JPS6138316A - Liquid fuel combustion device - Google Patents

Abstract

PURPOSE:To contrive to perform a stablized gasification combustion based on the recirculation system by providing a governing device for reducing amount of air discharging from the air feeding hole of the primary air. CONSTITUTION:Surroundings of a fuel nozzle 12 and an ignition plug 13 are covered with a covering 18 characterized as a governing device, having an air throttling hole 19 to reduce the volume of an air discharged from the feeding hole for primary air 11. By this device, the combustion flame becomes the dispersing gasified and retained flame by the secondary air, therefore, its performance is excellent in keeping flame, a stablized combustion under a low noise may be realized, the flame thereof becomes short and it is useable for a small type furnace. Bisides, the flame roll-in effect against the fuel nozzle, the ignition plug, and around adjacent places are eliminated, causing release from dirty condition and no needs for cleaning. Further, no heating up to the inner tube takes place, so the burner tube may be miniaturized. ON the other hand, vaporising without use of a heater and gasified combustion under blue flame for almost all flames, which are resulted in a higher thermal efficiency and a lower generation of smoke.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a liquid fuel combustion device used in water heaters, hot water boilers, hot air heaters, etc. for the purpose of supplying hot water or space heating.

(b) Prior art The applicant has proposed a liquid fuel combustion device of this type as shown in FIG. 5 (Japanese Patent Application No. 75439/1982). This one has a fuel nozzle (2) facing the combustion chamber (11),
A primary air supply hole (3) that blows out primary air for combustion into the combustion chamber (1) from around this nozzle (2), and a nozzle (2).
) is installed coaxially with the nozzle in front of the rectifying tube (4) for recirculating combustion gas in the combustion zone to the vicinity of the nozzle;
A large number of secondary air supply holes are arranged around the combustion chamber in front of the straightening tube (4) and eject secondary air for combustion in a direction perpendicular to the axes of the nozzle (2) and the straightening tube (4). 5
), and a large number of through holes (
6) Or an annular flame holding plate with a notch (equipped with a force).

The liquid fuel combustion device described above blows primary air with a high flow rate into the straightening tube (4) from the primary air supply hole (3), creating a negative pressure between the straightening tube (4) and the bottom of the combustion chamber (1). A part of the combustion gas in the combustion zone is returned to the straightening tube (4), and a part of the combustion gas in the combustion zone is returned to the straightening tube (4).
) by reducing the oxygen concentration in the nozzle (2).
Fuel such as kerosene sprayed from the tank is vaporized and gasified and combusted without a heater.

In addition, secondary air from the surroundings collides perpendicularly with the mixed gas flow of vaporized fuel and primary air that has passed through the straightening tube (4), and this collision promotes the mixing of vaporized fuel and air. At the same time, the combustion flame can be stabilized by utilizing the vortex generated above the flame stabilizing plate (7).

However, since the combustion gas is recirculated using primary air having a high flow rate, there are the following problems.

■ Because the flow velocity near the nozzle (2) is high, the combustion flame is easily blown out, resulting in poor ignition characteristics. Furthermore, when the flow rate is slowed down, it is difficult to form a recirculation flow.

■ A vortex is generated when the primary air passes through the primary air supply hole (3). A portion of the fuel sprayed from the nozzle (2) gets caught up in this vortex and burns before the fuel is vaporized, so accounts payable are likely to occur near the nozzle.

■ The flow rate of the secondary air supplied from the secondary air supply hole (5) is slow, and the combustion flame cannot be held stable by the vortex flow caused by the secondary air, so a separate flame holding plate (force) is required.

■ The direction of the primary air must be parallel to the axis of the nozzle (2) in order to form a good recirculation flow and maintain uniformity of the combustion flame. For this reason, it is necessary to prevent the combustion air sent from the blower from swirling, which places restrictions on the installation of the blower.

■ Variation in fuel spray angle of nozzle (2) (usually ±5
The recirculation gas amount varies depending on the tolerance (°).

That is, the larger the spray angle, the larger the amount of recirculation, and the smaller the spray angle, the smaller the amount of recirculation.

If the amount of recirculation deviates from the appropriate value and becomes excessive, combustion flames will be involved and the vicinity of the nozzle will become high temperature, causing problems with the heat resistance of the nozzle and parts in the vicinity of the nozzle. Conversely, if the amount of recirculation becomes too small, the temperature near the nozzle will not reach the temperature required for vaporizing the fuel, making it difficult to perform gasification and combustion.

(c) Problems to be Solved by the Invention The object of the present invention is to solve the problems of the prior art described above and to perform stable gasification combustion using a recirculation system.

