JPH07198526A - Abnormality detection device for gas supply system - Google Patents

Abstract

PURPOSE:To detect automatically and early such abnormality as gas leakage at a gas supply system in the upper stream of a gas meter. CONSTITUTION:A gas meter 20 is provided with a speaker 24 which emits sound wave toward upper stream side and a microphone 25 which detects the reflection wave, emitted by the speaker 24 and reflected in the gas supply system. A control part 30 compares the pattern data of reflection wave detected by the microphone 25 when the gas supply system is normal with that of at inspection, and, based an the comparison result, abnormality in the gas supply system is identified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas supply system abnormality detecting device for detecting an abnormality such as a gas leak in a gas supply system.

[0002]

2. Description of the Related Art Generally, a domestic gas meter has a function of measuring the flow rate of passing gas, and also detects the gas supply pressure with a pressure switch (pressure sensor) to detect the pressure when the gas is not used. When a drop is detected, or when a gas flow rate above a predetermined amount is detected using a flow meter,
When the gas flow rate is detected for a predetermined period or longer, the gas cutoff valve is driven to cut off the gas flow path.
In this way, leaks in pipes, outflows of unnatural gas, etc. are detected to prevent accidents and ensure safety.

FIG. 7 shows a schematic configuration of a conventional gas supply system for general households. The gas meter 1 is arranged in the vicinity of the house 2, and gas is supplied to the gas inlet of the gas meter 1 through a main branch pipe 3 and a lamp inner pipe 4 which are buried underground. The outlet of the gas meter 1 is connected to each gas appliance inside the house 2 through an inner pipe 5 inside the lamp. Inside the house 2, a gas leak alarm 6 for issuing a gas leak alarm is arranged.

In this conventional gas supply system, the gas leak between the gas meter 1 and the gas plug 7 provided for each gas appliance in the house 2 is detected by the gas leak detection mechanism of the gas meter 1. When the gas meter 1 detects a gas leak, the gas is shut off. If there is a gas leak in the room, the gas leak alarm 6 can detect the gas and shut off the gas, or issue an alarm.

[0005]

As described above, in the conventional system, the gas leak on the downstream side of the gas meter 1 could be automatically detected by the gas meter 1. The gas meter 1 could not detect a gas leak in the buried gas pipe (inner pipe 4 outside the light) on the premises. Therefore, gas leaks have been detected by methods such as a patroller confirming by odor during a regular security patrol once every three years, a meter reader by odor during meter reading, and a consumer by odor.

[0006] However, in the case of an outdoor gas leak, since the gas diffuses, the conventional method cannot be found when the gas leak is very small, and there is a problem that it takes time to find the gas leak. It was In addition, since the regular inspection is performed only once every three years under the present circumstances, there is a problem that even if a gas leak occurs, it may be used for a long period of time without being detected and may lead to an accident.

The present invention has been made in view of the above problems, and an object thereof is to be able to detect an abnormality such as a gas leak in a gas supply system upstream of a gas meter, automatically and early. To provide an abnormality detection device for the gas supply system.

[0008]

According to a first aspect of the present invention, there is provided a gas supply system abnormality detecting device, wherein a pressure fluctuation generating means for generating a pressure fluctuation in a gas passage through which gas passes in the gas supply system, and the pressure fluctuation. Pressure fluctuation detection means for detecting pressure fluctuations due to reflected waves generated by the pressure fluctuation wave generated by the generation means reflected in the gas supply system, and pressure fluctuation detection means when the gas supply system is normal The pressure fluctuation data detected by the pressure fluctuation detection means at the time of inspection and the pressure fluctuation data stored by the storage means are compared, and the comparison result indicates the gas supply system An abnormality determining means for determining an abnormality is provided.

In this abnormality detecting device of the gas supply system, pressure fluctuation is generated in the gas flow path by the pressure fluctuation generating means, and the pressure fluctuation is caused by the reflected wave generated by the wave caused by the pressure fluctuation being reflected in the gas supply system. Is detected by the pressure fluctuation detecting means. The data of the pressure fluctuation detected by the pressure fluctuation detection means when the gas supply system is normal is stored by the storage means. Then, the abnormality determination means compares the pressure variation data detected by the pressure variation detection means during the inspection with the pressure variation data stored by the storage means, and determines the abnormality of the gas supply system based on the comparison result. .

