JPH0223780B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion control device for, for example, an open hot air heater.

2. Description of the Related Art Conventionally, there is a combustion control device for an open type hot air heater, for example, as shown in FIG.

The commercial power supply 1 includes a control circuit 4 that monitors relay control and ignition status of each part via self-holding switches (non-lock switch 2 and lock switch 3).
and a diode bridge 5 are connected to each other.

Lock switch 3 and non-lock switch 2 are interlocking contacts in the self-holding switch, and both are ON when the self-holding switch is pushed in.
Then, the power supply 1 is supplied to the control circuit 4, and the control circuit 4 thereby turns on the relay contact 6 connected in parallel to the non-lock switch 2. after that,
Even if the self-holding switch is released and the non-lock switch 2 is turned off, the power supply 1 continues to be supplied to the control circuit 4 due to the relay contact 6 being turned on. That is, it becomes a self-holding state. Further, a convection blower 9 and an ignition transformer 10 are connected to the commercial power source 1 via relay contacts 7 and 8 which are kept closed by the control circuit 4 when the self-holding switch is closed, while a diode bridge 5 is connected to a fuel supply solenoid valve 12 via a relay contact 11 which is controlled in the same way as the relay contact. A delay thermostat 13 that opens and closes depending on the temperature of a combustion tube (not shown) is connected in parallel to the relay contact 7, and operates the convection blower 9 for a predetermined period of time even after the lock switch 3 is opened.

In this configuration, the relay contact 7 that controls on/off of the convection blower 9 is further provided with a delay that operates the convection blower 9 for a predetermined period of time in order to quickly cool down the combustion tube for safety purposes even after combustion has stopped. Since the thermostats 13 are provided in parallel, the cost is increased due to the expensive delay thermostat.

The present invention has been made in view of the above points, and utilizes relay contacts that are opened and closed by a self-holding switch for combustion control, and by simply providing a relatively inexpensive photo coupler and a timer circuit, the self-holding switch can be set up. This achieves blower control that operates when closed and remains operational for a predetermined period of time even when opened.

That is, the combustion control device includes a photocoupler that becomes non-conductive when the self-holding switch opens, and a timer circuit that releases the timed operation based on the non-conduction of the photocoupler and controls the relay contact to open after a predetermined period of time has elapsed. It is.

An embodiment of the present invention will be described below with reference to FIG. Incidentally, the same elements as those in the conventional example are given the same reference numerals and the explanation thereof will be omitted.

In the figure, 21 is a relay contact whose closing is controlled by a control circuit 4, which will be described later, based on the closing of the non-lock switch 2 of the self-holding switch, which is connected in parallel to the non-lock switch 2 and in series with the convection blower 9. has been done. 22 is a resistor, and 23 is a light emitting element, which constitutes a photocoupler together with a phototransistor (not shown) provided in a control circuit 24, which will be described later. 24 is a control circuit that opens and closes the relay contacts 8 and 11 by opening and closing the self-holding switch, and controls the closing of the relay contact 21 by closing the self-holding switch, and also monitors the ignition state; 25 is a control circuit that connects the light emitting element 23; A timed operation is started by the phototransistor, which turns off when the energization stops;
This is a timer circuit that controls opening of the relay contact 21 after a predetermined period of time has elapsed. Both these circuits 24, 25
are connected in parallel to the convection blower 9, respectively.

Next, the action will be explained.

When the self-holding switches (non-lock switch 2 and lock switch 3) are closed, the control circuit 24
Power is supplied to the relay contacts 21, 8, and 11 to close them, while power is supplied to the light emitting element 23 via the diode bridge 5 and the phototransistor of the control circuit 24 is turned on. Relay contact 21,
When 8 and 11 are closed, the convection blower 9, ignition transformer 10, and solenoid valve 12 start operating, and combustion air and fuel are delivered to the burner section (not shown) in the combustion cylinder.
is supplied and ignited.

When the combustion gas is discharged into the room due to ignition and the room becomes warm, and the self-holding switch (lock switch 3) is opened, the control circuit 24 opens the relay contacts 8 and 11, stopping combustion, and the current to the light emitting element 23 is stopped. However, when the current to the light emitting element 23 is cut off, the internal phototransistor is turned off, the timer circuit 25 starts a timed operation, and controls the relay contact 21 to open after a predetermined period of time has elapsed. . That is, even if the self-holding switch is opened, power continues to be supplied to both the convection blower 9 and the control circuit 24 for a predetermined time, and only after the predetermined time has passed, the relay contact 21 is opened and the convection blower 9 is turned off. Then, power to the control circuit 24 is cut off. It goes without saying that the predetermined time of the timer circuit 25 is set to a time sufficient to cool the combustion cylinder.

As explained above, the present invention includes a self-holding switch for combustion control, a relay contact, a control circuit that closes the relay contact based on the closing of the self-holding switch, and a control circuit that closes the relay contact based on the closing of the self-holding switch. In a combustion control device equipped with an operating blower,
The structure includes a photocoupler that becomes non-conductive when the self-holding switch is opened, and a timer circuit that starts a timed operation based on the non-conduction of the photocoupler and controls the relay contact to open after a predetermined period of time has elapsed. By using an inexpensive photocoupler and timer element, the blower can be operated continuously for a predetermined period of time even after combustion has stopped, and the combustion tube can be cooled quickly without the need for an expensive delay thermostat as in the past. .

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a conventional combustion control device for an open type warm air heater, and FIG. 2 is a circuit diagram of a combustion control device for an open type warm air heater, which is an embodiment of the present invention. 2... Non-lock switch, 3... Lock switch, 8, 11, 21... Relay contact, 9... Convection blower, 10... Ignition transformer, 12... Solenoid valve, 23
...Light emitting element, 24...Control circuit, 25...Timer circuit.

Claims (1)

[Claims] 1. A combustion system comprising a self-holding switch for combustion control, a relay contact, a control circuit that closes the relay contact based on the closing of the self-holding switch, and a blower that operates when the relay contact is closed. The control device is provided with a photocoupler that becomes non-conductive when the self-holding switch is opened, and a timer circuit that starts a timed operation based on the non-conduction of the photocoupler and controls the relay contact to open after a predetermined period of time has elapsed. A combustion control device characterized by: