JPH08128913A - Leak detection device - Google Patents

Abstract

PURPOSE: To make it possible to detect the existence of leak from the supply pipe of fluid such as gas or the like automatically so as to require no hand for inspection. CONSTITUTION: A supply pipe 11 is composed of two portions, that is, an underground buried portion 11a and a ground arranged portion 11b. When a flow quantity becomes a very small quantity, a shut-off valve (V1) 12 and a shut-off valve (V2) 15 are respectively brought in a closed state. Thereafter, the existence of the leak of the supply pipe 11 on the upstream side from second spot B based on the detection result of a pressure sensor (P1) 14 and on the downstream side from the second spot B based on the detection result of a pressure sensor (P2) 17 is respectively detected. The opening and closing of the shut-off valve (V1) 12 and the opening and closing of the shut-off valve (V2) 15 are respectively controlled by a microcomputer 31 and by a microcomputer 18. The transmission of a valve opening and closing signal from the microcomputer 18 to the microcomputer 31 is performed by a communication means via a sound wave composed of a speaker 33 and a microphone 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak detection system for detecting the presence or absence of leakage of fluid such as gas flowing through a supply pipe in a supply pipe.

[0002]

2. Description of the Related Art Generally, a gas meter has a function of measuring the amount of gas used and a safety function of detecting the presence or absence of gas leakage and immediately issuing an alarm when a gas leakage occurs. However, the safety function of this gas meter can detect only gas leaks on the downstream side of the gas meter, that is, between the gas meter and the gas appliance, and on the upstream side of the gas meter, that is, between the road and the home boundary and the gas meter. It was not possible to automatically detect the presence or absence of gas leakage in the supply pipe buried in the ground (between the branch pipe and the gas meter). Therefore, it is obligatory to regularly check for leakage between the main branch pipe and the gas meter by using a special sensor (combustion substance detection sensor).

[0003]

However, in the conventional method, it takes a lot of labor to detect the leak, and in addition, the inspection can be performed only once every three years.

The present invention has been made in view of the above problems, and an object thereof is to automatically and quickly detect the presence or absence of leakage of a fluid such as a gas in a supply pipe, and no human labor for the detection is required. It is to provide a leak detection system that can improve the safety.

[0005]

A leak detection system according to claim 1, wherein a region from a first point to a second point downstream of the first point, and a second point to the second point. The regions up to the third point on the downstream side of the second point are respectively provided at the supply pipe to be the leakage inspection target and at the position corresponding to the first point of the supply pipe, and are set to the open state in the normal state. A first flow path opening / closing means, a second flow path opening / closing means provided at a position corresponding to a second point of the supply pipe, and set to an open state in a normal state; Between a second point and a third point of the supply pipe, which is provided between the second point and the second point, and detects the pressure of the fluid flowing through the supply pipe. Is provided in
Second pressure detecting means for detecting the pressure of the fluid flowing through the supply pipe, flow rate detecting means for detecting the flow rate of the fluid flowing through the supply pipe, and the first pressure detecting means provided near the second point. Communication means including transmitting means for transmitting a valve opening / closing signal to the flow path opening / closing means and receiving means provided near the first point for receiving the valve opening / closing signal transmitted from the transmitting means; The second flow path opening / closing means, the first pressure detecting means, the second pressure detecting means, the flow rate detecting means, and the transmitting means are electrically connected to each other, and the flow rate detected by the flow rate detecting means is less than a predetermined flow rate. When the micro flow rate mode is entered, the second flow path opening / closing means is closed, and a valve closing signal for the first flow path opening / closing means is transmitted via the transmitting means, and then the first flow path opening / closing means is transmitted. 1
The presence or absence of leakage in the region from the first point to the second point of the supply pipe is determined based on the detection result of the pressure detection means of the above, and the supply is performed based on the detection result of the second pressure detection means. The first control means for detecting the presence or absence of leakage in the region from the second point to the third point of the pipe, and the first flow path opening / closing means and the receiving means are electrically connected to each other to receive the signal. And a second control means for closing the first flow path opening / closing means when a valve closing signal is received via the means.

