JPH0348469Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an apparatus for detecting leakage of liquefied gas, such as liquefied natural gas, and for discharging the leaked liquefied gas.

BACKGROUND ART When liquefied natural gas leaks in a pipeline that transports liquefied natural gas, it is necessary to reliably guide the leaked liquefied natural gas to a safe location, such as a pit prepared in advance. It is possible to provide a cover that surrounds the cold insulation material covering the pipe line near the flange joint where liquefied natural gas is likely to leak, and connect the pipe line to this cover and pipe it to the pit. Conceivable. With such a configuration, there is a risk that the pipe line leading leaked liquefied natural gas to the pit, which is open to the atmosphere, may become blocked by freezing.

Problems to be solved by this invention The purpose of this invention is to detect the leakage of liquefied gas, and to transport the leaked liquefied gas to a safe place without freezing the inside of the pipe. An object of the present invention is to provide a leakage detection and discharge device for liquefied gas that can guide and discharge liquefied gas.

Means for solving the problem The present invention is based on the part 3 where leakage of liquefied gas is to be detected.
is airtightly surrounded by a cover 4, and the liquefied gas leaking from the cover 4 is transferred to a pipe 5,
5a to leak detection valves 6, 6a and relief valve 7, respectively;
8; 30, 18; and the first valve body 10, 18; is housed in the first valve body 10, 18; 30, 18 and is made of metal having thermal conductivity, and
The valve body 10, 18; one end abuts against the spring receiver 14, 40 inside the valve body 10, 18; is made of a shape memory alloy, and is resistant to cooling below a specific temperature by liquefied gas. a spring 2 that contracts and expands at a temperature equal to or higher than the specific temperature;
5, 45, and a first valve body 23, 32 provided at the other end of the spring 25, 45, and the first valve body 10, 18;
Inlet 22, first outlet 26, and these first inlets 2
A first valve seat 20 is formed between the pipe line 5 and the first outlet 26 and faces the first outlet 26. 26, and when the first springs 25, 45 contract, the first valve body 23, 32 is separated from the first valve seat 20, and the first spring 2
The first valve bodies 23 and 32 are seated from the first valve seat 20 by the extension of the valves 5 and 45, the first inlet 22 is connected to a supply source 21 for supplying pressure fluid, and the first outlet 26 is connected to a supply source 21 for supplying pressure fluid. , means 8 actuated by the liquid from its first outlet 26 to detect the occurrence of a leak.
are connected, and the relief valve 7 includes: a second valve body 50, 53 having a second inlet 54 connected to the pipe line 5a and a second outlet 60 for discharging liquefied gas; 53, a second valve seat 64 formed between the second inlet 54 and the second outlet 60 and facing the second outlet 60; a second valve body 65 seated on the second valve seat 64; It is located on the second inlet 54 side of the second valve body 50, 53 than the second valve body 65, and is made of a shape memory alloy and expands at a certain temperature or higher due to the liquefied gas.
a first spring 73 that urges the second valve element 65 in a direction in which the second valve body 65 is seated on the second valve seat 64 and contracts below the specific temperature; gives a spring force to , and this spring force is
The second spring 75 has a spring force that is smaller than the spring force when the first spring 73 is expanded, and has a value that separates the second valve body 65 from the second valve seat 64 when the first spring 73 contracts. This is a liquefied gas leak detection and discharge device.

Effect According to the present invention, the part 3 where leakage of liquefied gas is to be detected is hermetically surrounded by the cover 4,
Therefore, freezing in the pipes 5, 5a is prevented, and leakage detection valves 6, 6a are prevented from freezing and malfunctioning, and leaked liquefied gas is prevented from forming in the pipes 5, 5a.
5a, the inside of the pipes 5, 5a is not frozen and blocked by moisture in the outside air,
The leakage detection valves 6 and 6a and the relief valve 7 are respectively guided. When the leaked liquefied gas reaches the leakage detection valves 6, 6a, the springs 25, 45 made of shape memory alloy are cooled and contracted through the spring receivers 14, 40, so that the first valve bodies 23, 32 1st valve seat 2
0, and a pressure fluid such as compressed air from a pressure fluid supply source 21 is supplied from a first inlet 22 to a first outlet 2.
via 6 to means 8 for detecting the occurrence of a leak, such as an air horn and a pressure detector;
This makes it possible to reliably detect leakage of liquefied gas.

