voltage value determined corresponding to a specified time of the detection data as a threshold value. Effect of the Invention

[0020] According to the invention of claim 1, in a pressure resistance leak testing method for a valve, a test gas containing hydrogen is supplied to a valve body accommodated in a chamber, and the hydrogen in the chamber is detected by a gas sensor to test for leaks. The hydrogen concentration of the calibration gas is set lower than that of the test gas so as to be approximately equal to the hydrogen atmosphere in the chamber to which the calibration gas is supplied at a supply flow rate in accordance with the quality requirements, and the calibration gas is supplied into the chamber at a supply flow rate higher than the quality requirements. The pass / fail result of the leak test is determined based on detection data over time of hydrogen by the gas sensor of the calibration gas supplied into the chamber at a supply flow rate higher than the quality requirements. As a result, the inventors have discovered through their experiments that by supplying a calibration gas into a chamber with a hydrogen concentration lower than that of the test gas and at a supply flow rate higher than the quality requirement, it is possible to approximate the hydrogen atmosphere in the chamber when the calibration gas is supplied into the chamber with the hydrogen concentration of the test gas and at a supply flow rate higher than the quality requirement. By utilizing this, a highly accurate leak test can be performed based on detection data obtained by supplying a calibration gas into the chamber using a flow standard with a supply flow rate higher than the flow standard with a supply flow rate required by the quality requirement.As a result, a highly accurate leak test can be performed while keeping automation equipment costs down.

[0021] According to the invention of claim 2, the concentration and supply flow rate of the calibration gas are determined based on the product of the hydrogen concentration of the test gas and the supply flow rate based on the quality requirement. This makes it possible, based on the simple product of the hydrogen concentration and the flow rate supplied into the chamber, to make the hydrogen atmosphere in the chamber approximately equal to that when the calibration gas is supplied into the chamber at the hydrogen concentration of the test gas and at a flow rate required for quality.

[0022] According to the invention of claim 3, the supply flow rate of the calibration gas is 0.1 ml / min or more, so that the gas sensor can be inspected at a supply flow rate higher than the supply flow rate required by stricter quality requirements, and leak testing can be performed based on detection data determined at that higher supply flow rate. As a result, gas sensor inspection and valve leak testing can be performed using a general-purpose leak standard device with a relatively high supply flow rate.

[0023] According to the invention of claim 4, the detection data is voltage value data output by the gas sensor in response to the hydrogen concentration over time as the calibration gas is supplied into the chamber, and the pass / fail judgment of the leak test is made using a threshold voltage value determined corresponding to a specified time of the detection data. Therefore, a highly accurate leak test can be performed based on the voltage value detected by the gas sensor.

[0024] According to the invention of claim 5, a pressure-resistant leak testing device for a valve supplies a test gas containing hydrogen to a valve body accommodated in a chamber and detects the hydrogen in the chamber with a gas sensor to test for leaks, the device having a calibration gas supply unit that supplies calibration gas into the chamber at a hydrogen concentration lower than the hydrogen concentration of the test gas and higher than the supply flow rate required for quality so that the hydrogen concentration of the test gas is approximately equal to the hydrogen atmosphere in the chamber to which calibration gas is supplied at a supply flow rate required for quality, and a leak test pass / fail judgment processing unit that judges the pass / fail of the leak test based on detection data over time by the gas sensor of the calibration gas supplied into the chamber. As a result, the inventors have discovered through their experiments that by supplying a calibration gas into a chamber with a hydrogen concentration lower than that of the test gas and at a supply flow rate higher than the quality requirement, it is possible to approximate the hydrogen atmosphere in the chamber when the calibration gas is supplied into the chamber with the hydrogen concentration of the test gas and at a supply flow rate higher than the quality requirement. By utilizing this, highly accurate leak testing can be performed based on detection data obtained by supplying a calibration gas into the chamber using a flow standard with a supply flow rate higher than the flow standard for the supply flow rate required by the quality requirement.As a result, highly accurate leak testing can be performed while keeping automation equipment costs down.

[0025] According to the invention as set forth in claim 6, the hydrogen concentration and the supply flow rate of the calibration gas are determined based on the product of the hydrogen concentration of the test gas and the supply flow rate in accordance with the quality requirement. This makes it possible, based on the simple product of the hydrogen concentration and the flow rate supplied into the chamber, to make the hydrogen atmosphere in the chamber approximately equal to that when a calibration gas is supplied into the chamber at the hydrogen concentration of the test gas and at a flow rate required for quality, and a pass / fail judgment can be made based on the detection data of hydrogen in the chamber.

[0026] According to the invention of claim 7, the gas sensor is disposed in the chamber so as to be able to detect hydrogen in the upper region of the chamber. This makes it possible for the gas sensor to efficiently detect hydrogen in the test gas that leaks from the valve under inspection and rises to the upper region of the chamber. As a result, hydrogen leaking from various points in the valve under inspection can be efficiently detected while reducing the number of gas sensors installed.

[0027] According to the invention of claim 8, the supply flow rate of the calibration gas is 0.1 ml / min or more. This makes it possible to inspect gas sensors at a supply flow rate higher than the supply flow rate required for stricter quality, and to perform leak testing based on detection data determined at that higher supply flow rate. As a result, it is possible to inspect gas sensors and leak tests of valves that are compatible with stricter leak testing by using a general-purpose leak standard device with a relatively high supply flow rate.

[0028] According to the invention of claim 9, the detection data is voltage value data output by the gas sensor in response to the hydrogen concentration over time as the calibration gas is supplied into the chamber, and the leak test pass / fail determination processing unit determines whether the leak test passes or fails by using a voltage value determined corresponding to a specified time of the detection data as a threshold value. Therefore, a highly accurate leak test can be performed based on the voltage value detected by the gas sensor. [Brief description of the drawings]

