JP6076166B2 - Combustion and explosion test equipment - Google Patents

Description

  The present invention relates to a combustion / explosion test apparatus for flammable or combustion-supporting low-temperature liquefied gas.

In order to handle flammable or flammable low-temperature liquefied gas safely, it is necessary to measure conditions that cause combustion and explosion, such as measurement of explosion range, surface catalytic effect, minimum ignition energy, and power of explosion. is there.
For tests involving combustion and explosion, there are two methods: an open system and a closed system.

The open system means that the sample to be burned / exploded is released to the atmosphere and ignited, or the sample is sealed in the inner container and ignited, but the inner container is destroyed by damaging at least a part of the inner container by the explosion after ignition. The internal pressure is released to the atmosphere.
Examples of such open system test devices include simple facilities such as “explosion limit region measurement device” in Patent Document 1 and “explosion test device for combustible gas / steam” in Patent Document 2. There is.

  On the other hand, a closed system is one in which an inner container containing a sample such as a mixed gas to be exploded is placed in a pressure-resistant outer container and the pressure of the explosion is not released to the atmosphere. As an example of such a closed system, there is a “pressure vessel and a blast treatment facility including the same” disclosed in Patent Document 3, for example. This Patent Document 3 is a structure in which combustion exhaust gas and shock waves are received in a container and a mechanism for discharging exhaust gases is provided. A pressure-resistant container that can withstand the expected power of explosion and a mechanism for discharging gas and shock waves An apparatus comprising the following is disclosed.

  Patent Documents 1, 2, and 3 all relate to equipment for measuring the explosion limit of a flammable gas at normal temperature, and do not relate to a low-temperature liquefied gas. As a prior art related to an explosive experiment of a low-temperature liquefied gas, there is an example in which an ignition source is installed above a stainless steel container containing a liquid mixture of liquid oxygen and liquid methane, and the combustion mode is examined by igniting explosion. Is disclosed.

JP-A-8145921 JP2010-8135 JP2006-292259 Kanto Shun et al., Abstracts of 2008 Annual Meeting of the Japanese Society for Thermopharmaceutical Science pp.29-30 (2008)

A system containing a combustible low-temperature liquefied gas has a high density of combustible materials and combustion-supporting materials, and emits much greater energy than gas combustion / explosion at room temperature. Therefore, it is desirable to perform the combustion / explosion test for such a system on a small scale as much as possible.
Further, it is preferable that the low temperature liquefied gas combustion / explosion experiment be performed in a closed system. Because it is necessary to prevent intrusion heat from outside air, dissolution of air components, liquefaction, etc. in order to conduct tests involving combustion / explosion in which low-temperature liquefied gas or low-temperature liquefied gas coexists with small-scale and reproducible accuracy, This is because testing in an open system is difficult.
Furthermore, in the ignition test of low temperature liquefied gas at normal temperature or near normal pressure, most of the low temperature liquefied gas is gas at normal temperature and normal pressure. In the liquid phase, the composition changes continuously, and it is difficult to grasp the change numerically.
Therefore, an experiment at an extremely low temperature where the low-temperature liquefied gas becomes liquid is required.
Here, as a system in which a low-temperature liquefied gas or a low-temperature liquefied gas coexists, a mixed system of a combustion-supporting liquefied gas such as liquid oxygen + liquid methane and liquid oxygen + liquid propane and a combustible liquefied gas, and liquid oxygen + solid metal powder And a solid resin and a solid mixture having an active surface, and these are collectively referred to as “a system in which a low-temperature liquefied gas or a low-temperature liquefied gas coexists”.

  As described above, the combustion / explosion test of the system containing the combustible low-temperature liquefied gas is preferably performed on a small scale in a closed system at an extremely low temperature.

In this regard, with respect to the low temperature liquefied gas explosion experiment, the method described in Non-Patent Document 1 is a large-scale, open system and performed at room temperature.
Therefore, according to the method of Non-Patent Document 1, not only the low-temperature liquefied gas as the analyte evaporates at a very high rate due to the intrusion heat of the outside air, but not only the composition for each gas phase and liquid phase can be estimated but also many samples. Therefore, a very large amount of cost was required for the safety environment and safety measures such as a protective wall during the test.
Further, in the case of the method as described in Non-Patent Document 1, it is necessary to use a large amount of sample in order to reduce the influence of evaporation diffusion and intrusion heat. A huge cost is required.

