JPH0531047B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is a method for burning kerosene by taking in room air,
The present invention relates to a control device for a combustion appliance that performs heating by releasing the combustion gas into a room.

BACKGROUND TECHNOLOGY In general, this type of combustion appliance is as shown in Fig. 4.
A burner 3, a hot air fan 4 and its motor 5, and a controller 6 that controls all of these are successively arranged inside the space surrounded by the exterior 1 and the stand 2. The blower motor 5 blows indoor air A. The configuration is such that the mixture is mixed with combustion gas B and discharged as warm air C at an appropriate temperature through a louver 7 to heat the room.

As shown in Fig. 5, the burner 3 includes a vaporizer tube 8 for vaporizing kerosene for combustion, an electromagnetic pump 9 for supplying a fixed amount of kerosene, a burner motor unit 10 for sending combustion air, and an ignition electrode for igniting the vaporized kerosene. 1
1. A flame rod 12 and the like for monitoring the state of the combustion flame D are provided. The circuit of the electromagnetic pump 9 is as shown in FIG. 6, and its operation will be explained below. First, the alternating current generated from the alternating current terminals a and b is converted to direct current by a diode 13, a resistor 14, and a capacitor 16. Replace thyristor 1
9 and 21. During steady state, a voltage is applied to the gate point g through the resistor 20 → semi-fixed resistor 34 → point f → trigger element 23, so that the thyristor 21 is in the ON state by the trigger element 23. However, the thyristor 19 is turned off because there is no signal from the control circuit 6A. Therefore, the capacitor 21a is charged with positive polarity on the e-point side and negative polarity on the f-point side. In this state, the control circuit 6
When the signal from A enters the light emitting diode 33 in the form of a pulse signal, the transistor 26 turns on and hits the gate h, so the thyristor 19 turns on. In this state, the voltage at point e suddenly drops and the charge on the capacitor 21a is transferred from the resistor 22 to e.
Point → Thyristor 19 → Point b → Thyristor 21 → f
Discharge in the point circuit. Therefore, a reverse voltage is momentarily applied to the thyristor 21, causing it to turn off. This time, the capacitor 21 starts to be charged with the point f being positive and the point e being negative, and the voltage of the capacitor 21a increases until the voltage of the trigger element 23 reaches the trigger voltage, and when the trigger is finally triggered, the thyristor 21 is turned on again. do. For this reason, this time,
The charged load of the capacitor 21a goes through a loop of point f -> thyristor 21 -> thyristor 19 -> point e -> resistor 22, and a reverse voltage is applied to the thyristor 19, turning it off. By repeating this, electromagnetic pump 1
8 works. FIG. 7 shows the pulses applied to the electromagnetic pump coil 18, and a indicates the light emitting diode 33 of the pulses emitted from the microcomputer 28.
Its width t ₁ and period d ₁ are determined by the microcomputer 28, and its height h ₁ is determined by the control circuit 6.
Determined by Due to such pulses, a voltage is applied to the electromagnetic pump coil 18 as shown in FIG. That is, when the light emitting diode 33 operates, the electromagnetic pump coil 18 receives b due to the circuit operation as described above.
A pulse with the following waveform is applied. This pulse width t ₂ is while the thyristor 19 is ON,
Specifically, it is determined by the values of the capacitor 21, the resistors 20, 21, the semi-fixed resistor 34, and the trigger voltage _VBO of the trigger element 23. Pulse width d ₂
Like a, is determined by a signal issued from the microcomputer. The pulse height _h2 is determined by the DC voltage between points c and b generated by the voltage in the AC power supply a and b.

Therefore, in the burner 3, oil is supplied to the vaporizer 8 by the operation of the electromagnetic pump 9, the oil is vaporized by the vaporizer 8, and air for combustion is supplied by the burner fan unit 10, and the control circuit 6A commands. The air-fuel ratio becomes appropriate according to the amount of combustion, and proper combustion can be performed.

In this case, since the ON width _t2 of the electromagnetic pump coil 18 varies due to the characteristics of each pump and the constants of the circuit, the flow rate is adjusted one by one by pairing the circuit and pump using the semi-fixed resistor 34. I am doing it.

Problems to be Solved by the Invention As described above, according to the present control circuit, the thyristors 19 and 21, the trigger element 23, the resistors 20 and 2
2. If the characteristics of the variable resistor 34, the capacitor 21a, etc. change even slightly, an abnormality will occur in the operation of the pump 9, which will become dangerous especially when the flow rate increases.

Also, the pulse height of the electromagnetic pump 9 (Fig. 7b)
_h2 ) changes directly depending on the AC power supply voltage, so even if the air volume is not affected by the voltage, for example when the rotation speed of the burner motor is kept constant as is the case recently, the pump is more affected by the voltage. It has the disadvantage that when exposed to heat, it causes a large change in combustion, resulting in poor exhaust gas.

