JP3045214B2 - Airtight leak sensor in gas piping - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airtight leak sensor used for a gas airtight leak inspection in a gas pipe periodically performed in a gas pipe installation.

[0002]

2. Description of the Related Art Conventionally, techniques in such a field include:
For example, Japanese Patent Application Laid-Open No.
There was one described in 5-27847. That is, the above-mentioned airtight leak sensor in the gas pipe is a valve rod slidably provided opposite to a valve seat nozzle provided at a gas inlet of a pressure regulator interposed in a gas pipe system. A conductive rubber that changes the electrical resistance value by pressing force is provided at the back of the rubber packing provided on the end surface of the gasket, and by detecting the change in the electrical resistance value of the conductive rubber, the presence or absence of airtight leakage in the gas pipe is determined. Was detected.

[0003]

However, in such an airtight leak sensor made of conductive rubber in a gas pipe,
There have been problems such as fluctuations in electrical resistance due to aging of the conductive rubber, periodic replacement of the conductive rubber to prevent errors due to aging, and an increase in maintenance costs for this periodic replacement.

The present invention solves such problems of the prior art, and does not require periodic replacement of the conductive rubber, which is an airtight leak sensor due to aging, eliminates maintenance costs, and improves durability and reliability. It is an object to provide an airtight leak sensor in a gas pipe that can be improved.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a valve seat nozzle provided at a gas inlet of a pressure regulator interposed in a gas piping system. A semiconductor pressure detecting device that changes the resistance value of the resistance bridge circuit by warping due to pressing by the valve rod, at least in the back of the rubber packing provided on the end face of the slidably provided valve rod,
An open chamber which allows warping of the semiconductor pressure detecting device, and a liquid for giving a substantially uniform pressing from the valve rod to the semiconductor pressure detecting device are provided, and a voltage is obtained from a change in the resistance value of the resistance bridge circuit of the semiconductor pressure detecting device. An airtight leak sensor in a gas pipe is configured to detect the presence or absence of an airtight leak in a gas pipe by detecting a change.

[0006]

According to the present invention, when gas is used and the gas flows normally in the pipe, the semiconductor pressure detecting device does not receive pressure from the valve rod, and thus the resistance value of the bridge circuit of the semiconductor pressure detecting device. Does not change, and no voltage is generated because the respective resistance values are in an equilibrium state. When no gas is used and the gas does not flow through the pipe, the semiconductor pressure detecting device receives pressure from the valve rod, and the resistance value of the bridge circuit of the semiconductor pressure detecting device changes, and the semiconductor pressure detecting device is in an unbalanced state. Generates voltage.

Further, even when the gas is not used, when the gas leaks in the piping system, the pressure from the valve rod to the semiconductor pressure detecting device is lower than when there is no gas leak. Drops. Therefore, it can be understood that there is a gas leak in the gas piping system if the unbalanced voltage is any while the gas is not used.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of an airtight leak sensor in a gas pipe according to the present invention. FIG.
FIG. 2 is a cross-sectional view of a pressure regulator provided with an airtight leak sensor of the present invention, FIG. 2 is a main part showing the first embodiment of FIG. 1, and FIG. The main part showing the embodiment of
Further, FIG. 4 shows an embodiment of the method for inspecting gas pipes for airtight leakage according to the present invention.

In this embodiment, a valve rod 22 is provided on an end face 60 of a valve rod 22 slidably opposed to a valve seat nozzle 10d provided at a gas inlet of a pressure regulator interposed in a gas piping system. At least in the back of the rubber packing 23, a semiconductor pressure sensor 28 that changes the resistance value of the resistance bridge circuit by warpage due to gas pressure, an open chamber 35 that allows warping of the semiconductor pressure sensor 28, and a semiconductor Oil 34 is provided to apply a substantially uniform pressure to the pressure sensor 28, and the presence or absence of airtight leakage in the gas pipe is detected by detecting a voltage change from a change in the resistance value of the resistance bridge circuit of the semiconductor pressure sensor 28. ing.

