US1920460A - Fluid fuel burner - Google Patents

Description

ug. l, 1933. R. F. BRUNS FLUID FUEL BURNER Filed OCT.. 19, 1931 awww/Hoz m R B E R Patentedl Aug. 1, 1933 l .UNITED STATES PATENT OFFICE FLUID FUEL BURNER i Robert F. Bruns, Sarpy County, Nebr.

Application October 19, 1931.l Serial No. 569,705

2 Claims. (Cl. 158-28) My invention relates to burners for fluid said hub 11 and resting upon the bottom of the fuels, such as gas and oil, wherein the fuel is dedraft-tube, and a pair of collar-portions 14 arlivered from a nozzle into a stream of air moving ranged symmetrically at opposite sides of the axially of the nozzle, and wherein the fuel is hub above the fuel-pipe. The collar-portions mixed with the air, ignited and burned in a zone 14 are kerfed and provided at the kerfs with 50 adjacent to the nozzle. It is the object of my clamp-screws 15 for holding therein the insulatinvention to provide, for burners of the foregoing-sleeves 16 which surround the stem-portions ing character, a combined electrical ignition 17 of the ignition-electrodes. Said stems 17 are and air-directing device whereby the ignition parallel with each other, being held by the supl electrodes may be positioned outside the path of port and the insulating sleeves 16 in positions 65 the fuel emerging from the nozzle, and the arc intermediate the fuel-pipe and the sides of the 0r succession of sparks which pass between the draft-tube, at a level above the fuel-pipe and electrodes be carried by a deiiected portion of the nozzle. To the outer or front end 0f the the air-stream into the path of the fuel to igstems 1'7 are connected suitably insulated connite the same. A further object is to provide ductors 18 which are extended through the 70 means for effecting a whirling or twisting motion draft-tube alongside the fuel-pipe to connect of the peripheral portion of the air-stream withwith the coil, transformer or other source of out interfering with the directing of that part high-tension Current emplOI/'ed f01` the ignitionof the air-stream which carries the ignition arc The rear end of one of the electrodes is curved 20 into contact with the fuel. laterally as shown in Fig. l, and slightly down- In the accompanying drawing Fig. 1 is a plan ward as shown in Fig. 2, so that the end of the view of devices embodying my invention, the electrode is above and extends slightly beyond associated draft-tube being in horizontal section, the end Of the DOZZle, Said end 0f the eleCtlOde Fig. 2 is a side view, the draft-tube being in verhaving a flat horizontal terminal edge 19 extical section, and Fig. 3 is an end view of the tending transversely t0 the aXiS 0f the HOZZle 80 device. and draft-tube. The rear end portion of the In the illustrated embodiment of my invention other electrode is bent laterally, substantially at the same is applied to an oil burner wherein the a Tight angle aS SllOWn in Fig- 1, tO eXtend fuel-nozzle 5 is Carried at the end of a pipe 6 transversely in spaced relation to the end 19 of through which the oil is supplied under pres the first electrode, the transverse terminal porsure, the nozzle having at the end thereof a, tion being flattened to form a substantially recsmall central aperture through which the fuel tanglllal" plate 20 Which iS inCliIled, aS ShOWIl in emerges in e, conical Spray, The fueppipo eX- Fig. 2, so that its lower edge is rearward of its tends longitudinally within a much larger pipe upper edge 90 or draft-tube 7, through which the air is Sup- In the operation of the described burner, the plied for supporting combustion of the fuel, the fuel is sprayed from the nozzle in a conical forair usually being under forced draft, being immatlOn, aS indicated in Fig. 2, and the Outer pelled by a fan or bloweisuch as is Commonly portion of the air-stream through the draftemployed in this art. The draft-tube is extendtube ls given a Whll'llng 01' tWlStlng motion by 95 ed through the wall 3 of o, furnace to the comthe helical ribs 10 in the annular space `about bustion-chamber thereof, said tube terminating the mouth 0f Said tube- The Central pOltlOn 0f at or near the inner side of said wall, and the the alt-Stream tends t0 InOVe along Paths Sub' fuel-pipe being arranged so that the nozzle 5 is Stantally parallel With the eXiS 0f the nOZZle, near the end of the drafttubo but does not but at the end of the nozzle the air-stream forms project therefrom, an eddy about the transverse end-surface there- Preferably, there is disposed within the rear 0f, and the feel-jet or spray also tends to enor inner end of the draft-tube a sleeve 9 having train and dmW lOOTtlOnS 0 the all' 1n tOWafd foi-med integrally therewith a plurality 0f he1 the axis thereof. iThe flat transversely extend- 5 cal ribs 10 adapted to @auge o, whining motion ing inclined terminal-plate 2() intercepts a porof the air-stream emerging thciefrom. Within tion 0f the air-Stream and dlleCtS the Same the draft-tube, and spaced forwardly or outdownwardly tOWind the Spray-0ne 0f tl1e fuel, Wardly from the end ofthe Sleeve 9y is a Supand said deflected portion of the air-stream port comprisingr a hub-portion 11 tting upon passes between said plate 20 and the terminal the fue1 pipe and secured thereto by a Screw 12y edge 19 of the other electrode. Said deflected a leg-portion 13 extending downwardly from portion of the air-stream causes the arc, o1 succession of sparks passing between the terminals 19 and 20, to assume a U-shaped formation, bowing downwardly from the terminals and contacting with the spray-cone of the fuel to effectively ignite the same. The gap or distance between the terminals 19 and 20 is so proportioned that the initial spark or electrical discharge is readily formed between the same, and the potential of the ignition-current employed is such that after the initial discharge or breakdown of the gap the path of the alternating arc or series of sparks passing between the electrodes may be greatly elongated and assume the deeply bowed U-formation represented in Fig. 2, before disruption of the arc will occur.

