JPS6014004A - Liquid fuel combustion device - Google Patents

Abstract

PURPOSE:To prevent and reduce adhesion of soot to a middle cylinder surface and to promote periodical forced evaporation of soot and tar, by installing a means, which varies the injecting position of the air, to the inside of the middle cylinder. CONSTITUTION:After the mixture ratio and the temperature of fuel attain the specified values respectively as the fuel is diffused and mixed by means of a swirl flow produced in a combustion chamber 6 by means of the air injected through nozzles 15 formed in the middle and the lower part of a middle cylinder 10, the fuel is ignited for combustion. Because of an sufficient air being fed in a premixing area (b), the flame formed during such transistion combustion period forms a swirl diffusion flame having high luminance, in the middle part of the middle cylinder 10. This causes a portion in the vicinity of a flame forming part, the bottom part 9' of the wall surface of the combustion chamber 6, and the bottom part 9 of the combustion chamber to be heated by radiation and a flame having a high temperature during a time between ignition and a point of time when they are increased in temperature to a specified value, and causes an adhered unburnt content to be forcibly decomposed and evaporated for disappearance. This permits prevention of production and adhesion of soot.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a liquid fuel combustion device that further improves the combustion performance of a heat source device used as a small-sized domestic hot water supply and space heating device, and improves the performance of each device. .

Conventional Structure and Problems Conventionally, this type of combustion apparatus has been structured as shown in FIG. That is, in the combustion chamber 6, a middle cylinder 10 having a large number of air ejection holes 15 on the side wall and an auxiliary combustion cylinder 11 are arranged substantially concentrically, and a liquid fuel atomizing means 3 is introduced into the combustion chamber 6. is present. The fuel is supplied from the atomization means 3, and the combustion air is supplied to the bottom 9 of the combustion chamber by the blower mechanism 21.
The air is continuously supplied to the combustion chamber 6 from the air injection holes 15 on the middle cylinder 10 through a wind box 22 connected to the back surface of the cylinder. After the initial diffusion combustion, the subsequent fuel particles immediately vaporize at a high speed due to the combustion heat, promoting diffusion mixing and exiting the air jet hole 15 in the upper part of the middle cylinder 10 in a premixed state.
In this type of combustion device that performs flame holding and φ stage combustion, a stable flame is formed for the first time by the total amount of air supplied from each nozzle 15 on the middle cylinder 10, and the combustion characteristics are satisfied and maintained. be. Therefore, during the transitional combustion period from ignition to steady combustion with stable blue flame formation, there is a shortage of combustion air ejected from the middle and lower nozzle holes 15 on the middle cylinder 10, and the atomization means. 3, the fuel is insufficiently mixed with the atomized particles, and while diffusive combustion is performed, new air is supplied, and the flame swirls upward in the combustion chamber 6. As a result, the flame generating soot comes into contact with the surface of the middle cylinder 10, which is the center of the swirling flow in the combustion chamber 6, and deposits soot. In addition, due to the simple configuration, the combustion area a, the premixing area, and the recirculation area C are adjacent to each other in the same combustion chamber 6, so that during the steady combustion period, unvaporized fuel particles adhere to the vicinity of the bottom 9 of the combustion chamber. Then, the premixture flows into the recirculation region C, where the vaporized fuel is cooled and reliquefied on the wall surface and adheres to the bottom of the wall surface. The flame temperature and radiation are also lower than in the instant flame of diffusion combustion, and the deposited fuel is slowly polymerized. Due to the repeated combustion operations exhibiting the above-mentioned phenomena, the growth and layering of the attached soot and the polymerization and layering (tar) of the attached fuel progress. In this way, the adhesion and growth of soot and tar to the internal components of the vessel causes unevenness in the amount of vaporization and diffusion mixture during steady combustion. This resulted in various phenomena such as an increase in combustion noise due to unstable flame holding and a deterioration in the properties of the exhaust gas (particularly ρO, HC, odor, etc.) during ignition and extinguishing.

Purpose of the Invention In view of the above-mentioned drawbacks, the present invention aims to (1) suppress and alleviate soot adhesion on the inner cylinder surface, and (2) reduce formed and adhered soot and tar (unburned content, polymerized fuel, etc.). The purpose is to promote periodic forced vaporization and burn out.

Structure of the Invention In order to achieve the above object, the present invention is provided with means for varying the air ejection position inside the middle cylinder.

With the above configuration, by directing the air supplied from each nozzle on the middle cylinder to the middle and lower parts for a certain period of time during initial combustion, the flame temperature and radiation are high in the middle and lower parts of the middle cylinder. A diffusion flame (luminous flame) is formed, and the initial diffusion flame caused by soot generation due to lack of air and insufficient mixing is eliminated. As a result, the generation of soot and its adhesion on the surface of the inner cylinder are suppressed and alleviated, and the high temperature promotes the decomposition and vaporization of the cooled portion of the reliquefied fuel generated on the wall and bottom portions of the reliquefied fuel during the steady combustion period. In this way, self-cleaning is performed each time combustion is repeated, and the exhaust gas (C○) is generated during ignition and extinguishing.

It is possible to maintain the characteristics of HC, odor, etc.) and to maintain stable flame stability during the steady combustion period.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

In FIGS. 2 and 3, a fuel pump 2 and a spiral injection valve 3 as an atomization means are connected to a fuel tank (not shown) via an oil pipe 1. 3 and the ignition electrode 4 are included in the support tube 5, and the combustion chamber 6
is being faced.