In addition, since the thyristor 19 generally has a self-triggering phenomenon, it may turn on at times other than regular pulses, and even at this time, it has the disadvantage that the oil flow rate increases.
Furthermore, the electromagnetic pump 9 and the complicated control circuit are always paired, and it is always necessary to assemble them in pairs during assembly and service, which is troublesome.

The present invention was made in view of these points.
The purpose is to improve performance, safety, and handling during work.

Means for Solving the Problems In order to achieve the above object, the present invention has a control circuit connected to an AC power source that controls a load group and at the same time sends a signal to an emitter follower type DC constant voltage circuit using transistors. The electromagnetic pump is configured to operate by turning the output voltage of the DC constant voltage circuit ON and OFF.

Effects The present invention has the above configuration, which makes it possible to simplify the configuration of the electromagnetic pump to improve ease of handling, and to improve the configuration by concentrating electronic components on a printed circuit board within the main body. Since the output of the voltage circuit is turned on only when necessary, the output effect is improved and even low-rated components can be used. Furthermore, since the circuit does not have a self-oscillating part using active components such as thyristors, the electromagnetic pump operates only with pulses from the control circuit, and self-oscillation does not occur even when component characteristics deteriorate, making it safe. be.

Embodiment An embodiment of the present invention will be described below based on the drawings. In FIG. 1, an AC power supply 35 applies an AC voltage between terminals a and b. Connected between a and b is a control circuit 6A' mainly including a microcomputer 28', and a load group 32' operated by the control circuit 6A'. A diode 13, a resistor 14, a point C, and a capacitor 16 are connected from a terminal A to a terminal B, and an emitter follower type DC constant voltage circuit 36 including a transistor is connected between points C and B. DC constant voltage circuit 3
Inside the pump 6, a circuit from point c to NPN transistor 37 (collector 38 to emitter 39) to point d to electromagnetic pump 40 to point b constitutes a main circuit.
Base 41 of transistor 37 = between point e and point b
Collector 43 of NPN transistor 42 → emitter 44 = point f → cathode side of Zener diode 45 are connected. There are two resistors 4 between points d and b.
6-Point g--Resistor 47 and diode 48 are connected. A resistor 49 is connected between points d and f. Point g connects the base 50 of transistor 42. On the other hand, a resistor 51 and an emitter 53 and collector 54 of a PNP transistor 52 are connected between points ce and e, and a zener diode 55 is connected between the base (point h) and point c, with the point c side being the cathode. A resistor 57 is connected between points h and b, a collector-emitter of a phototransistor 26 of a photocoupler 25 is connected between points c and h, and a light emitting diode 33 is connected to a control circuit 6A' of a microcomputer 28'. .

The electromagnetic pump 40 has a conventional pump coil 18' connected in series with a resistor 56, which divides the flow rate of the electromagnetic pump into equal parts within the range of variation, and divides the flow rate of the electromagnetic pump into equal parts within the range of variation, and divides the flow rate of the electromagnetic pump into equal parts within the range of the variation. It is constructed by attaching a variable resistor or a variable resistor. That is, in any electromagnetic pump, the flow rate can be uniquely determined as long as the pulses coming from the constant voltage circuit are specified.

In the above configuration, AC power 35 is applied between points a and b. The basic functions of the control circuit 6A' and the load group 32' are completely the same as before. The alternating current voltage between points a and b generates a direct current voltage between points c and b by a diode 13, a resistor 14, and a capacitor 16.
Although this DC voltage contains ripples, it cannot be used as is because it basically reflects the fluctuations in the power supply voltage. Therefore, a constant voltage circuit 36 is used to generate a constant and stable voltage between points d and b.

PNP type transistor 52 and resistors 51, 57,
The circuit of the zener diode 55 is a circuit that always keeps the collector current of the transistor 52 (this is defined as i ₁ ) constant, and the current value i ₁ depends on the zener voltage of the zener diode 55 and the value of the resistor 51. It's decided.

This current i ₁ is the base current i ₂ of the transistor 37 and the collector current of the transistor 42 at the point e.
i Divided into ₃ .