In this leak detection system, when the flow rate detected by the flow rate detection means becomes a minute flow rate, the first flow path opening / closing means and the second flow path opening / closing means are automatically closed, and the supply pipe is sealed. It becomes a state. In this sealed state, the leakage detection means determines the area from the first point to the second point of the supply pipe based on the detection result of the first pressure detection means, and the area from the second point to the third point. For the areas up to the point, leakage inspection is performed based on the detection result of the second pressure detecting means. The opening / closing operation of the second flow path opening / closing means is independently controlled by the first control means, and the opening / closing operation of the first flow path opening / closing means is independently controlled by the second control means. The communication means transmits the valve opening / closing signal to the second control means.

A leakage detection system according to a second aspect is the system according to the first aspect, further comprising an alarm informing means for informing an abnormal state, and when the first control means determines that there is a leakage. The alarm notification means is configured to operate.

According to a third aspect of the present invention, there is provided the leakage detection system according to the second aspect, wherein the alarm informing means gives an alarm based on the detection result of the first pressure detecting means. And a second notifying unit for making a notification different from the first notifying unit based on the detection result of the second pressure detecting means, whereby the supply pipe 2
Alarms are issued individually for each of the two areas.

According to a fourth aspect of the present invention, there is provided the leak detection system according to the second or third aspect, wherein the first control means opens the second flow path opening / closing means after activating the alarm notifying means. When in the state, the valve opening signal for the first flow path opening / closing means is transmitted via the transmitting means, while the second control means receives the valve opening signal via the receiving means, The first flow path opening / closing means is configured to be opened.

The leak detection system according to claim 5 is the system according to any one of claims 2 to 4,
The fluid to be supplied is gas, and the supply pipe is a gas supply pipe between the main branch pipe and the gas meter installed in the house of each consumer.

A leakage detection system according to a sixth aspect is the system according to the fifth aspect, wherein the first control means is electrically connected to a shut-off valve built in the gas meter, and when it is determined that there is a leakage, an alarm is issued. In addition, the shutoff valve in the gas meter is driven to shut off the gas supply.

A leakage detection system according to a seventh aspect is the system according to the fifth or sixth aspect, wherein a region of the supply pipe upstream of a position where the first pressure detecting means is arranged is:
The first flow path opening / closing means, the second control means, and the receiving means are respectively buried in the ground, while the region downstream of the first pressure detecting means is the first pressure detecting means, The second flow path opening / closing means, the flow rate detecting means, the second pressure detecting means, the first controlling means and the transmitting means are arranged on the ground.

In this leak detection system, the first flow path opening / closing means, the second control means and the receiving means may be buried in the ground together with the supply pipe, and other first pressure detecting means,
The second flow path opening / closing means, the flow rate detecting means, the second pressure detecting means, and the transmitting means can be integrally installed at locations on the ground where they can be easily installed.

The leak detection system according to claim 8 is the system according to claim 7, wherein the transmitting means is a speaker installed on a ground portion of the supply pipe, and the receiving means is an underground portion of the supply pipe. The microphone installed in the first control means and the second control means are configured to communicate with each other by using a valve opening / closing signal by a sound wave.

A leak detection system according to a ninth aspect is the system according to the seventh aspect, wherein the transmitting means is an ultrasonic transmitter installed on the ground portion of the supply pipe, and the receiving means is the supply pipe. The ultrasonic receiver is installed in the underground, and is configured to perform communication between the first control means and the second control means by using a valve opening / closing signal based on ultrasonic pulses.

A leak detection system according to a tenth aspect is the system according to the seventh aspect, wherein the transmitting means is an optical transmitter installed on a ground portion of the supply pipe, and the receiving means is an underground portion of the supply pipe. And an optical fiber disposed in the supply pipe, connecting the optical transmitter and the optical receiver between the first control means and the second receiver. It is configured to communicate with the control means by using a valve opening / closing signal by an optical pulse.

The leak detection system according to claim 11 is the system according to claim 7, wherein the transmitting means is a vibration generator installed on a ground portion of the supply pipe, and the receiving means is the ground of the supply pipe. The acceleration sensor is installed in the middle part, and is configured to communicate between the first control means and the second control means by using a valve opening / closing signal due to vibration.

The leak detection system according to claim 12 is the system according to any one of claims 5 to 11, wherein the first control means further comprises a communication means, and the communication means measures the meter through a telephone line. It is connected to a center and configured to notify the meter reading center of the occurrence of gas leakage.