2) Means for Solving the Problems □According to the present invention, the above problem is solved by disposing a bottomed inner cylinder at a distance within the outer cylinder to which combustion air is supplied. A fuel nozzle and a spark plug are installed in the primary air supply hole provided in the bottom plate, and a rectifying cylinder coaxial with the nozzle is installed in the inner cylinder in front of the nozzle. In addition to drilling a supply hole, a guide member is attached to deflect the secondary air discharged from the secondary air supply hole toward the straightening cylinder, and an adjustment device is provided to narrow down the amount of air discharged from the primary air supply hole to a small amount. This can be solved by being prepared.

The amount of primary air is determined by the spark discharge from the spark plug being carried away by the wind and reaching the spray range of the fuel nozzle.
No vortex is generated on the outlet side of the air supply hole, and immediately after the start of combustion, there is an oxygen deficiency in the vicinity of the 7' nozzle in the cylinder (tM)-? rmC kerosene is limited to a small amount (the amount of oil is 1.2 to 6% by volume), and preferably the entire amount is It is recommended that the amount be 10% or less of the amount of combustion air.

((e) Operation When fuel is sprayed from the fuel nozzle and the ignition plug is activated, the spark discharge from the ignition plug is carried away by the primary air flow,
reaching the spray range of the fuel nozzle.

Further, since the amount of primary air is narrowed down to a small amount and the combustion flame does not blow out, ignition is performed satisfactorily. When combustion occurs, the area near the nozzle in the inner cylinder immediately becomes deficient in oxygen, and the combustion flame advances toward the front of the rectifier cylinder in the inner cylinder. This is caused by the vortex flow of secondary air discharged at high speed from numerous secondary air supply holes.
It becomes flame resistant. In addition, the secondary air is deflected toward the straightening tube by the guide member, and a part of the combustion gas is drawn in to form a recirculation flow that circulates through the straightening tube, so the fuel sprayed from the fuel nozzle is supplied to the secondary air. Vaporization is accelerated before reaching the pores. In this way, flame-stabilized distributed gasification combustion is performed with the secondary air discharged from the many secondary air supply holes. Furthermore, since the flow velocity of the primary air is slow, it is possible to prevent vortices from occurring near the nozzle, and it is possible to prevent accounts payable from occurring in this area. Furthermore, the secondary air may or may not be a swirling flow, and there are no restrictions on the attachment of the blower. Furthermore, since the guide member is heated by the combustion flame, fuel that has not been vaporized during recirculation can be applied to the guide member and vaporized, making it possible to avoid being affected by variations in the spray angle of the fuel nozzle. .

(f) Example Hereinafter, embodiments of the present invention shown in the drawings will be described.

FIG. 1 shows a liquid fuel combustion apparatus according to an embodiment of the present invention. In Figure 1, (8) is an outer cylinder to which combustion air is supplied from a blower (not shown), and (9) is an interval within the outer cylinder (8) that becomes a secondary air passage (10). The bottomed inner cylinder is connected to the outer cylinder (8) at its tip, and the round is the primary air supply hole provided in the bottom plate (9a) of the inner cylinder (9), and (13) is the primary air supply hole αB
The fuel nozzle and spark plug were installed on the side, the rectifier cylinder was installed coaxially with the (1 side nozzle a) and the nozzle 02 in the front inner cylinder (9), α■ is the inner cylinder (9) in front of the rectifier cylinder α. ), an annular part (16a) that is attached to the tip opening of the machiya inner cylinder (9) and closes the opening periphery; A guide member (17) consisting of a cylindrical part (16b) whose peripheral edge is bent inward is disposed between the rectifying cylinder (141) and the guide member (16) in the inner cylinder (9), This is a cover that serves as an adjustment device that covers the rectifier plate that assists the function of the guide member (16), the fuel nozzle (1), and the ignition plug α□□□. Air supply hole 01
) has an air hole α9 that restricts the amount of air discharged to 10% or less of the total amount of combustion air.

The secondary air supply holes αυ have a diameter of 2 to 2.5 beads, and are arranged in several rows (5 rows in this example) around the entire circumference at intervals of several hundred holes in total. There are several.

Next, the operation of the above-described embodiment apparatus will be explained with reference to FIGS. 2 to 4. First, fuel is sprayed from the fuel nozzle QJ (70 μmm in particle size), and the spark plug 03) is activated to start combustion. At this time, there is sufficient fresh air near the nozzle in the inner cylinder (9). Further, the spark discharge from the spark plug α3) is carried out by the primary air flow shown by arrow A in FIG. 2, and comes into contact with the fuel sprayed from the nozzle (12). Moreover, since the flow velocity of this primary air flow is low, ignition is reliably performed and a combustion flame is formed in the vicinity of the nozzle in the inner cylinder (9).

