US2140088A - Liquid fuel burner - Google Patents

Description

Dec. 13,1938. A. MaCDONALD 2,140,088-

LIQUID FUEL BURNER Filed July 20, 1956 Inn/ ew .Y 157e/Zea; /Yd/zafd I 32* E' :'Ho'rrigy Patented Dec. 13, 1938 UNITED STAT ES PATENT OFFICE LIQUID FUEL BURNER Aeneas MacDonald, Evanston, Ill.

Application July 20, 1936, Serial No. 91,480

Claims. (Cl. 158-77) The invention relates to improvements in liquid bons and effect a .perfect chemical vand mechanifuel burners and more particularly to 'the type cal union of all combustible elements present. employing a substantially horizontally disposed Another object is nto provide a nozzle for a rotary atomizing cup having a novelly conliquid `fuel burner .Withmeansto direct a stream structed primary air nozzle arranged to discharge of primary air angularly intothe `liquid fuel 5 into a fire box a thoroughly atomized liquid fuel stream to effectively mix said fuel and air, and spray in a manner to effect thorough combustion direct the atomized fuel in any angular direcof all hydro-carbons in suspension. tion relative to the axisof the burner.

Liquid fuel burners of the general type illus- Another object is to provide a fire box for trated herein commonly include rotating means liquid fuel with an inclined grate having a'plu- 10.

to discharge, under pressure, oil or other fuel rality-of secondaryairpassages thereinarranged into a fire box in a substantially straight tubular to insure an adequate supply of fresh air .to the stream of fuel completely venclosed in a tubular flame at points required to insure perfect com- Wall of air discharged under pressure inthe same bustion.

direction as the liquid fuel. Such an arrange- Another Objectis .to provide aliquid fuelburner 15' ment prevents rather than assiststhorough miX- With mechanal vund 10W 'Pressure air 'means t0 ing of the air With the Vfuel .prior to said stream effect atomization of liquid fuel, including an being broken up by striking the refractory back atomizing CUD and @Onl'fllled means v1"01 COH- wall of the fire box or a baflie, with the result trolling the angle 0f iling- 2o that localized Vtemperatures are in evidence. 'Ihis Anotherobject is :tofprOVde 2 liquid lll bul'h'fl' 20 manner of attempted atomization and burning with means to controlathe direction of rc in all of liquid fuel is highly ubjecticnai because directions, upwardly, AdOWnWardlr 0r Sidewise. much of the heat that is generated is lost, the `Another object iS 130 provide meahS t0 IJIOduCc refractory material is burned outandalsc due t0 a substantially flat flame withinthe fire box and the incomplete atomization of the liquid fuel, an directit in such a direction as to insure `complete 25-L excessive amount of carbon accumulates Within Combustion of all fuel Supplied thereto Without the re box to further minimize the effective mphglnglsaid fuel against-.lille 1`b0X Walls 01 heating. baffles therein.

With the ordinary type of burner there also is Another object istcprovide a liquid fuclburncr no known means provided to insure mixing of With means .t0 effect 'angle lng t0 DIOdU-Ce a 3o secondary air entering the fire box through the llame that Will burn in suspension andhave fOr grates, with the result that a wall of cool air its guidance a :bed or strata of secondary all" insulates the fire box Walls and other parts from Which forms a Cushion between the 1:1001 and the heat 0f the name, grate of the -re Vbox and the `name, and thereby :1.3 It is ytherefore an object of the invention to effect Complete mXing Of'ar andhydro-carbons 3:, A

provide the Combination of a noveuy Constructed to `insure :perfect fuel .combustion with little or liquid fuel burner and a novel re -box Structure no 105s of .heat and fno eXCeSS'OfLCOOl alfto prevent cold air from entering the fire box The foregoing and Such 0131er ObJ'eC'GS 0f the and insulating the Walls and other parts thereof invention as 'Wm become apparent henafte Another object is to provide means to insure undrstood from apelllsal 0f the OllGWiIlg Specicomplete combustion of the -hydro-carbons in full cal'lfon l'efelfencebeing had t0 the aCCOHlDaIlY- suspension, 4thus minimizing operation and fuel Img drawlngfm which: Costs and rendering unnecessary the frequent re Fig. 1 1s a fragmentary vertical sectional view pairs to the refractory now occasioned with through 'the'r box qflheatmgvplant Slimwng 45 known types of burnerspartly in elevation, .a liquidfuel burnerassociated Another Object is to provide a liquid fue] burner therewith embodying 'features orY the invention.

