JPH0319428B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas leak cutoff device that cuts off gas supply when gas such as city gas leaks.

Such conventional gas leakage shutoff devices are configured to shut off a gas release valve by means of an output from a means for detecting leakage gas. Therefore, when attempting suicide, etc., cover the leak gas detection area airtight with tape, etc., so that even if gas leaks, the release valve will not be shut off, and leave the gas shut-off valve open. It is possible to become.

An object of the present invention is to provide a gas leak isolation device with improved safety.

The present invention includes a means for detecting the proximity or contact of a human body, and a detection means for detecting the proximity or contact of a human body by the proximity detection means in response to an output from the proximity detection means for a predetermined period of time or more. a delay circuit for deriving a delayed detection signal when the gas is detected; a means for detecting leaked gas; and a delay circuit for deriving a delayed detection signal when the leaked gas is detected; A gas leak cutoff device characterized in that it includes means for cutting off an on-off valve.

The present invention also provides a means for detecting the proximity or contact of a human body, and a means for detecting the proximity or contact of a human body by the proximity detection means in response to an output from the proximity detection means for a predetermined period of time or longer. It has a delay circuit that derives a delay detection signal when the delay circuit continues, a means for detecting leakage gas, and a flip-flop that is set to one stable state in response to the delay detection signal from the delay circuit. After receiving the leaked gas detected output from the leaked gas detection means,
A bistable means that is reset to the other stable state when leakage gas is no longer detected by the leakage gas detection means; a flip-flop in the one stable state; and a bistable means that detects leakage gas from the leakage gas detection means. The gas leakage shut-off device is characterized in that it includes means for shutting off the gas on-off valve when at least one of the outputs occurs and opening the gas on-off valve when the flip-flop is in the other stable state.

FIG. 1 is an overall system diagram of an embodiment of the present invention. A main body 3 is provided on a ceiling 2 of a house 1 or the like. This main body 3 is energized by electrical power via line 4 . The signal from the main body 3 is embedded in the side wall of the house 1 via line 5.
Line 5 is connected to repeater 6 . The output from the repeater 6 is sent via a line 7 to shut off the gas on-off valve 8 in the event of a gas leak. Gas such as city gas passes through a gas meter 10 from a conduit 9 to a gas on-off valve 8, and is supplied from a conduit 11 to a gas consuming device 12 installed in the house 1, such as a gas water heater or a gas range.

FIG. 2 is an overall system diagram of another embodiment of the present invention, in which parts corresponding to those of the previous embodiment are given the same reference numerals. In this example, subject 3 is house 1
The repeater 6 is also attached to the wall.

FIG. 3 is an electrical circuit diagram of the main body 3. The power from line 4 is stepped down by a transformer 13 to energize a leaked gas detection element 14 made of a semiconductor, for example, and a DC voltage is supplied to line 16 via a rectifier circuit 15. Ru. The output from transformer 13 is also given to another rectifier circuit 17 whose output is connected to line 1
It is derived between 8 and 19. The output from the gas detection element 14 is derived from a line 20 and is connected to a resistor 21,
22. The voltage-divided waveform at the connection point 23 is as shown in FIG. The output from line 23 is diode 2
4 and a capacitor 25, and is then rectified by a comparator circuit 26 via an adjustment circuit 27
is applied to one input of 8. The output from the rectifier circuit 26 is as shown in FIG. 42.
Another input of the comparator circuit 28 includes a resistor 29,
30, the voltage between lines 18 and 19 is divided and applied, and a discrimination level l1 is determined. The comparison circuit 28 derives a low level signal when the output level from the regulator 27 is equal to or higher than the discrimination level l1. The low level output from the comparator circuit 28 is led out to a line 31 and connected to a light emitting diode 32.
At the same time, the light emitting diode 34 included in the photocoupler 33 is caused to emit light.
The output from line 31 also resets flip-flop 35 via line 53 from differential capacitor 94.

The set output Q of flip-flop 35 is applied from line 36 to one input of another comparator circuit 37. The other input of the comparison circuit 37 is
The voltage between the lines 16 is divided by voltage dividing resistors 38 and 39 and applied to set a discrimination level l2 (see FIG. 5 and FIG. 7, which will be described later). When the output from the line 36 is above the discrimination level l2, the comparator circuit 37 sets the line 40 to a low level, causing the light emitting diode 41 to emit light and at the same time, the light emitting diode 43 of the photocoupler 42 lights up. The bistable means described in the claims section is the flip-flop 35 in this embodiment.
and capacitors 68, 94, etc.

