JPH05340512A - Liquid fuel combustion apparatus - Google Patents

Abstract

PURPOSE:To attain an instantaneous combustion, a reduction in noise level, downsizing of an apparatus and an increase in combustion turn down ratio by a method wherein liquid in swirl is spouted as a liquid film through a fine annular slit, atomized by a high-speed air flow and sent into a burner as a combustible mixed gas. CONSTITUTION:Liquid fuel reaches an inclined groove 30 from a liquid groove 26 and is spouted as a liquid film through an annular slit 28 between a film forming part 27 and a liquid hole 23 after turned into whirling flow in a whirling chamber 31. Simultaneously, atomizing air introduced through an air hole 37 and an air slit 35 is spouted at a high speed from an air nozzle 36. Therefore, the annular liquid film is atomized. Particulates sprayed into a spray chamber is mixed with air supplied from a primary air supply part and sent to a burner. Thereby, an excellent combustion characteristics can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid fuel combustion apparatus used as a heat source for hot water supply / heating equipment.

[0002]

2. Description of the Related Art In recent years, in oil burning equipment,
There is an increasing demand for expansion of the combustion control range, noise reduction, and miniaturization.

Conventionally, this type of liquid fuel combustion apparatus is roughly classified into an apparatus for atomizing liquid fuel by a spraying apparatus and burning the combustion particles as it is, and an apparatus for vaporizing and burning the liquid fuel once.

For example, in the former spray combustion apparatus, as shown in FIG. 4, the liquid fuel supplied from the fuel tank 40 is pressurized by the pump 41, passes through the fuel supply pipe 42, and is discharged from the pressure spray nozzle 43. It is sprayed into the combustion chamber 45 from the fuel ejection hole 44. The combustion air is blown by the blower fan 46 into the blower passage 4
7 and is supplied to the combustion chamber 45. Then, the fuel sprayed from the pressure spray nozzle 44 and the combustion air undergo a combustion reaction to form a flame.

In the latter vapor combustion apparatus, as shown in FIG. 5, the liquid fuel supplied from the fuel tank 48 is
A pump 49 passes through a fuel supply pipe 50 and a nozzle 51.
Are discharged as droplets to a high temperature vaporization chamber 54 formed by a vaporization cylinder 53 in which an electric heater 52 is embedded, and are heated and vaporized. The combustion air passes through the air passage 56 by the air blowing fan 55, and the throat portion 5 provided on the outer periphery of the nozzle 51.
7 is supplied to the vaporization chamber 54, mixed with the vaporized fuel there, and forms a flame in the flame port 59 provided in the combustion chamber 58.

[0006]

However, in the above-mentioned conventional spray combustion apparatus (FIG. 4), since the particle diameter of the liquid fuel ejected from the pressure spray nozzle 43 is large, the flame length becomes long and the apparatus can be downsized. was difficult. Further, in the combustion device, noise is not achieved when the particle size is large, because the combustion device is generated by a burst noise when the fuel particles boil rapidly due to the flame.

Further, when the jet pressure of the fuel is lowered in order to reduce the combustion amount, the jet velocity also decreases, the atomized particle diameter increases, and good combustion cannot be obtained, so that the combustion amount adjustment range is extremely narrow. Was becoming.

On the other hand, in the vaporization combustion device (FIG. 5), since the liquid fuel is vaporized and burned, the structure becomes complicated and electric power for heating the vaporization cylinder 53 and the vaporization chamber 54 is required. In addition, since the preheating time for raising the temperature is required, instantaneous ignition and combustion cannot be performed, and the instantaneousness is poor.

The present invention solves the above problems, and an object of the present invention is to provide a liquid fuel combustion apparatus capable of achieving instantaneousness of combustion, noise reduction, size reduction, and expansion of combustion amount adjustment range.

