Combustion – Mixer and flame holder
Reexamination Certificate
2003-01-21
2004-06-08
Basichas, Alfred (Department: 3743)
Combustion
Mixer and flame holder
C431S278000
Reexamination Certificate
active
06746236
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a combustion apparatus, and more particularly relates to a combustion apparatus adapted for use with a hot-water supply system, a boiler or the like.
2. Related Art
The “thick and thin fuel combustion” method known in the art is designed to burn a fuel gas in its thin state. At least one main flame formed by burning a thin gas and at least one auxiliary flame formed by burning a thick gas will be jetted in juxtaposition to each other in this prior art system. In detail, such a thin gas for forming the main flame is composed a volume of the gas premixed with an amount of air whose volume is about 1.6 times as much as the theoretical air for said gas. A thick gas for forming the auxiliary flame contains a lesser amount of air.
In the thick and thin fuel combustion method, the fuel gas is burned with such an excess of air so that flame temperature is kept relatively lower to produce a less amount of nitrogen oxides. Thus, some types of current house-held water heater are constructed using such burners of the thick and thin fuel combustion system.
An example of thick and thin fuel combustion apparatuses having been widely used is disclosed in the Japanese Patent Laying-Open Gazette No. 10-47614.
In the combustion apparatus shown in the Gazette No. 10-47614, a first array of main burner ports for jetting and burning a gas mixture of a concentration is disposed along at least one second arrays of auxiliary burner ports for jetting and burning a gas mixture of a higher concentration. Main flames, which formed in the main burner ports, are stabilized with heat which they receive from auxiliary flames made by the auxiliary burner ports.
Generally, smaller burner ports will make more stable fire flames. There-fore, each prior art apparatus as shown in Gazette No. 1-47614 usually comprise a burner port assembly composed of a few metal plates corrugated and laid one on another to form between them an elongated opening. This opening is divided into a first array of small main burner ports arranged longitudinally of said assembly. However, nodes as idle portions not making any fire flame will inevitably intervene between main burner ports, so that some regions thereof disposed close to such nodes are spaced far from the auxiliary burner ports. As a result, the main flames being formed in main burner ports in such regions are not likely to be stabilized.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide an improved combustion apparatus that will stabilize combustion of a fuel gas.
In order to achieve this object, the present invention has employed the following improvements.
From a first aspect of the present invention, it provides a combustion apparatus with a burner port assembly that comprises an elongated first array of main burner ports for jetting and burning a fuel gas mixture of a concentration to make main flames. The combustion apparatus comprises also at least one second arrays of auxiliary burner ports for jetting and burning a further fuel gas mixture of a different concentration to make auxiliary flames, wherein the second arrays of said auxiliary burner ports extend along the first array of said main burner ports. The burner port assembly is constructed using inner and outer wall segments together with outermost wall segments or bands, wherein the inner and outer segments are corrugated to define between them openings serving as the main burner ports. The one of said band faces the corresponding one of said outermost segments so as to define between them collateral burner ports. A still further gas mixture to be jetted from and burnt at the collateral burner ports may either be of the same concentration as that for the auxiliary burner ports or of a medium concentration between said respective concentrations for the main and auxiliary burner ports.
Fire flames from such collateral burner ports will be formed adjacent to the basal portions of main flames, thereby stabilizing same to diminish the so-called problem of ‘lifting phenomenon’ during operation of the apparatus of the invention.
Such a stabilized combustion will be free from the phenomenon of flame pulsating, and scarcely emitting any noise. Almost complete and thorough combustion will be afforded to any rate of fuel gas fed to this apparatus, thereby diminishing the degree of incomplete burning of said fuel gas. Production of monoxide and any other toxic gases will now be reduced to a minimum, advantageously from an ecological point of view. Efficiency of energy is also improved for the fuel gas fed to this apparatus, thus enabling an accurate control of its quantity and rate.
As summarized above, the burner port assembly comprises the corrugated inner and outer segments together with the outermost bands. A space defined between the one corrugated outer segment and the corresponding outermost band facing it is herein divided into some discrete cavities, due to corrugation of said segment. These discrete cavities serve as collateral, burner ports having each a relatively small opening. In operation of the apparatus, significantly smaller but steady flames generated by the collateral burner ports will contribute to stabilization of the main flames as mentioned above.
The outermost bands incorporated into the apparatus of the invention give an addition to overall heat capacity of main burner ports. Therefore, even if occasionally heated by adjacent fire flames, the main burner ports would not be superheated to such a degree as possibly causing their thermal de-formation. By virtue of this feature, a higher ‘turndown ratio’ (T.D.R.) can now be adopted in this combustion apparatus.
From another aspect, the present invention provides a combustion apparatus with a burner port assembly that comprises an elongated first array of main burner ports for jetting and burning a fuel gas mixture of a concentration to make main flames. The combustion apparatus comprises also at least one second arrays of auxiliary burner ports for jetting and burning a further fuel gas mixture of a different concentration to make auxiliary flames, wherein the second arrays of said auxiliary burner ports extend along the first array of said main burner ports. The burner port assembly is constructed using inner and outer wall segments together with outermost wall segments or bands, wherein the inner and outer segments are corrugated to define between them openings serving as the main burner ports. The one of said outer segments faces the corresponding one of said outermost bands so as to define between them collateral burner ports. The second arrays of auxiliary burner ports comprise each a plate portion that cooperates with the corresponding one of outermost bands in order to define between them intermediate burner ports. A still further gas mixture to be jetted from and burnt at the collateral burner ports may either be of the same concentration as that for the auxiliary burner ports or of a medium concentration between said respective concentrations for the main and auxiliary burner ports. A yet still further gas mixture jetted from the intermediate burner ports is of another medium concentration between said respective concentrations for the main and auxiliary burner ports.
In this mode of the invention, the intermediate burner ports are provided between the outermost band constituting the first array of main burner ports and the plate portion as one of members constituting the second arralys of auxiliary burner ports. Therefore, at least three groups of fire flames made of respective gas mixtures of different concentrations will be generated in and along a broad central zone of the first array where the main burner ports are located close to the auxiliary burner ports.
In this case, fire flames from such collateral burner ports and intermediate burner ports will be formed adjacent to the basal portions of main flames, in addition to the flames from the auxiliary burner ports. Consequently, the main flames will be stabilized much
Akiyama Takashi
Hasegawa Takashi
Hata Hidenori
Iguchi Masahiro
Kameyama Shuji
Basichas Alfred
Noritz Corporation
Wood Phillips Katz Clark & Mortimer
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