JP2002031580A - Gas leak detection device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas leak detection device and a method capable of detecting surely only massive leak by discriminating temporary discharge of gas from the massive leak. SOLUTION: This device is equipped with an adjuster 50 for adjusting the pressure of gas supplied from the gas supply side to a low pressure, a pressure sensor 40 for sensing the gas pressure adjusted by the adjuster 50, and a gas cutoff valve 41 for cutting off the gas supplied from the adjuster 50 to the gas consumption side. In the device, the gas cutoff valve 41 is closed only when the state where the gas pressure sensed by the pressure sensor 40 is out of a normal range continues as long as a prescribed time or longer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas leak detecting device and method for detecting gas leak, and more particularly to a technique for reliably detecting only a large amount of gas leak.

[0002]

2. Description of the Related Art Conventionally, there has been known a gas supply system configured to detect leakage of liquefied propane gas (hereinafter, simply referred to as "gas") and prevent its release. Such a conventional gas supply system is, for example, shown in FIG.
As shown conceptually in FIG. 1, it comprises a high-pressure gas emission preventer 10, a primary regulator 20 and a secondary regulator 30.

[0003] The high-pressure gas supplied from the container is supplied to the primary regulator 20 via the high-pressure gas emission preventer 10. The primary regulator 20 adjusts the input high-pressure gas to a medium-pressure gas, and supplies the gas to the secondary regulator 30. The secondary regulator 30 adjusts the input medium-pressure gas to a low-pressure gas,
Supply to the combustion equipment on the gas consuming side.

In the gas supply system configured as described above, when a large amount of gas leaks in the high-pressure section upstream of the primary regulator 20, the high-pressure gas release preventing device 10 operates, and the primary regulator is removed from the container. Turn off the gas supply to 20.

Another conventional gas supply system, as conceptually shown in FIG. 8B, for example, comprises a medium-pressure gas emission preventer 11, a primary regulator 20, and a secondary regulator 30. I have. The high-pressure gas supplied from the container is supplied to the primary regulator 20. The primary regulator 20 adjusts the input high-pressure gas to a medium-pressure gas, and supplies the gas to the secondary regulator 30 via the medium-pressure gas emission preventer 11. The secondary regulator 30 adjusts the input medium-pressure gas to a low-pressure gas,
Supply to the combustion equipment on the gas consuming side.

In the gas supply system configured as described above, if a large amount of gas leaks at a medium pressure portion downstream of the primary regulator 20 and upstream of the secondary regulator 30, the gas for medium pressure is discharged. The protector 11 is activated and the primary regulator 2
From 0, the gas supply to the secondary regulator 30 is shut off.

[0007]

As described above, in the conventional gas supply system, the gas release preventing device is provided in the high-pressure section or the medium-pressure section. Therefore, when a large amount of gas leaks, for example, almost in an open state in the high-pressure section or the medium-pressure section, the gas release preventer operates reliably to prevent the release of gas. However, when a large amount of gas leaks in the low-pressure section downstream of the secondary regulator, there is a problem that the gas emission preventer may not function.

Further, since the conventional gas emission preventing device has high sensitivity, it may operate even when an instantaneous overflow condition occurs. In the normal use of a gas supply system, it is acceptable that momentary overflow conditions occur while the gas is being consumed in the combustion appliance. In such a case, when the gas emission preventer operates, there is a problem that normal gas supply cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for discriminating between temporary release of gas and large-volume leakage and reliably detecting only large-volume leakage. It is an object of the present invention to provide a leak detecting device and method.

[0010]

In order to achieve the above object, an invention according to claim 1 is provided with a regulator for adjusting the pressure of a gas supplied from a gas supply side to a low pressure, and the regulator comprises: A sensor for sensing the pressure of the adjusted gas, a gas shutoff valve for shutting off the gas supplied from the regulator to the gas consuming side, and a state in which the pressure of the gas sensed by the sensor is outside the normal range for a predetermined time. Control means for closing the gas cutoff valve only when the above is continued.

According to the first aspect of the present invention, the gas shutoff valve is determined to be a gas leak only when the state in which the pressure of the gas detected by the sensor is out of the normal range continues for a predetermined time or more. Is closed, but even if the sensor detects that the gas pressure is out of the normal range, if the state does not continue for a predetermined time or longer, it is not determined that there is a gas leak, and the gas shutoff valve is not closed. Therefore, only a large amount of gas leakage can be reliably detected.

According to a second aspect of the present invention, in the gas leak detecting device according to the first aspect, the control means determines that the state in which the pressure of the gas detected by the sensor is equal to or less than a threshold value smaller than a normal range is equal to or less than a predetermined time. The gas shutoff valve is closed only when the above operation is continued.

