JP3414067B2 - Combustion equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device for injecting and burning fuel gas.

[0002]

2. Description of the Related Art Generally, as a combustion apparatus of this type, there is one that burns gas of liquid fuel obtained by vaporizing gas or kerosene. Hereinafter, description will be made by taking as an example a combustion device that combusts the liquid fuel gas. Such a combustion device is shown in FIG.
It is configured as shown in.

That is, first, fuel is supplied to the tank 26 from the cartridge tank 28, and the fuel in the tank 26 is supplied to the carburetor 29 by the pump 27. Then, it is vaporized by the vaporizer 29 to become a gas, which is ejected in the horizontal direction from the nozzle 30. The gas ejected from the nozzle 30 is ejected into the mixing pipe 31 provided on the downstream side of the carburetor 29 while being sucked by the ejector effect in the small diameter portion of the mixing portion 31 by the ejector effect and mixed there. , Is supplied to the line-shaped burner portion 32 integrated with the mixing pipe 31 and burned.

The generated combustion exhaust gas is guided upward by a combustion cylinder 33 arranged so as to cover the periphery of the burner portion 32, and mixed with the indoor air flow from the blower 35 by a duct 34 covering the combustion cylinder 33. It is then discharged as warm air and used for heating. Further, in this combustion apparatus, when the fuel supply amount is adjusted by changing the driving frequency of the pump 27 or the applied voltage, the primary air amount also increases / decreases accordingly, and the combustion amount is changed while the fuel / air ratio is kept constant. You can do it.

[0005]

However, in such a conventional combustion apparatus, since the burner portion 32 has a horizontally long line shape, it is difficult for the flame to be uniform left and right.
Inevitably, combustion at both ends tends to be disturbed, and since combustion flame is blown directly above, it is difficult to suppress the flow, and lift combustion is likely to occur. Further, there is also a problem that the burner portion 32 is easily deformed due to the non-uniform temperature because of the line shape even with age. Further, since the mixing pipe 31 and the burner portion 32 are arranged separately from the vaporizer 29, the heat of the burner portion 32 is removed from the vaporizer 29.
There is also a problem that it is difficult to make a structure for recovering it, and the burner section 32 is horizontally long, and thus the dimensions of the device are also horizontally long.

[0006] Conventionally, in order to solve such a problem, a combustion apparatus as shown in Fig. 5 has been proposed. That is, in this combustion device, the gas of the fuel vaporized in the vaporizer 36 is ejected vertically upward from the nozzle 37, and the primary air sucked by the ejector effect generated at that time is integrally formed in the vaporizer 36. The gas is supplied into the pipe 38 to mix the gas and the primary air in the mixing pipe 38,
From the upper opening of the mixing tube 38, a burner cylinder 39 having a heavenly cylindrical shape
Mixing pipe 3
The mixed gas is ejected from a large number of flame holes 40 provided in the lower peripheral wall of the burner cylinder 39 so as to flow downward to the outer periphery of the burner cylinder 38 and burned there.

In the combustion device having such a structure, the mixing pipe 3
The mixed gas flows back around the outer periphery of 8 and the mixed gas is uniformly ejected from a number of flame holes 40 provided in the lower peripheral wall of the burner cylinder 39 for combustion, so that the flame is uniform and the combustion flame is in the outer peripheral direction. The lift flame can be suppressed with a simple structure in which the burner ring 41 is provided on the outer periphery of the combustion flame so that the combustion flame flows upward.

However, the mixing tube 3 is placed in the burner cylinder 39.
Since 8 is located, the temperature of the mixing pipe 38 rises due to the radiant heat of the flame formed in the flame hole 40,
There was a tendency that flashback was likely to occur because the temperature of the mixed gas of the fuel gas and the air flowing inside and the outer circumference of the mixing pipe 38 was increased.

