US2595759A - Atomizing nozzle for spraying viscous liquids - Google Patents

Description

y 6, T952 B- o. BUCKLAND ETAL 2,595,759

ATOMIZING NOZZLE FOR SPRAYING VISCOUS LIQUIDS 2 SHEETSSHEET 1 Filed Nov. 50, 1948 Fig.2.

lnvenfors'. Bruc O. Buckland, Donald C. Berkeg, by W Their Attorney.

y 1952 B. o. BUCKLAND ET AL 2,595,759

ATOMIZING NOZZLE FOR SPRAYING VISCOUS uquzns Filed Nov. 30, 1948 2 SHEETSSHEET 2 Fig.4. Fig.5. 53 7" Z 7 M W fl/ou I (/0 is m4 is M5 M5 lnvenTors Bruce 0. Buckland,

Donald C. Berke 3 WW Their Aflornqg- Patented May 6 1952 UNITED STATES PATENT OFFICE ATOMIZING NOZZLE FOR' SPRAYING VISCOUS LIQUIDS Bruce Buckland, Schenectady, andDonald C.

Berkey,-Scotia, N. Y., assignors to General Electric Company, a corporationcfNew York Application November 30, 1948, SerialNo. 62,634

4 Claims. 1

This invention relates' to liquid spraying nozzlesof the'type in which an'auxiliary fluid such as air or steam is used to facilitate the atomization process, particularly to such a nozzle as usedto spray fuel in the 'combustor' of a gas turbine power plant.

In power plants of the type described; it is, of course, desirable'to use'the least expensive fuel oil possible, whichis ordinarily thatknown commercially as bunker C oil, comprisingthecomparatively heavy residualfractions left from the refining proce'sseswhich produce gasolin'es, diesel fuels, etc. Theseheavieroils are so'viscous as to be difiicult of atomization by pressure" alone, as-is readily-accomplished in the case of kerosene and gasoline and-similar light oils by means of the so called pressure atomizirig or' vortextype-nozzles. The pressure atomizlng nozzles are customarily used in fuel injection systems for diesel'engin'es, while'the vortex nozzle ismost commonly used-in gas turbine combustors burningkerosene'orgasoline. While the 'use of comparativelyv expensive fuels, suchas kerosene, is acceptable in the case of highperformance gas turbine power'plants such as jet'engines for aircraft, in land-based power plantswhere fuel cost-is important it is necessary tojfind an efiective-way of'atomizing the heavy bunker C type fuel -oil. The-problem is'complicated bythe fact thatthe" term bunker 0 covers a multitude of substantially different commercial oils resulting from various refining processes, this term being a generic one applicable to the heavy residual oils commercially obtainable for burning in steam generating plants, locomotives, ships, etc. In a' gasturbine power plant for locomotive service, it is, of course, desirable that any of these readily available commercial oils may be used with good efficiency.

The nozzle known popularly as an air atomizing nozzle, in which an auxiliary fluid under pressure -(such as air, steam, or'other suitable gas) is used to facilitate breaking up the liquid into discrete particles, seems to offer-the best solution to the problem of providing an adequate fuel spray nozzle for usein gas turbine power plants burning heavy fuel oils. 'With conventional nozzles ofthis typeknown to the prior art, two principal difilculties arise: (1) it is almost impossible to obtain spray patternssufficiently symmetrical about the axis of thenozzlegand (2) the spray from the knownnozzles contains excessively large droplets; Thesedifilculties with the prior artznozzlesappearto arise-"from the practice of introducing the oil spray from a plurality of discrete orifices, and thefact'that with many of thepriorart nozzles the oil tends to fiow' along a-- surface of the nozzle until it is blown off by the blast of air in comparatively large particles.

Having found the-nozzles known to th'e prior art unsatisfactory for high performance service in a gas turbine locomotive power plant; the present invention has" for its-purposethe"provision of an improved air atomizing type nozzle'whi'ch will, over a Wide range of fiow rates' deliver the spray in'finely divided form, the spraypa'tte'rn being a conical sheet with an apex angle or cone angle which shows substantially no variation over an "extremely wide range ofoperation. To produce the maximum atomizing effect, as required for spraying viscous liquids, the airand oil are brought into close contactwhen' the air is at the maximum possible velocity. A still further object is to combine the features ofthe vortex and air atomizing nozzle to produce a nozzle giving a "conical spray with good at'o'mization and having completely uniform distribution'of the fuel aroundthe axis of the spray. Anotherobject isto provide a nozzle of the type described-giving good atomization and the desired spray angle at very low flow rates.

