JPH0222850B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a gas cutoff device for preventing explosion accidents, poisoning accidents, etc. caused by city gas, propane gas, etc. Conventional configuration and its problems Many gas accidents are caused by abnormal outflow of unburned gas. This type of abnormal leakage occurs when the gas hose that connects the gas pipe and gas appliance is disconnected, cracked, cut, or
This can be caused by a variety of causes, including a lack of oxygen due to long-term use of gas appliances, equipment falling over due to earthquakes, etc., and misfires. Conventionally, in response to this kind of abnormal outflow of unburned gas, it has been proposed to use a gas alarm to detect the outflow and issue an alarm, or to use a fuzukotsukku. However, in the case of the former, since it merely issues a warning, if it is impossible to close the gas chamber, such as when no one is present, the abnormal outflow of unburned gas will continue, which is dangerous. In the latter case, if the unburned gas flows out to such an extent that the fuse of the fuel tank does not operate, the outflow will continue. Purpose of the Invention The present invention was invented in view of the shortcomings of such conventional devices, and it detects the flow rate of gas and determines whether or not the detected flow rate has become dangerous from the time when it is flowing. The gas flow path is determined according to predetermined processing procedures, and if it is determined that the situation is dangerous, the gas flow path is shut off using a shutoff means installed in the gas flow path, thereby preventing an explosion. The object of the present invention is to provide a gas cutoff device that can prevent accidents. Structure of the Invention In order to achieve the above object, the present invention includes a gas flow rate sensor attached to a gas meter and a signal from the sensor as input, and processes these input signals according to a predetermined processing procedure. A control unit that determines whether or not gas can be shut off and outputs a shut-off signal when determining the shut-off, and a shut-off means that shuts off the gas flow path in response to the shut-off signal from the control unit, and the control unit is configured to It is equipped with a code switch as a meter type selection means, and an arithmetic processing means for determining whether or not to shut off based on the signals from the flow rate sensor and the code switch. DESCRIPTION OF EMBODIMENTS FIG. 1 is a schematic diagram of a gas cutoff device according to an embodiment of the present invention. Gas meter 1 and flow sensor 2
Install. The flow rate sensor 2 is composed of, for example, a magnet provided on a diaphragm in a gas meter, and a magnetic field detector such as a reed switch that responds to the magnet that moves with the movement of the diaphragm. In addition to the diaphragm, the magnet may be provided in a part of a link mechanism that transmits the reciprocating motion of the diaphragm to a valve part that opens and closes a metering chamber, or in a meter indicating part. The reed switch turns on and off each time the diaphragm moves back and forth. Amount of gas passing through the meter in one round trip of the diaphragm ql
Since the reed switch is fixed, the amount of gas passing through the meter per unit time can be measured by measuring the time from when the reed switch is turned on until it is turned on again. A signal from the flow rate sensor 2 is input to the control section 3. The control unit 3 measures the amount of gas passing through the meter per unit time using the above-mentioned means, for example, and determines whether or not there is a dangerous state based on the gas amount according to a predetermined processing procedure. If it is determined that this is the case, a cutoff signal is output. For example, the cutoff conditions for determining whether or not a situation is dangerous are as follows. It is determined whether the measured amount of gas has flowed at a constant value for a predetermined time or longer, and if it is within the predetermined time, it is determined to be safe, and if it is longer than the predetermined time, it is determined to be dangerous. This predetermined time is set to be longer than the time during which a gas appliance corresponding to the flow rate will actually be continuously used, and to a time that will not cause an explosion even if it is released as unburned gas. Accordingly,
According to the logic described above, if the same appliance is used for an impossibly long time, it is determined that unburned gas is leaking out for some reason, and a shutoff signal is output. This cutoff signal drives a cutoff means 4, such as a solenoid valve, provided in the gas flow path to cut off the gas flow path. FIG. 2 is a block diagram showing the control section of FIG. 1 in more detail. A signal from the flow rate sensor 2 is input to a microcomputer 5 as a calculation processing means. Signals from a switch 6 for selecting the type of gas and a switch 7 for selecting the type of gas meter are also input to the microcomputer. Since the amount of unburned gas sufficient to cause an explosion differs depending on the type of gas, it is necessary to change the predetermined time, that is, the cutoff condition, when determining the danger from the amount passing through the gas meter, depending on the type of gas. Furthermore, since the amount of gas that passes through the meter by one round trip of the diaphragm of the gas meter varies depending on the type of meter, it is necessary to input the type of meter into the microcomputer 5 in order to measure the amount of gas passing through the meter. The microcomputer 5 measures the amount of gas passing through the meter based on the processing procedure stored in its ROM part as a program, the gas type and meter type input from the switches 6 and 7, and the flow rate signal input from the flow rate sensor 2. At the same time, the risk is determined. If it is determined that the valve is shut off, a shut-off signal is output to the coil 4C of the electromagnetic valve as a shut-off means. The switches 6 and 7 serving as gas type and meter type selection means require the input of (number of gas types M)+(number of meter types N) to the microcomputer 5. These are not always used independently;
Used in combination by selecting one gas type and one meter type. Therefore, by coding all of these possible combinations and inputting this code into the microcomputer 5, the number of inputs can be reduced. For example, if the gas type is 3 and the meter type is 5, there are 15 combinations as shown in the table. If this is expressed in binary code, it can be expressed in 4 bits as shown in this table.

