JPH08128914A - Leak detection device - Google Patents

Abstract

PURPOSE: To require no hand for detection, and improve safety by making it possible to automatically detect the existence of gas leak from an underground buried supply pipe among a main and branch pipe and a gas meter. CONSTITUTION: A main valve 13 is made in a closed state and a sub-valve 15 is made in an open state by a microcomputer 17 when a flow quantity detected through a flow meter (B) 14 is brought in a very small flow quantity mode less than a predetermined flow quantity. Thereby, a fluid flow is switched from a supply pipe 11 to a branch pipe 12 side. Thereafter, the existence of gas leak is judged based on the detection result of a very small quantity flow meter (A) 16. When the existence is determined, the sub-valve 15 is also brought in the closed state so as to completely shut off a flow path. In the case of no existence determination, the gas flow is switched from the branch pipe 12 to the supply pipe 11 side by making the main valve 13 in the open state and making the sub-valve 15 in the closed state when the flow quantity detected through the very small quantity flow meter (A) 16 becomes larger than the predetermined flow quantity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak detection device for detecting the presence or absence of leakage of a fluid flowing through a supply pipe having a predetermined flow passage diameter in the 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 be able to automatically detect the presence or absence of a leak in a supply pipe buried underground, and to eliminate the need for manpower for the detection. Another object is to provide a leak detection device that can be improved in safety.

[0005]

According to the first aspect of the present invention,
A leak detection device for detecting the presence or absence of leakage in the supply pipe of a fluid flowing through a supply pipe having a predetermined flow passage diameter, having a flow passage diameter smaller than the supply pipe,
A branch pipe for branching the flow of the fluid from a first point in the middle of the supply pipe, and then guiding the branched flow to a second point downstream of the first point of the supply pipe. , When the flow rate of the fluid flowing through the supply pipe is in a minute flow rate mode below a predetermined flow rate, the flow of the fluid between the first point and the second point is changed from the supply pipe to the branch pipe side. A flow path switching means for switching and a leak detection means for detecting the presence or absence of leakage based on the flow state in the branch pipe after the flow of the fluid is switched to the side of the branch pipe by the flow channel switching means.

In this leak detection device, when the flow rate of the fluid flowing through the supply pipe is in the minute flow mode in which the flow rate is less than a predetermined flow rate,
The flow path switching means switches the flow of fluid such as gas to the side of the branch pipe. After that, the leakage detection means detects the presence or absence of leakage based on the flow state in the branch pipe.

The invention according to claim 2 is a leak detection device for detecting the presence or absence of leakage of fluid flowing through a supply pipe having a predetermined flow path diameter in the supply pipe, the leakage detection device being more than the supply pipe. Having a small flow path diameter, after branching the flow of the fluid from the first point in the middle of the supply pipe, the branched flow is at a second point downstream of the first point of the supply pipe. For branching to the branch pipe, a first flow path opening / closing means provided in the branch pipe and set to a closed state in a normal state, and a flow amount of a fluid flowing in the branch pipe provided in the branch pipe. A first flow rate detecting means and a first of the supply pipe
And a second flow path opening / closing means which is provided between the second point and the second point and which is normally set to the open state, and the supply pipe which is provided on the downstream side of the second point of the supply pipe. Second flow rate detecting means for detecting the flow rate of the fluid flowing through the flow path, alarm informing means for informing an abnormal state, and a minute flow rate mode in which the flow rate detected by the second flow rate detecting means is less than a predetermined flow rate. When this occurs, the second flow path opening / closing means is closed and the first flow path opening / closing means is opened to switch the fluid flow from the supply pipe to the branch pipe side, and then the first flow rate detection is performed. The presence or absence of fluid leakage is determined based on the detection result of the means, and when it is determined that there is leakage, the alarm notifying means is activated, while when it is determined that there is no leakage, the first flow rate detecting means or the second flow rate. Flow rate detected by the detection means When the flow rate exceeds a predetermined flow rate, the second flow path opening / closing means is opened, and the first flow path opening / closing means is closed to control the flow of fluid from the branch pipe to the supply pipe side. Is equipped with.