A phototransistor 44 included in the photocoupler 33 receives and outputs the output of the light emitting diode 34, which causes a transistor 45 to shut off. At the base of the transistor 46 interposed in series between line 16 and line 5 are two Zener diodes 47 connected in opposite directions,
48 are connected in series. transistor 45
are connected in parallel to the Zener diode 48.

A phototransistor 49 included in the photocoupler 42 receives the light from the light emitting diode 43 and becomes conductive, thereby causing the transistor 50 to shut off. By blocking transistor 50, transistor 51 becomes conductive, so that the voltage on line 5 becomes zero. Diode 52 in series with line 5
is connected.

The main body 3 has a plate-shaped detection piece 53 made of a conductive material such as metal. This detection piece 53 is connected to an amplifier circuit 54. When a human body 55 approaches or contacts the detection piece 53, the amplifier circuit 5
4 introduces an induced hum in line 56 with large amplitude. The output from this line 56 is applied via a coupling capacitor 57 to a rectifier circuit 60 consisting of a diode 58 and a capacitor 59 for rectification, and is applied via a regulator 61 to one input of a comparator circuit 62. The voltage on the line 16 is divided by resistors 63 and 64 and applied to the other input of the comparator circuit 62, and the reference level l3 (the fifth
(see Figure 2). Comparison circuit 62 derives a high level signal to line 65 when the output from regulator 61 is equal to or higher than discrimination level l3. Delay circuit 6
6 derives a high level signal when the high level signal from the line 65 continues for a predetermined time W or more, and then becomes low level at the same time as the line 65 becomes low level. This delay circuit 66 also operates on line 67 when the period during which the signal on line 65 is at a high level is less than W.
remains at a low level. The output from delay circuit 66 on line 67 sets flip-flop 35 via differential capacitor 68. Flip-flop 35 changes its stable state in response to a rising signal.

Referring to FIG. 4, when gas is not leaking before time t1, the signal level derived to line 20 of gas detection element 14 is small as shown in FIG. 41. At this time, the output from the rectifier circuit 26 is below the discrimination level l1 of the comparator circuit 28 as shown in FIG. 42, and therefore the output on line 31 of the comparator circuit 28 is as shown in FIG. is at a high level. Therefore, the light emitting diodes 32 and 34 are turned off. The waveform of the signal derived from differential capacitor 94 on line 53 is a falling waveform as shown in FIG. 4, and flip-flop 35 remains set. Therefore line 40 from comparator circuit 37
The output at is at a high level, and the light emitting diodes 41 and 43 are off. Therefore, the phototransistor 49 is cut off. transistor 5
0 is conductive, and transistor 51 is cut off.
Further, as described above, since the light emitting diode 34 is off, the transistor 44 is cut off, and therefore the transistor 45 is conductive, so that the voltage V1 determined by the Zener diode 47 is applied to the line 5. is derived. This voltage V1
For example, is 6V.

When gas leaks between times t1 and t2, the amplitude of the signal derived from the gas detection element 14 to the line 20 increases, and the output from the rectifier circuit 26 becomes
If the discrimination level is l1 or higher. Therefore, the comparison circuit 28
The output on line 31 becomes low level,
The light emitting diode 32 lights up to display light emission, and the light emitting diode 34 lights up. By lighting the light emitting diode 34, the phototransistor 4
4 conducts and transistor 45 cuts off, which causes two Zener diodes 4 in line 5.
7, 48 is derived. Voltage V2 is, for example, 12V. When a gas leak occurs in this way, a voltage V2 is generated in the line 5 only during that period, and this causes a voltage V2 to be generated from time t1 to t.
2, the gas on-off valve 8 is shut off as described later.

Let us assume that the gas detection element 14 and therefore the main body 3 are hermetically sealed with tape or the like in order to cause the gas sensor 14 to lose its detection function and commit suicide. A human body 55 is in close proximity to or in contact with the gas detection element 14 and the main body 3 in order to apply the tape, and the time for applying the tape exceeds the time W determined by the delay circuit 66. In such a case, the amplifier circuit 5 from the detection piece 53
The signal input to line 54 is shown in FIG. 51, and the signal led out from amplifier circuit 54 to line 56 has a waveform that is an amplified version of the signal shown in FIG.

Before time t3, the human body 55 is not close to or in contact with the detection piece 53, and therefore the waveform of the signal derived from the rectifier circuit 60 is as shown in FIG.
As shown, it remains at a low level before time t3. The level of the signal applied from the rectifier circuit 60 to the comparison circuit 62 via the adjustment circuit 61 is less than the discrimination level l3. Therefore, the output from the comparator circuit 62 led out to the line 65 remains at a low level as shown in FIG. 5. The signal derived from delay circuit 66 on line 67 is at a low level as shown in FIG.