According to a second aspect of the present invention, there is provided a gas supply system abnormality detecting apparatus, wherein the pressure variation generating means and the pressure variation detecting means in the gas supply system abnormality detecting apparatus of the first aspect of the present invention detect a gas passing through a gas flow path. It is provided in the gas meter that measures the flow rate.

[0011]

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

FIG. 1 is an explanatory diagram showing a gas supply system including a gas supply system abnormality detecting device according to an embodiment of the present invention. In this gas supply system, a gas a supplied through a main pipe or a branch pipe (hereinafter referred to as a main branch pipe) 10 buried in the ground, and a lamp inner pipe 11 in which a part is also buried in the ground
Sent to the gas meter 20 through this gas meter 2
After measuring the flow rate at 0, the gas is supplied to a gas appliance (not shown) in each home through the lamp inner tube 12.

The gas meter 20 has a safety function using a microcomputer. Inside the gas meter 20, a gas inlet 21 and a gas outlet 2 are provided.
The gas pipe 23 having the number 2 and forming a part of the gas flow path in the gas supply system is provided. In the gas pipe 23, a speaker 24 as a pressure fluctuation generating means for generating a pressure fluctuation in the gas flow path in order from the gas inlet 21 side.
And a microphone 25 as a pressure fluctuation detecting means for detecting a pressure fluctuation caused by a pressure fluctuation generated by the speaker 24, that is, a pressure fluctuation caused by a reflected wave generated when a sound wave is reflected in the gas supply system, and the gas pipe 23 is cut off. A gas cutoff valve 26 for controlling the gas flow rate and a gas flow meter 27 for measuring the flow rate of the gas passing through the gas pipe 23 are sequentially arranged.

A control unit 30 is provided in the gas meter 20 for inputting the output signals of the microphone 25 and the gas flow meter 27 and controlling the speaker 24 and the gas cutoff valve 26.

FIG. 2 shows a control unit 30 in the gas meter 20.
FIG. 3 is a block diagram showing a configuration around and. The control unit 30 includes a CPU (central processing unit) 31, a ROM (read only memory) 32, a RAM (random access memory) 33, a clock 34 for measuring time, and an input / output port 35. Are connected to each other by a bus 36. In addition to the gas flow meter 27 and the microphone 25 described above, the input / output port 35 includes the speaker 2
4, a drive circuit 37 for driving the gas shutoff valve 26, a drive circuit 38 for driving the gas cutoff valve 26, and a drive circuit 40 for driving an alarm lamp 39 provided in the gas meter 20 are connected. In the control unit 30, the CPU 31 controls the RA
By using the M33 as a working area and executing the program stored in the ROM 32, the gas meter 2
The function of detecting an abnormality such as a gas leak in the gas supply system (supply pipe 11) on the upstream side of 0 is realized.

FIG. 3 is a functional block diagram showing the function of the abnormality detecting device for the gas supply system of this embodiment. As shown in this figure, the abnormality detecting device of the gas supply system includes a pressure fluctuation generating means 41 for generating a pressure fluctuation in the gas flow path, and a wave caused by the pressure fluctuation generated by the pressure fluctuation generating means 41 for supplying the gas. A pressure fluctuation detecting means 42 for detecting a pressure fluctuation due to a reflected wave generated by being reflected in the system, and a first pressure storing means for storing the data of the pressure fluctuation detected by the pressure fluctuation detecting means 42 when the gas supply system is normal. Storage means 43
A second storage means 44 for storing the data of the pressure fluctuation detected by the pressure fluctuation detecting means 42 at the time of inspection, the data of the pressure fluctuation stored by the first storage means 43 and the second storage means 44. An abnormality determining unit 45 that compares the stored pressure fluctuation data and determines an abnormality of the gas supply system based on the comparison result, and the abnormality determining unit 4
5, an alarm means 46 is provided for issuing an alarm when the abnormality of the gas supply system is determined.

