JPS5869325A - Combustion controlling equipment - Google Patents

Abstract

PURPOSE:To improve the safety in case of the failure of flame detection circuit by a method wherein a timing hour for discriminating the operation of the flame detection circuit is provided in a safety timer circuit and, when the flame detection circuit outputs a flame detection signal, the operation of a burner is brought to a standstill. CONSTITUTION:During the safety timer circuit 20 is timing the time t1 (about 2sec) after the power supply is turned on in accordance with the starting operation procedure, transistors (Tr) 31 and 35 are OFF and a thyristor 39 is also OFF and the anode voltage is at a high level state. Under such a situation, if a failure occurs in the flame detection circuit, and the output of a comparator 55 happens to be the high level, a Tr 73 is ON, and Tr 71 and 81 are kept OFF, resulting in prohibiting the opening of solenoid valves 12 and 13 in a gas pipe. Furthermore, because a Tr 82 is turned ON, even when the output of the safety timer circuit 20 happens to be the high level after the elapse of the time t1, the OFF state of the Tr 31 is kept unchanged and as well as the ON state of the Tr 73 remains also unchanged, resulting in keeping the standstill state in the operation of the equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a combustion control device for a combustion machine. Conventionally, for example, in a gas combustion machine used for heating during hot water supply such as a hot water heater, as shown in %1. In other words, when the power is turned on by turning on the operation switch, the safety timer circuit 1 is activated, which turns on the transistor 2 and turns on the igniter transformer 3t.
And the first electromagnetic valve coil 46 is energized. In this way, the pyrobuttono4-nahe gas is supplied, and when the topana is ignited, the flame detection circuit 5 turns on the transistor 6, and the second electromagnetic valve coil 1 is turned on. Then, the flame of the pilot burner ignites the main part and starts combustion. In this case, at the same time as the transistor is turned on, transistor 2 is forcibly turned off, and the igniter transformer is turned off. 3t is cut off, but the first solenoid valve coil 4 continues to be energized by turning on the transistor σ, and gas supply to Topana and the main burner continues. When the ignition of the tonomana is not completed even after the circuit measures a certain period of time, the transistor 2 is turned off and combustion is stopped. This ensures safety against any abnormality in which ignition is not completed.

By the way, in such a combustion control device, if some kind of failure occurs in the flame detection circuit 5) and the transistor 8 is turned on when the power is turned on, the first and second solenoid valves open simultaneously, so a large amount of gas is released. 9. There is a risk of explosion or flames if released all at once.

This invention was made in view of the above circumstances,
The purpose is to provide a combustion control device with excellent safety that can prevent accidents caused by failure of the flame detection circuit.

An embodiment of the present invention will be described below with reference to the drawings.

In the sg2 diagram, 10 is a main burner, and this main burner 10 is communicated with a gas supply source via a gas pipe 11 @And in the middle of the gas pipe 11 is a first electromagnetic valve which is a fuel supply device. 12 and g2 solenoid valves 11 are arranged in sequence, and the gas pipe 11 between the first solenoid valve 12 and the second solenoid valve 13 is located near the main burner 10.
It is communicated with the pilot burner 14.

In addition, there is an igniter 15 near Topana 14.
and a flame detection electrode 16 are arranged. This flame detection electrode 16 is connected to one end of the secondary coil of the transformer 170,
The other end of the secondary coil is grounded. That is, when the flame detection electrode 16 is hit by the flame of the Mayafus 10 or the pyro or Topana 14, conduction occurs between the flame detection electrode 16 and the main burner 10 or between the flame detection electrode 16 and the Noyai D or Topana 14. It is supposed to be done.

On the other hand, 20 is a safety timer circuit, which is connected to the power supply line Eats and the ground line L. This safety timer circuit 20 includes a resistor 21. Resistor 22°; voltage obtained at the connection point M based on the time constant of capacitor 230 and resistor 24 (resistance value Rt) * - resistor z5 (resistance value R,) # capacitor 26
A comparator 21 compares the voltage obtained at the connection point B based on the time constant of . In this case, as shown in FIG. 3, the voltage obtained at the connection point M increases exponentially, whereas the voltage at the connection point B becomes the voltage and then increases with a predetermined time constant. In this way, the output of the comparator 21 maintains a low level state for 11 hours, for example, 2 seconds from the start of one energization, then becomes a high level for 13 hours, for example, 20 seconds, and then maintains a low level state.

One end of the transformer 1st of the igniter 15 is connected to the power supply line L34, and the other end of the transformer l1it is connected to the ground line L through the collector-emitter of the NPN transistor 31. Furthermore, the power supply line LI4 is connected to the drive coil I of the first electromagnetic valve 12.
One end of the drive coil 12 is connected to the transistor 31 through a diode 32 in the forward direction.
connected to the collector of The pace of the transistor 31 is connected to the output terminal of the safety timer circuit 20 (the output terminal of the comparator 21) 4C via the Zener diode 11, and the connection point between the output terminal and the Zener diode 33 is connected via the resistor 14. It is connected to the power supply line Lus.

Also, between the power supply line Lll and the ground line L,
When a series circuit of resistors set and sr is connected between the emitter, the collector and the emitter of the PNP transistor 35, (
, a series circuit of a resistor 38 and a thyristor SS is connected. The transistor 350 pace is connected to the collector of the transistor 31 through the resistor 40. The dirt terminal of the thyristor 3t is connected to the connection point between the resistors 36 and 31.