According to the second aspect of the present invention, when a large amount of gas is discharged, the low pressure of the gas falls below the normal range, so that the state in which the gas pressure is below the threshold lower than the normal range is equal to or longer than the predetermined time. Only when the continuation is continued, it is determined that there is a gas leak, and by closing the gas shut-off valve, only a large amount of gas leak can be reliably detected.

According to a third aspect of the present invention, the pressure of the gas supplied from the gas supply side is adjusted to a low pressure, the pressure of the adjusted gas is sensed, and the pressure of the sensed gas is reduced. The gas supplied to the gas consuming side is shut off only when the state outside the normal range continues for a predetermined time or more.

According to the third aspect of the invention, the same effect as that of the first aspect of the invention can be obtained.

Further, the invention according to claim 4 is the same as the invention according to claim 3.
In the gas leakage detection method described above, the gas shutoff valve is closed only when a state in which the pressure of the gas detected by the sensor is equal to or less than a threshold value smaller than a normal range continues for a predetermined time or more.

According to the fourth aspect of the invention, the same effect as that of the second aspect of the invention can be obtained.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a gas leak detection device according to an embodiment of the present invention. This gas leak detection device includes a regulator 50, a pressure sensor 40, a gas shutoff valve 41, and a microcomputer 42.

In this embodiment, a case where a single-stage depressurizing low-pressure regulator is used as the regulator 50 will be described. However, the regulator 50 used in the present invention is a single-stage depressurizing low-pressure regulator. However, the present invention is not limited thereto, and an automatic switching regulator and various other regulators can be used. The automatic switching regulator has a use side container and a spare side container, and when the gas is consumed by opening both the use side container and the spare side container, the pressure of the use side container becomes below a certain pressure. In this case, gas automatically flows from the container on the spare side to cover the consumption in both cases.

The regulator 50 reduces the pressure of the gas from the container (not shown) to a pressure most suitable for combustion, and suppresses the fluctuation of the pressure of the gas supplied to the combustion equipment (not shown) to achieve stable combustion. Used to keep going.

The inlet of the regulator 50 is connected to a container filled with a high-pressure gas, and the outlet is connected to a gas shut-off valve 41 via a pressure sensor 40. Hereinafter, the upstream side of the regulator 50 may be referred to as a high pressure side, and the downstream side may be referred to as a low pressure side.

FIG. 2 is a diagram showing the structure of a single-stage pressure reducing low-pressure regulator used as the regulator 50. As shown in FIG. The inlet of this regulator 50 is connected to the container side, and the outlet is connected to the combustion equipment side.

First, when the valve of the container (not shown) is opened, the high-pressure gas from the container passes through the nozzle 51 and passes through the decompression chamber 5.
Enter 2. At this time, if the outlet of the adjuster 50 is closed, the gas pressure in the decompression chamber 52 increases, overcoming the force of the pressure adjustment spring 54 that is pushing down the diaphragm 53, and the diaphragm 53 is pushed upward. As a result, the lever 55 connected to the diaphragm 53 performs a lever action, and the valve rod 56 moves to the left to close the nozzle 51 at the gas inlet. The pressure at 52 does not rise any further.

Next, when the gas is discharged from the outlet, that is, when the gas is consumed, the pressure in the decompression chamber 52 is reduced and the diaphragm 53 is also lowered. Accordingly, the valve 57 is opened, and the gas flows in from the inlet on the high pressure side. I do. Here, when the outlet is closed again, that is, when the consumption is stopped, the diaphragm 53 rises, the valve 57 is closed, and the flow of gas from the inlet stops.
The pressure in the decompression chamber 52 at this time is called a closing pressure.

As described above, since the regulator 50 has a structure in which the opening of the valve 57 is changed by the vertical movement of the diaphragm 53, when the outlet pressure tries to rise or fall depending on the level of the inlet pressure or the amount of outflow, The degree of opening of the valve 57 changes, and the outlet pressure is kept almost constant. This outlet pressure is called an adjustment pressure.

Further, if the regulator 50 breaks down and abnormal pressure is applied to the low pressure side, gas leakage, breakage of the rubber tube, etc. may occur, which may cause an accident. Are provided with safety devices.

When the pressure on the low pressure side of the regulator 50 becomes equal to or higher than the normal closing pressure corresponding to the inlet pressure, the valve 57 opens the nozzle 5.
1 and the lever 55 and the rod 58 interlocking with the valve rod 56 cannot move any further even if the pressure is going to rise. However, when the pressure exceeds a certain value, the diaphragm 53 overcomes the resultant force of the safety device pressure adjusting spring 59 and the pressure adjusting spring 54, and
8, and the safety valve seat 60 of the rod 58
A gap is formed between the diaphragm and the diaphragm 53. The gas is released from the gap through the vent 61 to the outside, and the rise of the outlet pressure is prevented.