[0010]

In order to achieve the above object, a liquid fuel combustion apparatus of the present invention has a fuel nozzle having a liquid chamber to which the liquid fuel is supplied, and a liquid hole provided at the tip of the fuel nozzle. A small annular gap is formed between the core in the liquid chamber that regulates the supply amount of liquid fuel and the liquid hole formed at the tip of this core, and the height is almost the same as the tip of the fuel nozzle. The film forming portion set so that the liquid fuel is swirled on the upstream side of the film forming portion, and the liquid fuel is ejected from the gap between the liquid hole and the film forming portion provided on the outer periphery of the fuel nozzle. An air nozzle having an air ejection hole for supplying atomizing air to the liquid fuel, and a plurality of nozzle blocks formed by the air nozzle and the fuel nozzle are opposed to each other at a predetermined angle so as to collide the atomized particles. Liquidizer and fuel nozzle And fuel supply means for supplying a fee,
Air supply means for supplying atomizing air to the air nozzle,
A primary air supply unit that supplies primary air, a mixing chamber that mixes air with fuel particles ejected from an atomizer, a burner that is downstream of this mixing chamber and has a flame port, and a secondary that supplies air to this burner. It is composed of an air supply unit.

[0011]

According to the present invention, the swirled liquid is jetted as a stable thin liquid film from the annular minute gap, atomized by the shearing force of the high-speed air flow, and further made uniform by the collision. Since such fine particles are used, it is possible to obtain particles having a small particle size over a wide adjustment range of the spray amount of the liquid fuel with air having a low pressure and a small flow rate, and it is possible to increase the combustion amount adjustment range. In addition, since small fuel particles are sent to the burner as a combustible mixture in the state of being mixed with air, instantaneous ignition combustion is possible, and because premixed combustion is performed with atomized particles, flame shortening and equipment The size can be reduced. Further, since only minute fuel particles are burned, combustion noise can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in the figure, an atomization device 2 is provided in the atomization chamber 1, a fuel supply pipe 3 is connected to the atomization device 2, and liquid fuel is supplied from a fuel tank 4 in which a constant amount of liquid fuel is maintained. Electromagnetic pump 5 as fuel supply means
It is pressurized and pumped up and supplied to the atomizer 2.

Of the liquid fuel scattered in the atomization chamber 1, the liquid fuel condensed on the wall surface of the vaporization chamber 1 is returned to the fuel tank 4 by the return pipe 6. The air supply pipe 7 is provided to supply the atomization air sent from the air supply means 8 to the atomization device 2. A mixing plate 9 is provided on the downstream side of the atomizing device to form a mixing chamber 10, and a burner 11 is provided on the downstream side of the mixing chamber 10, so that the fuel particles mixed with the air have a pressure equalizing plate 1
2 is uniformly dispersed, and is supplied to the flame nozzle 13 and burned.

Further, a primary air supply unit 15 for supplying a part of the air sent from the blower 14 to the atomization chamber 1 and a secondary air supply unit 16 for supplying the burner 11 are provided, and the secondary air is a flame port. The secondary air holes (not shown) subdivided into 13 are supplied.

Next, details of the atomizer 2 will be described below with reference to FIG. As shown in the drawing, the atomizing device 2 is configured by arranging two nozzle blocks 17 symmetrically with respect to a center line YY 'at a predetermined angle.

