JPH01174812A - Combustion equipment for liquid fuel - Google Patents

Abstract

PURPOSE:To dispose an auxiliary heater just above a combustion flame, and to improve the thermal response of passing liquid by forming the auxiliary heater for supplying a carburetor with previously heated liquid fuel by an inner tube made of a metal, a cushioning material and an outer tube made of ceramics. CONSTITUTION:A carburetor 2 is supplied with liquid fuel by a oil transfer pump 4 from an oil tank 3, the liquid fuel is heated by an electric heater and changed into a vaporized gas, and a burner 1 is fed with the vaporized gas and the gas is burnt. An auxiliary heater 5 is arranged at a position heated by the combustion heat of the burner 1 between the oil transfer pump 4 and the carburetor 2. Consequently, the auxiliary heater 5 is heated by the combustion heat of the burner 1 during the combustion of the burner 1, and liquid fuel passing in the auxiliary heater 5 is also heated and fed to the carburetor 2. Accordingly, power consumption in the electric heater installed to the carburetor 2 may be reduced. The auxiliary heater 5 is composed of an inner tube 6 made of a metal, a cushioning material 7 and an outer tube 8 made of ceramics. Item 24 represents a controller controlling the supply and stopping of the vaporized gas.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a liquid fuel combustion device, and more particularly to a liquid fuel combustion device equipped with an auxiliary heater for supplying preheated liquid fuel to a liquid fuel vaporizer. Regarding equipment.

(Prior Art) Conventionally, in a liquid fuel combustion apparatus having a vaporizer equipped with an electric heater for vaporizing liquid fuel, the liquid fuel is heated in advance by the combustion heat of a burner, and the heated liquid fuel is heated. It has been proposed to reduce the power consumption in the vaporizer by supplying it to the vaporizer.

In other words, as shown in FIG. 6, an auxiliary heater is placed at a position where it is heated by the combustion heat of the burner 17 from the oil tank (or oil level regulator) 11 via the oil feed pump 12 and oil feed pipe 13. Liquid fuel is supplied to the container 14, the liquid fuel is preheated by the auxiliary heater 14, and then the liquid fuel is supplied to the vaporizer 15 equipped with an electric heater and heated by the electric heater to gasify it. The vaporized gas of this liquid fuel is burned in a burner 12.

In FIG. 6, reference numeral 16 denotes a control device equipped with a plunger and a nozzle for controlling the ejection of vaporized gas of liquid fuel from the vaporizer 15.

(Problems to be Solved by the Invention) However, in this conventional liquid fuel combustion device, the auxiliary heater 14 is made of a metal with good thermal conductivity, such as an aluminum alloy or a copper alloy. Therefore, as shown in Figure 7,
In order to stably heat the liquid fuel, the oil passage pipe 14b through which the liquid fuel passes must be provided at a distance from the burner 17, and in order to obtain more stable combustion heat than a combustion flame whose combustion amount varies. The heating portion 14a, which is thermally connected to the oil pipe 14b, must be provided in a portion that is directly heated by the combustion heat of the burner 17. For this reason,
The auxiliary heater has to be large, and of course the heat capacity also becomes large, and the thermal response of the liquid fuel in the oil pipe to changes in the combustion amount of the burner 17 becomes poor, especially the rise temperature characteristics of the liquid fuel are poor. There was a problem in that the amount of power consumed by the vaporizer during startup was still large.

In addition, since the heating part 14a is installed in a part that is directly heated by the combustion heat of the burner 17, the temperature reaches a high temperature of 800°C or more, and the metal materials that can be used are limited. There was also the problem of increased costs.

(Object of the Invention) The present invention has been made to solve the above-mentioned problems, and its purpose is to improve the thermal response of the liquid fuel passing through the auxiliary heater, thereby supplying the fuel to the vaporizer. An object of the present invention is to provide a liquid fuel combustion device that changes the liquid fuel produced in response to the combustion heat of a burner and reduces power consumption in a vaporizer.

(Means for Solving the Problems) A liquid fuel combustion device according to the present invention includes a burner, a vaporizer for supplying vaporized gas of liquid fuel to the burner, and a liquid fuel to which preheated liquid fuel is supplied to the vaporizer. In a liquid fuel combustion device comprising: an auxiliary heater disposed at a position heated by the combustion heat of the burner to supply liquid fuel; and an oil pump for supplying liquid fuel to the auxiliary heater. , the auxiliary heater has a double structure consisting of a metal inner tube and a ceramic outer tube, and a buffer material is interposed between the metal inner tube and the ceramic outer tube.

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

FIG. 1 is a schematic diagram showing an embodiment of a liquid fuel combustion apparatus according to the present invention. In Figure 1, ■ is the combustion plate 1
A is a burner consisting of a and a mixing tube 1b, and 2 is a vaporizer equipped with an electric heater such as a ceramic heater or a sheathed heater.

Liquid fuel is supplied to the vaporizer 2 from an oil tank 3 (or a constant oil level device) by an oil feed pump 4, and the liquid fuel is vaporized and gasified by heating with an electric heater, and this vaporized gas is continuously pumped. 1 and combust it. In addition, in Figure 1, 24
is a control device for controlling the supply stop of vaporized gas.

An auxiliary heater 5 is disposed between the oil pump 4 and the vaporizer 2 at a position where it is heated by the combustion heat of the burner 1.

Therefore, while the burner 1 is burning, this auxiliary heater 5 is heated by the combustion heat of the burner 1, and this auxiliary heater 5
The liquid fuel passing through is also heated and supplied to the vaporizer 2. Therefore, power consumption by the electric heater attached to the vaporizer 2 can be small.