[0019]

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

FIG. 1 shows a schematic configuration of a leak detection system according to an embodiment of the present invention. The leak detection system of the present embodiment is for detecting the presence or absence of gas leakage upstream of the gas meter (between the main branch pipe and the gas meter).
It is composed of the above-ground installation device 13 and the underground burying device 30.

The leak detection system 10 is attached to a supply pipe (channel diameter is, for example, 5 cm) 11 for supplying gas from a main branch pipe to a gas meter (not shown). The supply pipe 11 is an underground buried portion 11 which is buried underground.
a, and a ground installation portion 11b installed on the ground in a region near a gas meter (not shown) on the downstream side. The supply pipe 11 is an underground buried portion 11
From a position in the vicinity of the main branch pipe (not shown) of a (hereinafter, this position is referred to as a first point A) to an appropriate position of the above-ground installation portion 11b (hereinafter, this position is referred to as a second point B). And a region from the second point to a position in the vicinity of a gas meter (not shown) (hereinafter, this position is referred to as a third point C) are gas leak inspection targets in the present system.

At the first point A of the underground buried portion 11a of the supply pipe 11, a shutoff valve (V1) 12 is installed as a first flow path opening / closing means. This shutoff valve (V1) 1
Reference numeral 2 is a bidirectional valve that can electrically shut off and open the gas flow path, and is set to an open state in a normal state.

In the underground buried portion 11a of the supply pipe 11, a microphone 32 as a receiving means for receiving a valve opening / closing signal from a speaker 33, which will be described later, is further installed near the first point A. ing. This microphone 32 is a microcomputer 3 as a second control means.
1, and supplies the received valve opening / closing signal to the microcomputer 31. The shut-off valve (V1) 12, the microphone 32, and the microcomputer 31 are integrated with the underground installation portion 11a of the supply pipe 11 to form an underground burying device 30.

On the other hand, the above-ground installation portion 11 of the supply pipe 11
A cutoff valve (V2) 15 as a second flow path opening / closing means is installed at a position corresponding to the second position B of b. The shut-off valve (V2) 15 is a bidirectional valve like the shut-off valve (V1) 12, and is normally set to the open state. At the ground installation portion 11b between the first point A and the second point B of the supply pipe 11, the shutoff valve (V
2) First to detect the gas pressure in the region upstream of 15
A pressure sensor (P1) 14 as a pressure detecting means is provided. The second point B and the third point C of the supply pipe 11
A pressure sensor (P2) 17 as a second pressure detecting means for detecting the gas pressure in a region downstream of the shutoff valve (V2) 15 in the supply pipe 11 is provided in the above-ground portion 11b between It is arranged. Further, a flow meter 16 as a flow rate detecting means for detecting the flow rate of the gas flowing through the supply pipe 11 is provided between the shutoff valve (V2) 15 and the pressure sensor (P2) 17. The flow meter 16 is composed of a sensor capable of measuring a flow rate in the range of 0 to several tens m ³ / h.

The above-grounded portion 11b of the supply pipe 11 further serves as a transmission means for transmitting a valve opening / closing signal by sound waves to the microphone 32 at a position near the upstream side of the pressure sensor (P2) 17. A speaker 33 is installed.

The shutoff valve (V1) 12, the pressure sensor (P
1) 14, the shutoff valve (V2) 15, the flow meter 16, the pressure sensor (P2) 17 and the speaker 33 are connected to a microcomputer 18 as a first control means for controlling the operation of each part. Microcomputer 1
Reference numeral 8 also has a function as a leak detecting means for detecting a gas leak in the supply pipe 11 based on the output signals of the pressure sensor (P1) 14, the flow meter 16 and the pressure sensor (P2) 17. That is, the shut-off valve (V2) 15 is closed when the flow rate detected by the flow meter 16 is in the minute flow rate mode which is less than the predetermined flow rate (the ignition flow rate of the gas appliance used on the downstream side). A valve closing signal for closing the shutoff valve (V1) 12 is transmitted to the microphone 32 via the speaker 33. In the microcomputer 31, when the microphone 32 receives the valve closing signal, the shutoff valve (V1) 12 is closed,
Cut off the gas flow path. And the microcomputer 1
In Fig. 8, after the shut-off valve (V1) 12 is closed, the leakage of the leakage from the first point A to the second point B of the supply pipe 11 is detected based on the detection result of the pressure sensor (P1) 14. The presence / absence is determined and the presence / absence of leakage in the region from the second point B to the third point C of the supply pipe 11 is detected based on the detection result of the pressure sensor (P2) 17.

