JPS60256716A - Liquid fuel combustion apparatus - Google Patents

Abstract

PURPOSE:To improve characteristic of a combustion apparatus in order to alleviate combustion noise and exhaust gas, by preventing fuel from staying in the bottom of a flame chamber by promoting heightening of the temperature in the bottom, by increasing the recycling rate of hot gas, by providing a flow guide to the inside wall of a flame chamber. CONSTITUTION:The air is injected from a number of injection holes 14, forming a swirl flow in a flame chamber 6. Fuel is diffused and is mixed with the swirling air flow. Mixed gas is ignited and combustion is started when the mixed gas comes to the specified mixture ratio and the specified temperature. Diffusion combustion is taken place at the beginning, accompanied with luminous flames, and multi-staged combustion is taken place afterwards by flames injected from a number of single holes. Part of a group of single hole flames being formed in the upper part of an inner cylinder 9 is led into a recycling zone (c) by a flow guide 15, and hot combustion gas is recycled, flowing into a premixing zone (b) from the inlet opening 13 of a recycling passageway. With such an arrangement, the rise of temperature in the bottom 8 of a flame chamber is quickly promoted, resulting the prevention of fuel from staying in the bottom markedly.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a liquid fuel combustion device used in a heat source device as a small-sized domestic hot water supply/heating device.

Conventional Structure and Problems Conventionally, this type of combustion apparatus has been structured as shown in FIG. That is, a middle cylinder 9 having a large number of air ejection holes 14 on the side wall and an auxiliary combustion cylinder 10 are arranged substantially concentrically, and a liquid fuel atomization means 3 is respectively arranged upright and adjacent to the combustion chamber 6. .

The fuel is continuously supplied into the combustion chamber 6 from the atomization means 3, and the combustion air is continuously supplied to the combustion chamber 6 by a blower mechanism 19 via a blower pipe 19 and from each air jet hole 14 on the middle cylinder 9.

The group of fuel particles supplied by the atomization means 3 is added to the auxiliary combustion tube 1
The air flows into the premixing region from the nozzle port 12 on the top of the cylinder 0, mixes with the air jetted out from the middle cylinder 9, and initially performs diffusion combustion.
Thereafter, high-speed vaporization and mixing of the fuel is promoted by combustion heat, resulting in premixed combustion. However, combustion air circulates inside the middle cylinder 9 and constantly exchanges heat, so that the temperature rises to a predetermined temperature is rather slow and suppressed. On the other hand, the moment of the sprayed fuel particles is considerably larger than that of the airflow in the combustion chamber 6 and reaches the middle cylinder 9 and collides with it, and some of the particles coalesce and flow down to the bottom 8 of the combustion chamber.

As a result, at the beginning of combustion, part of the fuel that has coalesced and flowed down is vaporized by the temperature inside the combustion chamber 6, but most of it accumulates in the bottom 8 of the combustion chamber and forms a pool, gradually promoting vaporization as the temperature rises. In addition, the flame holding area fluctuated due to unevenness in the air/fuel mixture ratio, the exhaust gas deteriorated, and the noise and exhaust gas deteriorated due to the odor during extinguishing. When the combustion equipment was downsized to perform high-load combustion and variable control of the combustion amount, the temperature rise in the middle cylinder and the bottom of the combustion chamber became slow, and this phenomenon was extremely serious.

Purpose of the Invention The present invention solves the above problems, and aims to improve combustion characteristics such as combustion noise and exhaust gas by suppressing the formation of a fuel pool at the bottom of the combustion chamber due to coalescence and flowing down, and promoting smooth evaporation. purpose.

Structure of the Invention In order to achieve this object, the present invention provides a flow guide plate on the wall surface of the combustion chamber of the combustion tube and above the auxiliary combustion tube.

This configuration redirects a portion of the flame that is formed to increase the amount of heat that is recirculated, thereby promoting an increase in temperature at the bottom of the combustion chamber.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in Section 2. This will be explained based on FIG.

In the figure, the fuel tank (not shown) has an oil supply pipe 1.
A fuel pump 2 and an injection valve 3 as an atomization means are connected via the fuel pump 2, and the injection valve 3 and the ignition electrode 4 are included in a support cylinder 5 and incorporated into a combustion chamber 6. The main body is formed of inner and outer combustion boundary parts 7 and 7', which also constitute the combustion chamber 6. Further, a middle cylinder 9 is provided approximately at the center of the bottom 8 of the combustion chamber 6, and an auxiliary combustion cylinder 10 is provided upright on the outer periphery thereof. The tips of the injection valve 3 and the ignition electrode 4 are provided in the combustion chamber 6 through the wall opening 11 of the combustion chamber 6, so that the fuel spray particles do not collide with the auxiliary combustion tube 10. A spray port 12 is provided, and a large number of circulation ports 13 are provided near the bottom 8 of the combustion chamber on the same circumference.
is the provision.

