JPS60245914A - Liquid fuel evaporating type burner - Google Patents

Abstract

PURPOSE:To obtain a complete blue flame by completely separating a nozzle zone, a combustion air zone, a combustion evaporating zone, a mixing zone, a combustion zone, and a high temperature combustion gas circulating zone from each other. CONSTITUTION:The recessed portion at the rear of a smoothening plate 8 becomes a staying point of the air flow. At this point, a high temperature fuel gas stays, and is discharged from an outlet of a cone 6 and is evaporated, and becomes an ignition source to a fuel gas mixed with air. Further, the smoothening plate 8 is made of porous ceramics having a water absorptive property similar to the burner cone 6, and functions as a fuel evaporating surface similar to the burner cone 6, in addition to the function of smoothening the air flow and the that of an ignition source. As a result, a blue flame rises up from small holes formed in the smoothening plate 8, and it is possible to perform the complete combustion and to improve the combustion efficiency.

Description

Detailed Description of the Invention (Field of Industrial Application) This Hatsuro is a gun-type liquid fuel vaporizing burner used in home water heater boilers, etc., especially in the output range of 23.
000 to 57.0001ocal burner.

(Prior Art) The combustion of kerosene is roughly divided into two types, gastritis and gastritis, depending on its mode. A premixed flame containing sufficient oxygen causes gastritis, and a diffusion flame causes gastritis (luminous flame). It is estimated that the combustion process is similar to the flowchart shown in FIG.

As can be seen from the flowchart in FIG. 4, the difference between the two combustions is caused by the way oxygen diffuses, and the following factors affect this oxygen diffusion.

■Amount of combustion air (i.e., amount of oxygen) ■Mass of fuel ■Flow disturbance In order to perform blue flame combustion, either the amount of combustion air is sufficiently large or the mass of fuel is small (i.e., in the case of atomized fuel) Either the atomization is good and the size of the oil droplets is small), or the flow is highly turbulent and the fuel and oxygen need to be mixed sufficiently.

However, in the case of combustion using a gun-type burner that is often used for general kerosene combustion, it is difficult to achieve blue flame combustion even if the above conditions are met. This is because in general gun-type burners, a flame holder is installed immediately after the atomized fuel nozzle, and a stable flame is formed in this part, which becomes the ignition source for the subsequent fuel, as shown in Figure 3. Each stage of combustion proceeds simultaneously, and the sprayed oil droplets are ignited around the oil droplets before being thermally decomposed into a complete gaseous body with a light mass, and are surrounded by concentric diffusion flames and combust. do.

For this reason, oxygen diffusion is insufficient, and internal flame combustion occurs instead of blue flame.

In internal flame combustion (diffusion combustion), the diffusion of oxygen is through the flame of the diffusion flame method to the above layer on the surface of the internal oil droplets, and the mixing of fuel and air is due to the fact that the fuel is in the form of oil droplets. Due to its large mass, it must be promoted by large turbulence in the flow or by excessive air volume. For this reason, self-burning burners require measures to generate large turbulence in the flow (for example, generation of maximum impact flow), and also require the supply of an excessive amount of air.

In internal flame combustion, an oxidation reaction of colloidal carbon occurs, but if oxygen diffusion is insufficient at this time, this colloidal carbon is discharged as soot. Such insufficient diffusion of oxygen may occur due to local mixing defects even if the amount of oxygen is sufficient.

Insufficient oxygen diffusion also results in the emission of oxidized intermediates (often -carbon oxides).

The increase in the content of the above two combustion emissions becomes noticeable when the excess air ratio is lowered, and for this reason, it has been difficult to reduce the excess air ratio below a certain level in diffusion combustion.

In internal flame combustion, it is necessary to generate large turbulence in the flow to promote mixing, but since this is turbulence in the flow including the diffusion flame method during combustion, the noise is loud and was the main cause of combustion noise. Another disadvantage is that the more turbulent the flow is to achieve complete combustion, the louder the noise becomes. Additionally, to prevent such turbulence from occurring, it is common practice to narrow down the flow path at the rear of the flame holder, but in this case the flame is formed in a narrow space with some openings. So the sound gets louder.

On the other hand, in gastritis combustion, oxygen is diffused with vaporized gaseous fuel, so it is easy to diffuse, and there is little need for large turbulence in the flow or excessive amount of air.

