JPH031568B2 - - Google Patents

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 configuration and problems thereof Conventionally, this type of combustion apparatus has been configured as shown in FIG. That is, a large number of air jet holes 1
A middle cylinder 9 having a side wall 4 and an auxiliary combustion cylinder 10 are arranged approximately concentrically, and liquid fuel atomization means are respectively arranged upright and adjacent to the combustion chamber 6. Fuel is supplied from the atomization means 3, and combustion air is supplied from the blower mechanism 2.
0, the air is continuously supplied into the combustion chamber 6 from each air injection hole 14 on the middle cylinder 9 via an air blowing path 21. The group of fuel particles supplied by the atomization means 3 flows into the premixing region b from the spray nozzle 12 on the auxiliary combustion cylinder 10, mixes with the air jetted from the middle cylinder 9, and initially performs diffusive 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, constantly exchanging heat (cooling), and the rise in temperature to a predetermined temperature is considerably suppressed. On the other hand, the moment of the sprayed/atomized fuel particles is considerably larger than that of the air in the combustion chamber 6 and reaches the middle cylinder 9 and collides with it.
Some of it re-liquefies and flows down to the bottom 8 of the combustion chamber.

As a result, a portion of the fuel that has re-liquefied and flowed down is vaporized due to the temperature within the combustion chamber 6, but remains at the bottom 8 of the combustion chamber and forms a pool. Furthermore, when igniting and extinguishing the fire, odors were generated and the mixture ratio of air and fuel was uneven, resulting in deterioration of exhaust gas. This phenomenon became more serious as the combustion device was made smaller and shifted to the high-load combustion side.

Purpose of the Invention The present invention is intended to solve the above-mentioned problems, and aims to improve combustion characteristics by suppressing fuel pooling at the bottom of the combustion chamber due to re-liquefaction of fuel on the inner cylinder wall surface and flowing down, and promoting smooth evaporation. purpose.

Structure of the Invention In order to achieve this object, the present invention provides a connecting member for connecting and fixing the middle cylinder through a mounting flange and connecting it to the air supply blowing pipe below and inside the lowermost stage air jet hole of the middle cylinder. It was established.

With this configuration, it is possible to suppress heat exchange in the middle cylinder by forming a double pipe with a heat-insulating structure at the bottom of the middle cylinder and minimizing the contact surface with combustion air. . As a result, even if the recirculating gas comes into contact with the middle cylinder, cooling is suppressed, reliquefaction phenomenon is suppressed, and combustion is maintained at a predetermined mixing ratio.

DESCRIPTION OF EMBODIMENTS Hereinafter, implementation instructions of the present invention will be explained based on FIGS. 2 and 3.

In the figure, 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, and the spiral injection valve 3 and an ignition electrode 4 are connected to each other via an oil pipe 1. is included in the support tube 5 and incorporated into the combustion chamber 6. The main body is formed of inner and outer combustion tubes 7, 7', and at the same time the combustion chamber 6
It consists of Further, a middle cylinder 9 is provided at approximately the center of the bottom 8 of the combustion chamber 6, and an auxiliary combustion cylinder 10 is provided upright on the outer periphery of the middle cylinder 9. The ends of the spiral injection valve 3 and the ignition electrode 4 are provided directly in the combustion chamber 6 through the wall opening 11 of the combustion chamber 6, so that fuel spray particles do not collide with the auxiliary combustion tube 10. A sufficiently large spray hole 12 is provided as shown in FIG.
A large number of circulation holes 13 are provided on the same circumference near the bottom 8 of the combustion chamber. Further, around the side wall of the middle cylinder 9, a large number of air jet holes 14 are arranged in a tangential direction.
Alternatively, they are provided so as to move upward from the bottom and gradually from the tangential direction to the perpendicular direction. With such a configuration, there is a combustion area a in the upper part of the middle cylinder 9 in the combustion chamber 6, a premixing area b where fuel particles and vaporized fuel are forcibly mixed between the middle cylinder 9 and the auxiliary combustion cylinder 10, A recirculation region c is formed between the combustion chamber 6 and the auxiliary combustion tube 10. Inside the middle cylinder 9, a joint pipe 16 (joint member) having a mounting flange 15 is connected approximately concentrically to the vicinity of the lowest stage of the air jet hole 14 to form a double pipe. Combustion air is supplied to the middle cylinder 9 from a blower mechanism 20 composed of a motor 17, a fan 18, and a fan case 19 via a blower pipe 21.

