JP5537052B2 - Gas shut-off device - Google Patents

Description

  In the present invention, when a sensor of a gas shut-off device judges an abnormality and shuts off the gas, in the case of a transient abnormality due to air mixing into the gas, the abnormality is canceled and the gas can be used.

Conventionally, as shown in FIG. 3, this type of gas shut-off device includes a flow rate detection unit 1 that outputs a flow rate signal a corresponding to a gas flow rate passing through a gas passage, and the flow rate signal a of the flow rate detection unit 1. The flow rate calculation unit 2 that calculates the flow rate b when received, and the abnormal flow rate determination unit that outputs the valve closing signal c if the flow rate b of the flow rate calculation unit 2 is abnormal when compared with the determination value held in advance. 3 and a valve drive unit that outputs a valve drive signal d when the valve close signal c of the abnormal flow rate determination unit 3, the valve open signal e of the return input unit 8, or the valve close signal c of the sensor abnormality determination unit 6 is received. 4, the valve 5 that opens or closes the gas passage when the valve drive signal d of the valve drive unit 4 is received, and whether the flow rate signal a of the flow rate detection unit 1 meets a predetermined abnormal condition Check whether the valve is The sensor abnormality determination unit 6 that outputs the signal c, the integration unit 7 that integrates and holds the flow rate b when the flow rate b of the flow rate calculation unit 2 is received, and the valve opening signal that receives a return input from the outside It was comprised from the said return input part 8 which outputs e (for example, refer patent document 1).
Japanese Patent No. 3624642

  However, in the conventional configuration, abnormal flow determination, sensor abnormality determination, and integration are performed based on the flow signal a detected by the flow detection unit 1, so that the flow type signal a Different gases are mixed inhomogeneously (for example, air mixing at the time of heat conversion or installation / replacement of a gas shut-off device). Since it is transmitted, there is a possibility that the flow rate is unexpected.

  The flow rate measurement of the ultrasonic gas shut-off device is configured to switch the transmission and reception of the sensor from the upstream side to the downstream side and from the downstream side to the upstream side, and obtain the flow velocity from the difference in the propagation time T. That is, the ultrasonic wave output from the sensor on the transmitting side is acquired as a waveform as shown in FIG. 4 on the receiving side, and the time when the third wave exceeds the third wave and zero crosses for the first time is measured as the propagation time T. Yes. For this reason, if the entire waveform is not an appropriate size, an abnormal flow velocity is calculated.

  In order to create an appropriate waveform, the gain is corrected so that the maximum peak of the waveform falls between VH and VL so that the third wave of the waveform always exceeds the V level for the first time. Therefore, when the gain correction requires unexpected fluctuations (when the gain increases or decreases cannot be followed, or when an appropriate waveform cannot be obtained due to sticking to the upper and lower limits). There is a possibility that the measured flow velocity becomes abnormal (for example, when the V level exceeds the V level for the first time at the second or fourth wave, or when the peak of all waveforms does not exceed the V level).

  Therefore, when the gain correction becomes unexpected, it is determined and gas is shut off as a sensor abnormality, and the state is maintained in view of safety.

  However, the causes of sensor abnormalities include those due to permanent failure of the device and those that are transient due to air mixing into the gas. Had.

  The present invention solves the above-described conventional problems, and is caused by a mixture of gas and air (for example, the timing of shutting down and returning including the time of heat conversion or installation / replacement of a gas shut-off device). It is an object of the present invention to provide a gas shut-off device that is configured so that the shut-off state caused by the sensor abnormality can be restored by external input, and can be re-used by maintenance at the installation site.

  In order to solve the conventional problem, the gas cutoff device of the present invention outputs a sensor abnormality release signal to the sensor abnormality release input unit when the sensor abnormality determination unit determines a sensor abnormality that may be transient, The sensor abnormality canceling input unit outputs an opening signal to the valve driving unit when an external input is received at that timing, and the shut-off valve is restored.

  As a result, it is possible to release the shut-off state of the valve caused by a temporary sensor abnormality due to mixing of gas and air.

  The gas shut-off device of the present invention shuts off gas when a sensor abnormality occurs, and enables the use of gas by releasing the gas shut-off for a transient abnormal event due to the cause of the sensor abnormality. Therefore, it is possible to ensure the safety of occurrence of abnormality, and it is possible to reuse the gas by maintenance at the installation site, thereby improving convenience.

According to a first aspect of the present invention, there is provided a flow rate detection unit that outputs a flow rate signal corresponding to a gas flow rate passing through the gas passage, a flow rate calculation unit that calculates a flow rate when receiving the flow rate signal of the flow rate detection unit, and the flow rate When the flow rate of the calculation unit is received, an abnormal flow rate determination unit that outputs a valve closing signal if it is abnormal as compared with a determination value held in advance, and the valve closing signal of the abnormal flow rate determination unit or the valve of the return input unit A valve drive unit that outputs a valve drive signal when receiving the valve open signal of the valve open signal or the sensor abnormality release input unit of the sensor abnormality determination unit or a gas when receiving the valve drive signal of the valve drive unit A valve that opens or closes the passage, a return input unit that outputs the valve opening signal when a return input is received from the outside when the abnormal flow rate determination unit determines an abnormal flow rate, and a flow rate signal of the flow rate detection unit Received flow rate From the above situation, it is judged whether there is a steady abnormality due to a device failure or an abnormality that may be transient due to air in the gas, and if there is an abnormality that may be transient, a sensor abnormality release signal is output. A sensor abnormality determination unit that is effective when receiving a sensor abnormality cancellation signal from the sensor abnormality determination unit, and receives an abnormality cancellation input from the outside and outputs a valve opening signal to the valve drive unit, When the valve is closed based on a valve closing signal from the abnormal flow rate determination unit, the gas blocking device is configured to open the valve by a valve opening signal of the sensor abnormality cancellation input unit.

  According to the second invention, particularly when the sensor abnormality determination unit of the first invention determines that the sensor abnormality is not resolved within a predetermined time after the sensor abnormality cancellation input unit receives the abnormality cancellation input, By determining that it is a steady abnormality and not outputting a sensor abnormality release signal, it is possible to judge a steady failure that cannot be distinguished from an abnormality that may be transient due to the flow signal state, and to cancel the abnormality. It can be.

  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 shows a functional block diagram of a gas cutoff device in Embodiment 1 of the present invention.

  In FIG. 1, the flow rate detection unit 11 outputs a flow rate signal A corresponding to the gas flow rate passing through the gas passage (for example, an ultrasonic sensor facing the gas passage is attached, and the gas is detected due to the difference in ultrasonic propagation time. Detect the flow rate).

  When the flow rate calculation unit 12 receives the flow rate signal A from the flow rate detection unit 11, the flow rate calculation unit 12 calculates the flow rate B.

  When the abnormal flow rate determination unit 13 receives the flow rate B of the flow rate calculation unit 12, the determination value held in advance (for example, the maximum flow rate gas flow allowed by the gas shut-off device may be used, or a small amount of gas flow rate continues. The valve closing signal C is output if there is an abnormality as compared with the case where the allowable time is exceeded after the flow continues.

  When the valve drive unit 14 receives the valve close signal C of the abnormal flow rate determination unit 13, the valve open signal E of the return input unit 16 or the valve close signal C of the sensor abnormality determination unit 18, the valve drive signal D (for example, opens the valve 15). Output a signal to drive the stopper or the stopper.

  When the valve 15 receives the valve drive signal D of the valve drive unit 14, the valve 15 opens or closes the gas passage.

  When the return input unit 16 receives a return input from the outside (for example, an input by a button, a non-contact type such as a reed switch, or the same effect can be obtained by an input by a communication message), a valve opening signal is received. E is output.

  When the sensor abnormality determination unit 17 receives the flow signal A, it compares the information held by the flow signal A with a determination value held in advance, and determines that the sensor abnormality is detected when the flow signal A is in an unexpected range. C is output. At the same time, it is determined from the information of the flow rate signal A whether it is a steady abnormality due to a device failure or a transient abnormality that may be caused by air in the gas. Abnormality cancellation signal F is output.