[0029] [Figure 1] 1 is a block diagram showing a schematic configuration of a pressure resistance leak inspection device for a valve according to an embodiment of the present invention. [Diagram 2] 2 is a functional block diagram of the pressure resistance leak inspection device for the valve shown in FIG. 1. [Diagram 3] FIG. 2 is a perspective view showing the periphery of a chamber of the valve pressure resistance leak testing device. [Figure 4] FIG. 4 is a cross-sectional view of the pressure resistance leak inspection device for the valve shown in FIG. [Diagram 5] FIG. 1 is a simplified diagram of an experimental setup. [Figure 6] 6 is a graph showing the change over time in the voltage value output by the gas sensor obtained using the experimental apparatus shown in FIG. 5. [Figure 7] 4 is a flowchart showing a flow of a process for determining whether a valve leak test is passed or failed, which is performed by a control device of the valve pressure resistance leak test device. [Figure 8] 5 is a flowchart showing a flow of a gas sensor inspection process performed by a control device of the valve pressure resistance leak inspection device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a valve pressure-resistance leak inspection method and valve pressure-resistance leak inspection device 1 according to the present invention will be described in detail with reference to FIGS. The present disclosure is not limited to the embodiments shown below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of each element may differ from the reality. Furthermore, the drawings may include parts with different dimensional relationships and ratios. FIG. 1 is a block diagram showing a schematic configuration of a valve pressure leak inspection apparatus 1 according to an embodiment of the present invention. FIG. 2 is a functional block diagram of the valve pressure leak inspection apparatus 1 shown in FIG. 1. FIG. 3 is a perspective view showing the periphery of a chamber 10 of the valve pressure leak inspection apparatus 1. FIG. 4 is a cross-sectional view of the valve pressure leak inspection apparatus 1 shown in FIG. 3. FIG. 5 is a simplified diagram showing an experimental apparatus 100. FIG. 6 is a graph showing the time change in the voltage value output by the gas sensor 120 obtained using the experimental apparatus 100 shown in FIG. 5.

[0031] The pressure resistance leak inspection device 1 for a valve according to the embodiment of the present invention inspects the pressure resistance of a valve by checking the strength of the pressure-resistant portion of the valve and the presence or absence of leakage. This valve pressure resistance / leakage inspection device 1 is incorporated into a part of each valve production line and automatically inspects the pressure resistance of valves before shipping. Note that the valve pressure resistance / leakage inspection device 1 may be provided independently of the production line.

[0032] The valve pressure resistance leak testing apparatus 1 comprises a chamber 10 that accommodates a valve M to be tested, a test gas supply unit 20 that supplies a test gas containing a predetermined concentration of hydrogen into the test valve M accommodated in the chamber 10, six gas sensors 30 provided in the chamber 10 to detect hydrogen in the chamber 10, a calibration gas supply unit 40 that supplies a calibration gas G2 used for inspecting the gas sensors 30 from four locations into the chamber 10, a control device 50 that controls the operation of each part of the valve pressure resistance leak testing apparatus 1, and a display and operation device 60 that displays device information and accepts operations by an operator.

[0033] <About Chamber 10> The chamber 10 has an internal space 10a large enough to allow the inspection gas G1 leaking from the inspection target valve M housed therein to diffuse. In the present embodiment, the chamber 10 is generally cylindrical, but the shape of the chamber 10 is not limited to this and may be other shapes. For example, the chamber 10 may be cubic. Furthermore, the chamber 10 may have an internal space 10a that is semi-sealed as long as the gas sensor 30 can detect the inspection gas G1 leaking from the inspection target valve M.

[0034] <Regarding the inspection gas supply unit 20> The test gas supply unit 20 is configured with a test gas cylinder 21 that contains a mixed gas containing 5% hydrogen with a hydrogen to nitrogen ratio of 5:95 as high-pressure test gas G1, and an electromagnetic valve 22 connected to the test gas cylinder 21 via piping with a pressure adjustment regulator, pressure reducing valve, pressure gauge, etc. (not shown) provided in between. The high pressure test gas G1 contained in the test gas cylinder 21 has a hydrogen concentration of 5%, and is therefore safe to use.

[0035] <About the gas sensor 30> The gas sensor 30 is, for example, a commercially available hot-wire semiconductor hydrogen sensor capable of outputting a voltage value of 0 to 5V. This gas sensor 30 is a sensor that utilizes the change in electrical conductivity caused by the adsorption of hydrogen on the surface of a metal oxide semiconductor such as stannic oxide (SnO2), and is capable of providing a highly sensitive output even at low hydrogen concentrations, making it suitable for use in pressure resistance testing devices. The six gas sensors 30 used in this embodiment are connected to a commercially available digital potentiometer (not shown) for each channel, and the reference voltage can be adjusted by adjusting the resistance value.

[0036] 4, the six gas sensors 30 are disposed in an upper region of the internal space 10a of the chamber 10. Specifically, the six gas sensors 30 are disposed in an upper region of the internal space 10a of the chamber 10 in two rows of three, one above the other, along the outer periphery of the chamber 10, and when the two rows of gas sensors 30 are viewed from above, the six gas sensors 30 are dispersed at approximately equal intervals in the outer periphery. Therefore, the valve pressure resistance leak inspection device 1 is capable of efficiently detecting hydrogen leaking and rising from the inspected valve M by each gas sensor 30 in the upper region of the internal space 10a of the chamber 10.

[0037] Furthermore, from the experimental results described below, it is considered that by providing the gas sensor 30 in the upper region of the internal space 10a of the chamber 10, the effect on the diffusion rate of hydrogen within the chamber 10 caused by increasing the supply flow rate of the calibration gas G2 relative to the supply flow rate used to detect minute leaks can be reduced. In other words, it is possible to more closely approximate the state in which hydrogen is detected by the gas sensor 30 in a hydrogen atmosphere in the chamber 10 to which the calibration gas G2 is supplied at a hydrogen concentration of the test gas G1 (e.g., 5%) and a supply flow rate (e.g., 0.05 ml / min) required by quality requirements.

[0038] <Supply flow rate based on quality requirements> In this embodiment, the supply flow rate based on the quality requirements refers to the supply flow rate of the calibration gas G2 supplied into the chamber 10 in response to a minute amount of leakage from the valve in order to enable detection of even a minute amount of leakage from the valve in accordance with stricter inspection standards for pressure resistance inspection of the valve. For example, if a stricter inspection standard for a valve pressure test is to detect a leakage amount of 0.05 ml / min, the supply flow rate of the calibration gas G2 supplied into the chamber 10 is set to be equal to this minute leakage amount of 0.05 ml / min. For this reason, for example, when the supply flow rate of the calibration gas G2 supplied into the chamber 10 is set to 0.1 ml / min, this supply flow rate of the calibration gas G2 is greater than the supply flow rate required by the quality requirement.