Flip-flop 3 from differential capacitor 68
The waveform of the signal applied to 5 is shown in FIG. The set output on line 36 of flip-flop 35 is shown in FIG.
Since flip-flop 35 has been reset before time t8, which will be described later, the output of comparator circuit 37 on line 40 is at a high level as shown in FIG. 5. Therefore, the light emitting diodes 41 and 43 are off, and the phototransistor 49 of the photocoupler 42 is cut off.
Therefore, transistor 50 is conductive, and as a result, transistor 51 is turned off. At this time, the gas detection element 14 does not detect any leaked gas, and therefore the transistor 45 is conductive as described above, and as shown in FIG.
Previously, the voltage remains at V1.

From time t3 to time t4, the human body 5 is applied to the detection piece 53 for a period longer than the time W set by the delay circuit 66.
5 approaches or contacts, the amplitude of the human output of the amplifier circuit 54 increases, and the output of the rectifier circuit 60 changes the discrimination level l3 of the comparator circuit 62 from time t3 to t.
It exceeds 4. Therefore, the output on line 65 from comparator circuit 62 remains at a high level, as shown in FIG. The delay circuit 66 at time t3
At time t8, when time W has elapsed since then, a high level signal is derived on line 67 as shown in FIG. Differential capacitor 68 is set by applying a rising pulse to flip-flop 35 at time t8, as shown in FIG. As a result, the output of the flip-flop 35 becomes high level, exceeding the discrimination level l2 of the comparison circuit 37.
Therefore, the output on the line 40 of the comparison circuit 37 becomes a low level as shown in FIG. 5, and the light emitting diodes 41 and 43 light up. As a result, phototransistor 49 becomes conductive, and transistor 5
0 is cut off and transistor 51 is turned on. Thus, line 5 becomes low level as shown in FIG. 5.

Once the human body 55 approaches or contacts the detection piece 53 for a time W or more, the voltage on the line 5 remains zero even if the human body 55 is separated from the detection piece 53. When the voltage on the line 5 is zero, the gas on-off valve 8 remains shut off, as will be described later.

In order to open the gas on-off valve 8 to its original state, a small cylinder or the like filled with the gas to be detected must be manually brought close to or in contact with the gas detection element 14 to detect the gas. It is necessary for the element 14 to detect the gas inside the cylinder.
When the cylinder is held in the hand of the human body 55 and brought close to the detection piece 53, the input and output waveforms of the amplifier circuit 54 are as shown in FIG.
As shown, the amplitude becomes large near times t5 to t7. Therefore, the output from the rectifier circuit 60 changes the discrimination level l3 of the comparator circuit 62 to the time t5.
Exceeds at ~t7. After time t7, time t9
The alarm ends at .

During the period from time t5 to t7, time t6
The gas is blown out from the cylinder. The signal thus led out from the gas detection element 14 to the line 20 has a large amplitude, as shown in FIG. 5. Therefore, the output from the rectifier circuit 26 exceeds the discrimination level l1 of the comparator circuit 28, as shown in FIG. It becomes a low level. As a result, the light emitting diodes 32 and 34 light up, and the phototransistor 44 becomes conductive. Therefore, the transistor 45 is cut off and the voltage on the line 5 becomes V2 as shown in FIG.

At t9 after time t7, when the gas discharge from the cylinder to the gas detection element 14 is stopped, the output of the comparator circuit 28 becomes high level again as shown in FIG. , line 53 has a differential capacitor 9
4 generates a positive differential pulse (ie, the pulse at time t2 as shown in FIG. 4), and flip-flop 35 is reset. Therefore, the reset output on line 36 of flip-flop 35 becomes low level, and the reset output on line 4 of comparator circuit 37 becomes low level.
The output at 0 is high level. Therefore, the light emitting diodes 41 and 43 are turned off and the phototransistor 49 is cut off. This causes transistor 50 to conduct and transistor 51 to shut off.
Therefore, since the transistor 45 is cut off, the voltage on the line 5 becomes a voltage V1 depending on the light emitting diode 47, and the gas on-off valve 8 becomes open as described later.

