JPS6332218A - Burning control device - Google Patents

Abstract

PURPOSE:To enable maintaining a satisfactory burning condition under keeping an air-fuel ratio in constant by a method wherein the air supply quantity is increased and decreased to be adjusted to a previously set value in response to the outputs from the primary and secondary temp. detectors. CONSTITUTION:Air supplied from a blower 4 is heated in a carburetor 5 and then sent to a burning part 1 and this temp. is temp. 1. The detection of the temp. at the primary temp. detector 10 (afterwards this temp. is named as temp. 2) makes it possible to know the temp. rise of air from the difference (temp. 1-temp. 2). At an operational comparator 13 each value of (temp. 1-temp. 2) when the burning quantity and an air-fuel ratio mu are previously changed is stored. The burning quantity from a burning quantity output part 12 and the temp. difference from the primary and secondary temp. detectors 11, 9 are fed, and when the air ratio differs from a set value mu, the ratio is adjusted by the increase and decrease in the revolving speed of the blower 4 caused by an air control part 14. On this account, the air-fuel ratio can freely be set at the most suitable value and therefore, the ratio can be set even in the whole primary region such as mu=1.5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an air-fuel ratio control device for combustion equipment that uses fuel such as gas or oil.

2. Conventional technology When burning gas or oil as fuel, by supplying the fuel and air at an optimal ratio, backfire, misfire, or incomplete combustion can be prevented and stable combustion can be achieved. Can be maintained. This ratio of the amount of fuel and air is called the air-fuel ratio, and conventional methods have been devised to detect the combustion state and control the amount of fuel or air so as to always maintain an optimal air-fuel ratio.

An air-fuel ratio control method for oil-burning equipment is described, for example, in Jikai %61-24917. This system detects the flame ion current of the flame with a flame rod inserted into the flame, and uses the fact that this ion current changes depending on the air-fuel ratio to adjust the driving frequency of the fuel supply pump to optimize the air-fuel ratio. It is. FIG. 3 shows an example of the flame ion current value If. The horizontal axis is the primary air ratio μ, and here the air-fuel ratio will be explained in terms of the primary air ratio μ.

Typical burner input range (3,000 to 1,000
kcal/h), the flame ion current value I (is approximately μ
It has a distribution with a peak at 0.8 to 0.9.

3.\-7 Therefore, by adjusting the pump driving frequency and determining the amount of fuel supplied so that the flame ion current value becomes the maximum value, the air-fuel ratio is controlled and a stable combustion state is maintained.

Problems to be Solved by the Invention In the conventional example described above, a burner configured to maintain the most stable combustion state at μm of 0.8 to 0.9 was used.
A burner configured to maintain the most stable combustion state near μm1.5 (hereinafter referred to as a full-primary combustion burner)
There is also. Full combustion burners generally have low flame temperatures;
It is known that the burner configuration has a feature of extremely low levels of nitrogen oxides (NOx), which are harmful components in exhaust gas, and is highly effective for clean combustion.

However, the conventional air-fuel ratio control means as described above determines the fuel supply amount so that the flame ion current value If becomes the maximum value, so it is adjusted to 0.8 to 0.9 μm.
If a stable combustion state around 1.5 cannot be maintained and the input to the burner is small and the combustion amount is small, lf
The problem was that the value was small and the amount of change was even smaller, making detection difficult.

The present invention aims to solve such conventional problems, and aims to maintain a stable combustion state by controlling the micrometer to around 1.5 in a full-primary combustion burner.

Means for Solving the Problems In order to solve the above problems, the combustion control device of the present invention includes:
a vaporizer having means for supplying fuel and air, a heating means connected to the supply means, and a first vaporizer provided in the supply means;
a combustion section communicating with the vaporizer, and a second temperature detection means provided in a communication section between the vaporizer and the combustion section; The combustion control apparatus is configured to include combustion control that increases or decreases the supply amount of the air supply means to a preset value in accordance with the output.

Effect: With the above-described configuration, the present invention can measure the amount of air passing through the carburetor for combustion using the outputs of the first and second temperature detection means, so that the output 5.\-7 can be set to a preset value. By increasing or decreasing the supply amount of the air supply means, the air-fuel ratio can be arbitrarily set, and a stable combustion state can be maintained at the air-fuel ratio around 1.5 μm.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. In the embodiment, an indoor open combustion hot air heater (fan heater) using an oil vaporization burner will be described as an example. FIG. 1 shows a system block diagram of the present invention. Reference numeral 1 designates a full-primary combustion burner in which a flame port is formed with a wire mesh on the outside of a punched plate having a large number of small holes in the combustion section.
The air is supplied to the vaporizer 5. The vaporizer 5 is maintained at a high temperature by a heater 6, and the supplied fuel is vaporized, mixed with air, and supplied to the combustion section 1 as a mixed gas, where it is combusted. Reference numeral 7 denotes a second temperature detection means for detecting temperature, which is composed of a thermocouple or a thermistor, and a heat receiving fin 8 is provided on the outer periphery to measure the temperature of the fuel gas ejected from the carburetor 5, It is output to the temperature detection section 9. Reference numeral 10 denotes a first temperature detection means for detecting temperature, which is similarly composed of a thermocouple or a thermistor, measures the temperature of the air supplied from the blower 4, and outputs it to the first temperature detection section 11. fuel pump 3
The amount of fuel supplied is set according to the load, and an output corresponding to the supplied amount is output to the combustion amount input section 12. 1
Reference numeral 3 denotes an arithmetic comparison section which compares the comparison value with a previously stored value according to the values input from the second temperature detection section 9, the first temperature detection section 11, and the combustion amount input section 12, and controls the air amount. output to section 14. The air amount control section 14 is the calculation comparison section 13
The rotational speed of the blower 4 is controlled in accordance with the input from the air blower 4 to increase or decrease the amount of air.