In this leak detecting device, when the flow rate detected by the second flow rate detecting means installed in the supply pipe is in the minute flow mode of less than the predetermined flow rate, The flow path opening / closing means is closed and the first flow path opening / closing means installed in the branch pipe is opened to switch the flow of fluid from the supply pipe to the branch pipe side. After that, the presence or absence of fluid leakage is determined based on the detection result of the first flow rate detecting means. When it is judged that there is a leak,
An alarm is issued by the alarm informing means. On the other hand, when it is determined that there is no leakage, when the flow rate detected by the first flow rate detecting means or the second flow rate detecting means becomes larger than the predetermined flow rate, the second flow path opening / closing means is opened and the second flow path opening / closing means is opened. The passage opening / closing means 1 is closed, whereby the flow of the fluid is switched from the branch pipe to the supply pipe side, and the normal state is restored.

According to a third aspect of the present invention, in the leak detection device according to the second aspect, when the control means determines that there is a leak, the first flow path opening / closing means is closed to shut off the flow path. It was done.

According to a fourth aspect of the present invention, there is provided a leakage detection device for detecting the presence or absence of leakage of fluid flowing through a supply pipe having a predetermined flow passage diameter in the supply pipe, the leakage detection device being more than the supply pipe. Having a small flow path diameter, after branching the flow of the fluid from the first point in the middle of the supply pipe, the branched flow is at a second point downstream of the first point of the supply pipe. For branching to the branch pipe, a first flow path opening / closing means provided in the branch pipe and set to a closed state in a normal state, and a flow amount of a fluid flowing in the branch pipe provided in the branch pipe. First flow rate detecting means, pressure detecting means for detecting the pressure of the fluid flowing through the branch pipe at a position downstream of the first flow path opening / closing means, first point of the supply pipe, and It is provided between the two points and is normally set to open. Second flow path opening / closing means, second flow rate detecting means provided downstream of the second point of the supply pipe for detecting the flow rate of the fluid flowing through the supply pipe, and for notifying an abnormal state The second flow path opening / closing means is closed when the flow rate detected by the alarm notification means and the second flow rate detection means is in a minute flow mode in which the flow rate is less than a predetermined flow rate, and the first flow path is closed. When the opening / closing means is opened to switch the fluid flow from the supply pipe to the branch pipe side, and then the flow rate detected by the first flow rate detecting means becomes close to zero, the first flow path is set. The opening / closing means is closed, and in this state, the presence or absence of fluid leakage is determined based on the detection result of the pressure detecting means. When it is determined that there is leakage, the alarm notifying means is activated, while it is determined that there is no leakage. Sometimes the first flow rate detecting means Thus the flow rate to be detected and a control means for controlling so as to switch the second flow path shutter means to be larger than the predetermined flow rate a flow of fluid to the supply pipe side as the open state.

In this leakage detecting device, the second flow path opening / closing means is closed when the flow rate detected by the second flow rate detecting means installed in the supply pipe is in the minute flow rate mode of less than a predetermined flow rate. With this, the first flow path opening / closing means installed in the branch pipe is opened, and the fluid flow is switched from the supply pipe to the branch pipe side. After that, when the flow rate detected by the first flow rate detecting means becomes a flow rate close to zero (that is, the gas appliance on the downstream side is in a state of igniting or below), the first flow path opening / closing means is closed. The downstream side of the first flow path opening / closing means is sealed. In this state, the presence or absence of fluid leakage is determined based on the detection result of the pressure detecting means.
Then, when it is determined that there is a leak, the alarm notification means issues an alarm notification. On the other hand, when it is determined that there is no leakage, when the flow rate detected by the first flow rate detection means becomes larger than the predetermined flow rate, the second flow path opening / closing means is opened and the fluid flow switches to the supply pipe side. Return to normal state.

According to a fifth aspect of the present invention, there is provided a leakage detection device for detecting the presence / absence of leakage of a fluid flowing through a supply pipe having a predetermined flow passage diameter in the supply pipe. Having a small flow path diameter, after branching the flow of the fluid from the first point in the middle of the supply pipe, the branched flow is at a second point downstream of the first point of the supply pipe. A branch pipe for guiding to, a flow path opening / closing means which is provided between a first point and a second point of the supply pipe and which is set to an open state in a normal state, and provided in the branch pipe,
Flow rate detecting means for detecting the flow rate of the fluid flowing through the branch pipe,
When the flow rate detected by the flow rate detecting means is in a minute flow rate mode below a predetermined flow rate, the flow passage opening / closing means is closed to switch the flow of fluid from the supply pipe to the branch pipe side, and then the flow rate detecting means. If it is determined that there is a leak, an alarm is issued, and if it is determined that there is no leak, the flow rate detected by the flow rate detecting means becomes larger than a predetermined flow rate. And a control means for controlling the flow of the fluid to be switched to the supply pipe side by opening the flow path opening / closing means.