  As described above, there are various prior art technologies related to combustion / explosion testing equipment, but in systems that contain flammable low-temperature liquefied gas, an apparatus that can repeatedly and safely perform tests involving combustion / explosion is possible. It has not been proposed, and the development of such a device has been desired.

(1) A combustion / explosion test apparatus according to the present invention is an apparatus for performing a low temperature liquefied gas combustion / explosion test,
A pressure-resistant container that is cooled from outside and evacuated inside;
A low-temperature liquefied gas container that is disposed inside the pressure-resistant container and that contains a low-temperature liquefied gas as a specimen;
A container holding mechanism for holding the low-temperature liquefied gas container in the pressure-resistant container;
A pressure release mechanism for discharging the combustion gas generated when the low-temperature liquefied gas is burned / exploded to the outside of the system, provided at the upper part of the pressure vessel,
The pressure release mechanism closes an opening provided in the upper part of the pressure vessel and is deformed when the valve body is moved upward by combustion / explosion of the low-temperature liquefied gas, and a valve body provided to be movable upward. And a cushioning material that absorbs the moving energy of the valve body.

(2) Further, in the above (1), a liner made of copper or a copper alloy is provided in the pressure vessel so as not to contact the upper portion of the pressure vessel and the inner wall surface. It is.

(3) Further, in the above (1) or (2), the cushioning material is composed of a plurality of members, and the members are arranged at a position corresponding to the outer peripheral portion of the valve body. Is high, and the height of what is arranged inward is low.

(4) Moreover, in the thing in any one of said (1) thru | or (3), the said buffer material consists of aluminum, lead, copper, or these alloys, It is characterized by the above-mentioned.

  In the present invention, a pressure-resistant container that is cooled from the outside and evacuated inside, a low-temperature liquefied gas container that is disposed inside the pressure-resistant container and that contains a low-temperature liquefied gas that is a subject, and the low-temperature liquefied gas container And a pressure release mechanism for discharging combustion gas generated when the low-temperature liquefied gas is burned / exploded to the outside of the system. The pressure release mechanism closes an opening provided in the upper part of the pressure vessel and is movably provided upward, and collides with the valve body when the valve body moves up. By providing a cushioning material that deforms, the valve body moves up and deforms the cushioning material when the low-temperature liquefied gas in the low-temperature liquefied gas container is burned or exploded, so that the energy from the combustion or explosion is increased. Absorbed and caused by explosion Thereby preventing damage to the device due to pressure and impact occurs, it is possible to prevent the fire spreading to the pressure vessel and ancillary equipment. As a result, ignition, combustion, and explosion tests can be performed in a small-scale closed system in the presence of low-temperature liquefied gas and low-temperature liquefied gas, and repeated tests are possible.

It is explanatory drawing explaining the whole structure of the combustion / explosion test apparatus 1 which concerns on embodiment of this invention, Comprising: It is a disassembled perspective view including a partial cross section. It is explanatory drawing explaining the pressure | voltage resistant container of the combustion / explosion test apparatus 1 which concerns on embodiment of this invention. It is explanatory drawing explaining the internal structure of the pressure vessel of the combustion / explosion test apparatus 1 which concerns on embodiment of this invention, Comprising: The longitudinal cross-section is illustrated It is explanatory drawing explaining the low temperature liquefied gas container arrange | positioned in the pressure-resistant container of the combustion / explosion test apparatus 1 which concerns on embodiment of this invention. It is explanatory drawing explaining the holding mechanism of the low-temperature liquefied gas container of the combustion / explosion test apparatus 1 which concerns on embodiment of this invention. It is explanatory drawing explaining the arrangement | positioning state of the low temperature liquefied gas container of the combustion / explosion test apparatus 1 which concerns on embodiment of this invention. It is explanatory drawing explaining the pressure release mechanism of the combustion / explosion test apparatus 1 which concerns on embodiment of this invention (the 1). It is explanatory drawing explaining the pressure release mechanism of the combustion / explosion test apparatus 1 which concerns on embodiment of this invention (the 2). It is explanatory drawing explaining the other aspect of the pressure release mechanism of the combustion / explosion test apparatus 1 which concerns on embodiment of this invention. It is explanatory drawing explaining operation | movement of the pressure release mechanism of the combustion / explosion test apparatus 1 which concerns on embodiment of this invention.