The structure of the nozzle block 17 will be described below. 18 is a fuel nozzle, and a liquid chamber 19 is provided in the center,
It is connected to the nozzle holder 20. Reference numeral 21 denotes a fuel passage provided in the nozzle holder 20, and the liquid fuel is supplied to the liquid chamber 19 through a fuel passage 21 from a fuel supply pipe 22 connected to a rear portion of the nozzle holder 20. Fuel nozzle 18
A liquid hole 23 is formed at the tip end of the liquid crystal panel symmetrically with respect to the central axis X ₁ -X ₁ ′. Reference numeral 24 is a core mounted in the liquid chamber 19 of the fuel nozzle 18, and has an inclined portion 25, and a plurality of liquid grooves 26 are obliquely provided in the inclined portion 25. 27 is the core 2
4 is a film forming portion which is formed so as to form an annular minute gap 28 at the tip of No. 4 and the inner wall of the liquid hole 23 and to be substantially level with the tip of the fuel nozzle 18. Two
Reference numeral 9 denotes a swirl portion provided on the upstream side of the film forming portion 27, which has a central axis X ₁ -X ₁ 'on a cylindrical surface having a diameter substantially equal to the inner diameter of the liquid hole 23.
It has an inclined groove 30 that is angled with respect to. Reference numeral 31 is a swirl chamber provided between the swirl unit 29 and the film forming unit 27, which is formed by narrowing the outer peripheral surface of the film forming unit 27 one step deeper. 32 is a holding metal fitting for fixing the core 24, 3
Reference numeral 3 is a filter composed of a three-dimensional mesh structure having a pore diameter smaller than that of the gap 28. Reference numeral 34 denotes an air nozzle, and the nozzle holder 20 having the fuel nozzle 18 mounted therein is mounted in the air nozzle 34 so that a ventilation gap 35 is provided between the nozzle holder 20 and the tip of the fuel nozzle 18. Air nozzle 34
An air ejection hole 36 having a diameter substantially the same as or slightly larger than that of the liquid hole 23 is provided at the tip end in axial symmetry with respect to the central axis X ₁ -X ₁ ′. Further, an air hole 37 is provided on the side of the air nozzle 34.
Is provided, the air supply pipe 38 is connected, and an air passage 39 provided between the fuel nozzle 18 and the air nozzle 34.
Atomization air is blown from the air through the ventilation gap 35 to the air ejection hole 3
6 is supplied. The film forming unit 2
7. The turning portion 29 may be formed integrally with the inclined portion 28 of the core 24.

In the above structure, when a power source (not shown) is turned on, the electromagnetic pump 5 is operated, liquid fuel is sucked up from the fuel tank 4, and the liquid fuel is passed through the fuel supply pipe 22 in the nozzle holder 20 in a pressurized state. Is supplied to the fuel passage 21,
After removing fine dust and the like by the filter 33, it is sent to the liquid chamber 19. Since the core 24 is locked to the fuel nozzle 5 by the inclined portion 25, the liquid fuel supplied to the liquid chamber 19 reaches the inclined structure 30 of the swirling portion 29 from the liquid groove 26 and imparts the swirling force there. Then, after a uniform swirl flow is generated in the swirl chamber 31, the liquid is jetted as an annular liquid film flow from the minute annular gap 28 between the film forming portion 27 and the liquid hole 23. At this time, the turning portion 29
If the outer diameter of the cylinder and the inner diameter of the liquid hole 23 are fitted to each other so that they can be positioned in axial symmetry with respect to the central axis XX ′, the gap 28 becomes a uniform annular slit to form a uniform liquid film. You can

On the other hand, simultaneously with the fuel supply, the air supply means 8
The atomizing air is supplied from the air hole 37 to the air passage 39 through the air supply pipe 7, and is jetted at high speed from the air jet hole 36 through the ventilation gap 35. Therefore, the annular liquid film ejected from the gap 28 is sheared by the air flow and atomized.

Usually, in the spray combustion apparatus as shown in the conventional example of FIG. 4, in order to increase the spray amount, the pressure spray nozzle 4 is used.
Although the fuel injection hole 44 of No. 3 is made large, in this case, the liquid film to be ejected also becomes thicker, and therefore atomization air has a limit in atomization even if it is made to act. Further, when the liquid ejection hole 44 is large, if the amount of spray is reduced, the jet flow velocity becomes small, and stable liquid spray cannot be obtained. On the contrary, if the fuel injection hole 44 is made small to atomize, a small particle diameter can be obtained when the amount of spray is small, but when the amount of spray is increased, the jet flow velocity of the liquid becomes large, so that the action point of the atomizing air is The air flow velocity becomes slower, and the fuel jet holes 44 move to the downstream side, so that effective atomization cannot be performed and the particle size becomes rather coarse.

