JPH0137643B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vaporizer that vaporizes liquid fuel, mixes it with combustion air, and supplies an air-fuel mixture to a combustion section.

Structure of a conventional example and its problems A conventional vaporizer of this type is shown in FIG. A fuel supply pipe 5 and an air supply pipe 6, which are connected to a fuel pump 3 and a combustion fan 4, respectively, are opened in the side wall of a pot-shaped vaporization cylinder 2 heated by a heater 1. Further, a mixing plate 8 in which a mixture passage 7 is formed and a burner head 10 in which a burner port 9 is formed are arranged at the upper opening of the vaporizing cylinder 2. The vaporization chamber 11 is divided,
A mixing chamber 12 is defined between the mixing plate 8 and the burner head 10. In the above configuration, the heater 1 is energized to heat the vaporization tube 2, and when the temperature reaches a predetermined temperature, the fuel pump 3 and combustion fan 4 are activated to supply liquid fuel and combustion air to the vaporization chamber 2.
Supply to 1. The liquid fuel that has entered the vaporization chamber 11 is vaporized on the inner wall surface of the vaporization cylinder 2, mixed with combustion air, and enters the mixing chamber 12 through the mixture passage 7. The air-fuel mixture that has entered the mixing chamber 12 is further mixed uniformly there, is ejected from the flame port 9 of the burner head 10, and is ignited by an ignition device (not shown) to cause combustion.

However, in the above conventional example, the vaporization wall temperature is as low as about 230°C to 280°C, and when fuel that easily turns into tar, such as denatured oil or heavy oil, is vaporized, tar adheres to the inner wall of the vaporizing cylinder 2, causing ignition. There was a problem that the odor was strong after the fire was extinguished. In general, the components contained in fuel that easily turn into tar are high boiling point components, and the formation and adhesion of tar can be prevented by setting the vaporization wall temperature to a high temperature, such as the film boiling temperature of the fuel or higher. Stable vaporization was not possible when the temperature was raised. That is, the fuel sent out from the fuel supply pipe 5 collides with the side wall surface 13 (hereinafter referred to as the collision surface) opposite to the opening of the fuel supply port 5 of the carburetor 2, but due to the high temperature of the wall surface, some The majority of the particles are dispersed as fine particles, which fall to the bottom of the vaporizer cylinder and are vaporized. However, since the bottom surface is also under high-temperature film boiling conditions, the fallen fuel particles roll while floating on the vapor layer formed in the boundary layer with the vaporization bottom surface, and tend to coalesce into giant particles. When the fuel becomes large particles in the vaporization chamber 11, vaporization becomes irregular and stable vaporization is not carried out, and combustion in the burner head 10 may cause flames or, in extreme cases, misfires.

Purpose of the Invention The present invention solves the above-mentioned problems in the conventional example, and aims to prolong the life of the vaporizer by preventing the formation and adhesion of tar during the vaporization of denatured oil and heavy oil. The purpose is to obtain a vaporized state.

Structure of the Invention In order to achieve this object, the present invention provides a vaporization cylinder maintained at a temperature higher than the film boiling temperature of fuel, a combustion air supply means for supplying combustion air into the vaporization cylinder in a swirling direction, and a fuel supply means. In addition, a large number of protrusions are provided on the vaporizing surface, mainly the inner bottom surface of the vaporizing cylinder, radially with respect to the center of the vaporizing cylinder, and the collision surface with the fuel provided on the inner wall of the vaporizing cylinder is a smooth surface. It is a vaporizer.

With this configuration, the fuel particles that are split and scattered on the high-temperature collision surface and fall onto the vaporization surface are rolled by the swirling air flow on the bottom surface of the vaporization cylinder (especially the outer periphery of the bottom surface) due to the protrusions, and coalesce into each other. The particles are vaporized as they are on the high-temperature vaporizing surface, resulting in stable vaporization, and the high-temperature vaporization prevents the formation and adhesion of tar, thereby extending the life of the vaporizer.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 to 5. In the drawings, parts that are the same as those in FIG. 1 are designated by the same numbers, and explanations thereof will be omitted.

The fuel supply pipe 5 and the air supply pipe 6 provided on the side wall of the carburetor tube 2 are installed so as to supply fuel and combustion air to the vaporization chamber 11 in the swirling direction, and the vaporization surface of the carburetor tube 2 has a cross-sectional shape. A large number of trapezoidal projections 100 as shown in FIG. 4 or hemispherical projections 100 as shown in FIG. 5 are provided radially with respect to the center of the vaporizer cylinder 2 at intervals of 4 to 5 mm. Note that the collision surface 13 of the fuel delivered from the fuel supply pipe 5 is a smooth surface.