[0039] <Regarding the calibration gas supply unit 40> The calibration gas supply unit 40 supplies calibration gas G2 into the chamber 10 at a hydrogen concentration lower than the hydrogen concentration of the test gas G1 (e.g., 5%) and higher than the supply flow rate required by the quality requirement so that the hydrogen concentration is approximately equal to the hydrogen atmosphere in the chamber 10 to which calibration gas G2 is supplied at a supply flow rate required by the quality requirement. In this embodiment, the calibration gas supply unit 40 supplies the calibration gas G2 having a hydrogen concentration of 2.5% into the chamber 10 at a flow rate of 1.0 ml / min. The calibration gas supply unit 40 includes a calibration gas cylinder 41 which contains a mixed gas containing 2.5% hydrogen with a hydrogen to nitrogen ratio of 2.5:97.5 as high-pressure calibration gas G2, a leak standard (hereinafter referred to as a "flow standard") 42 connected to the calibration gas cylinder 41 via piping with a pressure reducing valve, solenoid valve, etc. (not shown) provided in between, and four solenoid valves 43 which are connected in series to the flow standard 42 via piping so that the calibration gas G2 can be supplied into the chamber 10 from four locations. The high pressure calibration gas G2 contained in the calibration gas cylinder 41 has a hydrogen concentration of 2.5%, and is therefore safer to use than the test gas G1.

[0040] <Flow standard 42 of calibration gas supply unit 40> A commercially available flow standard with a supply flow rate of 0.1 ml / min is used as the flow standard 42. This flow standard 42 is easier to procure and less expensive than a standard with a comparatively smaller supply flow rate, for example, 0.05 ml / min.

[0041] <Regarding the four solenoid valves 43 of the calibration gas supply unit 40> The four solenoid valves 43 are three-way valves, and are connected in series with one another by connecting the normally open portion to the other solenoid valves 43 . As shown in FIG. 4, the solenoid valves 43 are arranged in two tiers, a lower region and an upper region, of the internal space 10a of the chamber 10 along the outer circumferential direction of the chamber 10. When the solenoid valves 43 arranged in two tiers, upper and lower, are viewed from above, the four solenoid valves 43 are distributed at approximately equal intervals in the outer circumferential direction. The calibration gas supply unit 40 may have other configurations as long as it can supply the inspection gas G2 into the chamber 10 from multiple locations at the supply flow rate of the flow standard 42.

[0042] <Regarding the control device 50> The control device 50 is realized by, for example, a PLC (Programmable Logic Controller), and is electrically connected to each component of the valve pressure resistance leak inspection device 1 as shown in FIG. The control device 50 has a calculation unit 51 consisting of a CPU (control processing unit), and a storage unit 52 consisting of a memory such as a ROM (read only memory) or a RAM (random access memory). The control device 50 is provided with an input circuit (not shown) that inputs signals output from each gas sensor 30 to the calculation unit 51, and an output circuit (not shown) that outputs signals from the calculation unit 51 to each solenoid valve 22, and signals are input and output between the control device 50 and each unit connected to the control device 50 through these circuits.

[0043] The calculation unit 51 includes a leak test pass / fail determination processing unit 51a that determines whether the leak test of the test target valve M passes or fails, and a gas sensor inspection processing unit 51b that performs inspection processing of the gas sensor 30. In this embodiment, a PLC is used as the control device, but the control device may be a microcontroller or the like other than a PLC as long as it has a calculation unit 51 and a memory unit 52 and can control each part of the valve pressure resistance leak testing device 1.

[0044] <Regarding the leak test pass / fail determination processing unit 51a of the control device 50> The leak test pass / fail determination processing unit 51a performs a pass / fail determination process for the leak test based on detection data over time of hydrogen by the gas sensor 30 of the calibration gas G2 supplied into the chamber 10 at a hydrogen concentration lower than that of the test gas G1 and a supply flow rate higher than the quality requirement so that the hydrogen concentration of the test gas G1 is approximately equal to the hydrogen atmosphere in the chamber 10 to which the calibration gas G2 is supplied at a supply flow rate specified by the quality requirement. In this embodiment, the supply flow rate required for quality is 0.05 ml / min, which is less than 0.1 ml / min, but the supply flow rate required for quality may be any other supply flow rate.

[0045] The detection data is data of a voltage value output by the gas sensor 30 in response to the hydrogen concentration over time while the calibration gas G2 is being supplied into the chamber 10. The leak test pass / fail determination processing unit 51a determines whether the leak test passes or fails using a voltage value determined corresponding to a predetermined time period of the detection data as a threshold value.

[0046] The threshold value serving as the criterion for judging whether the leak test is passed or failed by the leak test pass / fail judgment processing unit 51a is determined based on the findings from an experiment described below. Specifically, a calibration gas G2 with a hydrogen concentration of 2.5% is supplied from the calibration gas supply unit 40 into the chamber 10 of the valve pressure resistance leak testing device 1 at a supply flow rate of 0.1 ml / min, and a graph of the change in voltage value over time of each gas sensor 30 is obtained as in the experiment described below. The voltage value at a specified time on the graph, more specifically, the increased voltage value from the initial voltage value, is set as the threshold value. The threshold value thus set is stored in advance in the storage unit 52 as pass / fail judgment criteria data 52a. For example, to explain more specifically assuming that the graph shown in FIG. 6 is data acquired by the valve pressure resistance leak testing device 1, the voltage value after a predetermined time has elapsed, for example, 40 seconds, after the calibration gas G2 starts to be supplied into the chamber 10 is set as the threshold value. The predetermined time for setting the threshold value is not limited to 40 seconds, and may be adjusted appropriately depending on the specifications of the chamber 10, etc. Here, since the voltage value after 40 seconds differs for each gas sensor 30, for example, 0.1 V, which is the smallest increase in the voltage value, is set as the threshold value.

[0047] The hydrogen concentration and supply flow rate of this calibration gas G2 are determined based on the relationship between the product of the hydrogen concentration and the supply flow rate discovered by the inventors from the experimental results described below, i.e., the product of the hydrogen concentration of the test gas G1 and the supply flow rate of the calibration gas G2 into the chamber 10 based on the quality requirements. More specifically, the calibration gas G2 has a hydrogen concentration of 2.5% and a supply flow rate of 0.1 ml / min so that the product of the hydrogen concentration and the supply flow rate is equal to that of calibration gas G2, which has a hydrogen concentration of 5% and a supply flow rate of 0.05 ml / min in accordance with today's strict valve pressure testing standards.