In this leakage detecting device, when the flow rate detected by the flow rate detecting means installed in the branch pipe is in the minute flow rate mode of less than a predetermined flow rate, the flow path opening / closing means installed in the supply pipe is closed. Then, the fluid flow switches from the supply pipe to the branch pipe side. Then, the presence or absence of fluid leakage is determined based on the detection result of the flow rate detecting means. When it is determined that there is a leak, an alarm is issued, while when it is determined that there is no leak, if the flow rate detected by the flow rate detection means becomes larger than a predetermined flow rate, the flow path opening / closing means is opened and the fluid flow Switches from the branch pipe to the supply pipe side.

The invention according to claim 6 is the invention according to claims 2 to 5.
In the leakage detection device according to any one of items 1 to 3, the main body including the control means is installed on an outer wall surface of a house, and a solar cell is used as a power source thereof.

The invention according to claim 7 is the invention according to claims 2 to 6.
In the leak detection device according to any one of items 1 to 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. It was done.

According to an eighth aspect of the present invention, in the leak detection apparatus according to the seventh aspect, the control means is electrically connected to a shut-off valve built in the gas meter, and when it is determined that there is a leak, an alarm is given. The shutoff valve in the gas meter is driven to shut off the gas supply.

The invention according to claim 9 is the invention according to claim 7 or 8.
The leak detection apparatus described above further comprises a communication unit, wherein the communication unit 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.

[0018]

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

First, prior to the description of a specific embodiment,
The basic configuration of the present invention will be described with reference to FIG. The leak detection device of the present invention detects whether or not a fluid such as a gas flowing through the supply pipe 1 having a flow path diameter of a predetermined size leaks in the supply pipe 1. Is also provided with a branch pipe 2 having a small flow path diameter. The leak detection device further includes a flow path switching for switching the flow of the fluid from the supply pipe 1 to the branch pipe 2 when the flow rate of the fluid flowing through the supply pipe 1 is in a minute flow rate mode below a predetermined flow rate. Means 3 and leak detection means 4 for detecting the presence or absence of leakage based on the flow state in the branch pipe 2 after the flow of the fluid is switched to the side of the branch pipe 2 by the flow path switching device 3.

In this leak detecting device, when the flow rate of the fluid flowing through the supply pipe 1 becomes smaller than a predetermined flow rate mode, the flow passage switching means 3 causes the flow of the fluid such as gas from the supply pipe 1 to the branch pipe 2 side. Switch to. Then, in this state, the leakage detection means 4 detects the presence or absence of leakage in the supply pipe 1 based on the flow state in the branch pipe 2. That is, the leak detection is performed by switching the flow of the fluid from the side of the supply pipe 1 having a large flow path diameter to the side of the branch pipe 12 having a small flow path diameter with good leakage detection accuracy.

FIG. 1 shows a schematic configuration of a leak detection device according to a first embodiment of the present invention. The leak detection device of the present embodiment detects the presence or absence of gas leakage upstream of the gas meter (between the main branch pipe and the gas meter).

This leak detection device 10 is attached to a supply pipe 11 buried in the ground between the main branch pipe and the gas meter, and has a branch pipe 12 having a flow passage diameter smaller than that of the supply pipe 11. Is equipped with. This branch pipe 12
Is located in the middle of the supply pipe 11 (hereinafter,
This position is connected to a first point), while the gas inlet 12b is connected to a point downstream of the first point of the supply pipe 11 (hereinafter referred to as a second point), A part of the gas flowing to the gas meter side through the pipe 11 is branched from the first point and then introduced into the supply pipe 11 again at the second point. In this embodiment, the presence or absence of gas leakage in the branch pipe 12 is detected with high accuracy. The flow path diameter of the supply pipe 11 is, for example, 5 cm, and that of the branch pipe 12 is, for example, 2 cm.
set to cm.

The branch pipe 12 is provided with a child valve 15 as a first passage opening / closing means. This child valve 15 is set to the closed state in the normal state. This child valve 15 is composed of a bidirectional valve that can electrically shut off and return. Further, a minute flow meter (A) 16 as a first flow rate detecting means for detecting the flow rate of the gas flowing through the branch pipe 12 is installed in the branch pipe 12 on the downstream side of the child valve 15. . The minute flow meter (A) 16 is, for example, 0 to 50.
It is composed of a sensor capable of measuring a flow rate in the range of 0 liter / h, for example, a flow sensor.

