JP3863335B2 - Gas security device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas security device installed in a gas passage, and more particularly to a gas security device configured to detect and display a gas type.
[0002]
[Prior art]
In recent years, for the purpose of safe use of city gas and LP gas, the amount of use of these gases has been measured, and when the amount of use has increased abnormally, or has been used for a time far from normal use conditions. When it is detected that the gas passage is detected, a security device that blocks the gas passage is in widespread use.
[0003]
This type of security device takes the gas flow rate detection signal into the safety control circuit, processes it with an internal microcomputer, monitors the gas flow rate, outputs a shutoff signal if there is an abnormality, and closes the shutoff valve. It is configured.
[0004]
The gas flow rate is detected by detecting the flow rate of the gas through the measurement chamber with a predetermined volume and the gas flow velocity of the gas flow path with a predetermined cross-sectional area using the ultrasonic propagation time. There is an ultrasonic type that measures a flow rate by processing a signal. The principle of ultrasonic flow rate detection is that the propagation time of the ultrasonic wave between two points in the gas passage is a function including the gas flow velocity. By measuring the propagation time, the gas flow velocity can be calculated backward, and if the flow velocity is known, it passes. It applies that the flow rate is known from the cross-sectional area.
[0005]
[Problems to be solved by the invention]
By the way, the conventional gas security device has the following problems.
[0006]
Because city gas and LP gas generate different amounts of heat per unit volume, the city gas and LP gas have a difference in their weighting when detecting the gas flow rate so that the same security operation can be obtained at the same heat consumption point. They are divided into city gas meters and LP gas meters. Therefore, if the LP gas meter is mistakenly installed in the city gas supply path or the city gas meter is mistakenly installed in the LP gas supply path, there is a problem that safety cannot be secured.
[0007]
In addition, propane gas is the main component of LP gas, but due to differences in raw materials and refining accuracy, high and low molecular weight gas may be mixed in, resulting in differences in gas quality. There is also a problem in that there is a difference in the reliability of security when using.
[0008]
In view of the above-described conventional problems, an object of the present invention is to provide a gas security device that detects and displays a gas type.
[0009]
[Means for Solving the Problems]
The gas safety device of the present invention is a gas gas safety device installed in a city gas supply channel or an LP gas gas security device installed in an LP gas supply channel. A control measurement circuit that emits ultrasonic waves on one of the pair of ultrasonic sensors and receives ultrasonic waves on the other side to measure the propagation time of the ultrasonic waves, and a propagation time A flow rate calculation is performed using the measurement results as data, and a safety control circuit that drives a shutoff valve that shuts off the gas passage when abnormal use is detected, and a gas type display section that determines and displays the gas type using the propagation time measurement results as data. Since the propagation time differs depending on the sound speed specific to each gas type, the gas type can be detected and displayed.
[0010]
In addition, when gas is used, the velocity component is added to the sound speed inherent to the gas type and the propagation time is not constant. Therefore, the gas type display unit measures the propagation time in two directions, positive and negative, with respect to the gas passage direction. The measurement accuracy is improved by using the propagation time data when the time difference becomes zero, that is , using the propagation time data of the ultrasonic wave when the gas flow rate is judged to be zero. Can do.
[0011]
In addition, the gas type display unit determines ultrasonic propagation time data using a predetermined propagation time determined by the installation conditions of the gas passage and the ultrasonic sensor as a threshold value, and displays the gas type, or the gas molecular weight The gas molecular weight can be detected by ultrasonic propagation time data using the correlation of the propagation time, and the gas type can be displayed by an indicator configured to display differently depending on the propagation time data.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a gas security device of the present invention will be described with reference to FIGS. 1 and 2.
[0013]
In FIG. 1, reference numeral 1 denotes a control measurement circuit which outputs an electrical signal for ultrasonic transmission from its transmission output terminal OUT toward the ultrasonic sensor 2 (2A) for transmission. The transmitting ultrasonic sensor 2 </ b> A acoustically converts an electrical signal and emits an ultrasonic wave in the gas passage 3. In the gas passage 3, a receiving ultrasonic sensor 2 (2 </ b> B) is installed at a distance L from the transmitting ultrasonic sensor 2 </ b> A, and ultrasonic waves propagated in the gas passage 3 are taken. The reception ultrasonic sensor 2 </ b> B converts the captured ultrasonic wave again into an electric signal and inputs it to the reception input terminal IN of the control measurement circuit 1.
[0014]
The control measurement circuit 1 measures the time from the transmission output to the reception input, that is, the propagation time T of the ultrasonic wave at the distance L in the gas passage 3, and uses the measurement data signal T-DATA as the gas type display unit 4 and the security control circuit 5. Output to.
[0015]
The gas type display unit 4 determines the measurement data signal T-DATA by using the predetermined propagation time for each gas type determined by the installation conditions of the gas passage 3 and the ultrasonic sensor 2 (2A, 2B) as a threshold value. The difference between gas and LP gas is detected and displayed.
[0016]
The safety control circuit 5 takes in the measurement data signal T-DATA and calculates the flow rate. When the usage amount increases abnormally or when it is detected that it is used for a time far from the normal use state, the safety control circuit 5 To cut off the gas passage 3.
[0017]
The connection state of the output terminal OUT and the input terminal IN of the control measurement circuit 1 and the ultrasonic sensor 2 (2A, 2B) is configured to be switchable by the switching means 7. And by switching the connection relationship with this switching means 7, the propagation time is measured in two directions positive and negative with respect to the gas passage direction, and when there is no difference in the propagation time, it is determined as zero flow rate, The propagation time T at that time is used as data for determining the gas type, thereby improving the measurement accuracy.
[0018]
The gas type display is not limited to two types of city gas and LP gas. If two threshold values are set, LP gas, air, and city gas can be distinguished. Here, the detection of air is used as a display to warn of a gas non-supply state when the gas meter is initially installed.
[0019]
Moreover, the indicator 8 which has several LED8a-8e which displays the gas molecular weight of a structure as shown in detail in FIG. 2 is provided in the gas type display part 4 of this embodiment. The measurement data signal T-DATA is connected to the decoder 9. When the mixing ratio of butane gas having a large molecular weight is high, the corresponding molecular weight increases. Conversely, when the mixing ratio of methane gas having a low molecular weight is high, the corresponding molecular weight decreases. Since the gas molecular weight and the ultrasonic wave propagation speed are inversely proportional, the connection between the output terminal of the decoder 9 and the LEDs 8a to 8e of the indicator 8 is propagated to the LED 8a on the methane side with the shorter propagation time. The longer one is connected to the LED 8e on the butane side. Thereby, the composition tendency of the gas currently in use can be displayed, and can be used as a warning display of gas quality. The display method of the indicator 8 is not limited to the display using a plurality of LEDs as described above.
[0020]
【The invention's effect】
According to the gas safety device of the present invention, as is apparent from the above description , in the gas safety device for city gas installed in the city gas supply path or the gas security device for LP gas installed in the LP gas supply path, since the display on the gas type display unit out, can also be found an error easily and quickly when placed incorrectly meter does not conform to the gas species, it is possible to appropriate treatment, safety of the original gas safety device The security function by the control circuit is ensured.
[0021]
Further, the measurement accuracy can be improved by configuring the gas type display unit to use ultrasonic propagation time data at the time of determining the gas flow rate to zero.
[0022]
Further, when the gas molecular weight is displayed on the indicator, it is possible to detect in advance even when a low quality gas is supplied, and the effect of being easy to cope with is exhibited.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of a gas security device of the present invention.
FIG. 2 is a configuration diagram of an indicator in the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Control measurement circuit 2 (2A, 2B) Ultrasonic sensor 3 Gas passage 3 Ultrasonic sensor drive circuit 4 Gas type display part 8 Indicator