Further, the outer peripheral wall of the mixing tube 38 and the burner cylinder 3
Since the cross-sectional area between the inner peripheral wall of 9 and the inner peripheral wall of the mixing tube 9 is wider than the cross-sectional area of the upper opening of the mixing tube 38, the flow velocity of the mixed gas is reduced to cause stagnation and facilitate flashback. Further, since the cross-sectional area between the outer peripheral wall of the mixing tube 38 and the inner peripheral wall of the burner cylinder 39 is constant and is wider than the cross-sectional area of the upper opening of the mixing tube 38, the flame formed in the flame hole 40. There is a problem in that it is difficult to balance the combustion due to the difference in the jetting amount of the mixed gas between above and below.

If the height of the burner cylinder 39 is reduced in order to make the burner compact, the length of the mixing pipe 38 becomes insufficient, and the ejector effect of the fuel gas ejected from the nozzle 37 becomes weak, and the primary There is a problem that the amount of sucked air is reduced and combustion flames are easily disturbed, and that disturbances such as wind easily cause yellow fire, CO, odor, and misfire.

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and has as its first object the prevention of flashback and noise reduction, and the second object to adjust the combustion balance above and below the flame holes. The third purpose is to achieve good combustion while achieving compactness.

[0012]

In order to achieve the first object, the present invention uses a nozzle for ejecting fuel gas and an ejector effect of the fuel gas ejected from the nozzle on the downstream side of the nozzle. A bottomless cylindrical mixing pipe with inlets for sucking in primary air facing each other, and the upper opening side of the mixing pipe so as to cover the mixing pipe, and a large number of flame openings were formed on the lower peripheral wall. A top tube-shaped burner tube is provided, and an outer tube of the mixing tube is provided at a position substantially dividing the space between the lower portion of the mixing tube and the flame hole of the burner tube.

In order to achieve the second object, the lower contact portion between the mixing tube and the mixing tube outer cylinder is provided with a gap through which a mixed gas of fuel and air flows.

Further, in order to achieve the third object, a taper-shaped mixing tube outer cylinder lid in which the upper end of the mixing tube outer cylinder and the upper end of the mixing tube are hollow is formed integrally with the mixing tube outer cylinder. It was configured.

[0015]

According to the present invention, due to the above-mentioned structure, the temperature of the mixing tube is controlled by the mixing tube outer cylinder provided between the lower outer periphery of the mixing tube and the flame hole blocking radiation of the flame formed in the flame hole. By lowering and maintaining the temperature of the mixed gas of the fuel gas and the primary air flowing in the inner and outer circumferences of the mixing tube lower than before, the occurrence of flashback is reduced. In addition, by narrowing the cross-sectional area of the mixed gas flow path between the outer circumference of the mixing tube outer cylinder and the flame holes, the flow velocity of the mixed gas is increased and rectified to prevent stagnation until the mixed gas is ejected from the flame holes. Makes it less likely to occur and reduces the occurrence of flashback. Further, due to the sound insulation effect, it is possible to reduce the jet noise of the fuel gas jetted from the nozzle, the inflow noise of the mixed gas into the mixing pipe, and the mixing noise in the mixing pipe.

Further, according to the second structure, the mixed gas flowing between the outer circumference of the mixing tube and the inner circumference of the mixing tube outer cylinder flows from the gap provided in the lower contact portion between the mixing tube and the mixing tube outer cylinder. The amount of gas ejected from the lower part of the flame hole increases. By adjusting the opening area of this gap, the combustion balance, flame holding power, and carburetor temperature can be appropriately adjusted without changing the area of the flame holes.

Further, according to the third structure, the cross-sectional area of the mixed gas flow passage between the upper opening of the mixing tube and the combustion section of the burner cylinder is gradually increased, and the flow velocity of the mixed gas is extremely reduced. There is no turbulence due to the generation of parts or vortices, and the length of the mixing tube is as if it were long, and even if the mixing tube is short, that is, even if the burner cylinder is compact in size, sufficient primary air can be sucked in, and this primary The air and fuel gas are sufficiently mixed, and good combustion becomes possible.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

First, the construction of a warm air warming device using the combustion apparatus of the present invention will be described with reference to FIG. 1 is the body case,
A tank 2 holding a liquid fuel and a detachable cartridge tank 3 are arranged above the tank 2 on the lower side thereof. 4 is a pump mounted on the upper surface of the tank 2,
The oil supply pipe 5 is led out from the upper end to supply fuel to the combustion device 6.

