JPS5838289Y2 - Safety circuit reset device in combustion control equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a reset device for a safety circuit of a combustion control device in a hot water boiler or the like.

Generally, burner safety is ensured by introducing a keep relay into combustion control devices such as boilers, which cuts off power to the device in the event of an abnormality such as burner non-ignition, and maintains the cut-off state even during a power outage. However, when reusing the relay, a reset device is required to release the kept state of the relay.

The present invention relates to the configuration of this reset device, and the reset circuit is made extremely simple by using a normal burner circuit configuration, and one embodiment shown in the drawings will be specifically explained below.

1 is an AC power source, 2 is a burner circuit whose energization is controlled by a control circuit to be described later, and the circuit 2 includes a fan motor, an igniter, an electromagnetic pump, etc.

3 is a coupling trunk, 4 is a rectifier, 5 is a smoothing capacitor, and 6 is a dummy resistor.

7 is a control circuit, and the circuit 7 includes a thermo circuit, a bripurge circuit, a flame detection circuit, a safety operation circuit, etc. The thermo circuit detects the temperature of hot water in the boiler with a thermistor and controls the burner circuit 2. The pre-purge circuit delays the operation of the electromagnetic pump for a certain period of time using a timer circuit at startup.
The flame detection circuit detects the burner flame with a sensor element such as CDS, and if the burner does not ignite, it operates a safety operation circuit and outputs a safety operation signal from the safety operation circuit.

Reference numeral 8 denotes a safety circuit, which includes a keep relay 9, a normally closed contact 11 of a push button 10, and a transistor 12 which becomes conductive in response to an output signal from the aforementioned safety operation circuit.

13 is a normally closed relay contact of the keep relay 9 connected to the power line from the smoothing capacitor 5, and 14 is a diode placed in the power line between the capacitor 5 and the resistor 6.

Further, the power supply line of the relay contact 13 and the negative electrode side of the relay 9 are connected via the normally open contact 15 of the push button 10.

16 is a power switch. The present invention has the above-mentioned configuration, and when the power switch 16 is closed, the control circuit 7 is energized, and after a pre-purge in which only the fan motor and igniter operate for a certain period of time, the electromagnetic pump is activated to perform the ignition operation. If ignition is detected, the operation of the igniter is stopped and a steady combustion state is maintained thereafter.

However, if ignition does not occur, the safety operation circuit operates and outputs a safety operation signal, transistor 12 becomes conductive, and therefore keep relay 9 is energized and relay contact 13 is activated.
is activated, the power supply to the control circuit 7 is cut off, and the burner circuit 2 is kept in an inoperable state.

By the way, the operation of the keep relay 9 continues even if the power is re-energized after a power outage, but when it is to be used again, the push button 10 can be pressed.

Then the current flows through the power switch 16 - contact 15 - relay 9 -
The current flows through the resistor 6, and therefore a reverse voltage is applied to the relay 9, releasing the kept state, and the relay contact 13 is returned to the normally closed state, making it possible to reuse it.

The present invention performs the above-mentioned functions, and its feature lies in the use of a conventional burner circuit configuration such as a capacitor 5 and a dummy resistor 6.

That is, the capacitor 5 can make the operation of the relay 9 more reliable by energizing the relay 9 with a discharge current for a certain period of time after the keep relay 9 is activated, and the resistor 6 can make the operation of the relay 9 more reliable. It is also used as a current limiting resistor.

Therefore, according to the present invention, the circuit configuration of the reset device is extremely simple, the number of parts such as contacts is small, the device is inexpensive, and it has the advantage that a keep relay can be easily added to a wide range of general combustion control devices. It is something that you have.

[Brief explanation of the drawing]

The drawing is an electrical circuit diagram showing an embodiment of the present invention. 2... Burner circuit, 5... Capacitor, 6... Resistor, 7... Control circuit, 9
...Keep relay, 10...Push button, 1
1... Normally closed contact, 12... Transistor, 13... Roux contact, 14... Diode, 15... Normally open contact .

Claims (1)

[Scope of utility model registration request] The normally closed loop of the keep relay, which is energized via the normally closed contact of the push button by the transistor passing through the safety operation circuit, is connected to the power supply line through the capacitor and resistor connected between the power supply in the front stage of the control circuit that controls the burner circuit. At the same time, a diode is arranged between the capacitor and the resistor, and the safety circuit in the combustion control device is reset by connecting the power supply line from the relay contact to the negative side of the relay via the normally open contact of the push button. Device.