JPS6251364B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a household heating appliance that is open to the room, and provides a combustion device that makes combustion gas cleaner, expands the stable combustion range, and is fully capable of varying the amount of combustion. It is something to do.

Conventional open-air combustion devices for home heating equipment have the disadvantage that the flame temperature becomes extremely high due to high-load combustion, and a large amount of nitrogen oxides (hereinafter referred to as NO _x ) are generated in the combustion gas. It was hot. Therefore, in combustion devices for heating appliances that are used for long periods of time, premix burners that perform surface combustion have been used to reduce _NOx .

However, premix burners that perform surface combustion form a stable and uniform flame at a certain combustion amount, but when the combustion amount is varied, the air-fuel ratio range is small, so the flame becomes uneven, and the combustion gas The amount of NO _x contained therein tended to increase.

A premix burner of a conventional combustion device will be explained based on FIG.

In Figure 2, 2 is a fan-shaped primary air port 3 at the bottom.
1 is an outer cylinder having an opening at the top, and this outer cylinder 2
A gas nozzle 32 is provided opposite to a primary air port 31 provided in the main body. Reference numeral 3 denotes a bottomed cylindrical combustion tube provided inside the outer cylinder 2, and the side wall of this combustion tube 3 is provided with numerous small holes. 6 is combustion tube 3
A mixing chamber 7 is formed between the bottom of the combustion chamber 2 and the outer cylinder 2, and is a premixed gas passage formed between the outer cylinder 2 and the side wall of the combustion cylinder 3.

In such a configuration, the fuel gas ejected from the gas nozzle 32 is supplied into the mixing chamber 6 from the primary air port 31 of the outer cylinder 2, and combustion air is also drawn into the fuel gas and pre-filled in the mixing chamber 6. The mixed gas becomes a mixed gas and is ejected to the combustion section in the combustion tube 3 through the premixed gas passage 7. The premixed gas ejected into the combustion tube 3 is ignited by an igniter (not shown) to form a flame. Since this flame has countless small holes in the combustion tube 3 in a certain combustion state, the area of the flame hole can be very large, so the load on the flame hole is small and surface combustion occurs. Therefore, the flame temperature becomes low and NO _x can be reduced.

However, due to changes in the amount of combustion air or small changes in combustion, the air-fuel ratio collapses, making it impossible to obtain a uniform flame, causing incomplete combustion locally, causing unburned gas to be discharged, and soot to form in the combustion tube. The components of the combustion gas will deteriorate significantly.

Furthermore, if the formed flame becomes non-uniform, locally high temperature areas will occur, leading to an increase in _NOx .

Also, when the combustion amount is varied, the air-fuel ratio becomes unbalanced, and as shown in Figure 3, the ejection pressure of the premixed gas becomes high in the high-temperature part of the upper part of the combustion tube 3, and as it becomes lower in the lower part, a pressure difference occurs. . Therefore, the flame becomes non-uniform and CO is generated and unburned gas is emitted, resulting in the disadvantage that the amount of combustion can hardly be varied.

The present invention provides an outer cylinder, a bottomed cylindrical combustion cylinder provided in the outer cylinder and having numerous small holes around the periphery, and a combustion cylinder located between the combustion cylinder and the outer cylinder and close to the combustion cylinder. a pressure regulating passage formed by the rectifier cylinder and the bottom peripheral edge of the combustion cylinder,
The above-mentioned conventional drawbacks are solved by forming a fuel gas mixing chamber in the lower part of the combustion tube by extending the straightening tube downward.

An embodiment of the present invention will be described below based on FIG.

Note that the same members as in the conventional example will be described with the same reference numerals.

In FIG. 1, reference numeral 1 denotes a vaporization chamber for vaporizing liquid fuel, and an outer cylinder 2 is provided above the vaporization chamber 1. As shown in FIG. Reference numeral 3 denotes a bottomed cylindrical combustion tube provided inside the outer tube 2, and the side surface is made of a wire mesh or a punching member. Reference numeral 4 denotes a rectifying cylinder located between the outer cylinder 2 and the combustion cylinder 3 and provided in the upper part of the vaporization chamber 1 close to the combustion cylinder 3, and has numerous small holes 5 around the periphery. Reference numeral 6 denotes a fuel gas mixing chamber formed by the straightening tube 4 and the bottom of the combustion tube 3. Reference numeral 7 denotes a premixed gas passage formed by the outer cylinder 2 and the rectifying cylinder 4. Reference numeral 8 denotes a pressure regulating passage formed between the bottom peripheral edge of the combustion cylinder 3 and the rectifying cylinder 4, and numeral 9 denotes a pressure equalizing passage formed between the side surface of the combustion cylinder 3 and the rectifying cylinder 4. Reference numeral 10 denotes a combustion air blowing passage provided through the side wall of the vaporization chamber 1, and a blowing fan 11 is attached to this ventilation passage 10. A fuel pipe 12 has a nozzle at one end facing into the vaporizing chamber 1 from the air passage 10, and the other end is connected to a fuel tank 14 via a fuel pump 13. 15 is vaporization chamber 1
This is a heater embedded in the side wall of the building.

