JPH0239120Y2 - - Google Patents

Description

[Detailed description of the invention] 〓Field of industrial application〓 The present invention relates to an improvement of a gas safety device.

〓Prior art〓 The present applicant previously proposed a gas safety device as Japanese Patent Publication No. 15829/1983.

This gas safety device has a solenoid valve 2 disposed at an upstream portion of a gas supply path 1 to open and close gas supply to the downstream side of the gas supply path 1, and a solenoid valve 2 that opens and closes gas supply to the downstream side of the gas supply path 1. A pressure switch 3 is provided which issues a pressure reduction signal when the gas pressure falls below a predetermined value, and a manual switch 5 which issues a gas usage start signal when gas usage starts, and signals from the manual switch 5 and the pressure switch 3 are provided. A control panel 6 for controlling the opening and closing of the electromagnetic valve 2 is arranged, and the control panel 6 has the following functions.

<Solenoid valve opening/closing function> When a gas use signal is input from the manual switch 5, the solenoid valve 2 is opened, and the solenoid valve 2 is closed when the input of the gas use signal disappears and by each function described later.

<Abnormal shutoff function> When an abnormal signal is input from an abnormality detector such as a seismic sensor or gas leak alarm, the solenoid valve 2 is closed and an alarm is issued.

<Pre-use inspection function> A gas usage signal is input from the manual switch 5, and after a predetermined time set by a relatively short timer, the pressure switch 3 (the first pressure switch 3a of the present application does not exist in the conventional example, and the first pressure switch 3a of the present application does not exist). Corresponding to the second pressure switch), when a pressure drop signal is input from the second pressure switch, the solenoid valve 2 is closed and an alarm is issued.

<Post-use inspection function> The solenoid valve 2 is closed when a pressure drop signal is input within a predetermined time set by another relatively long timer after the gas usage signal is no longer input from the manual switch 5. Continue to issue a warning.

〓Problems to be solved by the invention〓 However, the above-mentioned conventional gas safety device does not work properly in the event of an abnormality, commonly called an overflow, in which a large amount of gas leaks out at once, such as when a rubber hose falls off while gas is being used. The leaked raw gas must be detected by a gas leak alarm and the solenoid valve 2 must be closed, which may cause a delay in response and create a dangerous situation.

Therefore, as a result of repeated intensive research and testing,
Although it is possible to detect this overflow with the pressure switch, the drop in gas pressure due to overflow when one rubber hose falls off is usually 280 mm/
In the case of household propane gas supplied as H ₂ O, it is as small as 80 mm/H ₂ O, and it has been found that if a pressure drop signal is output at this level, the post-use inspection function does not function satisfactorily. In other words, this after-use inspection is to check the piping based on the drop in closing gas pressure after closing the solenoid valve 2, but if gas use is stopped after heating with a gas stove, the temperature may drop due to the heating being stopped. This closing gas pressure also decreases. This drop in gas pressure due to temperature change is not only normal, but also a large pressure drop of about 150 mm/H ₂ O can be observed with a temperature change of several degrees, although it depends on the volume of the pipe. Therefore, 80% after using gas.
When the pressure decreases on the order of mm/H ₂ O, it may not be possible to accurately determine whether the decrease is due to a leak or a temperature change.

Therefore, the present invention was devised to solve the above-mentioned drawbacks, and its purpose is to provide a gas safety device that can quickly and reliably detect excessive flows and also has a satisfactory post-use inspection function. It is.

〓Means for solving the problems〓 In line with the above-mentioned purpose, the configuration of the present invention, which is summarized in the above-mentioned utility model registration claims, is to solve the above-mentioned problems by providing a solution to the upstream part of the gas supply path 1. A solenoid valve 2 that opens and closes the gas supply to the downstream side of the gas supply path 1
A pressure switch 3 is disposed in the gas supply path 1 downstream of the electromagnetic valve 2, and a pressure switch 3 is disposed to issue a pressure drop signal when the gas pressure falls below a predetermined value. a manual switch 5 that generates a signal, the manual switch 5 and the pressure switch 3;
A gas safety device comprising a control panel 6 that controls the opening and closing of the solenoid valve 2 based on signals from a source,
The pressure switch 3 is replaced by a first pressure switch 3a which issues a pressure reduction signal when the gas pressure becomes less than a predetermined value.
and a second pressure switch 3b that issues a pressure drop signal when the gas pressure drops further below this predetermined value, and the first pressure switch 3a is turned on when the manual switch 5 issues a gas usage start signal. The series set of the first pressure switch 3a and the interlocking switch 5a and the second pressure switch 3b are connected in parallel through the interlocking switch 5a, and when gas is used, the first pressure switch 3a lowers the gas pressure. A technical measure has been taken in which an overflow signal indicating a large drop in gas pressure is transmitted to the control panel 6 by the second pressure switch 3b after gas use is finished, and a pipe leak signal indicating a large drop in gas pressure is transmitted to the control panel 6. It is something.