As shown in FIG. 1, a combustion / explosion test apparatus 1 according to an embodiment of the present invention is installed in an outer container 3 and the outer container 3, cooled from the outside and evacuated inside. A pressure vessel 5, a low-temperature liquefied gas container 7 (see FIG. 4) that is disposed inside the pressure-resistant vessel 5 and that contains a low-temperature liquefied gas that is a subject, and a container holder that holds the low-temperature liquefied gas container 7 in the pressure-resistant vessel 5. A mechanism 9 (see FIG. 5), a pressure release mechanism 11 provided at the top of the pressure vessel 5 for discharging the combustion gas generated when the low-temperature liquefied gas is burned and exploded, and a container holding mechanism. 9, a liquefaction cooling unit 13 for cooling the low-temperature liquefied gas container 7, a pressure-resistant container cooling unit 15 for cooling the pressure-resistant container 5, and a refrigerator that cools the liquefaction cooling unit 13 and the pressure-resistant container cooling unit 15. 16 and gas for supplying gas to the low temperature liquefied gas container 7 And a vessel 17.
Hereinafter, each configuration will be described in detail.

<Outer container>
The outer container 3 has a circular bottom plate portion 3a, a cylindrical side wall portion 3b, and a top plate portion 3c provided with an opening 3d in which the pressure-resistant container 5 is installed. The inside of the outer container 3 is vacuum insulated.

<Pressure vessel>
As shown in FIGS. 1 to 3, the pressure vessel 5 includes a pressure vessel main body 31 formed of a bottomed cylinder, a lid 33 (see FIG. 1) that covers the opening of the pressure vessel main body 31, and a pressure vessel main body 31. A liner 35 (see FIG. 3) that covers the inner wall surface of the container and a solid heat conducting portion 37 (see FIG. 3) provided on the inner bottom of the pressure vessel main body 31.
Each structure of the pressure vessel 5 will be described in detail.

≪Pressure vessel body≫
The pressure vessel main body 31 is formed of a bottomed cylinder, and has a flange portion 31a at the upper end. The pressure vessel main body 31 is made of a material such as stainless steel, which has high strength and is easy to process and hardly conducts heat.
The pressure vessel main body 31 is configured to be evacuated by a vacuum pump (not shown). Specifically, for example, an oil rotary pump or the like is used as a vacuum pump, and the pressure vessel main body 31 is evacuated to about 1 × 10 ⁻¹ Pa through a pipe penetrating the lid 33.

When the subject burns or explodes, the low-temperature liquefied gas container 7 is damaged due to an explosion pressure of several GPa inside, but the pressure and impact applied to the pressure-resistant container body 31 are not separated from the low-temperature liquefied gas container 7. It is reduced to about several MPa by providing. Therefore, the pressure strength of the pressure vessel main body 31 is sufficient to that extent.
The pressure vessel determines the required pressure resistance from the estimated explosion pressure expected when the sample burns or explodes.
Many estimation methods including generated gas and shock wave in case of explosion of liquid or solid have already been reported. These are also applicable to general liquefied oxygen and combustible liquefied gas mixtures, and can be estimated. From this estimated value, it is possible to calculate the pressure resistance of the container that is not likely to be damaged when the liquefied combustion-supporting gas and the liquefied combustible gas mixture are ignited or exploded in a closed system. References include AGSTRENG et al., Journal of Chemical and Engineering Data, Vol. 4, No. 2, p. 127-April (1959).

  Since the operation of the pressure release mechanism 11 (details will be described later) may not be in time when detonation occurs, the pressure resistance of the pressure vessel body 31 is mutually safe by setting the pressure resistance including the shock wave at the time of detonation. Can be secured more reliably.

≪Cover body≫
As shown in FIG. 1, the lid 33 has a plate shape and is installed so as to cover the opening of the pressure vessel main body 31.
The lid 33 is provided with an opening 33a that penetrates in the thickness direction and communicates with the inside of the pressure vessel main body 31. The opening 33a corresponds to an opening provided on the pressure vessel 5 of the present invention. . The valve element 19 is inserted into the opening 33a so that the opening 33a can be closed.
A groove portion 33b (see FIG. 8) is provided around the opening portion 33a along the edge of the opening portion 33a. The groove portion 33b has an O− for enhancing the sealing performance between the valve body 19 and the lid body 33. Ring seals can be installed.