This pressure regulator has a case body 10,
The case body 10 is provided with a protruding hollow cylindrical portion 10a. The hollow cylindrical portion 10a is connected to the connecting portion 10 projecting outward.
b, and the connection portion 10b has a gas inflow hole passing through the center.
10c is provided. This gas inlet 10c also has
A nozzle 10d for a valve seat protruding around the inner end is provided. The case main body 10 is provided with a connection pipe 10e at a position facing the hollow cylindrical portion 10a. A flange 10f is formed on the upper edge of the case body 10. On the outer periphery of the connection portion 10b, a hollow connection screw is rotatably fitted.
11 are provided. A seal ring 12 is fitted on the distal end surface of the connection portion 10b.

The opening of the case body 10 has a case lid 13.
The case lid 13 is provided with a flange 13a at a position facing the flange 10f. At the top of the case lid 13, a hollow cylindrical portion 13b is provided.
An internal thread 13c is formed on the inner peripheral surface of 13b. A diagram 14 is provided between the case body 10 and the case lid 13, and the outer peripheral edge of the diagram 14 has flanges 10f and 13f.
is pinched by a. Diagram 14 also includes
A disk-shaped backing plate 15 is formed.

Further, a rod 16 is provided through the center of the diagram 14 and the center of the backing plate 15, and the rod 16 is provided with a fastening nut 17 and a washer 18 for fastening. Inside the hollow cylindrical portion 13b of the case lid 13, a stepped disk-shaped ring for spring pressing 19 is screwed. A small-diameter coil spring 20 and a large-diameter coil spring 21 are interposed concentrically between the spring holding ring 19 and the backing plate 15.

A valve rod 22 is slidably provided in the hollow cylindrical portion 10a of the case body 10 so as to face the valve seat nozzle 10d, and an end face 60 of the valve rod 22 has a rubber packing.
23 is fitted. A vertically split groove 22a is provided at the inner end of the valve rod 22, and a bent portion of a substantially U-shaped lever 24 is inserted into the groove 22a and pivotally supported by a pin 25.

The lever 24 has an outer end 24a, which is pivotally supported on the case body 10 by a pin 26. The lever 24 also has an inner end 24b,
The inner end 24b passes through a groove 16a provided at the lower end of the rod 16, and its lower edge is supported by a support pin 27 provided at the lower end of the groove 16a. A groove 10g (dotted line in FIG. 1) for gas flow is provided on the inner peripheral surface of the hollow cylindrical portion 10a.

In FIG. 2, a rubber packing 23 provided on an end face 60 of a valve rod 22 slidably provided opposite to a valve seat nozzle 10d provided at a gas inlet of the pressure regulator 2 is provided. , A semiconductor pressure sensor 28 is provided. This sensor
28 is a sensor in which, for example, a bridge circuit is formed on a semiconductor surface by a resistor formed by diffusing impurities, and when pressure is applied to the semiconductor, warpage occurs, and the resistor is distorted. is there. The sensor 28 is provided with a power supply terminal plate 29.
A conductor 30 is soldered to 29, for example. A DC power supply 31 such as a battery is connected to the conductor 30. The sensor 28 is also provided with a signal terminal plate 36, and a conductor 37 is soldered to the terminal plate 36, for example. An instrument 32 for detecting a voltage change from the sensor 28 is connected to the conductor 37. Further, between the sensor 28 and the rubber packing 23, there is provided a semiconductor pressure sensor movement open chamber 35 that allows the sensor 28 to be warped due to pressing on the sensor 28. Between the valve rod 22 and the sensor 28, on the sensor 28 side, a pressure sensor pressing oil 34 such as silicone oil for evenly pressing the sensor 28 is provided, and on the valve rod 22 side, Diaphragm
33 are provided.

