JP2001296162A - Gas safety device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas safety device for not causing an erroneous operation, when measuring flow rate according to pressure change by sensing the installa tion of a gas implement for bringing about the pressure change such as a GHP or the upstream side from the device. SOLUTION: The gas flow rate of a gas channel 4 is measured from an instantaneous flow rate, sensed by an ultrasonic sensor 3 under the control of an ultrasonic sensor drive circuit 2 by a control circuit 1. A fault occurs in the measurement of the sensor 3, when the gas implement for bringing about the pressure change, such as GHP is installed at the upstream side from the channel 4. Accordingly, when times which are set beforehand during a unit time and the change exceeding a preset change range are detected during the unit time by a GHP-deciding means 8, it is decided that the GHP has been installed, and then it is controlled to make the driving interval of the sensor 3 changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas safety device which measures the flow rate of a gas flowing through a gas flow path and shuts off the gas flow path when an abnormal flow rate is detected, thereby ensuring safety in gas use. It is about.

[0002]

2. Description of the Related Art Gas meters for measuring the amount of gas used
If a large amount of flow is detected, or if a flow over a long period of time is detected that is not normally possible, it is determined to be abnormal and the gas flow path is shut off to ensure gas use safety. Devices with built-in devices have become widespread.

[0003] As a gas flow measuring method in this gas safety device, there is known an ultrasonic gas flow meter which operates an ultrasonic sensor at predetermined time intervals and measures the flow rate from the integration of instantaneous flow rates.

FIG. 7 shows a conventional configuration of an ultrasonic gas flow meter and a gas safety device using the same. When measuring the gas consumption, the control signal is output from the control circuit 31 to the ultrasonic sensor drive circuit 32 at predetermined intervals, so that the ultrasonic sensor drive circuit 32 uses the ultrasonic sensor according to the drive signal corresponding to the control signal. 33 to operate the gas passage 3
4 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. Also, the control circuit 31
Determines whether the calculated integrated gas usage is abnormal,
If it is determined that an abnormality has occurred, a shutoff signal is output to the shutoff valve drive circuit 35, and the shutoff valve 3 is operated by the shutoff valve drive circuit 35.
6 is closed to shut off the gas flow path 34. The battery 37 is used as a power source in such a gas safety device because the installation location is outdoors and the installation is convenient.

[0005]

However, in the gas safety device having the above-mentioned conventional configuration, a GHP (Gas Heat Pump) is installed on the upstream side of the pipe of the gas flow path 34. Since the pressure of the supplied gas fluctuates, and as a result, the flow velocity of the gas fluctuates, in the ultrasonic sensor 33 that measures the gas flow rate based on the detection of the gas flow velocity, the pressure fluctuation cycle and the measurement cycle of the ultrasonic sensor 33 are measured. When there is a problem, there is a problem that an accurate measurement result cannot be obtained.

[0006] When a device such as GHP that causes a pulsation in the gas pressure is installed, if the accurate flow rate cannot be measured, the function as a gas safety device cannot be exhibited accurately. As a result, the safety of the gas safety device cannot be ensured.

An object of the present invention is to prevent inaccurate flow measurement when a gas appliance with a pressure fluctuation is installed upstream of a gas flow path in which a gas safety device is installed. Another object of the present invention is to provide a gas safety device which ensures the safety of gas use by accurate gas shutoff.

[0008]

According to a first aspect of the present invention, there is provided an ultrasonic sensor for detecting an instantaneous flow rate of a gas flowing in a gas flow path, and an ultrasonic sensor for driving the ultrasonic sensor. The control circuit outputs a control signal for flow rate measurement to the drive circuit and the ultrasonic sensor drive circuit to calculate the gas flow rate from the instantaneous flow rate detection data input from the ultrasonic sensor drive circuit and detect an abnormality in the gas flow rate. A control circuit that outputs a shut-off signal when shut off, a shut-off valve that shuts off the gas flow path, a shut-off valve driving circuit that drives the shut-off valve according to the shut-off signal output from the control circuit, and the gas flow rate is predetermined. If the number of times exceeding a predetermined fluctuation range during a given unit time exceeds a predetermined number, it is determined that a pressure fluctuation generating gas appliance is installed in the gas flow path. Characterized by comprising a constant section.

