JPH0585812B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vaporizing liquid fuel combustor having a control device capable of stabilizing and improving combustion performance.

(Prior technology) In vaporizing liquid fuel combustion machines (hereinafter referred to as vaporizing combustion machines) such as vaporizing oil stoves used in general households during the winter, a flame detector is attached to the gasifying burner to prevent combustion. Many of them constantly detect the state of the flame during operation and adjust the supply amount of liquid fuel and combustion air to maintain high combustion efficiency and complete combustion. As disclosed in Japanese Patent Application Laid-Open No. 59-125327, its contents are well known.

The vaporization combustion machine in the above publication uses an AC voltage as a flame detector between the gasification burner head and the flame rod, detects the DC flame current flowing due to the rectification phenomenon of the combustion flame, and detects the detected current. If it is too large, it indicates yellow combustion (yellow combustion state due to insufficient air supply) and outputs a signal to increase the amount of air supply, and if it is too small, it indicates lift combustion due to too much air and outputs a signal to reduce the amount of air. I'm using whatever structure I can get. (See Figure 8) (Problems to be solved by the invention) As mentioned above, the combustion state is detected by a flame detector,
It can be said that a vaporization combustion machine configured to increase or decrease the amount of air supply is reasonable in terms of controlling the flame current to be within a certain range, but in this case,
This is based on the premise that the flame current tends to be larger during yellow combustion than during stable combustion, and the inventors conducted various experiments under the same conditions as actual usage, and found that the Even if the amount of gas decreases, if this amount decreases greatly, as is clear from the experimental results shown in Figure 7, if the flame current becomes as small as _I1 , the current will decrease even in yellow combustion. The value has decreased, making it impossible to determine whether it is yellow combustion or lift combustion.

Yellow combustion under such conditions can be controlled to stable combustion by increasing the amount of air supply, but with conventional combustion, it is difficult to determine whether it is yellow combustion or lift combustion, so The gasification burner is activated as a safety device to stop the gasification burner when the current drops below a certain value, and when the specific gravity of the air decreases as the room temperature rises, the flame current decreases, forcing the combustion operation to stop. Therefore, the operable range is narrow and restarting after automatic stop is troublesome, resulting in various practical inconveniences.

From this point of view, the present invention can solve the conventional drawbacks by discovering that the states of lift combustion and yellow combustion are affected by the amount of air supplied, that is, the difference in specific gravity of the air. It is an object of the present invention to discover a new configuration, and to expand the operating range and achieve accurate combustion control that is suited to combustion conditions.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a gasification burner 1, and a method for supplying combustion air and liquid fuel to the gasification burner 1 in a synchronous manner. A voltage is applied between the burner motor 2, the burner head 3 of the gasification burner 1, and the flame rod 4, and the flame current flowing at that time is detected. If the detected current is larger than the set current, a normal combustion signal is generated. a flame detector 5 that outputs an abnormal combustion signal if the temperature is small, and a flame detector 5 that detects the temperature of the combustion air and outputs a high temperature signal if the detected temperature is higher than the set temperature, and a low temperature signal if it is lower. When the detector 6 and the flame detector 5 are outputting an abnormal combustion signal and the temperature detector 6 is outputting a low temperature signal, an increase signal is output, while when it is outputting a high temperature signal. The evaporative combustion machine is equipped with a command circuit 7 for outputting a reduction signal, and an output circuit 8 for decreasing the rotation speed of the burner motor 2 in accordance with the reduction signal from the command circuit 7 and increasing the rotation speed in response to an increase signal. It is characterized by being closed.

(Function) The function of the present invention having the above-mentioned characteristics is as follows. In the gasification burner, when the rotation speed of the burner motor is constant, the air volume and oil volume are constant, but the volume density changes depending on the temperature of the air volume. Since the change is large compared to that of the oil amount, the combustion state generally changes depending on the change in room temperature, as shown in Figure 5 A, B, C and Figure 6, and when the room temperature is low, lift combustion, It is known that when the temperature is high, there is a tendency for yellow combustion.

On the other hand, it is also known that the flame current value tends to decrease when shifting to lift combustion or yellow combustion, and this point is also clear from the above explanation based on FIG. 7.

By the way, the gasification burner 1, which supplies combustion air and liquid fuel to the gasification burner 1 in a synchronously adjustable manner, has a lift combustion tendency when the rotation speed of the burner motor 2 is low (weak combustion), and a high-speed combustion tendency. (Strong combustion) tends to cause yellow combustion, so if the flame current is small and the room temperature is low, this is determined to be lift combustion and the rotation speed of the burner motor 2 is increased; If it is determined that combustion is occurring and the rotation speed of the burner motor 2 is reduced, negative feedback will be applied to the combustion state during normal combustion, improving combustion performance, while positive feedback will be applied during abnormal combustion. Since return is required, abnormalities can be detected faster.

In other words, from the stable combustion state (the set condition state), the flame current and air temperature change state is changed to the fourth state.
As shown in the figure, control is performed to read and finely adjust the rotation of the burner motor 2.