Reference numeral 7 is a combustion cylinder for guiding the combustion gas from the combustion device 6 to the upper side, and a blower 8 for taking in and delivering the indoor air flow is arranged at the back of the combustion cylinder. Reference numeral 9 denotes a duct that mixes the combustion exhaust gas from the combustion cylinder 7 and the indoor air flow to generate warm air.
A control unit 10 controls the combustion of the combustion device 6 and the blower 8. The control unit 10 controls the pump 4, the blower 8 and the like in a predetermined sequence based on an operating condition signal input from the operation unit. .

Next, a first example of the structure of the combustion device 6 is shown in FIG.
Will be explained. 11 is a substantially ring-shaped burner receiving seat,
A vaporizer 12 is integrally formed on the burner receiving seat 11 toward the center thereof and is adapted to be supplied with fuel from the pump 4 so as to vaporize this fuel into a fuel gas. Has become. Reference numeral 13 is a vaporization element provided in the vaporizer 12 for increasing the vaporization efficiency of fuel. 14 is a heater for keeping the vaporizer 12 at a predetermined temperature,
The temperature is controlled by the output from the control unit 10 based on the input from the thermistor 15 that detects the temperature of the carburetor 12. Reference numeral 16 denotes a nozzle integrally attached to the end portion of the vaporizer 12, which ejects fuel gas from the vaporizer 12.

Reference numeral 17 denotes a bottomless cylindrical mixing tube mounted on the burner receiving seat 11 so as to be located above the nozzle 16. The inlet 17A of the mixing pipe 17 is formed in a throat shape, faces the nozzle 16, and is sucked by the fuel gas ejected from the nozzle 16 and the ejector effect by the ejection of the fuel gas. It is designed to mix with air.

Reference numeral 18 designates a burner cylinder having a heavenly cylindrical shape which is provided so as to cover the mixing pipe 17 from the side of the upper opening 17B so as to overlap with the burner receiving seat 11, and has a tapered upper portion and a plurality of flame holes on the lower peripheral wall. 19 is formed to form a combustion section 20. Further, a mixing tube outer cylinder 25 is formed on the coaxial circumference at a position where the space between the outer peripheral portion of the mixing tube 17 and the combustion section 20 is roughly divided into two. A gap 25A is provided in the contact portion between the lower portion of the mixing pipe outer cylinder 25 and the mixing pipe 17, and the mixed gas of the fuel gas and the primary air passes through the gap 25A and is ejected from the flame hole 19. To burn.

Further, the burner section 20 of the burner cylinder 18 has a large number of flame holes 19 so that the total area thereof can be increased, and at the same time, it is expanded in a cylindrical shape in order to promote diffusion and mixing of the mixed gas and equalization. There is.

Reference numeral 21 denotes an upwardly tapered burner ring attached to the burner receiving seat 11 so as to surround the outer periphery of the flame hole 19, and 22 denotes a heat receiving portion formed on the burner receiving seat 11.
Reference numeral 23 is an ignition device.

In the above structure, the cartridge tank 3
The liquid fuel supplied from the tank 2 to the tank 2 so as to maintain a constant oil level is sucked up from the tank 2 by the pump 4 and sent to the carburetor 12 of the combustion device 6 via the oil feed pipe 5. The sent fuel is vaporized in the carburetor 12 kept at a predetermined temperature or higher by the heater 14 and becomes high-pressure fuel gas and is ejected from the nozzle 16. At that time, the carburetor 12 sucks the primary air by the ejector effect. Is mixed in the mixing pipe 17 provided on the downstream side of the
It is ejected from the flame holes 19 of the combustion section 20 and is ignited by the ignition device 23 and burned. And the generated combustion exhaust gas is the combustion cylinder 7
Of the room air mixed with the indoor air flow from the blower 8 in the duct 9 and discharged as warm air to be used for heating. Then, the control unit 10 controls the heater 14, the pump 4, the blower 8 and the like in a predetermined sequence based on the condition set by the operation unit to start and stop the operation.
In addition, operation control such as changing the combustion amount is performed.

