JPH01269808A - Fuel gasification device - Google Patents

Abstract

PURPOSE:To increase a temperature rising speed of fuel and shorten gasification time as well, by installing a heater exposed inside a carburetor, providing a thin film of metal fiber or ceramic fiber on the surface of this heater, and using this thin film for the main gasification surface of fuel. CONSTITUTION:Kerosene and combustion air are supplied into a carburetor 8 where they are gasified, mixed and flow out from a mixing plate 14 as a premixed gas. Then, a thin layer 18 which covers the surface of a heater 9 is used as a main gasification surface for the kerosene. The thin layer 18, which is made of aluminum fiber for example, is provided with an outer surface area several times larger than that of a plate heater 9. A temperature rising speed on the surface of the heater 9 is markedly higher due to a small heating capacity of the heater 9. Specifically, it can reach the degree of temperature required to gasify kerosene in two seconds. Since the thin layer 18 is made of aluminum whose heat conductivity is excellent, the temperature rises quickly. Furthermore, it is provided with a proper temperature distribution, which makes it possible to prompt the gasification of kerosene and facilitate the stabilization of fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fuel vaporization device for vaporizing liquid fuel such as kerosene.

2. Description of the Related Art A conventional fuel vaporization device has a configuration as shown in FIG. 3, and is generally installed in a home hot air fan or the like. In the figure, reference numeral 1 denotes a vaporizer made of aluminum casting, and a sheathed heater 2 in which a nichrome wire is enclosed in a pipe together with an insulating material is cast into the upper part. In addition, an air pipe 3 is attached to the opening on the side, and a fuel nozzle 4 for spouting kerosene as fuel is inserted into the carburetor 1 from the outside of the air pipe 3 near the center line of the pipe. ing. A mixing plate 5 for promoting the mixing of air and fuel gas is provided at the top opening of the carburetor 1, and a burner 6, which is formed of a cylindrical punched plate and has a wire mesh wrapped around its outer periphery, is mounted. .

In the above configuration, when the sheathed heater 2 is energized, the heater 2 first generates heat, and then the entire vaporizer 1 becomes high in temperature due to heat conduction. Although not shown, the temperature of the vaporizer 1 is normally controlled by a control circuit to around 280° C., which is the appropriate evaporation temperature for kerosene. On the other hand, combustion air is pressurized by a fan or the like (not shown) and is supplied into the carburetor 1 through an air pipe 3.

At the same time, the kerosene ejected from the fuel nozzle 4 becomes droplets and collides with the side surface of the vaporizer 1, and becomes high in temperature due to heat transfer on the surface of the vaporizer 1, where it evaporates and vaporizes. This vaporized gas is mixed with combustion air, guided into the interior of the burner 6 via the mixing plate S, and finally ejected from the wire gauze of the burner 6 and combusted.

In another conventional example, as shown in FIG. 4, there is a fuel vaporizer in which the vaporizer 1 is made of conductive ceramics and is connected to a power source so that electricity can be supplied near the vaporization mixing chamber T. -172917).

Problems to be Solved by the Invention However, with the above configuration, first of all, since the heat capacity of the vaporizer is large, the temperature at which the vaporizer should be set (for example, for kerosene, the temperature
In order to raise the temperature to 0°C, it was necessary to energize the heater for about 2 minutes or more.

There was a problem in that it took a long time from the start of operation of the vaporizer to the start of vaporization. Therefore, for example, if this vaporizer is installed in a home hot air fan, etc., the power switch must be turned off.
NL, but if you wait more than 2 minutes, it will vaporize and not burn, so there is a problem that the desired warm air is not generated and the room temperature rises slowly. In addition, the conventional example
In the device described in Japanese Patent No. 172917, the heat generating portion becomes non-uniform, the temperature distribution of the vaporizer becomes uneven, the vaporization tends to become unstable, and there are also problems with its insulation properties.

The present invention is intended to solve such conventional problems, and aims to shorten the vaporization time by significantly increasing the temperature rise rate of the main fuel vaporization surface while maintaining the fuel vaporization performance in a good state. .

Means for Solving the Problems In order to solve the above problems, the fuel vaporizer of the present invention has a heater exposed inside the vaporizer, and a contact area between the heater and the vaporizer is made small to reduce thermal resistance. A thin layer of metal fibers or ceramic fibers is provided on the surface of the heater, and this thin layer and its vicinity are used as the main fuel vaporization surface.

With the above-described configuration, the present invention uses the surface of the heater, which has a high temperature rise speed, as the main vaporization surface, so it is possible to significantly shorten the vaporization start-up time, and
Kerosene is supplied to a thin layer of metal fibers or ceramic fibers provided on the heater surface, so the thin layer has a certain temperature distribution and a large surface area, which promotes and stabilizes the vaporization of the kerosene. It also plays the role of a heat shock buffer and can improve heater durability.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. Figure 1 shows a kerosene vaporizer. 8 is a vaporizer made of aluminum, and a heater 9 made of silicon nitride is inserted into the bottom of the vaporizer.

