JPS6383519A - Controlling circuit for liquid fuel combustor - Google Patents

Abstract

PURPOSE:To prevent malodor from being generated due to defective ignition or incomplete combustion, by igniting a mixed gas of a gaseous fuel and combustion air when an air-supplying motor has reached a predetermined rotating speed. CONSTITUTION:With a power switch 16 closed, power is supplied to a combustion- controlling circuit 17, upon which an evaporating heater 7 and an air-supplying motor 1 are energized, the motor 1 is rotated, and a comparator outputs rectangular pulses. As the rotating speed of the motor is increased, the period of the rectangular waveform of the pulses becomes shorter. When the motor 1 has reached a predetermined rotating speed, the comparator outputs a high-level voltage to the circuit 17 as an igniting signal. The circuit 17 outputs an ignition control signal and a fuel-supplying signal respectively to an ignition-controlling circuit 22 and a fuel-supplying circuit 21, and an electromagnetic pump 12 supplies a liquid fuel to a burner part. The liquid fuel is evaporated by the heater 7, and a gaseous mixture of the evaporated fuel and combustion air is jetted from a burner port 11, and is ignited by an ignition plug 14, to be burned. Thus, the mixed gas is ignited when the rotating speed of the air- supplying motor has reached the predetermined speed, whereby defective ignition or generation of malodor is prevented from occurring.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to a control circuit for a liquid fuel combustion device.

(b) Conventional technology Conventionally, the control circuit for this type of liquid fuel combustion device was
As disclosed in Publication No. 133520, etc., when the burner body is heated with a vaporization heater and a burner thermistor etc. detects that the burner body has reached a predetermined temperature, the air supply fan driven by the air supply motor is rotated. After pre-purging, that is, after a certain period of time has passed since the air supply motor rotates, the electromagnetic pump is operated to supply liquid fuel to the burner body, where it is vaporized by the vaporization heater and mixed with the combustion air supplied by the fan. The fuel was then ignited using a spark plug to cause combustion.

(c) Problems to be Solved by the Invention However, this conventional liquid fuel combustion device has the disadvantage that the starting characteristics of the air supply motor deteriorate as the temperature decreases, and the time required for the rotation speed to stabilize is longer. Because
If the pre-purge time is fixed using, for example, a microcombination or timer circuit, the amount of vaporized fuel and the amount of combustion air will be balanced at room temperature, resulting in good ignition.
At low temperatures, the amount of combustion air is small compared to the amount of vaporized fuel, which means that the rotational speed of the air supply motor is slow, so ignition may not occur, or even if ignition does occur, incomplete combustion causes a bad odor.

The present invention has been made in view of the problems of the prior art described above, and its technical problem is to prevent ignition failure and bad odor by igniting when the rotational speed of the air supply motor reaches a predetermined speed.

B) Means for Solving the Problems The present invention solves the above problems, and the same content will be explained below using FIGS. 1, 2, and 3 corresponding to the embodiments. do.

The liquid fuel supplied to the burner body (5) by the electromagnetic bonder QZ is vaporized by the vaporization heater (7), and the air supply motor (
1) In a liquid fuel combustion device that mixes combustion air supplied by an air supply fan (4) driven by an air supply fan (4) and ignites and burns it with a spark plug I, the rotational speed of the air supply motor (1) is detected. A motor rotation speed detection circuit (4) that outputs a high-level voltage as an ignition signal when a preset rotation speed is reached, and the motor rotation speed detection circuit (3).
The combustion control circuit αη operates the electromagnetic pump and the spark plug side based on a high level voltage from the combustion control circuit αη.

(E) Operation The motor rotational speed detection circuit detects the rotational speed of the air supply motor (1) and outputs a high level voltage as an ignition signal to the combustion control circuit αη when the rotational speed reaches a predetermined rotational speed. Then, the combustion control circuit αη transmits the ignition control signal to the ignition control circuit
Then, a fuel supply signal is output to the fuel supply circuit (Inc.), and the spark plug I and electromagnetic pump α2 are operated to ignite and burn the mixture of vaporized fuel and combustion air.

(f) Example An embodiment of the present invention will be described in detail below based on the drawings.

Figure 3 is a diagram showing the burner section of the liquid fuel combustion device.
) is an air supply motor, which is equipped with a rotary atomizer (3) for atomizing liquid fuel at one end of a rotating shaft (2) and an air supply fan (4) for supplying combustion air at the other end. There is.

(5) is a burner body which is provided with a vaporization chamber (6) inside which vaporizes the fuel atomized by the rotary atomizer (3), and the burner body (5) is made of iron casting, aluminum die-casting, etc. is forming. (7) is a vaporization heater for raising and maintaining the vaporization temperature of the fuel in the vaporization chamber (6);
), and (9) is a burner head with a large number of flame openings αυ for forming combustion flame α1.
9) A combustion chamber is formed above. α2 is an electromagnetic bonder that supplies fuel to the rotary atomizer (3), αJ is a burner thermistor that detects the temperature of the burner body (5), α
1) The spark plug C151 facing the flame opening αυ is a flame rod that faces the flame opening συ together with the spark plug αυ and serves as a sensor of a flame detection device.

