JPH06249408A - Combustion device - Google Patents

Abstract

PURPOSE:To reduce generation of nitrogen oxides and stabilize combustion. CONSTITUTION:A burner head 1 comprises rich gas chambers 2 formed on both sides thereof and a mixing chamber 6 formed therein to be opened at a top thereof and connected at a lower portion thereof to an air port. Connected to the lower portion of the mixing chamber is a combustion tube body 7, of which an upper portion is formed to have a mountain shape, and a side wall of the mixing chamber is inclined to make the mixing chamber 6 into a venturi shape. In this manner, pressure variation in the mixing chamber becomes gentle and flow becomes smooth, so that a jet velocity at a lean gas flame port 4 is made uniform to stabilize a flame and reduce noises without causing any vibrating combustion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device which achieves low NOx and stable combustion.

[0002]

2. Description of the Related Art The conventional Bunsen combustion system is the most common combustion apparatus for domestic combustion appliances such as water heaters. However, this type of combustion apparatus has a drawback that a high temperature region is locally generated and NOx generation value is high. Have

To improve this, there is a rich / lean combustion system, which is effective in reducing NOx. For example, there is one disclosed in Japanese Patent Application Laid-Open No. 4-186004, in which a rich gas is produced in the central portion of a combustion tube forming a fresh gas flame port in the upper part of a mixing chamber producing a fresh gas, and a rich gas flame hole is formed on the upper surface. A combustion inner tube to be formed is arranged, and a dense high-temperature flame is formed in the central part and a light-side combustion is formed on both outer sides, so that no local high temperature region is generated and NOx is reduced.

However, when the central portion is on the dark side and both outer sides are on the light side, the outer portion of the light flame tends to be lifted and combustion becomes unstable. In order to solve this, the present applicant has previously formed the rich gas chambers 22 on both side surfaces of the burner head 21, as shown in FIGS. A mixing chamber 24 communicating with the mixing chamber 24 is formed, and a combustion pipe main body 25 is connected to a lower portion of the mixing chamber 24 to communicate with the rich gas chamber 22 and the mixing chamber 24 through the through holes 28 and 29. A combustion apparatus has been proposed in which a rich gas flame port 26 and a light gas flame port 27 are provided on the upper surface of the mixing chamber 24, and a light flame is formed in the central portion and a rich flame is formed on both outer sides.

With such a structure, lifting of the light flame is prevented and combustion is stabilized.

[0006]

However, in the above-mentioned one, since the combustion pipe main body 25 connected to the lower portion of the mixing chamber 24 has a flat upper surface, the flow of the fresh gas is disturbed at the upper portion. , The mixing property is good, but the ejection speed (ejection pressure) from the light gas flame port 27 is not uniform,
It was discovered that there are problems such as constant fluctuations, flame vibrations, and increased combustion noise.

An object of the present invention is to solve the above-mentioned problems and to provide a combustion apparatus in which the pressure fluctuation in the mixing chamber is small and the flow is uniformized, thereby reducing NOx and stabilizing combustion, and reducing noise. is there.

[0008]

In order to achieve the above object, the combustion apparatus of the present invention has a mixing chamber in the center and a rich gas chamber formed on both sides of the mixing chamber. A burner head provided with a rich gas flame port at the upper part of the gas chamber and a combustion tube body for supplying a mixture of fuel gas and air to the mixing chamber and the rich gas chamber are provided, and air is supplied to the mixing chamber from below the burner head. In the air inlet provided, the upper portion of the combustion tube main body is formed into a mountain shape so as to project into the mixing chamber, and the side wall of the mixing chamber is provided with an inclined portion that expands outward as it goes upward.

[0009]

[Operation] During combustion, the rich gas in the main body of the combustion tube is ejected and burned from the rich gas flame mouth to form a rich flame, and the light gas produced by mixing with air in the mixing chamber is supplied to the light gas flame mouth. Is formed to form a light flame. The generation of NOx is reduced by this rich / lean combustion. And, in the mixing chamber, since the venturi-shaped flow path is formed by the inclination of the side wall and the inclination of the upper part of the combustion tube body, the flow of the fresh gas produced by mixing with the inflowing air is not disturbed and the pressure is reduced. It fluctuates gently and flows smoothly, and burns at a stable jet velocity from the fresh gas flame nozzle. Therefore, the light flame formed on the upper portion of the flame is stable and does not generate oscillatory combustion, and also reduces combustion noise.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of the essential parts showing an embodiment of the present invention.
FIG. 2 is a cross-sectional perspective view of essential parts showing a connection state between the burner head and the combustion tube main body.