Here, to determine whether or not there is a leak, specifically, first, the shutoff valve (V1) 12 and the shutoff valve (V2) 1
After closing 5 respectively, pressure sensor (P2) 17
Based on the detection result of, the pressure drop state in the region downstream of the shutoff valve (V2) 15 is monitored to determine whether there is a possibility of leakage (that is, whether the pressure drop state is steep). to decide. That is, if there is a sharp pressure drop, it is highly likely that a gas appliance on the downstream side is being used, while
If the pressure does not drop sharply but drops gradually, it is possible to distinguish from the possibility of gas leakage. Therefore, in the present embodiment, if the pressure does not show a sharp drop, it is considered that there is a possibility of leakage, and the pressure detected by the pressure sensor (P1) 14 and the pressure sensor (P2) 17 is maintained for a predetermined time. The number of decreases is counted, and when the count value (pressure decrease number value) exceeds a predetermined value (reference value), it is determined that there is leakage in the corresponding region. Note that the value of the number of times of pressure decrease is calculated by the pressure sensor (P1) 14
2) It is stored in the RAM 182 for each 17 and is set to “0” at the start of the leakage inspection, and is rewritten so as to be incremented by +1 each time a pressure drop is detected.

The microcomputer 18 also has an alarm notification section 19 as an alarm notification means for notifying an abnormal state.
Is connected. The alarm notification unit 19 is composed of, for example, a lamp that gives a display alarm by lighting or blinking, or a voice generating device that gives a voice call alert. When it is determined that there is a gas leak, the microcomputer 18 drives the alarm notifying unit 19 to prompt the customer or service person to recover. The alarm notifying unit 19 includes a first notifying unit 19a for notifying a gas leak in a region from the first point A to the second point B of the supply pipe 11, and the second point B of the supply pipe 11. The second notification unit 19b is provided to notify the gas leak in the area up to the third point C. Although not shown, the alarm notification unit 19 may also be used as an alarm device attached to a gas meter on the downstream side.

A power source 20 is connected to the microcomputer 18. As the power source, commercial power source, battery,
Although a solar cell or the like can be used, the main body portion of the apparatus including the microcomputer 18 can be installed on the outer wall surface of the house, and in this case, it is preferable to drive the solar cell. The solar cell and the battery or the commercial power source may be used together.

The microcomputer 18 is connected to a telephone line via a communication controller 40 for controlling switching with a telephone, and further connected via a switch 50 to a host computer 61 installed in an automatic meter reading center 60. When the microcomputer 18 is connected and gas leakage is detected, the fact is notified to the host computer 61.

In this embodiment, the microcomputer 18, the alarm notifying section 19, the power source 20, and the shutoff valve (V
1) 12, pressure sensor (P1) 14, shutoff valve (V2) 1
5, the above-ground installation unit 11b of the supply pipe 11 including the flow meter 16, the pressure sensor (P2) 17 and the speaker 33 is integrated to form the above-ground installation device 13.

FIG. 2 is a block diagram showing the configuration of the microcomputer 18 as the first control means of the leak detection system 10 and its peripherals. Microcomputer 18
Is a CPU (central processing unit) 180, a ROM (read
An only memory (181), a RAM (random access memory) 182, a clock 183 for clocking, and an input / output port 184 are provided, and these are connected to each other by a bus 185. The input / output port 184 has a pressure sensor (P1) 14, a pressure sensor (P2) 17, and a flow meter 1
6, a speaker 33, a drive circuit 21 for driving the shut-off valve (V2) 15, and a notification section drive circuit 22 for driving the alarm notification section 19 are connected to each other. In the microcomputer 18, the CPU 180 has a RAM
The function as the leak detection system 10 is realized by executing the program stored in the ROM 181 with 182 as a working area.