In this way, it is possible to suppress the activation of the safety device as much as possible and to perform stable combustion operation under a wide combustion capacity range.

(Example) Hereinafter, one example of the present invention will be described based on the accompanying drawings.

FIG. 2 is a schematic structural diagram of a gasification burner 1 of a vaporization combustion machine according to an example of the present invention, which has a combustion part, a vaporization part, a fan part, and a pump part successively connected from the top to the bottom. .

The combustion section includes a burner head 3 having a large number of flame ports 19, a flame rod 4 and a spark plug 2 provided in a position in contact with the flame formed in the burner head 3.
has 0.

The vaporization section includes a vaporizer 15, a vaporization heater 17, and a diffusion vane 18.

The fan section includes a blower fan 14 for sending combustion air introduced from an air intake port with a damper 21 interposed therebetween to the vaporizing section, and the blower fan 14 is axially connected to one shaft of the burner motor 2.

The pump part has an oil pump 11 in the lower part, which is formed by an outer cylinder having a fuel filler port 22 and a drain plug 23 for feeding liquid fuel such as kerosene, and a nozzle 12 opening downward, and has a pump chamber 13 in the upper part. The shaft of the oil pump 11 is connected to the other shaft of the burner motor 2.

The gasification burner 1 having such a structure is called a synchro gasification burner which has an oil pump 11 and a blower fan 14 coaxially integrated, and first, in the combustion system, fuel is passed from an oil tank etc. through an oil level regulator etc. to a pump chamber. 13, and the oil level is maintained at a constant level.

Fuel pressurized by the oil pump 11 due to the rotation of the burner motor 2 is made into a constant oil amount by the nozzle 12, passes through an oil passage provided in the shaft of the burner motor 2, reaches the diffusion vane 18, and is radiated and scattered there by centrifugal action. .

The scattered oil particles collide with the wall of the vaporizer 15, which is heated by the vaporization heater 17 (to 260 to 290° C.), and are vaporized.

On the other hand, in the combustion air system, as the blower fan 14 rotates, air flows from the damper 21, is pressurized, and flows into the carburetor 15.

In this case, about 70% is primary air and about 30% is secondary air.
Supplied as air.

The primary air introduced into the vaporizer 15 is emitted from the slit of the flame port 19 while being mixed with the fuel that has been atomized and vaporized by the diffusion vanes 18, and is ignited by the spark plug 20 to continue combustion.

There is a flame rod 4 in this combustion flame that is electrically insulated from the burner body, so when an AC voltage is applied between it and the burner head 3, the combustion flame rectifies, causing the flame rod 4 to move toward the burner head 3. A direct current flame current flows, and the flame rod 4 forms the detection end of the flame detector 5, as described above.

Next, the combustion control system will be explained based on FIGS. 1 and 3. It consists of a flame detector 5 that detects the flame current, a temperature detector 6 that detects room temperature as a resistance change using a thermistor, and a logic circuit. A combustion control system is formed by the command circuit 7 and the output circuit 8 which outputs an output to the burner motor 2 to decrease or increase the rotation speed.

The flame detector 5 includes a flame current detection circuit 5A, and an A/D converter that converts the current detected by the detection circuit 5A into voltage.
It consists of a V conversion circuit 5B, a voltage generation circuit 5C that generates a reference voltage corresponding to a reference setting current, and a comparison circuit 5D that compares this reference voltage with the output voltage of the A/V conversion circuit 5B. If the flame current is larger than the set current, a normal combustion signal (for example, L output) is output, and if it is smaller than the set current, an abnormal combustion signal (also H output) is output.

On the other hand, the temperature detector 6 is a temperature detection circuit 6A including a thermistor that detects room temperature as a resistance change.
An R/V conversion circuit 6B that converts the resistance change of the temperature detection circuit 6A into a voltage, a voltage generation circuit 6C that generates a reference voltage corresponding to the reference temperature, and an output voltage between this reference voltage and the R/V conversion circuit 6B. It operates to output a high temperature signal (eg, L output) if the detected room temperature is higher than the set temperature, and to output a low temperature signal (also H output) if it is lower than the set temperature.

Next, the command circuit 7 is formed by a combination of an exclusive OR circuit 7A and two AND circuits 7B and 7C, and the flame detector 5 outputs an abnormal combustion signal "H", and the temperature detector 6 is outputting the low temperature signal "H", AND circuit 7B
outputs an "L" output, and the AND circuit 7C outputs an "H" output, resulting in a state in which an increase signal "+ΔN" is output.

Further, when the flame detector 5 is outputting the abnormal combustion signal "H" and the temperature detector 6 is outputting the high temperature signal "L", the AND circuit 7B outputs "H",
The AND circuit 7C issues an "L" output, and a state is reached in which a reduction signal "-ΔN" is output.

