JP4083367B2 - Gas security device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas security device that measures the flow rate of a gas flowing through a gas flow channel and shuts off the gas flow channel when an abnormal flow rate is detected, thereby ensuring safety in use of the gas.
[0002]
[Prior art]
If a gas meter that measures the amount of gas used detects a large flow rate or a flow rate that is too long to be normal, it is judged abnormal and the gas flow path is shut off. A gas safety device with a built-in gas safety device that ensures safety in use is in widespread use.
[0003]
As a method for measuring the gas flow rate in this gas security device, an ultrasonic gas flow meter is known in which an ultrasonic sensor is operated at predetermined time intervals and the flow rate is measured from the integration of instantaneous flow rates.
[0004]
FIG. 7 shows a conventional configuration of an ultrasonic gas flow meter and a gas security device using the ultrasonic gas flow meter. When measuring the amount of gas used, the control signal is output from the control circuit 31 to the ultrasonic sensor drive circuit 32 at a predetermined interval, so that the ultrasonic sensor drive circuit 32 receives the ultrasonic sensor based on the drive signal corresponding to the control signal. 33 is operated and the instantaneous flow rate flowing through the gas flow path 34 is measured. The control circuit 31 calculates the integrated gas usage based on the instantaneous flow rate data returned from the ultrasonic sensor drive circuit 32. Further, the control circuit 31 determines whether or not the calculated integrated gas usage amount is abnormal, and when it is determined as abnormal, outputs a cutoff signal to the cutoff valve drive circuit 35 to operate the cutoff valve drive circuit 35. As a result, the shutoff valve 36 is closed to shut off the gas flow path 34. In such a gas security device, the battery 37 is used as a power source because the installation location is outdoors and the convenience of installation.
[0005]
[Problems to be solved by the invention]
However, in the gas safety device having the above-described conventional configuration, a GHP (Gas Heat Pump) is installed on the upstream side of the piping of the gas flow path 34, and when this is used, the pressure of the gas supplied to the gas security device varies. As a result, since the gas flow rate fluctuates, in the ultrasonic sensor 33 that measures the gas flow rate based on the detection of the gas flow velocity, when the pressure fluctuation period and the measurement period of the ultrasonic sensor 33 match, There was a problem that accurate measurement results could not be obtained.
[0006]
Thus, when a device that causes pulsation in gas pressure, such as GHP, is installed, if an accurate flow rate cannot be measured, the function as a gas security device will not be exhibited accurately, and the gas It will not be possible to secure safety with the security device.
[0007]
The purpose of the present invention is to prevent the flow measurement from becoming inaccurate when a gas appliance with pressure fluctuation is installed on the upstream side of the gas flow path where the gas safety device is installed. It is an object of the present invention to provide a gas safety device that secures gas use by shutting off gas.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a first invention of the present application includes an ultrasonic sensor that detects an instantaneous flow rate of a gas flowing in a gas flow path, an ultrasonic sensor driving circuit that drives the ultrasonic sensor, and an ultrasonic sensor driving method. Outputs a control signal for measuring the flow rate to the circuit, calculates the instantaneous flow rate for each predetermined time interval from the instantaneous flow rate detection data input from the ultrasonic sensor drive circuit, and shuts off signal when an abnormality is detected in the gas flow rate A shutoff valve that shuts off the gas flow path, a shutoff valve drive circuit that drives the shutoff valve by a shutoff signal output from the control circuit, and a predetermined time interval that is calculated by the control circuit the variation range of fluctuation of the instantaneous flow rate were predetermined in unit time for each number of times exceeding vertically measured, compared to a predetermined number of times, it is installed a pressure fluctuation generated gas appliances in the gas passage Or a pressure fluctuation occurrence determination means for determining whether that, which when exceeded the number of times reaches a predetermined beyond the variation range, and to determine that the pressure fluctuations generated gas appliances are installed It is.
[0009]
According to the above configuration, when the number of times the measured gas flow rate exceeds the predetermined fluctuation range during a predetermined unit time exceeds the predetermined number of times, the pressure fluctuation occurrence determination means is the gas flow path. It can be determined that a pressure fluctuation generating gas appliance such as GHP is installed in Therefore, it is possible to know that the gas flow measurement and the safety operation for detecting the abnormality based on this and shutting off the gas flow path are not performed accurately, and the gas safety device is configured without knowing this. Unstable operation that occurs in some cases can be avoided.