On the other hand, on the supply pipe 11 side, there are a first point and a second point.
A main valve 13 as a second flow path opening / closing means is installed between the point and the point. The main valve 13 is set to the open state in the normal state. The main valve 13 is also a bidirectional valve like the sub valve 15. A flow meter (B) 14 as a second flow rate detecting unit for detecting the flow rate of the gas flowing through the supply pipe 11 is installed downstream of the second point of the supply pipe 11. This flow meter (B) 14 is 0 to several tens m ³ /
It is composed of a sensor capable of measuring a large flow rate in the range of h.

FIG. 2 shows a micro flowmeter (A) in this device.
16 and the flow meter (B) 14 show the relationship of the measurement range, and the minute flow meter (A) 16 has 0 to 500 liters / h.
The flow meter (B) 14 detects a flow rate of 300 liter / h or more. In the range of 300 to 500 liters / h, it is possible to detect the overlaps. This relationship is the same for all the first to third embodiments.

Returning to FIG. 1 and continuing the description, the main valve 1
3, the flow meter (B) 14, the slave valve 15 and the minute flow meter (A) 16 are each connected to a microcomputer 17 as a control means. Microcomputer 1
No. 7 closes the main valve 13 and opens the slave valve 15 when the flow rate detected by the flow meter (B) 14 is in the minute flow rate mode of less than a predetermined flow rate (for example, 300 liter / h). As a state, the flow of gas is switched from the supply pipe 11 to the side of the branch pipe 12, and then the presence or absence of gas leakage is determined based on the detection result of the micro flowmeter (A) 16, and when it is determined that there is leakage, the sub-valve 15 also In the closed state, the flow path is completely shut off, and when it is determined that there is no leakage, if the flow rate detected by the micro flow meter (A) 16 becomes larger than a predetermined flow rate (for example, 500 liter / h), the main valve 13 Is opened and the child valve 15 is closed to control the flow of gas from the branch pipe 12 to the supply pipe 11 side. That is, the microcomputer 17 has a function as a flow path switching unit together with the main valve 13 and the slave valve 15, and also has a function as a leak detection unit.

The microcomputer 17 is also connected with an alarm notifying section 18 as an alarm notifying means for notifying an abnormal state. The alarm notifying unit 18 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 17 drives the alarm notifying unit 18 to prompt a customer or a service person to recover. Although not shown, the alarm notification unit 18 may also be used as an alarm device attached to the gas meter on the downstream side.

The microcomputer 17 is further connected to a solar cell 19 which serves as a power source for this apparatus. As the power source, a commercial power source, a battery, or the like can be used, but since the main body portion including the microcomputer 17 of this device can be installed on the outer wall surface of the house, it is driven by the solar cell 19 in this case. It is preferable. The solar cell 19 may be used in combination with a battery or a commercial power source.

The microcomputer 17 is connected to a telephone line via a communication controller 30 for controlling switching with a telephone, and further connected via a switch 40 to a host computer 51 installed in an automatic meter reading center 50. When the microcomputer 17 is connected and gas leakage is detected, the fact is notified to the host computer 51.

FIG. 3 is a block diagram showing the configuration of the microcomputer 17 constituting the control unit of the leak detection apparatus 10 and its peripherals. As shown in this figure, the microcomputer 17 includes a CPU (Central Processing Unit) 170, R
OM (Read Only Memory) 171, RAM (Random Access Memory) 172, Clock 1 for clocking
73 and an input / output port 174, which are connected to each other by a bus 175. I / O port 17
4 includes a flow meter (B) 14 and a minute flow meter (A) 16
A valve drive circuit 20 for driving the main valve 13 and the slave valve 15 and a communication circuit 21 for notifying the host computer 51 in the automatic meter reading center 50 that there is a gas leak.
And a notification unit drive circuit 2 for driving the alarm notification unit 18.
2 are connected to each other. In the microcomputer 17, the CPU 170 realizes the function as the leak detection device 10 by executing the program stored in the ROM 171 by using the RAM 172 as a working area.

Next, the leak detection device 1 according to the first embodiment.
The operation of 0 will be described with reference to the flowchart shown in FIG.