Now, the combustion in the burner cylinder 18 will be described a little more. The fuel gas ejected from the nozzle 16 flows into the mixing pipe 17 provided on the downstream side of the carburetor 12 while being sucked with the primary air by the ejector effect, and is mixed therewith. 18 is discharged into 18 and flows back around the outer periphery of the mixing pipe 17,
A large number of flame holes 1 provided in the combustion section 20 below the burner cylinder 18.
Eject from 9 and burn.

At this time, since the upper portion of the burner cylinder 18 is tapered, the flow passage area from the mixing pipe upper opening 17B to the combustion portion 20 gradually increases, and the mixed gas diffuses in this portion. The mixing and the uniformization of pressure are promoted, and the mixture is uniformly ejected from the flame holes 19 to form a uniform flame. The flame forming direction is controlled so that the flame is directed upward by the burner ring 21 provided so as to be located on the outer periphery thereof, and stable combustion without lift is performed. Further, the heat receiving portion 22 is heated by the flame formed in the combustion portion 20 of the burner cylinder 18, and the heat recovery action from this flame keeps the temperature of the carburetor 12 at a certain temperature or higher. It is possible to reduce part or all of the energization.

By the way, this combustion device is constructed so that flashback is unlikely to occur. The reason will be described in detail below.

First, the fuel gas ejected from the nozzle 16 flows into the mixing pipe 17 provided on the downstream side of the carburetor 12 and is mixed while sucking the primary air by the ejector effect, and the upper opening of the mixing pipe 17 is opened. Burner tube 1 from section 17B
8 is discharged to the inside of the burner tube 8 and flows back around the outer circumference of the mixing tube 17, and a large number of flame holes 19 are provided in the combustion section 20 below the burner cylinder 18.
Ejects from and burns. At this time, the mixing tube outer cylinder 25 blocks the radiant heat from the flame formed in the flame hole 19, and the mixing tube 1
In order to prevent 7 from being overheated, the temperature of the mixed gas of fuel and primary air flowing inside and around the mixing tube 17 can be kept relatively low, and the occurrence of flashback can be reduced. Further, the mixing pipe outer cylinder 25 is provided, and the mixing pipe outer cylinder 25
By narrowing the mixed gas flow passage cross-sectional area between the outer periphery of the mixed gas and the combustion section 20, the flow velocity of the mixed gas is increased and further rectified, so that stagnation until the mixed gas is ejected from the flame hole 19 is less likely to occur. However, the occurrence of flashback can be reduced. Even if a flashback occurs and the flame enters the inside of the combustion section 20, the flame is cooled by the mixing tube outer cylinder 25 and the combustion is not continued, so that the persistence of the flashback can be reduced. .

Further, the sound of the fuel gas ejected from the nozzle 16, the sound of the mixed gas flowing into the mixing pipe 17, and the sound of the fuel gas mixing with the primary air in the mixing pipe 17 are generated. By providing the mixing tube outer cylinder 25, sound can be insulated and noise generated from the flame port 19 can be reduced.

The lower portion of the mixing tube outer cylinder 25 and the mixing tube 17
By providing the gap 25A in the contact portion with the mixed gas, the mixed gas flows between the inner circumference of the mixing tube outer cylinder 25 and the outer circumference of the mixing tube 17, and is ejected from the flame opening 19 through the clearance 25A. The amount of the mixed gas ejected from the lower part of 19 can be increased. Therefore, by adjusting the opening area of the gap 25A, the amount of the mixed gas ejected from the upper and lower parts of the flame opening 19 can be adjusted, and the combustion balance can be achieved without changing the opening area and the shape of the flame opening 19. The flame holding power of the flame and the temperature of the vaporizer 12 can be adjusted.

