JPH0223973Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a combustion control device for a combustion machine equipped with a vaporizer that vaporizes liquid fuel, such as a vaporizing oil stove.

[Technical background of the invention] Conventionally, for example, as a vaporizing oil stove, the one shown in FIG. 3 is known. That is, this connects the vaporizer heater 3 that heats the vaporizer to the AC power source 1 via the first switch 2, and
An electromagnetic pump drive circuit 8 that drives an electromagnetic pump 7 that supplies kerosene as fuel to a convection fan motor 5, an igniter 6, and a carburetor is connected via the second switch 4. Further, a load control circuit 9 is connected to the AC power source 1. The load control circuit 9 includes an operation switch 10, a thermistor 11 for detecting vaporizer temperature, a first relay 12 for controlling on/off the first switch 2, and a second relay 12 for controlling the first switch 2 on and off.
A second relay 13 is connected to turn on and off the switch 4. Further, the load control circuit 9 is provided with a flame monitoring circuit 9a, and the flame sensor 1
The signal from 4 is being input.

In this device, when the thermistor 11 detects that the temperature of the vaporizer is low, the operation switch 10 is turned on.
When the load control circuit 9 turns on the first relay 1
2 to turn on the first switch 2. This starts energizing the vaporizer heater 3,
The vaporizer is heated. When the vaporizer reaches a desired temperature, the load control circuit 9 operates the second relay 13 to turn on the second switch 4. The electromagnetic pump 7 is operated by the electromagnetic pump drive circuit 8, and kerosene is supplied to the carburetor, and the igniter 6 is operated to ignite the burner section. The flame sensor 1 determines whether the ignition was carried out normally or not.
4 and the flame monitoring circuit 9a, and if the combustion state is normal, the combustion state is maintained and the state shifts to a steady combustion state. During this time, the first switch 2 is turned on and off according to the temperature detected by the thermistor 11, and the temperature of the vaporizer is maintained substantially constant.

In this state, when the operation switch 10 is turned off or the flame monitoring circuit 9a detects an abnormal combustion state, the load control circuit 9 stops the operation of the second relay 13, turns off the second switch 4, and turns off the electromagnetic pump. The power supply to the drive circuit 8 is stopped. In this way, the supply of kerosene to the vaporizer is immediately stopped and fire extinguishing action is performed.

[Problems with the Background Art] However, in this conventional device, if an accident occurs in which the second switch 4 is welded, or if an accident occurs in which the second relay is not turned off due to a failure, the electromagnetic pump drive circuit 8 There was a problem in which the power to the equipment could not be cut off, making it impossible to extinguish the fire even if the situation required it to be extinguished.

[Purpose of the invention] This invention was devised to solve such problems, and even if an accident occurs in which the energization path to the electromagnetic pump drive circuit is not cut off when a fire is extinguished, the electromagnetic pump will continue to operate. The purpose of the present invention is to provide a combustion control device that can reliably stop the engine and ensure safety.

[Summary of the invention] This invention uses a load control circuit to control the second switch on and off to control the supply of electricity to the electromagnetic pump drive circuit, and also to control the oscillation in the electromagnetic pump drive circuit by the load control circuit. The circuit operation is directly controlled to stop.

[Embodiments of the invention] Hereinafter, embodiments of this invention will be described with reference to the drawings.

As shown in FIG.
A vaporizer heater 23 for heating the vaporizer is connected via 2. In addition, an operation is performed to supply kerosene as fuel to the convection fan motor 25, igniter 26, and carburetor through the normally open contact 24 of a second relay, which will be described later, as a second switch to the AC power source 21. Electromagnetic pump drive circuits 28 that drive electromagnetic pumps 27 are connected to each other. Further, a load control circuit 29 is connected to the AC power source 21. The load control circuit 29 includes an operation switch 3.
0, the thermistor 31 for detecting the temperature of the vaporizer, the first and second relays 32 and 33 mentioned above, and the light emitting diode 34 of the photocoupler 34 as a signal transmission means.
D are connected to each other. Further, the load control circuit 29 is provided with a flame monitoring circuit 29a, which receives a signal from a flame sensor 35 that detects the state of the flame in the burner section. When the operation switch 30 is turned on, the load control circuit 29 turns on the thermistor 3.
1 detects the temperature of the vaporizer, and if the temperature has not reached the desired temperature, the first relay 32 is operated to turn on the normally open contact 22, and the temperature of the vaporizer reaches the desired temperature. When the threshold is reached, the operation of the first relay 32 is stopped and its normally open contact 22 is turned off.
Further, when the thermistor 31 detects that the temperature of the carburetor has reached a desired temperature, the load control circuit 29 operates the second relay 33 to turn on the normally open contact 24. Further, the load control circuit 29 turns on the light emitting diode 34D of the photocoupler 34 when the operation switch 30 is turned on, and when the operation switch 30 is turned off,
When an abnormal combustion state is detected by the flame sensor 35 during combustion, the operation of the second relay 33 is stopped. Further, the load control circuit 29 outputs an oscillation stop signal when the operation switch 30 is turned off or when an abnormal combustion state is detected by the flame sensor 35.
The light emitting diode 34D is turned off.