On the other hand, the microcomputer 31 as the second control means is provided with a shutoff valve (V1) as shown in FIG.
A valve drive circuit 34 for driving 12 and a microphone 32 are connected.

Next, the leak detection system 1 according to the present embodiment.
The operation of 0 will be described with reference to the flowcharts shown in FIGS. Note that FIG. 4 is for explaining the operation on the side of the above-mentioned ground arrangement section 13, and FIG. 5 is for explaining the operation on the side of the underground buried section 30.

In this leakage detection system 10, in the normal state, the shutoff valve (V1) 12 and the shutoff valve (V2)
Both 15 are in an open state, and the gas supplied from the main branch pipe (not shown) goes to the gas meter (not shown) side installed in the house through the underground buried portion 11a and the above-ground installation portion 11b of the supply pipe 11. Is being supplied. In this state, the leak detection system 10 monitors the flow rate detected by the flow meter 16 by the microcomputer 18 in the system body 13 (step S401). Then, when the flow rate of gas in the supply pipe 11 becomes smaller than a predetermined ignition flow rate (for example, 300 liters / h), the flow rate becomes small (step S4).
01; Y), shutoff valve (V1) 12 and shutoff valve (V2)
A valve closing signal for 15 is output (step S40).
2). As a result, the shut-off valve (V2
) 15 is closed and the gas flow path is blocked (step S403). A valve closing signal for the shutoff valve (V1) 12 is transmitted as a sound wave from the speaker 33 and propagates in the supply pipe 11 as indicated by an arrow (broken line) in FIG.
Then, this valve closing signal is received by the microphone 32 on the side of the underground burying device 30 (step S501; Y).
Then, the microcomputer 31 closes the shutoff valve (V1) 12 to shut off the gas flow path (step S50).
2).

As a result, between the first point A and the second point B of the supply pipe 11, and between the second point B and the third point C.
The space between and is sealed. In this embodiment, the pressure drop state in each region is monitored in this state, and the presence or absence of gas leakage is determined in parallel. When the gas flow rate in the supply pipe 11 is not in the predetermined minute flow rate mode (step S401; N), the above determination is repeated after the predetermined waiting time (step S414).

Shutoff valve (V1) 12 and shutoff valve (V2)
After both 15 are closed, the leakage detection system 10
Then, in response to the detection result of the pressure sensor (P2) 17, it is first determined whether or not there is a sharp pressure drop (step S404). If there is a steep pressure drop (Y), it is assumed that the gas appliance on the downstream side is used, and both the shutoff valve (V1) 12 and the shutoff valve (V2) 15 are returned to the open state. Output an open signal (step S
411). As a result, the shut-off valve (V2) 15 is opened on the side of the above-grounded device 13 to open the gas passage (step S412). Further, the valve opening signal for the shutoff valve (V1) 12 is transmitted as a sound wave from the speaker 33 and propagates in the supply pipe 11 as in the case of the valve closing signal. Then, when the valve opening signal is received by the microphone 32 on the side of the underground burying device 30 (step S503; Y),
The microcomputer 31 opens the shut-off valve (V1) 12 and opens the gas passage (step S504).

On the other hand, when there is no abrupt pressure drop (step S404; N), there is almost no pressure drop and there is no gas leak, or there is a gas pressure drop where there is a gas leak. As the pressure sensor (P
The pressures detected by 1) 14 and the pressure sensor (P2) 17 are monitored (step S405), and it is determined whether or not the pressure is reduced (step S406). When the pressure detected by the pressure sensor (P1) 14 or the pressure sensor (P2) 17 respectively decreases (Y), the count value (pressure decrease frequency value) of the sensor on which the pressure has decreased is counted by +1. Up (step S4
06). Next, it is determined for each sensor whether or not the value of the number of pressure drops has reached a predetermined reference value (step S40).
8) If neither of them has reached the reference value (N), the process proceeds to step S411, and both the shutoff valve (V1) 12 and the shutoff valve (V2) 15 are returned to the open state. After that,
After a predetermined waiting time (step S413), step S
The processing shifts to 401, and the above operation is repeatedly executed.