It will be seen that by the described structure the ignition electrodes are relatively distant from the path of the fuel and cannot contact with or become fouled thereby, or accumulate carbon deposits which might short-circuit and render the same inoperative. The Wide endface 19 of the one electrode and the plate 20 of the opposed electrode afford relatively large areas-between which the ignition arc may pass, so that pitting or erosion of a portion of the surface will not alter the width of the gap as a whole nor prevent normal continuation of the ignition.

In burners of this class it appears to be necessary, or highly desirable, to provide means for producing a whirling or twisting motion of the main body of the air-stream emerging from the draft-tube about the fuel-nozzle, such motion of the air-stream causing a more rapid and effective mixing of the air and fuel, and greatly reducing the roaring noise caused during operation of the burner. The usual means for producing the twisting movement of the air-stream, comprises helicoidal blades or vanes positioned within the draft-tube forwardly of the fuelnozzle and relatively distant from the end or mouth of the draft-tube, so that all of the air passing the nozzle is disturbed and deflected by such air-directing means. In my improved structure, the helical ribs 10 on the sleeve 9 in the mouth of the draft-tube, produce the desired whirling motion of the air and quiet operation of the burner, although said ribs aifect directly only the outer or peripheral portion of the airstream, and thus avoid interference with the directing of the central portion of the air-stream to produce the desired bowed formation of the ignition arc.

Now, having described my invention, what I claim and desire to secure by Letters Patent is:

1. In a uid fuel burner, the combination with a fuel-nozzle adapted to deliver a jet of fuel, and a draft-tube surrounding said nozzle and adapted to direct an air-stream longitudinally past the same; of ignition-electrodes disposed adjacent to said nozzle and having wide terminal portions spaced apart longitudinally of the draft tube and extending transversely thereof, the forward of said transverse terminal portions having a face at the gap between the electrodes inclined to the draft-tube axis, and said inclined face being positioned to deflect a portion of the air-stream through the gap and toward the fueljet, for the purpose set forth.

2. In a fluid fuel burner, the combination wit a draft-tube provided at the discharge mouth thereof with annularlyl arranged helical air-directing means, and a fuel-nozzle arranged centrally of said mouth in spaced relation to said air-directing means; of ignition-electrodes disposed adjacent to said nozzle and having wide terminal portions spaced apart longitudinally of the draft-tube to provide a gap between them, the forward of said terminal portions being shaped and arranged to direct air through said gap toward the orifice of the nozzle.

ROBERT F. BRUNS.

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