Next, a second example of the structure of the combustion device 6 will be described with reference to FIG. The same parts as those described above are denoted by the same reference numerals, and the description thereof will be omitted. Only different parts will be described. Reference numeral 18 is a burner cylinder attached so as to cover the mixing pipe 17, and the upper portion has a tapered shape, and the lower peripheral wall has a large number of flame holes 19 to form a combustion portion 20. The mixing tube outer cylinder 25 is formed on the coaxial circumference at a position that substantially bisects the space between the outer lower outer periphery of the mixing tube 17 and the combustion section 20, and the upper end of the mixing tube outer cylinder 25 and the mixing tube. A mixing pipe outer cylinder lid 42 having a tapered shape with the upper end of 17 is formed integrally with the mixing pipe outer cylinder 25. The mixed gas passage cross-sectional area A between the upper opening 17B of the mixing pipe 17 and the combustion portion 20 of the burner cylinder 18 is gradually increased.

By the way, in this combustion apparatus, even if the burner cylinder 18 is compact, it can suck sufficient primary air. The reason will be described below.

When the vaporized fuel gas is ejected from the nozzle 16, it becomes a driving flow, and the surrounding air is dragged by the negative pressure generated around the ejection of the driving flow and the viscosity of the driving flow and mixed. Throat entrance 1 of tube 17
It enters from 7A (curved portion at the inlet), the driving flow and this primary air are mixed, the pressure is increased by the cylinder portion 17C (diffuser portion) of the mixing pipe 17, and the mixture is discharged into the burner cylinder 18 from the upper opening 17B. To be done.

The size of the throat inlet portion 17A is determined by the ratio of the area of the flame holes, and is influenced by the roughness of the inner wall of the mixing tube 17 and the like.
%, When rough, 45 to 60%, the primary air suction property is good, and in practice, a high suction amount is obtained at 30 to 70% of the flame hole area. In principle, the diffuser portion 17C is enlarged without changing its cross-sectional area so that the mixed gas of the primary air and the fuel gas flowing through the diffuser portion 17C allows appropriate expansion without causing a vortex flow. The length of the diffuser portion 17C is the throat inlet portion 17
A suitable length is 6 to 10 times the diameter of A, and the diameter is expanded at an angle of 4 to 10 along the flow of the mixed gas.

However, if the height of the burner cylinder 18 is lowered due to restrictions on the structure of the main body, such as the easiness of tilting of the equipment and the maintainability, the length of the mixing pipe 17 becomes insufficient, and the vaporizing gas ejected from the nozzle 16 is vaporized. The ejector effect of gas becomes weak.

However, according to the structure of this combustion apparatus, the cross-sectional area A of the mixed gas flow passage from the upper opening 17B of the mixing pipe 17 to the combustion section 20 gradually increases, and the mixed gas is extremely mixed. There is no turbulence due to the generation of vortex or the part where the flow velocity decreases, and the length of the mixing pipe 17 becomes as if it were long, and the ejector effect generated in the mixing pipe 17 is significantly large even if the length of the mixing pipe itself is short. To increase. This depends on the amount of combustion, but experiments show that
% UP. Therefore, sufficient primary air can be sucked in without increasing the length of the mixing pipe 17, that is, without enlarging the burner cylinder 18, and good combustion can be achieved.

Also in this configuration, the mixing tube outer cylinder 2
In order to prevent radiant heat from the flame formed in the flame hole 19 by 5 and prevent the mixing pipe 17 from being overheated, the temperature of the mixed gas of fuel and primary air flowing inside and outside the mixing pipe 17 is kept relatively low. Therefore, the occurrence of flashback can be reduced. Further, by providing the mixing pipe outer cylinder 25, the cross-sectional area of the mixed gas flow passage is narrowed, the flow velocity of the mixed gas is increased, and the flow is further rectified to generate stagnation until the mixed gas is ejected from the flame hole 19. It can be made difficult and the occurrence of flashback can be reduced. Even if a flashback occurs and the flame enters the inside of the combustion section 20, the flame is cooled by the mixing tube outer cylinder 25 and the combustion does not continue, so the sustainability of the flashback can be reduced. .

