JPH0442757Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to an apparatus for detecting leakage of liquefied natural gas and releasing the leaked liquefied natural gas to a safe location.

BACKGROUND ART In typical prior art, one end of a pipe made of a material such as vinyl is placed near a flange joint of the pipe that penetrates the cold insulation material covering the pipe line for transporting liquefied natural gas, and the pipe is A portable gas detector can be connected to the other end. A portable gas detector detects whether a leak is occurring, for example, once a month.

Problems to be Solved by the Invention With such prior art, it is not possible to constantly detect a leakage state, and therefore it is not possible to take immediate countermeasures even if a leakage occurs at night. Also,
The pipe is open to the atmosphere when a portable gas detector is not connected, and there is a risk of explosion if gas leaks. Also, rainwater may enter through the connection port and freeze inside the pipe. In this case, it becomes impossible to perform gas detection.

An object of the present invention is to provide a leakage detection device that can always reliably detect leaked liquefied natural gas and, when gas is leaking, discharge it to a safe location.

Means for Solving the Problems The present invention is a leakage detection valve that includes a spring made of a shape memory alloy that deforms depending on the temperature of leaked liquefied natural gas, and a spring chamber that accommodates the spring that deforms depending on the temperature of leaked liquefied natural gas. A partition member made of a thermally conductive material that partitions the inlet, a working fluid source that supplies a working fluid, an alarm means actuated by the working fluid, and a spring interposed between the working fluid source and the alarm means. and a leakage detection valve having a valve means that becomes open when the leakage liquefied natural gas is deformed; and a leakage natural gas relief valve including a spring made of a shape memory alloy that deforms depending on the temperature of the leakage liquefied natural gas. This is a device to detect leaked liquefied natural gas.

Effect According to the present invention, the low-temperature leaked liquefied natural gas to be detected by the leak detection valve contacts the partition member made of a thermally conductive material and lowers the temperature of this partition member. As a result, the temperature of the spring made of a shape memory alloy that contacts the partition member decreases and deforms. Therefore, the valve means is in an open state.
Thereby, the working fluid from the working fluid source is directed to the alarm means via the valve means without mixing with the leaked liquefied natural gas. Leakage detection can be performed by activating this alarm means.

In addition, the liquefied natural gas leaking from the relief valve directly contacts the spring made of the shape memory alloy, lowers its temperature, and deforms. Therefore, the relief valve is opened and the leaked gas can be quickly released to a safe location.

Embodiment FIG. 1 is an overall system diagram of an embodiment of the present invention. A cold insulating material 2 is provided around the outer periphery of the liquefied natural gas transport pipe 1. This liquefied natural gas transport pipe 1 is
They are connected by a flange joint 3. Since there is a high risk of leakage of liquefied natural gas from the flange joint 3, a cold insulation material 2 is placed near the flange joint 3.
It is surrounded by a cover 4 made of a material such as metal and hermetically sealed. In this way, flange joint 3
The liquefied natural gas leaked from inside the cover 4 flows out into the pipe line 5 connected to the cover 4.
A leak detection valve 6 and a pipe line 5a are connected to the pipe line 5, and a relief valve 7 and a pipe line 5b for guiding the liquefied natural gas from the relief valve 7 to a safe place are connected to the pipe line 5a in this order. provided. By the action of the leakage detection valve 6, compressed air from the air pressure source 21 is supplied to the air horn 8, which is an alarm means, through the pipe line 27 and is blown, thereby detecting the occurrence of a leakage.

FIG. 2 is a sectional view of the leak detection valve 6 used in the present invention. A flange 9 is fixed to the end of the conduit 5. This flange 9 is connected to a flange 11 provided on a valve box 10. In the valve box 10, a partition member 12 is screwed near the flange 11.

FIG. 3 is an exploded perspective view of the partition member 12 and its vicinity. The partition member 12 is made of metal, which is a thermally conductive material, and includes an external threaded portion 13 and a thin plate-like spring receiving portion 14, and has a recess 15 that is open to the pipe line 5 side. The external threaded portion 13 is connected to the valve body 1
It is screwed into the internal thread 16 formed at 0. In this way, the partition member 12 airtightly partitions the pipe line 5 side from the spring chamber 17 formed in the valve box 10.