First, in the normal state, the main valve 13 is in the open state,
The child valve 15 is in a closed state, and the gas supplied from the main branch pipe (not shown) is supplied to the gas meter (not shown) installed in the house through the supply pipe 11. In this state,
In the leakage detection device 10, the microcomputer 17 monitors the flow rate detected by the flow meter (B) 14 (step S401). Then, when the flow rate of the gas in the supply pipe 1 becomes smaller than a predetermined minute flow rate (for example, 300 liter / h), the minute flow mode is set (step S401;
Y), the main valve 13 is closed and the slave valve 15 is opened (step S402). As a result, the gas flow between the first point and the second point of the supply pipe 11 is switched from the supply pipe 11 to the branch pipe 12 side.

Thereafter, the leak detection device 10 judges the presence / absence of gas leak based on the detection result of the minute flow meter (A) 16 (step S403). Here, for the determination of the presence or absence of leakage, for example, when a flow rate smaller than the igniting flow rate of the gas appliance used (for example, 3 liter / h) is continuously detected for a predetermined time or more, it is determined that there is a gas leak. When it is determined that there is leakage (step S403; Y), the child valve 15 is also closed. As a result, the gas flow path upstream of the gas meter is completely cut off. At the same time, in the leak detection device 10,
Recovery is urged by notifying the host computer 51 of the automatic meter reading center 50 that there is a gas leak through the communication circuit 21 and driving the alarm unit drive circuit 22 to activate the alarm alarm unit 18.

On the other hand, in the leak detection device 10, when it is determined that there is no leak (step S403; N), the flow rate detected by the micro flowmeter (A) 16 is monitored (step S404).
However, when the detected flow rate becomes larger than a predetermined flow rate (for example, 500 liters / h) (Y), the main valve 13 is opened and the child valve 15 is closed to flow all the gas from the branch pipe 12. Switch to the supply pipe 11 side (step S4
05). When the detected flow rate does not reach the predetermined flow rate (for example, 500 liters / h) (step S404; N), the process returns to step S403 after the predetermined waiting time, and the gas leak is determined again. Although the flow rate detected by the micro flow meter (A) 16 is monitored here to determine whether or not the flow rate reaches a predetermined flow rate, the flow rate detected by the flow meter (B) 14 is used for the determination. May be.

As described above, in the leak detecting apparatus 10 of this embodiment, the presence or absence of gas leak can be automatically detected by the control of the microcomputer 17. Therefore,
In addition to the conventional manual inspection work,
Since it is possible to constantly monitor, the safety function is also improved. Moreover, since the occurrence of gas leakage can be automatically notified to the automatic meter reading center 50, it becomes easy to centrally manage a large number of supply pipes 11. Further, in this embodiment, the gas flow is switched to the side of the branch pipe 12 having a small flow path diameter at the time of detection, so that the accuracy of gas leak detection is significantly improved.

FIG. 5 shows the configuration of the leak detection device 100 according to the second embodiment of the present invention. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The leak detection apparatus 100 of this embodiment is applied when the flow rate used by the gas meter on the downstream side is close to zero (that is, the gas appliance on the downstream side is in a state of igniting or less), and the A pressure gauge 101 as a pressure detecting means is installed between the slave valve 15 and the minute flow meter (A) 16. The detection signal of the pressure gauge 101 is supplied to the microcomputer 17, and the microcomputer 17 determines whether or not there is a gas leak based on the pressure detected by the pressure gauge 101. The other structure is similar to that of the first embodiment.

Next, the operation of the leak detection apparatus 100 of this embodiment will be described with reference to the flowchart of FIG.

First, in the normal state, the main valve 13 is in the open state,
The child valve 15 is in a closed state, and the gas supplied from the main branch pipe (not shown) is supplied to the gas meter (not shown) installed in the house through the supply pipe 11. In this state,
In the leak detection device 10, the microcomputer 17 monitors the flow rate detected by the flow meter (B) 14 (step S601). Then, when the gas flow rate in the supply pipe 1 becomes a minute flow rate mode that is less than a predetermined minute flow rate (for example, 300 liter / h) (step S601;
Y), the main valve 13 is closed and the slave valve 15 is opened (step S602). As a result, the gas flow between the first point and the second point of the supply pipe 11 is switched from the supply pipe 11 to the branch pipe 12 side. The process up to this point is the same as in the first embodiment.