Further, the mixing pipe outer cylinder 25 is provided for the sound of the fuel gas ejected from the nozzle 16, the sound of the mixed gas flowing into the mixing pipe 17, and the mixing sound in the mixing pipe 17. As a result, sound can be insulated and noise generated from the flame port 19 can be reduced.

In the above-described embodiment, the combustion device having the structure in which the gap is provided in the lower contact portion between the mixing pipe 17 and the mixing pipe outer cylinder 25 has been described, but the gap may not be provided, and the other components may also be configured. Any configuration may be used as long as the object of the present invention is achieved.

[0042]

As described above, in the combustion apparatus of the present invention, the mixing tube outer cylinder blocks the radiant heat from the combustion section,
Also, the temperature of the mixed gas of the fuel gas and the primary air can be kept relatively low, and the occurrence of flashback can be reduced. Further, by narrowing the cross-sectional area of the mixed gas flow path, increasing the flow velocity, and further rectifying, stagnation until the mixed gas is ejected from the flame holes is less likely to occur, and the occurrence of flashback can be reduced. Even if a flashback occurs and the flame enters the inside of the combustion section, the flame is cooled by the outer tube of the mixing tube and the combustion does not continue. Therefore, the sustainability of the flashback can be reduced.

Furthermore, the sound of the fuel gas ejected from the nozzle, the sound of the mixed gas flowing into the mixing pipe, and the mixed sound in the mixing pipe are insulated by providing the mixing pipe outer cylinder to reduce noise. Can be reduced.

Further, regarding the structure in which the taper-shaped mixing tube outer cylinder lid, which is formed by wrapping the upper end of the mixing tube outer cylinder and the upper end of the mixing tube, is integrally formed with the mixing tube outer cylinder, It is possible to increase the ejector effect of the fuel gas without increasing the length, to allow sufficient suction and mixing of the primary air, and to achieve good combustion while achieving compactness.

[Brief description of drawings]

FIG. 1 is a sectional view of a combustion apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a combustion device according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a main part of a warm air heater using the same combustion device.

FIG. 4 is an explanatory view of main parts of a warm air heater using a conventional combustion device.

FIG. 5 is a cross-sectional view of essential parts showing another conventional combustion apparatus.

[Explanation of symbols]

16 nozzles 17 Mixing tube 18 burner cylinder 19 flame holes 20 Combustion part 25 Mixing tube outer cylinder 42 Mixing tube outer cylinder lid

Continuation of the front page (56) Reference JP-A-4-76301 (JP, A) JP-A-4-353303 (JP, A) JP-A-6-101814 (JP, A) JP-A-8-121718 (JP , A) JP-A-6-18010 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F23D 11/02 F23D 11/40-11/44

Claims (3)

(57) [Claims] 1. A bottomless cylindrical shape in which a nozzle for ejecting fuel gas and an inlet portion for sucking primary air by an ejector effect of the fuel gas ejected from the nozzle are arranged on the downstream side of the nozzle so as to face each other. The mixing pipe and a burner cylinder having a heavenly cylinder which is provided from the upper opening side so as to cover the mixing pipe and has a large number of flame holes formed in the lower peripheral wall, and the lower part of the mixing pipe and the above A combustion device in which a mixing tube outer cylinder is provided at a position that roughly divides the space between the burner cylinder and the flame hole. 2. The combustion apparatus according to claim 1, wherein a gap through which a mixed gas of fuel and air flows is provided in a lower contact portion between the mixing pipe and the outer cylinder of the mixing pipe. 3. The combustion apparatus according to claim 1, wherein a mixing pipe outer cylinder lid having a tapered shape in which the upper end of the mixing pipe outer cylinder and the upper end of the mixing pipe are swollen is integrally formed with the mixing pipe outer cylinder.