JPS6030409B2 - gas safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas safety device, and more particularly to a gas safety device capable of preventing gas leakage from gas piping such as a rubber hose.

Conventionally, as this type of device, a gas leak alarm that detects leaked raw gas is known.

However, this gas leak alarm is often influenced by external factors such as wind and gas specific gravity, and is not reliable enough as a safety device. Therefore, as shown in the example in Fig. 1, a pressure switch 3 operated by a diaphragm is interposed between the gas valve 1 and the combustion appliance 5, and when the residual gas pressure decreases mainly due to damage or poor connection of the rubber hose 4, the pressure switch 3 An attempt was made to detect gas leaks by turning off the gas. However, according to the results of actual tests, this method is not practical because the residual gas pressure gradually decreases due to temperature changes, and in the case of new rubber hoses, the gas pressure decreases due to gas absorption by the rubber hose. This can be explained with reference to Figure 2, where the axis is time and the vertical axis is residual gas pressure. Normally, when the gas plug 1 is closed after combustion, the residual gas pressure will change as shown by the solid line △PI due to the temperature drop. only decreases. Since this △PI is not due to gas leakage, △PI
The setting must be made so that the pressure switch 3 turns OFF when the pressure drop is greater than △P2.If △PI<△P2, the difference between the residual gas pressure and the atmospheric pressure will increase at night after heating in a cold region. There may be no significant difference between the two, and it may become impossible to determine whether the detection by the switch 3 is due to gas leakage or temperature change. It is also clear that the larger △P2 is, the worse the detection ability for minute gas leaks is, and the slower the detection response time becomes. If the gas valve 1 is opened again, the gas pressure will rise and no gas leak will be detected. Therefore, when a gas leak occurs in a gas pipe, the present invention can be reliably detected at a point where the pressure drop is smaller than △PI. The purpose of the present invention is to provide a gas safety device that can discriminate and detect even the slightest gas leak by comparing the residual gas pressure with the pressure drop per unit time.

Hereinafter, the present invention will be explained in detail based on the embodiments shown in FIGS. 3 to 6.

Reference numeral 6a denotes a fixed pipe made of a metal pipe, and on the upstream side of the fixed pipe 6a, near the gas supply source, there is a solenoid valve 8 that operates only when energized, and on the downstream side there is a gas pressure detection device 9. will be arranged.

It is desirable to place the solenoid valve 8 and the gas pressure detection device 9 as close to the gas supply source as possible; for example, in the case of propane gas, they are installed immediately after the gas cylinder, and in the case of city gas, they are both installed outdoors, immediately after the flow meter. It's good to do that. In addition,
As the gas pressure detector 9, one that detects gas pressure as an electrical value such as an amount of current is used. The downstream side of the fixed pipe 6a is branched to a desired position indoors, and the gas appliance 5 is connected to the tip of the branch via a flexible hose 6b.

Usually, a gas stopper is placed at the branch end of the fixed pipe 6a, and the flexible hose 6b is connected to this gas stopper, and of course a gas stopper may be used in the present invention.
In the present invention, this gas valve is always left open, so illustration and explanation are omitted. The gas appliance 5 is provided with a switch 10 that opens and closes in conjunction with the opening and closing of the appliance tap 7 of the gas appliance 5, and a flame sensing element 11 that detects the presence or absence of combustion as the opening and closing of an electric circuit.

The switch 10 and the flame sensing element 11 are connected to the amplifier 12.
This amplifier 12 outputs an electric signal indicating whether the appliance tap 7 is open or not, and an electric signal indicating whether there is combustion when the appliance tap 7 is opened. It has become. The gas pressure detection device 9 and the amplifier 12
are connected to a control panel 13, and future detection signals are combined and organized in the control panel 13 so that the opening/closing of the energizing circuit to the solenoid valve 8 is controlled.

The control panel 13 has a circuit configuration shown in FIG.
Reference numeral 14 denotes an abnormality signal receiving circuit. If combustion is not detected from the amplifier 12 even though the appliance stopper 7 is open, an abnormality signal is inputted. When this abnormality signal is input, a signal is sent to the electromagnetic valve power supply circuit 21 described later. It is set to be sent. It should be noted that this abnormal signal receiving circuit 14 houses a timer function, so that the signal is not output within a predetermined time (5 seconds in the embodiment), and normally after the appliance tap 7 is opened. The time delay from ignition to the time when the flame susceptor 11 detects combustion can be absorbed. Reference numeral 15 denotes an appliance stopper signal receiving circuit, which outputs a signal to the supply gas pressure monitoring circuit 18 and the closing gas pressure monitoring circuit 19 in response to an input signal from the amplifier 12 indicating that the appliance stopper 7 has been opened.

Reference numeral 16 denotes a gas pressure detection signal receiving circuit which receives an input signal from the gas pressure detection device 9 and outputs a gas pressure signal to the supply gas pressure monitoring circuit 18 and the closing gas pressure monitoring circuit 19.

Reference numeral 17 denotes a power supply circuit, which is connected to supply power to each circuit in FIG.

Reference numeral 18 denotes a supply gas pressure monitoring circuit, which outputs an output to the electromagnetic valve power supply circuit 21 when the appliance tap 7 is opened based on input signals from the appliance tap signal receiving circuit 15 and the gas pressure detection signal receiving circuit 16, indicating that the appliance tap 7 is not connected. However, if the gas pressure suddenly drops due to a hose coming loose, etc., the output will be stopped.

