JPS5831202A - Wick - Google Patents

Abstract

PURPOSE:To obtain a wick which is almost free from an influence of tar, by mainly composing the vaporizing part of a wick with heat-resistant fiber of below 2 microns in size. CONSTITUTION:The vaporizing part 3 of a wick is composed of fiber below about 2 microns in diameter. Kerosene is vaporized from the surface of a fuel vaporizing part 3. In case that kerosene, mixed with an oil of different quality, or degenerative kerosene is used, tar is accumulated on the surface of a vaporizing part 3, but most of tar is vaporized by thermal decomposition, as soon as it is accumulated on the surface. Because the vaporizing part 3 is made of porous material, unfavorable influence such that remarkable lowering of combustibility will scarcely occur in a combustor, even if some quantity of tar will remain on the surface. By composing the fuel vaporizing part with such a fiber, unfavorable influence by tar to a wick can largely be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lamp wick used in a liquid fuel combustor, and its purpose is to suppress the generation and accumulation of tar-like substances in the fuel vaporization part of the lamp wick, and to achieve stable combustion over a long period of time. The goal is to provide a wick that can maintain the

BACKGROUND ART A so-called siphon-vaporizing combustor, which sucks up liquid fuel by the capillary action of a lamp wick and vaporizes the liquid fuel from the surface of a fuel vaporizing section and burns it, is widely used in oil stoves, oil stoves, and the like.

In this type of combustor, the fuel vaporization section is exposed to a high temperature and oxygen-containing atmosphere, so that during combustion, some of the fuel contained in the fuel vaporization section becomes tarry due to oxidation double polymerization reaction, etc. This forms a substance that accumulates in the fuel vaporization section. In particular, if trace amounts of high boiling point components are mixed into fuel 11 (
For example, if machine oil, diesel oil, salad oil, etc. get mixed into kerosene), or some of the fuel components change in quality (for example, if kerosene is stored at high temperatures or under direct sunlight for a long period of time, oxides, peroxides, resins, etc.) In the case where tar-like substances are produced or the like, the amount of tar-like substances produced and accumulated increases significantly.

When this tar-like substance accumulates in the fuel vaporization section, the capillary tubes on the surface or inside the fuel vaporization section are blocked, thereby inhibiting fuel suction and vaporization. As a result, the amount of fuel vaporized decreases abnormally, and the air-fuel ratio in the combustion chamber collapses, causing odor, soot, and harmful carbon monoxide to be emitted. In addition, at the time of ignition, the tar-like substance causes the temperature of the fuel vaporization part to rise rapidly, preventing an increase in the amount of fuel vaporization, and it takes an extremely long time to reach stable combustion. Odor, soot,
- Large amounts of carbon oxide, etc. are generated3.

Was. Furthermore, a tar-like substance dusted the wick and its dangerous support.

In order to eliminate these conventional drawbacks, the present invention suppresses the generation and accumulation of tar-like substances (hereinafter referred to as tar).One embodiment of the present invention will be described below with reference to the accompanying drawings.

A partial cross-sectional view of a main part of an embodiment of the present invention is shown in FIG. 1, and in this FIG. Instead, it contains small amounts of inorganic and organic binders. 2 is a suction wick made of polypropylene, cotton, etc., and 3 indicates a location corresponding to the vaporization part of the fresh grass 1. 4
6 is a sewing thread, and 6 is an adhesive tape. Hiko: The heat-resistant fiber mentioned above is a silica/alumina ceramic fiber.

Alternatively, glass fiber, rock fiber, etc. are suitable. In this configuration, liquid fuel is stored in a tank (not shown)
It is sucked up from inside by the suction wick 2, is similarly sucked up by the fresh grass 1, and is vaporized from the surface of the vaporizing section 3.

The cause of malfunctions such as a decrease in combustion amount is the combustion part 3.
1: As mentioned above, it concerns where the tar is generated. In other words, the tar generated on the surface of the fuel vaporization section 3 is gradually thermally decomposed and becomes porous because the atmosphere outside it is extremely high temperature due to the combustion heat of the combustor. This is just the same situation as if the volume of the fuel vaporization section 3 had increased slightly, and it would not be much of a problem as long as it did not increase at the end of the rod. A particular problem arises when tar is generated at a location slightly inside the fuel vaporization section 3 from the surface. At this time, since it is inside the wick, the temperature tends to rise, and the generated tar is not thermally decomposed and accumulates, blocking the pores that allow fuel to be sucked in and vaporizing the fuel. Due to the cracks in the surface of part 3, fuel cannot reach it. As a result, the amount of combustion (vaporization) decreases, the air-fuel ratio changes, and various impurities occur.
, -... The condition will appear. Where the tar is generated is simply because the fuel is in the fuel vaporization section 3.
This depends on where the gas is vaporized.