Therefore, in blue flame combustion, it is possible to reduce the excess air ratio to almost the stoichiometric ratio.

In blue flame, the proportion of colloidal carbon produced is small;
In addition, since the gaseous fuel and oxygen are well diffused and mixed, even if the excess air ratio is lowered, soot and carbon oxide emissions are small, and it is possible to perform combustion close to complete combustion.

In this way, by lowering the excess air ratio, combustion is possible close to the theoretical combustion air amount, and because the mixing is good, the combustion area is narrowed, so the flame temperature becomes close to the adiabatic flame temperature, which increases the temperature. Become.

Blue flame combustion is quieter because it burns after mixing is complete, and it is quieter because the flame is formed at the open end.

As described above, blue flame combustion is clearly superior to internal flame combustion as a combustion method for liquid fuel vaporization burners.

(Problems to be Solved by the Invention) Therefore, the present invention provides a liquid fuel vaporizing burner, particularly a liquid fuel vaporizing burner having an output range of 23,000 to 57. oo.

) (The mission is to achieve complete blue flame combustion in a cat burner, and the nozzle area, combustion air region,
By completely separating the fuel vaporization region, mixing region, combustion region, and high-dry combustion gas circulation region, the oil droplets sprayed from the nozzle in the nozzle region are first ignited in the form of oil droplets in the fuel vaporization region. The fuel is vaporized into a gaseous state by the heat from the high-temperature combustion gas sucked through the circulation zone, and then the gaseous fuel is mixed with air in the mixing zone, and then stabilized in the combustion zone. However, in order to achieve complete gastritis combustion, in addition to oxygen diffusion (that is, mixing), the nozzle area, combustion air area, fuel vaporization area, mixing area, combustion area, and high temperature are required. Separation of the combustion gas circulation area is required.

However, in order to separate the nozzle region, the combustion air region, the fuel vaporization region, the mixing region and the combustion region, and the hot combustion gas circulation region, there must be mixing and flame formation in the fuel vaporization region. There should be no flame formation in the mixing zone.

Therefore, the problems to be solved by the present invention are to prevent the mixing of the oxygen-deficient high-temperature fuel vapor flowing into the fuel vaporization region and the oxygen-excess fuel-deficient mixture, and to prevent the formation of flame in the mixing region. The nozzle area, combustion air area, fuel vaporization area, and mixing area are designed to prevent this.

The goal is to completely separate the combustion zone and high-temperature combustion gas circulation zone.

(Means for Solving the Problems) The technical means taken by the present invention to solve the above-mentioned problems include a fuel spray nozzle, and an air system provided around the fuel spray nozzle, surrounding the nozzle and coaxially with the fuel spray nozzle. and a cylinder made of porous ceramic having water absorption properties and having a cylindrical part that opens at the rear, and that continues from the front end of the cylindrical part and expands forward at an angle slightly narrower than the spray angle of the nozzle. a burner cone having a widening part shaped like a shape, and provided in front of the fuel spray nozzle surrounding the fuel spray area of the guzzle and coaxially with the nozzle and the air outlet, and made of a porous ceramic having water absorbing properties; The bottom surface is formed into a hollow conical or hemispherical shape with an opening, the convex surface is directed toward the inside of the burner cone at the opening at the front end of the burner cone, and there is an appropriate distance between the outer circumferential surface and the rim of the opening. Set the burner control and set the air blowing speed to 1.
9IIl/SeC≧Blowing speed≧1Qm/sec.

(Function) The oil droplets sprayed from the fuel spray nozzle reach the burner cone and the inner surface of the rectifier plate, which are heated by the high-temperature circulating gas sucked in from the frontage of the cylindrical part of the burner cone.
- After being sucked into and held by the ceramic support surface, it is instantaneously vaporized by the heat of the burner cone and rectifying plate to become a primary vaporized fuel body.

Also, among the fine oil droplets that do not reach the burner cone and the inner surface of the baffle plate, those that reach the fuel vaporization region are vaporized by the heat of the high-temperature circulating gas and become secondary vaporized fuel bodies.

This vaporized fuel and the high-temperature circulating gas sucked through the high-temperature combustion gas circulation region flow along the inner surface of the burner, and the vicinity of the burner has an oxygen i of 91 degrees below the lower combustion limit. That is, an oxygen-deficient layer is formed near the inner surface of the burner cone, thereby preventing the formation of a flame in the fuel vaporization region.