≪Liner≫
The liner 35 is formed of a material having excellent thermal conductivity and low combustibility even when exposed to oxygen gas, for example, copper or a copper alloy such as brass. The reason for this will be described below.
In a test of a system in which a low-temperature liquefied gas and a low-temperature liquefied gas coexist, depending on the test conditions, a test of a system in which a large amount of a combustion-supporting liquefied gas is present is also performed. At that time, the combustion-supporting gas that does not react with the combustible liquefied gas may cause a combustion reaction with surrounding materials. In particular, stainless steel and iron cause an explosive combustion reaction in an oxygen gas atmosphere even at low temperatures. Therefore, if the pressure vessel 5 in direct contact with the combustion gas is made of these materials, there is a possibility of spreading to the pressure vessel 5. is there. As a countermeasure, a liner 35 of copper or copper alloy (brass) is installed inside the pressure vessel 5. Copper or brass has very good heat conduction and does not accumulate heat due to explosion locally. Therefore, there is no spread of fire to copper and brass, and there is no possibility of spreading to the pressure vessel 5.

  The liner 35 may be punched metal, and is preferably not in direct contact with the inner wall of the pressure vessel main body 31 and the lid body 33 but in direct contact with the cold base 37a (see FIG. 3) or the base plate 61 (see FIG. 5). . When the liner 35 is in contact with the inner wall of the pressure vessel main body 31 and the lid 33, a heat transfer route is formed from the inner wall surface of the pressure vessel main body 31 and the lid 33 to the cold base 37a and the base plate 61 to reduce the cooling effect. . Further, since the liner 35 can be brought to substantially the same temperature as the cold base 37a or the base plate 61 by coming into contact with the cold base 37a or the base plate 61, the effect of reducing the radiant heat to the low temperature liquefied gas container 7 and the container holding mechanism 9 is achieved. Can be expected.

≪Solid heat conduction part≫
The solid heat conducting unit 37 is provided between the low temperature liquefied gas container 7 and the liquefied cooling unit 13 (see FIG. 6), and conducts the cold heat of the liquefied cooling unit 13 cooled by the refrigerator 16 to the low temperature liquefied gas container 7. Is for.
As shown in FIG. 3, the solid heat conducting unit 37 includes a cold base 37 a that covers the bottom of the pressure vessel main body 31 and a rod-like cold rod 37 b that protrudes downward from the bottom of the pressure vessel main body 31. The solid heat conducting portion 37 is preferably made of the same material as the liner 35.
As shown in FIG. 1, the liquefying and cooling unit 13 is connected to the cold rod 37b so that cold heat can be conducted.
The solid heat conducting portion 37 is fixed to the pressure vessel main body 31 by a method in which the dissimilar metal is firmly fixed even at a low temperature such as brazing or a metal C ring. By doing so, it is possible to suppress the occurrence of gas leakage or material cracking even during heat shrinkage.

<Low temperature liquefied gas container>
As shown in FIG. 4, the low-temperature liquefied gas container 7 has a bottomed cylindrical shape and seals and holds the low-temperature liquefied gas of the subject.
A block 53 is provided on the open end side of the low-temperature liquefied gas container 7, and a gas introduction pipe 55 for supplying gas from the gas container 17 is connected to the block 53. A pair of discharge electrodes 57 for igniting the subject are inserted on the side surfaces of the block portion 53.
The low-temperature liquefied gas container 7 is preferably held by the container holding mechanism 9 as shown in FIG. 5 and installed at the center of the pressure-resistant container 5 as shown in FIG.
When the object is ignited using the discharge electrode 57 or the like, the low-temperature liquefied gas container 7 is damaged due to combustion or explosion of the object.

<Container holding mechanism>
As shown in FIG. 5, the container holding mechanism 9 includes a base plate 61 that is cooled by being in contact with the cold base 37 a of the solid heat conducting unit 37, and a pair of inverted L-shapes that are erected from the base plate 61. The holding arm 63 is disposed so that the tip 63a faces each other.
As shown in FIG. 5, the holding arms 63 are configured such that the tip portions 63 a are connected to each other with a bolt 65, and the gap between the tip portions 63 a can be adjusted by the bolt 65. For this reason, if the block part 53 is arrange | positioned between the front-end | tip parts 63a and the volt | bolt 65 is tightened, the block part 53 can be clamped and hold | maintained. (See FIG. 6).
As shown in FIG. 6, the low-temperature liquefied gas container 7 is disposed in the pressure-resistant container body 31 by installing the container holding mechanism 9 on the cold base 37 a in the pressure-resistant container body 31. The The low-temperature liquefied gas container 7 is cooled from the cold rod 37 b of the solid heat conducting unit 37 through the cold base 37 a, the base plate 61, and the holding arm 63.

