JP5142802B2 - Equipment for measuring mechanical properties under high-pressure hydrogen gas atmosphere - Google Patents

Description

  The present invention relates to a test apparatus for performing a tensile test, a fatigue test, etc. in order to measure and evaluate mechanical properties of a metal material, etc. in a high-pressure hydrogen gas atmosphere, and in particular, to ensure safety of this test apparatus. About.

As is well known, hydrogen gas is highly reducible and easily diffuses into the metal or forms a hydrogen compound. For this reason, when the use of metal materials for various applications is considered, the material properties in a hydrogen gas environment, particularly hydrogen affects the metal bonding and causes the metal materials to become brittle (hydrogen embrittlement). It should be noted that hydrogen changes the strength properties of metallic materials. Therefore, for materials that are concerned about hydrogen embrittlement, etc., an atmosphere gas such as hydrogen gas is introduced and the tensile strength, compressive strength, bending strength, tensile fatigue strength, etc. of the metal material in a high temperature or high pressure environment It is necessary to measure the mechanical properties.

Further, since hydrogen gas is flammable and easily ignites or explodes when mixed with air, safety considerations are required for its use. Therefore, various safety measures are usually taken for a test apparatus that forms a high-pressure hydrogen gas atmosphere.
By the way, in recent years, global warming has become a problem, and research and development on a technique for reducing the emission of carbon dioxide, which is the cause, has been promoted. For example, hydrogen vehicles equipped with a hydrogen engine that burns hydrogen and electric vehicles that use hydrogen as an energy source are put to practical use instead of conventional hydrocarbon fuels such as gasoline or light oil. It is going to be done. In the case of such a hydrogen vehicle or an electric vehicle, the distance that can be traveled by one charge is required to be sufficiently long in practice. For this reason, there is an expectation for a method of loading a compressed hydrogen cylinder as a method that is closest to practical use as a hydrogen source mounted on an automobile.

Until several years ago, the pressure of this compressed hydrogen cylinder was about 35 MPa, and the travel distance in one fuel charge was 300 km or less. It has been studied to improve the travel distance to a practical 500 km, and the pressure of the compressed hydrogen cylinder has reached about 70 MPa.
Regarding the materials of equipment used in such a high-pressure hydrogen gas atmosphere, although the above-mentioned problems such as hydrogen embrittlement are concerned, the mechanical properties of various materials in such a high-pressure hydrogen gas atmosphere have so far been concerned. There is not enough data on these properties, and even material standards have not been established. In order to evaluate the mechanical characteristics, naturally, a test apparatus capable of forming such a high-pressure hydrogen gas atmosphere is necessary. However, it is actually difficult to obtain a sufficient test apparatus from the viewpoint of safety.

On the other hand, a hot isostatic pressing apparatus (HIP apparatus) that uses high-pressure (about 70 MPa) argon or nitrogen as a pressure medium is industrially known. Since there are many achievements as a structure of an apparatus for safely confining high-pressure gas, it is possible to divert the high-pressure vessel of this HIP apparatus to a test apparatus under a high-pressure hydrogen gas atmosphere.
However, when hydrogen gas is sealed in the high pressure container of the HIP device, unlike argon or nitrogen sealing, hydrogen gas leakage through the sealing part between the lid and body of the high pressure container is very dangerous and explodes. Or there is a great risk of an accident such as a fire.

  For this reason, safety considerations are necessary for leakage of hydrogen gas from a high-pressure vessel used in an HIP device or the like, but no countermeasure has been taken. Even if it is adopted, a method of detecting a hydrogen gas leak by merely arranging a hydrogen gas leak sensor inside the room where the high-pressure vessel is installed has been adopted. However, no good method has been proposed, although it is preferable to detect the leak before the hydrogen gas leaking from the high pressure vessel fills the room.

