JPS6130039Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion control device having a prepurge time.

The longer the pre-purge time, the more the risk of explosion and ignition is reduced, but the so-called start-up characteristics of the device deteriorate. Therefore, in order to make effective use of the limited pre-purge time, it is sufficient to rotate the combustion fan strongly, but if it is possible to rotate the combustion fan between strong and weak rotation, it is possible to switch between these rotations in terms of time and temperature. need to be controlled. The problem here is that combustion is stopped or interrupted while the thermo circuit for temperature control sets the fan at low rotation, and when re-combustion is started, pre-purge is performed at low rotation.

In this invention, the thermo circuit is stopped during the pre-purge time, and the fan is made to rotate strongly during that time.The diagram will be explained below using a gas hot air heater as an example. .

Reference numeral 1 denotes a commercial power supply, and a switch 2 is connected in series with the switch 2, which is connected to a switch that opens and closes the gas supply path. A fan 3 for discharging exhaust air simultaneously with circulating room air and a power transformer 4 are connected in parallel in order, and an ignition device 6 is connected in parallel to the rear stage of the transformer 4 via an ignition relay contact 5. is connected to the first solenoid valve 8 for the first burner via the gas supply relay contact 7.
are connected in parallel, and a second solenoid valve 1 for the second burner is connected to the first solenoid valve 8 via a temperature control relay contact 9.
0 are connected in parallel. Further, 11 is a speed adjustment relay contact connected in series with the fan 3, and its normally closed contact 12 is connected to the strong rotation tap of the fan 3, and its normally open contact 13 is connected to the weak rotation tap. . Reference numeral 14 denotes a delay thermoswitch connected in parallel to the hot air heater 2, which is disposed in a part of the body of the warm air heater, and is heated and closed during use, and remains closed for a while even after the use is stopped. Incidentally, the first solenoid valve 8 is disposed downstream of the valve, and the first solenoid valve 8 is
In addition to supplying gas to the burner, the second solenoid valve 10 is further arranged in a branch path from downstream of the valve to the second burner. Further, the ignition electrode of the ignition device 6 and the detection electrode of a flame detection circuit, which will be described later, are located close to the first burner.

A full-wave rectifier circuit 1 is installed in the secondary winding of the power transformer 4.
5 is connected, and a constant voltage circuit 16 and a power supply circuit 17 are connected in this order at the subsequent stage. Constant voltage circuit 16
A pre-purge timer circuit 18 and a safety timer circuit 19 are connected in parallel to each other, and an ignition drive circuit 2 that drives an ignition relay is downstream of the power supply circuit 17.
0. The combustion control section includes a solenoid valve drive circuit 21 that drives a gas supply relay, a flame detection circuit 22, a room thermo circuit 24 that drives a temperature adjustment relay and a speed adjustment relay according to the temperature sensed by the room temperature thermometer 23. It is connected as . 25 is a variable resistor for adjusting the sensing temperature.

The prepurge time by the prepurge timer circuit 18 is set to approximately 5 seconds, and the safety timer time by the safety timer circuit 19 is set to approximately 30 seconds, and the output of the prepurge timer and the safety timer are set to approximately 5 seconds.
6, and its OR output is input to the power supply circuit 17. The prepurge timer output is high only during the prepurge time, and the safety timer output is low during the safety timer time.
Therefore, the power supply circuit 17 is configured not to supply power to the combustion control section after the pre-purge time and the safety timer time have elapsed.

When the flame detection circuit 22 detects the flame of the first burner, it applies the detection output to the electromagnetic valve drive circuit 21, the ignition drive circuit 20, and the safety timer circuit 19,
The gas supply relay continues to be driven, the ignition relay is stopped, and the timer drive of the safety timer circuit 19 is interrupted to continue the resistance output. This safety timer circuit 19 reverses to high output after a predetermined time when there is no flame detection output due to misfire, ignition error, etc.
The OR output causes the power supply circuit 17 to stop supplying power.

