JPS643943Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a liquid fuel combustion device for use in oil water heaters and the like equipped with a recirculation combustion burner.

Hitherto, various structures have been known for this type of liquid fuel combustion device, and the applicant of the present application has also applied for the structure shown in FIG. 4 in Japanese Patent Application No. 174975/1982.

To explain the one in Fig. 4, there is a fuel spray nozzle 2 inserted into the combustion chamber 1, and a fuel spray nozzle that surrounds the nozzle and is provided coaxially with the fuel spray nozzle so that the sprayed fuel jetted from the fuel spray nozzle collides with the inner peripheral surface. The burner cone includes a burner cone 4, a rectifying plate 5 provided at the front end opening of the burner cone, and an air outlet 6 provided coaxially with the nozzle surrounding the nozzle. Made of ceramic, the front half is expanded forward at a slightly narrower angle than the spray angle of the fuel spray nozzle.
The rear half is formed into a cylindrical shape, and a combustion gas suction section 3 is appropriately opened in the circumferential direction thereof, and the baffle plate is formed into a conical or hemispherical shape with a water-absorbing porous ceramic having an open substantially bottom surface. A number of small holes 8 are provided at appropriate locations, and the convex surface is directed toward the inside of the burner cone, with a constriction part 9 at an appropriate interval between the convex surface and the burner cone, and is arranged coaxially with the burner cone. Two methods are used for vaporization: the vaporization of the atomized fuel by suction of combustion gas, and the vaporization of fuel droplets by the water absorption action of the porous ceramic surface. However, at the time of initial ignition, that is, when the combustion chamber is cold, Furthermore, if the burner cone serving as the vaporizing surface is ignited while it is still cold, there remains the problem that it takes some time to obtain a stable blue flame.

The reason for this is that the entire burner cone is exposed inside the combustion chamber, and the combustion gas suction section opens directly into the combustion chamber, so the combustion gas suction section will suck in combustion gas from the entire area of the combustion chamber. However, until the entire area of the combustion chamber reaches a high temperature, it is not possible to suck in combustion gas hot enough to vaporize the fuel smoothly, and it takes some time for the temperature of the burner cone to rise due to the sucked combustion gas. This is because they need it.

Therefore, the purpose of the present invention is to eliminate the above-mentioned drawbacks and to make it possible to obtain a stable blue flame in a short period of time.To this end, the technical problems that the present invention attempts to solve are mainly related to the burner. The method is to suck only the high-temperature combustion gas near the cone exit through a short path along the outer circumferential surface of the burner cone.

The basic structure of the present invention to achieve the above technical problem is that a cylindrical burner mounting flange pipe that opens into the combustion chamber is provided on the peripheral wall of the combustion chamber, and a burner cone is installed inside the flange pipe. Most of the fuel gas suction section is located within the flange pipe.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, reference numeral 1 denotes a combustion chamber, which is formed into a cylindrical shape and has a heat exchanger 10 installed along its peripheral wall, and flange pipes 7 for attaching burners at required locations on the peripheral wall.

The burner mounting flange pipe 7 is provided in a direction perpendicular to the axial direction of the combustion chamber 1, passing through the peripheral wall of the combustion chamber 1 and the heat exchanger 10 along it, so that the inner end slightly protrudes into the combustion chamber 1. It is formed into a cylindrical shape with an open inner end and a closed outer end with a closing plate 11, and a burner A is installed inside.

The burner A includes a fuel spray nozzle 2, a burner cone 4 provided surrounding the fuel spray area of the fuel spray nozzle 2, a baffle plate 5 provided at the outlet of the burner cone 4, and a burner cone 4 provided surrounding the fuel spray nozzle 2. It is equipped with an air outlet 6.

The air outlet 6 is provided coaxially with the burner mounting flange pipe 7 at a rearward midway point of the flange pipe 7, facing the inside of the combustion chamber 1 from within the flange pipe 7. The rear end of the flange pipe 7 is connected to the blower 1 through an opening 12 provided in a closing plate 11 at the rear end of the flange pipe 7.
The nozzle 6 is connected to the air duct 14 of the nozzle 3 and has a straight cylindrical air outlet portion 6 a at its tip which opens in a direction perpendicular to the axial direction of the combustion chamber 1 .

Further, the air outlet 6 extends through the oil pipe 15 at its axial center.