Further, according to the present invention, the leaked liquefied gas is guided to the relief valve 7, and only when this liquefied gas reaches the relief valve 7 is the liquefied gas released to the first spring 73.
The second valve body 65 is separated from the second valve seat 64 by the spring force of the second spring 75. Before the leaked liquefied gas reaches the relief valve 7,
Since the second valve body 65 is seated on the second valve seat 64 and is in a closed state, the atmosphere does not freely enter the pipes 5, 5a, and therefore the liquefied gas does not enter the pipes 5, 5a. When flowing through the pipes 5a, moisture in the atmosphere is prevented from forming in the pipes 5, 5a.

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 a pipe 1 for transporting liquefied natural gas. This pipe 1 is connected by a flange joint 3. Cold insulation material 2 is installed near the flange joint 3 where there is a risk of leakage of liquefied natural gas.
It is surrounded by a cover 4 made of a material such as metal and hermetically sealed. The liquefied natural gas leaking from the vicinity of the flange joint 3 flows out from inside the cover 4 into the pipe line 5 connected to the cover 4. The pipe line 5 includes a valve 6 for detecting leakage, and a pipe line 5
A, a relief valve 7 which is an on-off valve, and a pipe line 5b through which the liquefied natural gas from the relief valve 7 flows out to a pit etc. are provided in this order. By the action of the leakage detection valve 6, compressed air is supplied to the air horn 8, which is an operating means, through the pipe line 27 and blows, thereby detecting the occurrence of a leakage.

FIG. 2 is a sectional view of the leak detection valve 6. 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 the valve body 10
It is screwed into the internal thread 16 formed in the. In this way, the partition member 12 airtightly partitions the conduit 5 side and 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 when cooled by liquefied natural gas, its strength decreases and it contracts below a certain temperature. When the temperature reaches a certain temperature or higher, the spring 25 expands again to the memorized shape. When the spring 25 is cooled by liquefied natural gas and contracts at a specific temperature, the compressed air displaces the valve body 23 to the right in FIG. 2, and the valve seat 20 and the valve body 23 are separated from each other.
Compressed air is thereby discharged from the outlet 26 of the valve body 10. Compressed air from outlet 26 is routed to line 2
7 to the air horn 8, and the air horn 8 blows. When the spring 25 is at a temperature higher than a certain temperature and is therefore stretched, the spring 25
The valve body 23 is resiliently seated on the valve seat 20 by the spring force. Therefore, the compressed air flows through the valve hole 1.
9 to the outlet 26.

First flange joint 3 for transporting liquefied natural gas
When a leak occurs in the vicinity, liquefied natural gas from inside the cover 4 is transferred from the pipe 5 to the leak detection valve 6.
into the recess 15 in the partition member 12. As a result, the spring receiving portion 1 of the partition member 12
4 is cooled. Therefore, the spring 25 made of a shape memory alloy is cooled and contracts, and the valve body 23 moves toward the valve seat 20.
distance from. 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.

FIG. 4 shows a leakage detection valve 6 according to another embodiment of the present invention.
FIG. In this embodiment, parts corresponding to those in the previous embodiment are given the same reference numerals.
A guide tube 33 in the shape of a right cylinder with a bottom and connected to the valve body 32 is inserted into the guide hole 31 of the valve box 30 .

FIG. 5 is an exploded perspective view of the valve body 32 and its vicinity. There is an internal thread 34 on the flange 11 side of the valve box 30.
is engraved, and an external threaded portion 36 of the partition member 35 is screwed into this internal thread 34. Partition member 3
5 is made of metal, which is a thermally conductive material, and the cylindrical portion 37 that penetrates into the pipe line 5 is made thin. The guide tube 33 is inserted into the guide hole 38 of the partition member 35 so as to be displaceable in its axial direction. An external threaded portion 39 is formed so as to be continuous with the cylindrical portion 37 and extend toward the conduit 5 side. An internal thread 41 of the spring receiving part 40 is screwed into this external threaded part 39 . A threaded portion 43 connected to the rod-shaped projection 42 is inserted into the spring receiving portion 40 .
A nut 44 is screwed into the threaded portion 43, thereby fixing the protrusion 42 to the spring receiving portion 40. The protrusion 42 enters into the guide hole 38 of the partition member 35. A gland seal 78 surrounding the guide cylinder 33 is attached by a seal presser member 79.