In the above configuration, when the motor 17 is first energized and the blower mechanism 20 is activated, combustion air is supplied to the blower pipe 21.
The air flows into the middle cylinder 9 through the air, and is ejected from each air jet hole 14 on the middle cylinder 9 to the combustion area a and the premixing area b, forming a swirling flow. Further, each type of air at this time is supplied at a fixed ratio, and some of the air flows through the recirculation area c to the circulation hole 13, and some air flows into the premixing area b again from the spray hole 12.
After a certain time delay in the operation of the blower mechanism 20, the ignition electrode 4 is energized and a spark is generated. Thereafter, pressurized liquid fuel is sprayed into the combustion chamber 6 from the spiral injection valve 3 by the operation of the fuel pump 2 . Each spout 1
The fuel is diffused and mixed in the swirling flow formed in the combustion chamber 6 by the air ejected from the combustion chamber 6, and after reaching a certain mixing ratio and a certain temperature, the fuel is ignited and combusted. Initially, it exhibits diffusion combustion, and then the heat of combustion causes multi-stage vaporization premix combustion using multiple single-hole flames. The temperature of the atmosphere and each component increases due to the flame in the combustion chamber 6 and the convection of recirculated gas due to combustion. The lower part of the middle cylinder 9 is a double pipe and is insulated and the contact surface with the combustion air is minimized, so that the temperature drop due to cooling during heat exchange is suppressed as much as possible. Therefore, the group of fuel particles that collide with a part of the middle cylinder 9 are heated on the middle cylinder 9 and complete vaporization, or they vaporize and evaporate as they flow down as a liquid stream and reach the bottom 8 of the combustion chamber and form a pool. Doing so is strictly discouraged.

Next, another embodiment of the present invention will be described with reference to FIG. In this embodiment, the mounting flange 15 in the above-mentioned embodiment is only inclined to provide a slope, and other essential structural functions are the same as in the above-mentioned embodiment. In addition, although the operation and the like are exactly the same, by inclining the mounting flange 15 and providing a slope, the pressure loss on the path of the air supplied from the ventilation mechanism 20 is suppressed as much as possible. The swirling air is effectively ejected and supplied into the combustion chamber 6.

Effects of the Invention As explained above, according to the liquid fuel combustion device of the present invention, the lowermost air jetting part of the middle cylinder is connected to the middle cylinder via the mounting flange inside, and the air supply blow pipe is connected to the middle cylinder through the mounting flange. By providing a joining member for connection, it is possible to suppress the temperature drop in the middle cylinder, suppress the pooling of colliding fuel particles at the bottom of the combustion chamber, and reduce combustion exhaust gas during steady combustion and during extinguishing, especially Characteristics such as odor, HC, and CO can be improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a conventional liquid fuel combustion device, FIG. 2 is a vertical sectional view showing an embodiment of the liquid fuel combustion device of the present invention, and FIG. 3 is a middle cylinder and combustion chamber in FIG. 2. FIG. 4 is a partially enlarged view of the center cylinder and the vicinity of the bottom of the combustion chamber showing another embodiment. 3... Spiral injection valve (liquid fuel atomization means), 6... Combustion chamber, 7, 7'... Combustion cylinder, 9...
Middle cylinder, 10... auxiliary combustion cylinder, 14... air nozzle, 1
5...Mounting flange, 16...Joining pipe (joining member).

Claims (1)

[Scope of Claims] 1 A bottomed cylindrical combustion chamber is constituted by a middle cylinder, an auxiliary combustion cylinder, and a combustion cylinder each having a large number of air injection holes arranged from the center on substantially concentric circles, A liquid atomization means is made to face the combustion chamber through an opening provided in the chamber, and is connected to the middle cylinder via a mounting flange at the bottom of the lowest air jet hole of the middle cylinder and inside, for air supply. A liquid fuel combustion device provided with a connecting member for connecting to a blower pipe. 2. The liquid fuel combustion device according to claim 1, wherein the connection angle between the joining member and the mounting flange is inclined at 90 degrees or more.