[0010]
The second invention of the present application is an ultrasonic sensor that detects an instantaneous flow rate of a gas flowing in a gas flow path, an ultrasonic sensor drive circuit that drives the ultrasonic sensor at a predetermined drive interval, and an ultrasonic sensor drive Outputs a control signal for measuring the flow rate to the circuit, calculates the instantaneous flow rate for each predetermined time interval from the instantaneous flow rate detection data input from the ultrasonic sensor drive circuit, and shuts off signal when an abnormality is detected in the gas flow rate A shutoff valve that shuts off the gas flow path, a shutoff valve drive circuit that drives the shutoff valve by a shutoff signal output from the control circuit, and a predetermined time interval that is calculated by the control circuit variation of the instantaneous flow rate measuring the number of times exceeds a predetermined fluctuation range in unit time at the top and bottom of each, as compared to a predetermined number of times, has been installed a pressure fluctuation generated gas appliances in the gas passage And pressure fluctuation occurrence determination means for determining whether or not the number of times that the a drive interval changing means for randomly changing the output interval of the control signal to the ultrasonic sensor driving circuit, the number of times that exceeds the variation range is predetermined When the value exceeds the value, the drive interval of the ultrasonic sensor is randomly changed.
[0011]
According to the above configuration, when the number of times the measured gas flow rate exceeds the predetermined fluctuation range during a predetermined unit time exceeds the predetermined number of times, the pressure fluctuation occurrence determination means It can be determined that a pressure fluctuation generating gas appliance such as GHP is installed on the road, and if the driving interval of the ultrasonic sensor is randomly changed by the driving interval variable means, the cycle of the pressure fluctuation and the ultrasonic sensor The drive interval does not coincide with each other, and it is possible to prevent troubles in measuring the gas flow rate due to pressure fluctuation. In addition, an operation of detecting an abnormality based on the measurement of the gas flow rate and shutting off the gas flow path can be performed accurately, and a gas safety device that can perform a stable safety operation even when there is a pressure fluctuation can be provided.
[0012]
In the above configuration, there is provided a flow rate averaged cutoff determining means for obtaining an average flow rate of a predetermined number of instantaneous flow rates measured at the drive interval changed by the drive interval variable means, and the average flow rate is equal to or higher than a preset flow rate. and time, when the so that to output a shut-off signal to the shut-off valve driving circuit, without causing an error in the detection of abnormal flow due to pressure fluctuations, the gas flow path to determine accurately the abnormal flow rate by accurate flow detection A gas safety device to be shut off can be configured.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
[0014]
First, the gas safety device according to the first embodiment will be described with reference to FIGS. 1 and 2.
[0015]
In FIG. 1, the gas flow path 4 is provided with a shutoff valve 6 and an ultrasonic sensor 3 from the upstream side. The ultrasonic sensor 3 transmits and receives ultrasonic waves in an oblique direction with respect to the gas flow path 4, so that the ultrasonic propagation time differs depending on the flow velocity in the gas flow direction and the direction opposite to the gas flow direction. Is used to detect the instantaneous flow rate of the gas flowing through the gas flow path 4, and an ultrasonic wave is transmitted and received by a drive signal output from the ultrasonic sensor drive circuit 2 to perform a detection operation. The control circuit 1 outputs a control signal to the ultrasonic sensor drive circuit 2 at a predetermined time interval, and the ultrasonic sensor drive circuit 2 outputs a drive signal to the ultrasonic sensor 3 in response to the input of the control signal. Since the instantaneous flow rate detected by the ultrasonic sensor 3 is input from the ultrasonic sensor drive circuit 2 to the control circuit 1, the control circuit 1 detects the gas flowing through the gas flow path 4 based on the instantaneous flow rate obtained at predetermined time intervals. The flow rate is calculated.
[0016]
The control circuit 1 outputs a shut-off signal to the shut-off valve drive circuit 5 when a large amount of flow rate is detected or when an abnormality occurs such that a flow rate over a long period of time that cannot be normal is detected. The shut-off valve drive circuit 5 operates in response to the input of a shut-off signal, and operates the shut-off valve 6 to shut off the gas flow path 4 to stop the supply of gas and cope with abnormalities to ensure the safety of gas use.
[0017]
In a gas safety device that measures the gas flow rate using such an ultrasonic sensor 3 and shuts off the gas flow path 4 when an abnormality is detected, an GHP (pressure fluctuation generating gas appliance) is disposed upstream of the gas flow path 4. ), When a gas appliance that causes fluctuations in the pressure of the gas flowing through the gas flow path 4 is installed, flow velocity changes due to pressure fluctuations, which hinders detection of the gas flow rate by the ultrasonic sensor 3. Will be. Therefore, detecting whether or not a gas appliance that causes pressure fluctuations such as GHP is installed in the gas flow path 4 detects an abnormality based on the measurement of the gas flow rate simultaneously with the accurate measurement of the gas flow rate. This is an important requirement for accurately operating the gas security function of blocking the gas flow path 4. GHP determination means (pressure fluctuation occurrence determination means) 8 is provided to detect whether or not a gas appliance that causes this pressure fluctuation is installed.