In FIG. 3, a rubber packing 23 provided on an end face 60 of a valve rod 22 slidably provided opposite to a valve seat nozzle 10d provided at a gas inlet of the pressure regulator 2 is provided. , A semiconductor pressure sensor 50 is provided. This sensor
Reference numeral 50 denotes a sensor in which, for example, a resistor formed by diffusing impurities is formed on the surface of a semiconductor, and when a pressure is applied to the semiconductor, a warp is generated, so that the resistor is distorted, and the resistance changes due to the distortion. The sensor 50 is provided with a terminal plate 51, and a conductor 52 is soldered to the terminal plate 51, for example. The conductor 52 is connected to a power supply 53 and a meter 54 connected in series. In addition, sensors
Between the rubber packing 23 and the rubber packing 23, there is provided an open chamber 57 for exercising the semiconductor pressure sensor, which allows the warpage of the sensor 50 caused by the pressing on the sensor 50 . Valve rod 22 and sensor
Between the sensor 50 and the sensor 50, a pressure sensor pressing oil 56 such as silicone oil is provided on the sensor 50 side for evenly pressing the sensor 50, and a diaphragm 55 is provided on the valve rod 22 side. ing. The power supply 53 is a sensor
DC power supply such as a battery that supplies power to 50, meter
54 is an instrument for detecting the resistance value of the sensor 50.

The open chambers 35 and 57 may be integral with the sensors 28 and 50 or may be separate. The open chambers 35 and 57 only need to allow the sensors 28 and 50 to warp. A protective cover may be provided between the sensors 28 and 50 so that the oils 34 and 56 pressing the sensors 28 and 50 do not directly touch the oil.

FIG. 4 shows an embodiment of the method for inspecting gas pipes for airtight leakage according to the present invention. In the figure, a gas cylinder 1 for supplying gas is connected to a pressure regulator 2 having a function of detecting the presence or absence of airtight leakage in a gas pipe, and the pressure regulator 2 further controls the gas usage via a pipe 5. It is connected to a microcomputer gas meter 3 for measuring. The gas meter 3 is connected to a gas stove 4 via a pipe 5 and an on-off valve (main valve) 6. Connected in this way,
The gas piping system has been inspected for leaks.

When the pressure regulator constructed as described above is connected to the gas piping system, the gas that has entered the gas inlet hole 10c of the inlet-side connection portion 10b retreats the valve rod 22 due to the pressure. The gas enters the decompression chamber A in the case body 10 through the groove 10g and is decompressed, and flows out from the connection pipe portion 10e on the outlet side.

The decompression in the decompression chamber A is determined by a force generated by the inflowing gas pressure acting on the diaphragm 14 to push up the diaphragm 14 and a repulsive force between the coil springs 20 and 21. Therefore, the reduced pressure can be adjusted by adjusting the repulsive force of the coil springs 20, 21.

As described above, when the inflowing gas flows out from the outlet of the pressure regulator, the pressure in the decompression chamber A is reduced. 16 is depressed, and as a result, the lever 24 is caused to move as shown by the arrow B in FIG.
The valve rod 22 is slid in the direction of arrow C via the pin 25. If the valve rod 22 moves in the direction of arrow C, the valve rod
The rubber packing 23 provided on the end face 60 of the nozzle 22 is a valve seat nozzle 10d.
Let the gas flow away from it.

When the on-off valve (the main stopper 6 in FIG. 4) is closed in the piping system, outflow of gas stops, and as a result, the pressure in the decompression chamber A rises, so that the diaphragm 14 is pushed up and the end of the lever 24 Push up the part 24b, so that the valve rod
22 is pushed outward and the rubber packing 23 is
Press d to stop the gas flow. FIGS. 1, 2 and 3 show this closed state.

When the gas is used, the valve between the valve seat nozzle 10d and the end face of the valve rod 22 is opened, and when the gas is stopped, the valve is closed. In the case of FIG. 2, since the sensor 28 does not receive pressure when the valve is open, the resistance value of the bridge circuit does not change. Therefore, when the valve is closed, the sensor 28 is pressed. Changes and detects an unbalanced voltage, for example, several tens of millivolts. Therefore, by detecting the magnitude of the unbalanced voltage from the change in the resistance value of the bridge circuit of the sensor 28, it is possible to detect the gas usage state and the gas non-use state. Further, even when the gas is not used, if there is a gas leak in the piping system, the gas pressure in the decompression chamber A becomes lower than in the case where there is no gas leak, so that the unbalanced voltage is reduced accordingly. Therefore, even when the gas is not used, if the unbalance voltage is reduced to some extent, it is known that there is a gas leak in the gas piping system.

