JP3913434B2 - Gas security device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas security device that measures a gas flow rate and shuts a gas passage when an abnormal flow rate is measured, thereby ensuring safety in using the gas.
[0002]
[Prior art]
2. Description of the Related Art In recent years, gas safety devices that measure the amount of gas used and shut off the gas when an abnormality has occurred have started to use ultrasonic sensors in order to improve the safety by measuring the instantaneous flow velocity of the gas.
[0003]
A conventional gas safety device of this type will be described with reference to FIG. Usually, an ultrasonic sensor 21, a flow path 22 with a clear cross-sectional area, a shut-off valve 23 that shuts off the flow path 22, a shut-off valve drive circuit 24 that drives the shut-off valve 23, a battery 25 for power supply, A sonic sensor drive circuit 26 and a control circuit 27 for performing various determination controls are provided.
[0004]
When measuring the flow rate, a signal is sent from the control circuit 27 to the ultrasonic sensor drive circuit 26 at a predetermined time interval, and a signal corresponding to the flow velocity of the gas flowing in the flow path 22 is detected by the ultrasonic sensor 21. The flow rate is obtained from the detection signal at, and the instantaneous flow rate is measured from the gas velocity and the cross-sectional area of the flow path 22. Further, the integrated flow rate of gas is calculated based on the instantaneous flow rate, and it is determined whether or not the gas flow pattern is abnormal. If it is determined that the gas flow pattern is abnormal, a cutoff signal is issued to the cutoff valve drive circuit 24 and the cutoff valve 23 is turned on. Shut off and stop gas.
[0005]
[Problems to be solved by the invention]
However, since the flow rate measurement using an ultrasonic sensor measures the instantaneous flow rate, if the gas pressure fluctuates due to the reliquefaction phenomenon unique to the liquefied petroleum gas supply facility, it cannot be measured normally, and the safety function will be adversely affected. was there.
[0006]
The re-liquefaction phenomenon means that once vaporized gas becomes liquid again at the inlet of the gas pressure regulator, depending on the piping configuration of the liquefied petroleum gas supply equipment and the ambient temperature conditions, and the liquid reaches the outlet of the gas regulator at the start of gas use. This is a phenomenon in which the gas flowing out in the state suddenly vaporizes, and the gas pressure on the downstream side of the gas piping fluctuates.
[0007]
In view of the above conventional problems, an object of the present invention is to provide a gas safety device capable of detecting a re-liquefaction occurrence, obtaining a stable flow rate value, and preventing a malfunction of a safety function.
[0008]
[Means for Solving the Problems]
The gas safety device of the present invention includes an ultrasonic sensor that measures the amount of gas used and an ultrasonic measurement unit that includes a measurement channel, a shut-off valve that shuts off the gas when an abnormality occurs, and various determination controls. In a gas safety device having a control circuit for performing re-liquefaction, a re-liquefaction detection means for detecting a re-liquefaction phenomenon in which the gas pressure fluctuates irregularly, and a re-measurement for averaging the measured flow rate value that fluctuates when re-liquefaction occurs. When the reliquefaction phenomenon is detected, the reliquefaction detection means detects the reliquefaction phenomenon. When the reliquefaction phenomenon occurs, the normal flow rate measurement means is switched to the reliquefaction measurement means. In addition, it is possible to detect the occurrence of reliquefaction based on the pattern of fluctuating flow rate measurement values, and to obtain a stable flow rate value by averaging the fluctuating instantaneous flow rate measurement values. Prevents malfunction of functions That.
[0010]
In addition, when re-liquefaction occurs, a request for improvement of gas supply equipment is communicated to an external center, and a re-liquefaction notification function that displays on the display unit is provided to quickly confirm that re-liquefaction has occurred. Can do.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, each embodiment of the gas security device of the present invention will be described with reference to the drawings.