In addition, the following are well-known as a technique which can introduce | transduce highly explosive or highly reactive atmospheric gas, such as hydrogen gas, and can perform a tensile test of a material and other tests at high temperature.
Patent Document 1 discloses a mechanical property test apparatus that arranges a test member in a high-pressure vessel into which high-pressure gas is introduced, and applies a load to the test member to measure the deformation amount of the test member. This test apparatus includes a cylindrical main body having an opening at at least one end, and a lid that closes the opening in an openable and closable manner. The axial force applied to the lid when high-pressure gas is introduced into the high-pressure vessel is carried by the press frame that can be engaged and disengaged from the outside in the high-pressure vessel. The deformation amount of the test member is measured by an actuator unit that applies a load to the test member fixed to the lid through a rod that penetrates the lid. Further, the test frame can be mounted and removed by releasing the press frame and opening the lid.

Patent Document 2 discloses a heating furnace for a material testing machine in which a heater having an electrically insulated surface is disposed inside a chamber having a gas inlet and a gas outlet. In this heating furnace, a shaft insertion port for inserting the shaft of the material testing machine is formed on the wall of the chamber, and an extendable shaft seal member for hermetically sealing the shaft is attached to the shaft insertion port.
JP 2004-340920 A JP 2005-3517 A

However, Patent Document 1 described above describes a container structure of a mechanical property test apparatus in a high-pressure gas atmosphere containing hydrogen gas, but does not disclose measures against hydrogen gas leakage from the high-pressure container.
The technique disclosed in Patent Document 2 uses a bellows to seal with a tester. However, when the atmospheric gas pressure is high, the bellows has a low pressure resistance and cannot be applied. Cannot be excluded. In addition, measures against hydrogen gas leakage from the high-pressure vessel are not disclosed.

  Therefore, in view of the above problems, the present invention is a mechanical property test that is performed by placing a test member in a high-pressure vessel filled with hydrogen gas and placing the high-pressure vessel in a thermostatic chamber into which nitrogen gas has been introduced. An object of the present invention is to provide a device having a measure against hydrogen gas leakage from a high-pressure vessel, that is, a device that detects and notifies hydrogen gas leakage.

In order to achieve the above-described object, the present invention takes the following technical means.
That is, the machine characteristic measuring apparatus under a high-pressure hydrogen gas atmosphere according to the present invention, a high-pressure vessel test member the mechanical properties are measured under a high pressure of hydrogen gas atmosphere disposed therein, the nitrogen gas into the A constant temperature bath that is filled with the high-pressure vessel and is capable of controlling the temperature of the nitrogen gas, a circulation mechanism that circulates the nitrogen gas inside and outside the constant temperature bath, and the circulation mechanism And a hydrogen gas detector.

According to the above-described mechanical property measuring apparatus, even if hydrogen gas leaks from the high pressure vessel, it is excellent in safety because it leaks into nitrogen gas.
Preferably, an alarm transmission mechanism that issues an alarm when the amount of hydrogen gas detected by the hydrogen gas detector is equal to or greater than a predetermined value may be provided.
Furthermore, when the hydrogen gas amount detected by the hydrogen gas detector is equal to or greater than a predetermined value, a safety mechanism for releasing the hydrogen gas inside the high-pressure vessel to the outdoors may be provided.
The most preferable embodiment of the mechanical property measuring apparatus under a high-pressure hydrogen gas atmosphere according to the present invention includes a high-pressure vessel in which a test member for measuring mechanical properties in a high-pressure hydrogen gas atmosphere is disposed, and a nitrogen gas therein. And a high temperature vessel in which the high pressure vessel is arranged, a circulation mechanism for circulating nitrogen gas inside and outside the constant temperature vessel, a hydrogen gas detector provided in the circulation mechanism, and a constant temperature bath by the circulation mechanism A medium circulation heater that is disposed on the circulation of nitrogen gas in the inside and controls the temperature of the nitrogen gas in the thermostat; and a stirring fan that stirs the nitrogen gas in the thermostat. To do.