[0018]
When a GHP is installed on the upstream side of the gas flow path 4, if the GHP is used, the flow rate changes due to pressure fluctuations. Therefore, as shown in FIG. 2, the gas flow rate measured by the control circuit 1 Is a value linked to pressure fluctuation. The GHP determination means 8 measures the number n of times when the fluctuation of the flow rate value exceeds the preset fluctuation range M in the unit time t up and down, and the number n is compared with the preset number N, and n ≧ N If it is, it is determined that there is GHP, and if n ≦ N, it is determined that there is no GHP.
[0019]
With the above configuration, it is possible to detect whether or not the GHP is installed, it is possible to detect in advance a state in which the gas flow rate is not accurately measured due to pressure fluctuations, and the gas flow rate that is the basis for abnormality determination is not satisfactory. Since it is accurate, it is possible to detect a state in which the function as the gas security device is not normally performed and to take a countermeasure. Next, a gas security device having a countermeasure configuration for reducing the influence of the pressure fluctuation and performing accurate gas flow rate measurement and accurate abnormality detection operation will be described as a second embodiment.
[0020]
FIG. 3 shows the configuration of the gas security device according to the second embodiment. Elements common to the configuration of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0021]
In FIG. 3, when the GHP determination unit 8 determines that GHP is present, a determination signal is input from the GHP determination unit 8 to the control circuit 1. At this time, the control circuit 1 operates the drive interval varying means 9 to randomly change the output interval of the control signal to the ultrasonic sensor drive circuit 2. The drive interval variable means 9 outputs the control signal output from the control circuit 1 to the ultrasonic sensor drive circuit 2 as it is while the GHP determination means 8 determines that there is no GHP, and the GHP determination means 8 indicates that there is GHP. When the determination signal is input to the control circuit 1, the operation is performed under the control of the control circuit 1. The control signal output from the control circuit 1 at a constant interval is changed to a random output interval to change the ultrasonic sensor driving circuit 2. To enter.
[0022]
As shown in FIG. 4, in the state where the GHP determination means 8 determines that there is GHP, the gas flow rate changes in conjunction with the pressure fluctuation. If the period of this pressure fluctuation coincides with the output period of the control signal, the measured gas flow rate becomes an inaccurate value. Therefore, when the output interval of the control signal is randomly changed by the drive interval varying means 9 as shown in the figure, the flow rate detection value by the ultrasonic sensor 3 does not coincide with the pressure change, and the flow rate fluctuation value is large or small. Since it is detected at a point, it can be averaged to measure an accurate flow rate that is not affected by pressure fluctuations.
[0023]
Next, a gas security device according to a third embodiment will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the element which is common in the structure of previous embodiment, and the description is abbreviate | omitted.
[0024]
In FIG. 5, when the GHP determination unit 8 determines that there is GHP, a determination signal is input from the GHP determination unit 8 to the control circuit 1. At this time, the control circuit 1 operates the drive interval varying means 9 to randomly change the output interval of the control signal to the ultrasonic sensor drive circuit 2. The drive interval variable means 9 outputs the control signal output from the control circuit 1 to the ultrasonic sensor drive circuit 2 as it is while the GHP determination means 8 determines that there is no GHP, and the GHP determination means 8 indicates that there is GHP. When the determination signal is input to the control circuit 1, the operation is performed under the control of the control circuit 1. The control signal output from the control circuit 1 at a constant interval is changed to a random output interval to change the ultrasonic sensor driving circuit 2. To enter. If the output interval of the control signal is randomly changed by the drive interval varying means 9, the flow rate detection value by the ultrasonic sensor 3 does not coincide with the pressure change, and the flow rate fluctuation value is detected at a large point and a small point. By averaging this, an accurate flow rate that is not affected by pressure fluctuations can be measured.
[0025]
Since the average flow rate is calculated by the cutoff judgment means 10 after the flow rate averaging from the measured flow rate value and the average flow rate value exceeds a preset flow rate value, a cutoff signal is output to the cutoff valve drive circuit 5. The valve drive circuit 5 operates the shutoff valve 6 to shut off the gas flow path 4.