In the case of FIG. 3, when the valve is opened, the sensor 50 does not receive pressure, so that the resistance value is a predetermined resistance value.
When the valve is opened, the sensor 50 is pressed, so that the resistance value is smaller than a predetermined resistance value. When the sensor 50 is pressed, the resistance value may be larger than a predetermined resistance value that does not receive the pressure. Therefore, by detecting the magnitude of the resistance value of the sensor 50, it is possible to detect the gas use state and the gas non-use state. Further, even when the gas is not used, if there is a gas leak in the piping system, the gas pressure in the decompression chamber A becomes lower than in the case where there is no gas leak, so that the resistance value becomes smaller or larger. Therefore, even when the gas is not used, if the resistance value is slightly reduced or increased, it is known that there is a gas leak in the gas piping system.

[0025]

As described above in detail, according to the airtight leak sensor in the gas pipe of the present invention, the semiconductor pressure sensor is used as the airtight leak sensor in the pressure regulator provided in the pipe. There is virtually no change due to aging,
Therefore, an excellent effect of eliminating the need for sensor replacement, reducing maintenance costs, and improving durability and reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a pressure regulator provided with a semiconductor pressure sensor of the present invention.

FIG. 2 is an enlarged view showing a first embodiment of a main part of FIG. 1 according to the present invention;

FIG. 3 is an enlarged view showing a second embodiment of the main part of FIG. 1 according to the present invention;

FIG. 4 is an explanatory view showing an embodiment of a method for inspecting airtightness of a gas piping system according to the present invention.

[Explanation of symbols]

1 Gas cylinder 2 Pressure regulator 3 Microcomputer gas meter 4 Gas stove 5 Piping 6 On-off valve (main valve) 10 Case body 10d Valve seat nozzle 11 Connection screw 12 Seal ring 13 Case lid 14, 33, 55 Diaphragm 15 Patch plate 16 Rod 17 Fastening nut 18 Washer 19 Spring holding ring 20 Small diameter coil spring 21 Large diameter coil spring 22 Valve rod 23 Rubber packing 24 Lever 25, 26 pin 27 Bearing pin 28, 50 Semiconductor pressure sensor 29 Power supply terminal plate 30, 37 , 52 Conductor 34, 56 Oil for pressing semiconductor pressure sensor 35, 57 Open chamber for semiconductor pressure sensor movement 36 Signal terminal plate 51 Terminal plate 60 End face of valve rod

Claims (3)

(57) [Claims] 1. A rubber packing provided on an end surface of a valve rod slidably provided opposite to a valve seat nozzle provided at a gas inlet of a pressure regulator interposed in a gas piping system. At least, a semiconductor pressure detecting device that changes a resistance value of a resistance bridge circuit by warpage due to pressing by the valve rod; an open chamber that allows warping of the semiconductor pressure detecting device; A liquid for giving uniform pressure, and detecting the presence or absence of airtight leakage in the gas pipe by detecting a voltage change from a change in the resistance value of the resistance bridge circuit of the semiconductor pressure detection device. Airtight leak sensor in gas piping. 2. A rubber packing provided on an end face of a valve rod slidably provided opposite to a valve seat nozzle provided at a gas inlet of a pressure regulator interposed in a gas piping system. At least, a semiconductor pressure detecting device that changes a resistance value by warping by pressing by the valve rod; an open chamber that allows warping of the semiconductor pressure detecting device; and a substantially uniform pressing from the valve rod to the semiconductor pressure detecting device. An airtight leak sensor in the gas pipe, wherein the sensor detects the presence or absence of airtight leak in the gas pipe by detecting a change in the resistance value of the semiconductor pressure detecting device. 3. An airtight leak sensor according to claim 1, wherein said liquid is silicone oil.