FIG. 2 is a system block diagram of the control circuit, which will be described in detail below with reference to the drawings. (161 is a power switch which, when closed, supplies V□ power to the combustion control circuit a. The combustion control circuit αη is composed of a microcombination circuit, etc., and is used for burner temperature detection circuit and heater control. The burner thermistor α, the evaporation heater (power), and the air supply motor (1 ), an electromagnetic pump α2, and a spark plug α4.The combustion control circuit α power is connected to the heater control circuit (19), which is a heater control signal when the power switch is closed.
The air supply motor control signal is outputted to the air supply motor control circuit (2) to drive the vaporization heater (7) and the air supply regulator (1). Furthermore, when the combustion control circuit (17) receives the high level voltage from the motor rotational speed detection circuit (a), it outputs a fuel supply signal to the fuel supply circuit (2I) and an ignition control signal to the ignition control circuit C3. and drives the electromagnetic pump α2 and spark plug α4.

Next, the motor rotation speed detection circuit (4) will be explained in detail based on FIG. Q With the Hall element, the air supply motor (
1) is close to the permanent magnet attached to the rotating shaft (2) so that the magnetic field of the permanent magnet can penetrate thereto. A current is passed through the Hall element @ from the front to the back of the figure, and the terminal A (24a) and the non-inverting input terminal of the comparator (to) are connected to the terminal B (24b) and the inverting input terminal of the comparator (c). The input terminals are connected to each other. The output terminal of the comparator (c) is connected to the capacitor and the grounded resistor.
It is connected to the capacitor of a differentiating circuit consisting of. @ is a diode whose anode side is grounded, and is connected to the capacitor (G) and the resistor (5) at a connection point (Pl). (C) is a buffer that amplifies the waveform, and its input terminal is connected to a connection point (PI), and its output terminal is connected to a resistor (to). The resistor (to) and the smoothing capacitor 3υ are connected at a connection point (Pl), and a resistor 64 connected to the Voo power source and a grounded resistor Q are connected at a connection point (P3). (B) is a comparator that compares the voltage between the inverting input terminal and the non-inverting input terminal, and the non-inverting input terminal is the connection point (Pl), and the inverting input terminal is the connection point (P3).
) are connected to each other. The output terminal of the comparator (to) is connected to the combustion control circuit aη.

The present invention has the above-mentioned configuration, and its operation will be described in detail below.

When the power switch σG is closed, v1 is applied to the combustion control circuit ση.
A 1DIft source is provided. Then, the combustion control circuit α
A signal is output from η to the heater control circuit σ9 and the air supply motor control circuit (2), and the vaporization heater (7) and the air supply motor (1) are energized, respectively. The air supply motor (1) rotates;
When the magnetic field of the permanent magnet attached to the rotating shaft (2) enters the Hall element (24), terminal A B (24a) (24
b) Generates a potential difference between. Therefore, the comparator outputs a pulse with a square waveform. The rectangular pulse is differentiated by the capacitor and the resistor (5), but because of the diode, only the positive component is present. Then, this waveform is amplified by a buffer wire and smoothed by a smoothing capacitor FC31) to become a DC voltage.

As the rotational speed of the air supply motor (1) increases, the period of the square wave output from the comparator (c) becomes shorter.

Then, the period of both the waveform output to the connection point (PI) and the waveform amplified by the buffer (c) becomes shorter, and the average voltage per period becomes higher. Therefore, the DC voltage input to the non-inverting input terminal of the comparator (b) becomes higher than when the rotational speed of the air supply motor (1) is slow.

The input potential of the non-inverting input terminal of the controller (b) becomes higher than the potential of the inverting input terminal of the air supply motor (1
) reaches a predetermined rotational speed, the comparator (b) outputs a high-level voltage as an ignition signal to the combustion control circuit aη.

Combustion control circuit U transmits high level voltage from comparator (B)
When the output is output to , the combustion control circuit αη becomes the ignition control circuit @
and a fuel supply circuit (2υ), the electromagnetic bonder α2 supplies liquid fuel to the burner section, the liquid fuel is vaporized by the vaporization heater (7), and the vaporized fuel and combustion air are The mixture is ejected from the flame port αυ, and the spark plug I ignites and burns it.

(g) Effects of the Invention The present invention is as described above, and the mixture of vaporized liquid fuel and combustion air is ignited when the air supply motor reaches a predetermined rotational speed, regardless of changes in starting characteristics due to room temperature. So,
An appropriate amount of combustion air can be obtained, preventing bad odors caused by ignition failure and incomplete combustion, and more reliable ignition can be expected.

Furthermore, since the motor speed detection circuit detects that the predetermined rotational speed has been reached, prepurge can be reliably performed in the shortest possible time regardless of the room temperature.

[Brief explanation of the drawing]

FIG. 1 is a motor rotation speed detection circuit diagram, FIG. 2 is a system block diagram of a control circuit, and FIG. 3 is a diagram showing a burner section of a liquid fuel combustion device. Prisoner...Motor rotational speed detection circuit, (lη...Combustion control circuit, @...Permanent magnet, 241...Hall element, (support) (B)...Comparator.

Claims (1)

[Claims] (1) Liquid fuel combustion in which liquid fuel supplied to the burner body by an electromagnetic pump is vaporized by a vaporization heater, mixed with combustion air supplied by an air supply fan driven by an air supply motor, and then ignited and combusted by an ignition device. The device includes a motor rotation speed detection circuit that detects the rotation speed of the air supply motor and outputs an ignition signal when the rotation speed reaches a preset rotation speed, and an ignition signal based on the ignition signal from the motor rotation speed detection circuit. A control circuit for a liquid fuel combustion device, comprising a combustion control circuit that operates the electromagnetic pump and the ignition device.