According to the above configuration, when the number of times that the measured gas flow rate exceeds the predetermined fluctuation range during the predetermined unit time exceeds the predetermined number, the pressure fluctuation occurrence determination means is provided. It can be determined that a pressure fluctuation generating gas appliance such as GHP is installed in the gas flow path. Therefore, it is possible to know that the security operation for measuring the gas flow rate and detecting an abnormality based on the gas flow rate and shutting off the gas flow path is not accurately performed, and the gas safety device is configured without knowing this. Unstable operation that occurs in the case can be avoided.

The second invention of the present application is directed to an ultrasonic sensor for detecting an instantaneous flow rate of gas flowing in a gas flow path, an ultrasonic sensor driving circuit for driving the ultrasonic sensor at a predetermined drive interval, Output a control signal for flow rate measurement to the ultrasonic sensor drive circuit and calculate the gas flow rate from the instantaneous flow rate detection data input from the ultrasonic sensor drive circuit,
A control circuit that outputs a shut-off signal when an abnormality is detected in the gas flow rate, a shut-off valve that shuts off the gas flow path, and a shut-off valve driving circuit that drives the shut-off valve according to the shut-off signal output from the control circuit. If the number of times the gas flow rate exceeds a predetermined fluctuation range during a predetermined unit time exceeds a predetermined number, the pressure fluctuation generating gas appliance is installed in the gas flow path. Pressure fluctuation occurrence determining means for determining, and a drive interval variable means for randomly changing a drive interval of the ultrasonic sensor when it is determined that the pressure fluctuation generating gas appliance is installed by the pressure fluctuation occurrence determining means. It is characterized by becoming.

According to the above arrangement, when the number of times that the measured gas flow rate exceeds the predetermined fluctuation range during the predetermined unit time exceeds the predetermined number, the pressure fluctuation occurrence determining means Can be determined that a pressure fluctuation generating gas appliance such as GHP is installed in the gas flow path,
If the drive interval of the ultrasonic sensor is randomly changed by the drive interval variable means, the cycle of the pressure fluctuation does not coincide with the drive interval of the ultrasonic sensor, which may hinder the measurement of the gas flow rate due to the pressure fluctuation. Can be prevented. In addition, an operation of shutting off the gas flow path by detecting an abnormality based on the measurement of the gas flow rate is also accurately performed, and a gas safety device that performs a stable security operation even when there is a pressure fluctuation can be provided.

In the above-mentioned configuration, the flow rate averaging shut-off determination means for shutting off the gas flow path by the shut-off valve when the average value of the measured flow rate for a predetermined number of times becomes a preset flow rate abnormality is provided. It is possible to configure a gas safety device that accurately determines an abnormal flow rate by accurate flow rate detection and shuts off a gas flow path without causing an error in detection of an abnormal flow rate due to fluctuation.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
The embodiment described below is an example embodying the present invention, and does not limit the technical scope of the present invention.

First, a gas safety device according to a first embodiment will be described with reference to FIGS.

In FIG. 1, a shutoff valve 6 and an ultrasonic sensor 3 are arranged in the gas flow path 4 from the upstream side. The ultrasonic sensor 3 transmits and receives ultrasonic waves obliquely to the gas flow path 4, so that the propagation time of the ultrasonic waves differs depending on the flow velocity in the gas flow direction and in the direction opposite to the gas flow direction. Is used to detect the instantaneous flow rate of gas flowing through the gas flow path 4, and transmit ultrasonic waves by a drive signal output from the ultrasonic sensor drive circuit 2.
Receives and performs detection operation. The control circuit 1 outputs a control signal to the ultrasonic sensor driving circuit 2 at predetermined time intervals, and the ultrasonic sensor driving circuit 2 outputs a driving 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 determines whether the gas flowing through the gas flow path 4 is based on the instantaneous flow rate obtained at predetermined time intervals. Is calculated.

The control circuit 1 outputs a shut-off signal to the shut-off valve driving circuit 5 when a large amount of flow is detected or an abnormal condition such as an unusually long flow is detected. The shut-off valve drive circuit 5 operates in response to the input of a shut-off signal, operates the shut-off valve 6, shuts off the gas flow path 4, stops the gas supply, and copes with the abnormality to ensure safe use of gas.

In a gas safety device that measures a gas flow rate using such an ultrasonic sensor 3 and shuts off the gas flow path 4 when an abnormality is detected, a GHP (pressure fluctuation) is provided upstream of the gas flow path 4. (E.g., a gas generating device) that causes a change in the pressure of the gas flowing through the gas flow path 4 when the gas flow rate changes due to the pressure fluctuation. It will cause trouble. Therefore, it is possible to accurately detect whether or not a gas appliance that causes pressure fluctuation such as GHP is installed in the gas flow path 4 at the same time as accurately measuring the gas flow rate, and to detect an abnormality based on the gas flow rate measurement. This is an important requirement for accurately operating the gas security function of blocking the gas flow path 4. GHP determining means (pressure fluctuation occurrence determining means) 8 is provided to detect whether or not a gas appliance that causes the pressure fluctuation is installed.