If the number of times of the pressure drop by at least one of the pressure sensor (P1) 14 and the pressure sensor (P2) 17 has reached the reference value (step S408; Y), the area corresponding to the sensor that has reached the reference value. If a gas leak occurs at the alarm unit drive circuit 22, an alarm signal is output to the first alarm unit 19a and the second alarm unit 19b.
Among them, the corresponding notifying unit is operated, and the fact is notified to the automatic meter reading center 60 via the communication controller 40. At the same time, the value of the number of pressure drops stored in the RAM 182 is cleared (step S409). continue,
Both the shutoff valve (V1) 12 and the shutoff valve (V2) 15 are returned to the open state, and a predetermined waiting time (step S413)
After that, the process proceeds to step S401, and the above operation is repeatedly executed.

When the pressures detected by the pressure sensor (P1) 14 and the pressure sensor (P2) 17 do not decrease in step S406 (N),
RAM1 with or without gas leak
The value of the number of pressure drops stored in 82 is cleared, the output of the alarm signal is stopped (step S410), and then the process proceeds to step S411.

As described above, the leak detection system 1 of this embodiment
At 0, the presence or absence of gas leakage can be automatically detected under the control of the microcomputer 18. Therefore, the conventional manual inspection work becomes unnecessary, and the presence or absence of gas leakage can be constantly monitored, so that the safety function is improved.

Moreover, in the leak detection system 10, the supply pipe 11 to be inspected is divided into two at the second point B (installation position of the shutoff valve (V2) 15) at the time of inspection, and the upstream side and the downstream side thereof. Since the gas leakage inspection is performed simultaneously on the side independently of each other, the inspection time is significantly shortened. Further, the alarm notifying unit 19 is also divided into a first notifying unit 19a and a second notifying unit 19b, and the alarm notifying unit 19 is activated according to the detection results of the pressure sensor (P1) 14 and the pressure sensor (P2) 17, respectively. Since this is done, the location of the leak can be easily estimated.

Further, in this embodiment, the entire system is divided into two, that is, the above-ground installation device 13 and the underground buried portion 30, and each has a control function and a sound wave communication function. Therefore, wiring between the underground part and the above-ground part is unnecessary, and since only the shutoff valve (V1) 12, the microphone 32 and the microcomputer 31 need to be buried, the excavation holes for system installation are compared. It can be small, and the installation work will be easy.

Further, in this embodiment, since the occurrence of gas leakage can be automatically notified to the automatic meter reading center 60, it becomes easy to centrally manage a large number of supply pipes 11.

In the above embodiment, when a gas leak occurs, a shut-off valve (V
Although 1) 12 and the shutoff valve (V2) 15 are returned to the open state, respectively, they may be left in the closed state as they are. Alternatively, the microcomputer 18 is electrically connected to a gas meter (not shown) on the downstream side, and when there is a gas leak, the shutoff valve inside the gas meter is driven by a notification from the microcomputer 18. May be.

The present invention has been described with reference to the examples.
The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above-described embodiment, the speaker 33 is used for the communication between the above-ground arrangement portion 13 and the underground buried portion 30.
Although the sound waves are generated by using the microphone 32 and the microphone 32, other methods such as those shown in FIGS. 6 to 8 may be used.

In the method shown in FIG. 6, the transmitting means is the supply pipe 1.
The ultrasonic transmitter 40 installed on the ground part 1 and the receiving means are composed of the ultrasonic receiver 41 installed in the underground part of the supply pipe 11, and the microcomputer 18 and the microcomputer 30 are provided. During this period, communication is performed using a valve opening / closing signal based on ultrasonic pulses. This method distinguishes between open and closed signals, for example:
In the case of a valve opening signal, one ultrasonic pulse is used, and in the case of a valve closing signal, a plurality of ultrasonic pulses are arranged at predetermined intervals.

In the method shown in FIG. 7, the transmitting means is composed of the optical transmitter 42 and the receiving means is composed of the optical receiver 43, and the space between the optical transmitter 42 and the optical receiver 43 is arranged in the supply pipe 11. The optical fibers 44 are connected by an optical fiber 44 provided, and communication is performed by using a valve opening / closing signal by an optical pulse.