Next, the operation of the present invention will be described. First, the pot is opened and closed, and the pot switch 2 is linked and closed. Then, the prepurge timer circuit 18 and the safety timer circuit 19 start timer operation, apply high output and low output respectively to the OR gate 26, and stop the power supply by the power supply circuit 17 by the OR output. Therefore, the room thermo circuit 24
Since the operation of the speed adjustment relay contact 11 is stopped, the fan 3 receives power from the normally closed contact 12 and rotates strongly, thereby effectively performing pre-purge. When this pre-purge time has elapsed, the pre-purge timer output is reversed to a low output, so the OR output becomes a low output, and the power supply circuit 17 starts supplying power to the combustion control section. In this way, the ignition relay contact 5 and the gas supply relay contact 7 are closed, and the speed adjustment relay contact 11 and the temperature adjustment relay contact 9 are connected to the room thermometer circuit 24 according to the sensing state of the room temperature thermometer 23.
It is activated or deactivated by Therefore, if the room temperature is lower than the set temperature, the fan 3 continues to rotate strongly with the normally closed contact 12 closed, and the temperature adjustment relay contact 9 closes. As a result, gas is supplied to the first and second burners, the ignition device 6 continuously discharges sparks, and the fan 3 is rotating strongly. When the first burner is ignited and the second burner is also ignited, the combustion exhaust gas and circulating room air are discharged by the fan 3 as hot air. Also, delay thermo switch 1
4 is heated and closed, and the room temperature thermometer 23 is sensing the room temperature. The combustion flame of the first burner is detected by the flame detection circuit 22, and the detection output stops the timer operation of the safety timer circuit 19, causing the OR output to continue at a low output, and the power supply circuit 17 continues to supply power. Further, the solenoid valve drive circuit 21 continues to operate the gas supply relay contact 7, and the ignition drive circuit 20 stops the ignition relay contact 5, thereby stopping the ignition device 6. In the temperature sensing state by the room temperature thermometer 23, when the room temperature exceeds the set temperature, the room thermometer circuit 24 switches the speed adjustment relay contact 11 to the normally open contact 13, opens the temperature adjustment relay contact 9, and turns on the second electromagnetic Close the valve 10 to extinguish the second burner. Incidentally, the set temperature is appropriately adjusted using a variable resistor 25.

When the first burner is extinguished due to ignition error or wind after ignition, the flame detection circuit 2
There is no detection output from 2, and the safety timer circuit 19
The timer operation is performed, and the OR output of the OR gate 26 causes the power supply circuit 17 to stop supplying power to the combustion control section. Therefore, the gas supply relay contact 7, the ignition relay contact 5, and the temperature adjustment relay contact 9 are opened, and the speed adjustment relay contact 11 closes the normally closed contact 12. As a result, since the delay thermoswitch 14 is closed and the gas switch 2 is closed, the fan 3 rotates strongly to expel raw gas and the like.

When the combustion switch 2 is opened to stop use after normal combustion, the fan 3 rotates strongly while the delay thermoswitch 14 is closed to perform a so-called post purge. Then, when the aircraft cools down and the delay thermo switch 14 opens, the post purge ends, and the speed adjustment relay contact 11 becomes the normally closed contact 1.
2 is closed and waiting.

In this way, the combustion control device according to the present invention has strong
The fan, which can be rotated at low speed, is normally set to rotate at high speed, and the room thermo circuit, which rotates the fan at high or low speed depending on the room temperature, is not supplied with power during the pre-purge time, so the fan can be rotated at high speed during the pre-purge time. Prepurge can be performed in a short period of time by strong rotation, and the speed of the fan can be controlled according to the room temperature, and a special timer mechanism dedicated to the fan can also be used in the prepurge timer circuit.

[Brief explanation of the drawing]

The figure is an electrical circuit diagram of a combustion control device according to the present invention. 3...Fan, 11...Speed adjustment relay contact, 12...Normally closed contact, 17...Power supply circuit, 18
... Prepurge timer circuit, 19 ... Safety timer circuit, 22 ... Flame detection circuit, 24 ... Room thermometer circuit, 23 ... Room temperature thermometer.

Claims (1)

[Scope of utility model registration request] A combustion fan has a tap for switching between strong and weak rotation, the normally closed contact of the relay is connected to the tap for strong rotation, and the normally open contact of the relay is connected to the tap for weak rotation, and A thermo circuit that controls the relay by comparing the temperature with a set temperature, a pre-purge timer circuit that sets the pre-purge time, and a timer output from the pre-purge timer circuit to the thermo circuit and combustion control section such as fuel supply. A combustion control device consisting of a power supply circuit that stops power supply for the pre-purge time.