[0026]
When GHP is installed on the upstream side of the gas flow path 4, the shutoff valve 6 is operated at the flow rate value of the peak value (A) of the flow rate fluctuation in the conventional technique, and the actual flow rate value is the average flow rate. Although it is erroneously determined to be equal to the value and erroneous shut-off has been performed, in order to determine whether or not the average flow value exceeds a preset flow value by the shut-off determination means 10 after flow averaging, The erroneous operation of the shutoff valve 6 is eliminated. Therefore, the gas flow path 4 is blocked by accurate abnormality detection, and a highly reliable gas security device can be provided.
[0027]
【The invention's effect】
As described above, according to the present invention, it is possible to detect the installation of a gas appliance that generates pressure fluctuations that hinder measurement of gas flow rate using an ultrasonic sensor. When it is detected that there is a gas appliance that generates this pressure fluctuation, an accurate gas flow rate is provided by a drive interval variable means that randomly changes the drive interval of the ultrasonic sensor so as not to affect the measurement of the gas flow rate due to the pressure fluctuation. Can be measured. In addition, an excessive gas flow rate is accurately detected by measuring the gas flow rate, and a highly reliable gas shutoff device can be configured.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a gas security device according to a first embodiment.
FIG. 2 is a graph illustrating detection of installation of a pressure fluctuation generating gas appliance.
FIG. 3 is a block diagram showing a configuration of a gas security device according to a second embodiment.
FIG. 4 is a graph for explaining changes in the driving interval of the ultrasonic sensor corresponding to pressure fluctuations.
FIG. 5 is a block diagram showing a configuration of a gas security device according to a third embodiment.
FIG. 6 is a graph for explaining setting of a flow rate for operating a shut-off valve.
FIG. 7 is a block diagram showing a configuration of a gas safety device having a conventional configuration.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Control circuit 2 Ultrasonic sensor drive circuit 3 Ultrasonic sensor 4 Gas flow path 5 Shut-off valve drive circuit 6 Shut-off valve 8 GHP determination means (pressure fluctuation generation determination means)
9 Drive interval variable means 10 Flow rate averaged cutoff judgment means

Claims (3)

An ultrasonic sensor for detecting the instantaneous flow rate of the gas flowing in the gas flow path, an ultrasonic sensor driving circuit for driving the ultrasonic sensor, and a control signal for measuring the flow rate is output to the ultrasonic sensor driving circuit to output an ultrasonic signal. The instantaneous flow rate is calculated every predetermined time interval from the instantaneous flow rate detection data input from the sonic sensor drive circuit, and a control circuit that outputs a shut-off signal when an abnormality is detected in the gas flow rate, and the gas flow path are shut off. The shutoff valve, the shutoff valve drive circuit for driving the shutoff valve by the shutoff signal output from the control circuit, and the fluctuation of the instantaneous flow rate at predetermined time intervals calculated by the control circuit are determined in advance in unit time. the variation range is measured the number of times exceeding vertically, as compared to a predetermined number of times, the pressure fluctuation occurrence determination means for determining whether the pressure fluctuations generated gas appliances in the gas flow path is provided Comprising, if the result exceeds the number of the number of times that exceeds the variation range predetermined determines gas safety device and a pressure fluctuation generated gas appliances are installed. An ultrasonic sensor for detecting the instantaneous flow rate of the gas flowing in the gas flow path, an ultrasonic sensor driving circuit for driving the ultrasonic sensor at a predetermined driving interval, and a control signal for measuring the flow rate in the ultrasonic sensor driving circuit And a control circuit for calculating an instantaneous flow rate at predetermined time intervals from instantaneous flow rate detection data input from an ultrasonic sensor driving circuit and outputting a cut-off signal when an abnormality is detected in the gas flow rate, and the gas A change in instantaneous flow rate at predetermined time intervals calculated by the control circuit is a unit time, a cutoff valve that shuts off the flow path, a cutoff valve drive circuit that drives the cutoff valve by a cutoff signal output from the control circuit the predetermined fluctuation range in the number of times exceeding vertically measured, compared to a predetermined number of times, varying the pressure determines whether the pressure fluctuations generated gas appliances in the gas flow path is provided When it exceeds the occurrence determination unit, wherein a drive interval changing means for randomly changing the output interval of the control signal to the ultrasonic sensor driving circuit, the number of times reaches a predetermined exceeding the fluctuation range, the ultrasonic A gas security device characterized by randomly changing the driving interval of a sensor . A flow rate averaging cutoff judgment means for obtaining an average flow rate of a predetermined number of instantaneous flow rates measured at the drive interval changed by the drive interval variable means is provided, and the cutoff is performed when the average flow rate is equal to or higher than a preset flow rate. gas safety device 請 Motomeko 2 wherein you output a blocking signal to the valve drive circuit.

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