US2834405A - Flame retention means for gas burners - Google Patents

Description

May 13, 1958 T. s. VOORHEIS FLAME RETENTION MEANS FOR GAS BURNERS Filed Oct. 22. 1954 INVENTOR- TEMPLE SVoomms BY WYVQPWLCQ\ &

A'vvoranzvs a R United States Patent r Patented May 1*3, 195.8

FLAME RETENTION MEANS FOR GAS BURNERS Temple S. Voorheis, San Francisco, Calif. Application October 22, 1954, SerialNo. 463,922 .1 Claim. c1. 158-7) baflles, in themanner briefly above mentioned, establishes a plurality of riflles within the air stream which induce and create desired .eddy currents ofmixed gas and air. These eddy currents, in turn, establish relatively ,quiet zones of combustible mixture in which stable combustion can occur, and which function to retain or anchor :the flame front within the combustion chamber.

A principal object, therefore, of the present invention is to provide novel means of the character above briefly mentioned and which functionto induce and insure retention of the flame front within a gas burner combustion chamber.

'Other numerous objectsand advantages of the present invention .will become apparent upon reading'the followingspecification and referring to the accompanying drawings in which similar characters of reference represent cor-responding parts in each of the several views.

3 In--the drawings:

Eig; 1 .isan enlarged fragmentary longitudinal sectional view of a burner unit incorporating an embodi- -ment .of the invention as a component part thereof.

the chamber, and'the nature and composition of the continuous flow .or stream of the combined gas and air mixture into the chamber. In this latter regard, it is imrportant to-the maintenance. of stable flame conditions of'forced draft. type burners to provide eddy currents or. quiet-zones. of. combustible .mixture to anchor. the fiame front. ..More specifically, it is desirable to maintain eddy currents in the combustion chamber, and particularly adjacent the throat opening thereof, in order to reduce the danger of explosion that might result should the velocity of the air draft into the combustion chamber exceed the rate of propagation of the flame, in which case the flame front would be blown out into the furnace with resultant loss of ignition within the combustion chamber.

The problem of insuring flame retention in the combustion chamber is greater, generally speaking, in the more modern furnaces which characteristically comprise greater heat exchange areas and relatively less refractory surface areas than older types of furnaces. In short, the tendency in recent years has been toward making furnaces with less refractory surface area and with a greater black or heat exchange area than previously regarded as feasible and, this, in turn, accounts for the fact that more modern furnaces are, generally speaking, comparatively cooler than their predecessor counterparts. It is also generally true that the cooler the furnace temperature, the more difficult becomes the problem of maintaining safe and stable conditions of combustion, and hence the more important becomes the reason for providing means that will induce and insure retention of the flame front within the combustion chamber.

In general, the present invention which is illustrated in the drawings which will be described hereinafter in greater detail, comprises, in combination with a gas burner of the type incorporating a combustion chamber and a source of forced air draft to the chamber, an annular gas supply ring or pipe disposed adjacent the throat opening to the chamber between the air source and said chamber. The gas ring is formed with a plurality of gas jet openings spaced circumferentially around the inner periphery of the ring, and a plurality of bafiles are provided which are also spaced around the inner circumference of the ring between the jet openings and the air source so as to project into the path of forced draft air flowing through the ring into the combustion chamber. As will more fully appear hereinafter, the arrangement of the Fig. 2 is, an enlarged fragmentary view. partiallyin section taken substantially on line 2-2 of Fig. l.

-Fig. 3-is an enlarged fragmentary view in front ele-' vationof'the gas ring unit viewed substantially in the plane of reference line 3-3 of Fig. 1.

Referring now more particularly to the drawings, the

1 gas burner unit therein illustrated is shown as comprising generally a-burner housing A, an air register'B, a gas supply-ring Cand a combustion chamber D.

The construction and operation of the burner .unit-may :be considered more or less conventional and, in general,

air from the wind :box. indicated fragmentarily at-10,is directed into chamber D through the louvre type air register heretofore indicated generally at B. Gas is supplied via conduit 12 to ring C and combustion takes place, of course, in combustion chamber D.

