JPS6118084B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a vaporized liquid fuel in which liquid fuel is atomized, further heated to vaporize it, and then premixed with combustion air and ejected from a burner flame port for combustion. This relates to combustion equipment.

Conventionally, liquid fuel combustion devices have been proposed, such as those in which liquid fuel is vaporized by dropping it onto a preheating heater for vaporization, and those in which centrifugal force from a rotating disk is applied to the surface of the vaporization heater to vaporize it. However, the surface of the vaporization heater that the liquid fuel comes into contact with is constantly cooled and the heating temperature necessary for vaporization cannot be maintained, or the surface of the vaporization heater near the vaporization heater is heated before the vaporized liquid fuel is premixed with the combustion air. There was a risk that it would re-liquefy if it touched a colder wall. Therefore, by increasing the capacity of the preheating heater, even if the liquid fuel necessary for the combustion device is continuously supplied, the temperature drop on the surface of the vaporization heater can be reduced, and the temperature of the wall surface of the vaporization chamber near the vaporization heater can be maintained at a high temperature. Although this is conceivable, there is a disadvantage that the heater and vaporizer must be made larger and the cost also increases.

The present invention has been made to eliminate the above-mentioned drawbacks, and one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway sectional view of a liquid fuel combustion device showing an embodiment of the present invention.

Figure 2 is a sectional view taken along line A-A in Figure 1 above;
3 is a sectional view taken along line B--B in FIG. 1, and FIG. 4 is a sectional view taken along line C--C in FIG. 1. In the figure, 1 is a combustion chamber, 2 is a mixing tube, 3 is a flame port block, and 4 is a combustion air introduction tube with an air intake port 41 on its side wall to take in combustion air from a blower (not shown). I'm trying to put it in there. 5
is a preheating heater for vaporizing liquid fuel, 6 is a liquid fuel supply pipe, and 7 is a linear fine pipe (for example, a diameter of 0.1 mm).
degree) It is a nozzle that injects fuel. The flame port block 3 has a radial slit 31 as a flame port, and is integrally molded with a cylindrical body 32 constituting a vaporization chamber, and this cylindrical body 32 is connected to the preheating heater 5 using a connecting fitting 51, a metal packing 8, etc. The internal space is used as a vaporization chamber 9. This vaporization chamber 9
The preheating heater 5 constituting the connecting fitting 5
A heater 54 made of conductive mica, for example, is mounted inside an inner cylinder 52 made of stainless steel or the like to which the heater 1 is fixed by welding or the like, via a heat-resistant and electrically insulating spacer 53 made of ceramic or the like. The heater 54 is initially tapered so that the outlet side of the vaporization chamber 9 is slightly narrowed so that the liquid fuel injected from the nozzle 7 does not flow out of the vaporization chamber 9 as a liquid. A weir 55 extending from the inner cylinder 52 is provided. The heater 54 and spacer 53 are formed into a predetermined shape by molding, and in the case of this embodiment, as shown in FIG. It has frustum-shaped sides with short side diameters.
This taper forms an inclination of, for example, about 10° with respect to the horizontal, so that oil adhering to the lower part of the inner circumferential surface flows toward the flame port block.

An air hole 10 is bored in the bottom wall of the mixing cylinder 2,
A guide vane 11 for swirling combustion air within the mixing cylinder 2 is installed inside the bottom wall. Reference numeral 12 denotes a secondary air hole for directly introducing a part of the air in the combustion air introduction cylinder 4 into the combustion chamber.

Next, the operation of the vaporized liquid fuel combustion apparatus according to the present invention will be explained.

First, the preheating heaters 5 and 54 are energized, and after detecting by well-known temperature detection means that the surface of the heaters and the inside of the vaporization chamber 9 have reached the optimal temperature (for example, 300°C) for vaporizing the liquid fuel, the combustion air is A blower for blowing air into the introduction tube 4, an igniter, and a liquid fuel supply electromagnetic pump (all not shown) are sequentially operated. At this point, the liquid fuel squirts fine fuel (for example, about 0.1 mm in diameter) straight from the nozzle 7 due to the pressure of the electromagnetic pump, colliding with the back surface 33 of the flame port block 3, which is the target part, and destroying it. At the same time, it is reflected and atomized. The fine liquid cylinder of the atomized liquid fuel moves as shown by the broken line arrow in FIG. 1, touches the vaporization heater 54 which is at an appropriate temperature, and is quickly vaporized. This vaporized fuel gas expands and overflows into the mixing chamber 2 from the rear outlet of the vaporizing chamber 9, and is premixed with the combustion air shown by the solid line arrow taken in from the air introduction tube 4, while being premixed with the flame port block 3. The air is ejected into the combustion chamber 1 through the slit 31 and further mixed with the secondary air ejected from the secondary air hole 12. Then, it is ignited by an igniter (not shown) to start combustion. Then, the burner block 3 is heated by the transfer of thermal energy due to combustion, and this burner block 3 is heated.
When the temperature of the vaporization chamber 9 becomes sufficiently high to the vaporization temperature of the liquid fuel due to the cylindrical body 32 integrally molded with the cylindrical body 32, the electricity to the vaporization heater 54 can be cut off. In the vaporization type liquid fuel combustion device of the present invention, a heater 54 made of Micarex is used as the preheating heater 5. This heater 54 can be placed in the vaporization chamber 9 with the heating element exposed as it is, so the surface area is small. It is possible to construct a preheating heater 5 that is wide and has good thermal efficiency, and is most suitable for use in this type of combustion device. However, the present invention is not limited to the above-mentioned Micarex heater.

