JP5368121B2 - Gas leak detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly detect a fault of a device and gives a call to a processing center or the like, in regard to the system for detecting a minute leak of gas in a gas supply pipe 30. <P>SOLUTION: The gas is made to flow to a master-and-slave type differential pressure regulator 1 from a propane gas cylinder 10 through a main regulator 20. A master regulator 11 of the master-and-slave type differential regulator 1 supplies the gas to the apartment house 40 side from the gas supply pipe 30. A slave regulator 12 is connected to a bypass gas passage 2 continuous to the gas supply pipe 30, bypassing the master regulator 11. A microcomputer gas meter 3 is provided for the bypass gas passage 2. The gas pressure is sampled at a high speed by a pressure sensor of the microcomputer gas meter 3 so as to detect a state of the use of a gas appliance 50. A flow rate of the gas is detected by the flow sensor of the microcomputer gas meter 3. When the gas appliance 50 is in the state of the use and a flow rate can not be detected for a prescribed time, fault alarm processing is performed and the call is given to the processing center. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a gas leakage detection device that is provided in a gas supply facility that supplies gas from a gas supply source such as a gas cylinder to a gas consumption source such as a gas combustion device and that detects a minute leak in a gas supply pipe such as an embedded pipe.

  Conventionally, as this type of apparatus, there are those disclosed in, for example, Japanese Patent Application Laid-Open No. 3-41300 (Patent Document 1) and Japanese Patent Application Laid-Open No. 5-296873 (Patent Document 2). These gas leak detection devices are provided with a bypass flow path that bypasses the parent regulator in a gas supply pipe that supplies gas from a propane gas cylinder to an apartment house and the like. A micrometer having a raised child regulator and a flow rate detecting means for detecting a minute flow rate is provided.

  These configurations are designed so that a micro flow rate can be detected by a microcomputer meter via a slave regulator even when the parent regulator is closed when there is almost no gas consumption at night or at midnight. The minute flow rate is monitored by a microcomputer meter, and when there is a flow rate of 3 liters / hour or more for 30 consecutive days, it is judged that a slight gas leakage has occurred and this is indicated by lighting the lamp. .

JP-A-3-41300 JP-A-5-296873

  In the conventional gas leak detection apparatus, it is possible to detect minute gas leaks on the assumption that the parent adjuster, the slave adjuster, and the microcomputer meter are functioning normally. Even if any of these functions is impaired, accurate detection cannot be performed.

  For example, if the child adjuster breaks down due to foreign matter inside, or if the adjustment pressure changes due to deterioration over time, the differential pressure between the output of the child adjuster and the output of the parent adjuster A certain pressure value (for example, 50 Pa) or more cannot be secured, the flow rate does not flow to the microcomputer meter, and even if a slight leak occurs in the piping, it cannot be detected.

  Therefore, in the past, periodic inspections are performed, but this periodic inspection measures the differential pressure between the output of the child regulator and the output of the parent regulator, and if there is a differential pressure greater than a certain pressure value. It was judged that it was normal.

  However, this regular inspection work required labor for the operator to visit the site, install a pressure gauge, and perform measurement. In addition, when a failure was discovered in the microcomputer meter during regular inspection, there was a possibility that gas had leaked during the period up to that point, and there was doubt about the reliability of the gas leak detection device.

  It is an object of the present invention to provide a gas leakage detection device with a self-diagnosis function so that an abnormality of the device itself can be quickly reported to a center or the like.