According to mechanical properties measurements equipment under high pressure hydrogen atmosphere according to the present invention, it is possible to safely measure the mechanical properties of metal materials under high-pressure hydrogen gas environment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.
[First embodiment (reference example) ]
As shown in FIGS. 1 and 2, a mechanical property measuring apparatus 100 under a high-pressure hydrogen gas atmosphere according to the present embodiment includes a thermostatic chamber 1 and a high-pressure vessel 2 arranged in the thermostatic chamber. The

  The high-pressure vessel 2 includes a cylindrical body (body portion) 41 including a test chamber 40 that can accommodate high-pressure hydrogen gas. The cylindrical body 41 has an opening 42 that is open downward, and has a shape in which the cup is turned down. A lower lid 43 is fitted into the opening 42 of the cylindrical body, and a material mechanical test such as a tensile test and a compression test is performed on the upper surface of the lower lid 43 in a high-pressure hydrogen gas atmosphere. The test jig 8 is provided. A pull rod 11 that applies a tensile force or a compressive force to the test member 44 is provided below the test jig 8, and the pull rod 11 is driven by the hydraulic pressure supplied from the hydraulic unit 26 through the hydraulic line 27.

A heat medium jacket 9 is provided around the high-pressure vessel 2. Due to the heat medium jacket 9, a jacket pipe line 29 is formed on the outer periphery of the cylindrical body 41. This jacket line 29
Is connected to a temperature adjustment unit 23 such as a heat exchanger by a jacket medium supply line 24 and a jacket medium return line 25.
Inside the thermostatic chamber 1, a high-pressure vessel 2, a stirring fan 3, a medium circulation heater 4, and a nitrogen gas introduction pipe 5 (supply mechanism) are provided.

A nitrogen gas discharge pipe 6 (discharge mechanism) is provided above the thermostat 1, and a hydrogen gas detection sensor 7 is provided in the nitrogen gas discharge pipe 6.
A hydrogen gas introduction line 10 is provided below the high-pressure vessel 2. A pull rod 11 that displaces the test jig 8 is attached below the high-pressure vessel 2, and the pull rod 11 penetrates outside the thermostatic chamber 1.

  A hydrogen gas introduction pipe line 10 connected to the lower side of the high-pressure vessel 2 is connected to a hydrogen cylinder 14 installed outside. The hydrogen gas introduction pipe line 10 is provided with a compressor 15 and an opening / closing valve 17 from the hydrogen cylinder 14 side. Further, a hydrogen gas discharge pipe 18 extending to the outdoors (in the atmosphere) is provided above the high-pressure vessel 2. The hydrogen gas discharge pipe 18 is provided with an open / close valve 19.

The compressor 15 is driven by a motor 16. When the compressor 15 is driven by the motor 16 with the open / close valve 17 open and the open / close valve 19 closed, the hydrogen gas supplied from the hydrogen cylinder 14 to the compressor 15 is compressed (pressurized). The gas is introduced into the high-pressure vessel 2 through the hydrogen gas introduction line 10.
When the opening / closing valve 19 is opened while the opening / closing valve 17 is closed, the hydrogen gas in the high-pressure vessel 2 is discharged to the outside (in the atmosphere) through the hydrogen gas discharge pipe 18.

The nitrogen gas introduction pipe line 5 is connected to the nitrogen cylinder 12 via the opening / closing valve 13. The nitrogen in the nitrogen cylinder 12 may be liquid or gas. When the opening / closing valve 13 is opened, nitrogen in the nitrogen cylinder is introduced into the thermostatic chamber 1 through the nitrogen gas introduction pipe 5, and is stirred by the stirring fan 3, so that the thermostatic bath 1 is filled with nitrogen.
In the present embodiment, the nitrogen gas filled in the thermostatic chamber 1 is not circulated but discharged to the outside through the nitrogen gas discharge line 6. The nitrogen gas discharge pipe 6 is provided with a hydrogen gas detection sensor 7 for detecting hydrogen gas.

  When hydrogen gas leaks from the high-pressure vessel 2, it leaks into the nitrogen gas filled in the thermostatic chamber 1 and is excellent in safety. Since nitrogen gas is always supplied from the nitrogen gas introduction line 5, a certain amount of nitrogen gas is discharged from the nitrogen gas discharge line 6. A hydrogen gas detection sensor 7 (hydrogen gas detector) is attached to the nitrogen gas discharge pipe 6, and the hydrogen gas detection sensor 7 detects leakage of hydrogen gas. An alarm 28 (alarm transmission mechanism) that receives a signal from the hydrogen gas detection sensor 7 and generates an alarm is provided.