On the other hand, the central part of the burner cone is the combustion air air region where the air blown out from the air outlet flows. Although some fuel droplets are mixed in, the amount of these fuels is extremely small and the concentration is below the lower flammability limit. That is, combustion is prevented.

As described above, suction of combustion gas into the burner cone is essential in the present invention, but if the diameter of the air outlet is too small, the air blows out at too high a speed, colliding with the current plate and pushing backward. When pressure is applied, the suction of circulating gas becomes worse and the combustion noise becomes louder.On the other hand, if it is too large, the inner diameter of the air flow is set to ≦948, and the air blowing speed is set to 10m/Se.
The optimum amount of high-temperature combustion gas is sucked into the burner cone due to the combination of C to 19 m/sec and the shapes of the nozzle cone and rectifying plate that reduce the resistance as much as possible.

Therefore, air flows in the combustion air region at the center of the burner cone, and in the fuel vaporization region near the cone wall surface, oxygen-deficient combustion gas is sucked in by the high-speed air flow and fuel gasified by the heat of the cone. Gas flows, and these two flows that are not within the flammability limit of each other do not mix inside the burner cone, and only mix at the baffle plate and the constricted part of the burner cone outlet, and then from the front end of the burner cone and the baffle plate part. A stable flame is formed in the combustion zone.

namely, the nozzle area, the combustion air area, and the fuel vaporization area.

Since the mixing zone, combustion zone, and high temperature combustion gas circulation zone are completely separated, perfect blue flame combustion can be obtained.

(Example) Hereinafter, an example of implementation of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal cross-sectional view of the main parts of a water heater equipped with a burner of the present invention.

In this illustrated example, the burner (
Δ) is a heat exchanger flange vibrator (1) with an output of 35000 Kcal/H and installed on the peripheral wall of a cylindrical combustion chamber (2).
0) and faces into the combustion chamber (2).

The burner (A) includes a fuel spray nozzle (3), an air outlet (4) provided around the fuel spray nozzle (3) surrounding the nozzle (3), and a fuel spray area of the fuel spray nozzle (3). a burner cone (6) provided surrounding the burner cone (6); a current plate (8) provided at the outlet of the burner cone (6);
A flame-holding ring (9) is provided in front of the current plate (8).

The air outlet (4) is formed in a straight cylindrical shape that opens from the heat exchanger flange pipe (10) in a direction perpendicular to the axial direction of the combustion chamber (2), and the rear part is connected to the outside of the combustion chamber (2). J! Contact the wind path (12) at 1m <ii>.

Further, a nozzle holder (1) is provided coaxially within the air outlet (4), and the tip of the fuel spray nozzle (3) held in the nozzle holder (1) is at the front end of the air outlet (4). The opening faces the center of a burner cone (6), which will be described later.

This air outlet (4) must have Φ37≦inner diameter≦48, length/inner diameter>0.5, length>20'mm, and in this embodiment, the inner diameter is 40φ and the total length is 551TIT.
11.

Note that the diameter of the nozzle holder (1) is 21φ.

I'll send it again! Regarding the air blown out from the air outlet (4) by 1m (11), the wind fit is 0.5 to 1.
, 3 Nm/m, 19 m/sec≧Blowing speed≧1
In this example, the air volume is 0.8 Nm/m, and the blowing speed is 16 IIl/SeC.
is set to .

The fuel spray nozzle (3) is a nozzle with a spray angle of 60° and has a conventionally well-known structural form, and its rear part connects to the oil supply source (14) through an oil supply pipe 13) that passes through the nozzle holder (1) in the axial direction. Contact.

The oil pipe (13) is equipped with an electromagnetic pump (15) in the middle, and the nozzle (3) is operated by the electromagnetic pump (15).
The amount of oil sprayed is set to 4.34/H.

Incidentally, the above oil amount needs to be 2.6 to 7.017H.

The burner cone (6) has the shape shown, that is, a cylindrical portion with a straight or slightly tapered rear part (6a
) is formed, and at the same time, a conical widening part (6b) is formed at the front end of the cylindrical part (6a) and extends forward in a conical shape, and is held by a suitable holding member (17). The fuel spray nozzle (3) is provided coaxially with the fuel spray nozzle (3) in front of the air outlet (4), with a gap (5) existing between the air outlet (4) and the air outlet (4).