<Pressure release mechanism>
The pressure release mechanism 11 will be described in detail based on FIG. 1, FIG. 7, and FIG. FIG. 7 illustrates a part of the pressure release mechanism 11 and illustrates a state viewed from below. FIG. 8 illustrates a longitudinal section in a state where the valve body 19 of FIG. 7 has moved upward.

  As shown in FIGS. 1, 7 and 8, the pressure release mechanism 11 closes the opening 33 a of the lid 33 to keep the inside of the pressure-resistant container 5 in a vacuum and is provided so as to be movable upward. The anti-scattering member 41 (see FIG. 1), which has a bottomed cylindrical shape and covers the upper side of the lid 33 to form a space in which the valve element 19 can move up, is installed in the anti-scattering member 41 and the valve element 19 A cushioning material (a cushioning material (high) 21 and a cushioning material (low) 23) that collides with the valve body 19 and deforms when the valve moves upward, and a valve body guide 43 that guides the movement of the valve body 19. Yes.

≪Valve≫
As shown in FIG. 1, the valve body 19 has a cylinder part 19a and a disk part 19b provided at the upper end of the cylinder part 19a and projecting outward from the cylinder part 19a. The diameter of the cylindrical portion 19a is set to a diameter that can be inserted into the opening 33a of the lid 33 of the pressure vessel 5.
The valve body 19 is preferably formed of a relatively light metal such as aluminum.
As described above, the groove 33b is provided in the lid 33, and by installing an O-ring seal or the like, the pressure between the valve body 19 and the lid 33 is sealed by the dead weight of the valve body 19. The vacuum in 5 is maintained.
A coil spring 45 may be installed between the upper part of the valve body 19 and the scattering prevention member 41 so as to press the valve body 19 toward the lid 33 side. For example, as shown in FIG. 9, the coil spring 45 is disposed between the center of the pressure release mechanism disk portion 19 b and the anti-scattering member 41, and the buffer material (high) 21 is disposed outside the coil spring 45. The cushioning material (low) 23 may be disposed inside 45.

≪Buffer material (high) and buffer material (low) ≫
A plurality of cushioning materials (high) 21 and cushioning materials (low) 23 are installed on the surface of the anti-scattering member 41 that faces the valve element 19, and energy that causes the valve element 19 to collide with the anti-scattering member 41 during combustion / explosion is obtained. It absorbs by compressing and deforming itself and prevents damage to the valve body 19. Therefore, a relatively soft material such as aluminum, lead, copper, or an alloy thereof is suitable, and a tapered shape such as a cone or a pyramid is preferable.

The cushioning material (high) 21 is set to be higher than the cushioning material (low) 23, the cushioning material (high) 21 is disposed on the outer peripheral portion, and the cushioning material (low) 23 is disposed inward. The reason for this arrangement will be described below.
The valve element 19 of the pressure release mechanism 11 moves upward in response to the blast and shock wave during combustion / explosion, but does not always rise while maintaining the closed position (horizontal position). ) As shown in ()). In this case, the disc part 19b of the valve body 19 first collides with the cushioning material (high) 21 arranged on the outer peripheral part. The top of the cushioning material having a low compressive strength is gradually compressed and destroyed by the collision, but the strength increases as it is deformed. Therefore, as shown in FIG. 10B, the posture is corrected so that the valve body 19 is horizontal. . If the height of the cushioning material is uniform, as shown in FIG. 10 (a), the disk portion 19b collides with the cushioning material on the inside immediately after colliding with the cushioning material on the outer periphery. Therefore, the posture correction effect of the valve body 19 is reduced. That is, the reason why the height of the cushioning material disposed inward is set low is to prevent the cushioning material from interfering with the posture correction of the valve body 19.

However, since the collision energy of the valve body 19 is very large, it is desirable to receive the valve body 19 with as much cushioning material as possible.
For this reason, a buffer material (low) 23 is arranged inside the scattering prevention member 41 so that the force against compression is increased as the breakage proceeds due to the collision of the valve body 19.
That is, the buffer material (high) 21 has a role of correcting the posture of the valve body 19 in addition to absorbing the collision energy, and the buffer material (low) 23 receives the collision of the valve body 19. It has the role of absorbing collision energy.