In other words, when tar is being vaporized on the surface, tar is generated on the surface, and when tar is being generated slightly inside, it is being vaporized somewhat internally. Chemically, the production of tar occurs from an oxidation reaction, and this reaction is a solid phase,
It can be said that it becomes most active when the three phases of liquid and gas coexist, and when it is vaporized. Therefore, if the tar is vaporized on the surface, the generation of tar can be minimized, and the above-mentioned problems can be made much less likely to occur. And where does the fuel vaporize?
In other words, it can be said that this is due to the suction ability near the surface of the fuel vaporizing section 3, that is, the ability to supply from the inside to the surface. When the combustor is in use, the temperature of the fuel vaporization section 3 is around 200'C, especially at the surface.
01? : Increased to a certain extent. -Actual fuel is main core 1
．． The fuel is sucked up by the capillary action of the suction wick 2, and its suction (supply) speed is determined by the properties and temperature of the fuel and the diameter of the pores. For example, in this embodiment, kerosene is used as the liquid fuel, and FIG. 2 shows the temperature dependence of the suction speed at a height of 100 mm. As the temperature rises:
Therefore, the viscosity of kerosene tends to decrease and the rate of suction increases, while the surface tension decreases as the temperature rises, so the pressure in the suction sump decreases and the rate tends to decrease. These trends show that in the temperature range up to about 1601:1, the influence of viscosity becomes stronger as the temperature rises, and the wicking speed increases. In a temperature range higher than that, the influence of surface tension becomes greater and the suction speed decreases rapidly. These changes become larger as the pore diameter becomes larger, and become smaller as the pore diameter becomes smaller. For example, when the pore size (diameter) is 40 microns, the wicking rate is 1
It reaches a maximum value around 00°C, rapidly decreases at temperatures below that, and at 250°C, the suction speed becomes almost zero. Furthermore, when the pore diameter is 10 microns, the value of 7/·-1 is smaller than when it is 40 microns, but it reaches its maximum value around 160°C, and at higher temperatures,
As it increases, it gradually decreases.

At this time, since the rate of decrease is gradual, the wicking rate is 240°C for pore diameters of 40 and 10 microns.
Nearby, it reverses and becomes larger at 10 microns. From Figure 2, when the temperature of the wick is around 27o0C,
In pores of 20 microns or more, kerosene becomes difficult to flow out as a liquid to the surface of the fuel vaporization section. In other words, tar vaporizes on the inside rather than on the surface, and tar is more likely to accumulate on the inside than on the surface, resulting in the above-mentioned problems. This phenomenon does not occur below 10 microns, and the kerosene is vaporized on the surface. Now, regarding the relationship between the strand diameter of the fiber and the pore diameter,
Strictly speaking, the pores in this case have a three-dimensional structure and are not cylindrical in shape, but by measuring the wicking rate at room temperature, it can be determined approximately how many micrometers the pores correspond to. It turns out that. According to our measurements, when the center of the wire diameter distribution is 3 microns and the porosity is 90 inches, it corresponds to a pore of approximately 15 microns, and when the center of the wire diameter distribution is 1 micron, the porosity is 90 inches. It was found that 90% corresponds to 5 micron pores. This fact is shown in the pore diameter shown in Figure 3, which was also confirmed by measuring the pore diameter distribution using mercury porosimetry.

From the following two points, it was decided that the fibers in the wick vaporizing section 3 should be composed of approximately 2 microns or less (10 microns or less in linear pore diameter) so that the kerosene would be vaporized on the surface of the fuel vaporizing section 30. Therefore, even if foreign oils or denatured oils are used, they will accumulate on the surface and will be thermally decomposed at the same time as they accumulate. As a result, a significant effect can be obtained in that problems such as a significant deterioration in the performance of the combustor almost never occur.

As described above, in the present invention: No. 1, since tar is generated on the surface of the fuel vaporizing section, the adverse effects of tar can be minimized.

Figure 1 is a partial cross-sectional view of one embodiment of the present invention. Figure 2 is a characteristic diagram showing the temperature dependence of the suction speed. Figure 3 is a graph corresponding to the wire diameter. FIG. 3 is a diagram showing the relationship with pore diameter.

3...Fuel vaporization section.

Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] A lamp wick, characterized in that it absorbs liquid fuel and vaporizes the liquid fuel in a vaporizing section, - at least the vaporizing section is mainly composed of heat-resistant fibers having a diameter of 2 microns or less.