JP2014032108A - Gas shut-off device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas shut-off device capable of determining and notifying an abnormality and even when the influence of a reverberation signal caused from variation inherent to ultrasonic-wave transceiver.SOLUTION: The gas shut-off device includes: a flow rate calculation section 7 that calculates the flow rate of a gas based on a propagation time measured by a flow rate measurement section 4; a flow rate storage 8 that stores the flow rate value calculated by the flow rate calculation section 7; a gas estimation section 9 that estimates the type of the gas measured by the flow rate measurement section 4 based on the propagation time; an abnormality detection section 10 that determines as abnormal when the gas estimation section 9 determines that the gas is not a fuel gas but the air, and when the flow rate value stored in the flow rate storage 8 is out of a predetermined range in the forward and the backward directions exceeding a predetermined times; an error detection selecting section 11 that selects whether the function of the abnormality detection section 10 is valid or invalid; and an alarm section 12 that displays an alarm when determined as abnormal.

Description

  The present invention relates to an electronic gas shut-off device using ultrasonic measurement or the like for improving gas use safety and improving gas use convenience when using a gas after the gas shut-off device.

  When using gas appliances, in order to prevent accidents caused by forgetting to turn off gas or leaking gas, etc., the gas business operator managing the gas user's home and the gas supply path should notify the Gas security devices that block supply paths are becoming widespread.

  As a conventional gas security device, based on the gas flow rate, etc., the gas supply is cut off when a large flow rate flows, or the gas flow is cut off when the gas flows for a long time at a minute flow rate. What shuts off when gas flows for a predetermined time is used.

  In a gas user's house or the like, a gas meter for measuring a gas flow rate is installed at an inlet portion of a gas supply path. Conventionally, as this type of gas meter, a membrane-type gas meter that integrates the amount of gas that flows at a predetermined flow rate is generally used, but recently, an instantaneous flow rate is obtained using an ultrasonic signal, and this instantaneous flow rate is calculated. Ultrasonic gas meters that measure the gas flow rate by integrating the values are also installed in the market and tend to increase.

Japanese Patent No. 4792653

  In an ultrasonic gas shut-off device, a measurement flow path in which a pair of ultrasonic transceivers are arranged on the upstream side and the downstream side of the flow path wall, and ultrasonic waves are alternately transmitted and received, so that the order of the gas flow is increased. The ultrasonic propagation time is measured in the opposite direction. And depending on the inherent variation of the ultrasonic transmitter / receiver, since the ultrasonic waves are alternately transmitted / received, the energy at the time of transmitting the ultrasonic waves by the ultrasonic transmitter / receiver remains until the reception of the ultrasonic wave and remains as a received signal A reverberation signal due to energy is synthesized, and the propagation time cannot be measured normally, and the gas flow rate cannot be measured with high accuracy.

  In addition, when a reverberation signal is synthesized with a received signal in an ultrasonic transmitter / receiver, it is necessary to check the variation by changing the temperature because of the influence of temperature.

  However, in the normal gas shut-off device production process, the gas shut-off device needs to work in a place where the temperature is controlled to a certain level when correcting the instrumental differences. When measuring the flow rate at different temperatures, there is a problem that the inspection equipment becomes larger and the inspection tact time becomes longer, so it is difficult to reveal a gas shut-off device that has a large variation in the ultrasonic transceiver in the production process. There was a problem that there was.

The present invention has been made in view of the above circumstances, and is provided with a self-diagnosis function for detecting a measurement abnormality caused by a reverberation signal generated due to inherent variation of an ultrasonic transmitter / receiver, and detects an abnormality only when the gas is air. When actual fuel gas is used, abnormal determination is not performed. Therefore, misjudgment due to fluctuations in gas supply pressure, etc. during use of fuel gas after installation at the gas consumer's home can be prevented. An object of the present invention is to provide a gas shut-off device capable of improving the measurement accuracy and reliability of the amount used.