When a GHP is installed on the upstream side of the gas flow path 4, if the GHP is used, a change in the flow velocity occurs due to a pressure change. Therefore, as shown in FIG. The gas flow rate becomes a value linked to the pressure fluctuation. The GHP determining means 8 measures the number n of times when the fluctuation of the flow rate value exceeds the predetermined fluctuation range M during the unit time t, and compares the number n with the predetermined number N.
When n ≧ N, it is determined that GHP exists, and when n ≦ N, it is determined that GHP does not exist.

According to the above configuration, it is possible to detect whether or not the GHP is installed, to detect a state where the gas flow rate is not accurately measured due to the pressure fluctuation, and to detect the gas as a reference for abnormality determination. Since the flow rate is inaccurate, it is possible to detect a state in which the function as the gas safety device is not normally performed, and to perform a corresponding measure. Next, a gas safety device having a countermeasure for reducing the influence of the pressure fluctuation and accurately measuring the gas flow rate and performing an accurate abnormality detection operation will be described as a second embodiment.

FIG. 3 shows the configuration of a gas safety device according to the second embodiment. Elements common to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. .

In FIG. 3, when the GHP determining means 8 determines that GHP is present, a determination signal is input from the GHP determining means 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 changing means 9 determines whether the GHP
While it is determined that there is no HP, the control signal output from the control circuit 1 is output to the ultrasonic sensor drive circuit 2 as it is, and the GHP determining means 8 determines that GHP is present,
When the determination signal is input to the control circuit 1, the operation is performed under the control of the control circuit 1, and the control signal output from the control circuit 1 at a constant interval is changed to a random output interval and input to the ultrasonic sensor drive circuit 2. .

As shown in FIG. 4, when the GHP determining means 8 determines that GHP is present, the gas flow rate changes in conjunction with the pressure fluctuation. If the cycle of the pressure fluctuation coincides with the output cycle of the control signal, the measured gas flow rate will be an incorrect 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 timing of the flow rate detection by the ultrasonic sensor 3 does not coincide with the pressure fluctuation, and the point of the large flow rate Since it is detected at a point, an accurate flow rate which is not affected by the pressure fluctuation can be measured by averaging this.

Next, a gas safety device according to a third embodiment will be described with reference to FIGS. Note that the same reference numerals are given to the elements common to the configuration of the previous embodiment,
The description is omitted.

In FIG. 5, when the GHP determining means 8 determines that GHP is present, a determination signal is input from the GHP determining means 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 changing means 9 determines whether the GHP
While it is determined that there is no HP, the control signal output from the control circuit 1 is output to the ultrasonic sensor drive circuit 2 as it is, and the GHP determining means 8 determines that GHP is present,
When the determination signal is input to the control circuit 1, the operation is performed under the control of the control circuit 1, and the control signal output from the control circuit 1 at a constant interval is changed to a random output interval and input to the ultrasonic sensor drive circuit 2. . When the output interval of the control signal is randomly changed by the drive interval varying means 9, the timing of the flow rate detection by the ultrasonic sensor 3 does not coincide with the pressure fluctuation, and the flow rate is detected at a point where the flow rate fluctuation value is large and a point where the flow rate fluctuation value is small. By averaging this, an accurate flow rate that is not affected by pressure fluctuation can be measured.

The average flow rate is obtained from the measured flow rate values by the flow rate averaging shutoff determination means 10, and when the average flow rate value exceeds a preset flow rate value, a shutoff signal is output to the shutoff valve drive circuit 5. Therefore, the shut-off valve drive circuit 5
Is operated to shut off the gas flow path 4.

In the case where the GHP is installed upstream of the gas flow path 4, in the prior art, the shut-off valve 6 is operated at the flow rate of the peak value (A) of the flow rate fluctuation, and the actual flow rate Was erroneously determined to be equal to the average flow rate value, and an erroneous cut-off was made. However, after the flow rate averaging, the cut-off determining means 10 determines whether the average flow rate has exceeded a preset flow rate value. And the erroneous operation of the shut-off valve 6 are eliminated. Therefore, the gas flow path 4 is shut off by accurate abnormality detection, and a highly reliable gas safety device can be provided.