Furthermore, when the amount of hydrogen gas detected by the hydrogen gas detection sensor 7 is equal to or greater than a predetermined value, the on-off valve 19 is forcibly opened to allow the hydrogen gas inside the high-pressure vessel 2 to be outdoors (in the atmosphere). A safety mechanism (not shown) for discharging or stopping the operation of the mechanical property measuring apparatus 100 is provided.
Based on the fact that the flammable range of hydrogen in the air is 4% to 75%, two values are preset as the hydrogen gas leak alarm value. In consideration of the safety factor, for example, 400 ppm (0.04%) is set as a setting value for alarm generation and operation stop. Further, 1000 ppm (0.1%) is set as a set value for opening the on-off valve 19 and discharging the hydrogen gas in the high-pressure vessel 2 to the outside through the hydrogen gas discharge pipe 18. Note that these set values are examples, and the present invention is not limited to these set values.

The medium circulation heater 4 is connected to a temperature adjustment unit 20 such as a heat exchanger by a medium supply line 21 and a medium return line 22.
When heating the thermostat 1, the heated medium is circulated between the medium circulation heater 4 and the temperature adjustment unit 20 such as a heat exchanger, and nitrogen gas is supplied from the nitrogen gas introduction line 5. Nitrogen gas in the thermostat 1 is stirred by the stirring fan 3. The medium supply line 21 and the medium return line 22 may be reversed.

When cooling the thermostat 1, the cooled medium is circulated between the medium circulation heater 4 and the temperature adjustment unit 20. Instead of this, or in addition to this, liquid nitrogen may be supplied from the nitrogen gas introduction line 5 and stirred by the stirring fan 3.
On the other hand, in order to shorten the heating time for raising the temperature in the high pressure vessel 2, it is preferable to circulate the heat medium between the heat medium jacket 9 on the outer periphery of the high pressure vessel 2 and the temperature adjustment unit 23. The temperature adjustment unit 23 may also be used as the temperature adjustment unit 20. In order to shorten the cooling time for lowering the temperature in the high-pressure vessel 2, it is also possible to circulate the cooling medium between the heat medium jacket 9 and the temperature adjustment unit 23.

A usage mode of the mechanical property measuring apparatus 100 in a high-pressure hydrogen gas atmosphere having the above-described structure will be described. It is assumed that the setting of the test member 44 to the test jig 11 in the high-pressure vessel 2 has been completed.
The on-off valve 17 is opened, the on-off valve 19 is closed, and the compressor 15 is driven by the motor 16 to supply hydrogen gas from the hydrogen cylinder 14 into the high-pressure vessel 2. At this time, hydrogen gas is supplied from the hydrogen cylinder 14 to the high-pressure vessel 2 through the hydrogen gas introduction conduit 10 so that the pressure in the high-pressure vessel 2 becomes about 90 MPa.

  When the pressure of the hydrogen gas in the high-pressure vessel 2 reaches a predetermined pressure (may be before the predetermined pressure is reached), the open / close valve 13 is opened and nitrogen gas is supplied to the thermostatic chamber through the nitrogen gas introduction pipe 5. 1 is introduced. At this time, the heat medium or the cooling medium is circulated between the medium circulation heater 4 and the temperature adjustment unit 20 and the stirring fan 3 is operated to adjust the temperature in the thermostatic chamber 1. Further, the heat medium or the cooling medium is circulated between the jacket conduit 29 of the heat medium jacket 9 and the temperature adjusting unit 23 to adjust the temperature in the high-pressure vessel 2.

When the pressure and temperature in the high-pressure vessel 2 reach predetermined values, the pull rod 11 is operated by the hydraulic pressure supplied through the hydraulic line 27 by operating the hydraulic unit 26, and the tensile load applied to the test member 44. The displacement of the test member 44 relative to is measured.
An abnormal mode at the time of use of the mechanical property measuring apparatus 100 in a high-pressure hydrogen gas atmosphere will be described. It is assumed that supply of hydrogen gas into the high-pressure vessel 2 has started.