When the regulator 50 configured as described above functions normally below the capacity point, the regulator 50 exhibits a low pressure characteristic with respect to the gas flow rate as shown in FIG. It fluctuates within the range between the upper pressure limit and the lower pressure limit.

When the adjuster 50 is used for a long time,
As shown in FIG. 4, the pressure may fluctuate up and down beyond the normal range several minutes after the start of consumption due to the gas reliquefaction phenomenon. In this case, even if the low pressure deviates from the normal range, it converges to the normal range in a very short time.

In FIG. 1, the pressure sensor 40 detects the pressure of the gas adjusted to a low pressure by the adjuster 50. The pressure value detected by the pressure sensor 40 is supplied to the microcomputer 42 as a sensor signal.

The gas shut-off valve 41 is provided in a low-pressure pipe from the regulator 50 to the combustion equipment. This gas shut-off valve 4
Numeral 1 responds to a shutoff signal sent from the microcomputer 42 to shut off the gas passage formed by the low-pressure pipe.

The microcomputer 42 detects the presence or absence of a large amount of gas leakage based on the sensor signal from the pressure sensor 40 and controls the opening and closing of the gas shutoff valve 41. This microcomputer 42 has a built-in counter 43.

FIGS. 6 and 7 show a case where a large amount of gas is consumed beyond the capacity point of the regulator 50 and a case where a large amount of gas is released due to breakage of the connection with the low-pressure pipe or the combustion equipment. 1 shows the behavior at low pressure.

When a large amount of gas is consumed beyond the capacity point of the regulator 50, the low pressure temporarily enters the abnormal range as shown on the left side of FIG. (A minute) The normal range is restored after elapse.

However, if a large amount of gas is released due to breakage of the connection with the low-pressure pipe or the combustion equipment, as shown in the right side of FIG. ) Generally does not return to the original normal range.

The gas leak detecting device according to this embodiment measures such a long time that the state in which the low pressure is in the abnormal range is continued for a long time (minute B).
If it does not return to the normal range even after elapse, it is determined that there is an abnormality, and the gas passage is shut off by the gas shut-off valve 41. Such an operation is realized by the processing of the microcomputer 42.

Next, the operation of the gas leak detecting device according to this embodiment configured as described above will be described with reference to the flowchart shown in FIG. 5 and the explanatory diagrams shown in FIGS. 6 and 7. The flowchart shown in FIG. 5 shows a processing procedure performed by the microcomputer 42.

First, the counter 43 built in the microcomputer 42 is cleared (step S10).
Next, the pressure value detected by the pressure sensor 40 is taken in (step S11). Then, it is checked whether or not the taken-in pressure value is within the normal range (step S1).
2). Then, when it is determined that it is within the normal range, the sequence returns to step S10.

Thereafter, steps S10 to S12 are repeatedly executed as long as the pressure value detected by the pressure sensor 40 maintains a normal range. In a normal state, the gas leak detection device monitors an abnormality of the gas pressure on the low pressure side by repeatedly executing steps S10 to S12.

If it is determined in step S12 that the pressure value detected by the pressure sensor 40 is not in the normal range during the repetition of steps S10 to S12, the sequence proceeds to step S13, where the counter 43 increments. Is done. Then, as a result of this increment, it is checked whether or not the count value in the counter 43 has exceeded a predetermined value (step S14). here,
The “predetermined value” is a value corresponding to B shown in FIG.

When it is determined that the count value does not exceed the predetermined value, the sequence returns to step S11, and thereafter, steps S11 to S14 are repeatedly executed until the count value in the counter 43 becomes the predetermined value or more. . That is, once the abnormality of the gas pressure is detected, step S1
The counter 43 measures the duration of the abnormal state by repeatedly executing 1 to S14.

If it is determined in step S14 that the count value has exceeded the predetermined value during the repetitive execution of steps S11 to S14, that is, if the abnormal state continues for B minutes, the sequence proceeds to step S15. The shutoff valve 41 is closed. Thereby, the function of closing the gas shut-off valve 41 is realized when the connection portion with the low-pressure pipe or the combustion appliance is broken and a large amount of gas is released.

On the other hand, if it is determined in step S12 that the pressure value from the pressure sensor 40 is in the normal range during the repeated execution of steps S11 to S14, that is, the continuation of the abnormal state is continued for A minutes (A <B). ), The sequence returns to step S10, and the contents of the counter 43 are cleared.