The gas leakage detection device according to claim 1 detects the flow rate of the child regulator having a higher regulation pressure than the parent regulator and the flow rate of the bypass gas passage in the bypass gas passage bypassing the parent regulator provided in the gas supply pipe. And a flow rate detection means for detecting a minute gas leak by detecting the presence of a flow rate for a predetermined period of time by the flow rate detection means, and detecting the pressure of the bypass gas flow path. A pressure detection means for outputting a pressure detection signal and a downstream side of the bypass gas flow path based on a pressure vibration frequency and a pressure vibration amplitude of a pressure vibration waveform at the start of gas use of the pressure detection signal from the pressure detection means A determination means for determining a use state of the gas appliance connected to the gas appliance, and a failure alarm process when the determination means determines that the gas appliance is in use and the flow rate detection means does not detect the flow rate. And a fault diagnosis means for the said determination means, a pressure detected by said pressure detecting means and speed sampling, analyzing the pressure oscillation frequency and the pressure oscillation amplitude of the pressure vibration waveform by the pressure data sampled, 10 Hz When a pressure vibration waveform having the above pressure vibration frequency was obtained, and a pressure vibration waveform in which the pressure vibration amplitude exceeded the pressure immediately before the start of gas use or the pressure immediately before the change in the amount of gas used by 0.015 kPa or more. If determines that the governor with gas appliance in use, regardless of the pressure oscillation frequency, pressure oscillation pressure oscillation amplitude not exceeding 0.015kPa than pressure of the pressure and the gas consumption immediately before the change just before the start the gas used When a waveform is obtained, it is determined that the gas appliance without a governor is being used.

  The gas leakage detection device according to claim 2 is the gas leakage detection device according to claim 1, wherein the failure diagnosis unit is determined to be in use of the gas appliance by the determination unit after a predetermined time has elapsed. It is characterized by determining whether the flow rate is detected by the flow rate detection means.

  The fact that the gas flow rate cannot be detected even though the gas appliance is used is highly likely that the slave regulator or the flow rate detection means is out of order. Without waiting for inspection, this failure can be detected quickly and reported by failure alarm processing.

  According to the gas leak detection device of claim 2, in addition to the effect of claim 1, it is possible to accurately determine the flow rate without being affected by the damping vibration of the flow rate immediately after ignition of the gas appliance. The accuracy of detection increases.

It is a principal part block diagram of the gas leak detection apparatus of one Embodiment of this invention. 1 is an external view of a gas supply system to which a gas leakage detection device of an embodiment is applied. It is a principal part flowchart of the control program of the control part in embodiment. It is a flowchart of the timer interruption process of the control part in embodiment. It is a figure which shows an example of the pressure characteristic at the time of the gas use start in the gas appliance with a governor which concerns on embodiment, or a gas usage-amount change. It is a principal part flowchart of the control program of the control part in a reference example .

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a main part of a gas leak detection apparatus according to an embodiment of the present invention, and FIG. 2 is an external view of a gas supply system to which the gas leak detection apparatus according to the embodiment is applied. The gas leak detection apparatus of this embodiment is disposed between a propane gas cylinder 10 that is a gas supply source and an apartment house 40 such as an apartment that is a gas consumption source.

  The propane gas cylinder 10 is connected to the parent-child differential pressure regulator 1 via the original regulator 20, and the original regulator 20 supplies the gas from the propane gas cylinder 10 to a predetermined pressure and supplies it to the parent-child differential pressure regulator 1. To do. The parent-child differential pressure regulator 1 includes a parent regulator 11 and a child regulator 12, and the gas from the original regulator 20 is supplied to the parent regulator 11 and the child regulator 12, respectively. The outlet 11a of the parent regulator 11 is connected to a gas supply pipe 30 that supplies gas to the apartment house 40 side. The outlet 12 a of the child adjuster 12 is connected to the bypass gas flow path 2 that bypasses the parent adjuster 11 and is connected to the gas supply pipe 30. A microcomputer gas meter 3 is provided in the bypass gas passage 2.

The adjustment pressure of the child adjuster 12 is set higher than the adjustment pressure of the parent adjuster 11. For example, when the adjustment pressure of the parent adjuster 11 is set to 280 mmH ₂ O, the adjustment pressure of the child adjuster 12 is set to about 300 mmH ₂ O. As a result, when there is normal gas consumption on the apartment house 40 side, gas is supplied via the parent regulator 11 and the child regulator 12. On the other hand, when there is almost no gas consumption at night or in the middle of the night, the pressure of the gas supply pipe 30 is increased, the parent regulator 11 is closed, and gas flows only to the child regulator 12 and the microcomputer gas meter 3. Thereby, the micro gas flow rate which flows through the bypass gas flow path 2 can be monitored by the microcomputer gas meter 3.