In the leak detecting device 101 of this embodiment, next, the supply pipe 1 is received in response to the detection result of the micro flowmeter (A) 16.
The flow rate flowing through 1 is the ignition flow rate (for example, 7 to 40 liters /
It is determined whether it is less than h) (that is, the flow rate is almost zero) (step S603). If it is less than the ignition flow rate (Y), the child valve 604 is closed (step S
604), the branch pipe 12 is also shut off. This allows the child valve 60
4 and the flow path between the gas meter (not shown) are sealed. In this embodiment, in this state, the presence or absence of gas leakage is determined by receiving the detection result of the pressure gauge 101 (step S6).
05). That is, when there is a pressure drop of a predetermined amount or more after the elapse of a certain time, it is determined that there is a gas leak. When it is determined that there is a gas leak (step S60
5) Y), the main valve 13 and the child valve 15 are closed, that is, the gas flow path on the upstream side of the gas meter is kept closed. At the same time, in the leak detection device 10, the host computer 51 of the automatic meter reading center 50 is connected through the communication circuit 21.
To notify that there is a gas leak to the alarm unit drive circuit 2
The recovery is urged by driving 2 to operate the alarm notification unit 18 (step S608). In addition, when the flow rate flowing through the supply pipe 11 is equal to or higher than the ignition flow rate (step S60).
3; N), step S606 after the predetermined waiting time.
Move to.

When it is judged that there is no leakage (step S60
5; N), the detected flow rate of the micro flow meter (A) 16 is monitored (step S606), and the detected flow rate becomes larger than a predetermined flow rate (for example, 500 liter / h) (Y).
Then, the main valve 13 is opened and the child valve 15 is closed to switch all gas flows from the branch pipe 12 to the supply pipe 11 side (step S607), and the process returns to step S601. The detected flow rate is a predetermined flow rate (for example, 500
Liter / h) is not reached (step S606:
In N), the process returns to step S603 after a predetermined waiting time, and it is determined again whether the flow rate flowing through the supply pipe 11 is less than the ignition flow rate.

As described above, the leak detection device 100 of this embodiment is
Also in the above, similarly to the first embodiment, the presence or absence of gas leakage can be automatically detected. Therefore, the conventional manual inspection work becomes unnecessary, and since it is possible to constantly monitor, the safety function is significantly improved. Moreover, since the occurrence of gas leakage can be automatically notified to the automatic meter reading center 50, it becomes easy to centrally manage a large number of supply pipes 11. Further, in the present embodiment, at the time of detection, the gas flow is switched to the side of the branch pipe 12 having a small flow path diameter, and the gas leak is judged based on the detection result of the pressure gauge 101. The gas leak detection accuracy is improved.

FIG. 7 shows the configuration of a leak detection device 1000 according to the third embodiment of the present invention. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The leak detecting apparatus 1000 of this embodiment is the first
In the leak detection device 10 according to the embodiment, the supply pipe 11
The flowmeter (B) 14 installed in the above and the slave valve 13 installed in the branch pipe 12 are removed to simplify the structure.
The valve 13a corresponds to the main valve 13 of the first embodiment. The other structure is similar to that of the first embodiment.

Next, the operation of the leak detection apparatus 1000 of this embodiment will be described with reference to the flow chart shown in FIG.

First, in the normal state, the valve 13a is in the open state, and the gas supplied from the main branch pipe (not shown) is supplied through the supply pipe 11 to a gas meter (not shown) installed in the house.
Is supplied to the side. In this state, the leak detection device 100
At 0, the flow rate detected by the micro flow meter (A) 16 is monitored by the microcomputer 17 (step S801). Then, when the gas flow rate in the supply pipe 1 becomes a minute flow rate mode that is less than a predetermined minute flow rate (for example, 300 liter / h) (step S801; Y), the valve 13
A is closed (step S802). As a result, the gas flow between the first point and the second point of the supply pipe 11 is switched from the supply pipe 11 to the branch pipe 12 side.

After that, in the leak detection device 10, as in the first embodiment, the presence / absence of gas leak is judged based on the detection result of the micro flowmeter (A) 16 (Sstep 803). When it is determined that there is a leak (Y), the fact that there is a gas leak is notified to the host computer 51 of the automatic meter-reading center 50 through the communication circuit 21, and the alarm unit drive circuit 22 is driven to activate the alarm alarm unit 18. Prompt recovery. On the other hand, when it is determined that there is no leakage (step S80
3; N), the detected flow rate of the micro flow meter (A) 16 is monitored (step S804), and the detected flow rate becomes larger than a predetermined flow rate (for example, 500 liters / h) (Y).
Then, the valve 13a is opened to switch the gas flow from the branch pipe 12 to the supply pipe 11 side (step S805). When the detected flow rate does not reach the predetermined flow rate (for example, 500 liters / h) (N), the process returns to step S803 after the predetermined waiting time, and the gas leak is determined again.

