JP3136799B2 - Safety valve drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety valve driving device for gas-fired equipment.

[0002]

2. Description of the Related Art In recent years, safety valves,
Attention has been focused on a solenoid valve, a thermocouple, a microcomputer (hereinafter, referred to as a microcomputer), and a safety valve driving device using an abnormality monitoring device.

[0003] A conventional safety valve driving device will be described below. FIG. 4 shows a thermocouple 11, a safety valve 12 connected in parallel to the thermocouple 11 to open and close a gas supply path, and a safety valve 12.
Switching means for connecting or disconnecting the thermocouple 11 from the relay 1, for example, a solenoid valve switch 13 (hereinafter referred to as a relay), and a relay 1
This is a conventional example of a safe drive device including a microcomputer 14 that supplies a relay drive current I11 to an electromagnetic coil 3 and an abnormality monitoring device 15 that notifies the microcomputer 14 of abnormality detection. During the combustion, the relay drive current I11 from the microcomputer 14 flows, and the contact of the relay 13 is closed. Therefore, safety valve 1
2 is a current I12 generated by the thermoelectromotive force from the thermocouple 11.
Flows through the electromagnetic coil to maintain the valve open state. When the abnormality monitoring device 15 detects an abnormality, the abnormality monitoring device 15 notifies the microcomputer 14 of the abnormality detection, and the microcomputer 14 that has received the abnormality detection stops the relay driving current I11 flowing through the relay and opens the contact of the relay 13. , Relay 1
When the contact 3 opens, the current I12 generated by the thermoelectromotive force from the thermocouple 11 is not transmitted to the safety valve 12, so that the safety valve 12 is closed, the gas supply path is closed, and the fire is extinguished.

FIG. 5 shows a thermocouple 21 and a thermocouple 21.
A safety valve including a microcomputer 22 for detecting a thermoelectromotive force E21 from the microcomputer, an electromagnetic valve 23 for opening and closing the gas supply path by an electromagnetic valve driving current I21 from the microcomputer 22, and an abnormality monitoring device 24 for notifying the microcomputer 22 of abnormality detection. It is a conventional example of a drive device. During combustion, the solenoid valve drive current I21 flows from the microcomputer 22 to the solenoid coil of the solenoid valve 23, and the solenoid valve 23
Keeps the valve open. Thermocouple 21 when going out
Loses the thermoelectromotive force E21, so that the thermocouple 21
When the microcomputer 22 detects that the solenoid valve 21 has been lost, the microcomputer 22 sends the solenoid valve driving current I21
Stop. Therefore, the solenoid valve 23 is closed, the gas supply path is closed, and the fire is extinguished. When the abnormality monitoring device 24 detects an abnormality such as a control circuit abnormality during combustion, the abnormality monitoring device 24
Informs the microcomputer 22 of the abnormality detection, and upon receiving the abnormality detection, the microcomputer 22 stops the electromagnetic valve drive current I21 flowing through the electromagnetic valve 23. Therefore, the solenoid valve 23 is closed, the gas supply path is closed, and the fire is extinguished.

[0005]

However, in a configuration in which a relay is connected between a thermocouple and a safety valve as in the conventional example of FIG. 4, since the resistance of the safety valve is as small as several tens of milliohms, the thermoelectric resistance due to the contact resistance of the relay is small. The reduction of the current caused by the thermoelectromotive force of the pair due to the contact resistance of the relay cannot be ignored, and it becomes difficult to maintain the safety valve open by the current generated by the thermoelectromotive force of the thermocouple. Therefore, there is a problem that it is necessary to select a relay having a small contact resistance and the cost increases.

In the conventional example shown in FIG. 5, there is a problem that a driving device for driving the solenoid valve is required and that the configuration becomes complicated because it is necessary to consider an instantaneous power failure or an instantaneous voltage drop. Was.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a low-cost safety valve driving device which is highly reliable, has a simple structure, and is low in cost.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a safety valve driving device according to the present invention uses a current generated by a thermoelectromotive force from a thermocouple when the safety valve maintains an open state. The safety valve is configured to be closed by applying a triangular wave voltage having a potential that generates a canceling current to the safety valve.

[0009]

According to the device of the present invention, when a triangular wave voltage is applied to the safety valve while the safety valve is maintained in the open state by the current generated by the thermoelectromotive force from the thermocouple, the safety valve generates heat from the thermocouple. Since the safety valve closes when it reaches a potential that generates a current that cancels the current generated by the electric power, the safety valve driving device can be easily configured.