The oil supply pipe 15 connects to an oil supply source 16 outside the combustion chamber 1.
In addition, an electromagnetic pump 17 is provided in the middle.

The fuel spray nozzle 2 has a conventionally well-known structure, is formed so that the spray angle is, for example, approximately 60 degrees, and is connected to the tip of the oil feed pipe 15 so as to face the center of the burner cone 4, which will be described later. .

A pair of igniters 18 are disposed close to the fuel spray nozzle 2 so as not to obstruct the flow of air from the air outlet 6.

The burner cone 4 is made of water-absorbing porous ceramic, and has a straight cylindrical rear half and a conical shape that expands forward at an angle slightly narrower than the spray angle of the fuel spray nozzle 2. A flange pipe for attaching a burner to the side wall of the combustion chamber 1 is installed coaxially with the fuel spray nozzle 2 and the air outlet 6 so that the sprayed fuel sprayed from the spray nozzle 2 collides with the inner peripheral surface of the expanded portion 4a. 7
Attach to.

The burner cone 4 has a distal end slightly protruding from the front end of the flange pipe 7, and most of it is accommodated within the flange pipe 7, and a combustion gas suction section is provided at the rear end of the cylindrical portion 4b along its circumferential direction. 3 is opened as appropriate so that its opening area is the required area to achieve suction of an appropriate amount of combustion gas, and a rectifier plate 5 is provided at the front end opening, that is, the outlet.

In the illustrated embodiment, the combustion gas suction section 3 has a structure in which the cylindrical section 4b of the burner cone 4 is formed long and its rear end is directly fixed to the closing plate 11 at the rear end of the flange pipe 7. Although the burner cone 4 is formed on the circumferential surface of the cylindrical part 4b, the cylindrical part 4b is formed short and is held in the flange pipe 7 using a suitable holding member such as a stay, and the rear end and the flange pipe 7 are connected to each other. It may also be formed by providing a gap with the closing plate 11.

The current plate 5 is made of water-absorbing porous ceramic and is formed integrally with the burner cone 4 into the shape shown in the figure.

That is, the current plate 5 is formed into a hollow conical or hemispherical shape with an open bottom, and is inserted into the outlet of the burner cone 4 with its convex surface facing inward to the burner cone 4 and connected to the burner cone 4. It is provided coaxially and communicates with the burner cone 4 via a connecting piece 19 at appropriate locations on the circumferential surface.

The baffle plate 5 has a forward opening angle slightly larger than the opening angle of the expanded portion 4a of the burner cone 4, and its front end slightly protrudes from the outlet end of the burner cone 4. and the baffle plate 5 form a constriction part 9 at the outlet of the burner cone 4 with an appropriate spacing that does not inhibit suction of combustion gas and is effective for promoting mixing of vaporized fuel and air.

Further, an appropriate number of small holes 8 are bored in the current plate 5.

Note that this current plate 5 does not necessarily have to be molded integrally with the burner cone 4 as described above, but can be molded separately from the burner cone 4 and fixed to the burner cone 4 or flange pipe 7 using a suitable mounting member. You may also do so. Furthermore, the current plate 5 can also be made of a metal with excellent heat resistance, such as stainless steel.

Thus, such a burner is sprayed by blowing out air sent from the blower 13 from the air outlet 6 and spraying liquid fuel sent from the fuel supply source via the external electromagnetic pump from the fuel spray nozzle 2. Fuel and air are mixed and ignited inside the burner cone 4 by discharge from the igniter 18, resulting in yellow flame combustion.

On the other hand, the air is blown out from the tip of the air outlet 6, causing a suction effect and sucking the surrounding air.

As a result, the burner cone 4 is
The combustion chamber 1 passes through the throttle part 9 between the
Furthermore, a circulation flow a is generated from inside the combustion chamber 1 through the combustion gas suction part 3 to the inside of the burner cone 4, but as mentioned above, the burner cone 4 is mostly is accommodated in the flange pipe 7, and the combustion gas suction part 3 is located in the flange pipe 7, so that the circulation flow a
flows outside the burner cone 4 through a path from the outlet of the burner cone 4 to the combustion gas suction port 3 through a narrow gap 20 between the outer periphery of the burner cone 4 and the flange pipe 7.

Therefore, even during the initial combustion, high-temperature combustion gas is sucked into the burner cone 4, and the sucked high-temperature combustion gas flows between the burner cone 4 and the flange pipe 7, so that the burner cone 4 is also heated from the outside, and burner cone 4
temperature rises rapidly.