The pressure fluctuation generating means 41 is realized by the speaker 24, and the pressure fluctuation detecting means 42 is realized by the microphone 25. Further, the first storage means 43 and the second storage means 44 are realized by the RAM 33, the abnormality determination means 45 is realized by the control unit 30,
The alarm means 46 is realized by the alarm lamp 39.

Next, the operation of the abnormality detecting device for the gas supply system according to this embodiment will be described with reference to the flow chart shown in FIG.

In the abnormality detecting device for the gas supply system, first, when the gas supply system is normal, such as when the gas meter 20 or the pipe is newly installed, the pressure fluctuation generating means 41 generates a pulse-like pressure fluctuation (pulse sound). Then, a sound wave due to this pressure fluctuation is emitted toward the lamp inner tube 11 (step S1).
01). This sound wave is reflected at the connecting portion between the lamp inner tube 11 and the main branch tube 10 and returns to the gas meter 20 side. The pressure fluctuation due to this reflected wave is detected by the pressure fluctuation detecting means 42 (step S102). Then, the data of the pressure fluctuation pattern in the normal state detected by the pressure fluctuation detection means 42 is stored in the first storage means 43 (step S103). FIG. 5 shows an example of a pressure fluctuation pattern in this normal state.

Next, at the time of inspection performed at a predetermined cycle, the pressure fluctuation generating means 41 generates a pulse-shaped pressure fluctuation (pulse sound), and a sound wave due to this pressure fluctuation is generated.
The pressure fluctuation detection means 42 detects the pressure fluctuation due to the reflected wave generated by the sound wave being reflected toward the gas supply system (Step S104) (Step S104) (Step S104).
105). Then, the data of the pressure fluctuation pattern detected by the pressure fluctuation detecting means 42 is stored in the second storage means 44 (step S106).

FIG. 6 shows an example of a pressure fluctuation pattern due to a reflected wave when the gas supply system is abnormal. In the example shown in this figure, a fluctuation (hereinafter, referred to as a transient phenomenon) 51 that does not appear in the normal state appears before the reflected wave reflected at the connection portion between the lamp inner tube 11 and the main branch tube 10. This transient phenomenon 51 is due to corrosion leakage of the lamp inner tube 11. Also, when the gas component changes, the sound velocity changes, so the pressure fluctuation pattern moves in the time axis direction relative to the normal time. Therefore, by comparing the pressure fluctuation pattern at the time of inspection with the pressure fluctuation pattern at the normal time, it is possible to determine abnormality in the gas supply system such as corrosion leakage, water supply, and changes in gas components.

In this embodiment, the abnormality determining means 45
A matching calculation is performed between the pressure fluctuation pattern at the time of inspection stored by the second storage means 44 and the normal pressure fluctuation pattern stored by the first storage means 43, and the degree of matching between both patterns is obtained ( Step S107). The matching operation is, for example, to obtain the difference in sound pressure between the two patterns at each time, and to obtain the sum of absolute values of the difference or the sum of squared values of the difference. Note that the smaller the sum of the absolute values of such differences or the sum of the squared values of the differences, the greater the degree of matching between the two patterns. Abnormality discrimination means 45
Determines whether or not there is an abnormality in the gas supply system based on the degree of matching between both patterns (step S108). If there is no abnormality (N), the process returns to step S104. If there is an abnormality (Y), the gas supply system abnormality detection device
An alarm is issued by the alarm means 46 (step S10
9) Then, the gas shutoff valve 26 shuts off the gas flow path to end the operation. In addition, as a warning method, a warning lamp 39
It is not limited to the above, but a buzzer may be used, or by shutting off the gas flow path by the gas shutoff valve 26,
The gas user may be forcibly notified of the abnormality.

Further, the gas meter 20 is operated to detect a pattern of pressure fluctuations during normal operation (step S in FIG. 4).
If a reset switch for activating steps 101 to S103) is provided, it becomes possible to reset the pressure fluctuation pattern during normal operation when the gas supply system is changed due to remodeling or the like.

As described above, according to the abnormality detecting apparatus for the gas supply system of this embodiment, the sound wave is periodically emitted toward the upstream side of the gas meter 20 in the gas flow path,
Since the pattern of the reflected wave generated by being reflected in the gas supply system is detected, and the abnormality in the gas supply system is detected from the change in the diameter of this pattern, the gas leak in the gas supply system on the upstream side of the gas meter 20 is detected. It is possible to automatically and early detect such abnormalities.