In the combustion apparatus configured in this way, when the vaporization chamber 1 is heated by the heater 15 and the fuel pump 13 is driven to inject liquid fuel into the vaporization chamber 1 from the nozzle of the fuel pipe 12, the liquid fuel is instantaneously vaporized. be done.

On the other hand, by driving the ventilation fan 11, combustion air is supplied into the vaporization chamber 1 through the ventilation path 10, and the vaporized gas in the vaporization chamber 1 is guided to the mixing chamber 6. Then, the vaporized gas and the combustion air are uniformly mixed in the mixing chamber 6 to become a premixed gas, which is rectified by the small holes 5 provided in the rectifying cylinder 4 and uniformly ejected into the premixed gas passage 7. Ru. The premixed gas ejected into the premixed gas passage 7 is supplied into the combustion cylinder 3 from a small hole 5 provided around the straightening cylinder 4 through a pressure equalization passage 9, and is ignited by an igniter (not shown). surface combustion starts and a stable flame is formed in the flame hole (small hole) of the combustion tube 3.

In this combustion state, when the combustion amount is increased, the ejection pressure of the premixed gas applied to the upper part of the combustion tube 3 increases and the pressure inside the mixing chamber 6 also increases, as shown in FIG. The premixed gas is supplied into the combustion tube 3 from the pressure adjustment passage 8 provided between the bottom periphery of the combustion tube 3 and the straightening tube 4 through the pressure equalization passage 9. The pressure of the premixed gas applied to the upper part of the cylinder 3 is relaxed. Therefore, the pressure of the premixed gas applied to the entire circumference of the combustion tube 3 becomes uniform, and a stable flame is formed using the small holes of the combustion tube 3 as flame holes.

In addition, when the combustion amount is small, the pressure in the mixing chamber 6 is small, so the premixed gas does not flow out from the pressure adjustment passage 8 to the pressure equalization passage 9, and is rectified by the small hole 5 provided in the rectification tube 4. The mixed gas is uniformly injected into the mixed gas passage 7 and supplied to the combustion cylinder 3 via the pressure equalization passage 9. Therefore, there is almost no pressure difference in the premixed gas between the upper and lower parts of the combustion tube 3, and a stable flame can be formed.

Furthermore, by providing the straightening tube 4 close to the combustion tube 3, the radiant heat from the combustion tube 3 is transferred to the lower part of the straightening tube 3, and is cooled by the premixed gas ejected from the mixing chamber 6. Since the temperature of the combustion tube 3 is always maintained in a stable state, the generation of NO _x is suppressed and also has the effect of preventing flashback.

As is clear from the above description, the combustion apparatus of the present invention provides the following effects.

(1) By installing a straightening tube between the outer tube and the combustion tube, premixed gas is uniformly supplied to the twisted combustion tube, so a stable flame can be obtained in the combustion tube, thereby preventing the occurrence of localized high temperatures. It is possible to suppress the generation of NO _x .

(2) By arranging the combustion tube and the straightening tube close to each other and extending the lower part of the straightening tube, the heat generated in the combustion tube is cooled by the premixed gas through the straightening tube, which reduces the generation of NO _x . In addition to being suppressed, it is also possible to obtain the effect of preventing flashback.

(3) By forming a pressure adjustment passage between the bottom periphery of the combustion tube and the straightening tube, even if the combustion amount is increased and the pressure in the mixing chamber and premixed gas passage becomes high, the pressure adjustment passage can be connected to the pressure equalization passage. Since the premixed gas flows out to the combustion chamber, the premixed gas supplied to the combustion tube becomes uniform, and a stable combustion state is obtained.
It can also be used to vary the amount of combustion.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a combustion device showing an embodiment of the present invention, FIG. 2 is a sectional view of a combustion device showing a conventional example,
FIG. 3 is a characteristic diagram showing the ejection pressure of premixed gas in the combustion tube of the combustion device. 2... Outer tube, 3... Combustion tube, 4... Rectifier tube, 6
...Mixing chamber, 8...Pressure adjustment passage.

Claims (1)

[Claims] 1. An outer cylinder, a bottomed cylindrical combustion cylinder provided within the outer cylinder and having numerous small holes around the periphery, and a combustion cylinder located between the combustion cylinder and the outer cylinder and located close to the combustion cylinder. A combustion chamber consisting of a rectifier tube and a pressure adjustment passage formed by the rectifier tube and the bottom peripheral edge of the combustion tube, and a fuel gas mixing chamber formed in the lower part of the combustion tube by extending the rectifier tube downward. Device.