As described above, after ignition, hot combustion gas is sucked into the burner cone 4 by the circulation action, and the atomized fuel is instantaneously vaporized by the heat. The vaporized fuel is promoted to mix with combustion air in the constriction section 9 between the outlet section of the cone 4 and the baffle plate 5.

Then, the yellow flame inside the burner cone 4 moves to the downstream part of the baffle plate 5 at the same time as it sucks in the combustion gas,
At this point, the mixture ignites and becomes a blue flame.

At this time, if the diameter of the air outlet portion 6a of the air outlet 6 is too small, the air blowing speed will become too high.
It collides with the current plate 5 and moves backward, applying back pressure.
The suction of combustion gas becomes poor, and conversely, if it is too large, the air flow velocity slows down and the suction of combustion gas becomes poor.

Furthermore, if the length of the blow-off port 6a is too short, the blowing air will not flow in the axial direction and the spark of the igniter 18 will not be able to flow into the fuel spray area, resulting in ignition failure.

Therefore, it is desirable that the relationship between the diameter and length of the air outlet portion 6a of the air outlet 6 is such that the length is about 1/2 or more of the diameter.

Further, the diameter of the blower outlet portion 6a and the diameter of the straight cylindrical portion 4b of the burner cone 4 are also closely related, and the diameters of both are close to each other. For example, if the diameter of the cylindrical portion 4b of the cone 4 becomes small, the combustion gas and air that are sucked will mix in the front half of the cone 4, causing a flame to start inside the cone 4.

Therefore, the diameter of the cylindrical portion 4b of the burner cone 4 needs to be larger to some extent than the diameter of the air outlet portion 6a of the air outlet 6.

That is, as a result, the air flows in the center and the combustion gas flows in the outside, and the two mix for the first time at the baffle plate 5 and the cone 4 exit constriction part 9, and the cone 4
A flame is formed at the outlet.

On the other hand, the oil droplets sprayed from the spray nozzle 2 and not vaporized by the suctioned combustion gas collide with the inner circumferential surface of the burner cone 4, especially the inner circumferential surface of the widened part 4a, but the cone 4 has water-absorbing porous holes. Since it is made of high-quality ceramic, it is once inhaled and retained within the ceramic. Since the cone 4 has a high temperature due to the heat of combustion and the high-temperature combustion gas circulating and flowing along the outside thereof, the inhaled fuel immediately evaporates and vaporizes and flows to the outlet of the cone 4, and the baffle plate 5 The flow is rectified by the small hole 8 and ignited in the downstream part of the rectifying plate 5, that is, in the recess 21 behind the rectifying plate 5.

In addition, in this embodiment, since the current plate 5 is made of porous ceramic that has water absorption properties, it has the same effect as the burner cone 4, so that the unburned particles that hit the current plate are gasified, so that they are more combusted. will get better.

The concave portion 21 behind the baffle plate 5 serves as a retention point for the air current, and the high temperature combustion gas is retained in this portion, and serves as an ignition source for the fuel mixed with the vaporized air released from the outlet of the cone 4. Therefore, blue flame will come out from the small holes 8 made in the current plate 5.

That is, in such a combustion device, high-temperature combustion gas remains in the concave portion behind the baffle plate, which becomes a source of ignition for the fuel mixture gas, and a stable blue flame is formed from the many small holes provided in the baffle plate. In addition, this flame becomes the ignition source, and the unburned gas that did not ignite behind the rectifying plate mixes with the air supplied from the secondary air blowing ring and ignites, forming a stable blue flame from the small holes. .

Therefore, the flame is stable like a gas burner, there is no fluctuation, and the combustion noise is low and quiet.

In addition, since the burner cone is made of water-absorbing porous ceramic, unburned liquid that hits the burner cone is temporarily sucked into the cone and released as steam, and high-temperature combustion gas is sucked in and released. Combustion sprayed from the nozzle is instantly gasified by heat, and the mixture of the gasified fuel and air is promoted by the straightening plate 5 installed at the cone outlet to achieve complete combustion. I can do it.

the result, a Blue flame combustion without red flame.

b. Generation of soot and carbon monoxide can be suppressed.

c) Excess air ratio can be lowered and combustion efficiency can be increased.

d The length of the flame is short and the combustion chamber can be made smaller.