Next, a base current flows through the base 50 of the transistor 42 depending on the g-point potential and the zener voltage of the zener diode 45, and when the g-point potential is high, a large amount of collector current _i3 flows, and when the g-point potential is low, a small amount flows.
Therefore, the base current i ₂ of the transistor 37 is i ₃
Since it is determined by the value of , as i ₃ increases, i ₂ decreases. The potential at point d is the load and base current between points d and b.
Depends on i ₂ and if i ₂ is large, transistor 37
The emitter current _i4 increases, and since the load is constant, the potential at point d increases. When the voltage at point d increases, g
Since the point potential also increases, i ₃ increases and i ₂ decreases.
When i ₂ decreases, i ₄ decreases and therefore the potential at point d becomes lower. Therefore, when the g-point potential also decreases, i ₃ decreases.
i ₂ increases. The above operation is repeated to determine the potential at point d based on the potential at point g. It is also used for correction by the Zener voltage based on the current characteristics of the Zener diode 45 when i ₃ is significantly reduced due to the current flowing to the Zener diode 46 through the resistor 49.

Therefore, as shown in FIG. 2, by connecting a semi-fixed resistor 58 between the base point 50g of the transistor 42 and the resistors 46 and 47 to adjust the potential at point g, the potential at point d can be maintained at an arbitrary constant value. I can do it. In this way, even if there is a fluctuation between the input voltage points c and b, the output voltage d
- It becomes constant between points b. Next, between points ch,
A phototransistor 26 of a photocoupler 28 is connected, which is operated by a signal from a control circuit 6A' mainly operated by a microcomputer 28'. This is connected to the diode 3 by the signal from the microcomputer 28'.
When 3 is on, the transistor 26 is
Since it turns ON, short-circuit between points c and h. Therefore, the base point h of the transistor 52 and the emitter 53 are short-circuited, the collector 54 and the emitter 53 are in an open state, and _i1 becomes 0. Therefore, neither the transistor 37 nor the transistor 42 operates, so the output point d becomes 0. In addition, the signal light emitting diode 3
If 3 is not lit, the transistor 26 is open and the output point d becomes a normal voltage, for example, about 90V. This output point d repeats ON and OFF, and the electromagnetic pump 40 is driven, that is, oil is supplied to the burner 3.

This state is as shown in Figure 3, where a is the characteristic of the signal diode 33 from the microcomputer 28', and b is the voltage waveform supplied to the electromagnetic pump 40. Although the operation is completely opposite, the period is completely Match. That is, the OFF time t ₃ of the light emitting diode 33 and the pump 40
ON time t ₄ , period d ₃ of diode 33 and pump 4
It is exactly the same as the period d ₄ of 0.

Note that the voltage _h4 when the pump 40 is ON remains the same between the output voltage points d and b of the circuit and is always constant, so in order to change the oil flow rate, the ON time of the pump 40, ON voltage, period, etc. Perform one of these, for example, by changing the cycle.

Effects of the Invention As is clear from the above description of the embodiments, since the present invention uses transistors and an emitter follower type DC constant voltage circuit, self-oscillation does not occur, and there is no premature failure. It's safe.

Also, turn on the output of the DC constant voltage circuit itself.
The circuit is much more efficient than constantly outputting a constant voltage to turn it off. Furthermore, even if the power supply voltage fluctuates, the output voltage, that is, the pulse to the pump, does not change at all, so if the rotation of the burner blower fan is detected and controlled, the optimum air-fuel ratio for the burner can be obtained. It becomes like this.

In addition, as mentioned above, the output voltage is constant, so there is no need to install a complicated circuit on the pump as in the past, and it is possible to measure the output of each pump in advance and select the resistance based on this rank. By doing so, there is no need to measure and adjust the resistance value as in the past, making production easier, and the method of division can even improve accuracy.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a combustion control device according to an embodiment of the present invention, Fig. 2 is an explanatory diagram showing the adjustment section of the circuit, Fig. 3 is an explanatory diagram of the pulse waveform, and Fig. 4 is related to the present invention. FIG. 5 is a cross-sectional view of the hot air fan, FIG. 5 is a structural diagram of its burner portion, FIG. 6 is a circuit diagram showing a conventional example, and FIG. 7 is a diagram illustrating its pulse waveform. 6A'... Control circuit, 25... Switching element, 36... DC constant voltage circuit, 37... First transistor, 40... Electromagnetic pump, 42... Third transistor, 45... Zener diode, 51...
...Resistor, 52...Second transistor.

Claims (1)

[Claims] 1 A series circuit of a second transistor and a resistor is connected to the input side collector and base of the first transistor of a DC constant voltage circuit using an emitter follower connection, and a series circuit of a second transistor and a resistor is connected to the base and emitter side of the second transistor by the output from the control circuit. In addition to connecting the operating switching element, the resistance dividing point on the output side of the DC constant voltage circuit is connected to the base of the third transistor, and the collector of the third transistor is connected to the first transistor.
A combustion control device in which a zener diode is connected to the emitter of the transistor base, and an electromagnetic pump that supplies kerosene in pulse form is connected to the output side of the DC constant voltage circuit.