JPH05240216A - Fluid opening and closing device - Google Patents

Abstract

PURPOSE:To provide a convenient gas meter equipped with a safety shutdown function by shortening returning safety confirmation period. CONSTITUTION:This fluid opening and closing device is provided with a solenoid valve 5 which opens and closes a tube through which fluid passes, the first timer means 8 which outputs a signal for closing the solenoid valve 5 at a fixed period after the solenoid valve 5 has been switched from a closing condition to an opening condition by an indication from the outside, the second timer means 9 which inputs a signal of closing the solenoid valve 5 from the first timer means 8, starts time measuring operation and outputs it after a fixed period, a pressure measuring means 6 which measures fluid pressure at the downstream side of the solenoid valve 5, and a pressure drop detecting means 7 which detects if the pressure measured by the pressure measuring means 6 has dropped. The pressure drop detecting means 7 is designed to output a signal of opening the solenoid valve 5 if pressure drop does not occur during a fixed period from the time when the second timer means 9 starts its operation to the time when the second timer means 9 completes its operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called microcomputer meter called a gas meter with a safety function.

[0002]

2. Description of the Related Art In recent years, in order to prevent an explosion accident due to a gas leak and a fire accident due to forgetting to turn off a gas appliance, the gas meter monitors the gas leak and the usage time of the gas appliance, and the gas appliance is used for a long time. If it is kept open, it is judged that the gas appliance has been forgotten to be turned off, and a fluid switchgear for cutting off the gas supply has been installed.

Such a conventional fluid switchgear will be described with reference to FIGS. 3 and 4. FIG. 3 is a gas piping diagram showing a gas meter installed in a home and connected to a gas appliance. In FIG. 3, 101 is a house, 102 is a gas meter, 103 is a primary gas pipe, 104 is a secondary gas pipe, 105 is a gas stove, 106 is a gas table, 107 is a bathtub, and 108 is a water heater. And
These appliances are connected to the secondary gas pipe 104.
The gas meter 102 displays an integrated value of gas flow rates used in the gas appliances 105 to 108 connected to the secondary pipe 104, and monitors the gas usage status of each of the gas appliances 105 to 108 to use dangerous gas. When the situation is discovered, the gas shutoff valve built in the gas meter 102 is operated to shut off the gas.

FIG. 4 is a block diagram of a conventional fluid switchgear incorporated in the gas meter 102. 10 in the figure
Reference numeral 3 is a primary gas pipe, and 104 is a secondary gas pipe. And the means which comprises a fluid switchgear is as follows. Reference numeral 1 is a flow rate measuring means, 2 is a pulse detecting means, 3 is a timer means, 4 is a valve driving means, and 5 is an electromagnetic valve. The terminal a is a valve opening signal from the outside.

The operation of the fluid switchgear having the above structure will be described with reference to FIGS. 3 and 4. Gas meter 1
02, gas flow is monitored and gas appliances 105-10
When 8 is used abnormally, the gas meter 102 is configured to drive the solenoid valve 5 shown in FIG. 4 to cut off the gas supply to the secondary gas pipe 104 (see FIG. (Not shown). When the solenoid valve 5 is driven and the gas is shut off, a person checks the gas appliances 105 to 108 and closes the cocks of all the gas appliances. Then, the gas meter 10
Go to 2 and press the knob of the solenoid valve 5 to mechanically
To open. The subsequent operation will be described with reference to FIG. When the solenoid valve 5 is opened, a valve open signal is input to the terminal a. Then, the pulse detecting means 2 and the timer means 3 start operating. The pulse detecting means 2 detects the pulse signal from the flow rate measuring means 1. The flow rate measuring means 1 is configured to generate an electric signal of one pulse every time 0.7 liter of gas passes through the gas meter 102. The timer means 3 outputs a signal for ending the operation of the pulse detection means 2 when 2 minutes have passed. Therefore, when a pulse signal is generated within 2 minutes after the solenoid valve 5 is opened, a signal is generated from the pulse detection means 2 to drive the solenoid valve 5 via the valve drive means 4 to cut off the gas supply again. That is, when there is a gas flow of 21 liters / h, it is determined that there is a gas leak, and the gas is shut off again to ensure safety. Two minutes for this safety confirmation are called return safety confirmation time.

[0006]

However, in the conventional structure as described above, a recovery safety time of 2 minutes is required to detect a gas leak of 21 liter / h or more, and
There was a problem that the gas appliance could not be used for a minute, which was very inconvenient and dangerous for the user.

The present invention solves the above problems and provides a fluid switchgear capable of shortening the return safety time.

[0008]

In order to achieve the above object, a fluid opening / closing device of the present invention comprises a solenoid valve for opening and closing a passage through which a fluid flows, and a solenoid valve which is operated from closed to open.
A first timer means for outputting a signal for closing the solenoid valve after a certain period of time and a signal for closing the solenoid valve from the first timer means are input to start a time measuring operation and output after a certain period of time. Generating a second timer means, a pressure measuring means for measuring the pressure of the fluid downstream of the solenoid valve, and a signal from the first timer means to start the operation and a signal from the second timer means to start the operation. And a pressure drop detecting means for detecting whether or not the pressure measured by the pressure measuring means has ended, the pressure drop detecting means starts operation of the second timer means, and the second timer When a pressure drop does not occur within a fixed time when the means completes its operation, a signal for opening the solenoid valve is output.

[0009]

With the above structure, the present invention can detect the pressure drop in a short time even if there is a slight gas leak, so that the recovery safety confirmation time can be shortened.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The same parts as those in the conventional example are designated by the same reference numerals. In FIG. 1, 103 is a primary gas pipe, 104
Is a secondary side gas pipe, 4 is a second valve driving means, 5 is a solenoid valve connected to the primary side gas pipe 103, 6 is a pressure measuring means connected to the secondary side gas pipe 104, and 7 is a pressure drop detecting means. , 8 is first timer means, 9 is second timer means, 10 and 11 are OR circuits, 12 is first valve driving means,
Reference numeral 13 is a display means. A valve opening signal is input to the terminal a and a valve closing signal is input to the terminal b.

The solenoid valve 5 has a structure that can be opened and closed electrically. When the valve open signal is input to the terminal a from the closed state of the solenoid valve 5, the solenoid valve 5 is opened via the first valve drive means 12. Then, the primary gas pipe 103
Gas is supplied to the secondary side gas pipe 104 from the secondary side gas pipe 104, and the gas pressure in the secondary side gas pipe 104 is a specified pressure (about 280 mmH ₂ O).
Becomes Further, the valve opening signal input to the terminal a causes the first timer means 8 to start operating, and the time required for the gas pressure in the secondary gas pipe 104 to reach a specified pressure (for example, 5).
After a lapse of seconds, an output signal is generated from the first timer means 8. The pressure drop detecting means 7 and the second timer means 9 are activated by a signal from the first timer means 8, and at the same time, the solenoid valve 5 is driven through the OR circuit 11 and the second valve driving means 4 to be in the closed state. To do. The internal volume of the secondary gas pipe 104 is, for example, a pipe length of 10 m and a pipe cross-sectional area of 1 cm.
^{If it is 2} , the internal volume will be 1 liter. If there is a gas leak of 21 liter / h in the secondary gas pipe 104, it is calculated that about 0.058 liter of gas leaks in one second. This is about 0.58 of the internal volume of the secondary gas pipe 104.
Equivalent to%. That is, if there is a gas leak of 21 liter / h or more in the secondary gas pipe 104 with the solenoid valve 5 closed, 0.58% or more of the gas trapped in the secondary gas pipe 104 in 1 second Gas will be lost.
This is a pressure decrease of about 58 mmH ₂ O or more when converted to pressure. Therefore, the gas leak can be detected by detecting the decrease in the gas pressure in the secondary gas pipe 104 by the pressure measuring means 6 and the pressure decrease detecting means 7. When a gas leak is detected, a gas leak signal is output to the display means 13 and the display means 13 displays the gas leak.

Next, consider the case where there is no gas leakage.
With the second timer means 9, even if the length of the secondary side gas 104 is long, if there is a gas leak, the pressure drop will be 50 mm.
A time sufficient to generate H ₂ O or more, for example, 10 seconds is measured. Then, after the second timer means 9 starts operating, 1
After 0 second, a signal is sent to the pressure drop detecting means 7. In the pressure drop detecting means 7, the pressure drop detecting operation is stopped by the signal from the second timer means 9, and when the pressure drop is not detected, the solenoid valve is operated via the OR circuit 10 and the first valve driving means 12. Open 5 As described above, when there is no gas leakage, the gas appliances 105 to 108 are ready for use 15 seconds after the valve opening signal is input to the terminal a.

FIG. 2 shows a flow chart for explaining the operation of the pressure drop detecting means 7. In step 71, it is detected whether or not there is an activation signal input from the first timer means 8,
If there is a start signal, the gas pressure in the secondary side gas pipe 104 is measured through the pressure measuring means 6 in step 72 and set to P1. In step 73, the pressure measurement value P1 is used as a reference value.
In step 74, the gas pressure in the secondary gas pipe 104 is measured again and set to P2. If the difference between the reference value P1 and the measured value P2 exceeds 50 mmH ₂ O in step 75, it is determined that there is a gas leak, and in step 76 a display output is sent to the display means 13. Then, in step 77, the operation ends. On the other hand, if the difference between the reference value P1 and the measured value P2 is 50 mmH ₂ O or less in step 75, it is detected in step 78 whether there is an operation end signal from the second timer means 9, and if there is an operation end signal, step At 79, a valve opening signal is output to the first valve driving means 12 via the OR circuit 10. And step 80
To end the operation. If there is no operation end signal in step 78, the process returns to step 71.

[0014]

As described above, according to the fluid switchgear of the present invention, when the solenoid valve is closed due to an abnormal condition or the like, all the gas plugs are closed and then the solenoid valve is opened. After performing the operation, the return safety confirmation can be performed in a short time of, for example, 15 seconds, which improves usability.

[Brief description of drawings]

FIG. 1 is a block diagram of a fluid switchgear according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the pressure drop detecting means of the present invention.

[Figure 3] Gas piping diagram at home

FIG. 4 is a block diagram of a conventional fluid switchgear.

[Explanation of symbols]

 1 flow rate measuring means 2 pulse detecting means 3 timer means 4 second valve driving means 5 solenoid valve 6 pressure measuring means 7 pressure drop detecting means 8 first timer means 9 second timer means 10, 11 OR circuit 12 first Valve driving means 103 Primary gas pipe 104 Secondary gas pipe

Claims (1)

[Claims] 1. A solenoid valve for opening and closing a passage through which a fluid flows, and a first timer means for outputting a signal for closing the solenoid valve after a predetermined time when the solenoid valve is operated from closed to open.
A second timer means for inputting a signal for closing the solenoid valve from the first timer means to start a time measuring operation and producing an output after a fixed time, and a pressure measurement for measuring the fluid pressure downstream of the solenoid valve. Means, and a pressure drop detecting means for detecting whether or not the pressure measured by the pressure measuring means has dropped, the pressure drop detecting means, the second timer means starts the operation, the second A fluid opening / closing device configured to output a signal for opening the solenoid valve when a pressure drop does not occur within a fixed time period when the timer means completes its operation.