The coil spring 45 surrounds the protrusion 42 , one end of which can abut against the bottom 46 of the guide tube 33 , and the other end of which can abut against the spring receiver 40 . The spring 45 is made of a shape memory alloy, and when cooled by liquefied natural gas, its strength decreases and contracts below a certain temperature, and is in an expanded state at higher temperatures. 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 3
2 is away from the valve seat 20, the compressed air from the inlet 22 is discharged to the outlet 26, and is guided to the air horn 8 through the pipe 27 (see Figure 1), causing the air horn 8 to blow. be done.

When liquefied natural gas leaks from the flange joint 3 of the pipeline 1, the leaked liquefied natural gas is guided from the pipeline 5 to the leak detection valve 6a. As a result, the cylindrical portion 37 and the spring receiving portion 40 of the partition member 35 are cooled, and the spring 45 contracts accordingly. As a result, the valve body 32 and the guide cylinder 33 are
Displacement to the right in FIG. 4 is permitted. Compressed air from the inlet 22 is thus directed via the outlet 26 to the air horn 8 as described above.

When there is no liquefied natural gas leak,
The valve body 32 is resiliently seated on the valve seat 20 by the spring force of the spring 45, so that the compressed air from the inlet 22 is not guided from the outlet 26 to the air horn 8. In each of the above embodiments, the valve box 1
0 and the valve seat member 18 constitute a valve body (Fig. 2),
The valve body 30 and the valve seat member 18 also constitute a valve body (FIG. 4).

FIG. 6 is a longitudinal sectional view of the relief valve 7. Bento box 5
The flange 51 of 0 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 into which liquefied natural gas flows from the pipe line 5a is formed in the valve box 50, and a central hole 55 communicates with the inlet 54. An internal thread 56 is formed at the lower end of the central hole 55 in FIG. An outer thread 58 of a valve seat member 57 is screwed into this inner thread 56 . 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
The outlet 60 is connected to the outlet 60 formed in the joint member 53 . The valve seat member 57 has a mounting portion 61 in which an external thread 58 is carved, and a valve seat portion 62 that is connected to the mounting portion 61 and located within the valve chamber 59 . Valve seat part 6
2 is formed with a valve seat 64 provided with a seal member 63. The valve body 65 has a flat disk shape, and can be screwed onto 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). An external thread 69 is cut into the end of the valve stem 66 . A bottom 71 of a bottomed cylindrical spring receiving member 70 is inserted into the end of the valve stem 66, and the bottom 71 is fixed to the valve stem 66 by a nut 72 that is screwed into the threaded portion 69. .

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 . A communication hole 74 is formed in the support portion 67 to communicate the center hole 55 with the valve seat 64 side.

The first spring 73 is made of a shape memory alloy as described above, is cooled by liquefied natural gas, and contracts as the temperature decreases below 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. This second
The spring force of the spring 75 is smaller than the spring force of the first spring 73 when the first spring 73 is not in contact with liquefied natural gas. This second spring 75
When the spring 73 comes into contact with the liquefied natural gas, its strength decreases and it contracts against the spring force of the second spring 75, thereby separating the valve body 65 from the valve seat 64. The liquefied natural gas thus leaked 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 cut off from the atmosphere. Therefore, moisture in the air is prevented from forming on the inlet 54 side, that is, on the inlet 54, the pipes 5a and 5 above it, and the leakage detection valve 6. This ensures reliable operation of the leakage detection valve 6.

Although compressed air was used as the working fluid and the air horn 8 was used as the operating member in the above embodiment, other gases, liquids, etc. may be used as the working fluid in other embodiments of the present invention. Alternatively, instead of the air horn 8, a pressure detector or other actuating means may be used.