Figs. 1, 2 and 3 illustrate an embodiment of the invention in which the specific arrangement of baflles 13- are shown in conjunction with a preferred type of gas ring assembly in which the gas jet openings are arranged in circumferentially spaced echelon groups indicated at 14 This preferred echelon grouping of the jet openings is specifically disclosed and claimed in my copending application filed concurrently herewith and entitled Gas Burner Ring Construction. It will suflice to remark herein that the primary purpose of arranging the gas jet openings in echelon formation as shown is to insure more rapid, thorough, and efficient mixing between air and gas in burner units of the type illustrated and in which the air is directed into the combustion chamber from a louvre type air register in a generally spiral or swirling motion. In short, the gas jet openings are arranged in echelon in which the lines of bearings (indicated by reference line RR) of the echelon groups are all disposed parallel to one another but at an oblique angle relative to the axis of opening into the chamber, this being the angle at which the swirling air stream enters the chamber. As explained in my said copending application, the arrangement of the gas jet openings in echelon formation and on lines of bearing corresponding to the directional path of the air stream prevents screening of the air which, in turn, results in several advantages including better mixing between gas and air, reduction in air draft loss due to the screening of the air' by the gas streams, and attainment of a more uniform flow of air to the combustion chamber.

In the specific echelon grouping of jet openings disclosed in my said copending application and in the accompanying drawings, each echelon group 14 is disposed at approximately 15 angular displacement with respect to the medial axis of opening M--M of the combustion chamber and with respect to the diametral plane of the gas ring C. It is appreciated, of course, that the specific angular displacement between the echelon groups and the axis opening to the combustion chamber might vary substantially between various gas burner units in view of the fact that the angular bearing of the echelon groups 14 is made equal to the angle at which the forced draft air stream is directed into the combustion chamber from the particular type of louvre type air register utilized to control the air flow.

In the specific bafi le arrangement shown in Figs. 1, 2 and 3, each of the baffies is formed in the nature of a rhomboid and with its parallel end surfaces 16 disposed parallel to the lines of bearings of the echelon groups of jet openings 14 It is further observed that the spacing and arrangement of the baffles is such that one bafile is interposed between each said echelon group and the discharge end of the air register B. In short, the spacings between the baffies are in registry with the spacings between adjacent echelon groups of jet openings 14*, although the distance or spacing between adjacent bafiles is preferably made substantially less and preferably about one-third of the distance or spacing between adjacent echelon groups 14 In operation, the swirling air from the air register in flowing over and around the end surfaces 16 and the top surfaces 17 of the baffles will result in formation of eddy currents which, in turn, establish relatively quiet zones of combustible mixture of gas and air which, as already explained, insures retention of the flame front within the combustion chamber.

Although the present invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be practiced within the spirit of the invention as limited only by the scope of the claim appended hereto.

I claim:

In a gas burner unit of the type having a combustion chamber, a forced draft air source for introducing air to said combustion chamber in a generally swirling motion disposed at an oblique angle relative to the medial axis of the said chamber, an annular gas pipe disposed adjacent the throat opening to said chamber between said chamber and said source through which air from said source passes into said chamber, a plurality of jet openings arranged in circumferentially spaced echelon groups around the inner circumference of said annular gas pipe with said echelon groups disposed along lines of hearing substantially paralleling the said oblique angle at which the swirling air enters said chamber, the improvement comprising: a plurality of bafiles spaced circumferentially around the inner circumference of said gas pipe and projecting therefrom generally toward the center of said ring and into the path of swirling air flow from said source to said chamber; each said bafile disposed adjacent a respectively associated echelon group of jet openings and also disposed between and in approximate alignment with a said echelon group and said source to create eddy currents of mixed gas and air flowing into said combustion chamber; each baffle formed substantially rhomboidal in shape defining parallel end surfaces each lying within a plane extending parallel to the said oblique angle at which the swirling air flow enters said chamber.

References Cited in the file of this patent UNITED STATES PATENTS

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