JP2023001971A - Valve leakage detection device and method - Google Patents

Abstract

To provide a valve leakage detection device which can easily detect leakage gas from a ground part of a valve without requiring the power.SOLUTION: A valve leakage detection device 1 for detecting leakage of fluid from a ground part 54 of a valve 50 comprises: a leakage flow path 10 which guides the leaking fluid from the ground part 54; a pilot-type switching valve 20 which is connected to the leakage flow path 10; a pilot flow path 30 which branches from the leakage flow path 10 and guides the pilot pressure to the pilot-type switching valve 20; and a discharge flow path 40 which is connected to the leakage flow path 10 via the pilot-type switching valve 20. The pilot-type switching valve 20 makes the leakage flow path 10 communicate to the discharge flow path 40 when the pilot pressure becomes equal to or greater than the set pressure, but shuts off the leakage flow path 10 from the discharge flow path 40 when the pilot pressure becomes less than the set pressure.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a valve leakage detection device and method, and more particularly to a valve leakage detection device and method for detecting leakage from a gland portion of a valve.

Conventionally, in order to detect gas leaking from the gland portion of the valve, a drilled hole is formed in the valve and the leaked gas discharged into the atmosphere from the drilled hole is checked by a detector or the like. However, this leak detection method is difficult to adopt in the case of a leaking gas (for example, hydrogen) for which exposure to the atmosphere may pose a problem.

As a method for detecting a ground leak from a gland portion, Patent Document 1 discloses that a solenoid valve and a pressure transmitter are provided in a leak offline where leaked fluid is guided from the gland portion of a valve in the reactor containment vessel, and the solenoid valve is closed. It is described that an alarm is output when the pressure value exceeds the set value while the pressure is on. After the leakage is detected, the electromagnetic valve is opened by operating the electromagnetic valve operation switch, and the leaked fluid is guided to the LCW sump for treatment, thereby preventing the leaked fluid from being released to the atmosphere.

JP-A-2-136795

The leak detection method of Patent Document 1 mentioned above is capable of leak detection independent of the fluid temperature by outputting an alarm when the pressure rises in the leak offline. Since it is necessary to close the solenoid valve again after the pressure is released, there is a problem that the operation of such a solenoid valve operation switch becomes complicated. In addition, since electric power is required to operate the solenoid valve, there is a possibility that the installation location will be restricted.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a valve leakage detection apparatus and method capable of easily detecting leakage gas from a gland portion of a valve without requiring electric power.

The object of the present invention is to provide a device for detecting fluid leakage from a gland portion of a valve, comprising: a leak passage for guiding the leaked fluid from the gland portion; and a pilot type switching valve connected to the leak passage. a pilot flow path that branches from the leak flow path and guides pilot pressure to the pilot type switching valve; and a discharge flow path that is connected to the leak flow path via the pilot type switching valve, wherein the pilot The switching valve communicates the leak passage with the discharge passage when the pilot pressure is equal to or higher than a set pressure, and disconnects the leak passage from the discharge passage when the pilot pressure is less than the set pressure. This is achieved by a valve leak detection device that

It is preferable that the valve leakage detection device further includes a pressure detection unit that detects the pilot pressure.

A throttle valve is preferably provided in the pilot flow path.

A check valve is preferably provided in the discharge channel.

Further, the object of the present invention is a valve leakage detection method using the valve leakage detection device described above, wherein the valve includes an inner tube through which a cryogenic fluid passes and an outer tube covering the inner tube. is connected to a vacuum double pipe in which a vacuum layer is formed in the valve, and the discharge channel is connected to the vacuum layer to detect leakage of the cryogenic fluid passing through the inner pipe. be done. The cryogenic fluid can be exemplified by liquefied hydrogen.

According to the present invention, it is possible to provide a valve leakage detection apparatus and method capable of easily detecting leakage gas from a gland portion of a valve without requiring electric power.

1 is a schematic configuration diagram of a valve leakage detection device according to an embodiment of the present invention; FIG.

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of a valve leakage detection device according to an embodiment of the present invention. A valve leakage detection device (hereinafter simply referred to as a "leakage detection device") 1 shown in FIG.

The vacuum double pipe 100 includes an inner pipe 101 and an outer pipe 102 made of a metal material such as stainless steel. Fluid passes in the direction of arrow F.

The outer tube 102 is arranged concentrically with the inner tube 101 so as to cover the inner tube 101 , and a vacuum layer 103 is formed between the inner tube 101 and the outer tube 102 . The vacuum layer 103 is evacuated by a vacuum pump (not shown) to vacuum-insulate the inner tube 101 .

The valve 50 includes a valve body 51, a valve body 52 arranged in the valve body 51, and a valve shaft 53 that rotatably supports the valve body 52. As shown in FIG. The upstream and downstream sides of the valve body 51 are air-tightly flanged to the upstream and downstream portions of the inner tube 101 with fasteners such as bolts and nuts. The flow path of the inner tube 101 can be opened and closed by rotating it.

The leak detection device 1 of the present embodiment includes a leak passage 10 for guiding the leaked fluid from the gland portion 54 of the valve 50, a pilot switching valve 20 connected to the leak passage 10, and a leak from the leak passage 10. It has a pilot flow path 30 branched to guide the pilot pressure to the pilot type switching valve 20 and a discharge flow path 40 connected to the leak flow path 10 via the pilot type switching valve 20 . The leak channel 10, the pilot channel 30, and the discharge channel 40 are configured by, for example, piping.

The pilot-type switching valve 20 is a three-port pilot valve that operates when pilot air is supplied to the pressure-receiving chamber. While the leak passage 10 is cut off from the discharge passage 40 by the biasing force of the spring 21, when the pilot pressure is equal to or higher than the set pressure, the valve body moves against the biasing force of the spring 21, and the leak passage 10 is closed. is communicated with the discharge channel 40 .