However, in this embodiment, by providing the regulated annular gap 28 between the liquid hole 23 and the film forming portion 27, the liquid is ejected as a thin liquid film flow, and the thin liquid film is directly and at high speed. Since the air for atomization is supplied, fine particles can be obtained. In this case, if you change the spray amount,
Naturally, the jet flow velocity also changes, but since it is an annular liquid film flow, the jet flow velocity of liquid does not change significantly, and the relative velocity of gas-liquid does not change much, so atomizing air can be effectively applied. It is possible and the particle size does not change significantly.

In the embodiment of the present invention, the swirling portion 16 imparts a swirling force to the liquid film flow, but this action can form a stable liquid film. This effect will be described with reference to FIG. However, FIG. 3 shows a state in which the atomizing air is not applied.

When the liquid film is ejected without giving a swirling force,
In addition to the negative pressure inside the annular liquid film flow, the surface tension of the liquid acts, so that the liquid film flow converges immediately after ejection as shown in FIG. Cannot be fully exerted.

On the other hand, according to the embodiment of the present invention, as shown in FIG. 3 (b), the centrifugal force acts by the swirling force, so that the phenomenon that the liquid film flow converges immediately after the jetting can be avoided and the stability can be improved. Since a liquid film can be formed, there is no risk of the liquid nozzle tip getting wet, and the end of the gas ejection hole can be set near the liquid film flow, so that the shearing force of the gas flow can be effectively applied. ..

Further, in the embodiment, since the nozzle blocks 17 are symmetrically opposed to the center line YY 'at two fixed angles, the fuel particles and the air jetted from the two nozzle blocks 17 are atomized. Of the mixed flow of each axis X ₁ −
The particles collide with each other at the intersection of X ₁ ′ and X ₂ −X ₂ ′ and atomize again. Therefore, very small particles can be effectively obtained in a wide adjustment range of the fuel spray amount.

In this way, the liquid fuel is atomized into the atomization chamber 1 by the atomizer 2 as a group of fine particles having a uniform particle size. The jet flow from one nozzle block 17 is considerably high speed, but since the jet flows collide with each other, the particle velocity after the collision is considerably reduced, and the atomizing air is one of the primary air. Since it acts as a part, a good mixed state of air and fuel particles is maintained. The particles sprayed in the atomization chamber 1 are introduced into the mixing chamber 10 while being mixed with the air supplied from the primary air supply unit 15, and are sufficiently mixed. This mixture of air and fuel is sent to the burner 11 while further increasing the degree of mixing, and the pressure equalizing plate 12 is used by the burner 11
After being uniformly dispersed over the whole, it becomes a combustible mixed gas and is supplied to the flame port 13 for premixed combustion. Further, the combustion air is supplied to the flame port 13 from the secondary air supply unit 16, so that a short flame is formed.

As described above, the liquid fuel injected from the fuel nozzle 18 is subjected to a shearing force due to a high-speed air flow to be atomized and further made into uniform fine particles by collision,
Since the secondary air is also supplied while being supplied to the flame nozzle 13 while being mixed with the atomizing air, excellent combustion characteristics can be obtained. Further, according to the atomizer 2 of the embodiment, it is possible to obtain uniform fine particles in a wide adjustment range of the spray amount, so that the combustion amount adjustment range can be widened. Since the atomizing air acts as a part of the primary air, premixed combustion can be performed at the flame nozzle 13.
Therefore, the combustion speed can be made higher than that of the diffusion combustion, and the flame at the flame port 13 can be shortened, so that the apparatus can be downsized. Further, since it is possible to obtain uniform and fine fuel particles, it is possible to reduce combustion noise caused by a burst noise when large fuel particles are rapidly boiled by a flame as in conventional spray combustion. Further, the primary air is supplied to the air-fuel mixture of atomized fuel particles and atomizing air to form a combustible air-fuel mixture, which is then supplied to the flame port 13, so that instantaneous ignition combustion is possible and instantaneousness is obtained. You can

[0027]

As is apparent from the above embodiments, the liquid fuel combustion apparatus of the present invention has the following effects.