Claims (3)

In a city gas gas safety device installed in a city gas supply channel or an LP gas gas security device installed in an LP gas supply channel, a gas passage and a pair or more installed at an appropriate distance in the gas passage Control measurement circuit that emits ultrasonic waves on one of the ultrasonic sensors and the ultrasonic sensor on the other side and receives ultrasonic waves on the other side to measure the propagation time of ultrasonic waves, and the flow rate calculation using the propagation time measurement results as data And a safety control circuit that drives a shut-off valve that shuts off the gas passage when abnormal use is detected, and a gas type display unit that determines and displays the gas type using the propagation time measurement result as data . It is characterized in that the propagation time is measured in two directions positive and negative with respect to the gas passage direction, and the judgment display of the gas type is performed using the propagation time when the difference between the propagation times becomes zero. Gas security device. The gas type display unit determines ultrasonic propagation time data using a predetermined propagation time determined by the installation conditions of the gas passage and the ultrasonic sensor as a threshold value, and displays the type of gas. The gas security device according to 1. The gas type display unit detects the gas molecular weight from the ultrasonic propagation time data using the correlation between the gas molecular weight and the propagation time, and displays the gas type with an indicator configured to vary the display according to the propagation time data. The gas security device according to claim 1 or 2, wherein the gas safety device is configured to perform the above.

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