In the above-mentioned combustion apparatus, at the initial stage when the vaporization chamber is not sufficiently heated, the liquid fuel injected from the nozzle 7 is not entirely atomized and adheres to the inner circumferential surface of the vaporization chamber 9 as a liquid. Since the heater 54 is inclined downward toward the target section 33, this liquid fuel flows toward the target section 33 and accumulates at the back of the vaporization chamber, so that it does not flow out of the vaporization chamber as a liquid. Moreover, when the amount of liquid fuel that is not atomized increases, the end of the fuel gradually moves from the end on the target section side of the vaporization heater to the end on the vaporization chamber outlet side, so that the fuel in that part As it moves toward the exit side of the vaporization chamber, it is sufficiently heated and vaporized by the vaporization heater, so that it does not flow out of the vaporization chamber as a liquid.

In addition, if some time passes after ignition and the temperature in the vaporization chamber 9 becomes high and the power supply to the vaporization heater 54 is cut off, the temperature inside the vaporization chamber 9 will drop due to the subsequent combustion condition and the electricity will be supplied to the vaporization heater 54 again. Even if this is done, it takes time until the temperature of the vaporization chamber 9 rises to a predetermined temperature. During this time, some of the liquid fuel that is not atomized accumulates on the inner bottom side of the vaporization chamber 9, but because the inner peripheral surface of the vaporization chamber 9 is inclined toward the target section 33, it flows toward the target section 33. During combustion, it comes into contact with the target portion 33, which is at the highest temperature, and vaporizes. Therefore, even if the liquid fuel does not completely vaporize due to collision during combustion, it will definitely vaporize afterwards in the target section 33, so that not only will the liquid fuel not flow out from the outlet, but it will also be vaporized efficiently. It is possible to measure the stability of combustion.

As explained above, according to the present invention, the vaporized fuel is mixed with primary air in the mixing tube, is ejected into the combustion chamber through the flame port block attached to the open end of the mixing tube, and is combusted in the combustion chamber. In the vaporizing liquid fuel combustion apparatus, a vaporizing chamber is formed with the back side of the flame port block as a target part, and a preheating heater is provided on the peripheral surface of the vaporizing chamber, and this preheating heater is connected to the outlet of the vaporizing chamber. The vaporizer chamber is formed into a tapered shape so that the side becomes narrower so that the lower side of the circumferential surface of the vaporization chamber is inclined downwardly with respect to the target portion, and the liquid fuel is formed in a fine linear flow toward the target portion. Since the nozzle that ejects as By efficiently mixing with combustion air flowing out from the opposite direction, blue flame combustion similar to that of ordinary city gas can be obtained from the start of combustion. Further, by providing the target portion near the flame port block, the vaporization chamber can be shortened and made smaller, which is particularly effective when used in a combustion device for high heat generation.

Moreover, the preheating heater provided on the circumference of the vaporization chamber is tapered so that the outlet side of the vaporization chamber is narrower, and the lower side of the circumference of the vaporization chamber is inclined downward with respect to the target area, so that the vaporization chamber is sufficiently large. In the initial stage when it is not heated, the liquid fuel that is not atomized out of the liquid fuel injected from the nozzle 7 flows toward the target part and accumulates at the back of the vaporization chamber, so that it does not flow out of the vaporization chamber as a liquid. Moreover, when the amount of liquid fuel that is not atomized increases, the end of the fuel gradually moves from the end on the target section side of the vaporization heater toward the end on the vaporization chamber outlet side. As the fuel moves toward the exit side of the vaporization chamber, it is sufficiently heated and vaporized by the vaporization heater, so that it does not flow out of the vaporization chamber as a liquid.

Also, during combustion, even if the liquid fuel does not completely vaporize due to collision with the target part, the liquid fuel that has not been atomized or vaporized remains at the highest temperature during combustion due to the taper of the vaporization chamber. Since it is guided to the target area, it will always vaporize even if the preheating heater is not energized. Therefore, not only is vaporization efficient, but also stable combustion can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway sectional view of a liquid fuel combustion device showing an embodiment of the present invention, and FIGS. 2, 3, and 4 are AA, BB, and C--in FIG. 1, respectively. It is a sectional view taken along the line C, and 5 is a preheating heater, 7 is a nozzle, 9 is a vaporization chamber, and 33 is a target portion.

Claims (1)

[Claims] 1. The fuel is configured such that the vaporized fuel is mixed with primary air in a mixing cylinder, and is ejected into a combustion chamber through a flame port block attached to the open end of the mixing cylinder and combusted in the combustion chamber. In the vaporization type liquid fuel combustion apparatus, a vaporization chamber is formed with the back side of the flame port block as a target part, and a preheating heater is provided on the peripheral surface of the vaporization chamber, and the preheating heater is arranged so that the outlet side of the vaporization chamber is narrow. a nozzle formed in a tapered shape so that the lower side of the circumferential surface of the vaporization chamber is inclined downward with respect to the target section, and which jets liquid fuel as a fine linear flow toward the target section; A vaporizing liquid fuel combustion device characterized in that a vaporizing liquid fuel combustion device is provided opposite to the outlet of the vaporizing chamber.