〓Operation〓 Therefore, it goes without saying that the gas safety device of the present invention has the same function as the conventional one described above if the conventional one is used as the control panel 6, but the gas safety device of the present invention has the same function as the conventional one described above. When the gas use start signal is issued to the control panel 6, the interlock switch 5a is turned on, so that while gas is in use, the signal from the first pressure switch 3a connected in series to the interlock switch 5a is sent to the control panel 6. The solenoid valve 2 is closed by detecting an overflow, which is a small pressure drop.

After using the gas, operate the manual switch 5 to cut off the input of the gas use start signal to the control panel 6, the interlock switch 5a will turn OFF, and the second pressure switch 3b will prevent a large drop in gas pressure over a relatively long period of time. It sends a pipe leakage signal that takes into account certain temperature effects to the control panel 6 and acts to keep the solenoid valve 2 closed.

〓Example〓 Next, an example of the present invention will be described below with reference to Figs. 1 to 3. .

In the figure, 1 is a gas supply line, which is usually called a fixed pipe, and one end (on the left side of the figure) is connected to a gas supply source (not shown), such as a gas cylinder in the case of propane gas.
In the case of city gas, it is connected to the gas meter outlet. On the other hand, the other end of the gas supply path is appropriately branched to provide gas plugs 7, 7, and gas appliances 4, 4 are connected to these gas plugs 7, 7 via flexible hoses 8, 8 such as rubber hoses. A supply system is configured. Note that this gas supply system is the same as the conventionally known system.

An electromagnetic valve 2 for opening and closing the gas supply to the downstream side of the gas supply path 1 is disposed upstream of the gas supply path 1 . In this embodiment, the solenoid valve 2 uses a conventionally known type that closes the valve by pulling up the valve body when energized and shutting off the energization. However, if the valve is closed by attracting and holding it with a permanent magnet, a magnet that generates a demagnetizing force that cancels out the magnetic force of the permanent magnet may be used. In addition, when using this permanent magnet holding type solenoid valve, it is necessary to change the configuration of the solenoid valve power supply circuit 19, which will be described later, but since the configuration is conventionally known, illustration and description thereof will be omitted.

Further, a pressure switch 3 is disposed in the gas supply path 1 downstream of the electromagnetic valve 2 to issue a pressure reduction signal when the gas pressure falls below a predetermined value. As shown most clearly in FIG. 2, this pressure switch 3 has a rod 102 erected on a diaphragm 101 whose one side faces the gas supply path 1, and a permanent magnet 103 is disposed at the top of the rod 102 to prevent gas flow. The diaphragm 101 to the permanent magnet 10 due to the gas pressure fluctuation in the supply path 1
3 to move up and down, and furthermore, the permanent magnet 1 is attached to a fixed portion such as the diaphragm cover 104.
The first pressure switch 3a and the second pressure switch 3 are composed of a reed switch that turns on when 03 approaches.
b are placed side by side in the vertical direction. That is, this pressure switch 3 is a first pressure switch 3 that turns on when the gas pressure falls below a predetermined value and issues a pressure drop signal.
a, and a second switch 3b which turns on and issues a pressure drop signal when the gas pressure drops further below this predetermined value.

Furthermore, an appropriate place such as near the gas appliances 4, 4,
For example, on a wall near the most frequently used gas appliance 4, there is a manual switch 5 that is turned on when gas is used and turned off when gas is finished, and a solenoid valve that is activated by a signal from this manual switch 5 and the pressure switch 3. 2 and a control panel 6 for opening and closing. Although the manual switch 5 is not clearly shown, it is turned on when the button 8a is pressed and turned off when the button 8b is pressed.
Furthermore, although the manual switch 5 is shown in the figure at a location separate from the control panel 6, it goes without saying that it may be housed within the housing of the control panel 6.

The control panel 6 is constructed as clearly shown in FIG. 3, and includes a switch signal processing circuit 15 that uses a timer consisting of a combination of a resistor and a capacitor, a logic circuit, and a transistor, and a pressure switch signal processing circuit. 16, a prohibition circuit 17, an alarm display circuit 18, and a solenoid valve power supply circuit 19.