[0010]

FIG. 1 shows a safety valve 3 for opening and closing a gas supply path, which only keeps the valve open by passing a current through an electromagnetic coil, and a safety valve 3 with a current I1 generated by a thermoelectromotive force generated during combustion. 3, a thermocouple 2 for maintaining the valve open state, a triangular wave power supply 6 for applying a triangular wave voltage E1 to the safety valve 3, and a switching means 1 for applying or cutting off the triangular wave voltage E1 from the triangular wave power supply 6 to the safety valve 3. (Hereinafter referred to as a relay) and an abnormality monitoring device 4 that switches the relay 1 when an abnormality occurs.

In FIGS. 1, 2 and 3, during combustion,
The contact of the relay 1 is open, and the safety valve 3 maintains the open state with the current I1 generated by the thermoelectromotive force from the thermocouple 2. FIG. 2 shows the safety valve 2, the relay 1 and the gas supply path 7 during combustion. The contact of the relay 1 is open and the gas supply path 7 is conductive. When the abnormality monitoring device 4 detects an abnormality, the abnormality monitoring device 4 notifies the microcomputer 5 of the abnormality detection.
The relay drive current I2 is passed through the electromagnetic coil of (1), and the contact of the relay 1 is closed. When the contact of the relay 1 is closed, the triangular wave voltage E1 from the triangular wave power supply 6 is applied to the safety valve 3. When the potential of the triangular wave voltage E1 from the triangular wave power supply applied to the safety valve 3 becomes a potential that cancels out the current I1 generated by the thermoelectromotive force from the thermocouple 2 in the process of rising or falling, the safety valve 3 maintains the open state. As a result, the safety valve 3 is closed, the gas supply path 7 is shut off and the fire is extinguished. FIG.
Is the safety valve 3, relay 1, and gas supply path 7 at that time.
Is shown. The contact of the relay 1 is closed, and the gas supply path 7 is shut off.

The voltage of the triangular wave according to the present invention increases with time and decreases at a certain voltage. Alternatively, it is a voltage waveform that rises after falling first, and the time required for the rising and falling of the voltage does not have to match. When the process of rising and falling or the process of falling and rising is defined as one cycle of the triangular wave voltage, the cycle of the applied triangular wave voltage may be one cycle or more, and may be any cycle. In the course of the rise and fall of the voltage, a part of the constant voltage may be included. For a triangular wave voltage whose voltage starts rising, the rising start voltage and the falling end voltage do not need to match, and for a triangular wave voltage whose voltage starts falling, the falling start voltage and the rising end voltage do not need to match.

[0013]

According to the apparatus of the present invention, the following effects can be obtained.

(1) The triangular wave voltage applied to the safety valve is set to an appropriate value as compared with the conventional configuration in which the current generated by the thermoelectromotive force from the thermocouple is shut off by using a relay to close the safety valve. By doing so, the contact resistance of the relay can be neglected, so that it is inexpensive without being limited by the selection of the relay.

(2) When a triangular wave voltage of one cycle or more is applied, there is a potential that cancels the current generated by the thermoelectromotive force from the thermocouple at least twice when the triangular wave potential rises and falls, so that safety is improved. Is improved.

(3) The safety valve can be reliably closed by properly selecting the triangular waveform of the triangular power supply even with respect to the variation and fluctuation of the current caused by the thermoelectromotive force from the thermocouple, thereby improving the safety.

[Brief description of the drawings]

FIG. 1 is a block diagram of a safety valve driving device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing states of a safety valve and a relay during the combustion.

FIG. 3 is a block diagram showing states of a safety valve and a relay at the time of the automatic fire extinguishing.

FIG. 4 is a block diagram of a conventional safety valve driving device.

FIG. 5 is a block diagram of another conventional electromagnetic valve driving device.

[Explanation of symbols]

 Reference Signs List 1 relay 2 thermocouple 3 safety valve 4 abnormality monitoring device 5 microcomputer 6 triangular wave power supply

Continuation of the front page (56) References JP-A 2-109155 (JP, U) JP-A 41-24933 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23N 5 / Ten

Claims (1)

(57) [Claims] 1. A safety valve for opening and closing a gas supply path that only keeps a valve open by passing a current through an electromagnetic coil.
A thermocouple for maintaining an open state of a safety valve with a current generated by a thermoelectromotive force generated during combustion, a triangular wave power supply for applying a triangular wave voltage to the safety valve, and applying a triangular wave voltage from the triangular wave power supply to the safety valve. and switching means for blocking are more configuration as the abnormality monitoring device for switching the switching means at the time of abnormality, the <br/> Symbol safety valve before by applying at least one cycle of triangular wave voltage from the triangular wave power to the safety valve at the time of abnormality A safety valve drive device characterized by closing the valve.