The electromagnetic pump drive circuit 28 is constructed as shown in FIG. In other words, a rectifying diode D ₁ and a resistor R ₁ are connected between the input terminals I ₁ and I ₂ of the AC power supply.
Smoothing capacitor _C1 is connected through. A Zener diode ZD is connected in parallel to the smoothing capacitor _C1 via a resistor _R2 , and a first thyristor is connected via the electromagnetic pump 27.
SCR ₁ is connected in parallel, and a series voltage divider circuit of resistors R ₃ and R ₄ is connected in parallel. An oscillation circuit OSC is connected in parallel to the Zener diode ZD.
The oscillation circuit OSC has a series voltage divider circuit of resistors R ₅ and R ₆ and a series time constant circuit of a variable resistor VR ₁ , a resistor R ₇ , a variable resistor VR ₂ and a capacitor C ₂ connected in parallel to the Zener diode ZD. and its resistance R ₅
and connection point with R ₆ and variable resistor VR ₂ and capacitor C ₂
A capacitor _C3 is connected between the connection point and the gate and anode of the PUT element P. A resistor _R8 is connected between the connection point between the variable resistor _VR2 and the capacitor _C2 and the connection point between the resistors _R3 and _R4 . NPN to capacitor C ₂
A resistor R ₉ is connected between the base and emitter of the transistor Tr, and a phototransistor 34 of the photocoupler 34 is connected in parallel.
and the base of the transistor Tr is connected to the cathode of the Zener diode ZD via a resistor _R10 . The cathode of the PUT element P is connected to the gate of the first thyristor _SCR1 via a resistor _R11 . Note that a capacitor _C4 is connected between the gate and cathode of the first thyristor _SCR1 , and the resistor
A resistor _R12 is connected through _R11 .

The electromagnetic pump 27 includes a variable resistor VR ₃ and a resistor.
A series time constant circuit consisting of R ₁₃ , resistor ₁₄ and capacitor C ₅ is connected in parallel, and a protection diode is connected in parallel.
D ₂ are connected in parallel. The first thyristor SCR ₁ is connected to the second thyristor with the polarity shown through a series circuit of the resistor R ₁₄ and the capacitor C ₅ .
SCR ₂ is connected in parallel. A series circuit of a constant voltage conduction element DI and a resistor _R15 is connected in parallel to the second thyristor SCR ₂ , and the conduction element DI and the resistor are connected in parallel.
The connection point with _R15 is connected to the gate of its thyristor _SCR2 via a resistor _R15 . A diode D ₃ is connected between the gate and cathode of the second thyristor SCR ₂ in the illustrated polarity, and a diode D ₄ is connected in parallel to the constant voltage conduction element DI.

This electromagnetic pump drive circuit 28 is an oscillation circuit OSC
When the phototransistor 34T is turned on, the transistor Tr is turned off, thereby making it possible to charge the capacitor _C2 . That is, the oscillation circuit OSC becomes capable of oscillation. In this state, the capacitor C ₂ is charged, and when the charging voltage becomes higher than the voltage divided by the resistors R ₅ and R ₆ , the PUT element P becomes conductive, thereby causing the first
thyristor SCR ₁ becomes conductive. In this way, current flows through the electromagnetic pump 27. variable resistance VR ₃ at the same time,
Capacitor _C5 is charged via resistors _R13 and _R14 . When the charging voltage of the capacitor _C5 reaches the breakover voltage of the constant voltage conduction element DI, the conduction element DI becomes conductive and the second thyristor
SCR ₂ becomes conductive. When the second thyristor SCR ₂ conducts, the charge in the capacitor C ₅ is instantly discharged,
Also, the current flowing through the electromagnetic pump 27 is also connected to the capacitor.
Second thyristor SCR ₂ via C ₅ and resistor R ₁₄
flows to As a result, the current flowing through the first thyristor SCR ₁ becomes lower than the current that can maintain its conduction, and the first thyristor SCR ₁ becomes non-conductive. Further, the second thyristor SCR ₂ also becomes non-conductive because the resistance values of the variable resistor VR ₃ and the resistor R ₁₃ are large and a current that is large enough to maintain the conductive state does not flow therethrough. In this way, according to the oscillation period of the oscillation circuit OSC, the first thyristor SCR ₁ is controlled to conduct for a certain period of time determined by the time constant circuit of the variable resistor VR ₃ , resistors R ₁₃ , R ₁₄ and capacitor C ₅ , and the electromagnetic pump 27 is energized. Therefore, in this electromagnetic pump drive circuit 28, by changing the oscillation period of the oscillation circuit OSC and the conduction period of the first thyristor SCR ₁ , the conduction content to the electromagnetic pump 27 can be changed. The amount of kerosene supplied can be varied.