In the method shown in FIG. 8, an acceleration sensor for detecting vibration generated in the supply pipe 11 by the vibration generator 45 is used for the transmitting means and the vibration generator 45 for generating vibration by a motor or the like. 46, which communicates using a valve opening / closing signal due to vibration. In this method, the state is reversed by receiving a signal (for example, when the shutoff valve (V1) 12 is closed, the state is reversed and when the shutoff valve (V1) 12 is opened, the state is reversed).

Since the function and effect of the leak detection system 10 are the same in any of the methods shown in FIGS. 6 to 8, the description thereof will be omitted.

The present invention has been described with reference to the examples.
The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above-described embodiment, between the present device and the automatic meter reading center 60, the automatic meter reading center 60 side is notified only when a gas leak occurs.
1 and the microcomputer 18 are enabled for bidirectional communication, and the host computer 6 performs an instruction operation for starting the detection and the like.
The instruction may be given from the first side. According to such a configuration, it is possible to perform the leak detection intermittently every arbitrary period by the control from the center, and the power consumption of the power source 20 such as the solar cell can be reduced.

[0052]

As described above, according to the first to the twelfth aspects.
According to the leak detection system described above, the area from the first point to the second point of the supply pipe to be inspected is based on the detection result of the first pressure detecting means, and from the second point. Since the area up to the third point is subjected to the leakage inspection based on the detection result of the second pressure detecting means, the leakage state in the supply pipe can be automatically detected in parallel in the two areas. Therefore, it is possible to eliminate the need for manpower for detection, it is possible to constantly monitor the presence or absence of leakage, and the detection accuracy is good, so that the safety is greatly improved. Further, since the supply pipe to be inspected is divided into two parts and the inspections are performed at the same time, there is an effect that the inspection time can be shortened. Further, the opening / closing operation of the second flow path opening / closing means is independently controlled by the first control means, and the opening / closing operation of the first flow path opening / closing means is independently controlled by the second control means, and
Since the valve opening / closing signal is transmitted from the first control means to the second control means via the communication means, electrical wiring between the two regions is unnecessary.

Further, in particular, according to the leakage detection system of the seventh aspect, only the first flow path opening / closing means, the second control means and the receiving means need be buried in the ground, and the other portions are on the ground. Since it can be installed in a small area, a small excavation hole for installing the system is required, and the installation work is facilitated.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a leak detection system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of first control means and its periphery in the leak detection system of FIG.

FIG. 3 is a block diagram showing a circuit configuration of second control means and its periphery in the leak detection system of FIG.

FIG. 4 is a flowchart for explaining the operation of the ground detection apparatus side of the leak detection system of FIG.

5 is a flowchart for explaining the operation of the underground detection apparatus side of the leak detection system of FIG.

6 is a main part configuration diagram showing another example of a communication unit in the leak detection system of FIG. 1. FIG.

7 is a main part configuration diagram showing still another example of a communication unit in the leak detection system of FIG. 1. FIG.

8 is a main part configuration diagram showing still another example of a communication unit in the leak detection system of FIG. 1. FIG.

[Explanation of symbols]

 10 Leakage detection system 11 Supply pipe 11a Underground buried part 11b Ground installation part 12 Shutoff valve (V1) (first flow path opening / closing means) 13 Ground installation device 14 Pressure sensor (P1) (first pressure detection means) ) 15 shutoff valve (V1) (second flow path opening / closing means) 16 flow meter (flow rate detecting means) 17 pressure sensor (P2) (second pressure detecting means) 18 microcomputer (first control means) 19 alarm Notification unit (warning notification unit) 19a First notification unit 19b Second notification unit 30 Underground device 31 Microcomputer (second control unit) 32 Microphone (reception unit) 33 Speaker (transmission unit) 60 Automatic meter reading center

Claims (12)