Otherobje'cts'and advantages will-be apparent from the following description taken inconnection with the'acco'mpanying "drawings, in which Fig. 1 shows schematically a fuel nozzle in accordance with the invention as appliedto the com bustor of a gas turbine 'powerplant, the power plant being more specifically described" in the copending application of Alan Howard, Chester S. Rice and Bruce- 0. Buckland, Serial No. 754,002, filed' June 11, 1947, and assigned to the-same assignee as the present application; Fig. '2 is a detail view'in section of the fuel nozzleits'elf';

Fig.3 is'a plan view partly in section of one-of the elements of'the nozzle takenat the plane 3 3 in Fig. 2; Fig. 4 is a plan view of another element to vigorouslydisrupt the sheet of 'liquid'and start the atomization process. In one form of the invention, the gas sheath is provided at onlyone side-of the liquid'sheet, while'in another form an atomizing gas sheath is brought intocontact with both sides of the liquid cone.

Referring now more particularly to Fig. 1, the fuel nozzleindicatedgenerally at l is shown supportedon a suitable'mounting pad in the outer wall Z Of a-gas-turbine combusto'r'having a suitable compresson-for instance, a multi-stagea'xial flow compressor, a part of which is shown at 3, arranged to supply air to the combustor through a transition passage 4. The combustion space is defined by an inner liner consisting of a plurality of telescoping sections having suitable air inlet openings for the admission of combustion air to the reaction space within liner 5 from the air supply space or plenum chamber 6 defined between the outer housing 2 and liner 5. The mechanical details of the combustor are more particularly described in the above-mentioned application of Howard-Rice-Buckland, and the theory of operation and arrangement of the air inlet holes of the combustor are disclosed in the copending application of Anthony J. Nerad, Serial No. 750,015, filed May 23, 1947, and assigned to the same assignee as the present application. It will be seen that the nozzle l is arranged to produce a spray pattern in the form of a hollow cone 1 coaxial with the liner 5. It will also be observed that the igniting device, which may be in the form of a spark plug 8, is so mounted that the spark gap defined by the electrodes lies substantially in the spray cone 1 so that a suitable fuel air mixture will be delivered to the spark gap during the starting cycle.

Fuel is supplied to the nozzle I, there being, of course, one nozzle for each of the multiple combustors in a gas turbine power plant, from either a main oil tank 9 or a starting oil tank In by means of a manually controlled selector valve I I. This arrangement is advantageous because of the difficulty of heating heavy fuel oils, such as bunker C, to make them fluid enough to be atomized properly during the starting process. In view of this difficulty, the power plant is started on diesel oil with the valve II in the starting position indicated in the drawing. After combustion is initiated, the valve can be thrown to the running position in which heavy fuel oil is supplied from the main tank 9. The supply of the fuels to the nozzle is effected by means of a suitable pump I2 which may be driven by a suitable power takeoff (not shown) from the main turbine shaft which drives the compressor 3.

The atomizing air for the nozzle is supplied in the following manner. In the outer wall of the transition passage 4 are a plurality of circumferentially spaced outlets 4a communicating with an annular manifold [3 to which comparatively hot air compressed by the compressor 3 is bled. Air from manifold I3 is led by a conduit I4 to a suitable cooler I5, through which may be circulated cooling air, cooling water, or even the fuel on its way tothe nozzle, in which case the heat of compression extracted in the cooler I5 is utilized to render the heavy fuel oil fluid enough to be properly sprayed by the nozzle. From cooler !5 the atomizing air goes by way of conduit [6 to an auxiliary atomizing air compressor, shown in the drawing as being a two-stage centrifugal compressor which may also be driven from the main turbine rotor. The compressor delivers the air at a pressure suitable for atomizing use in the nozzle I. As will also be seen in Fig. 1, conduit l8 delivers air from compressor 11 to an annular manifold 19 connected by suitable branch conduits 20 to the respective fuel nozzles. Since the atomizing air delivered to the nozzle is at a pressure in the neighborhood of 135 pounds per square inch absolute, the cooler I5 is required in order to limit the air temperature to a value which can be conveniently handled by the compressor and which will not be so high as to result in dissociation or cracking of the fuel oil in the nozzle.

4 Referring now to the mechanical details of the nozzle proper, it will be seen in Fig. 2 that the nozzle comprises an outer housing or casing 2|,

which may consist of a supporting post 2m, to which is welded a cylindrical nozzle casing 2lb having its axis coaxial with the axis of the combustor. The supporting post 2 la is provided with an axial drilled hole 22 for the oil supply and a larger parallel passage 23 for the air supply.