[0048] In addition, the calibration gas G2 should be supplied into the chamber 10 with a hydrogen concentration lower than that of the test gas G1 and a supply flow rate higher than the quality requirement, so that the hydrogen concentration and supply flow rate can be set to be approximately equal to the hydrogen atmosphere in the chamber 10 to which the calibration gas G2 is supplied at the hydrogen concentration of the test gas G1 and the supply flow rate required by the quality requirement. For this reason, the product of the hydrogen concentration and the supply flow rate may be corrected to more closely approximate the hydrogen atmosphere in the chamber 10 to which the calibration gas G2 is supplied at a supply flow rate that satisfies the quality requirements.

[0049] <Regarding the gas sensor inspection processing unit 51b of the control device 50> The gas sensor inspection processing unit 51b performs inspection processing of the gas sensor 30 based on detection data over time of hydrogen by the gas sensor 30 of the calibration gas G2, which is supplied into the chamber 10 with a hydrogen concentration lower than that of the test gas G1 and a supply flow rate higher than the quality requirement.

[0050] The detection data is data of a voltage value output by the gas sensor 30 in response to the hydrogen concentration over time while the calibration gas G2 is being supplied into the chamber 10. The gas sensor inspection processing unit 51b judges the pass / fail of the gas sensor using a voltage value determined corresponding to a predetermined time period of the detection data as a threshold value. In this embodiment, the threshold value used by the gas sensor inspection processing unit 51b to judge the pass / fail status of the gas sensor 30 is set to be the same as that used by the leak test pass / fail judgment processing unit 51a, but a different voltage value may be set as the threshold value.

[0051] The storage unit 52 stores a control program for the valve pressure resistance leak test device 1 as well as various information related to the valve leak test process and the gas sensor inspection process. That is, the storage unit 52 stores pass / fail determination criteria data that is the basis for pass / fail determination of a valve to be inspected in a valve leakage inspection process and for pass / fail determination of a gas sensor in a gas sensor inspection process. This pass / fail judgment criteria data 52a is the voltage value that serves as the above-mentioned threshold value.

[0052] <Display and operation device 60> The display and operation device 60 is realized, for example, by a programmable display, and displays, for example, the pass / fail judgment result of the valve M to be inspected, information on the gas sensor 30 to be inspected, and the pass / fail judgment result of the gas sensor 30 to be inspected on a touch panel. The display / operation device 60 is configured so that an operator can operate the valve pressure resistance leak inspection device 1 via a touch panel. The display / operation device 60 is not limited to a touch panel, and may have a display function and an operation function independently. For example, a liquid crystal monitor with only a display function and a keyboard with only an operation function may be connected independently to the control device.

[0053] Here, the experiment on which the pass / fail judgment criteria data 52a stored in the storage unit 52 is based will be described below. <Experiments to derive pass / fail criteria for leak testing and gas sensors> Here, an explanation will be given of experiments carried out by the present inventors, which serve as the basis for leak testing and the pass / fail criteria for gas sensors. Through this experiment, the inventors discovered that by making the hydrogen concentration of the calibration gas G2 lower than that of the test gas G1 and supplying it into the chamber 10 at a flow rate higher than the quality requirement, it is possible to approximate the hydrogen atmosphere in the chamber 10 when the calibration gas G2 is supplied into the chamber 10 at the hydrogen concentration of the test gas G1 and at a flow rate higher than the quality requirement, and based on this, they set criteria for leak testing and pass / fail judgment of the gas sensor.

[0054] <About the Experimental Apparatus 100> As shown in Figure 5, the experimental apparatus 100 has a rectangular parallelepiped test box 110 created as a virtual chamber, with two gas sensors 120 on each of its four sides, for a total of eight gas sensors. A mixed gas supply pipe 130 is connected to one side so that mixed gas with variously changed hydrogen concentrations and supply flow rates can be supplied.

[0055] The configuration and specifications of each part of the experimental device 100 are shown below. Test box 110 material: plastic cardboard Dimensions of test box 110: 150 x 150 x 150 (mm) Gas sensor 120: SB-42A-11 manufactured by NISSHA FIS Co., Ltd. Gas supply piping 130: Gas cylinders, filter regulators, flow standards, solenoid valves, etc. are installed in the piping. Control board (not shown): electrically connected to eight gas sensors 120

[0056] <Experimental equipment method> A control program executed by the control board adjusts each gas sensor 120 to an initial voltage value of, for example, 2 V, and controls the solenoid valve to supply a mixed gas containing a predetermined concentration of hydrogen into the test box 110 . Then, for approximately 60 seconds after the supply of the mixed gas into the test box 110 is started, the hydrogen detected by the gas sensor 120 is output as a voltage value.

[0057] The mixed gas supplied to the test box 110 has various combinations of hydrogen concentration and supply flow rate, for example, a hydrogen concentration of 5% and a supply flow rate of 0.1 ml / min, or a hydrogen concentration of 5% and a supply flow rate of 0.05 ml / min, or a hydrogen concentration of 2.5% and a supply flow rate of 0.1 ml / min. Here, the mixed gas with a hydrogen concentration of 5% and a supply flow rate of 0.1 ml / min corresponds to the leak test standard for pressure resistance testing of valves using a flow standard that is relatively inexpensive and easily available. Moreover, a mixed gas with a hydrogen concentration of 5% and a supply flow rate of 0.05 ml / min corresponds to a leak indicated as a criterion for pressure resistance testing in this embodiment. The mixed gas with a hydrogen concentration of 2.5% and a supply flow rate of 0.1 ml / min had the hydrogen concentration and supply flow rate set so that the product of the hydrogen gas concentration and the supply flow rate was equal to that of the mixed gas with a hydrogen concentration of 5% and a supply flow rate of 0.05 ml / min. In this experiment, many more combinations of hydrogen concentrations and supply flow rates were used for the mixed gas, but the results of these experiments are omitted.

[0058] <Experimental equipment results> As shown in FIG. 6, the change in voltage value over time as the mixed gas was supplied was obtained as a graph. The upper graph (a) shows the change over time in the voltage value output by the gas sensor 120A placed on the top surface of the test box 110 in response to the hydrogen concentration in the test box 110, as shown in FIG. Moreover, the graph in the middle (b) shows the change over time in the voltage value output by the gas sensor 120C arranged on the side of the test box 110 in response to the hydrogen concentration in the test box 110, as shown in FIG. The graph (c) in the lower part shows the change over time in the voltage value output by the gas sensor 120E arranged on the side of the test box 110 in response to the hydrogen concentration in the test box 110, as shown in FIG.