Further, in the abnormality detecting device of the gas supply system of this embodiment, since the abnormality is detected without shutting off the gas, it is possible to detect the abnormality without stopping the gas supply to the customer.

The present invention is not limited to the above embodiment,
For example, in the embodiment, all the constituent elements of the abnormality detection device of the gas supply system are provided in the gas meter 20, but all or some of these constituent elements are provided in the vicinity of the gas meter 20 separately from the gas meter 20. You may. For example,
The loudspeaker 24 and the microphone 25 are arranged inside the lamp inner tube 11 in the vicinity of the gas meter 20,
It may be connected to the control unit 30 of.

The wave caused by the pressure fluctuation is not limited to the audible sound, and may be a compression wave having a frequency lower or higher than that of the audible sound. Further, the pressure fluctuation generating means is not limited to the speaker 24, but may be a proportional valve or an on-off valve that generates a compression wave by opening and closing the gas flow path in a short time.

Further, in the embodiment, the sound wave is emitted toward the upstream side of the gas meter 20 to detect the abnormality in the gas supply system on the upstream side of the gas meter 20.
It is also possible to emit a sound wave toward the downstream side of the gas meter 20 and detect an abnormality in the gas supply system on the downstream side of the gas meter 20. Therefore, according to the present invention, it is possible to detect an abnormality in the gas supply system from the main branch pipe to the gas plug in the house.

[0029]

As described above, according to the abnormality detecting device of the gas supply system of the present invention, the pressure fluctuation generating means for generating the pressure fluctuation in the gas flow path and the pressure generated by the pressure fluctuation generating means. Pressure fluctuation detection means for detecting pressure fluctuations caused by reflected waves generated by fluctuations in the gas supply system, and pressure fluctuation data detected by the pressure fluctuation detection means when the gas supply system is normal Is stored by the storage means, the abnormality determination means compares the pressure fluctuation data detected by the pressure fluctuation detection means during the inspection with the pressure fluctuation data stored by the storage means, and the comparison result indicates the gas supply system Since an abnormality is discriminated, an abnormality such as a gas leak in the gas supply system upstream of the gas meter can be automatically and early detected. An effect that can be.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a gas supply system including an abnormality detection device for a gas supply system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a control unit of the gas meter in FIG. 1 and its peripherals.

FIG. 3 is a block diagram for explaining the function of the abnormality detection device of the gas supply system of FIG.

FIG. 4 is a flow chart for explaining the operation of the abnormality detection device for the gas supply system of FIG.

5 is a characteristic diagram showing an example of a pattern of pressure fluctuations in a normal state detected by the abnormality detection device of the gas supply system of FIG.

6 is a characteristic diagram showing an example of a pattern of pressure fluctuations at the time of abnormality detected by the abnormality detection device of the gas supply system of FIG.

FIG. 7 is an explanatory diagram for explaining a conventional gas supply system.

[Explanation of symbols]

 10 main pipes 11 light inner pipe 20 gas meter 24 speaker 25 microphone 26 gas cutoff valve 30 control unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G08B 21/00 W

Claims (2)

[Claims] 1. A pressure fluctuation generating means for generating a pressure fluctuation in a gas passage through which a gas passes in a gas supply system, and a wave generated by the pressure fluctuation generated by the pressure fluctuation generating means is reflected in the gas supply system. Pressure fluctuation detection means for detecting pressure fluctuations due to reflected waves generated by the above, storage means for storing data of pressure fluctuations detected by the pressure fluctuation detection means when the gas supply system is normal, and the pressure fluctuations during inspection. The pressure fluctuation data detected by the detection means and the pressure fluctuation data stored by the storage means are compared, and an abnormality determination means for determining abnormality of the gas supply system based on the comparison result is provided. Abnormality detection device for gas supply system. 2. The gas supply according to claim 1, wherein the pressure fluctuation generating means and the pressure fluctuation detecting means are provided in a gas meter for measuring a flow rate of the gas passing through the gas flow path. System abnormality detection device.