When hydrogen gas leaks from the high-pressure vessel 2, the hydrogen concentration in the nitrogen gas in the thermostat 1 increases. Since the nitrogen gas is always supplied from the nitrogen gas introduction line 5 to the thermostat 1, the nitrogen gas containing hydrogen gas is discharged from the nitrogen gas discharge line 6.
In this case, the tensile test of the test member 44 is continued until the hydrogen gas detection sensor 7 detects a hydrogen gas concentration of 400 ppm. When the hydrogen gas detection sensor 7 detects a hydrogen concentration of 400 ppm (detection process), an alarm is generated by the alarm device 28 (abnormality response process).

  In addition, the on-off valve 19 is forcibly opened by the safety mechanism to release the hydrogen gas inside the high-pressure vessel 2 to the outside (in the atmosphere), the on-off valve 17 is closed, or the compressor 15 is stopped. The operation of the mechanical property measuring apparatus 100 is stopped. Specifically, when the hydrogen gas detection sensor 7 detects a hydrogen concentration of 1000 ppm, the open / close valve 19 is opened and the hydrogen gas in the high-pressure vessel 2 is discharged to the outside through the hydrogen gas discharge pipe 18 (abnormality handling step).

Even when such a hydrogen gas leak occurs, the hydrogen gas leaks into the nitrogen gas filled in the thermostat 1 and not into the air, so there is a risk of explosion or the like. There are few and it is excellent in safety.
As described above, according to the mechanical property measuring apparatus 100 under a high-pressure hydrogen gas atmosphere according to the present embodiment, it is possible to safely measure the mechanical properties of a metal material or the like under a high-pressure hydrogen gas environment.
[Second Embodiment (Reference Example) ]
With reference to FIG. 3, a mechanical property measuring apparatus 100 under a high-pressure hydrogen gas atmosphere according to a second embodiment of the present invention will be described. FIG. 3 is a diagram corresponding to FIG. 2 illustrating the first embodiment.

As shown in FIG. 3, the mechanical property measuring apparatus 100 under a high-pressure hydrogen gas atmosphere according to this embodiment includes a hydrogen gas detection sensor 7, a hydrogen gas detection sensor 30 having a function equivalent to the hydrogen gas detection sensor 7, and At least one of the hydrogen gas detection sensors 31 is provided.
In the mechanical property measuring apparatus 100 under a high-pressure hydrogen gas atmosphere according to the present embodiment, the nitrogen gas is constituted by a discharge system instead of a circulation system, and the hydrogen gas detection sensors 7, 30, 31 are more than the high-pressure vessel 2. It is provided downstream of the nitrogen gas. In addition, since nitrogen gas is always supplied from the nitrogen cylinder 12 through the nitrogen gas introduction pipe 5 to the thermostat 1, a certain amount of nitrogen gas is discharged from the nitrogen gas discharge pipe 6. There is a flow of nitrogen gas going downstream from the left (from left to right in FIG. 3).

Therefore, even if hydrogen gas leaks from the high-pressure vessel 2 into the constant temperature layer 1, leakage of hydrogen gas can be reliably detected in the downstream portion of the high-pressure vessel 2 for nitrogen gas. That is, on the upstream side of the high-pressure vessel 2, hydrogen gas leaked from the high-pressure vessel 2 cannot be detected or is difficult to detect.
As described above, according to the mechanical property measuring apparatus 100 under a high-pressure hydrogen gas atmosphere according to the present embodiment, leakage of hydrogen gas can be reliably detected, and mechanical properties of a metal material or the like in a high-pressure hydrogen environment can be safely obtained. Can be measured.
[Third Embodiment (Example) ]
With reference to FIG. 4, a mechanical property measuring apparatus 100 under a high-pressure hydrogen gas atmosphere according to a third embodiment of the present invention will be described. FIG. 4 is a diagram corresponding to FIGS. 2 and 3 showing the first embodiment and the second embodiment.

