JPH0429927B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the configuration of a vaporization section of a combustion device in which liquid fuel is brought into contact with a heated medium to vaporize it and mix it with combustion air.

Configuration of conventional example and its problems In the conventional method of vaporizing liquid fuel using a heat medium, as shown in Fig. 1, a sheathed heater 2 is buried inside a heat medium 1 such as an aluminum die-cast or cast iron molded product. or, as shown in Fig. 2, a heat medium such as an aluminum die-cast or cast iron molded product is brought into contact directly above a flat ceramic heater 3. In either case, the sheathed heater 2, the ceramic heater 3 This was an indirect method in which the heat was transferred to the liquid fuel through the heat carriers 1 and 4 and vaporized. In the case of the above method, the vaporization surface is the heat medium 1,
Since the vaporizer has four inner surfaces, the entire vaporizer becomes large, and a large-capacity sheathed heater 2 or ceramic heater 3 is required to heat the entire inner surface of the heat mediums 1 and 4. In addition, thermal decomposition of the liquid fuel occurs during vaporization, and tar may be deposited and accumulated on the inner wall surfaces of the heat carriers 1 and 4, so there is also a drawback that the vaporization ability decreases when used for a long time. Ta. On the other hand, when a ceramic heater 3 as shown in Fig. 2 is used as a direct vaporizing medium, the vaporizing surface is flat, so the liquid fuel may overflow or the temperature of the surface onto which the liquid fuel is dropped may suddenly rise. Cracks may occur due to a decrease in the temperature.

Purpose of the Invention The present invention solves such conventional problems by providing a compact vaporizer with good start-up by directly using a ceramic heater as a vaporizing medium for liquid fuel, and by raising the outer peripheral edge of the ceramic heater. An object of the present invention is to provide a vaporizer that prevents liquid fuel from overflowing and has increased strength against cracking.

Structure of the Invention In order to achieve the above object, the present invention provides a ceramic heater in which fine heating wires are embedded in a dense heat-resistant ceramic flat plate in a combustion device consisting of a combustion part, a vaporization part, and a blow pipe. The basic configuration is that a raised shape is directly used as the vaporizing medium, and it is installed in the vaporizing section, and the tip of the oil supply pipe is placed so as to face the top surface of the ceramic heater. In this configuration, the liquid fuel dripped onto the top surface of the ceramic heater is prevented from overflowing to the outside by the raised portion at the outer peripheral end of the ceramic heater, and all of the liquid fuel is vaporized on the heater surface. In addition, the combustion air sent from the blast pipe flows from the bottom surface of the ceramic heater along the outer peripheral edge to the top surface, and while being heated by contact with the ceramic heater, it mixes with the vaporized liquid fuel and becomes a premixed gas. is supplied to the combustion section.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the combustion apparatus according to the present invention is shown in FIG. 3 and will be described accordingly.

A heat dissipation tube 9 made of heat-resistant glass is connected to the combustion tube through a heat-resistant O-ring 10 below the combustion tube 8 made of heat-resistant metal, which has a honeycomb shielding plate 5, a honeycomb catalyst body 6, and an ignition heater 7 installed between them. 8. It is fastened between the rectifier tubes 11 by long shaft bolts 12. A premixture inlet 1 is provided at the bottom of the straightening tube 11.
3, and on top of that is a resistance plate 1 for premixture diffusion.
4. Furthermore, a rectifying plate 15 made of punched metal is installed on top of the rectifying plate 15. The vaporization premixing cylinder 16 according to the present invention is connected to the bottom of the straightening cylinder 11, and
7 and the bottom of the vaporization premix cylinder 16 are connected.
At the bottom of the vaporization premixing cylinder 16, a ceramic heater 19 with fine heater wires 18 buried in a dense heat-resistant ceramic flat plate and a ceramic heater 19 with a raised outer peripheral edge is located directly above the outlet of the blast pipe 17. As you do,
It is fixed by a holder 20. Further, the oil supply pipe 21 passes through the vaporization premixing cylinder 16 and is installed so that its tip faces the upper surface of the ceramic heater 19.

Next, the operation of the above configuration will be explained.