The heater 9 is supported by the vaporizer 8 by a holder 1o. Further, a primary air supply port 11 is provided on the side of the carburetor 8, and kerosene is supplied from this firebox air supply port 11 through the entire fuel nozzle 12 to the surface of the heater 9 in the carburetor θ. vaporized and - mixed in the carburetor 8 with the combustion air supplied by the firebox air duct 13 and exits as premixed gas through the mixing plate 14 and is supplied to the burner section (not shown) . Reference numeral 15 denotes a pressurizer, which is installed between the carburetor 8 and the blower pipe 13, and - by narrowing down the opening area of the firebox air supply port 11, the pressure of the pressurization chamber 16 formed by the pressurizer 15 is increased. is significantly higher than the pressure inside the vaporizer 8. Further, the insertion part 9 of the heater 9 is provided in the pressurizing chamber 16, and 17 is the pressurizing chamber 16 of the heater 9.
This is the seal part. A thin layer 18 made of aluminum fiber covers the upper and lower surfaces of the heater 9.

In the above configuration, kerosene and combustion air are supplied into the vaporizer 8, vaporized and mixed, and flow out from the mixing plate 14 as a premixed gas. At this time, the surface of the heater 9 is the main vaporization surface of the kerosene. A thin layer 18 covering the is utilized. The heater 9 has a titanium nitride resistor coated with silicon nitride, and has a heat capacity of about 2 to 3 cal! /”C
, and has a flat plate shape with a surface area of about 15 am2. Therefore, the heater 9 uses 5.2 g/m1n of kerosene (32 g/m1n in calorific value).
00 kcml/h), and the thin layer 18 has a surface area several times that amount. When the input to the heater 9 is eoow, the temperature increase rate on the surface of the heater 9 is also extremely fast as shown in Figure 2 because the heat capacity of the heater 9 is small, and is approximately 2 degrees, which is necessary for vaporizing kerosene. temperature (approximately 280'C). Further, since the thin layer 18 is also made of aluminum with good thermal conductivity, the temperature rises quickly, and since the thin layer 18 has an appropriate temperature distribution, the vaporization of kerosene is easily promoted and stabilized. On the other hand, the heater 9 is supported by the holder 10 so that no extra force is applied to it, and the thin layer 18 acts as a buffer material to relieve heat shock, so it has a structure that is resistant to thermal stress. Since the contact area between the heater 9 and the vaporizer 8 is small, the thermal resistance is extremely large, making it difficult for the heat input to the heater 9 to be conducted toward the vaporizer 8, which causes a rise in the surface temperature of the heater 9. There is no obstruction. On the other hand, the kerosene supplied from the fuel nozzle 12 to the surface of the heater 9 travels along the surface of the heater 9 and tends to leak out from the insertion portion 9m of the heater 9, that is, near the holder 10, in a liquid or gas state. In the embodiment, the opening area of the firebox air supply port 11 is constricted to make the pressure loss the largest among the air flow path diameters, so the pressure in the pressurizing chamber 16 located upstream thereof is lower than that of the carburetor 8. The pressure becomes significantly higher than the pressure inside, and serves to prevent kerosene from flowing out of the vaporizer 8 from the vicinity of the holder 10.

As a result, it is possible to provide a fuel vaporizer that has a fast start-up speed, without causing unburned gas or liquid of kerosene to leak outside, and without causing unpleasant odors or the risk of fire due to fuel leakage. Become.

Effects of the Invention As described above, the fuel vaporizer of the present invention provides the following effects.

(1) Since the surface of the heater, which has a small heat capacity and a high contact resistance with the vaporizer, etc., is used as the main vaporization surface, fuel can be vaporized in an extremely short time compared to conventional configurations.

(2)) Since the heater insertion part is provided in the pressurizing chamber and the pressure is higher than the pressure inside the vaporizer, the fuel does not leak to the outside and a safe and odorless vaporization state can be obtained at all times.

(3) Since the thin layer plays the role of a heat shock buffer, stress is applied to the heater, improving the durability of the heater and making it extremely reliable.

(4) Since the fuel mainly vaporizes on the high-temperature heater surface and thin layer, the formation of tar, etc. is extremely small, the vaporization area is large, and the vaporization surface has an appropriate temperature distribution, so vaporization is accelerated. stabilized.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a partial sectional view of a fuel vaporizer according to an embodiment of the present invention, Fig. 2 is a rise temperature characteristic diagram of the same heater, and Figs. It is a partial sectional view of a vaporization device. 8... Carburizer, 9... Heater, 12.
... Fuel nozzle, 16 ... Pressurization chamber, 18
...Thin layer. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure No. 3 (Fig. 4)

Claims (1)

[Claims] a fuel supply means for supplying liquid fuel; an air supply means for supplying combustion air; and introducing the combustion air into the interior;
and a vaporizer for vaporizing the liquid fuel, a heater is installed exposed inside the vaporizer, a contact area between the heater and the vaporizer is made small to increase thermal resistance, and
A fuel vaporization device in which a thin layer of metal fibers or ceramic fibers is provided on the surface of the heater, and this thin layer and its vicinity are used as the main fuel vaporization surface.