JPH049952B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a fluid temperature detection operated valve that detects fluid temperature and opens a compressed air circuit.

<Prior Art> Conventionally, thermocouple thermometers are often used for temperature detection. If something is to be activated based on the temperature detection, for example to activate an alarm, an electric circuit is used. However, when the fluid is explosive fuel gas, the use of electric circuits is dangerous and cannot be easily used. In reality, manual inspections are performed as a safety measure against gas leaks at flange connections of liquefied natural gas (hereinafter referred to as LNG) transport pipes. In other words, installation of electric circuits is dangerous and must be done manually. As shown in Fig. 3, the gas leak inspection means measures the temperature near the outside of the flange connection part 3 of the LNG transport pipe 2 using a thermocouple thermometer 1 equipped with explosion-proof measures to determine whether there is a gas leak. Temperature measurements are used to determine this, because when LNG leaks, the temperature drops due to adiabatic expansion, so if that low temperature is detected, it can be determined that there is a gas leak. In the figure, 4 is a thermocouple, 5 is a heat insulating material, 6 is a scattering prevention cover, and 7 is a vinyl tube inserted into the vicinity of the flange joint surface through a hole provided in the scattering prevention cover. At the time of inspection, a thermocouple 4 is inserted into the vinyl tube 7 to measure the temperature.

<Problems to be solved by the invention> In the gas leak inspection of the LNG transport pipes mentioned above, the inspector carries a detector and inspects the detection points, so the monitoring is not continuous in time and is incomplete. be. Continuous inspection equipment using explosion-proof electrical circuits could be considered to complete this process, but it would be extremely expensive and would not guarantee 100% safety.

This invention can detect abnormal temperature and operate.
It is an object of the present invention to provide a fluid temperature sensing actuated valve capable of transmitting a clear signal by using compressed air without the risk of explosion.

<Means for Solving the Problems> The means of the present invention comprises: a valve hole formed between an inlet and an outlet of compressed air; a valve body provided to open and close the valve hole; A partition member having an insertion portion that partitions a fluid to be measured side and allows the valve body to move forward and backward; a closing spring that presses the pair of valves provided on the fluid to be measured side in a valve closing direction; a spring holder that abuts on one side and has a window for bringing the fluid to be measured into contact with the valve-closing spring;
A bellows is provided between the valve body and the partition member so as to isolate between the measured fluid side and the compressed air side, and when the valve closing spring reaches a predetermined temperature, it applies a valve closing force. The bellows is made of a shape memory alloy so as to disappear, and the bellows is attached in a stretched state so as to generate a valve opening force that is smaller than the valve closing force of the valve closing spring.

<Operation> The valve according to the above means is used by providing the spring holder of the valve closing spring to be located within the fluid to be measured, connecting the inlet with a compressed air supply path, and connecting the outlet with a signal transmission pipe. For example, when the fluid to be measured is leaking gas from a part of LNG that is predicted to leak, a shape-memory alloy closure valve whose spring action is preset to disappear at a predetermined low temperature will be used to prevent gas leakage. The spring is directly cooled, and the valve-closing force that was previously generated disappears. As a result, a valve-opening force appears and the valve opens. The valve opening force is due to the air pressure on the inlet side and the force that tends to contract the bellows.
The valve-closing force of the valve-closing spring does not disappear instantaneously, but gradually disappears because the spring constant gradually decreases as the temperature decreases. For this reason, if a bellows that does not generate a reaction force to contract is used, the valve will open only by the air pressure on the inlet side, and although the valve will open, the valve will open due to the opening. The state of action of the compressed air on the inlet side that is acting on the body changes instantaneously, and the valve-opening force of the compressed air decreases, and the action force of the valve-closing spring, whose spring constant has not decreased sufficiently, prevails. When the valve is closed, the valve is opened again by compressed air on the inlet side, and this state is repeated until the spring constant decreases enough to open the valve completely. That is, while the valve changes from a closed state to a completely open state, the valve body temporarily vibrates in opening and closing, causing an unstable state of compressed air coming out of the outlet. Therefore, the signal during this period is unclear. Since this invention uses something that generates a valve-opening force that tends to contract the bellows, it is possible to prevent the above-mentioned signal from becoming unclear. That is, once the valve body is opened, the bellows acts to maintain the valve open state and suppresses vibration of the valve body. Since the inlet and the outlet communicate with each other by opening the valve body, compressed air is supplied to the signal transmission pipe and sent to a desired position as a gas leak detection signal. Since the bellows can completely isolate the fluid to be measured from the compressed air side, mixing of both fluids can be prevented.

<Example> One example is shown in FIG. In the figure, 10 is a main body, 11 is a valve hole, 12 is a valve body, 13 is a valve closing spring, 14 is a spring receiver, and 15 is a bellows.

The main body 10 includes an inlet 20 formed in the compressed air supply pipe joint, an outlet 21 formed in the signal transmission pipe joint, a valve hole 11 provided in a passage communicating therebetween, a valve seat 23, and a valve. It has a chamber 24, an insertion portion 25 for a valve stem 26 (described later), and a mounting flange 22 provided on the extension side of the valve stem 26 so as to surround this. The insertion portion 25 is connected to a partition member 38 as shown in the figure.
The partition member 38 is provided so as to airtightly partition the inside of the valve chamber 24 from the fluid to be measured at the upper side of the figure.

The valve body 12 is a plate valve located in the valve chamber 24 and provided to open and close the valve hole 11.
Compressed air pressure acts as a valve-opening force from the side, and the valve stem 26 extends rearward in the opening/closing direction of the valve body 12 and passes through the insertion portion 25. A stepped spring receiver 27 with a small diameter is formed, and the small diameter portion 28 is attached to the mounting flange 2.
The end protrudes from the bonding surface of the two.