When the fine heater wire 18 is energized and the ceramic heater 19 reaches a predetermined temperature, the combustion air introduced from the blower (not shown) flows into the blower pipe 17.
It passes through the lower surface of the ceramic heater 19, passes through the outer peripheral end, and flows into the upper surface of the ceramic heater 19. At the same time, an electromagnetic pump (not shown) is energized and liquid fuel is pumped down on the upper surface of the ceramic heater 19 through the fuel supply pipe 21. The dropped liquid fuel vaporizes as soon as it contacts the top surface of the ceramic heater 19, is uniformly mixed with the incoming combustion air, and passes through the premixture inlet 13 as a premixture.
It collides with the resistance plate 14 and diffuses into the rectifier cylinder 11.
Furthermore, the premixture passes through the catalyst body 6 while being rectified by passing through the rectifying plate 15 . At this point, the premix comes into contact with the ignition heater 7, which is already kept at a high temperature of 800° C. or higher by being energized, and is instantly ignited, forming a film-like fire on the upper surface of the catalyst body 6. The heat transfer of the film fire spreads to the entire catalyst body 6, and the catalyst body 6 reaches the activation temperature, and the catalyst body 6
The catalytic combustion above reaches a steady state. Here, the ceramic heater 19 has a swollen shape at its outer peripheral end, and even if the combustion amount is increased and the amount of liquid fuel dripped is increased, the above-mentioned shape prevents overflow to the outside. It can't happen. In addition, as the amount of combustion is increased, the amount of combustion air introduced also increases, so the lower surface of the ceramic heater 19 is cooled to some extent and the temperature difference with the high temperature section increases.
9. Reinforcement is achieved by raising the outer peripheral edge, and cracking does not occur. On the other hand, when liquid fuel is vaporized for a long time on the ceramic heater 19, fuel components that are thermally decomposed during vaporization adhere as tar as in the conventional example as shown in FIGS. 1 and 2. However, in the case of conventional examples, the entire vaporizing section is made of aluminum die-casting or cast iron, so it is impossible to remove tar at high temperatures.
In the embodiment of the present invention, since the ceramic heater 19 itself is a vaporizing medium, it is possible to raise the temperature to a high temperature and quickly remove tar.

Effects of the Invention According to the combustion apparatus of the present invention, the effects described separately below are achieved.

(1) Since the liquid combustion is directly dripped onto the ceramic heater, a rapid vaporization characteristic is obtained, and even if the liquefied fuel is directly removed, the top surface of the flat plate has a raised outer periphery, so the heat shock is not affected. It can prevent destruction of ceramics.

(2) Since the combustion air flows into the vaporization section while sequentially contacting the bottom, end, and top of the ceramic heater, the combustion air can also be heated by the ceramic heater.

(3) Unlike the conventional method in which the heat source is brought into contact with a metal vaporizing medium, the ceramic heater is temporarily
Since the temperature is raised to a high temperature that stops at about 00°C, tar can be removed without causing corrosion due to oxidation of the vaporizing medium.

[Brief explanation of drawings]

1 and 2 are longitudinal cross-sectional views of a vaporizer in a conventional combustion apparatus, and FIG. 3 is a longitudinal cross-sectional view of an embodiment of the combustion apparatus according to the present invention. 8... Combustion tube, 16... Vaporization premix tube, 17...
...Air pipe, 18...Fine heater wire, 19...Ceramic heater, 21...Oil supply pipe.

Claims (1)

[Claims] 1 Consisting of a combustion section, a vaporization section, and a blower pipe, a ceramic heater is installed inside the vaporizer and directly above the outlet of the blower pipe, with the outer periphery of the top surface of a flat plate raised to a certain height, and the tip of the oil supply pipe The fuel supply pipe is arranged to face the inside of the vaporizing section so as to face the upper surface of the ceramic heater, and the combustion air supplied from the blower pipe is configured to sequentially contact the lower surface, end surface, and upper surface of the ceramic heater. After the combustion has finished, the ceramic heater is temporarily heated to 500~800℃.
A combustion device having means for raising the temperature to ℃.