Next, the operation will be explained. When the heater 1 is energized and the vaporization tube 2 is heated to a predetermined temperature, the combustion fan 4 and the fuel pump 3 are activated, and combustion air and fuel are sent into the vaporization chamber 11 from the air supply pipe 6 and the fuel supply pipe 5 in the swirling direction. sent to. The delivered fuel collides with the collision surface 13, which is smooth and maintained at a temperature higher than the film boiling temperature of the fuel, and is uniformly split and scattered to scatter on the vaporization surface (mainly the bottom surface) as fine particles. Furthermore, due to the swirling flow caused by the combustion air, the fuel particles moving along the side wall of the carburetor cylinder 2 collide with the protrusions 100 provided on the side wall, but since the protrusions 100 are also at a high temperature, the fuel particles split again, and further. It becomes fine particles and falls to the bottom. If there are no protrusions on the bottom, the fine fuel particles that have fallen to the bottom will roll in the swirling direction due to the swirling airflow and coalesce with each other, forming giant particles that rotate around the outer periphery of the bottom and make vaporization unstable. Because of the protrusions 100 provided radially with respect to the center of the vaporizer cylinder, the range of movement of the fuel particles is limited and not only is it possible to prevent the fuel particles from coalescing into giant particles, but once the giant particles are formed, the protrusions 100
By colliding with the particles, the particles will split again and be scattered again as fine particles on the vaporization surface. In addition, the fuel particles move around on the vaporization surface of the concave portion between the protrusions while floating on the vapor layer interposed in the boundary layer between the protrusions 100 and the fuel particles. Heat transfer is promoted, resulting in rapid and stable vaporization. If the distance between these protrusions is too wide, the continuously falling fuel particles will coalesce into large particles, which will lengthen the vaporization time and make it impossible to obtain stable vaporization.According to experiments, however, as shown in Figure 6. The distance between the protrusions is 1 to 5.
If mm, the diameter of fuel particles formed in the concave part of the vaporizing surface is 1~
The particle size is 1.5 mm or less, and the time required for vaporization and evaporation is 1 second or less for particles of this size. Vaporization/
If the evaporation time is 1 second or less, there will be no vaporization delay in the vaporizer, and problems such as standing flames during combustion will not occur.

FIG. 7 shows another embodiment of the present invention,
The protrusion 101 is formed in a radial and spiral shape with respect to the center of the vaporizing cylinder, and its direction is the same as the swirling direction of the combustion air. In this configuration, the protrusion 1 prevents the fuel particles scattered on the collision surface 13 and falling onto the bottom surface of the vaporizer cylinder from rotating around the outer circumference of the vaporizer cylinder due to the swirling flow caused by the air flow.
01 to actively guide it to the center,
Compared to the embodiment shown in FIG. 3, vaporization is performed over a wider vaporization surface, so the vaporization load is reduced and the tar suppression effect can be further increased.

Effects of the Invention As described above, the present invention includes a vaporization cylinder maintained at a temperature higher than the film boiling temperature of the fuel, a combustion air supply means for supplying combustion air into the vaporization cylinder in a swirling direction, and a fuel supply means. The vaporizing surface, which is mainly the inner bottom surface of the vaporizing cylinder, is provided with a large number of protrusions radially from the center of the vaporizing cylinder, and the collision surface with the fuel provided on the inner wall of the vaporizing cylinder is a smooth surface.

Therefore, in order to achieve good vaporization above the film boiling temperature of the fuel, where it is difficult to vaporize the fuel, the fuel is split and atomized on the smooth collision surface provided on the inner wall of the vaporization cylinder, and the bottom surface is The protrusions prevent fallen fuel particles from coalescing with each other and causing them to become large, while rapidly vaporizing them due to the swirling air flow. Therefore, good vaporization can be achieved at high temperatures with significantly less tar formation.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view showing a conventional vaporization device;
The figure is a longitudinal cross-sectional view of a vaporizer according to an embodiment of the present invention, FIG. 3 is a cross-sectional view taken along line AA in FIG. 2, and FIGS. 4 and 5 are respectively the vaporizer of the present invention in FIG. FIG. 6 is a longitudinal cross-sectional view showing an example of the main part of the device, FIG.
The figure is a cross-sectional view showing another embodiment of the vaporizer of the present invention. 1... Heater, 2... Vaporizer cylinder, 3... Oil supply pump, 4
...Combustion fan, 13...Collision surface, 100...Protrusion.

Claims (1)

[Claims] 1. A vaporizer cylinder maintained at a temperature higher than the film boiling temperature of the fuel;
It includes a combustion air supply means for supplying combustion air into the vaporization cylinder in a swirling direction, and a fuel supply means. A vaporizer that has protrusions and has a smooth surface on the inner wall of the vaporizer cylinder that collides with the fuel. 2 Claim 1 in which the protrusion is substantially linear
Vaporizer as described in section. 3. The vaporizer according to claim 1, wherein the protrusions are arranged in a spiral shape so as to guide the swirling air flow within the vaporizer cylinder to the center of the vaporizer cylinder.