JPS6166007A - Combustion device for liquid fuel - Google Patents

Abstract

PURPOSE:To contrive to make the amount of the combustion and air-fuel ratio constant by a method wherein an evaporator, accommodating a sucking body and an heating body and communicating with a fan and a combustion unit, fuel liquid temperature and air temperature in the evaporator, and the control unit of the amount of conducted electric current of the heating body are provided in the title device. CONSTITUTION:Almost all of the amount of heat generated by the conduction of a heating body 5 becomes sensible heat and latent heat evaporating the oil of a sucking body 6 and contributes to evaporate the oil. In this case, the oil temperature may move up and down by the fluctuation of atmospheric temperature, the effect of heat of combustion, oil supplying operation or the like. The detecting unit 9 of oil temperature is provided in order to correct above factor and the amount of conducted electric current of the heating body 5 is reduced in accordance with the increase of the oil temperature to make the amount of combustion constant. The detecting unit 10 of atmospheric temperature is provided on the way of an air path and the air-fuel ratio is controlled so as to make it constant by changing the amount of conducted electric current in accordance with the fluctuation of the atmospheric temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a liquid fuel combustion device that is applied to fields that use liquid fuel, such as space heating, hot water supply, industrial heating equipment, and power combustion equipment.

Conventional Structures and Problems There have been various proposals for devices for vaporizing liquid fuel using absorbents. However, because it uses a wicker, which is a fuel supply means that relies on capillary action, a stable amount of combustion cannot be expected.

In order to eliminate these drawbacks, a method was proposed in which the suction body was heated using an electric heating element, but even with this method, it was not possible to obtain a constant combustion amount because the oil was susceptible to fluctuations in oil temperature. It was something.

In addition, the capacity of the blower used in combustion equipment is also easily affected by the temperature, and as the temperature rises, the amount of air blown decreases, and as the temperature rises, the oil temperature rises and the amount of combustion increases. The air-fuel ratio varied widely, causing problems such as incomplete combustion and flashback.

Purpose of the Invention The present invention uses a simple mechanism using a suction body to suck up liquid.
The purpose is to keep the combustion amount constant and the air-fuel ratio constant in those that use a heating element to turn vaporized gas.

Structure of the Invention In order to achieve the above object, the liquid fuel combustion device of the present invention includes a wicking body that sucks up liquid fuel by a rod-and-pipe action, a heating element that vaporizes the liquid in the upper part of the wicking body, and the wicking body and the heating element. A vaporizer having a built-in device and communicating with a blower and a combustion section, a fuel supply section to the vaporizer, a liquid temperature and air temperature detection section of the vaporizer, and an energization amount control section for the heating element are provided. In response to the increase in temperature, the amount of current applied is reduced to increase the amount of combustion, and
As the temperature increases, the amount of current is further reduced to stabilize the air-fuel ratio.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 1
is a vaporizer whose bottom part communicates with a constant liquid level device 3 through a pipe 2, and the oil in the oil tank 4 flows through the constant liquid level device 3 and the pipe 2 to the vaporizer 1 to maintain a constant liquid level. Reference numeral 6 denotes a suction body made of porous material, fiber, etc., whose lower part is placed in the liquid of the vaporizer 1 and whose upper part is in contact with the heating element 5, and which covers and contacts the heating element 5 and generates heat. The heat of the body 6 efficiently vaporizes the liquid in the wick 6. Also, one end of the vaporizer 1 is a flat saw.

It communicates with a centrifugal blower such as a turbo, and introduces air for conveying vaporized gas, which becomes an air-fuel mixture from the other end and is combusted in the combustion section 8.

In the above configuration, when the heating element 5 is energized, almost all of the generated heat becomes sensible heat and latent heat that vaporize the oil in the wicking element 6, which contributes to the vaporization of the oil.
This is because the absorbent body 6 covers the surrounding area, so that almost no heat flows anywhere else.

Therefore, in principle, a constant amount of vaporization can be obtained with a constant amount of current applied. However, if the oil temperature rises due to changes in outside temperature, the influence of combustion heat, oil supply equipment, etc., the amount of vaporized gas will increase due to the decrease in the amount of sensible heat required to vaporize the oil.

Needless to say, the opposite is true when the oil temperature decreases. Such fluctuations in the amount of vaporized gas cause fluctuations in the combustion amount and an imbalance in the air-fuel ratio, resulting in incomplete combustion. For example, in the data using kerosene as an example, when the oil temperature is +2 o'C, the amount of vaporization increases by about 20% when the oil temperature becomes +eo'c. In order to correct this, in this embodiment, an oil temperature detection section 9 is provided. , the amount of electricity supplied to the heating element 6 is reduced in accordance with the increase in oil temperature, thereby stabilizing the amount of combustion.The detection unit 9 may be provided at any position that has a correlation with the liquid temperature. These include the outer wall of the submerged vaporizer 1, the vicinity of the heating element 5, etc.

On the other hand, a commonly used centrifugal blower has a characteristic that its blowing capacity fluctuates widely depending on changes in temperature, and even if the amount of combustion is simply constant, it is not sufficient. The analogy is +
Compared to an air temperature of 20"C, the amount of air blown at +60°C is reduced by about 12%.

Therefore, in order to keep the air-fuel ratio constant, it is necessary to reduce the amount of current applied in order to reduce the combustion amount by about 12%.