  As shown in FIG. 1, the microcomputer gas meter 3 includes a control unit 31 that constitutes a determination unit and a failure diagnosis unit, a flow rate sensor 32 as a flow rate detection unit, a pressure sensor 33 as a pressure detection unit, an EEPROM 34, a display unit 35, and a communication. The unit 36 is configured to be included. The control unit 31 is configured by a microcomputer having a CPU, a ROM, a RAM, and the like, and performs processing described later when the CPU executes a control program stored in the ROM.

  The flow rate sensor 32 is a detection element for detecting the flow rate of the gas passing through the bypass gas flow path 2, and can accurately integrate a minute flow rate (for example, about 3 liters / hour). When the flow rate of the gas is detected by the flow rate sensor 32 and the gas continues to flow continuously for 30 days, it is determined that there is a slight leak of the gas somewhere in the gas supply pipe 30, and the display unit displays the fact. In addition, the communication unit 36 makes a call to the center.

  The pressure sensor 33 is a known detection element, and the pressure sensor 33 detects the internal pressure of the bypass gas flow path 2 on the downstream side of the child adjuster 12. The pressure sensor 33 monitors the internal pressure of the bypass gas flow path 2 and detects the usage state of the gas appliance 50 in the apartment house 40. Then, a self-diagnosis is performed in accordance with the use state and the flow rate detected by the flow sensor 32. When it is determined that there is a failure, the fact is displayed on the display unit 35 and a call is made to the center by the communication unit 36. Do.

  Here, recent gas appliances include a gas grill, a gas water heater, a gas dishwasher, a gas oven, a gas fan heater, a gas instantaneous water heater, a gas floor heater, a gas heat pump (GHP), etc. A governor as a pressure adjusting means is built in, and the gas pressure is adjusted for each instrument. Many gas stoves (gas tables) do not have a built-in governor.

  FIG. 5 is a diagram illustrating an example of pressure characteristics at the start of gas use or when the amount of gas used changes in a gas appliance with a governor. Due to its structure, the governor causes a pressure fluctuation due to a gas pressure regulating operation instantaneously when the gas flow rate changes, that is, when the gas usage starts or when the gas usage amount changes. This is a damped vibration that converges in about 0.3 to 1 second. This vibration shows the characteristic (pressure waveform) specific to the governor being used. Accordingly, it is possible to quickly sample the pressure with the pressure sensor 33, and to determine in a short time that the gas appliance 50 has started to be used based on the pressure fluctuation waveform at the start of gas use or when the gas usage changes. Become.

  That is, the pressure vibration frequency and pressure vibration amplitude of the pressure waveform are analyzed based on the sampled pressure data to determine whether the gas appliance is used. For example, if a pressure vibration waveform having a frequency of 10 Hz or more is obtained, it can be determined that the gas appliance with a governor is being used. Similarly, if a pressure vibration waveform is obtained in which the vibration amplitude exceeds the pressure immediately before the start of gas use (that is, the original pressure) or the pressure immediately before the gas use amount change more than a predetermined pressure value (0.015 kPa), It can be determined that the gas appliance with governor is in use. Similarly, if there is a pressure vibration waveform in which the pressure vibration amplitude rises to the pressure just before the start of gas use (ie, the original pressure) or the pressure just before the gas usage change, regardless of the frequency, there will be no governor. It can be determined that the gas appliance is in use.

  FIG. 3 is a main part flowchart of a control program of the control unit 31 (microcomputer) in the embodiment, and FIG. 4 is a flowchart of timer interrupt processing of the control unit 31, and the operation will be described based on the same figure. In the following description, a counter for counting the number of days (period) for determination of microleakage is referred to as “microleakage counter”.

