Inshot burner flame retainer

Abstract

A flame retainer for an inshot burner has a plurality of secondary openings that take full advantage of the space available to limit their size in one dimension to prevent flashbacks but are sufficient in size to allow for the flow of sufficient primary air so as to prevent yellow tipping and soot formation. The slots are elongated in radially cross-sectional shape, and their widths are limited to a dimension of 0.13 inches. The width is also limited to dimensions equal to or greater than 0.09 inches so as to prevent the formation of soot.

Description

TECHNICAL FIELD [0001] This invention relates generally to residential furnaces and, more particularly, to inshot burners with flame retainers. BACKGROUND OF THE INVENTION [0002] Gas fired appliances, such as residential and light commercial heating furnaces, often use a particular type of gas burner commonly referred to as an inshot burner. In this type of burner, fuel gas under pressure passes through a central port disposed at the inlet of a venturi burner nozzle. Atmospheric air is drawn into the burner nozzle and mixes with the fuel gas as it passes through the burner nozzle. In some constructions, a burner head insert, also referred to as a flame retention insert, made of compressed sintered or powdered metal is mounted in the outlet end of the tube. In operation, as gas is injected into the inlet end of the nozzle, it entrains air into the nozzle. This primary air / gas mix flows through the nozzle to the burner head insert. The primary air / gas mix passes through outlet opening...

AI Technical Summary

Benefits of technology

[0008] According to another embodiment of the invention, the passages are formed such that in radial cross section, they are annular in form and are circumferentially equally spaced around a central opening. The restricted radial width prevents flashback, while the circumferential length is sufficient to prevent sooting.

Problems solved by technology

Some of the problems associated with conventional inshot burner designs are improper ignition, flame instability, noise and nitrogen oxides formation.

Ignition problems can arise when the ignition location is critical.

Flame liftoff is a major cause of the noise associated with the operation of inshot burner nozzles.

This condition can cause overheating and deterioration of the nozzle.

While such designs are helpful in addressing the problems discussed hereinabove, they do not adequately address the problem of flashback and the propensity for producing soot, particularly when using propane rather than natural gas as the fuel.

However, when dealing with other design limitations on the overall size of the burner, simply downsizing the perimeter passages results in insufficient primary air for combustion.

That is, as the size of the passages is reduced to prevent flashback, there is a tendency to cause a yellowing of the flame tip which, in turn, tends to cause the formation of soot.

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