  The sensor abnormality cancellation input unit 18 receives the sensor abnormality cancellation signal F, receives the sensor abnormality cancellation signal F, and inputs an abnormality cancellation input from the outside (an input by a button or a non-contact type such as a reed switch may be used. The valve opening signal E is output when a simultaneous input of them or an input by a communication message can obtain the same effect).

  The flow rate detection unit 11 is an ultrasonic velocity sensor, and the flow rate measurement is performed by switching the transmission and reception of the sensor from the upstream side to the downstream side and from the downstream side, obtaining the flow velocity from the difference in the propagation time T, and fixing the gas flow The gas flow rate is obtained from the product of the area of the road. In other words, the ultrasonic wave output from the sensor on the transmitting side is acquired as a waveform as shown in the waveform diagram of FIG. 4 on the receiving side, and the time when the third wave exceeds the third level and zero crosses for the first time thereafter is the propagation time T. As measured.

  For example, the sensor abnormality determination unit 17 determines a sensor abnormality when a state in which no signal is detected on the receiving side continues within a predetermined time after the ultrasonic transmission from the transmission side, and the abnormality that has occurred is a malfunction of the transmission abnormality or reception abnormality of the sensor. Therefore, the sensor abnormality release signal F is not output.

  Further, when air is mixed in the gas pipe at the time of heat quantity conversion or when the gas shut-off device is installed / replaced, the peak value of the received waveform shown in FIG. 4 differs between gas and air. The measurement of the propagation time T is based on the time until the zero cross after the third wave of the received waveform exceeds the V level, and therefore the abnormal flow velocity is measured unless the entire waveform is an appropriate size. Therefore, the gain is corrected each time the maximum peak of the waveform falls between VH and VL so that the third wave of the waveform always exceeds the V level for the first time. Since the peak value of the received waveform when the ultrasonic wave passes through the mixed air becomes small, the gain adjustment value becomes large. The sensor abnormality determination unit 17 determines a sensor abnormality when the gain adjustment value exceeds a predetermined value for a predetermined time, and outputs a sensor abnormality cancellation signal F because the generated abnormality is assumed to be mixed in with air.

  The operation and action of the gas shut-off device configured as described above will be described below.

  First, when the information of the flow rate signal A becomes an unexpected state, the sensor abnormality determination unit 17 determines abnormality, outputs a valve closing signal C, and the valve driving unit 14 sets the valve 15 to a gas cutoff state. Further, when the sensor abnormality determination unit 17 determines that the generated abnormality is a transient abnormality such as air mixing, the sensor abnormality cancellation signal F is output to the sensor abnormality cancellation unit 18 to enable an external abnormality cancellation input. As a result, a valve opening signal E is output from the sensor abnormality canceling unit 18, and the valve driving unit 14 returns the valve 15.

  As described above, in the present embodiment, the sensor abnormality determination unit 18 determines a transient abnormality that may be caused by the state of the gas to be measured, and the valve that has been shut off once to ensure safety. Can return. In addition, for obvious sensor failures, the shut-off can be continued and the valve cannot be restored.

(Embodiment 2)
FIG. 2 shows a time chart of the gas cutoff device according to Embodiment 2 of the present invention. In the second embodiment, the following features are added to the sensor abnormality determination unit 17 of the gas cutoff device of the first embodiment.

  In FIG. 2, the sensor abnormality determination unit 17 determines a sensor abnormality when the gain adjustment value exceeds the threshold value G1 for a predetermined time (t1), outputs a valve closing signal C, and shuts off (closes) the valve. The release signal F is output. The sensor abnormality cancellation input unit 18 outputs a valve opening signal E when the abnormality cancellation input is received from the outside (t2), and the valve returns (opens). At the same time, the fact that the abnormality cancellation input has been received is output to the sensor abnormality determination unit 17 (signal G in FIG. 1). The sensor abnormality determination unit 17 counts a timer for a predetermined time t from the time (t2) when the signal G is received, and determines a sensor abnormality when the gain of the flow signal A does not fall below the threshold G2 (G1 ≧ G2) during t. The valve closing signal C is output to shut off (close) the valve. At that time, the sensor abnormality determination unit 17 does not output the sensor abnormality cancellation signal F.