The nozzle casing 2lb is provided with a central recess comprising an end bore 24 and a main cylindrical recess 25, the latter being threaded at its forward open end to receive the end cap 26. Cap 26 has at its forward end a radially inwardly extending flange 26a and a plurality of circumferentially spaced axially projecting ears 2'! for protecting the pintle (described hereinafter) from mechanical damage.

Within the nozzle casing 2 lb is an inner nozzle body member 28 located in the recess 25 and hav ing at one end a radially extending flange 29 defining a circumferential groove in which is located a compressible packing ring 30 adapted to prevent leakage of fluid from passage 22 to 23, or vice versa. The mid-portion of inner nozzle body 28 is of roughly conical configuration and defines a circumferential groove 3| enclosed by a fine mesh screen 32 which serves as a strainer for the air entering through passage 23. As will be apparent from Fig. 2, this strainer screen 32 is supported on circumferential shoulders of the inner body 28 and may be secured in place by means of circumferential clamping wires shown at 33, 34 or any other suitable equivalent means. The forward portion of the inner nozzle body 28 forms a circumferential flange 35 having peripheral portions engaging the central bore in the end cap 26. End portion 35 is also provided with a plurality of axially extending grooves 36, the function of which will be seen hereinafter.

The central portion of inner body 28 defines an axial bore in which is received a pintle support sleeve 31 which is pressed, shrunk or otherwise suitably secured in the body 28. The left-hand end of the pintle support sleeve 31 is provided with a radially extending flange 38 adapted to support a cylindrical strainer screen 39, the other end of which is received on a cylindrical shoulder of the inner nozzle body 28. Strainer screen 39 may be retained in place by means of clamping wires 40. It will also be apparentthat the strainer 39 may be made as an integral cylinder and assembled between the pintle support sleeve 31 and the inner body 28 at the time the two are pressed together. It will now be apparent that oil from the inlet passage 22 flows through the screen 39 into the annular chamber 4! defined within the screen, whence it flows through a plurality of circumferentially spaced drilled holes 42 extending longitudinally through the inner body 28. It will also be seen in Fig. 2 that the forward end of the drilled holes 42 are connected by an annular groove 43 machined in the end face of inner body 28.

The purpose of the sleeve 31 is to adjustably support a central pintle 44 having a portion snugly fitting the bore of support sleeve 31 and an end portion threaded at 45 to receive a lock nut 46 which is in turn held by a suitable lock washer 41. It will also be noted that the end 45 of pintle 44 is threadedly received in the end portion 38a of sleeve 31. With this arrangement the pintle 44 may be adjusted axially a limited amount by turning the pintle so that it moves longitudinally in the bore 38a. The nut 46 and IdQkQ-"WBQSIIBI'. .412. then serveito :hold the. pintlecin its:desired:adjustedmosition. The purpose; of

this adjustmentuzwill. .be noted hereinafter. As. will; be. seen in? Figs-{2, the forward 1..end .of. the

pintle support sleeve: 31 projectsiinto a central.

bore48 of body- 28,:which bore forms-an air supply chambenconnected'by a, plurality of circumferentially spaced, :1 radially extending passages.

The extreme forward end of pintle 44 carries anend disk. 44a. 1

49:- With the.- annular chamber :31

Betweenctheinner body 28..and the end cap flange-:Zfiais a series of. three diskmembers 50,.

|, 52, the arrangement/and functionxof which will now beconsidered; The metering disk-.50 1

is seenin-cross-section in Fig. 2 -and in"planin Fig. 4. -At its-extreme outer periphery it ispro vided with a pluralityof circumferentially spaced square slots 53 -adapted to communicate with the axial grooves-36 by way of the'= annular groove a machined in theouter circumferential por tion-ofinner bodyend portion 35l It will be apparent f-rom -Figz that the grooves 53 communicate withthe annular chamber defined between the end cap 26 and the outer circumference of the disk'member' 5|. It should be particularly noted that the grooves 53have an aggregate cross section or effective area which" presents a substantial restriction to the how of air there- 7 through. In other-words, grooves'53 constitute metering orificesifo'r' limiting #the rate of flow of air, as-pointedout more particularly hereinafter. "Spaced inwardly from the grooves53 is a circumferential row of drilled holes 54 arranged to communicate with the annular groove 43 in i the end face-'ofbody28. At thecenter-of'disk' 53 is a =circular orifice 55 having a smoothly rounded entrance and cooperating with the adjacentportion of 'the pintle 44 to define a restricted annular; orifice which likewise meters the flow of airfrom" the chamber 48'.