  The gas cutoff device of the present invention is a forward direction with respect to a gas flow by alternately transmitting and receiving ultrasonic waves with a measurement flow channel in which a pair of ultrasonic transmitters and receivers are arranged on the upstream side and the downstream side of the flow channel wall. A flow rate measurement unit that measures ultrasonic propagation time in the opposite direction, a flow rate calculation unit that calculates the flow rate of gas from the propagation time measured by the flow rate measurement unit and the cross-sectional area of the measurement channel, and the flow rate calculation A flow rate storage unit that stores the flow rate value calculated by the unit, a gas estimation unit that estimates the type of gas measured from the propagation time measured by the flow rate measurement unit, and air instead of fuel gas in the gas estimation unit An abnormality detection unit that determines and determines that an abnormality occurs if the flow rate value stored in the flow rate storage unit is out of a predetermined range in both the forward direction and the reverse direction and occurs more than a predetermined number of times, and the function of the abnormality detection unit An anomaly detection selection section for selecting whether to be valid or invalid, It is composed of a warning unit that performs display or the like when it is determined that normal.

  This provides a self-diagnosis function that the gas shut-off device detects during the storage period after production is completed, and detects abnormalities only when the gas is air. However, when using actual fuel gas, abnormal determination is not performed, so it is possible to prevent misjudgment due to fluctuations in gas supply pressure during use of fuel gas after installation at the gas consumer's home, Since abnormal products can be made apparent before shipment of the gas shut-off device in a normal storage state, it is possible to improve the measurement accuracy and reliability of the amount of gas used when using the gas.

  According to the present invention, there is provided a self-diagnosis function for detecting a measurement abnormality caused by a reverberation signal generated due to inherent variation of an ultrasonic transceiver, and an abnormality is detected only when the gas is air and an actual fuel gas is used. When the fuel gas is installed, it is possible to prevent misjudgment due to fluctuations in the gas supply pressure during use of the fuel gas after it has been installed at the gas consumer's home. Therefore, it is possible to provide a gas shut-off device capable of improving the measurement accuracy and reliability of the amount of gas used during gas use.

The block diagram which shows the structure of the gas interruption | blocking apparatus in Embodiment 1. FIG. Configuration diagram of the flow measurement unit of the gas shutoff device The figure which shows the transmission waveform and reception waveform of ultrasonic flow measurement in the same gas cutoff device (A) The figure which shows the received wave and reverberation wave of an ultrasonic transceiver, (b) The figure which shows the synthetic | combination wave of the received wave and a reverberation wave (A) Graph showing the relationship between the temperature of an abnormal product and the gas flow rate, (b) Graph showing the relationship between the temperature of a normal product and the gas flow rate The flowchart which shows operation | movement of Embodiment 1. The block diagram which shows the structure of the gas interruption | blocking apparatus of Embodiment 2. FIG.

In the first invention, by transmitting and receiving ultrasonic waves alternately by the measurement flow path in which a pair of ultrasonic transceivers are arranged on the upstream side and the downstream side of the flow path through which the gas flows, and the pair of ultrasonic transceivers, The flow rate of the ultrasonic wave is measured in the forward and reverse directions with respect to the gas flow, and the flow rate of the gas is calculated from the propagation time measured by the flow rate measurement unit and the cross-sectional area of the measurement channel. A flow rate calculation unit, a flow rate storage unit that stores the flow rate value calculated by the flow rate calculation unit, a gas estimation unit that estimates the type of gas from the propagation time measured by the flow rate measurement unit, and the gas estimation The flow rate calculated by the flow rate calculation unit is less than or equal to a predetermined value, and the flow rate value in the reverse direction and the flow rate value in the forward direction stored in the flow rate storage unit is within a predetermined range. Abnormal when the number of times outside is greater than or equal to the specified number And a warning unit that gives a notification when the abnormality detection unit determines that an abnormality has occurred.

  This provides a self-diagnosis function that the gas shut-off device detects during the storage period after production is completed, and detects abnormalities only when the gas is air. However, when using actual fuel gas, abnormal determination is not performed, so it is possible to prevent misjudgment due to fluctuations in gas supply pressure during use of fuel gas after installation at the gas consumer's home, Since abnormal products can be made apparent before shipment of the gas shut-off device in a normal storage state, it is possible to improve the measurement accuracy and reliability of the amount of gas used when using the gas.

  According to a second aspect of the invention, particularly in the first aspect of the invention, after the abnormality detection selection unit that selects whether the function of the abnormality detection unit is valid or invalid, By providing an invalid timer unit that disables the function of the abnormality detection unit when a predetermined time has elapsed, the abnormality detection selection unit is automatically invalidated so that the air barge work at the time of installation in the field remains valid It is possible to prevent the risk of an abnormality being determined by the abnormality detection unit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a gas cutoff device according to the present embodiment.

  In the present embodiment, a configuration example of a gas cutoff device using a gas meter installed in a gas user's house or the like will be described.