FIG. 2 shows the characteristics of the temperature (hereinafter referred to as temperature 1) of the second temperature detection part in the full combustion burner, that is, the connecting part of the combustion part 1 of the carburetor 5. The temperature 1 decreases as μ increases and as the amount of combustion increases.

Air supplied from the blower 4 is heated in a vaporizer 5 whose temperature is controlled at a constant temperature, and then sent to the combustion section 1, which has a temperature of 1. The rise in air temperature within the vaporizer 5 is determined by the amount of air fed and the shape of the vaporizer. In the case of the same carburetor, the effects of fuel evaporation and temperature changes in the air are small, and are resolved only by the amount of air, the residence time and flow distribution of the air within the vaporizer, and the temperature drop on the surface of the vaporizer. Therefore, the larger the air ratio μ and the larger the combustion amount, the larger the amount of air supplied and the lower the temperature 1. By knowing the temperature in front of the vaporizer 5 supplied from the blower 4 by the first temperature detection unit 10 (hereinafter referred to as humidity 2), the upper temperature range of the air can be determined from (temperature 1 - temperature 2). The arithmetic comparison unit 13 is made to store in advance the values of (temperature 1 - temperature 2) when the combustion amount and the air ratio μ are changed. By inputting the combustion amount from the combustion amount input section 12 and the temperature difference from the first and second temperature detection sections 11.9, the air ratio μ can be determined by comparing with the above values. Then, it is compared with the set value μ, and if it is different from the set value μ, the air control unit 14 adjusts the rotation speed of the blower 4 by increasing or decreasing it.

Therefore, the air ratio can be freely set to the optimum value, so μ
It can also be set in all jurisdictions such as m1.6. Also,
The flame ion current is affected by the oxygen concentration in the room and the gas equivalent to tobacco, whereas the present invention, which measures the temperature rise of the supplied air, is affected by the above effects because the temperature rise is correlated with the mass flow rate of the air. Never. In this embodiment, the full-primary combustion burner has been described, but μ can be detected and controlled in the same way in the case of a partial premix combustion burner, and the temperature 2 may be substituted for room temperature or the like.

In the above configuration, the blower 4 is adjusted so that the value corresponding to the set air ratio μ and the combustion amount becomes the same as the value obtained by subtracting the second temperature detection means from the first temperature detection means, and the amount of air supplied is adjusted. acts to control the air ratio (for example, μm1)
．． 5) to maintain good combustion conditions. Although this example has been explained using an oil fan heater, the same effect can be achieved with combustion equipment other than fan heaters or gas combustion, and instead of using a vaporizer that maintains a constant temperature, the heater and the temperature of the heater can be detected. The same applies even if means are provided.

Effects of the Invention As described above, the combustion control device of the present invention provides the following effects.

(1) Since the air-fuel ratio can be automatically set to the optimal point, a stable combustion condition can be maintained at all times without the need for manual adjustment.

(2) Since the air-fuel ratio can be set according to the amount of combustion, it can be varied with good combustion, and the range of variable combustion amount can be expanded, making it possible to control the amount of combustion according to the load.

(3) Since it can be adjusted in μm 1.4 to 1.8, NOx
It can be applied to combustion control in full combustion burners with low combustion.

(4) Room temperature,
Accurate air ratio control is possible without being affected by combustion conditions.

(5) Since the supply air means is controlled according to the temperature difference of the supply air, the response is quick, and even if the air filter is partially clogged with dust or the like, even if the air ratio shifts, it can be adjusted instantly.

[Brief explanation of drawings]

FIG. 1 shows a control diagram of a combustion control device according to an embodiment of the present invention.
-7 Control block diagram, FIG. 2 is a characteristic diagram of the primary air ratio and the temperature of the first temperature detection section, and FIG. 3 is a characteristic diagram of a conventional air-fuel ratio control method. 1... Combustion part, 3... Fuel pump, 4
...Blower, 5... Carburizer, 7...
... second temperature detection means, 9 ... second temperature detection section, 10 ... first temperature detection means, 11.
...First temperature detection section, 12... Combustion amount input section, 13... Comparison calculation section, 14...
・Air amount control section.

Claims (2)

[Claims] (1) a vaporizer having a means for supplying fuel and air, a heating means connected to the supply means, a first temperature detection means provided in the supply means, and a combustion section communicating with the vaporizer; A second temperature detection means is provided at a connecting portion between the vaporizer and the combustion section, and the supply amount of the air supply means is increased or decreased according to the outputs of the first and second temperature detection means. Combustion control device. (2) The supply amount of the air supply means is increased or decreased according to the outputs of the temperature detection means of the vaporizer having the heating means and the first and second temperature detection means. Combustion control device.