[0059] As can be seen from graphs (a) to (c), the graph of the change in voltage value over time for a mixed gas with a hydrogen concentration of 2.5% and a supply flow rate of 0.1 ml / min is approximately equal to the graph of the change in voltage value over time for a mixed gas with a hydrogen concentration of 5% and a supply flow rate of 0.05 ml / min. In other words, the hydrogen atmosphere in the test box 110 supplied with a mixed gas having a hydrogen concentration of 2.5% and a supply flow rate of 0.1 ml / min is approximately equivalent to the hydrogen atmosphere in the test box 110 supplied with a mixed gas having a hydrogen concentration of 5% and a supply flow rate of 0.05 ml / min.

[0060] In other words, if the hydrogen concentration and the supply flow rate are set so that the product of the hydrogen concentration and the supply flow rate is equal, the hydrogen atmosphere can be made approximately equal to that inside the test box 110 to which a mixed gas with a hydrogen concentration of 5% and a supply flow rate of 0.05 ml / min, for example, which meets the strict inspection standards for valve pressure resistance testing, is supplied.

[0061] Based on this, the inventors of the present invention discovered that by setting the supply flow rate of the calibration gas G2 to, for example, 0.1 ml / min, which is higher than 0.05 ml / min used as an example, while setting the hydrogen concentration to 2.5%, which is lower than 5%, so that the product of this supply flow rate and the hydrogen concentration is equal, it is possible to create a hydrogen atmosphere in the chamber that meets the strict inspection standards for pressure resistance testing of valves. It was also discovered that, without the need to make the supply flow rate of the calibration gas G2 minute enough to meet the strict test standards, it is possible to perform tests equivalent to those strict test standards by lowering the hydrogen concentration.

[0062] The inventors also analyzed the experimental results and noted that, in particular, in graphs (b) and (c), i.e., the graphs for gas sensor 120C and gas sensor 120E, the graph of the voltage value of a mixed gas having a hydrogen concentration of 2.5% and a supply flow rate of 0.1 ml / min, more specifically, the graph of the increase in the voltage value from the initial voltage value, rises more quickly over time than the graph of the voltage value of a mixed gas having a hydrogen concentration of 5% and a supply flow rate of 0.05 ml / min. This is believed to be due to the fact that the mixed gas supplied at a flow rate of 0.1 ml / min had a greater flow rate than the mixed gas supplied at a flow rate of 0.05 ml / min, resulting in a faster diffusion rate of hydrogen within the test box 110. On the other hand, with regard to graph (a), we focused on the fact that hydrogen tends to rise and collect in the upper region of the test box 110, and that gas sensor 120A provided on the top surface of the test box 110 acts to reduce the influence of the magnitude of the supply flow rate by detecting hydrogen in the upper region of the test box 110.

[0063] Based on this, the inventors of the present invention discovered through this experiment that by arranging the gas sensor 30 in the chamber 10 so as to be able to detect hydrogen in the upper region of the chamber 10, the hydrogen of the test gas G1 that has leaked from the valve under inspection M and rises to the upper region of the chamber 10 can be efficiently detected by the gas sensor 30, and as a result, hydrogen leaking from various points in the valve under inspection M can be efficiently detected while reducing the number of gas sensors 30, and further, differences in the diffusion rate of hydrogen in the chamber 10 resulting from differences in the supply flow rate of the calibration gas G2 can be reduced.

[0064] <Valve leak inspection process flow> Next, the flow of the valve leak inspection process performed by the control device 50 including the leak inspection pass / fail determination processing unit 50a will be described with reference to FIG. FIG. 7 is a flowchart showing the flow of the valve leak inspection process performed by the control device 50 including the leak inspection pass / fail determination processor 50a. Here, as shown in FIG. 4, the valve pressure resistance leak testing device 1 is in a standby state in which the test target valve M has been set at a predetermined position in the chamber 10 and the device power has been turned on. The valve M to be inspected is placed on a plate 11 of the valve pressure resistance leak inspection device 1, and is sandwiched between a lifting jig 12 and the plate 11 and held in a chamber 10.

[0065] First, the control device 50 judges whether or not the test start button has been pressed (step S101), and if it is judged that the test start button has been pressed (step S101: Yes), the control device 50 proceeds to the process of step S102. Here, the control device 50 repeats this judgment process until it receives a signal from the display / operation device 60 instructing the start of the examination, and when the operator presses the start examination button on the touch panel of the display / operation device 60, it receives a signal from the display / operation device 60 instructing the start of the examination.

[0066] In step S102, the control device 50 ventilates the chamber 10. Here, the inside of the chamber is ventilated by a ventilation mechanism (not shown). Specifically, the control device 50 operates an exhaust fan installed at the top of the chamber 10, opens an exhaust valve connected to the exhaust flow path from inside the chamber 10, and opens an intake valve connected to the bottom of the chamber 10 to blow air into the valve, thereby ventilating the chamber.

[0067] Next, the control device 50 adjusts each gas sensor 30 to an initial voltage value (step 103). Here, the control device 50 adjusts the initial voltage value of each gas sensor 30 by automatically adjusting the resistance value corresponding to each gas sensor 30 using a digital potentiometer (not shown) connected to each gas sensor 30 for each channel.

[0068] Next, the control device 50 opens the solenoid valve 22 connected to the inspection gas cylinder 21 (step 104). As a result, the test gas G1 with a hydrogen concentration of 5% contained in the test gas cylinder 21 is supplied through the ventilation passage 11a formed in the plate 11 into the valve to be tested.

[0069] Then, the control device 50 starts detecting hydrogen by each gas sensor 30 (step S105). Here, the control device 50 starts measuring time at the same time that each gas sensor 30 starts detecting hydrogen.

[0070] Next, the control device 50 determines whether a predetermined time has elapsed (step S106). The control device 50 repeats this determination process until a predetermined time has elapsed, and proceeds to step S107 when it determines that the predetermined time has elapsed (step S106: Yes).

[0071] In step 107, the control device 50 determines whether or not there is a gas sensor 30 that returns a voltage value equal to or greater than a set threshold value. Here, the control device 50 acquires the voltage value, for example, 40 seconds after each gas sensor 30 starts detecting hydrogen, and determines whether the increased voltage value from the initial voltage value is greater than a threshold value (e.g., 0.1 V) pre-stored in the memory unit 52 as pass / fail judgment criteria data 52a.

