Combustion apparatus

Abstract

A combustion apparatus has: a combustion housing; a partition plate provided in the combustion housing to partition a space in the combustion housing into a combustion chamber and an air supply chamber; and a plurality of rich-lean burners arranged in a right-left direction of the combustion chamber. A multiplicity of distributed holes are formed in the partition plate through which distributed holes secondary air is supplied from the air supply chamber to the combustion chamber. A flame rod facing to an upper side of a part of the rich-lean burners stops combustion when the flame rod does not detect any flames owing to a flame lift at a time of an oxygen deficiency. A supply quantity of the secondary air to the part of the rich-lean burners to which part the flame rod faces is larger than those to other parts.

Description

BACKGROUND OF THE INVENTION[0001]This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2010-127852, filed Jun. 3, 2010, which is incorporated by reference.FIELD OF THE INVENTION[0002]The present invention relates to a combustion apparatus equipped with a rich-lean burner and a flame rod for combustion stopping at the time of an oxygen deficiency.DESCRIPTION OF THE RELATED ART[0003]The following combustion apparatus has conventionally been known (see, for example, Japanese Patent Application Laid-Open Publication No. 2006-266516). That is, the combustion apparatus includes a combustion housing and a partition plate provided in the combustion housing to partition the space in the combustion housing into a combustion chamber and an air supply chamber on the lower side of the combustion chamber. The combustion apparatus further includes a plurality of rich-lean burners arranged in the right-left direction of the combustion chamber, and the combustion a...

AI Technical Summary

Benefits of technology

[0006]In view of the problem mentioned above, it is an advantage of the present invention to provide a combustion apparatus using rich-lean burners and being capable of surely stopping combustion before the worsening of combustibility owing to an oxygen deficiency.

[0007]In order to attain the object mentioned above, an aspect of the present invention is a combustion apparatus, comprising: a combustion housing; a partition plate provided in the combustion housing to partition a space in the combustion housing into a combustion chamber and an air supply chamber on a lower side of the combustion chamber; a plurality of rich-lean burners arranged in a right-left direction of the combustion chamber, each of the rich-lean burners including a burner main body elongated in a front-rear direction thereof, a lean flame port jetting out a lean mixture gas of a fuel concentration leaner than a theoretical air fuel ratio, and a couple of rich flame ports situated on both sides of the lean flame port in a right-left direction thereof to jet out a rich mixture gas of a fuel concentration richer than that of the lean mixture gas, the lean flame port and the rich flame ports being situated at an upper end of the burner main body; a multiplicity of distributed holes formed in the partition plate through which distributed holes secondary air is supplied from the air supply chamber to the combustion chamber; a flame rod facing to an upper side of a part of the rich-lean burners to stop combustion when the flame rod does not detect any flames owing to a flame lift at a time of an oxygen deficiency; wherein a supply quantity of the secondary air to the part of the rich-lean burners to which part the flame rod faces is larger than those to other parts.

[0008]Rich flames formed on the rich flame ports spread out to the outer sides to seek the secondary air at the time of an oxygen deficiency, here. Then, if the supply quantity of the secondary air is large, the rich flames are turned up from the outer sides by the secondary air blowing up to the outer sides of the rich flames. The rich flame ports on the outer sides in the burner main body are, furthermore, cooled by the secondary air, and the combustion velocity becomes slower. Consequently, the lifts of the rich flames become easier.

[0009]According to the present invention, the supply quantity of the secondary air to the part of the rich-lean burners to which part the flame rod faces is made to be larger than those to the other parts, and consequently not only the lean flame but also the rich flames lift at the initial stage of an oxygen deficiency in the installation part of the flame rod. The flame rod then falls in a state of not detecting any flames. Consequently, combustion can surely be stopped before the worsening of combustibility owing to the oxygen deficiency.

[0010]Now, it is also possible to provide a duct to lead the air in the air supply chamber to the part of the rich-lean burners to which part the flame rod faces for making the supply quantity of the part of the rich-lean burners to which part the flame rod faces larger than those to the other parts. However, this configuration needs the duct to increase the number of parts and to bring about an increase in cost.

[0011]Accordingly, in another aspect of the invention, it is preferable that the distributed holes in a part of the partition plate through which part the secondary air to flow to the part of the rich-lean burners to which part the flame rod faces passes are formed to have an opening area of the distributed holes per unit area of the partition plate larger than those of other parts. The supply quantity of the secondary air to the part of the rich-lean burners to which part the flame rod faces can hereby be made to be larger than those to the other parts without using any ducts, and the configuration is advantageous in order to decrease the number of parts to achieve the reduction of cost.

Problems solved by technology

Then, the flame lifts owing to the oxygen deficiency sometimes advance in a part in which no flame rod is provided owing to the distribution unevenness of a mixture gas and the like to bring about an incomplete combustion.

However, this configuration needs the duct to increase the number of parts and to bring about an increase in cost.

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