As shown in FIG. 4, the mechanical property measuring apparatus 100 under a high-pressure hydrogen gas atmosphere according to the present embodiment is a thermostat 1 having a structure different from the thermostats of the first and second embodiments described above. Is provided.
The thermostat 1 includes a nitrogen gas circulation line 32 that circulates nitrogen gas. The nitrogen gas circulation line 32 includes a circulation mechanism (not shown) (for example, a fan, a motor, a nitrogen tank).

Further, the thermostatic chamber 1 includes a hydrogen gas detection sensor 7, a hydrogen gas detection sensor 30, a hydrogen gas detection sensor 31, a hydrogen gas detection sensor 33 having a function equivalent to these hydrogen gas detection sensors, and a hydrogen gas detection sensor 34. It has at least one of.
In the mechanical property measuring apparatus 100 under a high-pressure hydrogen gas atmosphere according to the present embodiment, the nitrogen gas is constituted not by a discharge system but by a circulation system. Therefore, the hydrogen gas detection sensor is provided at an arbitrary position in the thermostat 1 regardless of the relative position to the high-pressure vessel 2. In other words, it is not limited to the downstream side of the nitrogen gas flow in the high-pressure vessel 2.

  Since nitrogen gas is circulated to the thermostat 1 through the nitrogen gas circulation line 32, a certain amount of nitrogen gas is circulated through the nitrogen gas circulation line 32. When hydrogen gas leaks from the high-pressure vessel 2 into the constant temperature layer 1 in such a state, leakage of the hydrogen gas can be detected at any position inside the constant temperature bath 1 and the nitrogen gas circulation line 32. That is, hydrogen gas leaking from the high-pressure vessel 2 can be detected at any position where nitrogen gas is flowing.

As described above, according to the mechanical property measuring apparatus 100 under the high-pressure hydrogen gas atmosphere according to the present embodiment, the hydrogen gas leakage can be reliably detected without limiting the mounting position of the hydrogen gas detection sensor, It is possible to safely measure the mechanical properties of metal materials and the like in a hydrogen environment.
It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is an overall configuration diagram of a mechanical property measuring apparatus under a high-pressure hydrogen gas atmosphere according to a first embodiment (reference example) of the present invention. It is a figure of the thermostat vicinity of FIG. It is a figure of the thermostat vicinity of the mechanical characteristic measuring apparatus in the high pressure hydrogen gas atmosphere which concerns on 2nd Embodiment (reference example) of this invention. It is a figure of the thermostat vicinity of the mechanical characteristic measuring apparatus in the high pressure hydrogen gas atmosphere which concerns on 3rd Embodiment (Example) of this invention.

DESCRIPTION OF SYMBOLS 1 Constant temperature bath 2 High pressure vessel 3 Stirring fan 4 Medium circulation heater 5 Nitrogen gas introduction line 6 Nitrogen gas discharge line 7 Hydrogen gas detection sensor 8 Test jig 9 Heat medium jacket 10 Hydrogen gas introduction line 11 Pull rod

Claims (3)

A high-pressure vessel in which a test member whose mechanical properties are measured in a high-pressure hydrogen gas atmosphere is disposed;
A thermostatic bath in which nitrogen gas is filled and the high-pressure vessel is disposed;
A circulation mechanism for circulating nitrogen gas inside and outside the thermostat;
A hydrogen gas detector provided in the circulation mechanism;
A medium circulation heater which is arranged on the circulation of nitrogen gas in the thermostat by the circulation mechanism and performs temperature control of the nitrogen gas in the thermostat;
A stirring fan for stirring the nitrogen gas in the thermostat;
An apparatus for measuring mechanical properties in a high-pressure hydrogen gas atmosphere.   The machine under high-pressure hydrogen gas atmosphere according to claim 1, further comprising an alarm transmission mechanism that issues an alarm when the amount of hydrogen gas detected by the hydrogen gas detector is equal to or greater than a predetermined value. Characteristic measuring device. The apparatus according to claim 1 or 2, further comprising a safety mechanism for releasing hydrogen gas inside the high-pressure vessel to the outside when the amount of hydrogen gas detected by the hydrogen gas detector is equal to or greater than a predetermined value. An apparatus for measuring mechanical properties in a high-pressure hydrogen gas atmosphere as described.

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