  In the timer interrupt process of FIG. 4, it is determined whether or not one day has passed in step S21. If this determination is YES, the process proceeds to step S22. If NO, the process returns to the original routine without doing anything. In step S22, the minute leak counter is counted up, and in step S23, it is determined whether or not the content of the minute leak counter is equal to 30. When the determination is NO, the process returns to the original routine, and when the determination is YES, it is determined that a slight leak has occurred for 30 days without the flow rate becoming zero, and a leakage alarm process is performed in step S24. To return to the original routine.

  In the process of FIG. 3, first, in step S <b> 1, the pressure is measured by the pressure sensor 33 and the flow rate is measured by the flow rate sensor 32. Next, in step S2, it is determined whether the flow rate is 0. If the flow rate is 0, the minute leak counter is cleared and the process proceeds to step S4. If the flow rate is not 0, the process proceeds to step S13. This process is a process that always clears the micro-leakage counter because there is no micro-leakage when there is no flow rate.

  In step S4, it is determined whether or not the measured pressure has become smaller than a measurement start pressure value set in advance for determination. If the pressure is not smaller than the measurement start pressure value, the process proceeds to step S13. If the pressure is smaller, the gas usage has started or the gas usage has changed. High speed sampling of pressure. The predetermined number of data is set so that the number of data necessary for the frequency analysis and the amplitude analysis of the pressure vibration waveform at the start of gas use or when the gas use amount changes is collected.

  Next, in step S6, frequency analysis and amplitude analysis are performed based on the sampled pressure data to determine the usage state of the gas appliance 50 in the apartment house 40. And the use condition of the gas appliance 50 is memorize | stored by step S7, and it progresses to step S8. In the housing complex 40, residents of many households repeat ignition / extinguishing of gas water heaters, gas stoves, gas stoves, and the like. However, it is not necessary to make a detailed determination, such as which resident in which room the gas appliance has ignited, and it is only necessary to grasp the use state in which the gas appliance 50 is lit.

  In step S8, it is determined whether the gas appliance 50 is in use. If it is not in use, the process proceeds to step S13, and if it is in use, in step S9, it is monitored whether a predetermined delay time has elapsed since the start of gas use or the change in gas use amount. The reason for providing this delay time is that immediately after the gas appliance 50 is ignited, a damped vibration waveform is generated for both pressure and flow rate. Because there is. When the delay time elapses, the flow rate is monitored by the flow rate sensor 32 for a predetermined time (for example, 2 to 3 minutes) in step S10. Then, in step S11, it is determined whether or not the state where the flow rate = 0 continues for a certain period of time. If it does not continue for a certain period of time, the process proceeds to step S13. move on. As the failure alarm process, a process of calling the center or the like by the communication unit 36 is performed. In step S13, other processes such as pressure abnormality monitoring are performed, and the process returns to step S1.

  As described above, when the flow rate is 0 even when the gas appliance is in use, that is, when the flow rate cannot be detected, it can be determined that some failure has occurred in the flow rate sensor 32 or the slave adjuster 12, and this failure has occurred. Can be promptly reported.

FIG. 6 is a main part flowchart of a control program of the control unit 31 (microcomputer) in the reference example . In this reference example , the interruption process shown in FIG. 4 is performed for detection of a minute leak and a leak alarm. In this reference example , the usage state of the gas appliance 50 is determined based on a change in pressure detected by the pressure sensor 33, and a failure alarm is given when the gas appliance 50 is regarded as being in use and the flow rate cannot be detected.

  First, in step S <b> 31, the pressure is measured by the pressure sensor 33 and the flow rate is measured by the flow rate sensor 32. Next, in step S32, it is determined whether the flow rate is 0. If the flow rate is 0, the minute leak counter is cleared and the process proceeds to step S34. If the flow rate is not 0, the process proceeds to step S40. This process is a process that always clears the micro-leakage counter because there is no micro-leakage when there is no flow rate.