The switch signal processing circuit 15 includes a start signal circuit C2 which outputs a control signal to the solenoid valve power supply circuit 19 when a gas usage signal is input from the manual switch 5.
At the time of starting, a control signal is output to the solenoid valve power supply circuit 19 and the alarm display circuit 18 if a pressure drop signal is input from the pressure switch 3 after a predetermined time after the gas use signal is input via the timer. A control signal is output to the inhibition circuit 17 when a pressure drop signal from the pressure switch 3 is input within a predetermined time after the gas usage signal is no longer input via the gas leak signal circuit C3 and another timer. It consists of a rear gas leak signal circuit C4. In addition, starting signal circuit C
2 detects the start of gas use by a predetermined input voltage drop when the manual switch 5 is turned on, and this gas use start signal is inverted by the NOT circuit 64 and outputs a control signal to the solenoid valve power supply circuit 19. It is something. In addition, gas leakage signal circuit C3 at startup
is connected to the output terminal of the NOT circuit 64 through a timer made up of a combination of a resistor 65 and a capacitor 66, which delays the signal for a predetermined period of time (for example, 1 second).
Connected to one input end of the NAND circuit 67, this
The output terminal of the pressure switch signal processing circuit 16 is connected to the other input terminal of the NAND circuit 67, and
The output of the NAND circuit 67 is inverted by a NOT circuit 68. Furthermore, the gas leak signal circuit C4 after use connects the input end of the NOT circuit 64 to one input end of the NAND circuit 73, and the other input end of the NAND circuit 73 is connected to the pressure switch signal processing circuit 16. Connect the output ends, and
The input end of the NOT circuit 64 is made up of a combination of a resistor 70 and a capacitor 71, and is connected to one input end of the NAND circuit 75 via a timer and a NOT circuit 72 that delay the signal by a predetermined period of time (for example, 3 minutes). The output terminal of the NAND circuit 73 is the NOT circuit 7
4 to the other input terminal of the NAND circuit 75.

When a pressure drop signal is input from the pressure switch 3, the pressure switch signal processing circuit 16 transmits the pressure drop signal to the switch signal processing circuit 1 as described above.
5 and also outputs a control signal to the alarm display circuit 18. This pressure signal circuit C5 detects a pressure drop when a predetermined input voltage drops when the first pressure switch 3a or the second pressure switch 3b is turned on, and this pressure drop signal is inverted by the NOT circuit 76. ing.

The prohibition circuit 17 is a lock signal circuit that stores the control signal input from the gas leakage signal circuit C4 after use until it receives a return signal, and outputs the control signal to the solenoid valve power supply circuit 19 and the alarm display circuit 18. C6 and an alarm display signal circuit C7. The lock signal circuit C6 and the alarm display signal circuit C7 are comprised of a flip-flop circuit 77 whose input terminal on one side is connected to the gas leak signal circuit C4 after use, and whose input terminal on the other side is connected to a power supply. The normal high level output terminal is a lock signal circuit C6, and the normal low level output terminal is an alarm display signal circuit C7.

The alarm display circuit 18 is an alarm display signal circuit C.
7 and the pressure signal circuit C5, an indicator lamp energization signal circuit C8 outputs a control signal for energizing the indicator lamp 21, and an alarm display signal circuit C7 and a gas leakage signal circuit C3 at the time of starting. It consists of a buzzer energization signal circuit C9 which outputs a control signal for energizing the buzzer 20 when receiving a control signal from one of them. The indicator light energization signal circuit C8 includes an AND circuit 78 in which an alarm display signal circuit C7 is connected to an input terminal on one side, an output terminal of a transmitting circuit 88 is connected to an input terminal on the other side, and a lock signal circuit C6 is connected to an input terminal on one side. It has an AND circuit 79 connected to the pressure signal circuit C5 at its input end, the output ends of both AND circuits 78 and 79 are connected to the input end of an OR circuit 80, and the output end of this OR circuit 80 is connected to the indicator light 21. The base of the transistor 83 is connected to the base of the transistor 83, which switches on and off the current supply. The buzzer energization signal circuit C9 also connects the alarm display signal circuit C7 and the starting gas leakage signal circuit C3 to one input terminal, and connects the transmission circuit 88 to the other input terminal.
The output terminal of the circuit 82 is connected to the base of a transistor 84 that switches on/off the supply of electricity to the buzzer 20.

The electromagnetic valve power supply circuit 19 sends a control signal for energizing the electromagnetic valve 2 only when control signals from the starting gas leakage signal circuit C3 and lock signal circuit C6 are absent and a control signal from the starting signal circuit C2 is received. It consists of an output solenoid valve energization signal circuit C10. This solenoid valve energization signal circuit C10 includes a NAND circuit 8 in which a start signal circuit C2 and a lock signal circuit C6 are connected.
6 is connected to the base of a transistor 89 which opens and closes the energization to the solenoid valve 2 via the NOT circuit 85, and the starting gas leak signal circuit C3 is connected to the input end of the NOT circuit 85. Become.