For this purpose, in this embodiment, a temperature detection section 10 is provided in the air path. Oil temperature and air temperature are both +20°.
When the temperature rises from C to +eo'c, if a constant amount of current is continued to flow without any control, the amount of air will be 88% and the amount of vaporization will be 1.
20%, the air-fuel ratio becomes a value of 73% (0.88/1.2), and combustion becomes completely unstable.

As described above, in this embodiment, the amount of energization is changed to keep the combustion amount constant in response to fluctuations in oil temperature, and the amount of energization is further changed to keep the air-fuel ratio constant in response to fluctuations in temperature. It is something. The means for controlling the amount of current is, for example, an alternating current wave number control system, in which the signals obtained by detecting the oil temperature and air temperature are processed and calculated by the microcomputer 12, and a wave number signal that meets the conditions is sent to the bidirectional thyristor 11. All you have to do is output it. Also, since oil temperature and air temperature usually have a correlation in indoor equipment, it is okay to detect one of them, but if there is no correlation, such as when the oil temperature is affected by combustion heat, it is not necessary to separately detect both. Must not be. Of course, the temperature should be detected at a position that has a correlation with the operating air of the blower 7, and as long as this is possible, it can also be used in common with the temperature detection section for a room thermostat.

Furthermore, as described above, when there are no oil islands, two types of detection units are required. However, there is no vaporizer 1 in the air path 13 of the blower 7.
If the air temperature and the liquid temperature are exchanged with each other, the temperatures of the two will be approximately the same. Therefore, only one detecting section 9 is required as shown in FIG. 2. In this case, the detection section may be provided on either the oil side or the air side.

Next, an optimal method for controlling the amount of electricity supplied to the heating element 5 with respect to the detected oil temperature and air temperature will be described.

First, the oil temperature t of the vaporization amount G (KP'/h). The variation for 'C is as follows.

G=−1−−−−−−−−−−−−−C(t b
t e ) ” Q W : Amount of electricity applied to the heating element Kc/h C: Specific heat KCaJ/,/°Ctb: Boiling point of the liquid °C Q: Latent heat of the liquid KcaA/Shimata, H=Ct b+ Q.

H: enthalpy of vaporized gas at the boiling point KcaJl/drive where H is a constant determined by the type of liquid; for example, in the case of kerosene, it is approximately 150 Kcall/fCyT:.

Therefore, G=W/(H−Ct,).

In addition, the air volume changes in proportion to the specific weight of the operating gas, so the air volume is as follows: TO: Reference temperature K Ao: Air volume at To m/h T: Air temperature during operation K A: Operating temperature The air volume per hour is 1/h. Therefore, the air-fuel ratio m is as follows.

Here, α is a constant, so air temperature Ta and oil temperature T.

If the energization amount W is controlled so that (H-Ct)/TaW remains constant with respect to the change in the air-fuel ratio, the air-fuel ratio becomes constant. For example, in the case of kerosene, the above formula is (150-0,5
4t, ) / Ta W = const.

In this embodiment, since H can be regarded as a constant as described above, such control is possible.

FIG. 3 shows another embodiment of the present invention, in which combustion heat is fed to the oil of the carburetor 1 through the heat transfer path 14, thereby increasing the oil temperature and reducing power consumption. This feedback heat differs between ignition and combustion and tends to cause the combustion amount to become unstable, but if the liquid temperature is detected by the control device described above, the combustion amount will not become unstable.

Effects of the Invention As is clear from the above explanation, according to the present invention, the amount of vaporization can be arbitrarily controlled with a simple configuration, preventing imbalance in the air-fuel ratio due to fluctuations in oil temperature and air temperature, and accurately controlling the air-fuel ratio. Therefore, water heaters and space heaters using the present invention can achieve effects such as clean combustion, high efficiency combustion, and wide range of combustion volume.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a liquid fuel combustion device showing one embodiment of the present invention, Fig. 2 is a cross-sectional view of another embodiment of the present invention, and Fig. 3 is a cross-sectional view of yet another embodiment of the present invention. It is. 1... vaporizer, 6... heating element, 6...
...Suction body, 7...Blower, 9...Detection section, 10...Detection section. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3

Claims (3)

[Claims] (1) A wicker that sucks up liquid fuel by capillary action, a heating element for vaporization located above the wicker and surrounded by the wicker, and a blower and a vaporizer communicating with a combustion section, a fuel supply section to the vaporizer, a detection section for liquid temperature and air temperature of the vaporizer, and reducing the amount of electricity supplied to the heating element in response to an increase in the liquid temperature; A liquid fuel combustion device equipped with an energization amount control unit that controls the amount of energization of a heating element to be reduced in response to an increase in temperature. (2) The liquid fuel combustion device according to claim 1, wherein a heat exchange section between the combustion air by the blower and the liquid in the vaporizer is provided, and the liquid temperature and the air temperature are detected by the same detection section. . (3) Enthalpy H that the vaporized gas has at its boiling point, specific heat C of the liquid fuel, detected liquid temperature t_e, absolute temperature Ta of the detected air temperature, expressed as the amount of current W (H-CTe)/Ta
2. The liquid fuel combustion device according to claim 1, wherein the energization amount control section controls the energization amount W so that the value of W is substantially constant.