Reference numeral 19 denotes a closed gas pressure monitoring circuit, which is constructed as shown in FIG.

The input signal from the gas pressure detection signal receiving circuit 16 is converted into a frequency by a U-F converter 24 and counted by a counter.
It is output to the storage circuit 26 and the comparison circuit 29. On the other hand, the input signal from the instrument signal receiving circuit 15 is connected to each circuit through the setting circuit 25, so that when the instrument stopper 7 is closed, the closing gas pressure monitoring circuit 19 is set. 27 is a reset circuit, 28 is a timer circuit, and this closing gas pressure monitoring circuit 19 operates a timer circuit 28 when the appliance tap 7 is closed, and at the same time stores the gas pressure at that point in a memory circuit 26. . After a certain period of time (3 minutes in the example) set by the timer circuit 28, the comparison circuit 29 compares the stored gas pressure with the actual gas pressure.
When the gas pressure drop exceeds a certain value (in the example, one dish hmH20), the memory circuit 22 of the control panel 13 (
(see Figure 4).

If the gas pressure drop is within a certain value, a reset signal is sent to the memory circuit 26 and the timer circuit 28 to reset each, and then the timer circuit 28 is activated so that the operation of memorizing the gas pressure at that point is repeated. It has become.
Reference numeral 22 denotes a memory circuit, which, when receiving the above-mentioned lock signal, stores it until a reset signal is sent from a reset button (not shown) or by turning the power off and on again, and then activates the solenoid valve power supply circuit 21. It remains locked and activates the alarm circuit's buzzer, lamp, etc.

The electromagnetic valve power supply circuit 21 receives signals from the abnormal signal receiving circuit I4, the supply gas pressure monitoring circuit 18, and the memory circuit 22,
When there is an input signal from the supply gas pressure monitoring circuit 18, the solenoid valve 8 is energized; If so, the energization to the solenoid valve 8 is stopped.

In addition, a pulse signal is sent to the input end 32 of the closing gas pressure monitoring circuit and the alarm circuit 23 by the two-way clock circuit.

However, when the device of the present invention is turned on, the solenoid valve 8 is normally closed and gas is not supplied indoors, but when one of the appliance taps 7 is opened without using gas, the solenoid valve 8 is energized. gas is supplied.

Then, while the appliance plug 7 is opened and combustion is occurring, the electricity to the solenoid valve 8 is maintained, and gas is supplied and kneaded, but the gas is turned off or even if the appliance tap 7 is opened, there is no combustion and the set time (5 seconds) elapses. When the temperature exceeds the limit, an abnormality signal is output, and the energization to the solenoid valve 8 is stopped, thereby preventing raw gas from leaking. Also, after using the gas, when all the appliance taps 7 are closed, the solenoid valve 8 is closed.
The residual gas pressure in the piping on the downstream side of the solenoid valve 8 is monitored by the gas pressure detection device 9, and if the change in the residual gas pressure exceeds a certain time (10 skin mH20) per unit time (3 minutes), gas leaks. The solenoid valve power supply circuit 21 is electrically locked, the alarm circuit 23 issues an alarm, and the piping is inspected.

Gas leakage from this piping is detected per unit time, so minute pressure changes can be used effectively.This is explained using Figure 6, where the horizontal axis is time and the vertical axis is gas pressure. . T2 - T3 = T4 - T5 = 3 minutes is the unit time of this example, and it is assumed that a pressure change of △P4 may occur due to temperature change between T3 and T2, and at T5, gas leaks and the pressure decreases in a chain line pattern. Assume that the pressure has changed by ΔP3 by the time T4. Then, if ΔP4>ΔP3, it can be determined that there is a gas leak. Actual measurements show that the change in residual gas pressure is 37 mmH20 per 100, and it is a fact that a change in gas pressure equivalent to a gas leak due to a sudden temperature change does not occur even in everyday life in a cold region within a rectangular time of about 3 minutes. Therefore, △P3 may be sufficiently smaller than △PI by 4.
Therefore, even if the residual gas pressure becomes equal to, for example, atmospheric pressure due to ΔPI due to reasons other than piping defects, the present device can detect gas leakage.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams of the conventional example, Figure 3 is an overall side view of the device of the present invention, Figure 4 is a control panel block wiring diagram, and Figure 5 is a block diagram of the closed gas pressure monitoring circuit in the control panel. Wiring diagram, 6th
The figure is an explanatory diagram of the detection principle of this device. 5...Gas appliances, 6a...Fixed piping,
6b...Flexible hose, 7...
Appliance stopper, 8...Solenoid valve, 9...Gas pressure detection device, 10...Switch, 11...
・Fuel sensing element, 12...Amplifier, 13...
control panel. Spear figure O2. Figure 3, figure 6, figure 4, figure 5, figure 5.

Claims (1)

[Claims] 1. A solenoid valve is placed near the gas supply source side of the gas piping, and the solenoid valve is energized to supply gas only when gas is normally used. A gas pressure detection unit is arranged to memorize the gas pressure when the solenoid valve is closed, and then compare the gas pressure after a predetermined period of time with the stored gas pressure, and to issue an alarm if the gas pressure drop exceeds a certain level. It notifies and prevents leakage after the solenoid valve by emitting a signal or locking the energizing circuit to the solenoid valve, and if the gas pressure drop is below a predetermined value, the gas pressure is re-memorized and the gas pressure is restored after a pre-determined time from re-memory. A gas safety device that repeatedly compares the following: