JPH0751714Y2 - Gas switch with pressure drop indicator - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a gas switch with a pressure drop display device capable of early detection of a pressure drop due to gas leakage to prevent damage to equipment.

[Conventional technology]

FIG. 3 shows an example of a control circuit of a conventional gas switch. In the figure, the trip mechanism VTC,
Built-in overcurrent detector OCR, switch main contactor interlock switch S, and zero-phase current transformer ZCT. The output of the zero-phase current transformer ZCT is determined by the zero-phase current detection circuit 1 to be a set value or more, and when it is the set value or more, an output pulse is output to the CPU 2.

On the other hand, the non-voltage detector 3 is connected between the AC power supply terminals P ₁ and P _2.
And a diode D ₁ and a capacitor C that convert AC to DC
A rectifying / smoothing circuit is provided. The DC voltage obtained by this is connected to the V _a terminal via the contact TRIP of the trip relay 4, and the voltage divided by the resistors R ₁ and R ₂ is passed through the light emitting side LED of the photocoupler 6 and the diode D ₂ . Connected to the V _b terminal. The ground line 11 of the DC voltage is connected to V _c terminal is connected to the common terminal of the overcurrent detection device OCR in switch. The above terminals
The control lines that connect V _a , V _b , and V _c to the switch are trip signal line 9, overcurrent detection line 10, and earth line 11, respectively.

The light receiving side phototransistor of the photocoupler 6 is connected to the input port of the CPU 2.

The output judged by the zero-phase current detection circuit 1 to be above the set value is CP.
When it is input to U2, the timer is clocked (0.1 to 0.3 seconds), and when the clock is finished, it is output to trip relay 4 and target 5.

When an overcurrent flows and the overcurrent detection device OCR operates, the fact that an overcurrent has flown is input to the CPU 2 by the photocoupler 6.
After that, if P ₁ and P ₂ become non-voltage within a fixed time, for example, 1.8 seconds, 1.5 seconds after the voltage becomes non-voltage, only the trip relay 4 is operated.

[Problems to be solved by the device]

However, in such a conventional gas switch, since a signal line for transmitting a signal of pressure drop must be newly added, a dedicated controller is required, and the existing controller cannot be used. Furthermore, there is a problem that the control line for connection between the gas switch and the control device must be replaced.

Therefore, the present invention uses a control line for connecting the gas switch and the control device to transmit a pressure drop signal, and by connecting a pressure drop display device to the terminal of the existing control device, the pressure drop can be reduced at an early stage. The purpose is to discover.

[Means for Solving the Problems]

To achieve this object, the gas switch with pressure drop display device of the present invention has at least an overcurrent detection device OCR and a gas switch equipped with a switch trip mechanism VTC, and at least the overcurrent detection device OCR is activated. The control device is provided with an overcurrent detection transmission circuit 6 for detecting the occurrence of a failure and a relay 4 for operating the trip mechanism VTC by the action of the overcurrent detection transmission circuit 6 at the time of overcurrent. In a gas switch for transmitting a signal to and from a switch through a control line composed of a trip signal line 9, an overcurrent detection line 10 and an earth line 11, a common terminal is provided on the gas switch side and the trip signal line 9 is provided.
In addition, a pressure drop detection device PRS is provided so that normally open contacts are connected to the overcurrent detection line 10, respectively, the common terminal of the overcurrent detection device OCR is the earth line 11, and the normally closed contact is the trip mechanism. To the VTC, normally open contacts are connected to the overcurrent detection line 10, respectively, and on the control device side, a reverse current element 7 is connected in parallel to the trip contact TRIP and the rectifier D ₁ connected to the trip signal line 9. The overcurrent detection line 10
The reverse flow element D ₄ and the gas pressure drop display device 8 are connected in series between the ground line 11 and the earth line 11.

In this gas switch, the normally closed contact side of the working contact of the pressure drop detection device PRS is connected to the trip signal line 9 and the trip mechanism VT.
By connecting it to C, it is possible to prevent the accident that the trip contact is activated and the circuit cannot be shut off when the gas pressure decreases.

[Action]

In the present invention, if the gas pressure in the switch decreases,
It is transmitted to the control device through the overcurrent detection line 10 which transmits a signal from the overcurrent detection device. On the control device side, a trip contact connected to the trip signal line 9, a rectifier D ₃ and a resistor R ₃ connected in parallel to the rectifier, and an overcurrent detection line 10
Since the rectifier D ₄ and the pressure drop display device 8 are connected in series between and the earth line 11, the display of the pressure drop is performed on the control device side.

In this gas switch, the normally closed contact side of the working contact of the pressure drop detection device PRS is connected to the trip signal line 9 and the trip mechanism VT.
By connecting it to C, the trip mechanism is not supplied with a voltage for tripping the switch when the pressure drops, and the load current is not cut off. Therefore, the switch is prevented from being damaged due to a decrease in gas pressure.

〔Example〕

 Hereinafter, the present invention will be described in detail based on embodiments.

FIG. 1 shows an embodiment of a gas switch with a pressure drop display device according to the present invention. In the figure, the components having the same or similar functions as those of the conventional configuration shown in FIG.

In FIG. 1, if the pressure of the gas switch is lowered, the pressure drop detection device PRS is activated, and the power source is P ₂ → pressure drop display device 8 → backflow element (for example, rectifier) D ₄ → overcurrent detection line 10
→ Pressure drop detection device PRS → Trip signal line 9 → Backflow element 7 (rectifier D ₃ → Resistor R ₃ ) → Power is supplied to the pressure drop display device 8 through P ₁ to display the pressure drop and give an alarm. Can be made.

FIG. 2 shows another embodiment of the gas switch according to the present invention.
In the second embodiment, the normally closed contact side of the working contact of the pressure drop detecting device PRS is connected between the trip signal line 9 and the trip mechanism VTC so that the trip circuit is opened when the pressure drops. So that the switch is not shut off. That is, in the case of the embodiment shown in FIG. 2, when the gas pressure is suddenly reduced and replaced with air, the trip contact is activated to cause interruption, and the switch is punctured. The vessel did not shut off. In the case of the embodiment of FIG. 1, no such protection is provided.

[Effect of device]

As described above, according to the present invention, the pressure drop signal can be transmitted by using the control line for connecting the gas switch and the control device, which is conventionally wired instead of the dedicated signal line. Because it can be done, the economic effect is great. Further, since the pressure drop display device can be added to the terminal of the control device, there is an advantage that a dedicated control device is not necessary and the conventional control device can be used as it is.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a gas switch with pressure drop display device according to the present invention, FIG. 2 is a circuit diagram showing a second embodiment of the present invention, and FIG. 3 is a conventional embodiment. It is a circuit diagram. 1: Detection circuit, 2: CPU 3: No-voltage detection device, 4: Trip relay 5: Target 6: Overcurrent detection transmission circuit, 7: Reverse current element 8: Pressure drop display device, 9: Trip signal line 10: Overcurrent Detection line, 11: Earth line

Claims (2)

[Scope of utility model registration request] 1. A gas switch having at least an overcurrent detector (OCR) and a switch trip mechanism (VTC),
At least an overcurrent detection transmission circuit (6) for detecting the operation of the overcurrent detection device (OCR) and a relay for operating the trip mechanism (VTC) by the action of the overcurrent detection transmission circuit (6) at the time of overcurrent (4) is provided with a control device, and the signal transmission between the control device and the gas switch is made up of a trip signal line (9), an overcurrent detection line (10), and an earth line (11). In a gas switch operated by a control line, on the gas switch side, a common terminal is connected to the trip signal line (9), and a normally-open contact is connected to the overcurrent detection line (10). A device (PRS) is installed,
The common terminal of the overcurrent detection device (OCR) is connected to the earth line (11), and the normally closed contact is connected to the trip mechanism (VTC).
In addition, the normally open contacts are respectively connected to the overcurrent detection line (10), and on the control device side, the trip contacts (TRIP) and the rectifier (D ₁ ) connected to the trip signal line (9) are connected in parallel. Connect the backflow element (7) to the above-mentioned overcurrent detection line (10)
A gas switch with a pressure drop display device, characterized in that a backflow element (D ₄ ) and a gas pressure drop display device (8) are connected in series between and the earth line (11). 2. A trip signal line (9) and a trip mechanism (VT) are provided on the normally closed contact side of the working contact of the pressure drop detection device (PRS).
The gas switch with a pressure drop display device according to claim 1, wherein the gas switch is connected to C).