[0027]

As described above, according to the present invention, it is possible to detect the installation of a gas appliance which generates a pressure fluctuation which hinders the measurement of the gas flow rate using the ultrasonic sensor. When it is detected that a gas appliance that generates this pressure fluctuation is present, the driving interval variable means for randomly changing the driving interval of the ultrasonic sensor so as not to affect the measurement of the gas flow rate due to the pressure fluctuation, so that the accurate gas flow rate is obtained. Can be measured. Further, by measuring the gas flow rate, an excessive gas flow rate can be accurately detected, and a highly reliable gas shut-off 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 safety device according to a second embodiment.

FIG. 4 is a graph illustrating a change in a drive interval of an ultrasonic sensor corresponding to a pressure change.

FIG. 5 is a block diagram showing a configuration of a gas security device according to a third embodiment.

FIG. 6 is a graph illustrating setting of a flow rate for operating a shutoff valve.

FIG. 7 is a block diagram showing a configuration of a gas security 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 Shutoff valve drive circuit 6 Shutoff valve 8 GHP judgment means (Pressure fluctuation occurrence judgment means) 9 Driving interval variable means 10 Shutdown judgment means after flow rate averaging

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Norio Niimura 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 72) Inventor Hiroshi Fujii 1006 Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Kazutaka Asano 1006 Odaka Kazuma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 23, Minami-Kashima, Futama-machi, Tenryu-shi, Japan Yazaki Sogo Co., Ltd. (72) Inventor Tominori Yamashita 23, Minami-Kashima, Futamata-cho, Tenryu-shi, Shizuoka Pref. No. 23, Minami Kashima-cho, Yazaki Corporation (72) Inventor Jiro Mizukoshi 2975, Motoe, Shinminato-shi, Toyama Toyo Gas Meter (72) Inventor Noboru Nono 2975 Motoe, Shinminato-shi, Toyama Toyo Gas Meter Co., Ltd. (72) Inventor Fujio Hori 2975 Motoe Motoe, Shinminato-shi, Toyama Toyo Gas Meter Co., Ltd. F-term (reference) 2F030 CA03 CB01 CB09 CC13 CE02 CE04 CF05 CF11 3K003 FB05 GA03

Claims (3)

[Claims] 1. An ultrasonic sensor for detecting an instantaneous flow rate of a gas flowing in a gas flow path, an ultrasonic sensor driving circuit for driving the ultrasonic sensor, and a control signal for measuring a flow rate in the ultrasonic sensor driving circuit. And a control circuit for calculating the gas flow rate from the instantaneous flow rate detection data input from the ultrasonic sensor drive circuit and outputting a shutoff signal when an abnormality is detected in the gas flow rate, and shutting off the gas flow path. A shutoff valve, a shutoff valve driving circuit that drives the shutoff valve by a shutoff signal output from the control circuit, and a number of times that the gas flow rate exceeds a predetermined fluctuation range during a predetermined unit time. A gas safety device comprising: pressure fluctuation occurrence determining means for determining that a pressure fluctuation generating gas appliance is installed in a gas flow path when a predetermined number of times is exceeded. 2. An ultrasonic sensor for detecting an instantaneous flow rate of a gas flowing in a gas flow path, an ultrasonic sensor drive circuit for driving the ultrasonic sensor at a predetermined drive interval, and a flow rate measurement for the ultrasonic sensor drive circuit. A control circuit that outputs a control signal for calculating the gas flow rate from the instantaneous flow rate detection data input from the ultrasonic sensor drive circuit, and outputs a cutoff signal when an abnormality is detected in the gas flow rate; A shut-off valve for shutting off the flow path, a shut-off valve driving circuit for driving the shut-off valve by a shut-off signal output from the control circuit, and the gas flow rate is set to a predetermined fluctuation range during a predetermined unit time. When the number of times exceeds a predetermined number of times, a pressure fluctuation occurrence determining means for determining that a pressure fluctuation generating gas appliance is installed in the gas flow path, and the pressure fluctuation occurrence determining means A gas safety device comprising: a drive interval variable unit that randomly changes a drive interval of the ultrasonic sensor when it is determined that a pressure fluctuation generating gas appliance is installed. 3. A flow rate averaging shutoff judging means for outputting a shutoff signal to a shutoff valve drive circuit when an average value of a predetermined number of measured flow rates becomes equal to or higher than a preset flow rate. 2. The gas safety device according to 2.