US2854068A - Nozzle for gas burners - Google Patents

Description

United States Patent() NOZZLE FOR GAS'B'URNERS Charles D. Jones, Mission Hills,.Kaus., assignor to Siemon Manufacturing Company, Grandview, Mo., a corporation of Missouri Application Uctober 17, 1955, Serial No. 540,663

1 Claim. (Cl. 158-113) This invention relates to new and useful improvements in gas burners, and has particular reference to the nozzles of gas burners utilizing a'forced draft air supply.

The principal object of the present invention is the provision of a gas burner nozzle to which both the gas and the air supply are furnished without prior mixing, and which is adapted in a novel manner to provide an extremely thorough intermixture of the air and gas at and directly in front of the nozzle. The main purpose of such a thorough intermixture is of course eicient and total combustion, but the arrangement shown has other valuable functions. Firstly, it does away with the necessity of a primary mixture of `air and gas prior to delivery to the nozzle, and eliminates the bulky and expensive venturi, aspirators, and mixing chambers often necessary for this purpose. Secondly, it provides good llame retention characteristics; that is, the air-gas mixture is ignited and burns form the face of the burner, rather than traveling a substantial distance ahead of the burner before igniting. This ilame separation is believed due to the fact that in burners heretofore made the mixing occurring at the nozzle itself is so incomplete that a certain travel is necessary before the mixture reaches combustible proportions. Flame separation -is usually :accompanied by imperfect and ineicient combustion. Good flame retention also provides a much quieter burner, greatly reducing the loud roaring noise usually associated with forced-draft gas equipment, reduces any danger that the burner might blow itself out, and eliminates pulsation, which occurs when the ame alternately separates -from and returns to the burner. Pulsation produces highly objectionable noises and vibration, and also reduces combustion eiciency. With the efficient combustion produced by the burner forming the subject matter of my invention, it will be apparent that a greatly increased amount of gas may be burned eiciently as compared to other burners of comparable size, and that the rating thereof may be correspondingly increased.

Other objects are extreme simplicity and economy of construction, efficiency and dependability of operation, and adaptability for use in a wide variety of burner applications.

With these objects in view, as -well as other objects which will appear in the course of the specification, reference will be had to the drawing, wherein:

Fig. 1 is a longitudinal sectional view of the delivery end portion of a gas burner including a nozzle embodying the present invention, taken on line l-I of Fig. 2,

Fig. -2 is a sectional view taken on line lI-II of Fig. l, and

Fig. 3 is a sectional view taken on line AII-I--I'IYI of Fig. l.

Like reference numerals apply to similar parts throughout the several views, and the numeral 2 applies to a blast tube which may be of any convenient cross-sectional shape, the forward end of which is customarily seated in the wall of a furnace combustion chamber so as to communicate therewith, and through which air is delivered forwardly, as indicated by arrows 4, by any suitable 2,854,058 Patented Sept. 30, 1958 rcethrough which `gas flows forwardly as indicated by arrow' 8. An insert 10 of refractory material is carried in the forward end of blast tube 2, and a large tubular orifice 1'2l isformed axially therethrough and concentrically with gas tube Orifice 12 is frus'to-conical, being of larger diam-` eter at its outer end than at its inner end, for a purpose to -be described below. Gas tube 6 terminates within oriiice 12.

The nozzle 14 forming the subject matter of this invention comprises a cap 16 screwed over the forward end of gas tube 6, and a forwardly opening circular cup-shaped dellector plate 18 secured to the forward end of said cap in coaxial relation with gas tube 6 by means -of screw 20. The forward end of cap 16 is conically tapered behind the deilector plate, `and has a plurality of holes 22 formed therethrough in equally spaced relation about the periphery thereof. These holes communicate with the interior of the cap and thence with tube 6, and are inclined in forwardly divergent relation as shown. Dellector plate 18 has a ring of holes 24 formed therethrough :adjacent the lip thereof, said ring being concentric with the plate.

In operation, air and gas in the proper proportions for correct combustion `are fed respectively to tubes 2 and 6, and ow forwardly therethrough. The blower and regula-ting equipment for `accomplishing this is well known in the art, and in and of itself forms no part of the present invention. It will be understood also that the burner may be provided with the usual pilot light and safety devices.

Gas emerging from holes 22` in cap 16 substantially blankets the rearward face of deflector plate 18, and largely prevents air from passing forwardly through holes 24 `of said deflector plate. At the same time, air passing forwardly past the lip of the deflector plate, due to its relatively high velocity, for-ms a sheath around said deflector plate which in a large measure prevents gas from being directed outwardly past the rim of the deflector. Instead, the gas passes forwardly through holes 24, as will appear.

As the high-velocity air passes forwardly around the lip of the deflector, it creates an aspirator action which forms a zone of sharply reduced pressure directly ahead of the deector plate. Air rushing in to iill the partial vacuum thus formed creates a high degree of turbulence in this zone, and the partial vacuum also serves to draw gas forwardly through holes 24 into the turbulence which exists forwardly of the deector. This turbulence mixes the air and gas with great thoroughness, so that when ignited it will burn at or directly adjacent the deector plate. tEven with extremely high flow rates, the flame has been found to start at least before the mixture reaches the forward face of insert 10. The conical shape of orifice 12 also functions to cause .a pressure reduction in the forward end portion thereof, which contributes to still greater turbulence and hence to still greater thoroughness ness of mixture.

The theory of operation set forth above is believed correct, although due to the nature of the invention it is virtually impossible in any practical way to trace the precise course and behavior of the air and gas in and adjacent the nozzle. However, the structure shown has been exhaustively tested, as well as numerous variations thereof, and has been in commercial production and usage for several months. It definitely possesses all of the desirable end results above enumerated.

Although I have shown and described a specific embodiment yof my invention, it will be apparent that many minor changes of structure `and operation could be made without departing from the spirit of the invention as dened by the scope ofthe appended claim.

What I claim as new and desire to protect by Letters Patent is:

With a gas burner having .a blast tube open at its forward end, means for delivering air forwardly through said blast tube, and a gas supply -tube extendingv longitudinally through said blast tube, the `coml'nation of a nozzle comprising a cap secured to and closing the for- Ward end of said gas tube and having a plurality of apertures formed therein, and a generally spherically cupshaped deector plate secured to said cap, said plate opening forwardly and being disposed coaxially with said gas tube, and having apertures formed therethrough, said cap apertures being positioned to direct streams of gas in forwardly divergent relation over the rearward face of said detlector plate, substantially tangent to the curvature of said plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,604,525 Lynskey Oct. 26, 1926 2,697,032 Jones Dec. 14, 1954 2,762,428 Blaha Sept. 11, 1956

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