Further, a large number of air jet holes 14 are provided around the side wall of the middle cylinder 9.
is provided in the tangential direction. A flow guide plate 15 is provided on the inner wall of the combustion tube 7 constituting the combustion chamber 6 at a position facing the main flame formed above the auxiliary combustion tube 10. With such a configuration, a combustion area a is formed in the upper part of the middle cylinder 9 in the combustion chamber 6, and a combustion area a is formed between the middle cylinder 9 and the auxiliary combustion cylinder 1.
A premixing region b in which fuel particles and vaporized fuel are forcibly mixed with each other, and a recirculation region C between the combustion chamber 6 and the auxiliary combustion cylinder 10 are formed.

Combustion air is provided by motor 16, fan 17, fan case 1
The air is supplied from an air blowing mechanism 19 composed of air blowing mechanism 8 to the middle cylinder 9 via an air blowing pipe 20.

In the above configuration, when the motor 16 is first energized and the blower mechanism 19 is activated, combustion air flows into the middle cylinder 9 via the blower pipe 20 and from each air jet hole 14 on the middle cylinder 9 into the combustion area. a. It is ejected into the premixing region to form a swirling flow. Further, each type of air at this time is supplied at a fixed ratio, with some of the air flowing through the recirculation area C into the circulation port 13, and some flowing into the premixing area from the spray port 12 again. After a certain time delay in the operation of the blower mechanism 19, the ignition electrode 4 is energized and a spark is generated. Thereafter, pressurized liquid fuel is sprayed into the combustion chamber 6 from the injection valve 3 by the operation of the fuel pump 2 . The fuel is diffused and mixed in the swirling flow formed in the combustion chamber 6 by the air ejected from each ejection hole 14, and after reaching a certain mixing ratio and a certain temperature, it is ignited and combusted. Initially, it exhibits diffuse combustion with a bright flame, and then the heat of combustion causes multi-stage combustion with multiple single-hole flames. A part of the single-hole flame group formed in the upper part of the middle cylinder 9 is guided to the recirculation area C by the flow guide plate 14, and even higher temperature combustion gas is recirculated and sent to the premixing area from the circulation port 13. Inflow. As a result, the temperature of each component, especially the bottom 8 of the combustion chamber, is rapidly increased. Therefore, the fuel that has coalesced and flowed down is quickly vaporized and evaporated at the bottom 8 of the combustion chamber.
Pooling is suppressed as much as possible.

Next, another embodiment of the present invention will be described with reference to FIGS. 4(a) and 4(b). In this embodiment, the proximal portion of the flow guide plate 14 to the wall surface of the combustion tube 7 in the above-mentioned embodiment is only provided with a slope or curvature, and other essential configurations and functions are the same as in the above-mentioned embodiment. . Also, the operations etc. are exactly the same, but
By providing a slope or curvature in the vicinity of the combustion chamber 7 wall surface, stagnation is suppressed or prevented from forming as much as possible, the load such as thermal stress on the flow guide plate 14 is reduced, and high-temperature gas is transferred to the combustion chamber bottom 8. Effectively used for heating.

Furthermore, the flow guide plate is made of heat-resistant material (e.g. ceramic material).
Deformation due to thermal stress, etc. can be further prevented by forming the material.

Details of the Invention As explained above, according to the liquid fuel combustion apparatus of the present invention, by providing a flow guide plate on the wall surface of the combustion chamber, the amount of recirculation of high-temperature gas is increased, and the temperature rise at the bottom of the combustion chamber is quickly suppressed. As a result, fuel pooling is suppressed and combustion characteristics such as combustion noise and exhaust gas can be improved.

[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 FIG. 3 is a partially enlarged view of the vicinity of the combustion chamber in FIG.
FIGS. 4(a) and 4(b) are partially enlarged views of the combustion chamber and the vicinity of the wall surface of the combustion chamber, respectively, showing other embodiments. 3... Injection valve (liquid fuel atomization means), 6...
... Combustion chamber, 7,7'... Combustion cylinder, 9...
...Middle cylinder, 10...Auxiliary combustion cylinder, 11...
Opening portion, 14... Air outlet, 15...
・Flow guide plate.

Claims (4)

[Claims] (1) A cylindrical combustion chamber with a bottom is formed by a middle cylinder having a large number of air ejection holes, an auxiliary combustion cylinder and a combustion cylinder formed approximately concentrically, and fine particles of liquid fuel are released through an opening provided in the combustion chamber. A liquid fuel combustion device, wherein a flow guide plate is provided on a wall surface of the combustion chamber, and a flow guide plate is provided on a wall surface of the combustion chamber. (2) The liquid fuel combustion device according to claim 1, wherein the flow guide plate is provided above the auxiliary combustion cylinder at the position of the main flame forming portion. (3) The liquid fuel combustion device according to claim 1, wherein the flow guide plate near the wall surface of the combustion chamber is provided with a slope or a curvature. (4) The liquid fuel combustion device according to claim 1, wherein the flow guide plate is made of a heat-resistant material.