Effects As described above, according to the present invention, the cover 4 airtightly surrounds the portion 3 where leakage of liquefied gas is to be detected;
The spring receiving parts 14 and 40 of the leakage detection valves 6 and 6a partition the pipe line 5 and the first inlet 22 and the first outlet 26, and the relief valve 7 is connected to a second spring provided in the relief valve 7. Since the valve remains closed when no liquefied gas contacts 73, freezing in the pipes 5 and 5a is prevented, and the leak detection valves 6 and 6a can operate reliably.
Furthermore, while the leaked liquefied gas is flowing into the pipes 5, 5a, there is no fear that moisture in the atmosphere will freeze inside the pipes 5, 5a and block the pipes 5, 5a. do not have.

Accordingly, in the present invention, the leakage detection valves 6, 6a
can be used to reliably detect leaks of liquefied gas. Further, leaked liquefied gas can be reliably guided to a safe place through the relief valve 7 and discharged.

[Brief explanation of the drawing]

Fig. 1 is an overall system diagram of one embodiment of the present invention, Fig. 2 is a sectional view of the leak detection valve 6, Fig. 3 is an exploded perspective view of the partition member 12 and its vicinity, and Fig. 4 is another embodiment. A sectional view of an example leakage detection valve 6a, FIG. 5 shows the valve body 3
2 and its vicinity, and FIG. 6 is a sectional view of the relief valve 7. 1...Pipe, 2...Cold insulation material, 4...Cover, 5,
5a, 5b, 27...pipeline, 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, 21... Air pressure source, 23, 65... Valve body, 24... Guide cylinder, 2
5, 45... Spring, 64... Valve seat, 66... Valve stem, 73... First spring, 75... Second spring.

Claims (1)

[Scope of claim for utility model registration] Covering part 3 where leakage of liquefied gas should be detected 4
The liquefied gas leaking from the cover 4 is surrounded airtight by the pipe 5,
5a to leak detection valves 6, 6a and relief valve 7, respectively;
8; 30, 18; and the first valve body 10, 18; is housed in the first valve body 10, 18; 30, 18 and is made of metal having thermal conductivity, and
The valve body 10, 18; one end abuts against the spring receiver 14, 40 inside the valve body 10, 18; is made of a shape memory alloy, and is resistant to cooling below a specific temperature by liquefied gas. a spring 2 that contracts and expands at a temperature equal to or higher than the specific temperature;
5, 45, and a first valve body 23, 32 provided at the other end of the spring 25, 45, and the first valve body 10, 18;
Inlet 22, first outlet 26, and these first inlets 2
A first valve seat 20 is formed between the pipe line 5 and the first outlet 26 and faces the first outlet 26. 26, and when the first springs 25, 45 contract, the first valve body 23, 32 is separated from the first valve seat 20, and the first spring 2
The first valve bodies 23 and 32 are seated from the first valve seat 20 by the extension of the valves 5 and 45, the first inlet 22 is connected to a supply source 21 for supplying pressure fluid, and the first outlet 26 is connected to a supply source 21 for supplying pressure fluid. , means 8 actuated by fluid from its first outlet 26 to detect the occurrence of a leak.
are connected, and the relief valve 7 includes: a second valve body 50, 53 having a second inlet 54 connected to the pipe line 5a and a second outlet 60 for discharging liquefied gas; 53, a second valve seat 64 formed between the second inlet 54 and the second outlet 60 and facing the second outlet 60; a second valve body 65 seated on the second valve seat 64; It is located on the second inlet 54 side of the second valve body 50, 53 than the second valve body 65, and is made of a shape memory alloy and expands at a certain temperature or higher due to the liquefied gas.
a first spring 73 that urges the second valve element 65 in a direction in which the second valve body 65 is seated on the second valve seat 64 and contracts below the specific temperature; gives a spring force to , and this spring force is
The second spring 75 has a spring force that is smaller than the spring force when the first spring 73 is expanded, and has a value that separates the second valve body 65 from the second valve seat 64 when the first spring 73 contracts. Liquefied gas leak detection and discharge equipment.