Fig. Zisan enlarged fragmentary longitudinal 0f the type havmg a Total-mg fuel atomlzmg Cup sectional View through :the discharge end of the 5( ywith a novelly constructednozzle for effecting liquid fuel burner .Showninpig 1 50 a very 1nt1mate mixtureof a1r and hydro-carbon. Fig 3 is a, perspective `of one formcf improved Another object is to provide the -re boxvvith nozzle, a secondary air inlet suitably arranged With Fig. 4 is a vertical sectional view through .a

respect to the liquid fuel -and primary air inlet nozzle embodying modified features of constructo msure complete mixing of airand hydro-cartion. Y A55 against the heat Within the box as the description proceeds, `Will be more readily ic- Fig. 5 is a front end elevational view of another form of nozzle.

Referring particularly to Figs. 1 to 3, inclusive,Y the liquid fuel burner, indicated generally at II, preferably is mounted in a tilted position over the flre door opening I2 in one wall. I3 of a V flre box I4, with its nozzle I5 extending through the opening I2Y substantially as shown. A flanged collar I6 preferably is carried on the rear end of the nozzle I5 so that, if advisable, the yopening I2, around said nozzle', can be tightly sealed. However, it is desirable that the collar I6 have suitable openings therein which may be closed by a rotatable ring 20 mounted on the collar. The ring 20 has aligned openings so that, when in open position, air can enter the fire door opening around the nozzle I5 to prevent overheating of said nozzle.

The flre box I4 may be of any conventional size or shape adapted for use with liquid fuel burners and preferably has an inclined grate II provided with a plurality of air passageways I8. The passageways I8 preferably are arranged horizontally in checker board fashion with the maximum number of passages at the lower end, all of which may be wholly or partially closed by a suitable closure I9 preferably mounted over the front wall of the flre box whereby the volume of air admitted through the grate may be con- ,trolled casing 2| and has an atomizing cup 25 flxedly secured on its end, which, as best shown in Fig. 2, is axially positioned within a sleeve 26 extending inwardly from the discharge opening of the nozzle I5. Liquid fuel is supplied to the rear end portion 2l of the atomizing cup through a suitable conduit 28 and is entrained by the air stream created by ejector 22, through ports 29 into forward end portion 3l of said cup from where it is radially ejected into the fire box-substantially in the manner indicated by the broken lines.

In known types of liquid fuel burners, having conventional types of nozzles thereon, the liquid fuel is dischargedfrom the rotating atomizing cup in a substantially straight stream horizontally into the fire'box and a circular wall of primary air, passing out of the annular clearance between the rotating cup 25 and the nozzle opening, surrounds said stream and effectively prevents complete atomization and mixing of the primary air with the hydro-carbons in the fuel.

To avoid this inefficient atomization and unsatisfactory partial combustion of the fuel, the improved nozzle I5 has at least one enlargement providing an auxiliary primary air passageway 32 preferably disposed above the fuel stream. As shown, the passageway 32 communicates with the interior of the nozzle and air flowing through said nozzle is broken up by the sleeve 26 so that some of said air flows through the annular opening between theV atomizer and the sleeve 26 and the remainder ilows through down of the fuel directs the flame downwardly angularly substantially parallel to the plane of the inclined grate II, as shown in Fig. 1. The flame however does not strike the refractory of the grate I1 or the floor due to a cushioning layer of secondary air flowing over the grate through passageways I8.

Obviously much of this incoming secondary air striking the fuel stream substantially yat right angles is projected directly into said stream, thus increasing the atomization of the fuel to permit complete combustion. The arrangement shown also insures the introduction of a larger amount of secondary air at the upper portion of the grate because of the shorter air passageways I8. Inasmuch as the flame does not strike any of the refractory material lining of the re box, said material is not destroyed nor is its efficiency impaired in any manner by the accumulation of carbon thereon. It is obvious also that the nozzle I5 may be turned into any desired position for directing the flame angularly upwardly, downwardly or to either side thereby adapting the nozzle for use on burners installed in various types of fire boxes.