In addition, you may make it install the shock absorbing material of a material from which compressive strength differs in an outer peripheral part and an inner side. In this case, the material installed on the outer periphery uses a material having a lower compressive strength than that installed on the center side.
In the above description, the buffer material (high) 21 and the buffer material (low) 23 are provided on the anti-scattering member 41. However, the buffer material (high) 21 and the buffer material (low) 23 are the valve body. 19 and the anti-scattering member 41, for example, may be provided upright on the upper surface of the disc portion 19b of the valve body 19.

≪Valve guide≫
The valve body guide 43 has a cylindrical shape provided on the surface of the scattering prevention member 41 on the valve body 19 side, and the disc portion 19b of the valve body 19 can be inserted inside.
The valve body guide 43 functions as a guide when the valve body 19 ascends, and prevents the broken buffer material from scattering.

An example of a method for performing a combustion / explosion test using the combustion / explosion test apparatus 1 according to the present embodiment configured as described above will be described together with the operation of the pressure release mechanism 11.
First, the vacuum heat insulating layer between the outer vessel 3 and the pressure vessel 5 is evacuated and the temperature of the outer surface of the low temperature liquefied gas vessel 7 is lowered. In this state, a gas (for example, methane gas or oxygen) is quantitatively introduced and held until the temperature and pressure in the low temperature liquefied gas container 7 are in equilibrium.

  Next, a current is applied to the discharge electrode 57 to explode the subject. Then, the valve element 19 is instantaneously moved upward by the combustion gas and the shock wave and collides with the buffer material (high) 21 and the buffer material (low) 23 of the anti-scattering member 41 to absorb energy. At this time, even if the valve body 19 tilts and rises (thick arrow in FIG. 10A), the trajectory is corrected in the direction of gradually rising vertically by colliding with the cushioning material (high) 21 (see FIG. 10). 10 (b), a thick arrow), it is possible to collide with more cushioning material (high) 21 and cushioning material (low) 23. Therefore, the collision of the valve body 19 is received evenly and effectively, and the energy is effectively absorbed, and damage to the valve body 19 and the pressure vessel 5 is prevented.

  As described above, in the present embodiment, the pressure release mechanism 11 is provided, and when the low-temperature liquefied gas in the low-temperature liquefied gas container 7 is combusted / exploded, the valve body 19 moves up and the buffer materials 21, 23 Since the energy due to combustion / explosion is absorbed by giving deformation to the apparatus, it is possible to prevent damage to the apparatus due to the pressure and impact generated by the explosion, and to prevent the spread of fire to the pressure vessel and incidental equipment. As a result, ignition, combustion, and explosion tests can be performed in a small-scale closed system in the presence of low-temperature liquefied gas and low-temperature liquefied gas, and repeated tests are possible.

  If the strength of the pressure vessel 5 is sufficient to withstand the pressure and shock wave when the low-temperature liquefied gas is burned / exploded, the vessel will become thicker and the heat capacity will increase, so the pressure vessel 5 will be kept at a low temperature. Although the capacity of the refrigerator for maintaining is increased, in the present invention, since the pressure release mechanism 11 is provided, the wall thickness of the container can be reduced as compared with the case without this. As a result, a small refrigerator can be used, and a small-scale refrigerator can also be used in this respect.

The effect of the pressure release mechanism 11 in the combustion / explosion test by the combustion / explosion test apparatus 1 of the present invention will be described based on specific examples.
In this embodiment, the pressure vessel 5 has an internal volume of about 5 liters, and it is assumed that about 3 g of the CH ₄ + O ₂ mixed solution will explode in the vessel, and the maximum pressure at the time of explosion is 2.5. Estimated to be MPaG and created a container pressure resistance.
The low-temperature liquefied gas container 7 was made of copper in order to make the container wall as thin as possible and to reduce the heat transfer resistance as much as possible so that it could be easily broken during an explosion. Further, the container holding mechanism 9 is provided on the heat transfer plate at the bottom of the pressure vessel 5 so that the low temperature liquefied gas vessel 7 can be installed as close to the center of the pressure vessel 5 as possible.
Moreover, while providing the vacuum heat insulation layer between the outer container 3 and the pressure vessel 5, the inside of the pressure vessel 5 was also kept in a vacuum state.