In step S34, it stores the pressure P ₀ measured, predetermined value the pressure from P ₀ during the predetermined time at step S35, S36 (e.g., 0.05 kPa) for monitoring a decrease or rapidly. Note that steps S31 to S36 and S40 are substantially repeated even if there is no decrease during the monitoring for a certain period of time. If the pressure rapidly decreases from P ₀ by a predetermined value or more, the flow rate is monitored by the flow rate sensor 32 for a certain time (for example, 2 to 3 minutes) in step S37. In step S38, it is determined whether or not the flow rate is 0. If the flow rate is not 0 (if there is a flow rate), the process proceeds to step S40. If the flow rate is 0 (if there is no flow rate), a failure occurs in step S25. An alarm process is performed, and the process proceeds to step S40. As the failure alarm process, a process of calling the center or the like by the communication unit 36 is performed. In step S40, other processes such as pressure abnormality monitoring are performed, and the process returns to step S31.

In an apartment house, for example, when all the residents in the middle of the night are not using any gas, the flow rate is 0 and the block is closed, and the gas pressure in the bypass gas passage 2 (pressure sensor 33) is, for example, 3.10 kPa. . When one unit such as a gas water heater or a gas stove is used, the gas pressure in the bypass gas passage 2 is, for example, 3.00 kPa, which is reduced by about 0.10 kPa.

  Further, when the child adjuster 12 is normal, if the pressure suddenly drops by a predetermined value (for example, 0.05 kPa) or more, the flow rate should be detected at least for one gas appliance, and the flow rate = 0. Must not. On the other hand, when the child adjuster 12 deteriorates over time, the differential pressure in the child adjuster 12 gradually decreases. For example, even if there is a flow rate on the stove with low heat, the flow rate cannot be detected. Therefore, such a failure of the child adjuster 12 can be detected by the above processing.

DESCRIPTION OF SYMBOLS 1 Parent-child type differential pressure regulator 11 Parent regulator 12 Child regulator 2 Bypass gas flow path 3 Microcomputer gas meter 31 Control part (discriminating means and failure diagnosis means)
32 Flow rate sensor (flow rate detection means)
33 Pressure sensor (pressure detection means)
34 EEPROM
35 Display unit 36 Communication unit 10 Propane gas cylinder 20 Original regulator 30 Gas supply pipe 40 Apartment house 50 Gas appliance

Claims (2)

A bypass gas passage bypassing the parent regulator provided in the gas supply pipe is provided with a child regulator having a higher regulation pressure than the parent regulator and a flow rate detecting means for sensing the flow rate of the bypass gas passage, and the flow rate detection In the gas leak detection device that detects a minute gas leak by detecting that there is a flow rate for a predetermined period by means,
Pressure detecting means for detecting the pressure of the bypass gas flow path and outputting a pressure detection signal;
Based on the pressure vibration frequency and the pressure vibration amplitude of the pressure vibration waveform at the start of gas use of the pressure detection signal from the pressure detection means, the use state of the gas appliance connected to the downstream side of the bypass gas flow path is determined. Discrimination means;
A failure diagnosis means for performing a failure alarm process when it is determined that the gas appliance is in use by the determination means and no flow rate is detected by the flow rate detection means;
With
The discrimination means samples the pressure detected by the pressure detection means at a high speed, analyzes the pressure vibration frequency and pressure vibration amplitude of the pressure vibration waveform based on the sampled pressure data,
When a pressure vibration waveform having a pressure vibration frequency of 10 Hz or more is obtained, and a pressure vibration waveform in which the pressure vibration amplitude exceeds 0.015 kPa or more than the pressure immediately before the start of gas use or the pressure immediately before the change of gas usage is obtained. If it is determined that the gas appliance with governor is in use,
Regardless pressure oscillation frequency, if the pressure vibration waveform whose pressure oscillation amplitude not exceeding 0.015kPa than pressure of the pressure and the gas consumption immediately before the change just before the start the gas used was obtained, no governor gas appliance used A gas leak detection device characterized by being determined as being inside.   2. The failure diagnosis unit determines whether or not a flow rate is detected by the flow rate detection unit after a predetermined time has elapsed after the determination unit determines that the gas appliance is in use. The gas leak detection device described in 1.

Images