On the other hand, when the flame detector 5 is outputting the normal combustion signal "L" and the temperature detector 6 is outputting the low temperature signal "H", the AND circuit 7B outputs "L",
The AND circuits 7C each issue an "L" output, resulting in a state in which an appropriate amount signal, that is, a status quo maintenance signal is output.

Furthermore, when the flame detector 5 is outputting the normal combustion signal "L" and the temperature detector 6 is outputting the high temperature signal "L", the AND circuit 7B outputs "L" and the AND circuit 7C outputs "L". Emit "L" output respectively,
The state is such that an appropriate amount of signal is output.

Next, the output circuit 8 is formed of relays X ₁ and X ₂ each having a switching contact, a transistor Q ₁ connected in series to the coil of relay X ₁ , and a power transistor Q ₂ connected in series to the coil of relay X ₂ . When the command circuit 7C outputs the increase signal "+ΔN", the relay _X2 is activated to connect the "H" tap to the power supply, and the command circuit 7C outputs the decrease signal "-
When outputting ΔN, _relay ” tap is for reducing the rotation speed.

The burner motor 2 is a 3-speed single-phase AC motor, and the "M" tap normally rotates N rotations.
Three rotations are performed: increasing rotation (N+ΔN) by tapping " _H " and decreasing rotation (N-ΔN) by tapping "L _" . Connect to commercial power supply using the wiring instructions shown in the diagram.

In FIG. 3, 9 is a rectifier circuit, 10 is a separately provided relay for starting and stopping the burner motor, and Tr is a transformer for obtaining two types of low voltage.

In the combustion control system having such a structure, when the room temperature detected by the temperature detector 6, that is, the temperature of the combustion air, is higher than the set temperature, for example, 10°C, the output of the comparator circuit 6D becomes "L"; The output becomes "H".

On the other hand, in the flame detector 5, when the flame current is larger than the set current, for example 10 μA, the output of the comparator circuit 5D is "L", and when it is smaller, the output is "H".

Therefore, when the comparator circuit 6D outputs "H" and the comparator circuit _5D outputs "H", the relay Relay when 6D outputs “L” and comparison circuit 5D outputs “H”
X ₂ is energized and the burner motor 2 receives an output to decrease the rotational speed, thereby decreasing the rotation by ΔN.

In states other than the two mentioned above, relays X ₁ and X ₂ are deenergized to maintain the current N rotation.

In this way, the flame detector 5 is outputting an abnormal combustion signal (the flame current is small),
If the temperature detector 6 outputs a low temperature signal, it is determined that lift combustion is occurring, and the amount of fuel and air in the gasification burner 1 is increased.On the other hand, if the temperature sensor 6 outputs a high temperature signal, yellow combustion occurs. If it is determined that the amount of fuel is present, the amount of fuel and the amount of air are reduced, and in either case, control is performed in a direction that balances the supply amount of fuel and air, and stable combustion can be achieved.

(Effects of the Invention) The present invention has the configuration and operation as described above, and determines whether there is an abnormality in the combustion state based on the relationship with the temperature of the combustion air to be supplied, in other words, based on the specific gravity of the air. Since it is possible to accurately distinguish between lift combustion and yellow combustion, it is possible to perform stable and high-performance combustion control over a wide range of capacities, eliminating the inconvenience of repeatedly activating the safety device. , can always maintain optimal combustion conditions.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a combustion control system according to an example of the present invention, FIG. 2 is a schematic structural diagram of a gasification burner, and FIG. 3 is a developed diagram of a combustion control system according to an embodiment of the present invention. Figures 4 to 6 are characteristic diagrams explaining the principle of combustion control of the present invention, Figure 7 is a characteristic diagram obtained by actual measurement of the relationship between the air flow rate of the gasification burner and the flame current, and Figure 8 is FIG. 2 is a characteristic diagram for explaining the performance of a conventional vaporization combustion machine. 1... Gasification burner, 2... Burner motor, 3
... Burnahed, 4... Flamerod, 5...
...Flame detector, 6...Temperature detector, 7...Command circuit, 8...Output circuit.

Claims (1)

[Claims] 1 gasification burner 1, and the gasification burner 1 capable of synchronously adjusting increase/decrease of combustion air and liquid fuel.
A voltage is applied between the burner motor 2 that supplies the gas to the burner head 3 and the flame rod 4 of the gasification burner 1, and the flame current flowing at that time is detected. If the detected current is larger than the set current, it is normal. a flame detector 5 which outputs an abnormal combustion signal if the combustion signal is small, and a flame detector 5 which detects the temperature of the combustion air and outputs a high temperature signal if the detected temperature is higher than the set temperature and a low temperature signal if it is lower. When the output temperature detector 6 and the flame detector 5 are outputting an abnormal combustion signal, and the temperature detector 6 is outputting a low temperature signal, an increase signal is output, and a high temperature signal is output. A command circuit 7 outputs a weight loss signal when
and an output circuit 8 for decreasing the rotation speed of the burner motor 2 in response to a reduction signal from the command circuit 7 and increasing the rotation speed in response to an increase signal from the command circuit 7. .