JPH0210430Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a leakage detection device for detecting a leakage of a fluid to be detected, such as a gas.

Background technology For example, in LNG (liquefied natural gas) piping,
Gas leak detection was performed as follows. LNG piping is joined by flanges, for example, with bolts, and the entire piping, including the flange portion, is covered with a cold insulator. In such piping, a detection tube such as a vinyl tube is inserted into the above-mentioned flange through a cold insulating material, and gas leaking from the above-mentioned flange is guided to the outside of the cold insulating material. An inspector who periodically patrols the gas guided outside the cold insulation material connects the vinyl tube to a portable gas detector, for example, to detect the presence or absence of gas leakage.

Problems that the invention aims to solve: With such prior art, gas leaks can only be detected when an inspector goes around, and when rainwater enters the vinyl tube and freezes inside,
There was a problem that gas leakage could not be detected.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluid leak detection device that can solve the above-mentioned problems and quickly detect leaks of working fluid.

Means for Solving the Problems The present invention comprises: a working fluid source for pumping working fluid; a working conduit connected to the working fluid source; a fluid detection element connected to the working conduit; and a pressure sensing element connected to the working fluid source. It has a drive piece made of shape memory alloy, and its shape changes when the fluid to be detected comes into contact with it.
This is a fluid leakage detection device characterized by including an on-off valve that is brought into an open state by this, and a detection tube that guides the fluid to be detected to a drive piece.

Operation A working fluid source through which working fluid is pumped and a working conduit connected to this working fluid source are arranged. This operating conduit is provided with a fluid detection element and an on-off valve. This on-off valve has a drive piece made of a shape memory alloy, and changes its shape when it comes into contact with the fluid to be detected, thereby opening the valve.

When the fluid to be detected leaks, it is guided to the drive piece of the on-off valve via the detection pipe. This drive piece changes shape, thereby opening the on-off valve. At this time, the working fluid from the working fluid source flows past the on-off valve via the working conduit to actuate the pressure sensing element. In this way, leakage of the fluid to be detected can be quickly detected.

Embodiment FIG. 1 is a schematic diagram of a fluid leak detection device 1 according to an embodiment of the present invention. An air pipe 2 is provided as a working fluid source to which compressed air as a working fluid is fed under pressure. This air pipe 2 has a fluid to be detected, such as LNG (liquefied natural gas) flowing through it.
It is provided along the LNG pipe 3.

The parts of the air pipe 2 that correspond to the flanged parts F1, F2, ..., Fn of the LNG pipe 3 are connected through working conduits P1, P2, ..., Pn (collectively referred to as P), respectively. On-off valves V1, V2, . These on-off valves V1, V2,
..., Vn include whistles A1, A2, which are fluid detection elements,
..., An (collectively referred to as A) are connected. These whistles A are blown by the air flow from the on-off valve V.

A pressure reducing valve 4 and a throttle valve 5 are provided on the upstream side of the air pipe 2 in the compressed air flow direction to maintain the pressure within the air pipe 2 constant. Further, a pressure switch 6 for detecting negative pressure in the air pipe 2 is provided on the downstream side in the flow direction.
A cold insulating material K is provided to cover the LNG pipe 3, and a sealing member 10 such as putty and a cover body C made of metal are provided to cover the cold insulating material K. Flange part F of LNG piping 3 having such a configuration
1, F2, ..., Fn, detection tubes B1, which lead leaked gas to on-off valves V1, V2, ..., Vn by inserting a cold insulating material K and a cover body C, respectively, are inserted.
B2,...,Bn are provided.

FIG. 2 is a sectional view of the vicinity of the on-off valve V1 in FIG. 1. The flange portion F1 of the LNG pipe 3 is flange-coupled via a packing 7 with bolts 9 or the like. Further, a sealing material 10 such as putty is interposed between the cold insulating material K and the cover body C.

The on-off valve V1 includes a valve body 11 and a cover body 12 airtightly provided on the valve body 11. Valve body 11
A working fluid is introduced into the valve chamber 13 from the aforementioned air pipe 2 via the working conduit P1.

A valve seat 14 is located on the opposite side of the valve body 11 from the cover body 12 and near the connection part with the operating conduit P1.
is formed. Further, a whistle A1 is provided at the opposite end of the valve body 11. In addition, the valve seat 14
A valve body 15 is arranged at a position facing the valve body 15, and a valve stem 16 is fixed to this valve body 15. A spring receiver 17 is fixed to the end of the valve rod 16 on the opposite side from the valve body 15. A protrusion 18 is provided between the spring receiver 17 and the valve body 15 and protrudes radially outward of the valve rod 16 in the circumferential direction.