(1) An annular minute gap is provided between the liquid hole provided at the tip of the liquid nozzle and the film forming portion, and atomizing air is applied to the liquid ejected from the annular gap on the outer periphery of the liquid nozzle. Since the gas nozzle having the gas ejection holes to be supplied is provided, the liquid can be ejected as an annular thin liquid film flow, and the shear force due to the high-speed gas flow can be applied to this liquid film flow. Therefore, it is possible to obtain particles having a very small particle size with a gas having a low pressure and a small flow rate. Further, since a liquid film flow is formed, the relative velocity of gas-liquid does not change significantly even if the amount of sprayed liquid is increased, and the atomizing gas can be effectively acted on, so that the particle size is large. No change will occur. Therefore, particles having a very small particle size can be obtained over a wide control range of the spray amount.

(2) A swirling force is applied to the liquid film flow by the swirling portion to avoid convergence of the liquid film flow, and a stable liquid film can be formed.
Therefore, since there is no fear of the tip of the liquid nozzle getting wet and the end of the gas ejection hole can be set in the vicinity of the liquid film flow, the shearing force of the gas flow can be effectively applied.

(3) The liquid fuel injected from the fuel nozzle can be atomized by applying a shearing force due to a high-speed air flow, and further, it is possible to obtain uniform fine particles by collision.
Since the fine particles are supplied to the flame port while being mixed with the atomizing air and the primary air, the secondary air is also supplied, so that excellent combustion characteristics can be obtained.

(4) Since the uniform fine particles can be obtained in a wide adjustment range of the spray amount by the shearing force and the collision force due to the air flow of the atomizer, the combustion amount adjusting range can be widened.

(5) Since it is possible to obtain uniform and fine fuel particles, it is possible to reduce combustion noise caused by a burst noise when large fuel particles are rapidly boiled by a flame as in conventional spray combustion. ..

(6) Since the atomizing air acts as a part of the primary air, premixed combustion can be performed at the flame mouth. Therefore, make the burning rate higher than diffusion burning,
Since the flame at the flame mouth can be shortened, the device can be downsized.

(7) Since primary air is supplied to the mixture of atomized fuel particles and atomizing air to form a combustible air-fuel mixture and is supplied to the flame port, instantaneous ignition combustion is possible.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a liquid fuel combustion apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of an atomization device in the device.

FIG. 3A is a cross-sectional view of a main part of an atomizer described for comparison with a swirl part of the device. FIG. 3B is a cross-sectional view of a main part showing an operation effect of the atomizer of the device.

FIG. 4 is a sectional view of a main part of a conventional liquid fuel combustion device.

FIG. 5 is a sectional view of the main part of the device.

[Explanation of symbols]

 2 atomizer 5 fuel supply means 8 air supply means 10 mixing chamber 11 burner 13 flame mouth 15 primary air supply section 16 secondary air supply section 17 nozzle block 18 fuel nozzle 19 liquid chamber 23 liquid hole 24 core 27 film forming unit 29 Swirling part 34 Air nozzle 36 Air ejection hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomonori Aso 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A fuel nozzle having a liquid chamber to which a liquid fuel is supplied, a liquid hole provided at a tip of the fuel nozzle, a core in the liquid chamber for regulating a liquid supply amount, and A film forming part formed at the tip of the core so as to form a slight annular gap between the liquid hole and the liquid hole, and the film forming part is set to have substantially the same height as the tip of the fuel nozzle; Side has a swirl part for swirling the liquid fuel, and an air ejection hole provided on the outer periphery of the fuel nozzle for supplying atomization air to the liquid fuel ejected from the gap between the liquid hole and the film forming part. An air nozzle, an atomizing device in which a plurality of nozzle blocks formed by the air nozzle and the fuel nozzle are opposed to each other at a predetermined angle so as to collide with a spray, and a fuel for supplying a liquid fuel to the fuel nozzle The supply means and the air nozzle And air supply means for supplying of air, a mixing chamber for mixing the primary air supply unit for supplying primary air, the fuel particles and the air ejected from the atomization device,
A liquid fuel combustion apparatus comprising a burner located downstream of the mixing chamber and having a flame port, and a secondary air supply section for supplying air to the burner.