Furthermore, 150 is a flame detection circuit, which is configured as follows. The main burner 10 is connected to the non-inverting input terminals (+) of the comparators 54 and 55 through resistors 51 and 55, respectively, and the resistors 51 and 5.
A capacitor 5C is connected between the interconnection point of the resistor 52 and the diode 53 and the ground line L. A capacitor 51 is connected between the interconnection point of the resistor 52 and the diode 53 and the ground line L. Then, the power line L1m and the ground line L・
A series circuit of resistors sH and sg and a resistor 60 are connected between
．． 61 series circuits are connected respectively・Resistors 58 and 5
The connection point with resistor 9 is connected to the non-inverting input terminal (+) of comparator 54.55 through resistor 62, and the connection point of resistor 60 and 61 is connected to the inverting input terminal (-) of comparator 54.55.
). In this way, when a flame occurs in the main burner 10 or the top burner 14, conduction occurs between the flame detection electrode 16 and the main burner 10 or between the flame detection electrode 16 and the top burner 14, and the resistance 5
A direct current flows through the 1.degree.

The other end of the drive coil 12e of the first electromagnetic valve 12 is connected to the ground line L@ via the collector of the NPN transistor 11, and the base of the transistor 11 is connected to the flame detection circuit 50. comparator 54 in
connected to the output end of the Moreover, the output terminal of this comparator 54 is.

It is connected to the power line Lll through a resistor 12, and is connected to the ground line L through the collector, construction, and terminal of the NPN type Langistav 3. The base of this transistor 13 is connected to the anode of the thyristor 39 via a Zener diode 74.

Furthermore, a PNP type transistor I is connected to the power supply line L34.
The second solenoid valve 1 is connected between the emitter and collector of II.
3 drive coil °134! One end of the drive coil 1jle is connected, and the other end of the drive coil 1jle is connected to the ground line L through the collector of the NPN transistor 82. The base of the transis-11 is connected to the collector of the transistor 11 via a resistor 83. The flame detection circuit 5 is connected to the transistor 120' through the resistor 84.
The output end of the comparator 55 is connected to the power supply line L1m via the resistor 85.
It is also connected to the anode of the thyristor 39 via a resistor 86. Further, the collector of the transistor or transistor 82 is connected to the output terminal of the safety timer circuit 20 via the diode 81 in the opposite direction.

Next, we will explain the operation in the above configuration. When the operation switch (not shown) is turned on and the power is turned on, the safety timer circuit 20 is activated and the transistor 31 is turned on after 11 hours (2 seconds). do. Then, the igniter 15 is activated, and the first electromagnetic valve 12 is opened, and the fs ejected from the /arm pilot 14 is ignited by the igniter 15, and the /4 pilot/arm 14 is ignited. Then, the comparators 54 and 55 in the flame detection circuit 50
The output of transistor 71 # Jl becomes high level.
2 turns on. When the transistor 11 is turned on, a new energizing path for the drive coil 12@ is secured, and the @1 solenoid valve 12 continues to be open regardless of the time measured by the safety timer circuit 200. Further, when the transistor 71 is turned on, the transistor 81 is also turned on, and this transistor I
II and the transistor 82 is turned on, the second electromagnetic valve 11 is opened. Thus, Notai 4, Topana 1
The main burner 1a is ignited by the flame No. 4, and a load such as a water heat exchanger is heated.

By the way, when the power is turned on based on the operation start operation, when the 916 safety timer circuit 20 is counting 11 hours, the transistor 31 and MS are turned off and the thyristor 3# is also turned off, and the anode potential of the thyristor 1t is However, at this time, the flame detection circuit 5 reaches a high level state.
When the output of the comparator 55 goes to a high level (flame detection signal) due to some kind of failure in the
L % This maintains the off state of the transistor '11.111, and the first and Wc2 solenoid valves J j ,
Opening of JJ' is prohibited. In this case, since the transistor 11 is turned on when the flame detection signal is output, even if the output of the safety timer circuit 20 becomes high level 11 hours later, the transistor 31. continues to be off,
Therefore, the transistor 130 continues to be on, and the operation is stopped.

In this way, the safety timer circuit 0 is provided with a measuring time t1 for determining the operation of the flame detection circuit, and when the flame detection circuit 50 outputs a flame detection signal within this 11 hours, it is determined that the flame detection circuit 50 is malfunctioning. Since the operation of the combustion machine is stopped, it is possible to prevent accidents such as explosions and fires.◎ This invention is not limited to the above embodiments, and may be applied within the scope of the invention without changing the gist. Of course, various modifications can be made.

As described above, according to this invention, the safety timer circuit is provided with a timing time for determining the operation of the flame detection circuit, and when the flame detection circuit outputs a flame detection signal within the 11 hours, the operation of the combustion machine is stopped. As a result, it is possible to provide a combustion control device with excellent safety that can prevent accidents caused by failure of the flame detection circuit.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of the conventional technology, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3 is a diagram for explaining the operation of the safety tie 1 circuit. Burna,
12...Fuel supply device (11th E magnetic valve), 13...
Fuel supply device (@2 solenoid valve), 14... / power burner, 15... igniter, 20... safety timer circuit, 50... flame detection circuit O

Claims (1)

[Claims] In a combustion machine in which fuel is supplied by a fuel supply device, a burner is ignited by an igniter, and a load is heated by the flame of the 1. Operate the igniter and check the operating status of the igniter. a safety timer circuit that maintains the time; a flame detection circuit that detects the flame of the burner and controls the #i fuel supply device according to the detection result; and the safety timer circuit that operates at t1.
A combustion control device comprising means for stopping operation when the flame detection circuit outputs a flame detection signal during time measurement.