[0072] If the control device 50 determines that there is a gas sensor 30 that returns a voltage value equal to or higher than the set threshold value (step S107: Yes), it displays on the touch panel of the display / operation device 60 that the valve M being inspected has failed, and ends the leak inspection process for this valve. Here, the operator confirms that the valve M being inspected has failed based on the inspection results displayed on the touch panel, and removes the valve M being inspected from the device and moves it to a designated location away from the production line, such as a storage area for rejected products.

[0073] On the other hand, if the control device 50 determines that there is no gas sensor 30 that returns a voltage value equal to or higher than the set threshold value (step S107: No), it displays on the touch panel of the display / operation device 60 that the valve M being inspected has passed, and ends the leak inspection process for this valve.

[0074] <Flow of inspection process for gas sensor 30> Next, a flow of the inspection process of the gas sensor 30 performed by the control device 50 including the gas sensor inspection processing unit 51b will be described with reference to FIG. FIG. 8 is a flowchart showing the flow of the inspection process for the gas sensor 30 performed by the control device 50 including the gas sensor inspection processing unit 51b. Here, the valve pressure resistance leak testing device 1 is in a standby state with the testing target valve M not set in the chamber 10 and the device power turned on.

[0075] First, the control device 50 determines whether or not the inspection start button has been pressed (step S201), and if it is determined that the inspection start button has been pressed (step S201: Yes), the control device 50 proceeds to the process of step S202. Here, the control device 50 repeats this judgment process until it receives a signal from the display / operation device 60 instructing it to start inspection, and when the operator presses the inspection start button on the touch panel of the display / operation device 60, it receives a signal from the display / operation device 60 instructing it to start inspection.

[0076] In step S202, the control device 50 ventilates the chamber 10. Here, the inside of the chamber is ventilated by a ventilation mechanism (not shown) in the same manner as in the above-mentioned valve leak inspection process.

[0077] Next, the control device 50 adjusts each gas sensor 30 to an initial voltage value (step S203). Here, the control device 50 adjusts the initial voltage value of each gas sensor 30 in the same manner as in the valve leak inspection process described above.

[0078] Next, the control device 50 displays the gas sensor 30 to be inspected (step S204). In this embodiment, the six gas sensors 30 are inspected in sequence, so the inspection order of the gas sensors 30 is preset in units of one or more. For this reason, information for identifying each individual gas sensor 30 is provided for each gas sensor 30. For example, each gas sensor 30 is provided with individual identification information such as a number, such as gas sensor 1, gas sensor 2, . . . , gas sensor 6. Therefore, in this process, the gas sensor 30 to be inspected is displayed on the touch panel of the display / operation device 60 as, for example, "gas sensor 1" or "gas sensor 1 and gas sensor 3." This allows the operator to confirm which of the multiple gas sensors 30 is currently being inspected.

[0079] Next, the control device 50 opens the solenoid valve 43 corresponding to the gas sensor 30 to be inspected (step S205). Here, a specific solenoid valve 43 out of four solenoid valves 43 arranged at various locations is assigned to each gas sensor 30. In other words, when one solenoid valve 43 is opened to supply the inspection gas G2 into the chamber, hydrogen is detected by the two gas sensors 30 around that one solenoid valve 43. For example, when calibration gas G2 is supplied into chamber 10 from one solenoid valve located near gas sensor 1 and gas sensor 3, hydrogen is detected by gas sensor 1 and gas sensor 3. On the other hand, when calibration gas G2 is supplied into chamber 10 from one solenoid valve located near gas sensor 2 and gas sensor 4, hydrogen is detected by gas sensor 2 and gas sensor 4. In other words, the gas sensors 30 corresponding to the plurality of solenoid valves 43 are separately inspected. In this way, the solenoid valve 43 corresponding to the gas sensor 30 to be inspected is opened, and calibration gas with a hydrogen concentration of 2.5% contained in the calibration gas cylinder 41 is supplied into the chamber 10 from the position of the corresponding solenoid valve 43 at a supply flow rate of 0.1 ml / min.

[0080] Then, the control device 50 starts detecting hydrogen by the gas sensor 30 to be inspected (step S206). Here, the gas sensor inspection processing unit 51b starts measuring time at the same time that each gas sensor 30 starts detecting hydrogen.

[0081] Next, the control device 50 determines whether a predetermined time has elapsed (step S207). The control device 50 repeats this determination process until a predetermined time has elapsed, and proceeds to step S208 if it determines that the predetermined time has elapsed (step S207: Yes).

[0082] In step S208, the control device 50 determines whether the voltage value returned by the gas sensor 30 to be inspected is equal to or greater than a set threshold value. Here, the control device 50 acquires the voltage value, for example, 40 seconds after the gas sensor 30 starts detecting hydrogen, calculates the increased voltage value from the initial voltage value (2 V), and determines whether the increased voltage value is greater than a threshold value (for example, 0.1 V) pre-stored in the memory unit 52 as pass / fail judgment criteria data 52a. In this embodiment, since two gas sensors 30 are assigned to one solenoid valve 43 as described above, the control device 50 may perform the judgment for the two target gas sensors 30 simultaneously, or may perform the judgment for each gas sensor 30 separately. Furthermore, the threshold value used to determine the pass / fail performance of the gas sensor 30 may be set to one common threshold value for all the gas sensors 30, or an individual threshold value may be set for each gas sensor 30.

[0083] If the control device 50 determines that the voltage value returned by the gas sensor 30 being inspected is equal to or greater than the set threshold value (step S208: Yes), it stores in the memory unit 52 that the gas sensor 30 being inspected has passed (step S209), and determines whether all of the gas sensors 30 have passed (step S210).

[0084] In step S210, if the control device 50 determines that all the gas sensors 30 have passed the test (step S210: Yes), the control device 50 displays that all the gas sensors 30 have passed the test (step S211). Here, the control device 50 displays, for example, "All Gas Sensors Passed" on the touch panel of the display / operation device 60, and ends the inspection process for this gas sensor 30. . This allows the operator to confirm that inspection of all the gas sensors 30 has been completed without any problems.

[0085] Furthermore, in step S210, if the control device 50 determines that all the gas sensors 30 have not passed the test (step S210: No), the control device 50 returns the process to step S202 and repeats the above-mentioned processes.

[0086] On the other hand, in step S208, if the control device 50 determines that the voltage value output by the gas sensor 30 being inspected is smaller than the set threshold value (step S208: No), it displays that the gas sensor 30 being inspected has failed (step S212). In this process, the gas sensor 30 that has been determined to be a failure is displayed on the touch panel of the display / operation device 60 as, for example, "Gas sensor 1 failed." This enables the operator to confirm that there is a failed gas sensor 30 and that the gas sensor 30 needs to be replaced.

[0087] Thereafter, the control device 50 determines whether or not the inspection end button has been pressed until the inspection end button is pressed, and if the inspection end button has been pressed (step S213: Yes), ends the inspection process of this gas sensor. At this point, the operator ends the inspection process in order to replace the failed gas sensor 30. In the inspection process for the gas sensor 30 described here, the inspection process is terminated when one gas sensor 30 fails, but the inspection process may be terminated after determining whether all gas sensors 30 pass or fail.

[0088] <Effects of the embodiment> As described above, according to the pressure resistance leak testing method for a valve of an embodiment of the present invention, the hydrogen concentration of the calibration gas is set lower than that of the test gas G1 so as to be approximately equal to the hydrogen atmosphere in the chamber 10 to which the calibration gas G2 is supplied at a supply flow rate in accordance with the quality requirements, and the pass / fail result of the leak test is determined based on detection data over time of hydrogen by the gas sensor 30 of the calibration gas G2 supplied into the chamber 10 at a supply flow rate higher than the quality requirements. As a result, the inventors of the present invention have discovered through experiments that by making the hydrogen concentration of the calibration gas G lower than that of the test gas G1 and supplying the calibration gas G2 into the chamber 10 at a flow rate higher than the quality requirement, it is possible to approximate the hydrogen atmosphere in the chamber 10 when the calibration gas G2 is supplied into the chamber 10 at the hydrogen concentration of the test gas G1 and at a flow rate higher than the quality requirement. By utilizing this, a highly accurate leak test can be performed based on detection data obtained by supplying the calibration gas G2 into the chamber 10 using a flow standard 42 with a supply flow rate of 0.1 ml / min, which is higher than the flow standard with a supply flow rate of 0.05 ml / min required by the quality requirement, for example. As a result, a highly accurate leak test can be performed while reducing the equipment costs for automation.

[0089] Furthermore, according to the valve pressure resistance leak testing method of the embodiment of the present invention, the hydrogen gas concentration and supply flow rate of the calibration gas G2 are determined based on the product of the hydrogen concentration of the test gas G1 and the supply flow rate based on the quality requirement. As a result, based on the simple product of the hydrogen concentration and the supply flow rate into the chamber 10, the hydrogen atmosphere in the chamber 10 can be made approximately equal to that when the calibration gas G2 is supplied into the chamber at the hydrogen concentration of the test gas G1 and at a supply flow rate required by quality requirements, and a pass / fail judgment of the leak test can be made based on the detection data of hydrogen in the chamber 10.

[0090] Furthermore, according to the pressure resistance leak testing method for a valve according to the embodiment of the present invention, the supply flow rate of the calibration gas G2 is 0.1 ml / min or more, so that the gas sensor 30 can be inspected at a supply flow rate that is higher than the supply flow rate required by stricter quality requirements, and leak testing can be performed based on detection data determined at a supply flow rate of 0.1 ml / min or more. As a result, the gas sensor 30 can be inspected and the valve can be inspected for leaks using a general-purpose flow standard 42 with a relatively high supply flow rate.

[0091] Furthermore, according to the pressure resistance leak testing method for a valve according to an embodiment of the present invention, the detection data is voltage value data output by the gas sensor 30 in response to the hydrogen concentration over time as the calibration gas G2 is supplied into the chamber 10, and the pass / fail judgment of the leak test is made using a threshold voltage value determined corresponding to a predetermined time of the detection data. Therefore, a highly accurate leak test can be performed based on the voltage value detected by the gas sensor 30.

[0092] In addition, the pressure-resistant leak testing device 1 for a valve according to an embodiment of the present invention includes a calibration gas supply unit 40 that supplies calibration gas G2 into the chamber 10 with a hydrogen concentration lower than the hydrogen concentration of the test gas G1 and higher than the supply flow rate required for quality so that the hydrogen concentration of the test gas G1 is approximately equal to the hydrogen atmosphere in the chamber 10 to which calibration gas G2 is supplied at a supply flow rate required for quality, and a leak test pass / fail judgment processing unit 51a that judges the pass / fail of the leak test based on detection data over time of hydrogen by the gas sensor 30 of the calibration gas G2 supplied into the chamber 10. As a result, the inventors of the present invention have discovered through their experiments that by supplying the calibration gas G2 into the chamber 10 with a hydrogen concentration lower than that of the test gas G1 and at a supply flow rate higher than the quality requirement, it is possible to approximate the hydrogen atmosphere in the chamber 10 when the calibration gas G2 is supplied into the chamber 10 with the hydrogen concentration of the test gas G1 and at a supply flow rate higher than the quality requirement. By utilizing this, a highly accurate leak test can be performed based on detection data obtained by supplying the calibration gas G2 into the chamber 10 using a flow standard 42 with a supply flow rate of 0.1 ml / min, which is higher than the flow standard with a supply flow rate of 0.05 ml / min required by the quality requirement, for example. As a result, a highly accurate leak test can be performed while reducing the equipment costs for automation.

[0093] In addition, according to the valve pressure resistance leak testing device 1 of the embodiment of the present invention, the hydrogen concentration and supply flow rate of the calibration gas G2 are determined based on the product of the hydrogen concentration of the test gas G1 and the supply flow rate of the calibration gas G2 into the chamber 10 based on the quality requirement. As a result, based on the simple product of the hydrogen concentration and the supply flow rate into chamber 10, the hydrogen atmosphere in chamber 10 can be made approximately equal to that obtained when calibration gas G2 is supplied into chamber 10 at the hydrogen concentration of the test gas G1 and at a supply flow rate required by quality requirements, and a pass / fail judgment can be made on the basis of the detection data for hydrogen in chamber 10.

[0094] Furthermore, according to the valve pressure resistance leak testing device 1 of the embodiment of the present invention, the gas sensor 30 is disposed in the chamber 10 so as to be able to detect hydrogen in the upper region of the chamber 10. This allows the gas sensor 30 to efficiently detect hydrogen in the test gas G1 that has leaked from the test target valve M and risen to the upper region of the chamber 10. As a result, hydrogen leaking from various points in the test target valve M can be efficiently detected while reducing the number of gas sensors 30 installed.