In addition, 27 scattering materials (high) 21 made of aluminum and having a conical height of 18 mm and 11 cushioning materials (low) 23 having the same cone height of 8 mm are prepared for the scattering prevention member 41, and these are adhesives. It was attached simply.
The valve body 19 was made of aluminum, and was sealed with a pressure vessel 5 having its own weight and vacuum by an O-ring.
The liner 35 of the pressure vessel 5 is made of pure copper having a thickness of 2 mm, is punched with an opening ratio of 20% and a diameter of 2 mm, and is placed on the cold base 37a in the pressure vessel 5 so that the gap with the inner wall of the pressure vessel 5 is 1-2 mm. Installed with a guide.

After assembling each part, the vacuum insulation layer between the outer container 3 and the pressure vessel 5 is evacuated to 1 × 10 ⁻³ Pa or less so that the temperature of the outer surface of the low temperature liquefied gas container 7 is 85K or less. Controlled. In this state, oxygen gas was quantitatively introduced into the low-temperature liquefied gas container 7 which was a vacuum, and kept until the temperature and pressure in the low-temperature liquefied gas container 7 were in equilibrium. Further, methane gas was introduced and kept in a state of sufficient equilibrium as with oxygen introduction.
At this time, the amount of methane and oxygen introduced was CH ₄ : O ₂ = 0.03 mol: 0.07 mol. The pressure in the liquefaction vessel when it was sufficiently equilibrated was 90 kPa (abs).

In this state, when an electric current was applied to the discharge electrode 57 attached to the liquefying container, an explosion occurred in the low temperature liquefied gas container 7, and the low temperature liquefied gas container 7 was damaged. The maximum discharge energy at this time was 3 mJ.
As a result, damage was observed in the cryogenic liquefied gas container 7, the buffer material (high) 21, the buffer material (low) 23, the liner 35, and a part of the holding arm 63, but no damage was observed in the pressure vessel 5 and the like. It was confirmed that sufficient strength was maintained for repeated tests by replacing damaged products.
From the above, it was confirmed that if the combustion / explosion test apparatus 1 is used, the combustion / explosion test in a system containing a combustible low-temperature liquefied gas can be repeatedly performed with high accuracy.

DESCRIPTION OF SYMBOLS 1 Combustion / explosion test apparatus 3 Outer container 3a Bottom part 3b Side wall part 3c Top plate part 3d Opening part 5 Pressure-resistant container 7 Low temperature liquefied gas container 9 Container holding mechanism 11 Pressure release mechanism 13 Liquefaction cooling part 15 Intermediate cooling part 16 Refrigerating machine 17 Gas Container 19 Valve body 19a Tube portion 19b Disc portion 21 Buffer material (high)
23 cushioning material (low)
31 pressure-resistant vessel body 31a flange portion 33 lid 33a opening 33b groove portion 35 liner 37 solid heat conducting portion 37a cold base 37b cold rod 41 scattering prevention member 43 valve element guide 45 coil spring 53 block portion 55 gas introduction tube 57 discharge electrode 61 base Plate 63 Holding arm 63a Tip portion 65 Bolt

Claims (4)

An apparatus for conducting a combustion / explosion test of a low-temperature liquefied gas,
A pressure-resistant container that is cooled from outside and evacuated inside, a low-temperature liquefied gas container that is disposed inside the pressure-resistant container and that contains a low-temperature liquefied gas that is a subject, and the low-temperature liquefied gas container is placed in the pressure-resistant container And a pressure release mechanism for discharging the combustion gas generated when the low-temperature liquefied gas is burned / exploded to the outside of the system. The pressure release mechanism closes the opening provided in the upper part of the pressure vessel and is deformed when the valve body is moved upward by combustion / explosion of the low-temperature liquefied gas. A combustion / explosion test apparatus comprising a buffer material that absorbs the movement energy of the valve body.   The combustion / explosion test apparatus according to claim 1, wherein a liner made of copper or a copper alloy is provided inside the pressure vessel so as not to contact the upper portion of the pressure vessel and the inner wall surface. The cushioning material is composed of a plurality of members, and the height of the members disposed at positions corresponding to the outer peripheral portion of the valve body is high, and the height of the members disposed inward is low. The combustion / explosion test apparatus according to claim 1 or 2, characterized by the above.   The combustion / explosion test apparatus according to any one of claims 1 to 3, wherein the buffer material is made of aluminum, lead, copper, or an alloy thereof.

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