The seconddisk member 5 I shown'in section in Fig. 2 andin plan view in Fig. 3. It comprises an annularrearward portion having an annular groove 56 adapted tocommunicate with the transverseholes 54metering plate 501 The forward portion" of 'plate: *5 l defines a" radially inwardly extending portion'forming a liquid'spray discharge orifice51f The-rearward annular portion of plate 5l-andr the "inwardly extending forward portionwith the conical forward surface 58ccoperatewith the adjacent surface of' meter plate to form'the .vortex whirl chamber from which the liquidfuer isidischarged through orifice? 5.1. The rearward-surface of disk member 5| is pro vided with-p a-plurality= of tangentially arranged grooves 59,-there'being fourof thesegrooves "in the'presentcase which communicate between the annular supply groove 56 and the-whirl chamber. It will be appreciatedby those skilled in the art that these grooves-59 are-metering-orifices or nozzles-for deliveringliquid into the whirlchamher at high tangentialvelocity soas to produce a strong vortex =whirl therein.

The forward portion of' disk member 5! is provided with radially and axially extending drilled holes 60-,* one'of-whichis.shown in the cutaway sectional portion of; Fig. 3. In the present case there are sixteen-'-of these- -holes equally spaced circumferentially. It: should" be observed that these holes 60- are not metering orifices ,orknozz erously' proportioned *p air with a minimum-pr V chamber defined betwe ,ai-thenozzle tip -plateiz andiitherpiiitleidislc- 44m i I but are merely geries; for delivering the dad to be f'festricted re drop to. the annular As::. will be;readilyapparent:from?=Fig.i=.2,1s;:the .1 nozzlectip: plate 52 is a simple circular. disk defim; ing;.a.:central. recess: 52a and: having..an. -outerv circumferential. portion 52b defining-a rabbet fit. for: locating. the'stip .platev 52: relative torthe.

diskzrmember 5|. Theouter circumference of.

tip.plate 52 istalsoprovidedi with a beveledzcoib. icalusurface adapted to'beuengaged by the flange 26a.of: the end cal-p.26."

for manufacturing convenience. .Those skilled in the art .will appreciate that they. can be. formed integral,,or.'fabricated separately and'brazedior welded together to form a nozzle tipmember."

Thessmethod ofiassembly and: relation of the. parts will-.nowbe obvious. The pintlezsuppcrtv sleeve 31 is pressed into-placeinthe inner body 28 with the screen 39 in assembled relationafter adjacent the inner body' 28 and the pintle" 44 threaded into the support sleeve 31. adjustment of the pintle 44 in the sleeve. 31 provides a ready means for adjusting the efiective the pintle end disk 44a and the adjacentportion oftip member 52. With the lock nut 46 and lock washer 41 secured so as to hold the pintle in desired axial position, the entire assembly may bepositiond in the nozzle housing 2") and the end cap 26 assembled so as toclamp'members 52, 5|, 50', 28 and'sealing ring 30 into tight.

engagement with one another. The assembly now provides-an oil passage from the inlet 22 by way of chamber 24, filter screen 39, annular chamber- 4|, drilled holes 42, annular groove 43, drilled holes" 54',annular'groove 56, orifice slots 59'. into the whirl chamber 5la.

The vortex whirl created in chamber 5 la by the the pintle 44 and the whirling body of oil. Atomizing air is supplied to this air core in the whirl chamber by way of the metering orific 55 and the communicating passages 48, 49,- chamber 3|, filter screen 32 and annular air supply space 25. Atomizing air from space 25 also passes through filter screen 32, chamber 3|, the axial grooves 35, annular groove 36a, axial grooves 53 in metering {plate 50, thence through the radia air supply holes 60.

Inv operation the whirling body of 'oil in the vortexchaniberspills continuously in a smooth uniform conical sheetover the edge of the discharge orifice 51. This liquid tends to leave angle, the value of which depends on the diameter of theorifice, the velocities in the 'whirl Y chamber, the viscosity of the liquid, and numerous other factors with which those skilled in the I art are thoroughlyacquainted. It need-only be angle of the whirl chamber.

stantially at, the,, :middle of annular orifice 6|.