The valve closing spring 13 is made of a shape memory alloy, surrounds the outside of the small diameter portion 28 of the valve stem 26, and has one end attached to the valve stem 2.
The other end contacts the spring receiver 27 of No. 6, and the other end contacts the spring receiver 14, and is provided in a compressed state to perform a valve closing action.
The valve closing spring 13 is set in advance so that it deforms and loses its spring action when it reaches a predetermined low temperature.

The spring receiver 14 includes an end surface that contacts the valve-closing spring 13 and a cylindrical portion surrounding the valve-closing spring 13 and the small diameter portion 28, and is coupled to the main body 10 side. A window 29 is provided in the cylindrical portion to communicate inside and outside.

The bellows 15 is made of a low-temperature resistant metal (SUS304 or copper-based material) and connects the valve stem 26 to the valve chamber 2.
4, one end of which is surrounded by the insertion portion 2.
The other end is welded to the opening edge on the valve chamber 24 side of valve body 1.
2, and is in a tensioned state so as to generate a valve-closing force when the valve body 12 is seated on the valve seat 23 in the closed state. The valve opening force is sufficiently smaller than the valve closing force of the valve closing spring 13. This perose 15 extends the sliding gap between the valve stem 26 and its insertion portion 25 into the valve chamber 24.
Since the fluid to be measured comes into contact with the valve closing spring 13 through the window 29, the fluid to be measured does not mix into the valve chamber 24 side.

This fluid temperature detection operating valve 30 is used as shown in FIG. In this figure, on the outside of the flange connection part 3 of the LNG transport pipe 2 similar to that shown in Fig. 3,
A leakage capture box 32 is provided to form a space 31 , and a flange 33 that matches the mounting flange 22 of the fluid temperature detection operating valve 30 and a sensor entry hole 34 are provided in the box 32 .
A compressed air supply pipe 35 connected to the inlet 20, a signal transmission pipe 36 connected to the outlet 21, and an air horn 37 connected to the pipe 36 are separately provided. This is an LNG leak detection device.
In the figure, 5 is a heat insulating material, and 6 is a scattering prevention cover.

This device, when LNG leaks into the box 32,
The temperature of that part decreases, and the fluid inside the box 32 directly contacts the valve closing spring 13 and cools it, so the spring force of the valve closing spring 13 disappears due to the decrease in temperature, and the valve body 12 The valve is opened by the valve opening force due to the contraction of the bellows 15 and the compressed air pressure acting on the valve body 12. The valve opening operation is performed by the valve opening spring 13
In the process where the spring constant of decreases as the temperature decreases,
Once the valve is opened, the valve opening state is maintained due to the valve opening force of the bellows 15, and the valve body 12 is completely opened without vibration. When the valve body 12 opens, stable compressed air without fluctuation is reliably supplied from the compressed air supply pipe 35 to the air horn 37 via the signal transmission pipe 36. This activates the air horn 37 to issue an alarm. In this case, the compressed air supplied to the signal transmission pipe 36 not only transmits signals but also operates the air horn 37. Therefore, operating a device such as an air horn requires more compressed air than simply transmitting a signal, but this fluid temperature detection operating valve 30 does not pose a problem as long as the opening degree of the valve is increased to a certain extent. . In this regard, it is possible to use a diaphragm instead of the bellows 15, but the diaphragm does not necessarily provide a sufficient valve opening.

<Effects of the Invention> The valve according to the present invention detects the temperature of the fluid, for example, abnormal temperature, and transmits the detection signal using compressed air without the danger of explosion.
It can be used more completely than devices that include electrical circuits in LNG leak detection devices and detection devices for dangerous temperatures on the high-temperature side of explosive gases.

By providing the bellows, it is possible to reliably isolate the constant fluid side and the compressed air side, making it possible to provide the valve closing spring in direct contact with the fluid to be measured. Therefore, the response to temperature changes in the fluid being measured is fast.
Abnormalities can be detected early.

Furthermore, by providing the bellows with a valve-opening force, vibrations of the valve body at the initial stage of valve opening can be suppressed, without the need for a special valve-opening spring, and vibrations can be generated from the outlet side at the early stage of valve opening. The air signal can be made stable and reliable.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is a partial sectional view showing an example of use of the embodiment, and FIG. 3 is a sectional view for explaining a conventional LNG leakage inspection means. 10...Main body, 11...Valve hole, 12...Valve body,
13... Valve closing spring, 14... Spring holder, 15... Bellows, 29... Window, 38... Partition member.

Claims (1)

[Claims] 1. A valve hole formed between the inlet and outlet of compressed air, a valve body provided to open and close the valve hole, and an insertion hole that partitions the compressed air side and the measured fluid side and moves the valve body forward and backward. a partition member having a section, a valve-closing spring provided on the side of the fluid to be measured that presses the valve body in the valve-closing direction, and a valve-closing spring for abutting one of the valve-closing springs and bringing the fluid to be measured into contact with the valve-closing spring; a spring receiver provided with a window, and a bellows provided between the valve body and the partition member so as to isolate between the fluid to be measured side and the compressed air side,
The valve-closing spring is formed of a shape memory alloy such that the valve-closing force disappears when the valve-closing spring reaches a predetermined temperature, and the bellows generates a valve-opening force that is smaller than the valve-closing force by the valve-closing spring. A fluid temperature sensing actuated valve mounted in an extended position to