[Table] If the number of bits is B, the possible combinations are 2 ^B
That's right. Conversely, if the number of combinations to be input is L, the required number of inputs, that is, the required number of bits B _N is
It is log2L. In the above example, L is 15,
The required number of bits B _N is 4. In this way, by using a code switch that encodes the combination and outputs the corresponding code to the microcomputer according to the selected combination of gas type and meter type, only the code switch 8 can be used as shown in Fig. 3. In this way, the required gas type and meter type can be selected, and the number of inputs to the microcomputer 5 can be halved from 8 in the above example to 4. In addition, since selection can be made using only the switch 8, the control section can be downsized, which allows the entire device to be downsized. Furthermore, in the example shown in FIG. However, by using the code switch 8 shown in Figure 3, you will not be able to select multiple combinations or not select at all, and this kind of operation will not occur. Eliminate mistakes. Effects of the Invention According to the present invention, a control unit processes a flow rate signal from a flow rate sensor provided in a gas meter using a selection signal from a gas type/meter type selection means, and determines whether or not to shut off a gas flow path. When the cutoff is determined, the cutoff output is output to the cutoff means provided in the gas flow path, and since a code switch is used as the gas type/meter type selection means, the following effects can be obtained. First, it is possible to obtain an extremely versatile gas cutoff device that can be used with a wide variety of gas types and meter types. Second, by using a code switch as the gas type/meter type selection means, various selection operation errors can be prevented and the device can be downsized.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a gas cutoff device according to an embodiment of the present invention, Fig. 2 is a block diagram of a control section of the same device, and Fig. 3 is a block diagram of a control section according to an embodiment of the present invention. . 1...Gas meter, 2...Flow rate sensor, 3...
Control unit, 4... Cutoff means, 5... Microcomputer as arithmetic processing means, 8... Code switch.

Claims (1)

[Claims] 1. A flow rate sensor attached to a gas meter that detects the gas flow rate, and a signal from this sensor as input, processes this input signal according to a predetermined processing procedure, and determines whether the gas can be shut off. It consists of a control section that outputs a cutoff signal when a cutoff is determined, and a cutoff means that cuts off the gas flow path in response to the cutoff signal from the control section, and the control section includes a code switch as a gas type/meter type selection means. , calculates the amount of gas passing through the meter based on the meter type signal of the gas type/meter type signal from the code switch and the signal from the flow rate sensor, sets the cutoff condition based on the gas type signal, and calculates the amount of gas passing through the meter and the cutoff. A gas shutoff device that includes a calculation processing means that determines whether or not to shut off based on conditions.