In Fig. 3, 14 is an abnormality signal processing circuit, and although an abnormality detector connected to this abnormality signal processing circuit 14 is not shown, it includes a flame sensing element that detects combustion by opening and closing an electric circuit, and a gas leak alarm. Connect the transfer signal circuit of a device, an earthquake detector whose electric circuit opens and closes due to vibration, and other equipment that turns ON (turns OFF by reversing) due to an abnormality. The abnormal signal processing circuit 14 includes an abnormal signal circuit C1 that outputs a control signal to the electromagnetic valve power supply circuit 19 when the switch S is turned on. This abnormality signal circuit C1 detects an abnormality when a predetermined input voltage drops by turning on a switch S, and this abnormality signal is inverted by a NOT circuit 61 and is output by a combination of a resistor 62 and a capacitor 63. A timer delays the signal for a predetermined period of time (for example, 3 seconds). This is because, for example, when using this timer to detect extinguishing using a flame sensing element, the flame may be swayed by wind or the like and may temporarily detect non-flammability. In the present invention, the first pressure switch 3a constituting the pressure switch 3 is an interlocking switch 5a which is turned ON when a gas use start signal is issued from the manual switch 5.
The series set of the first pressure switch 3a and the interlocking switch 5a is connected in parallel with the second pressure switch 3b, which also constitutes the pressure switch 3, through the first pressure switch 3a and the interlocking switch 5a. An overflow signal indicating a drop in gas pressure is sent to the control panel 6, and a pipe leak signal indicating a large drop in gas pressure is sent to the control panel 6 by the second pressure switch 3b after the gas is used. This interlocking switch 5a is the switch 5
However, in this embodiment, a separate switch is used, which turns on when the manual switch 5 is turned on, and turns off when it is turned off.

〓Effect of the invention〓 The present invention is as described above, and the pressure switch 3 is
It consists of a first pressure switch 3a that issues a pressure reduction signal when the gas pressure falls below a predetermined value, and a second pressure switch 3b that issues a pressure reduction signal when the gas pressure falls further below this predetermined value. The pressure switch 3a connects the series set of the first pressure switch 3a and the interlocking switch 5a and the second pressure switch 3b in parallel through the interlocking switch 5a which is turned ON when the manual switch 5 issues a gas use start signal. When gas is used, the first pressure switch 3a sends an overflow signal, which is a small drop in gas pressure even though there is a large amount of leakage, and after gas is used, the second pressure switch 3a sends an overflow signal.
Control panel 6 detects a piping leak signal indicating that the amount of leakage is small due to b, but the gas pressure drops significantly over time.
Therefore, if you turn on the manual switch 5 when you do not want to use gas, the interlock switch 5a will also turn on, and as a result, if a rubber hose etc. comes off while gas is being used and a large amount of gas leaks at once. The pressure switch 3a instantly detects this, sends an overflow signal to the control panel 6 (pressure switch signal processing circuit 16), closes the solenoid valve 2, and automatically cuts off the gas supply. Also, after using gas, turn off manual switch 5.
If it is turned OFF, the interlocking switch 5a will also be OFF, so even if the first pressure switch 3a is turned ON, the above-mentioned overflow signal will not be sent to the control panel 6, and the pipe will not leak until the second pressure switch 3b is turned ON. A signal is sent to the control panel 6, and it is possible to provide a gas safety device that can detect small gas leaks without being affected by temperature changes.

[Brief explanation of drawings]

Fig. 1 is a front view showing one embodiment of the gas safety device of the present invention, Fig. 2 is a sectional view of the pressure switch section, and Fig. 3 is a sectional view of the pressure switch section.
The figure shows the logic circuit diagram of the control panel. DESCRIPTION OF SYMBOLS 1... Gas supply path, 2... Solenoid valve, 3... Pressure switch, 3a... First pressure switch, 3b...
Second pressure switch, 5...Manual switch, 5a...
...Interlocking switch, 6...control panel.

Claims (1)

[Scope of Claim for Utility Model Registration] A solenoid valve 2 for opening and closing gas supply to the downstream side of the gas supply passage 1 is disposed at an upstream portion of the gas supply passage 1, and a gas supply passage downstream from the solenoid valve 2 is provided. 1 is equipped with a pressure switch 3 that issues a pressure reduction signal when the gas pressure falls below a predetermined value, and further includes a manual switch 5 that issues a gas usage start signal when gas usage starts, and the manual switch 5 and the pressure switch 3. In the gas safety device, the pressure switch 3 is controlled by a first pressure switch 3 which issues a pressure drop signal when the gas pressure falls below a predetermined value.
a, and a second pressure switch 3b that issues a pressure drop signal when the gas pressure drops further below this predetermined value.
The first pressure switch 3a is connected in series to the series combination of the first pressure switch 3a and the interlocking switch 5a through an interlocking switch 5a which is turned ON when the manual switch 5 issues a gas use start signal. A second pressure switch 3b is connected in parallel, and when gas is used, the first pressure switch 3a sends an overflow signal which is a small gas pressure drop, and after gas use is finished, the second pressure switch 3b sends a large gas pressure drop. A gas safety device characterized in that a pipe leakage signal is transmitted to a control panel 6.