[0014]
(First embodiment)
First, a gas security device according to a first embodiment of the present invention will be described with reference to FIG. In FIG. 1, an ultrasonic sensor 1, a flow path 2 with a clear sectional area, a shut-off valve 3 that shuts off the flow path 2, a shut-off valve drive circuit 4 that drives the shut-off valve 3, a battery 5 for power supply, , An ultrasonic sensor drive circuit 6, a control circuit 7 that performs all measurement and other controls, a communication interface 8, and a liquid crystal display unit 9.
[0015]
In the present embodiment, the control circuit 7 is provided with a reliquefaction detection means 11 and a reliquefaction measuring means 12. In the liquefaction detection means 11, if the fluctuation range between the instantaneous flow rate measurement value measured by the ultrasonic sensor 1 and the previous measurement value exceeds the predetermined flow rate exceeds a predetermined number of times before the flow rate is not present, the liquefaction detection unit 11 performs re-liquefaction. Therefore, the flow rate measuring means is switched from the normal state to the reliquefaction measuring means 12. The re-liquefaction measuring means 12 is configured to calculate the flow rate calculated at each measurement timing of the normal ultrasonic sensor 1 by averaging the measured values a predetermined number of times and averaging the flow rate.
[0016]
In the above configuration, in a normal state, a signal is sent from the control circuit 7 to the ultrasonic sensor drive circuit 6 at a predetermined time interval, and the ultrasonic sensor 1 detects a signal corresponding to the flow velocity of the gas flowing in the flow path 2, The control circuit 7 obtains the flow rate from the detection signal and measures the instantaneous flow rate from the gas velocity and the cross-sectional area of the flow path 2. Based on this instantaneous flow rate, the integrated gas flow is calculated, and it is determined whether the gas flow pattern is abnormal. If it is determined abnormal, a shutoff signal is sent to the shutoff valve drive circuit 4 and the shutoff valve 3 is shut off. Stop the gas.
[0017]
Further, the re-liquefaction detection means 11 checks the fluctuation range of the instantaneous flow rate measurement value and the previous measurement value, and if the fluctuation range exceeds a predetermined number of times until the state where the fluctuation range is equal to or greater than the predetermined flow rate becomes a state of no flow rate. It is determined that reliquefaction has occurred. In this case, the measurement value is averaged a predetermined number of times by the reliquefaction measuring means 12 to calculate the flow rate. Thereby, even when the reliquefaction phenomenon occurs, the gas flow rate can be normally calculated without being affected by the pressure fluctuation.
[0018]
(Second Embodiment)
Next, a gas security device according to a second embodiment of the present invention will be described with reference to FIG. In the following embodiments, the same components as those described in the above embodiments are denoted by the same reference numerals, description thereof is omitted, and only differences are described.
[0019]
In FIG. 2, in the present embodiment, the control circuit 7 is provided with a reliquefaction number counter 13 and a reliquefaction duration measuring means 14. The reliquefaction number counter 13 records the number of times that the reliquefaction detection means 11 determines that reliquefaction has occurred. In the reliquefaction duration measuring means 14, when it is determined that reliquefaction has occurred in the determination of the reliquefaction detection means 11 when the gas starts to be used, the reliquefaction detection means 11 detects after the gas starts to be used. Measure and record the time until no more fluctuation than the predetermined flow rate fluctuation range occurs.
[0020]
As a result, the number of occurrences of the reliquefaction phenomenon and the degree of the reliquefaction phenomenon can be confirmed at the time of inspection of the gas safety device.
[0021]
(Third embodiment)
Next, a gas security device according to a third embodiment of the present invention will be described with reference to FIG.
[0022]
In FIG. 3, the basic configuration of the present embodiment is the same as that of the second embodiment, and the liquefaction notification means 15 is provided in the control circuit 7. When the re-liquefaction notifying unit 15 determines that re-liquefaction has occurred in the re-liquefaction detecting unit 11, the re-liquefaction notifying unit 11 displays on the liquid crystal display unit 9 that re-liquefaction has occurred, and communicates with the communication interface 8 at a predetermined center. To report that the reliquefaction phenomenon has occurred.