In the apparatus according to the embodiment of the present invention having such a configuration, the operation switch 30 is turned on when the temperature of the vaporizer is low.
When the normally open contact 22 is turned on by the first relay 32, energization to the carburetor heater 23 is started. The vaporizer is thus heated.
In addition, the light emitting diode 34D of the photocoupler 34
is operated. Thereafter, when the temperature of the vaporizer reaches the desired temperature, the second relay 33 is operated and its normally open contact 24 is turned on. In this way, energization of the convection fan motor 25, igniter 26, and electromagnetic pump drive circuit 28 is started. However,
Supply of kerosene to the vaporizer is started, and ignition operation is performed by the igniter 26 in the burner section. Ignition takes place in this way, and eventually a steady combustion operation begins.

In this state, when the operation switch 30 is turned off or an abnormal state of combustion is detected by the flame sensor 35 and fire extinguishing control is started by the load control circuit 29, the operation of the second relay 33 is stopped and the operation of the second relay 33 is stopped. The operation of the light emitting diode 34D is stopped. As a result, power supply to the electromagnetic pump drive circuit 28 is stopped, and the oscillation circuit OSC in the drive circuit 28 becomes incapable of oscillating due to the off state of the phototransistor 34T.

Therefore, even if an accident occurs such as the normally open contact 24 welding or the second relay failing and the normally open contact 24 not turning off, the electromagnetic pump drive circuit 28 will continue to be energized, but oscillation will not occur. Since the circuit OSC is rendered inoperable, there is no problem in which the first thyristor SCR ₁ is turned on and the electromagnetic pump 27 is energized. In this way, even if the power supply to the electromagnetic pump drive circuit 28 is not cut off when the fire is extinguished, the operation of the electromagnetic pump 27 can be reliably stopped, and safety can be improved.

In the above embodiments, the phototransistor of the photocoupler is provided in the oscillation circuit of the electromagnetic pump drive circuit, and the light emitting diode of the photocoupler is controlled by the load control circuit to control the operation of the oscillation circuit. The present invention is not limited to this, and a relay may be used instead of a photocoupler.

[Effects of the invention] As detailed above, according to this invention, even if an accident occurs in which the energization path to the electromagnetic pump drive circuit is not cut off when a fire is extinguished, the operation of the electromagnetic pump can be reliably stopped. It is possible to provide a combustion control device that can ensure safety.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing an embodiment of this invention, Figure 2 is a circuit diagram showing an embodiment of this invention.
The figure is a specific circuit diagram of the electromagnetic pump drive circuit in the same embodiment, and FIG. 3 is a circuit diagram showing a conventional example. 21... AC power supply, 22... Normally open contact of the first relay (first switch), 23... Carburizer heater, 24... Normally open contact of the second relay (second switch), 26 ...Igniter, 27...Electromagnetic pump,
28... Electromagnetic pump drive circuit, 29... Load control circuit, 31... Carburetor temperature detection thermistor, 3
4...Photocoupler, OSC...Oscillation circuit, SCR ₁ ,
SCR ₂ ...thyristor.

Claims (1)

[Scope of utility model registration request] a power source; a carburetor heater for heating a vaporizer connected to the power source via a first switch; and an electromagnetic pump for supplying liquid fuel to the vaporizer connected to the power source via a second switch. an electromagnetic pump drive circuit having an oscillation circuit that operates intermittently, an igniter that ignites the burner section, and on/off control of the first switch to maintain the temperature of the vaporizer at approximately a predetermined temperature. and when the temperature of the vaporizer reaches a predetermined temperature, the second switch is turned on to supply fuel to the vaporizer and ignite the igniter, and when extinguishing,
a load control circuit that turns off the first and second switches and outputs an oscillation stop signal; and a load control circuit that transmits the oscillation stop signal output from the load control circuit to the oscillation circuit to stop its operation. 2
1. A combustion control device comprising: signal transmission means for forcibly stopping the operation of the oscillation circuit even if the switch is not controlled to be off.