As described above, the leak detection device 100 according to the present embodiment.
Even in 0, since it is possible to automatically detect the presence or absence of gas leakage, as in the first embodiment, manual inspection work is not required and the safety function is improved, and more supply pipes 11 are connected. Centralized management becomes easier, and detection accuracy improves. Further, in this embodiment, the flow meter (B) 14 and the child valve 13 in the first embodiment are not necessary, so the structure is simple. In this device, the flow path of the supply pipe 11 cannot be blocked when there is a gas leak, but the microcomputer 17 and the gas meter on the downstream side are electrically connected and the microcomputer 17
If the configuration is such that the shutoff valve inside the gas meter is driven according to the notification from, the gas can be shut off and the safety function is improved.

The present invention has been described above 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 50, the automatic meter reading center 50 side is notified only when a gas leak occurs.
1 enables the bidirectional communication between the microcomputer 1 and the microcomputer 17, and performs a detection start instruction operation and the like by the host computer 5.
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 such as the solar cell 19 can be reduced.

[0050]

As described above, according to the leak detecting device of the present invention, a branch pipe having a flow path diameter smaller than that of the supply pipe is provided along with the supply pipe, and the flow rate of the fluid flowing through the supply pipe is less than a predetermined flow rate. When the micro flow rate mode is set, the fluid flow is switched from the supply pipe to the branch pipe side, and after that, the presence or absence of leakage is detected based on the flow state in the branch pipe. Can be detected. Therefore, it is possible to eliminate the need for manpower for detection, to constantly monitor the presence or absence of leakage, and to improve the detection accuracy, thereby significantly improving the safety.

[Brief description of drawings]

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

FIG. 2 is a diagram for explaining a relationship between detection ranges of two sensors used in the leak detection device of FIG.

3 is a block diagram showing a circuit configuration of a control unit of the leak detection apparatus of FIG. 1 and its peripherals.

FIG. 4 is a flow chart for explaining the operation of the leak detection apparatus of FIG.

FIG. 5 is a block diagram showing a configuration of a leak detection device according to a second exemplary embodiment of the present invention.

6 is a flow chart for explaining the operation of the leak detection apparatus of FIG.

FIG. 7 is a block diagram showing a configuration of a leak detection device according to a third exemplary embodiment of the present invention.

FIG. 8 is a flowchart for explaining the operation of the leak detection device of FIG.

FIG. 9 is a block diagram for explaining the basic configuration of the present invention.

[Explanation of symbols]

 10, 100, 1000 Leak detection device 11 Supply pipe 12 Branch pipe 13 Main valve (second flow path opening / closing means) 13a Valve (flow path opening / closing means) 14 Sub-valve (first flow path opening / closing means) 15 Flow meter ( B) (Second flow rate detection means) 16 Micro flowmeter (A) (First flow rate detection means) 17 Microcomputer (control means) 18 Alarm informing section (alarm informing means) 19 Solar cell

Claims (9)