The operation and action of the gas shut-off device configured as described above will be described below.
First, the gain adjustment value increases when the output of the ultrasonic signal is small due to some failure of the transmitter of the sensor, as in the case where the ultrasonic wave passes through the air. That is, an event in which the gain adjustment value becomes large appears in a steady failure due to a device failure as well as a transient abnormality.

  Therefore, when the gain adjustment value of the signal exceeds the threshold value G1 (t1), it is determined that there is a possibility that the air is mixed in the gas pipe and there is a possibility of a transient, and the sensor abnormality canceling signal F is output. This makes it possible to cancel the sensor abnormality. When the sensor abnormality is canceled and the valve 15 is returned (t2), the gain adjustment value is further monitored for a predetermined time t. If the value is not less than a sufficiently large threshold G2, it is determined that the sensor abnormality is a steady sensor abnormality (t3). ) At time t3, since the sensor abnormality release signal F is not output, the sensor abnormality cannot be released by external input, and the shut-off state of the valve 15 continues.

  As described above, in the present embodiment, even after the sensor abnormality determination unit 18 cancels the sensor abnormality, the abnormality determination of the same factor is performed, so that a steady abnormality due to the failure of the apparatus or a transient state due to the gas state Can be accurately determined.

  In the first and second embodiments, the gas is shut off due to the occurrence of a sensor abnormality to ensure safety, and the sensor or measurement circuit is physically damaged or malfunctioned. By separating abnormalities based on abnormal flow rate signals and canceling erroneous sensor abnormalities based on transient abnormal flow rate signals through maintenance at the installation site, gas can be reused and convenience can be improved. it can.

  As described above, the gas shut-off device according to the present invention can cancel the sensor abnormality caused by the transient abnormal flow signal by the maintenance at the installation site. Therefore, convenience can be improved while ensuring safety. Therefore, if gas is replaced with water, it can be applied to uses such as a water meter.

Functional block diagram of the gas cutoff device in Embodiment 1 of the present invention Time chart of gas cutoff device in embodiment 2 of the present invention Functional block diagram of a conventional gas shut-off device Waveform diagram showing received waveform

DESCRIPTION OF SYMBOLS 11 Flow rate detection part 12 Flow rate calculation part 13 Abnormal flow rate determination part 14 Valve drive part 15 Valve 16 Return input part 17 Sensor abnormality determination part 18 Sensor abnormality cancellation input part

Claims (2)

A flow rate detection unit that outputs a flow rate signal corresponding to a gas flow rate passing through the gas passage, a flow rate calculation unit that calculates a flow rate when receiving the flow rate signal of the flow rate detection unit, and the flow rate of the flow rate calculation unit An abnormal flow rate determination unit that outputs a valve closing signal if it is abnormal when compared with a determination value held in advance, and a valve opening signal or sensor abnormality determination of the valve closing signal of the abnormal flow rate determination unit or the return input unit A valve drive unit that outputs a valve drive signal when receiving the valve close signal of the valve or the valve opening signal of the sensor abnormality cancel input unit, and a gas passage is opened or closed when the valve drive signal of the valve drive unit is received And a return input unit that outputs the valve opening signal when a return input is received from outside when the abnormal flow rate determination unit determines an abnormal flow rate, and a flow rate signal of the flow rate detection unit that receives a flow rate signal of the flow rate detection unit Dress It is judged whether it is a stationary abnormality due to a malfunction of the gas or an abnormality that may be transient due to air mixing in the gas, and in the case of an abnormality that may be transient, a sensor abnormality determination that outputs a sensor abnormality release signal And a sensor abnormality cancellation input unit that becomes effective when receiving a sensor abnormality cancellation signal from the sensor abnormality determination unit and receives an abnormality cancellation input from the outside and outputs a valve opening signal to the valve drive unit, and the abnormal flow determination A gas shut-off device, wherein when the valve is closed based on a valve closing signal from a section, the valve is opened by a valve opening signal of the sensor abnormality cancellation input section.   When the sensor abnormality determining unit determines that the same sensor abnormality is not resolved within a predetermined time after the sensor abnormality canceling input is received by the sensor abnormality canceling input unit, the sensor abnormality determining unit determines that it is a steady abnormality due to a device failure and cancels the sensor abnormality. The gas shut-off device according to claim 1, wherein no signal is output.

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