A valve seat member 18 is also screwed onto the valve body 10 on the opposite side of the flange 11 (left side in FIG. 2). This valve seat member 18 has a valve hole 19 and a valve seat 20. Compressed air, which is a working fluid, is supplied to the valve hole 19 from an air pressure source 21 through an inlet 22 . A flat valve body 23 is seated on the valve seat 20 and the valve hole 19 is opened.
can be closed. A right cylindrical guide tube 24 extending toward the partition member 12 is connected to the valve body 23 . This guide tube 24 defines the spring chamber 17 . The coil spring 25 is partially inserted into the guide tube 24 within the spring chamber 17 and comes into contact with the spring receiving portion 14 of the partition member 12 . A gland seal 76 surrounding the guide tube 24 is attached by a seal presser member 77.

The spring 25 is made of a shape memory alloy, and is cooled by liquefied natural gas via the partition member 14, and its strength decreases and contracts at a specific temperature. When the temperature reaches a certain temperature or higher, the spring 25 expands again to its original memorized shape. When the spring 25 is cooled by liquefied natural gas and contracts at a certain temperature, the compressed air displaces the valve body 23 to the right in FIG.
There is a difficulty between the valve body 23 and the valve body 23. Compressed air is thereby discharged from the outlet 26 of the valve body 10. The compressed air from the outlet 26 is led to the air horn 8 through the pipe line 27, and the air horn 8 blows. spring 25
is at a temperature higher than a certain temperature and is therefore elongated, the valve body 23 is explosively seated on the valve seat 20 by the spring force of the spring 25.
Compressed air therefore does not flow from the valve hole 19 to the outlet 26.

Flange joint 3 of pipe 1 for transporting liquefied natural gas
When a leak occurs from inside the cover 4, the liquefied natural gas from inside the cover 4 flows from the pipe line 5 into the recess 15 in the partition member 12 of the leak detection valve 6. As a result, the spring receiving portion 14 of the partition member 12 is cooled. Therefore, the spring 2 made of shape memory alloy
5 is cooled and contracts, and the valve body 23 is separated from the valve seat 20. In this way, the air horn 8 is blown by compressed air as described above. In this way, leakage of liquefied natural gas can be detected at all times. The leak detection valve 6 is connected to the pipe line 5, so there is no risk of rainwater entering into the pipe line 5. Therefore, leakage can be detected reliably.

Further, since the leaked liquefied natural gas cools the spring 25 made of a shape memory alloy through the partition member 14, the leaked liquefied natural gas and compressed air do not mix to produce an explosive mixed gas. Since the leaked liquefied natural gas is released to a safe place from the relief valve 7, which will be described later, the pipes 5 and 5a including the leak detection valve 6 are not pressurized.

FIG. 4 is a sectional view of another embodiment 6a of the leak detection valve 6 used in the present invention. In this embodiment, parts corresponding to those in the previous embodiment are given the same reference numerals. The valve body 3 is inserted into the guide hole 31 of the valve box 30.
A guide tube 33 in the form of a right cylinder with a bottom and connected to the tube 2 is inserted therethrough.

5 is an exploded perspective view of the valve body 32 and its surroundings. The valve body 30 has an internal thread 34 on the flange 11 side.
The inner thread 34 is threadedly engaged with the outer thread 36 of the partition member 35.
The guide tube 35 is made of a metal having thermal conductivity, and the tube portion 37 that enters the pipe 5 is made thin-walled.
The spring receiving member 40 is inserted into the cylindrical portion 37 so as to be displaceable in the axial direction. An external thread 39 is formed so as to be connected to the cylindrical portion 37 and extend toward the pipeline 5. An internal thread 41 of the spring receiving member 40 is screwed into the external thread 39.
A threaded portion 43 connected to a rod-shaped projection 42 is inserted into the rod-shaped projection 42. A nut 44 is screwed into the threaded portion 43.
As a result, the projection 42 is fixed to the spring receiving member 40. The projection 42 enters the guide hole 33 of the partition member 35. A gland seal 78 surrounding the guide cylinder 33 is attached by a seal pressing member 79.

The coil spring 45 surrounds the protrusion 42, and one end thereof can come into contact with the bottom 46 of the guide tube 33.
The other end can abut the spring receiving member 40 . The spring 45 is made of a shape memory alloy, and is cooled by liquefied natural gas, and its strength decreases and contracts at a certain temperature, and is in an expanded state at a higher temperature. The valve body 32 can be seated on the valve seat 20, thereby blocking compressed air from the inlet 22 through the valve hole 19. Valve body 32
When the valve is away from the valve seat 20, the compressed air from the inlet 22 is discharged to the outlet 26 and is thereby guided to the air horn 8 via the conduit 27 (see FIG. 1). It is blown.