It-may-be noted that, the coneangle" of the atomized spray la emerging from orifice 6 I need ---not= be-"the same asthe intrinsic angle *ofthe- Thetdiskmember jl and nozzle tip -plate15 areillustrated asbeingformed separatelys merely which; the disk members 50, 5|, 52 may be placed The axial.

.width of the annular orifice 6| defined between nozzles 59 leaves an annular air passage between the discharge orifice 51 in the form of a hollow conical sheet having a substantially fixed vertexvortex whirl chamber |a. By properly proportioning the annular orifice 6| so that it is longer (in the direction of flow) than it is wide, the angle of spray cone 1a emerging from orifice 6| maybe made to conform to the direction of the orifice Thus, a single set of nozzle parts forming the vortex whirl chamber can be utilized to provide a range of various ultimate discharge angles, simply by substituting a tip plate 52 and pintle 44a forming an orifice 6| of the proper shape and direction. In other words, the basic nozzle parts are designed so the whirl chamber 5|a produces a spray cone -'|b which intersects the entrance to orifice.5 while the shape and direction of orifice 6| determine the final cone angle of spray pattern la, the two air streams62, 63 serving to prevent the spray from contacting the surfaces of orifice 6L1 It may also be noted that the final spray cone angle may be altered somewhat by changing the size of the annulus 5| relative to the-size. of the free" spray cone 11) produced by the whirl chamber 5|a. If annular orifice 6| is smaller than the free spray pattern at the location of the orifice 6|, then the finalcone angle of spray pattern 1a will bedecreased. Conversely, making orifice 6| larger than the free spray results in an increase in the final spray angle. There is a substantial annular air passage on either side of the sheet of liquid lb. 'Ihus,-with the conical sheet of liquid lb passing through the orifice 6|, as shown in Fig.

2, there are provided two separate paths for atomizing air, one indicated by the fiow arrows 62 on the outside of the cone of liquid, the other being indicated by arrow '63 on the inside of the liquid cone. It will be observed that while there is a substantial pressure drop across the metering orifices formed by the grooves 53 and the central metering orifice 55 in meter plate 50, there is also a substantial further drop in pressure of the atomizing air across the annular orifice 6|. This pressure drop, of course, produces a very substantial increase in velocity of the air flowing through orifice 6| on either side of the liquid cone. Thus, the cone of liquid in which the particles move at substantially uniform velocity after leaving the discharge orifice 51 is surrounded both inside and out by a stream of air which is being rapidly-accelerated as it passes through the orifice 6|. This 'increase in relative velocity of the air and'oil produces a'very strong shearing effecton the oil particles, and this shearing effect has a. powerful tendency to break up the solid cone of, liquid into discrete atomized particles. Thus, it will be seen that the air and oil are brought together at a point where the velocity of the atomizing air'is highest. For this reason, and in viewjof the acceleration of the air through the orifice 6|, there is a maximum tearing effect? produced by the air on the sheet of liquid.

The spraypattern lb is preventedfrom collecting on the surfaces ofiorifice 6| and-is maintained substantially centered in the orifice in the following, manner. .As indicated above, the inherent design characteristics-ofthe liquid discharging parts of thenozzle determine the in- 8 plate 52 is decreased and the flow ofair as indicated by the arrow 62 is decreased. The result of this is that the static pressure of the atomizing air tends to build up in the passages 60 and the annular space defined between the conical sheet of liquid 1 and the adjacent portions of tip plate outside of the conical sheet of liquid have a very definite stabilizing action tendin to maintain the conical sheet of liquid substantially in the center of the annular orifice 6|. It has been found that this arrangement produces a uniformly finely divided spray, with a substantially constant spray angle.

It will beappreciated that there are a number of design factors which must be carefully watched in the construction of a nozzle in accordance with the invention. In the first place, the air supply passages are generously proportioned so that the pressure of air supplied to the metering grooves 53 and the central metering orifice 55 in meter plate 50 is approximately the same. Likewise the I air passages in the disk member 5| are generously proportioned so that the pressure of the air sup- 7 plied to the upstream side of annular orifice 6| on either side of the liquid sheet is equivalent to that existing at the downstream sides of the orifices 53, 55. Then the rate of air flow to the opposite sides of the liquid sheet may be ac- I curately controlled by careful design of the effective size of the orifices 53, 55. These sizes may be so selected that an equal rate of flow of air to the inside and outside of the conical sheet of liquid is provided. The result of this arrangement is that the static pressure inside and outside the liquid cone 1 at the upstream side of orifice 6| is equalized, as is also the rate of flow ofv air indicated .by arrows 62, 63 through the orifice 6|. If, for some reason, the rate of air flow to the inside and outside of the liquid cone should become unbalanced, the result will merely be that the cone will not be. maintained exactly in the center of the annular orifice 6|, but will be maintained stable in some equilibrium position with the air paths 62, 63 of unequal size corre-- sponding to the unequal rates of flow. The

stabilizing effect of the two streams of air on the cone angle will be the sameas described above-- It is desirable that the rates of fiow in the two streams of air be equal so that the liquid cone will be centered approximately in the orifice 6|.