Reference numeral 1 denotes a burner head, which forms a rich gas chamber 2 on both sides in the longitudinal direction, a rich gas flame port 3 is provided on the upper surface, an upper part is opened inside, and a light gas flame port 4 is provided on the upper surface. A mixing chamber 6 that communicates with the provided air port 5 is formed.

Reference numeral 7 denotes a combustion tube main body connected to a lower portion of the mixing chamber 6 of the burner head 1, and a side wall of the combustion tube main body 7 is connected to a joint portion 8 formed to project from a lower portion of a side wall of the rich gas chamber 2 of the burner head 1. A communication passage 10 is formed between the protruding joint portions 8 by communicating with the rich gas chamber 2 through a through hole 9 provided in the lower air port 5 and the mixing chamber 6, and corresponds to the communication passage 10. The rich gas in the combustion tube body 7 is supplied to the rich gas chamber 2 and the mixing chamber 6 by communicating with the mixing chamber 6 through the through hole 11 provided on the side surface.

The upper portion of the combustion tube body 7 is formed in a mountain shape, and the side wall of the mixing chamber 6 corresponding to this is formed into an inclined surface,
The mixing chamber 6 is formed in a venturi shape having a narrowing portion 12 below. A partition plate 13 forms the light gas flame port 4. The through hole 11 is arranged in the narrowing portion 12.

At the time of combustion, the rich gas having a low excess air ratio generated in the combustion tube body 7 flows into the rich gas chamber 2 from the through hole 9,
Combustion is emitted from the rich gas flame port 3 on the upper surface to form a rich flame on both outsides of the burner head 1. Further, the rich gas ejected from the through hole 11 mixes with the air flowing in from the air port 5, is mixed and rectified in the Venturi-like flow passage in the mixing chamber 6 to make the internal pressure uniform, and the fresh gas having a high excess air ratio. Is generated and burned at a stable jet speed from the light gas flame port 4 provided on the upper surface to form a light flame at the central portion of the burner head 1.

Since the mixing chamber 6 is formed in the Venturi shape in this way, the flow of the mixed gas is not disturbed and the pressure fluctuation in the mixing chamber 6 is gentle and smooth, so that it is formed above the fresh gas flame port 4. The generated flame is stable, does not generate oscillatory combustion, and can reduce combustion noise.

Further, since the gas is ejected from the through hole 11 provided in the narrowed portion 12 of the venturi-shaped passage, the gas is stably supplied even when the air supply amount (supply pressure) is large at a high combustion amount. It can handle high loads smoothly.

[0017]

As described above, according to the present invention, since the venturi-shaped flow path is formed in the light mixing chamber, the pressure fluctuation in the mixing chamber is small, the ejection speed from the flame outlet is uniform, and the flame is stable. Noise can be reduced without generating vibration combustion.

Further, the generation of NOx can be reduced by eliminating the local high temperature region by the rich and lean combustion.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a cross-sectional perspective view of essential parts showing a connected state between the burner head and the combustion tube body of the same example.

FIG. 3 is a cross-sectional view of a main part showing a conventional example.

FIG. 4 is a cross-sectional perspective view of essential parts showing a connected state of the burner head and the combustion tube body of the same example.

[Explanation of symbols]

 1 Burner Head 2 Thick Gas Chamber 3 Thick Gas Flame Mouth 4 Light Gas Flame Mouth 5 Air Mouth 6 Mixing Chamber 7 Combustion Pipe Body 9 Through Hole 10 Communication Passage 11 Through Hole 12 Narrow Portion

Claims (1)

[Claims] 1. A burner head having a mixing chamber in the center and a rich gas chamber defined on both sides thereof, a light gas flame port on the upper part of the mixing chamber, and a rich gas flame port on the upper part of the rich gas chamber, and a mixing chamber. And a combustion pipe main body for supplying a mixture of fuel gas and air to the rich gas chamber, and an air inlet for taking air into the mixing chamber from below the burner head is provided. A combustion device, wherein the combustion device is formed so as to project into the mixing chamber, and a side wall of the mixing chamber is provided with an inclined portion that expands outward as it goes upward.