When liquefied natural gas leaks from the flange joint 3 of the liquefied natural gas transport pipe 1, the leaked liquefied natural gas is guided from the pipe line 5 to the leak detection valve 6a. As a result, the cylindrical portion 3 of the partition member 35
7, the spring receiving member 40, etc. are cooled, and the spring 45 contracts accordingly. Due to this, the valve body 32
And the guide tube 33 is allowed to be displaced to the right in FIG. Thus, compressed air from inlet 22 is directed via outlet 26 to air horn 8 as previously described.

In this example as well, leaked liquefied natural gas flows through the partition member 35 to the spring 45 made of shape memory alloy.
The leaked liquefied natural gas and compressed air will not mix and create an explosive gas mixture. As in the previous example, the piping 5, 5a including the leak detection valve 6a is not pressurized by the leaked liquefied natural gas.

When there is no liquefied natural gas leak,
The spring force of the spring 45 causes the valve body 32 to sit explosively on the valve seat 20, so that the compressed air from the inlet 22 is not guided from the outlet 26 to the air horn 8.

FIG. 6 is a longitudinal sectional view of the relief valve 7 used in the present invention. A flange 51 of the valve box 50 is connected to the conduit 5a. A flange 52 is provided on the opposite side of the valve box 50 from the flange 51 (lower side in FIG. 6), and a joint member 53 is connected to this flange 52. The coupling member 53 is connected to the conduit 5b.
An inlet 54 is formed in the valve box 50 into which leaked liquefied natural gas from the pipe line 5a flows.
A central hole 55 communicates with the. An internal thread 56 is formed at the lower end of the central hole 55 in FIG.
This inner thread 56 has an outer thread 58 of the valve seat member 57.
are screwed together. A valve chamber 59 is formed in the valve box 50 so as to be continuous with the central hole 55 . The inlet 54, the central hole 55, and the valve chamber 59 are formed to have larger inner diameters in this order. The valve chamber 59 is connected to an outlet 60 formed in the joint member 53. The valve seat member 57 has an external thread 5
The valve seat 62 has a mounting portion 61 with a numeral 8 engraved thereon, and a valve seat portion 62 that is connected to the mounting portion 61 and is located within the valve chamber 59 . A valve seat 64 provided with a seal member 63 is formed in the valve seat portion 62 . The valve body 65 has a flat disk shape and can be seated on the valve seat 64 to close the valve. A valve rod 66 is connected to the valve body 65 . A support portion 67 is formed in the valve seat portion 62 of the valve seat member 57 . The valve rod 66 is inserted through the support portion 67 so that the valve rod 66 can be displaced in its axial direction (vertical direction in FIG. 6). valve stem 66
An external thread 69 is cut into the end of the holder. A bottom 71 of a bottomed cylindrical spring receiving member 70 is inserted into the end of the valve stem 66, and this bottom 71 is connected to the threaded portion 6.
It is fixed to the valve stem 66 by a nut 72 that is screwed into the valve stem 66 .

A coiled first spring 73 made of a shape memory alloy is partially accommodated within the spring receiving member 70 . This spring 73 contacts the support portion 67 . The support part 67 has the entrance 54 side of the central hole 55 and the valve seat 6.
A communication hole 74 communicating with the fourth side is formed.

The first spring 73 is made of a shape memory alloy as described above, and when cooled by liquefied natural gas, its strength decreases and it contracts at a specific temperature. The first spring 73 is expanded when the temperature is above a specific temperature.

A second spring 75 is formed between the valve body 65 and the support portion 67 of the valve seat member 57. First spring 73
When the valve body 65 is extended, the valve body 65 is moved to the valve seat 64.
bias in the direction of seating, that is, in the direction of closing. The second spring 75 urges the valve body 65 in a direction away from the valve seat 64, that is, in an opening direction. The spring force of the second spring 75 is smaller than the spring force of the first spring 73 when the first spring 73 is in an expanded state, that is, when the first spring 73 is not in contact with the liquefied natural gas. It is. When the first spring 73 comes into contact with liquefied natural gas and its strength decreases, the second spring 75 contracts against the spring force of the second spring 75, thereby separating the valve body 65 from the valve seat 64. In this way, the leaked liquefied natural gas will be discharged from the outlet 60.