An orifice 31 is provided in the pilot flow path 30 , and the orifice effect of the orifice 31 suppresses a rapid drop in pilot pressure when the leak flow path 10 communicates with the discharge flow path 40 . A pressure gauge 32 is provided between the orifice 31 and the pilot type switching valve 20 in the pilot flow path 30 as a pressure detector for detecting pilot pressure.

The discharge channel 40 is connected to the vacuum layer 103 by connecting the distal end to the connecting hole 102 a of the outer tube 102 . A branch channel 41 is connected to the discharge channel 40 , and at the tip of the branch channel 41 , the leaked fluid guided to the discharge channel 40 can be collected by other collecting equipment or the like. Branching of the leaked fluid by the branch flow path 41 can be performed by operating the on-off valves 42 and 43 . A check valve 44 is provided in the discharge channel 40 to prevent the leakage fluid from flowing back from the discharge channel 40 to the leak channel 10 .

Next, the operation of the leak detection device 1 having the above configuration will be described. When the cryogenic fluid passing through the inner pipe 101 of the double vacuum pipe 100 leaks from the gland portion 54 of the valve 50 and the leaked fluid is led to the leak channel 10, the leak channel 10 is blocked from the discharge channel 40. Therefore, the pilot pressure acting on the pressure receiving chamber of the pilot type switching valve 20 increases. Since this pilot pressure is detected by the pressure gauge 32, the presence or absence of ground leak can be determined from this detected value.

When the pilot pressure reaches or exceeds the set pressure of the pilot type switching valve 20 , the leak passage 10 is communicated with the discharge passage 40 to guide the leaked fluid to the discharge passage 40 . As a result, the pressurized leaking fluid in the leak passage 10 is released, the pilot pressure drops below the set pressure of the pilot type switching valve 20, and the leak passage 10 is cut off from the discharge passage 40 again. . The orifice 31 provided in the pilot flow path 30 moderates the decrease in pilot pressure, so that it is possible to prevent repeated switching operations of the pilot type switching valve 20 due to changes in the pilot pressure. 10 can be reliably cut off from the discharge channel 40 . The set pressure of the pilot type switching valve 20 can be appropriately adjusted based on the detected value of the pressure gauge 32 .

As described above, the leakage detection device 1 of the present embodiment can easily and accurately detect the state of leakage from the pressure of the leaked fluid guided to the leak flow path 10, and after detecting the leakage, The pilot type switching valve 20 is automatically restored, and leakage detection becomes possible again without requiring electric power.

The leak detection method using the leak detection device 1 can be applied not only to the valve 50 connected to the vacuum double pipe 100, but also to the detection of ground leaks in various valves such as air conditioners, steam turbines, and power plants. However, when applied to the valve 50 of the vacuum double pipe 100 as in the present embodiment, by connecting the discharge flow path 40 to the vacuum layer 30, the atmosphere of the leaked fluid can be removed without requiring new equipment. Opening can be easily suppressed. This is particularly effective when the cryogenic fluid flowing through the inner tube 101 is a fluid, such as liquid hydrogen, for which exposure to the atmosphere may pose a problem.

The discharge channel 40 of the present embodiment is provided with a branch channel 41 to enable selective collection by the vacuum layer 30 or other collection equipment. may be configured. When the discharge channel 40 is connected only to the vacuum layer 30, the tip side of the discharge channel 40 is always maintained at a negative pressure, so that the backflow of the leaked fluid is reliably prevented without providing the check valve 44. be able to. Depending on the type of leaked fluid that is led to the discharge channel 40, it can be released to the atmosphere without being collected.

Leak detection by the leak detection device 1 can also be performed based on detection of the switching operation of the pilot type switching valve 20 instead of detection by the pressure gauge 32 . The switching operation of the pilot switching valve 20 can be detected by, for example, providing a magnetic sensor or the like to the pilot switching valve 20 to directly detect the switching operation of the valve, or by detecting changes in the temperature, pressure, etc. of the discharge passage 40. You can also do it by

1 Valve Leak Detection Device 10 Leak Flow Path 20 Pilot Switching Valve 30 Pilot Flow Path 31 Throttle Valve 32 Pressure Gauge (Pressure Detector)
40 discharge channel 44 check valve 50 valve 54 gland portion 100 vacuum double pipe 101 inner pipe 102 outer pipe 103 vacuum layer

Claims (6)

A device for detecting fluid leakage from a valve gland,
a leak channel that guides the leaked fluid from the gland;
a piloted switching valve connected to the leak flow path;
a pilot flow path that branches from the leak flow path and guides pilot pressure to the pilot type switching valve;
a discharge channel connected to the leak channel via the pilot switching valve,
The pilot switching valve communicates the leak passage with the discharge passage when the pilot pressure is equal to or higher than a set pressure, and connects the leak passage with the discharge passage when the pilot pressure is less than the set pressure. A leak detection device for valves that shut off from 2. The valve leakage detection device according to claim 1, further comprising a pressure detection unit that detects the pilot pressure. 3. A valve leakage detection device according to claim 1, wherein a throttle valve is provided in said pilot passage. 4. The valve leakage detection device according to claim 1, wherein a check valve is provided in said discharge passage. A valve leakage detection method using the valve leakage detection device according to any one of claims 1 to 4,
The valve is connected to a vacuum double pipe in which a vacuum layer is formed between an inner tube through which the cryogenic fluid passes and an outer tube that covers the inner tube,
A leak detection method for a valve, wherein the discharge channel is connected to the vacuum layer to detect leakage of cryogenic fluid passing through the inner tube. 6. The valve leakage detection method according to claim 5, wherein the cryogenic fluid is liquefied hydrogen.

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