The burner cone (6) has a cylindrical part inner diameter>48φ, a cylindrical part inner diameter/air outlet inner diameter>1.3, an air outlet passage area/
(Cylindrical section cross-sectional area - air outlet cross-sectional area) (1) Cylindrical section cross-sectional area - air outlet cross-sectional area > O, 00077 m In this example, the inner diameter of the cylindrical section is 63φ, and the cylindrical section cross-sectional area - The cross-sectional area of the air outlet is 0.00173 m.

The burner cone (6) has a total length of 100m/m, and the expansion part (6b) expands forward at an expansion angle of 30', the front end of which is on the right side of the 104Φ inner diameter, and the rear end and air The gap (5) between the front end of the air outlet (4) has a width of 20 m/III.

The opening at the rear end of the burner cone (6) and the air outlet (
The gap (5) between the combustion chamber (2) and the burner cone (6) utilizes the negative pressure generated around it due to high-speed air blowing from the air outlet (4). This constitutes a suction port (5) for sucking inward.

The baffle plate (8) is formed into a conical or hemispherical shape with an open bottom, and is inserted into the burner cone (6) with its convex surface facing the burner cone (6). 6), and its outer periphery and burner cone (6) come out.

An annular gap (18) is formed between the opening and the mouth.

The current plate (8) has a total length of 451R/It and an opening diameter of 90φ, and the burner cone (8) is positioned so that its top is 82m/m from the front end of the air outlet (4). 6) It is inserted into the outlet and its front end protrudes forward by 7 m/m from the front end of the burner cone (6).

In addition, the current plate (8) has a 6Φ
Thirty-six small holes (7) are drilled.

The annular gap (18) formed at the outlet of the burner cone (6) by the baffle plate (8) and the burner cone (6) is the gap area/(air Passage area of outlet - (cross-sectional area of burner cone cylindrical part - cross-sectional area of air outlet)) > 1 gap area >0.00154-m', and burner cone (6)
0.00 to prevent backfire at the exit
154 pores (gap area < 0.00667 buds, in this example, 0.0 including 36 small holes (7))
It is formed at 0410m.

In addition, as long as the small hole (7) satisfies the above conditions for the annular gap (18), that is, the substantial outlet of the burner cone (18),
It is possible to slightly increase or decrease their number and diameter.

Above, the burner cone (6) and current plate (8) are made of silicon 4
It is made of porous ceramic made of 2% silicon nitride, 18% silicon nitride, and 40% clay, and has a porosity of 30%.

Incidentally, the porosity of the burner cone (6) is 50 to 20.
It can be changed within the range of %.

The flame-holding ring (7) is made of metal with excellent heat resistance and is formed into an annular body with a substantially V-shaped or U-shaped cross section, with the convex surface facing the current plate (6) and burner cone (5) side. rectifier plate (6
) is provided in front of the

The flame stabilizing ring (9) has an outer diameter of 130 Φ, an inner diameter of 104 Φ, which is the same diameter as the outlet of the burner cone (6), and a length of i5 m/m, with the rear end of the burner cone ( 6) Located in front of the current plate (8) at a distance of 12111 m/m from the front end.

In addition, (19) in the figure is the igniter, and the fuel spray nozzle (
A pair of air blowers are provided at positions close to air outlet (4) that do not obstruct the flow of air from the air outlet (4).

Then, at the burner (A>) that refuses, the blower II (11
) and the electromagnetic pump (15) are activated and the igniter (19) is ignited. First, the igniter is applied to the mixture of fuel sprayed from the fuel spray nozzle (3) and air blown from the air outlet (4). (19
) is ignited, and a yellow flame is formed in the center of the burner cone (6).

Furthermore, the air is blown out from the air outlet (4), thereby producing a suction effect and sucking the surrounding air.

As a result, the gap between the burner cone (6) inlet and the air outlet (4) is smaller than the burner cone (6) outlet.
That is, a circulating flow is generated through the combustion gas suction port (5) and into the interior of the cone (6).

After ignition, hot combustion gas is sucked into the burner cone 6) by the above circulation action, and the atomized fuel is instantaneously vaporized by the heat. The vaporized fuel forms an oxygen-deficient layer (a) with the circulating gas along the inner surface of the cone (6).
) A constriction part (2) formed between the outlet part and the current plate (8).
0> and is promoted to mix with the combustion air that has flowed through the center of the cone (6) at the core (20).