  A gas shut-off device 30 installed at a predetermined position outdoors or indoor includes a shut-off valve 3 for shutting off a gas passage 2 provided in the gas supply pipe 1, a flow rate measuring unit 4 connected to the gas supply pipe 1, and a gas The control unit 5 that shuts off the gas, displays the gas pointer value, the measurement control unit 6 that controls the flow rate measurement unit 4 to measure the propagation time of the ultrasonic wave, and the propagation time measured by the flow rate measurement unit 4 From the flow rate calculation unit 7 that calculates the gas flow rate from the cross-sectional area of the measurement flow path 35, the flow rate storage unit 8 that stores the flow rate value calculated by the flow rate calculation unit 7, and the propagation time measured by the flow rate measurement unit 4 Functions of the gas estimation unit 9 for estimating the type of gas to be measured, the abnormality detection unit 10 for detecting the presence / absence of an abnormality from the flow rate value stored in the flow rate storage unit 8 by the gas estimation unit 9, and the function of the abnormality detection unit 10 are effective. Anomaly detection selection unit 11 that selects whether or not the It is composed of a warning unit 12 which performs like.

  Here, the abnormality detection unit 10 determines that the gas estimation unit 9 determines that the gas is not fuel gas but air, and the flow rate value stored in the flow rate storage unit 8 is outside the predetermined range in both the forward direction and the reverse direction. If it occurs more than a predetermined number of times, it is determined as abnormal.

  Next, the flow rate measuring unit 4 will be described with reference to FIGS.

  FIG. 2 is a configuration diagram showing a schematic configuration of the ultrasonic flowmeter in the present embodiment, and FIG. 3 is a configuration diagram showing a measurement method of the ultrasonic flowmeter in the present embodiment.

  As shown in FIG. 2, the flow rate measuring unit 4 has a measurement channel 35 that communicates with the gas supply pipe 1, and a pair of channels are provided on the upstream side and the downstream side of the opposite channel walls of the measurement channel 35. Ultrasonic transmitters / receivers 36 and 37 are arranged. These ultrasonic transceivers 36 and 37 are set so that the ultrasonic propagation path obliquely crosses the gas flow flowing through the measurement flow path 35, and by transmitting and receiving ultrasonic waves alternately under the control of the measurement control unit 6. The ultrasonic wave is propagated in the forward direction and the reverse direction with respect to the gas flow.

  As shown in FIG. 2, the measurement of the propagation time will be described later when measuring the ultrasonic propagation time until the ultrasonic wave transmitted from one ultrasonic transmitter / receiver reaches the other ultrasonic transmitter / receiver. In addition, the reception signal is processed in a time until a reception wave having a predetermined magnitude passes a predetermined threshold. At this time, the distance between the ultrasonic transceivers 36 and 37, that is, the measurement distance is L, the angle of the ultrasonic propagation path with respect to the gas flow is φ, and the ultrasonic propagation time from the upstream to the downstream of the ultrasonic transceivers 36 and 37 is If t1, the ultrasonic wave propagation time from the downstream to the upstream is t2, and the sound velocity is C, the flow velocity V is obtained by the following equation.

V = L / 2 cos φ ((1 / t1) − (1 / t2)) (1)
Next, an operation for revealing an abnormal measurement product due to a reverberation signal generated due to inherent variation of the ultrasonic transmitter / receiver will be described with reference to FIGS.

  FIG. 4 is a diagram for explaining a mechanism in which the propagation time cannot be normally measured.

  4A shows the waveform of the received signal (received wave) and the waveform of the reverberant signal (reverberant wave) individually. FIG. 4B shows the waveform (synthesized wave) obtained by synthesizing these two waveforms. That is, an output waveform of the ultrasonic transmitter / receiver and a part A part thereof are enlarged.

  As shown in FIG. 4B, when the transmission energy generated at the time of transmission is continued in the ultrasonic transceivers 36 and 37 and the transmission energy remains as a reverberation signal until the next reception, In this case, the received signal and the reverberant signal become a combined waveform, which is different from the actual received signal.

  Since the propagation time (t1, t2) is measured by using the point (zero cross point) at which the received wave first crosses at a voltage 0 after the predetermined voltage Va is exceeded as the reception point, the reception point (zero cross point a) of the original received signal is measured. ) And the reception point (zero cross point b) of the synthesized wave, a propagation time difference (Δt) occurs, and an error occurs in the measurement of the ultrasonic propagation time.