[0023]
Thereby, the gas supply facility in which reliquefaction has occurred can be confirmed at an early stage by the liquid crystal display unit 9 or at the center.
[0024]
(Fourth embodiment)
Next, a gas security device according to a fourth embodiment of the present invention will be described with reference to FIG.
[0025]
In FIG. 4, the present embodiment has the same basic configuration as the third embodiment. The temperature sensor 10 is provided and the detection signal is input to the control circuit 7, and the reliquefaction learning means 16 is provided in the control circuit 7. Is provided. The reliquefaction learning means 16 learns the temperature change at the time of occurrence of reliquefaction measured by the temperature sensor 10 and determines in advance whether reliquefaction will occur.
[0026]
Thereby, it is possible to predict the situation where reliquefaction occurs and take measures.
[0027]
(Fifth embodiment)
Next, a gas security device according to a fifth embodiment of the present invention will be described with reference to FIG.
[0028]
In FIG. 5, this embodiment has the same basic configuration as that of the fourth embodiment. Instead of measuring the temperature with the temperature sensor 10, the ultrasonic sensor 1 uses the change in the sound speed due to the temperature to the control circuit 7. Sonic temperature conversion means 17 for measuring temperature from the propagation time of ultrasonic waves to be measured is provided.
[0029]
Thereby, since it is not necessary to provide the temperature sensor 10, the gas security device can be miniaturized.
[0030]
【The invention's effect】
According to the gas safety device of the present invention, as is apparent from the above description, the reliquefaction detection means for detecting the reliquefaction phenomenon in which the gas pressure fluctuates irregularly, and the measured flow rate value that fluctuates when reliquefaction occurs. The re-liquefaction measurement means that averages the gas is detected, so that when a re-liquefaction phenomenon occurs, this can be detected and the gas flow rate value can be found normally, and the safety function of the gas safety device is re-liquefied. It is possible to prevent malfunction due to the phenomenon.
[0032]
In addition, when reliquefaction occurs, a request for improvement of gas supply equipment is communicated to an external center, and a reliquefaction notification function for displaying on the display unit is provided, so that reliquefaction can be confirmed at an early stage. The equipment can be improved quickly and the period affected by reliquefaction can be shortened.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a first embodiment of a gas security device of the present invention.
FIG. 2 is a block diagram showing a configuration of a second embodiment of the gas security device of the present invention.
FIG. 3 is a block diagram showing a configuration of a third embodiment of the gas security device of the present invention.
FIG. 4 is a block diagram showing the configuration of a fourth embodiment of the gas safety device of the present invention.
FIG. 5 is a block diagram showing a configuration of a fifth embodiment of the gas security device of the present invention.
FIG. 6 is a block diagram showing a configuration of a conventional gas safety device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ultrasonic sensor 2 Flow path 3 Shut-off valve 6 Ultrasonic sensor drive circuit 7 Control circuit 8 Communication interface 9 Liquid crystal display part 10 Temperature sensor 11 Reliquefaction detection means 12 Reliquefaction measuring means 13 Reliquefaction number counter 14 Reliquefaction continuation time Measuring means 15 Reliquefaction reporting means 16 Reliquefaction learning means 17 Sonic temperature conversion means

Claims (2)

An ultrasonic measurement unit configured with an ultrasonic sensor that measures the amount of gas used and a measurement channel, a shut-off valve that shuts off the gas when an abnormality occurs, and a control circuit that performs various determination controls In gas security equipment,
Re-liquefaction detection means for detecting a re-liquefaction phenomenon in which the gas pressure fluctuates irregularly, and a re-liquefaction measuring means for averaging the measured flow rate value that fluctuates when re-liquefaction occurs,
A gas safety device that switches from a normal flow rate measurement means to the re-liquefaction measurement means when a re-liquefaction phenomenon is detected by the re-liquefaction detection means . The gas security device according to claim 1, further comprising a reliquefaction notification function for communicating a request for improvement of the gas supply facility to an external center and displaying on a display unit when reliquefaction occurs .

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