[Claims] 1. An area from a first point to a second point downstream of the first point, and a second point to a third point downstream of the second point. Each of the regions has a supply pipe to be a leakage inspection target, a first flow path opening / closing means which is provided at a position corresponding to a first point of the supply pipe, and is set to an open state in a normal state, and the supply pipe. It is provided between a first point and a second point of the supply pipe, which is provided at a location corresponding to the second location and which is set to an open state in a normal state, and the first location of the supply pipe. A first pressure detecting means for detecting the pressure of the fluid flowing through the supply pipe, and a pressure of the fluid flowing through the supply pipe provided between the second point and the third point of the supply pipe. Second pressure detecting means, and flow rate detecting means for detecting the flow rate of the fluid flowing through the supply pipe. Transmitting means provided near the second point for transmitting a valve opening / closing signal to the first flow path opening / closing means and a valve provided near the first point and transmitted from the transmitting means Communication means including a receiving means for receiving an opening / closing signal, and the second flow path opening / closing means, the first pressure detecting means, the second pressure detecting means, the flow rate detecting means, and the transmitting means are electrically connected. When the flow rate detected by the flow rate detection means is in a minute flow rate mode in which the flow rate is less than a predetermined flow rate, the second flow path opening / closing means is closed and the first flow path is transmitted via the transmitting means. A valve closing signal is transmitted to the passage opening / closing means, and then the presence or absence of leakage in the area from the first point to the second point of the supply pipe is determined based on the detection result of the first pressure detecting means. , The second pressure detection First control means for detecting the presence or absence of leakage in the region from the second point to the third point of the supply pipe based on the detection result of the means; each of the first flow path opening / closing means and the receiving means. And a second control means that is electrically connected to the first flow path opening / closing means when the valve closing signal is received via the receiving means. . 2. The alarm notification means for notifying an abnormal state is further provided, and the alarm notification means is operated when the first control means determines that there is a leak. Leak detection system. 3. The alarm notification means includes a first notification section that performs notification based on the detection result of the first pressure detection means, and a first notification based on the detection result of the second pressure detection means. The leak detection system according to claim 2, further comprising a second notification unit that performs notification different from the unit. 4. The first control means opens the second flow path opening / closing means after actuating the alarm notifying means and opens the first flow path opening / closing via the transmitting means. The second control means, when receiving the valve open signal via the receiving means, opens the first flow path opening / closing means while transmitting a valve open signal to the means. The leak detection system according to claim 2. 5. The fluid to be supplied is gas, and the supply pipe is a gas supply pipe between the main branch pipe and a gas meter installed in a house of each customer. The leak detection system according to any one of 1. 6. The first control means is electrically connected to a shut-off valve built in the gas meter, issues an alarm when it is determined that there is a leak, and drives the shut-off valve inside the gas meter to supply gas. 6. The leak detection system according to claim 5, wherein the leak detection system is configured to shut off. 7. An area of the supply pipe upstream of a position where the first pressure detecting means is arranged is buried in the ground together with the first flow path opening / closing means, the second control means and the receiving means. On the other hand, the region downstream of the first pressure detecting means has the first pressure detecting means, the second flow path opening / closing means, the flow rate detecting means, the second pressure detecting means, the first control means, and 7. The leak detection system according to claim 5, wherein the leak detection system is arranged on the ground together with each of the transmitting means. 8. The transmitting means is a speaker installed in the ground portion of the supply pipe, and the receiving means is a microphone installed in the underground portion of the supply pipe, and the first control means and the first control means are provided. 8. The leak detection system according to claim 7, wherein communication is performed with the second control means by using a valve opening / closing signal based on a sound wave. 9. The transmitting means is an ultrasonic transmitter installed on the ground part of the supply pipe, and the receiving means is an ultrasonic receiver installed on the underground part of the supply pipe. 8. The leak detection system according to claim 7, wherein communication is performed between the first control means and the second control means by using a valve opening / closing signal based on an ultrasonic pulse. 10. The transmitting means is an optical transmitter installed on the aboveground part of the supply pipe, and the receiving means is an optical receiver installed on the underground part of the supply pipe, and the optical transmitter. And an optical receiver are connected by an optical fiber arranged in the supply pipe, and the first control means and the second control means are connected.
The leak detection system according to claim 7, wherein communication is performed with the control means of (1) using a valve opening / closing signal by an optical pulse. 11. The transmission means is a vibration generator installed on the ground part of the supply pipe, and the reception means is an acceleration sensor installed on the ground part of the supply pipe, and the first control is provided. The communication between the means and the second control means is performed by using a valve opening / closing signal due to vibration.
Leak detection system described. 12. A communication means is further provided, wherein the communication means is connected to a meter-reading center through a telephone line and configured to notify the meter-reading center of the occurrence of gas leakage. One of
Leakage detection system described in.