  FIG. 5 shows the relationship between the temperature and the measured gas flow rate. FIG. 5A shows the case where the ultrasonic transceiver is abnormal, and FIG. 5B shows the case where it is normal. .

  Since the sound velocity of the measured propagation time changes depending on the temperature, the combined waveform of the reverberation signal and the received signal changes depending on the temperature, and the zero point fluctuates periodically as the temperature changes. And a product with a large reverberation signal has a flow rate value outside the predetermined range in both the forward direction and the reverse direction. Here, the reason why the fluctuation is larger at a higher temperature is because the propagation time is shorter and the measurement accuracy is more affected.

  In the present embodiment, as shown in FIG. 5, when the ultrasonic transmitter / receiver is abnormal, the fact that the measured flow rate greatly fluctuates depending on the temperature is used. Judgment is made by the number of times exceeding the range.

  For example, in FIG. 5, there are three waves between ΔT (about 9 ° C.) from 20 ° C. to 30 ° C., so there is a peak in the forward and reverse directions in the range of about 3 ° C. I understand. Therefore, it is possible to detect an abnormal product in an environment with a temperature change of about 3 ° C.

  Next, the abnormality determination operation of the present embodiment will be described in detail with reference to the flowchart shown in FIG.

  First, the abnormality detection selection unit 11 detects whether or not abnormality detection by the abnormality detection unit 10 is valid (S101).

  The abnormality detection selection unit 11 selects whether the function of the abnormality detection unit 10 is valid or invalid by using a test cutoff switch using a reed switch installed on the control board of the gas cutoff device or setting communication from the outside. .

  If the abnormality detection is not effective, the following processing is not performed. If it is effective, the gas estimation unit 9 determines whether the gas is air (S102).

  The gas estimation unit 9 estimates the gas from the propagation time depending on the type of gas. The relationship between the propagation time of fuel gas and air used in Japan is as follows: natural gas <air <liquefied petroleum gas, and the gas is estimated by judging whether it is within the predetermined propagation time range for each gas. It is. Note that the relationship between the received signal of fuel gas and air used in Japan is as follows: natural gas <air <liquefied petroleum gas, and it is possible to estimate the gas not by the propagation time but by the magnitude of the received signal. is there.

  If the gas is not air, the following processing is not performed. If the gas is air, the flow rate calculation unit 7 calculates the gas flow rate from the gas flow velocity calculated from the propagation time and the cross-sectional area of the measurement channel 35. Calculation is performed (S103).

  Next, it is determined whether or not the flow rate measured by the flow rate calculation unit 7 is within a predetermined flow range, that is, a flow rate that can be regarded as a gas not flowing (S104). When the following processing is not performed and the flow rate is within the predetermined flow range, first, it is determined whether or not the positive flow rate exceeds a predetermined value (S105), and if it exceeds, the number of times the predetermined flow rate is exceeded in the positive direction is counted. (S106).

  Then, it is determined whether the reverse flow rate exceeds a predetermined value (S107), and if it exceeds, the number of times the predetermined flow rate is exceeded in the reverse direction is counted (S108).

  The flow rate storage unit 8 stores the flow rate and the number of times when the flow rate in the forward direction and the reverse direction, which are variations in flow rate measurement in a state where no air is flowing, is outside the predetermined value range. In addition, it is considered useful to provide a predetermined value range for each gas shut-off device with the flow rate in the forward direction and the reverse direction.

  A determination is made as to whether the number of forward and reverse flow rates outside the predetermined value range stored in the flow rate storage unit 8 is equal to or greater than a predetermined number (S109). (S110).

  The abnormality detection unit 10 is stored in the flow rate storage unit 8 as a variation in flow rate measurement in a state where the air is not intentionally flowing when the gas in the measurement channel 35 is air instead of fuel gas in the gas estimation unit 9. If the flow rate value is out of the predetermined range in both the forward direction and the reverse direction and occurs more than a predetermined number of times, it is determined that there is an abnormality.

  The warning unit 12 performs display using a liquid crystal or LED, or reports to a gas company using a communication line. When the abnormality detection unit 10 determines that an abnormality has occurred, the warning unit 12 performs notification.

  Here, the control unit 5, the measurement control unit 6, the flow rate calculation unit 7, the flow rate storage unit 8, the gas estimation unit 9, the abnormality detection unit 10, and the abnormality detection selection unit 11 are a processor that constitutes a microcomputer (microcomputer) and the like. Each function is realized by executing a predetermined operation program in a processor and performing a corresponding process.