When combustion starts, since the amount of air discharged from the primary air supply hole α° C. is small, the oxygen concentration in the inner cylinder (9) near the nozzle rapidly decreases, resulting in an oxygen-deficient state. Therefore, the combustion flame advances toward the front of the straightening cylinder inside the inner cylinder (9). The flame is stabilized by the eddy flow of high-speed secondary air discharged from the numerous secondary air supply holes (151 (arrow opening in Figure 3). Also, the secondary air is rectified by the guide member Q6). It is deflected by the plate (17) in the direction of the straightening tube I, forming a recirculating flow shown by the arrow in FIG. This recirculation flow entrains a part of the combustion gas, so oxygen depletion near the nozzle progresses, and the nozzle (I
By the time the fuel sprayed from the secondary air supply hole (151) reaches the secondary air supply hole (151), it is vaporized and becomes fine particles of about 5 μm. ) is heated to about 800°C by the combustion flame, so it hits the current plate (17) and evaporates.In this way, after the start of combustion, it quickly shifts to gasification combustion, and the combustion flame As shown in Fig. 4, a dispersed gasification flame (blue flame) is maintained in the vicinity of several hundred secondary air supply holes α.

According to this embodiment, since the combustion flame becomes a dispersed gasification flame,
Stable gasification combustion is achieved with less flame fluctuation and lower combustion noise. In addition, since the flow velocity of the primary air is slow,
The combustion flame does not blow out at the time of ignition, improving the ignition characteristics, and the combustion flame does not get caught in the vicinity of the nozzle (12+), which prevents accounts payable from occurring in this area. Flame stabilization can be achieved by the vortex flow of secondary air discharged from the cylinder (9), eliminating the need for a flame stabilization plate.Also, the secondary air discharged into the cylinder (9) from the secondary air supply hole α0 has a swirling flow. The secondary airflow does not have to be a straightening tube I, and the blower can be attached freely.Furthermore, the guide member Q6) and the straightening plate 07) direct the secondary airflow
It is possible to vaporize the fuel sprayed from the nozzle α2 by deflecting it in the direction and forming a recirculation flow, and it is also possible to vaporize the fuel directly with the baffle plate αη, which reduces the variation in the spray angle of the fuel nozzle 02. The impact will also be less.

(g) Effects of the invention Since this invention is configured as described above, it has the following effects.

i) Since the combustion flame becomes a dispersed gasification flame that is stabilized by secondary air, stable combustion with excellent flame stability and low noise can be realized. can also be applied.

i) Since there is no flame entrainment near the fuel nozzle and spark plug, most of the dirt is removed and cleaning is not necessary.

iii) Since the inner cylinder is not heated, the burner cylinder can be made smaller.

iv) Since vaporization is performed without using a heater, and gasification combustion is performed in which the entire flame is almost blue, it is economical, has high thermal efficiency, and generates little soot and smoke.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the device of the present invention, FIG. 2 is an explanatory diagram showing the flow of combustion air, and FIG.
FIG. 4 is an explanatory diagram showing the formation of a vortex flow by air, FIG. 4 is an explanatory diagram also showing the combustion state, and FIG. 5 is a sectional view showing an example of a conventional device. (8)...Outer cylinder, (9)...Inner cylinder, (9a).
...Bottom plate, (11)...Primary air supply hole, (121
...Fuel nozzle, a■...Spark plug, (14
)-- Rectifier tube, 051... Secondary air supply hole, a
e... Guide member, (17)... Current plate (guide member), Qa... Cover (adjusting device). Applicant: Sanyo Electric Co., Ltd. and 1 other agent: Patent attorney: Makoto Sano, 5th WJ

Claims (2)

[Claims] (1) A bottomed inner cylinder is placed at a distance within the outer cylinder to which combustion air is supplied, and a fuel nozzle and spark plug are installed in the primary air supply hole provided in the bottom plate of this inner cylinder. A rectifying cylinder coaxial with the nozzle is arranged in the inner cylinder in front of the nozzle, and a large number of secondary air supply holes are bored in the inner cylinder in front of the rectifying cylinder, and air is discharged from the secondary air supply hole. 1. A liquid fuel combustion device comprising: a guide member for deflecting secondary air toward a rectifying tube; and an adjusting device for reducing the amount of air discharged from the primary air supply hole to a small amount. (2) Claim 1, characterized in that the amount of air discharged from the primary air supply hole is 10% or less of the total amount of combustion air.
The liquid fuel combustion device described in .