FIG. 6 is a block diagram showing a specific configuration of the repeater 6. The signal from the main body 3 via the line 5 is transmitted to the comparator circuits 63, 64 from the resistors 61, 62.
are given to one input of each. Comparison circuit 6
Voltages V4 and V5 are applied to the other inputs of 3 and 64, respectively, and the discrimination level l shown in FIG.
4 and l5, respectively. The comparison circuit 63 is
Voltage V2 where the voltage of line 5 is higher than discrimination level l4
When this is the case, that is, when the gas from the gas cylinder or the gas actually leaking is in contact with the gas detection element 14 after the valve is once closed, a high level signal is output to the line 65. Another comparator circuit 64 derives a high level signal on line 66 when the voltage on line 5 is zero volts, less than voltage V1. When line 65 is at high level,
At the same time as the buzzer 67 sounds, the display circuit 68 turns on the lamp 69 to indicate that a gas leak has occurred. The high level signal from line 66 is transmitted to indicator lamp 71 by indicator circuit 70.
is turned on, thereby causing the above-mentioned time t8 to
This indicates that the gas on-off valve 8 is closed at t6. High level signals from the lines 65 and 66 are applied to the drive circuit 73 via the OR gate 72 and amplified, and the voltage on the line 7 is brought to zero and the gas on-off valve 8 is closed.

A specific configuration of the gas on-off valve 8 is shown in FIG. Gas from the gas meter 10 can flow into the pipe line 11 through a valve hole 81 formed in the valve seat 80. The valve body 82 is arranged on the gas downstream side of the valve seat 80 and is connected to the plunger 83. An electromagnetic coil 84 is provided surrounding the plunger 83. This electromagnetic coil 84 is energized by power from line 7. The plunger 83 is biased by a spring 85 so that the valve body 82 is seated on the valve seat 80 and the valve is closed.

When the output of the OR gate 72 in the repeater 6 is at a high level, the drive circuit 73 does not supply power to the line 7, thereby causing the valve body 82 to
It is seated on the valve seat 80 by the spring force of 5, and is in the valve closed state. When the output of OR gate 72 is at a low level, power is supplied from line 7 to electromagnetic coil 84 . As a result, the valve body 82
is separated from the valve seat 80 against the spring force of the spring 85, and the valve is closed and gas is supplied.

As described above, according to the present invention, the gas on-off valve is shut off only when the human body has been in close proximity or has been in contact with the human body for a predetermined time or more using the delay circuit. This prevents the gas on-off valve from being shut off due to contact. After the gas on-off valve is closed due to proximity or contact with a human body, the leakage gas detection means is placed in a state where leakage gas can be detected.In other words, if a tape or the like is attached, remove the tape or the like to detect leakage gas. Since the gas on-off valve will not open unless gases of the same composition are detected by the leaked gas detection means, safety is further improved.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of one embodiment of the present invention, FIG. 2 is a system diagram of another embodiment of the present invention, FIG. 3 is an electric circuit diagram showing the specific configuration of the main body 3, and FIGS. 5 is a waveform diagram for explaining the operation of the main body 3, FIG. 6 is a block diagram showing a specific configuration of the repeater 6, and FIG. 7 is a sectional view of the gas on-off valve 8. 3... Main body, 6... Relay, 8... Gas on/off valve, 14... Gas detection element, 26, 60... Rectifier circuit, 28, 37, 62, 63, 64... Comparison circuit, 35... Flip-flop, 53... detection piece.

Claims (1)

[Scope of Claims] 1. A means for detecting the proximity or contact of a human body; and a means for detecting the proximity or contact of a human body by the proximity detection means in response to an output from the proximity detection means. a delay circuit that derives a delayed detection signal when the signal continues for a period of time or more; a means for detecting leaked gas; and generation of at least one of the delayed detection signal from the delay circuit and the leaked gas detected output from the leaked gas detection means. A gas leak cutoff device characterized in that it sometimes includes means for cutting off a gas on-off valve. 2. A means for detecting the proximity or contact of a human body, and a delay when detection of the proximity or contact of a human body by the proximity detection means in response to the output from the proximity detection means continues for a predetermined period of time or more. It has a delay circuit for deriving a detection signal, a means for detecting leakage gas, and a flip-flop that is set to one stable state in response to the delay detection signal from the delay circuit, and the flip-flop is configured to detect leakage gas. After receiving the output that detected leaking gas from
A bistable means that is reset to the other stable state when leakage gas is no longer detected by the leakage gas detection means; a flip-flop in the one stable state; and a bistable means that detects leakage gas from the leakage gas detection means. 1. A gas leakage shutoff device comprising: means for shutting off a gas on-off valve when at least one of the outputs occurs, and opening the gas on-off valve when the flip-flop is in the other stable state.