[Claims] 1. A leak detection device for detecting the presence or absence of leakage of a fluid flowing through a supply pipe having a predetermined flow passage diameter in the supply pipe, the leak detection device having a flow passage diameter smaller than that of the supply pipe. A branch pipe for branching the flow of the fluid from a first point in the middle of the supply pipe, and then guiding the branched flow to a second point downstream of the first point of the supply pipe And when the flow rate of the fluid flowing through the supply pipe is in a minute flow rate mode of less than a predetermined flow rate, the fluid flow between the first point and the second point is changed from the supply pipe to the branch pipe side. And a leak detection unit that detects the presence or absence of a leak based on the flow state in the branch pipe after the flow of the fluid is switched to the branch pipe side by the flow passage switching unit. Characteristic leak detection device. 2. A leak detection device for detecting the presence or absence of leakage of a fluid flowing through a supply pipe having a predetermined flow passage diameter in the supply pipe, the leak detection device having a flow passage diameter smaller than that of the supply pipe. A branch pipe for branching the flow of the fluid from a first point in the middle of the supply pipe, and then guiding the branched flow to a second point downstream of the first point of the supply pipe A first flow path opening / closing means provided in the branch pipe and set to a closed state in a normal state; and a first flow rate detecting means provided in the branch pipe for detecting a flow rate of a fluid flowing through the branch pipe. And a second flow path opening / closing means which is provided between a first point and a second point of the supply pipe and which is set to an open state in a normal state; Second flow rate detecting means provided on the downstream side and detecting the flow rate of the fluid flowing through the supply pipe An alarm notifying means for notifying an abnormal state, and a second flow path opening / closing means in a closed state when the flow rate detected by the second flow rate detecting means is in a minute flow rate mode below a predetermined flow rate. And the flow of the fluid is switched from the supply pipe to the side of the branch pipe by opening the first flow path opening / closing means, and then the presence or absence of the fluid leakage is judged based on the detection result of the first flow rate detecting means. When it is determined that there is leakage, the alarm notification means is activated, while when it is determined that there is no leakage, the first flow rate detection means or the second flow rate detection means.
When the flow rate detected by the flow rate detecting means is larger than a predetermined flow rate, the second flow path opening / closing means is opened and the first flow path opening / closing means is closed, so that a fluid flow from the branch pipe to the supply pipe. A leak detection device comprising: a control unit that controls to switch to a side. 3. The leak detection device according to claim 2, wherein when the control means determines that there is a leak, the first flow path opening / closing means is closed to shut off the flow path. 4. A leak detection device for detecting the presence or absence of leakage of a fluid flowing through a supply pipe having a predetermined flow path diameter in the supply pipe, the leak detection device having a flow path diameter smaller than that of the supply pipe. A branch pipe for branching the flow of the fluid from a first point in the middle of the supply pipe, and then guiding the branched flow to a second point downstream of the first point of the supply pipe A first flow path opening / closing means provided in the branch pipe and set to a closed state in a normal state; and a first flow rate detecting means provided in the branch pipe for detecting a flow rate of a fluid flowing through the branch pipe. And at a position downstream of the first flow path opening / closing means,
A pressure detection unit that detects the pressure of the fluid flowing through the branch pipe, and a second flow path that is provided between the first point and the second point of the supply pipe and is set to an open state in a normal state. An opening / closing means, a second flow rate detecting means provided downstream of the second point of the supply pipe for detecting a flow rate of a fluid flowing through the supply pipe; and an alarm notifying means for notifying an abnormal state, The second flow path opening / closing means is closed and the first flow path opening / closing means is opened when the flow rate detected by the second flow rate detecting means is in a minute flow rate mode in which the flow rate is less than a predetermined flow rate. As a result, the flow of the fluid is switched from the supply pipe to the branch pipe side, and thereafter, when the flow rate detected by the first flow rate detecting means becomes close to zero, the first flow path opening / closing means is closed. In this state, the detection result of the pressure detection means is received. If it is determined that there is a leak, the alarm notification means is activated. On the other hand, if it is determined that there is no leak, the flow rate detected by the first flow rate detection means is larger than a predetermined flow rate. In this case, the leakage detection device further comprises: a control unit that controls the flow of the fluid to be switched to the supply pipe side by opening the second flow path opening / closing unit. 5. A leak detection device for detecting the presence or absence of leakage of a fluid flowing through a supply pipe having a predetermined flow passage diameter in the supply pipe, the leak detection device having a flow passage diameter smaller than that of the supply pipe. A branch pipe for branching the flow of the fluid from a first point in the middle of the supply pipe, and then guiding the branched flow to a second point downstream of the first point of the supply pipe And a flow path opening / closing means provided between the first point and the second point of the supply pipe and set to an open state in a normal state; Flow rate detecting means for detecting the flow rate, and when the flow rate detected by the flow rate detecting means is in a minute flow rate mode less than a predetermined flow rate, the flow path opening / closing means is closed to cause a fluid flow from the supply pipe to the branch pipe Switch to the In response to this, the presence or absence of leakage of fluid is determined, and when it is determined that there is leakage, an alarm is issued, and when it is determined that there is no leakage, the flow rate is detected if the flow rate detected by the flow rate detection means becomes larger than a predetermined flow rate. A leak detection device, comprising: a control unit that controls the fluid flow to be switched to the supply pipe side by opening and closing the opening and closing unit. 6. The leak detection device according to claim 2, wherein a main body including the control means is installed on an outer wall surface of a house, and a solar cell is used as a power source thereof. 7. 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 device according to any one of 1. 8. The 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 shuts off the gas supply by driving the shut-off valve inside the gas meter. The leakage detection device according to claim 7, wherein the leakage detection device is configured as described above. 9. 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. The leak detection device described.