Thereafter, steps S10 to S12 are repeatedly executed as long as the pressure value detected by the pressure sensor 40 maintains the normal range. This realizes a function of not closing the gas cutoff valve 41 even when a large amount of gas is consumed beyond the capacity point of the regulator 50.

As described above, according to the gas leakage detection device of this embodiment, the state where the pressure of the gas detected by the pressure sensor 40 is out of the normal range is maintained for a predetermined time (B
Only when it has continued for more than (min), it is determined that a gas leak has occurred, and the gas shutoff valve 41 is closed. In this case, when a large amount of gas is released, the low-pressure pressure of the gas drops below the normal range. Only when it is determined that there is a gas leak, the gas shut-off valve is closed. However, even if the pressure sensor detects that the gas pressure is equal to or lower than the threshold value, the gas leak is not continued for a predetermined time (B minutes). Is not determined, and the gas shutoff valve 41 is not closed.

Therefore, even if a large amount of gas is consumed beyond the capacity point of the regulator 50, the gas shut-off valve 41 is not closed.
The gas shutoff valve 41 is closed only when a large amount of leakage occurs such that a large amount of gas is released due to breakage of a connection portion with the low-pressure pipe or the combustion appliance. That is, a temporary release of gas and large-volume leakage are distinguished, and the gas shut-off valve 41
Can be closed. Therefore, the problem of the conventional gas supply system is solved.

[0048]

According to the first aspect of the present invention, it is determined that there is a gas leak only when the pressure of the gas detected by the sensor is out of the normal range for a predetermined time or more, and the gas is shut off. Although the valve is closed, even if the sensor detects that the gas pressure is out of the normal range, if the state does not continue for a predetermined time or longer, it is not determined that there is a gas leak, and the gas shutoff valve is not closed. Therefore, only a large amount of gas leakage can be reliably detected.

According to the second aspect of the present invention, when a large amount of gas is discharged, the low pressure of the gas falls below the normal range, so that the state in which the gas pressure is lower than the threshold lower than the normal range is equal to or less than the predetermined time. Only when the continuation is continued, it is determined that there is a gas leak, and by closing the gas shut-off valve, only a large amount of gas leak can be reliably detected.

According to the third aspect of the present invention,
The same effects as those of the above-described invention can be obtained.
Also, according to the invention described in claim 4, the same effect as that of the invention described in claim 2 is exerted.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a gas leak detection device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a structure of a regulator illustrated in FIG. 1;

FIG. 3 is a view showing a low pressure characteristic with respect to a gas flow rate of the regulator shown in FIG. 1;

FIG. 4 is a diagram for explaining an example in which a momentary abnormality occurs in the adjuster shown in FIG. 1;

FIG. 5 is a flowchart showing an operation of the gas leakage detection device according to the embodiment of the present invention.

FIG. 6 is a diagram for explaining the operation of the gas leak detection device according to the embodiment of the present invention.

FIG. 7 is a diagram for explaining the operation of the gas leak detection device according to the embodiment of the present invention.

FIG. 8 is a diagram for explaining a conventional gas leak detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 High-pressure gas emission prevention device 11 Medium-pressure gas emission prevention device 20 Primary regulator 30 Secondary regulator 40 Pressure sensor 41 Gas shutoff valve 42 Microcomputer 43 Counter 50 Regulator

Claims (4)

[Claims] A regulator for adjusting the pressure of the gas supplied from the gas supply side to a low pressure; a sensor for sensing the pressure of the gas adjusted by the regulator; and a supply from the regulator to the gas consuming side. A gas shutoff valve that shuts off the gas to be shut off, and control means that closes the gas shutoff valve only when a state in which the pressure of the gas detected by the sensor is out of a normal range continues for a predetermined time or more. A gas leak detection device characterized by the above-mentioned. 2. The method according to claim 1, wherein the control unit closes the gas shutoff valve only when a state in which the pressure of the gas detected by the sensor is equal to or less than a threshold value smaller than a normal range continues for a predetermined time or more. The gas leak detection device according to claim 1. 3. The pressure of the gas supplied from the gas supply side is adjusted to a low pressure, the pressure of the adjusted gas is sensed, and the state where the sensed pressure of the gas is outside the normal range is maintained for a predetermined time. A gas leak detection method characterized by shutting off gas supplied to a gas consuming side only when the above is continued. 4. The gas shut-off valve according to claim 3, wherein the gas shut-off valve is closed only when a state in which the pressure of the gas detected by the sensor is lower than a threshold value smaller than a normal range continues for a predetermined time or more. Gas leak detection method.