The can body 7 is formed of an inner shell 8 and an outer shell 8', and defines the combustion chamber 6 inside. Moreover, the bottom part 9 of the combustion chamber 6
There is a middle cylinder 10 in the middle part, and an auxiliary combustion pipe 11 in the outer circumference of the middle cylinder 10.
has been erected. and a wall opening 1 of the combustion chamber 6.
The tips of the spiral injection valve 3 and the ignition electrode 4 are exposed to the combustion chamber 6 via the spiral injection valve 3.
The auxiliary combustion cylinder 11 located opposite to the auxiliary combustion cylinder 11 is provided with a spray port 13 having a sufficiently large hole to prevent the spray particles of fuel from colliding with the auxiliary combustion cylinder 11.
A large number of circulation holes 14 are provided. And the middle cylinder 10
A large number of air ejection holes 15 are provided around the side wall of the air conditioner 15 in a tangential direction or gradually from the tangential direction to the right angle direction from the bottom to the top. Further, as shown in FIG. 3A, the middle cylinder top 16 inside the middle cylinder 10 is provided with a slidable position regulating plate 17 having a spring 17a. (3rd
The figure shows a position regulating body 17' made of a sphere. ) Combustion air is supplied from a blower mechanism 21 consisting of a motor 18, a fan 19, and a fan case 20 to the middle cylinder 10 via a wind box 22. The flow and recirculation amount of combustion gas in the combustion chamber 6 and the internal pressure are controlled by a combustion ring 23. With such a configuration, there is a combustion area a in the upper part of the middle cylinder 10 in the combustion chamber 6, a premix amount *b for forcibly mixing fuel particles and vaporized fuel between the middle cylinder 10 and the auxiliary combustion cylinder 11, A recirculation region C is formed between the combustion chamber 6 and the auxiliary combustion tube 11.

In the above configuration, first, the motor 18 is energized and the blower mechanism 2
1 is activated, combustion air flows into the middle cylinder 10 via the wind box 22, and most of the air is premixed by the position regulating plate 17 through the middle and lower nozzle holes 15 on the middle cylinder 10. It is ejected into the region and forms a strong swirling flow, and most of it becomes an upward flow and flows out of the combustion chamber 6, but a portion passes through the recirculation region C and flows into the premixing region again. After a certain time delay in the operation of the blower (seedling 21), the ignition electrode 4 is energized and a spark is generated.Then, the liquid fuel pressurized to a constant pressure by the operation of the fuel pump 2 is delivered to the combustion chamber 6 from the spiral injection valve 3. The fuel is diffused and mixed in the swirling flow formed in the combustion chamber 6 by air ejected from the middle and lower nozzle holes 15 on the middle cylinder 10, and reaches a constant mixing ratio and a constant temperature. After that, ignition occurs and combustion occurs.The flame in this transition combustion period is sufficiently supplied with air within the premixing region, and forms a swirling diffusion flame (luminous flame) with high brightness in the middle part above the middle cylinder 10. The vicinity of the flame formation part, the wall bottom part 9' of the combustion chamber 6, and the combustion chamber bottom part 9 are heated by radiation and high-temperature flame until they reach a certain temperature after ignition, and the attached unburned matter (tar compound) is forcibly removed. It decomposes and vaporizes and disappears.Meanwhile, after ignition, as the temperature inside the combustion chamber 6 rises, heat is conducted to the spring 17a provided in the middle cylinder 10, and the spring constant changes (to the steady state spring constant k-). ';k) changes to k'). As a result, the position regulating plate 17 moves upward due to the pressure of the supplied combustion air, and the combustion air is also supplied from the upper part of the middle cylinder 10. The vaporization of the fuel within the premixing region is also promoted, and as a result, the concentration of the premixture exceeds the flammable limit.
The flame gradually moves to the upper part of the middle cylinder 10 and at the same time takes in air from the upper part to change to non-bright flame combustion, and performs multi-stage combustion to form a large number of single hole flames on the middle cylinder 10. Steady combustion is performed in this way.

As explained above, according to this embodiment, by providing the slidable position regulating plate 17 having the spring 17a inside the middle cylinder 10, (1) generation and adhesion of soot during the diffusion flame in the transition combustion period; can be suppressed.

(2) The tar-like unburned matter that is generated during steady combustion and accumulates can be burnt out by the self-cleaning action of repeated ignition operations.

Effects of the Invention According to the liquid fuel combustion device of the present invention, by providing the nozzle position regulating plate in the middle cylinder, a self-cleaning action by a bright flame can be performed every time the ignition operation is repeated, and at the same time, the generation and adhesion of soot can be prevented. can be suppressed, and the combustion characteristics (
It is possible to permanently maintain exhaust gases (including Co, HC, odor, etc.) during ignition and extinguishing.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view showing a conventional liquid fuel combustion device;
The figure is a longitudinal sectional view showing one embodiment of the liquid fuel combustion device of the present invention, and FIGS. 3a and 3b are partially enlarged views showing one embodiment of the middle cylinder and its interior. 3... Volute injection valve (liquid fuel atomization means)
, 6... Combustion chamber, 9... Bottom of combustion chamber,
1o...Curved middle tube, 11...Auxiliary combustion tube, 15...
... Air outlet, 17... Curved position guide IJ plate, 17
′...Position regulator.

Claims (2)

[Claims] (1) A bottomed cylindrical combustion chamber in which I/iAi is closed;
The combustion chamber is provided with a middle cylinder erected approximately at the center of the bottom of the combustion chamber and having a large number of air injection holes on its side wall, and an auxiliary combustion cylinder erected approximately concentrically around the outer periphery of the middle cylinder; A liquid fuel combustion device, wherein a means for atomizing liquid fuel is exposed, and means for varying an air ejection position is provided in the middle cylinder. (2) The liquid fuel combustion device according to claim 1, wherein the air jetting position in the middle cylinder is movable after a certain period of time or after a certain temperature is detected.