A detection tube B1 that opens near the joint F1 of the LNG pipe 3 is provided on the side of the cover body 12.
In addition, on the opposite side of the cover body 12 from the valve body 11,
A spring receiver 19 and an adjustment screw 20 are provided. A spring member 21 is provided between these spring receivers 17 and 19. The strength of the spring force of the spring member 21 can be adjusted using the adjustment screw 20. This spring member 21 is formed from a shape memory alloy. Further, a diaphragm 22 is provided between the cover body 12 and the valve body 11, the valve rod 16 is inserted into the vicinity of the center of the diaphragm 22, and the lower surface of the diaphragm 22 in FIG.
Supported by.

The above-described spring member 21 made of shape memory alloy spring-biases the valve stem 16 downward in FIG.
Cut off the working fluid from 1.

The operating state of the fluid leak detection device 1 having the above-described configuration will be described. Referring to Figure 2,
Assume that gas is leaking from near the joint F1 of the LNG pipe 3. The gas leaked at this time is guided to the on-off valve V1 via the detection pipe P1. Since the leaked gas guided to the on-off valve V1 is at a low temperature, the spring member 21 made of shape memory alloy is contracted, and the valve stem 16 is displaced in the direction of arrow Y2. Therefore, a gap is created between the valve body 15 and the valve seat 14, and the working fluid from the working conduit P1 flows into the valve chamber 13.
is given to the whistle A1 via the whistle A1, and this whistle A1 is blown.

Referring to FIG. 1, when the working fluid is released from the air pipe 2 through the on-off valve V1 and the whistle A1, the pressure inside the air pipe 2 decreases. The pressure switch 6 detects this decrease in pressure, and the detection of this negative pressure can be detected by a monitoring device (not shown) or the like. When a gas leak is detected in this way, the whistle A1 is blown at the relevant location as described above, so it is possible to easily confirm the occurrence of a leak related to the LNG pipe 3 and the location of the leak. .

FIG. 3 is a front view of a wind turbine 23 included in another embodiment of the present invention, and FIG. 4 is a side view of FIG. 3. In this embodiment, a windmill 23 is used in place of the whistle A of the previous embodiment. A bearing 2 fixed to one end of a support rod 25 fixed to a fixed base 24
6 is rotatably provided with a rotating shaft 27. For example, four blades 28a, 28b, 28c, 28 are provided at the end of the rotating shaft 27 opposite to the bearing 26.
d (collectively referenced 28) is fixed.
The rotary shaft 27 is also provided with a ratchet 29 for preventing reverse rotation. This windmill 23 is rotated when air released from the lower end 30 of the on-off valve V1 in FIG. 2 is applied as indicated by arrow D in FIG. 4. This shaft of rotation 27 also has the advantage that it does not rotate when there is no release of working fluid from the end 30 or when the working fluid flow provided to the windmill 23 is at a low velocity, whereas it rotates when this working fluid flow is at a high velocity. The brake is applied to create an appropriately selected frictional force so as to With such a wind turbine 23, it is possible to detect a leakage point in the LNG pipe 3 as explained in FIG. 1.

In the above-described embodiment, the driving piece is a spring member 21 made of a shape memory alloy, but instead of this spring member 21, for example, a bellows-shaped driving piece may be used.

Effects As described above, according to the present invention, the working conduit is connected to the working fluid source that pumps the working fluid. A fluid detection element and an on-off valve are connected to this operating conduit. This on-off valve has a drive piece made of a shape memory alloy, and changes its shape upon contact with the fluid to be detected, thereby opening the valve. By detecting the open state of this on-off valve, the location of fluid leakage can be detected. Further, when the valve is in an open state, a fluid detection element connected to the operating conduit detects this valve open state. In this way, it is possible to easily detect the occurrence of leakage of the fluid to be detected and the location of the leakage.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a fluid leak detection device 1 according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the vicinity of the on-off valve V1 in FIG. FIG. 4 is a front view of the wind turbine 23 shown in FIG. 3, and FIG. 4 is a side view of FIG. 1...Fluid leak detection device, 2...Air piping,
3...LNG piping, 6...pressure switch, 21...
...Spring member, B1...Detection tube, V1...Opening/closing valve.

Claims (1)

[Claims for Utility Model Registration] A working fluid source that pumps working fluid, a working conduit connected to the working fluid source, a fluid detection element connected to the working conduit, and a shape memory alloy connected to the fluid detection element. It has a driving piece that changes its shape when the fluid to be detected comes into contact with it.
A fluid leakage detection device comprising: an on-off valve that is brought into an open state; and a detection tube that guides the fluid to be detected to a drive piece.