[0095] Furthermore, according to the pressure resistance leak test device 1 for a valve of the embodiment of the present invention, the supply flow rate of the calibration gas G2 is 0.1 ml / min or more, so that the gas sensor 30 can be inspected at a supply flow rate that is higher than the supply flow rate required for stricter quality, and leak testing can be performed based on detection data determined at a supply flow rate of 0.1 ml / min or more. As a result, inspection of the gas sensor 30 and leak testing of the valve can be performed using a general-purpose leak standard device with a relatively high supply flow rate.

[0096] Furthermore, according to the valve pressure resistance leak testing device 1 of the embodiment of the present invention, the detection data is voltage value data output by the gas sensor 30 in response to the hydrogen concentration over time as the calibration gas G2 is supplied into the chamber 10, and the leak test pass / fail determination processing unit 51a determines whether the leak test has passed or failed by using a voltage value determined corresponding to a predetermined time of the detection data as a threshold value. Therefore, a highly accurate leak test can be performed based on the voltage value detected by the gas sensor 30.

[0097] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0098] For example, in the above embodiment, the pass / fail of the inspection target valve M and the gas sensor 30 is judged using data of the voltage value output by the gas sensor 30 in response to the hydrogen concentration, but this is not limited thereto, and pass / fail may be judged by outputting data other than the voltage value by the gas sensor 30. For example, the pass / fail of the inspection target valve M and the gas sensor 30 may be judged using a current value output by the gas sensor 30 in response to the hydrogen concentration.

[0099] In addition, for example, in the above embodiment, a mixed gas containing 2.5% hydrogen is used as the calibration gas G2, but the hydrogen concentration of the calibration gas G2 may be adjusted according to the supply flow rate. More specifically, the hydrogen concentration and the supply flow rate may be appropriately set so that the hydrogen concentration of the inspection gas G1 and the hydrogen atmosphere in the chamber 10 to which the calibration gas G2 is supplied at a supply flow rate based on the quality requirements are approximately equal. For example, if the hydrogen concentration of the test gas G1 is 5% and the supply flow rate of the flow standard required for quality is 0.006 ml / min, based on the relationship between the product of the hydrogen concentration of the test gas G1 and the supply flow rate of the flow standard required for quality, and the product of the hydrogen concentration of the calibration gas G2 and the supply flow rate of the calibration gas G2 into the chamber 10, the hydrogen concentration of the calibration gas G2 should be set to 0.3% and the supply flow rate to 0.1 ml / min.

[0100] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0101] 1 Valve pressure resistance and leak testing device 10. Chamber 10a Internal space 11 Plate 11a Ventilation passage 12 Lifting fixture 13 Cover 20. Inspection gas supply section 21 Gas cylinder for testing 22 Solenoid valve 30 Gas Sensor 40 Calibration gas supply unit 41 Calibration gas cylinder 42 Flow Standard (Leak Standard) 43 Solenoid valve 50 Control device 51 Arithmetic section 51a Leak inspection pass / fail judgment processing section 51b Gas sensor inspection processing section 52 Storage section 52a Pass / Fail Criteria Data 60 Display / operation device 100 Experimental Equipment 110 Test Box 120, 120A, 120C, 120E Gas Sensor 130 Gas supply pipe G1 Test Gas G2 Inspection gas M Valve to be inspected

Claims

1. A pressure resistance leak inspection method for a valve, comprising the steps of supplying a test gas containing hydrogen to a valve body accommodated in a chamber and detecting the hydrogen in the chamber with a gas sensor, comprising: A pressure-resistant leak inspection method for a valve, characterized in that the hydrogen concentration of the calibration gas is made lower than the hydrogen concentration of the test gas and is supplied into the chamber at a supply flow rate greater than the quality requirement so that the hydrogen concentration of the test gas is approximately equal to the hydrogen atmosphere in the chamber to which the calibration gas is supplied at the quality requirement supply flow rate, and the pass / fail of the leak inspection is determined based on detection data over time of hydrogen by the gas sensor of the calibration gas supplied into the chamber at a supply flow rate greater than the quality requirement.

2. The calibration gas is 2. The method for inspecting a valve for pressure resistance and leakage according to claim 1, wherein the hydrogen concentration and the supply flow rate are determined based on the product of the hydrogen concentration of the inspection gas and the supply flow rate based on the quality requirement.

3. 3. The method for inspecting pressure resistance and leakage of a valve according to claim 1, wherein the supply flow rate of the calibration gas is 0.1 ml / min or more.

4. the detection data is data of a voltage value output by the gas sensor in response to a hydrogen concentration over time as the calibration gas is supplied into the chamber; 3. The pressure resistance leak inspection method for a valve according to claim 1, wherein pass / fail of the leak inspection is judged using a voltage value determined corresponding to a predetermined time period of the detection data as a threshold value.

5. A pressure-resistance leak inspection device for a valve supplies a test gas containing hydrogen to a valve body accommodated in a chamber, and detects the hydrogen in the chamber with a gas sensor to inspect the valve for leaks, a calibration gas supply unit that supplies the calibration gas into the chamber at a hydrogen concentration lower than that of the test gas and at a supply flow rate higher than that required by quality requirements so that the hydrogen concentration of the test gas is approximately equal to that of the hydrogen atmosphere in the chamber to which the calibration gas is supplied at a supply flow rate required by quality requirements; and a leak test pass / fail determination processing unit that performs pass / fail determination processing on the basis of detection data over time of hydrogen by the gas sensor of the calibration gas supplied into the chamber.

6. The calibration gas is 6. The pressure resistance leak inspection device for a valve according to claim 5, wherein the hydrogen concentration and the supply flow rate are determined based on the product of the hydrogen concentration of the inspection gas and the supply flow rate based on the quality requirement.

7. 7. The pressure resistance leak inspection device for a valve according to claim 5, wherein the gas sensor is disposed in the chamber so as to be able to detect hydrogen in an upper region within the chamber.

8. 7. The pressure resistance leak inspection device for a valve according to claim 5, wherein the supply flow rate of the calibration gas is 0.1 ml / min or more.

9. the detection data is data of a voltage value output by the gas sensor in response to a hydrogen concentration over time as the calibration gas is supplied into the chamber; 7. The pressure resistance leak inspection device for a valve according to claim 5, wherein the leak inspection pass / fail determination processing section determines pass / fail of the leak inspection using a voltage value determined corresponding to a predetermined time period of the detection data as a threshold value.

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