  As a result, it is possible to provide a self-diagnosis function for detecting an abnormality in measurement due to a reverberation signal generated by the inherent variation of the ultrasonic transmitter / receiver, and to detect an abnormality only when the gas is air and use the actual fuel gas. Since the abnormality determination is not performed during the operation, erroneous determination due to fluctuations in gas supply pressure or the like can be prevented during use of the fuel gas after being installed at the gas consumer's home.

  Also, in normal storage conditions, the temperature change in the storage environment is about several degrees Celsius, so it is possible to catch the fluctuation range peak in abnormal products as shown in FIG. Products can be revealed. Therefore, it becomes possible to improve the measurement accuracy and reliability of the amount of gas used when using the gas.

(Embodiment 2)
Next, a second embodiment of the present invention will be described.

  FIG. 7 is a block diagram showing the configuration of the gas cutoff device in the present embodiment.

  In the first embodiment, the present invention provides an abnormality detection selection unit 11 for selecting whether to enable or disable the abnormality detection unit, and after enabling the function in the abnormality detection selection unit 11 When the predetermined time has elapsed, the abnormality detection selection unit 11 automatically includes an invalid timer unit 40 that invalidates the function of the abnormality detection unit 10.

  Thus, by automatically disabling the abnormality detection selection unit 11, there is a risk that the abnormality detection unit determines an abnormality based on the flow rate measured by the flow rate calculation unit 7 during air barge work at the time of installation at the site if enabled. Can be prevented.

  That is, during air barge, a so-called mixed gas state in which air and fuel gas are mixed is present, and the measured flow rate may fluctuate. However, according to this configuration, such a problem can be avoided.

  Here, the invalid timer unit 40 is constituted by a processor and an operation program constituting a microcomputer or the like, and the function is realized by executing a predetermined operation program and performing corresponding processing in the processor.

  The present invention is provided with a self-diagnosis function for detecting a measurement abnormality caused by a reverberation signal generated due to inherent variation of an ultrasonic transmitter / receiver, and when an abnormality is detected only when the gas is air and an actual fuel gas is used. Because it does not perform abnormality determination, it can prevent misjudgment due to fluctuations in gas supply pressure while using fuel gas after it has been installed at the gas consumer's home, thereby improving gas safety It is useful for a gas shut-off device capable of

DESCRIPTION OF SYMBOLS 1 Gas supply pipe 2 Gas passage 3 Shut-off valve 4 Flow rate measurement part 5 Control part 6 Measurement control part 7 Flow rate calculation part 8 Flow rate memory | storage part 9 Gas estimation part 10 Abnormality detection part 11 Abnormality detection selection part 12 Warning part 30 Gas cutoff device 35 Measurement channel 36, 37 Ultrasonic transmitter / receiver 40 Invalid timer unit

Claims (2)

A measurement flow path in which a pair of ultrasonic transceivers are arranged on the upstream side and the downstream side of the flow path through which the gas flows;
A flow rate measurement unit that measures the propagation time of ultrasonic waves in the forward direction and the reverse direction with respect to the gas flow by alternately transmitting and receiving ultrasonic waves by the pair of ultrasonic transceivers,
A flow rate calculation unit that calculates a flow rate of the gas from a propagation time measured by the flow rate measurement unit and a cross-sectional area of the measurement channel;
A flow rate storage unit for storing the flow rate value calculated by the flow rate calculation unit;
A gas estimation unit that estimates the type of gas from the propagation time measured by the flow rate measurement unit;
When the gas estimation unit determines that the gas is air, the flow rate calculated by the flow rate calculation unit is equal to or less than a predetermined value, and the flow rate value in the direction opposite to the forward flow rate value stored in the flow rate storage unit An abnormality detection unit that determines that an abnormality occurs when the number of times that is outside the predetermined range is equal to or greater than the predetermined number of times,
A gas shut-off device comprising: a warning unit that notifies when the abnormality detection unit determines that an abnormality has occurred. An abnormality detection selection unit for selecting whether the function of the abnormality detection unit is valid or invalid;
The gas shut-off device according to claim 1, further comprising: an invalid timer unit that disables the function of the abnormality detection unit after a predetermined time has elapsed after enabling the function of the abnormality detection unit in the abnormality detection selection unit. .