Furthermore, since the vaporization surface of the burner cone has water absorption properties, even if the temperature of the cone itself rises and becomes considerably higher than the boiling point of the fuel, the phenomenon of fuel becoming granular and generating tar etc. does not occur.

It goes without saying that the present invention is not limited to the above-mentioned embodiments, and that many modifications can be made therefrom.

For example, as shown in FIG. 2, a heat exchanger 1 is installed to prevent overheating of the burner mounting flange pipe 7.
It is possible to widen the width of the portion 10' which contacts the flange pipe 7 of 0 so as to cover substantially the entire length of the flange pipe 7.

With such a structure, the heat exchanger 10
Not only can the flange pipe 7 be cooled by the water inside, but the heat transfer surface is expanded, and the efficiency of the heat exchanger 10 can also be improved.

Further, as shown in FIG. 3, it is also possible to provide a flame holding ring 22 having a V-shaped or U-shaped cross section in front of the current plate 5. By providing the flame holding ring 22 in this way, the current plate The unburned fuel that has not ignited in the recess 21 of No. 5 flows along the inner and outer peripheral surfaces of the flame-holding ring 22 without being disturbed, and is ignited in the recess 23 behind the flame-holding ring 22, resulting in combustion. Noise can be reduced and flame stability can also be further improved.

Furthermore, a cut-and-raised piece 2 is provided on the circumferential surface of the flame-holding ring 22.
It is also possible to improve the function of the flame holding ring 22 by providing holes 25 and holes 25, and it is also possible to provide a secondary air blowing ring in place of the flame holding ring 22.

Since the present invention has the above configuration, it has the following advantages.

(1) Most of the burner cone is housed inside the flange pipe for attaching the burner, and the combustion gas suction part is located inside the flange pipe, so at the time of initial ignition, the combustion gas at the outlet of the burner cone is circulated inside the flange pipe. The inside of this flange pipe is smaller than the combustion chamber, and the circulation path is short, so even if the combustion chamber is cold, high-temperature combustion gas can be sucked in. When combustion gas passes through the flange pipe and is sucked from the suction part, the space between the outer surface of the burner cone and the burner cone on the inner surface of the flange pipe is narrow, so the high-temperature combustion gas flows close to the outer surface of the burner cone, As the fuel is rapidly heated from the outside, the atomized fuel is quickly vaporized and a stable blue flame is obtained instantly after ignition.

(2) If the combustion gas suction part of the burner is installed at the same position as the combustion chamber wall or closer to the combustion chamber, the flow of circulating combustion gas will be affected by the shape of the combustion chamber wall, causing unstable combustion. Something happened.

However, by installing the combustion gas suction section inside the burner mounting flange pipe, the flow of circulating combustion gas takes almost a short path only within the burner mounting flange, and is not affected by the shape of the combustion chamber wall. In addition, the flow of circulating combustion gas was rectified in the axial direction of the flange pipe, and the undisturbed circulating gas was sucked into the burner cone, resulting in a more stable blue flame.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a liquid fuel combustion device showing one embodiment of the present invention, FIGS. 2 and 3 are sectional views showing other embodiments of the present invention, and FIG. 1 is a sectional view of a liquid fuel combustion device previously filed as Japanese Patent Application No. 174975/1982. 1... Combustion chamber, 2... Fuel spray nozzle, 3...
Combustion gas suction section, 4... Burner cone, 5...
Current plate, 6... Air outlet, 7... Flange pipe for attaching burner.

Claims (1)

[Scope of utility model registration request] A combustion chamber, a fuel spray nozzle provided facing into the combustion chamber, and a porous ceramic having water absorbing properties are formed to surround the fuel spray area of the nozzle so that the sprayed fuel jetted from the fuel spray nozzle collides with the inner peripheral surface. The burner cone is arranged coaxially with the nozzle and has a combustion gas suction part at the rear, and the front end of the burner cone is formed into a conical or hemispherical shape with an open bottom and a few small holes on the circumference. A cylindrical burner opening into the combustion chamber is provided in the peripheral wall of the combustion chamber, and includes a rectifier plate provided in a forward facing concave state at the opening, and an air outlet provided coaxially with the fuel spray nozzle surrounding the fuel spray nozzle. A liquid fuel combustion device comprising: a mounting flange pipe; most of the burner cone is accommodated within the flange pipe; and a combustion gas suction section is positioned within the flange pipe.