The modified form of nozzle I5, shown in Fig. 4, is similar to that previously described except that this nozzle has two auxiliary primary air passageways 32, one of which for the purpose of illustration is shown closed by a suitable cap 33. The other primary air passageway has a curved sleeve extension 34 mounted on its end for adjustment whereby the point of intersection of the air ejected therefrom and the fuel stream may be varied to suit various types of installations. The auxiliary air passageways 32a each may be closed by a suitable butterfly valve 35 in lieu of the cap 33. It is apparent that three or even four auxiliary primary air passageways can be provided on the nozzle and that one or more of said passageways may be fitted with adjustableextensions 34 and the remaining passageways closed either by a cap 33 or a butterfly valve 35. Use of this form of nozzle readily adapts a liquid fuel burner for use in any known type of combustion chamber wherein it may be necessary to direct the flame angularly upwardly, downwardly, or sidewisle or at any Yanglle between the horizontal and vertical by opening the proper air passageway or passageways.

The nozzle shown in Fig. 5 differs from the previously discussed forms in that the outlet opening Vof the Vauxiliary air passageway V32b preferably is crescent shaped to discharge a heavy stream of primary air onto the top side of the fuel stream and a relatively light stream against the sides Vof said stream. This form of opening is more effective to knock down the sides of the fuel stream which, because of the rotation of the atomizer, might not be encountered by an air stream discharged from a nozzle of the type shown in Figs. 2 and 3.

The arrangements provided herein are such that a down-shot completely atomized highly volatile fuel mixture is delivered into the flre box for complete consumption of all the hydrocarbon therein without the necessity of directing the fuel blast, as formerly, against the refractory or bames which resulted in damage to said refractory or bailies, inefficient localized heating and high cost operation.

Although exemplary embodiments of the improved nozzle and flre box ,have been illustrated in the accompanying drawing and described in detail in the-foregoing specification, it is to be 2,14o,oss

clearly understood that the invention is capable of embodying various modications in structural detail and that the improved burner nozzle is readily applicable to any known type of fire box and most conventional types of burners whether they use a rotary atomizer or not, and it is, therefore, not desired to limit the invention to the precise structures illustrated but to embody such modifications as fall within the spirit of the invention and the scope of the appended claims.

I claim:

l. In combination with a furnace having a re box comprising an inclined grate provided with air admission openings, a liquid fuel burner including a blower and a rotary fuel atomizer for delivering an atomized fuel stream over said grate and into said fire box for ignition, and a nozzle on said burner including at least one angular-ly disposed air outlet for delivering an air stream angularly against the fuel stream to deflect said fuel stream toward said inclined grate.

2. In combination with a furnace having a fire box, an inclined grate in said fire box having a plurality of air passageways extending therethrough, a liquid fuel burner including a blower and a rotatable fuel atomizer for discharging an atomized fuel stream into said re box, and adjustable means on said burner adapted to direct an air stream angularly against said fuel stream to deflect said fuel stream toward said grate.

3. In a furnace for burning liquid fuel, the combination of, a fire box including a front wall and a grate, a liquid fuel burner including a rotary fuel atomizer mounted in the front wall,

a nozzle on said burner for delivering a stream of air and fuel into said re box above said grate, a spout on said nozzle having an air passageway for directing air downwardly angularly against the upper side of the stream to deflect said stream toward said grate, and said grate having a plurality of openings to deliver air against the lower side of said deiiected stream in progressively decreasing amounts as the fuel moves across the top of said grate.

4l. In combination with a furnace having a re box provided with an inclined grate in one wall thereof, a liquid fuel burner including a blower and a rotary fuel atomizer for delivering an atomized fuel stream into said re box for ignition, a nozzle on said burner surrounding said atomizer, said nozzle having a restricted discharge end to permit passage of a tubular column of air` around said atomizer, and a spout communicating with the interior of the nozzle, said spout having an air outlet of substantially the same width as the diameter of the discharge end of said nozzle directed angularly towards said discharge end.

5. A furnace including a re box having a front wall provided with an opening, a liquid fuel burner arranged to discharge a fuel stream through said opening, a oor in said fire box inclined downwardly rearwardly from a point just below the opening in said front wall, and means on said burner to direct an airstream angularly against the fuel stream for deecting said fuel stream towards the oor, said floor having a plurality of passageways therethrough of different lengths to admit atmospheric air into said fire box below said fuel stream.

AENEAS MACDONALD.

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