When the burner cone (6) inhales the combustion gas, the gold inside the burner cone (6) moves to the downstream part of the rectifying plate (8) at fi11,
At this point, the mixture ignites and becomes a blue flame.

On the other hand, oil droplets sprayed from the spray nozzle (3) and not vaporized by the suctioned combustion gas are removed from the burner cone (6).
It hits the inner circumferential surface, especially the inner circumferential surface of the expanded part, but the cone (6)
Since it is made of porous ceramic that absorbs water, it is once sucked into the ceramic and retained. Since the cone (6) is at a high temperature due to convective heat transfer by the high-temperature combustion gas, the inhaled fuel quickly evaporates and vaporizes and returns to the cone (6).
Flows to the outlet, mixes with air at the constriction part (20) of the baffle plate (8) and the cone (6) outlet [1], and in the downstream part of the baffle plate (8), that is, the concave part behind the baffle plate (8). ignite.

The concave portion behind the baffle plate (8) serves as the 81 station of the airflow, and high-temperature combustion gas remains in this portion, is released from the outlet of the cone (6), vaporizes, and ignites the fuel gas mixed with air. Become the source. Therefore, the small hole (7) made in the current plate (8)
A blue flame will rise from it.

In addition, the current plate (8) is made of porous ceramic that has the same water absorption properties as the burner cone (6).
In addition to rectifying airflow and serving as an ignition source, it can also function as a fuel vaporization surface similar to the burner cone (6).

Furthermore, the unburned gas that is ignited at the end of the current plate (8) flows along the inner and outer peripheral surfaces of the flame-holding ring (9) and enters the recess behind the flame-holding ring (9). do.

The four areas behind the flame stabilizing ring (9), like the recesses behind the baffle plate (8), serve as retention points for the airflow. It becomes a source of ignition for unburned gas. Therefore, the flame-holding ring (8)
A stable blue flame will appear at the end of the flame.

In addition, in this application, the output range is 23,000 to 57,000
Kcal/l-(N')ite (7) This relates to a vaporizing burner, but the same effects as the present invention can be expected for burners with higher outputs if the shape of the present application is similarly expanded.

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

(1) The blue flame stands at the front of the burner cone, resulting in complete combustion and high combustion efficiency (2) Complete combustion reduces the occurrence of 6.

(3) Combustion noise, that is, the operating sound of the burner, is low and quiet.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a liquid fuel vaporizing burner showing an embodiment of the present invention, and FIG. 2 is a front view with a portion cut away. FIG. 3 is a flowchart showing the process of burning kerosene. A... Burner 3... Fuel spray nozzle 4... Air outlet 5... High temperature combustion gas suction port 6... Burner cone 6a... Cylindrical part 6b...
Expansion part 8... Rectification spirit Applicant: Toto Kiki Co., Ltd. Representative: Masa Hayakawa Procedural amendment to August 2, 1980 Manabu Shiga, Commissioner of the Japan Patent Office Patent Application No. 101564, filed in 1988 No. 2, Name of the invention Liquid fuel vaporizing burner 3, Relationship to the case of the person making the amendment Name of patent applicant (AO8) Totokiki Co., Ltd. 4, Agent Showa Month/Date 6, Subject of amendment ( 1) Detailed description of the invention in the specification

Claims (1)

[Claims] A fuel spray nozzle, an air outlet recessed around the fuel spray nozzle and provided coaxially with the nozzle, and a cylindrical part made of water-absorbing porous ceramic and opened at the rear, and at the front end of the cylindrical part. The fuel spray nozzle has a cylindrical widening part that continuously widens forward and opens at a slightly narrower angle than the spray angle of the nozzle, and surrounds the fuel spray area of the nozzle in front of the fuel spray nozzle, so that the nozzle and the air The burner cone is installed coaxially with the air outlet, and the burner cone is made of water-absorbing porous ceramic and has a hollow conical or hemispherical shape with an open bottom, and a convex surface inside the burner cone at the opening at the front end of the burner cone. A baffle plate is provided coaxially with the burner cone with an appropriate distance between the outer circumferential surface and the rim of the opening, and the inner diameter of the air outlet is set such that Φ37≦inner diameter≦
A liquid fuel vaporization type burner having a diameter of 48 mm and having a blowing speed of air blown out from an air blowing port such that 191/sea≧blowout speed≧1Qm/sec.