As shown in FIG. 2, this auxiliary heater 5 is composed of a metal inner tube 6, a buffer material 7, and a ceramic outer tube 8.

This metal inner tube 6 is preferably made of a material that has excellent heat and corrosion resistance and a small coefficient of linear expansion, such as brass, stainless steel, etc.
Titanium or the like is preferably used.

In addition, the buffer material 7 alleviates thermal conduction of combustion heat of the burner 1 and thermal shock, and also serves as a buffer material for the metal inner tube 6 and the ceramic outer tube 8.
It has the effect of absorbing the difference in linear expansion of the metal inner tube 6 and the ceramic outer tube 8 to alleviate stress applied thereto. As the cushioning material 7, for example, powder of magnesium oxide or diatomaceous earth, or a paper formed from ceramic fiber is suitably used.

The ceramic outer tube 8 has excellent heat resistance and is used to soften the heat conduction of the metal inner tube 6, and for example, one whose main component is alumina, mullite, silicon nitride, silicon carbide, etc. is preferably used. .

This auxiliary heater 5 is constructed by inserting a metal inner tube 6 into a ceramic outer tube 8 which is extruded and sintered into one piece, and inserting a cushioning material between the ceramic outer tube 8 and the metal inner tube 6. Ceramic can be applied by flame spraying, plasma jetting, chemical vapor deposition, or by flame spraying, plasma jetting, chemical vapor deposition, etc.
It is formed by ion beam evaporation or the like.

Experimental Example 1 A ceramic outer tube made of mullite with an inner diameter of φ9 and an outer dimension of φ13 is inserted into a metal inner tube made of stainless steel with an inner diameter of φ6 and an outer dimension of φ8, and a buffer material made of magnesium oxide powder is placed between them. An experiment in which the temperature of the liquid fuel flowing through the auxiliary heater was measured by installing a thermocouple approximately 20 mm downstream of the end of heating section 5 in the metal inner tube, and placing it 60 mm away from the burner nozzle. I did it. In addition, the firepower conditions are 6000Kcal/h and 1500Kcal/h.
It was carried out at two points: 0 Kcal/h.

The results are shown in FIG. As is clear from Figure 3, the temperature of the liquid fuel stabilizes approximately one minute after the burner is ignited, and after that, the temperature of the liquid fuel quickly changes depending on the flow rate and heating power of the liquid fuel, resulting in extremely good temperature control characteristics. It turned out to be.

Experimental Example 2 An experiment similar to Experimental Example 1 was conducted except that the ceramic outer tube of Experimental Example 1 had an inner diameter of φ11 and an outer diameter of φ15.

The results are shown in FIG. As is clear from Figure 4, the temperature of the liquid fuel stabilizes approximately 1 minute after the burner is ignited, and after that, the temperature of the liquid fuel quickly changes depending on the flow rate and thermal power of the liquid fuel, resulting in extremely good temperature control characteristics. It turned out to be.

Comparative Example A comparative experiment was conducted using an auxiliary heater of the type with a heating section shown in FIG. 7 to measure the temperature change of liquid fuel within the auxiliary heater.

The results are shown in FIG. As is clear from FIG. 5, it takes about 12 minutes for the temperature of the liquid fuel to stabilize after the burner is ignited, and it is clear that the temperature control characteristics, especially the start-up characteristics, are significantly worse than that of the present invention. Ta.

(Effects of the Invention) As described above, according to the liquid fuel combustion device of the present invention, the auxiliary heater for supplying preheated liquid fuel to the vaporizer is made of a metal inner tube, a buffer material, and a ceramic material. Since it is made of an outer tube, the auxiliary heater can be placed directly above the combustion flame, which improves the thermal response of the liquid fuel passing through the auxiliary heater, and improves the thermal response of the liquid fuel sent to the vaporizer. It is possible to provide a liquid fuel combustion device in which the fuel changes in response to the combustion amount of the burner, and the amount of power consumed by the vaporizer is reduced, and the auxiliary heater itself can also be extremely miniaturized.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing one embodiment of the liquid fuel combustion device according to the present invention, Fig. 2 is the same (a sectional view of the auxiliary heater portion), and Fig. 3 is a thermal power output of the liquid fuel combustion device according to the present invention. Figure 4 shows the thermal power and the temperature change of the liquid fuel in the auxiliary heater when the diameter of the ceramic outer tube of the auxiliary heater is changed. 5 is a diagram showing the thermal power of a conventional liquid fuel combustion device and the temperature change of the liquid fuel in the auxiliary heater. FIG. 6 is a schematic configuration diagram showing an embodiment of the conventional liquid fuel combustion device. Figure 7 is a cross-sectional view of the auxiliary heater portion. 1.17... Burner 2, 15... Vaporizer 5.14... Auxiliary heater 6... Metal inner tube 7... Cushioning material 8...Ceramic outer tube

Claims (1)

[Claims] a burner; a vaporizer for supplying vaporized gas of liquid fuel to the burner; and a vaporizer disposed at a position heated by combustion heat of the burner for supplying preheated liquid fuel to the vaporizer. In a liquid fuel combustion device comprising an auxiliary heater and an oil pump for supplying liquid fuel to the auxiliary heater, the auxiliary heater has a double structure consisting of a metal inner tube and a ceramic outer tube. A liquid fuel combustion device characterized in that a buffer material is interposed between the metal inner tube and the ceramic outer tube.