In this relief valve 7, at normal temperature,
The valve body 65 is pressed against the valve seat 6 by the spring force of the first spring 73.
4, and the valve is closed. Therefore, the inlet 54 side is shut off from the atmosphere, and air does not flow into the pipes 5a, 5 upstream of the relief valve 7, the leakage detection valve 6, etc., and an explosive mixture or air leakage occurs. The operation of the leak detection valve 6 and the like will not become uncertain due to freezing of moisture inside or rainwater. In addition, when liquefied natural gas leaks, the first spring 73 of the relief valve 7 is directly cooled, its strength is reduced, and the valve body 65 is forced to the valve seat due to the force of the second spring. 64, and the leaked liquefied natural gas is immediately discharged from the pipe 5b to a safe place. As a result, the pipe lines 5, 5a, the leakage detection valve 6, etc. are not pressurized. In addition, the first
Since the spring 73 is in direct contact with the leaked liquefied natural gas, it operates satisfactorily even if the amount of leaked liquefied natural gas is small and vaporized.

In the above embodiment, compressed air was used as the working fluid and the air horn 8 was used as the alarm means, but in other embodiments of the present invention, other inert gases such as nitrogen, liquids, etc. may be used as the working fluid. May also be used as an air horn8
Instead, other alarm means that detects the pressure of the working fluid and issues an alarm may be used.

Effects As described above, according to the present invention, the leaked liquefied natural gas to be detected is deformed by contacting the spring made of the shape memory alloy through the partition member, and thereby the leakage detection valve is in the open state,
Since the working fluid is supplied from the working fluid source through this valve to activate the alarm means, leaked liquefied natural gas can be reliably detected at all times without mixing with the working fluid. In addition, the leaked liquefied natural gas to be detected in the relief valve is deformed by directly contacting the first spring made of a shape memory alloy, and the relief valve is opened and the leaked liquefied natural gas is moved to a safe place. This prevents leaked liquefied natural gas from pressurizing the inside of the device. The first spring of the relief valve is such that when there is no leakage of liquefied natural gas, the relief valve is in a closed state due to its spring force, so that atmospheric air can enter from here and create an explosive mixture. This device will not freeze due to dripping, atmospheric moisture, or rainwater.

With this, leaked liquefied natural gas can be detected reliably at all times, and countermeasures can be quickly taken when a leak occurs. Additionally, there is no risk of explosion due to leaked liquefied natural gas.

[Brief explanation of the drawing]

FIG. 1 is an overall system diagram of an embodiment of the present invention, FIG. 2 is a sectional view of the leak detection valve 6 used in the present invention, and FIG. 3 is an exploded perspective view of the partition member 12 and its vicinity.
FIG. 4 is a sectional view of another leak detection valve 6a used in the present invention, FIG. 5 is an exploded perspective view of the valve body 32 and its vicinity, and FIG. 6 is a sectional view of the relief valve 7 used in the present invention. 1...Liquefied natural gas transport pipe, 2...Cold insulation material, 4
... Cover, 5, 5a, 5b, 27 ... Pipe line,
6, 6a... Leak detection valve, 7... Relief valve, 8...
Air horn, 10, 30, 50...Valve box, 12,
35... Partition member, 18, 57... Valve seat member,
20, 64... Valve seat, 21... Air pressure source, 23,
32, 65... Valve body, 24... Guide tube, 25, 4
5... Spring, 66... Valve stem, 73... First spring,
75...Second spring.

Claims (1)

[Claims for Utility Model Registration] A leakage detection valve comprising a spring made of a shape memory alloy that deforms depending on the temperature of leaked liquefied natural gas, and a heat sensor that separates a spring chamber housing the spring from an inlet of the leaked natural gas. a partition member made of a conductive material, a working fluid source supplying a working fluid, an alarm means actuated by the working fluid, and interposed between the working fluid source and the alarm means, the partition member being interposed between the working fluid source and the alarm means, and being interposed between the working fluid source and the alarm means, A leakage natural gas relief valve comprising: a leakage detection valve having a valve means that is opened; and a leakage natural gas relief valve including a spring made of a shape memory alloy that deforms depending on the temperature of the leakage liquefied natural gas. Gas detection device.