v improved nozzle, it may be noted that the com-'.

trinsic angle of the spray, which will tend to .-With respect to the pressures existing in this bustion chamber pressure will, during operation, vary from zeroto a value in the neighborhood of 70 .pounds per square inch gage. Since the atomizing air compressor I1 is driven from themain turbine rotor the atomizing air pressure will likewise varywith speed of the power plant, the maximum air supply pressure being in the neighborhood of pounds per square inch. The orifices in the metering plate 50 are so designed that the atomizing air pressure ratio across the whole nozzle can vary in a wide range up to 2 or more. During starting, the atomizing air pres- .39 sure ratio is usually about 1.05, while the air pressure ratioduring running-is: about 1.6. The pressure dropthrough' meteringorifices 53, 55 is in the neighborhoodof 7 per cent of the total pressure drop, across thenozzle.

Theoilnozzlesformedbythe slots 59 in disk member 5| are designed. to give liquid velocities inthe whirl chamber sufiiciently high toproduce good symmetrical distribution of liquid in the spray cone at the'lowest desired operating speed. Also, the diameter of the air metering orifice 55 is somewhat less than that of the oil discharge orifice 51, the differencebeing sufficiently great that there will be no tendency for oil inthe whirl chamber to spill over the edge of the orifice 55 into the air supply chamber 48.

Representative. values of the more critical dimensions not .a .sample nozzle are as follows:

Table of dimensions of arepresentativenozzle {For delivering-maximum"flow-of 90 galz/hr. at oil supply pressure-cram 1bL/in;'.-and airpressure' of1$120 =lb./in.

Inches Orifice 55, diameter .30 Pintle 44 at orifice 55, diameter .156 Vortex chamber 5m, max. diameter .875 Orifice 51, diameter .375 Pintle end disk 44a, diameter .75 Width of annular orifice 6| .036 Oilnozzle slots 59, square cross section with each side .031

In starting the power plant of Fig. 1, the main turbine rotor is turned over by means of a suitable starting motor with the fuel selector valve inthe-starting position so that diesel oil issupplied from tank ID to the nozzles. At low speeds, the auxiliary atomizing air:compressor supplies comparatively low-pressure air, butthe inherent nozzle design will insure sufilciently good and even distribution of. particles in theliquid spray cone to fire .the .power .plant at'oil supply pressures as low as perhaps 3pounds per square inch. At a-speed of about 10 per cent of full rated speed, the ignitingdevice B is energized and combustion begins. As.v the speed in:--

creases, the pressure of. the atomizing-air increases, and, .of course, the discharge pressure of the fuel pump increases correspondingly. At idling speed, which may be approximately-"Z per cent of the full ratedspeed, the fuel selector valve may be switched so that heavy fueloil is supplied from the main tank 9.

With this improved fuel, nozzle,- the use of the. vortex ..type of liquid 'spray;;nozzle. insures an...e'ven:. circumferential distribution of the- .liquid... The ..use of .an.auxiliary-atomizing-gas insures good atomizationof heavy liquidfuels, and the novel arrangement .of'the'atornizing air on both theinside and outside of the spray cone pattern serves to give still better atomiza-- tion and .at the same time provides the novel stabilizing effect on the cone. angle. Thus the invention: achieves a particularly effective" arrangement for spraying ,gheavyi fuel :4 oils with satisfactory operation over :1 an=..extremely wide operating range, .as requiredin :gas turbine power plants.

While: a preferred form of: the invention. has been described above inconnectionwith Figs. 1-4,- it should be understood that many .modifications ..are .possible, including; the" following: Fig. 5 illustrates :an arrangement in which :-the atomizing air is supplied'only'tothe outer surface of the fuel spray cone. In the construction shown,-the-nozzle body defines a:central bore 10 I'Lforming the .oiLsupply passage, a plurality of .circumferentialy; spaced air supply passages 72 and athread at-13 on. the outer surface for receivingthe'end cap 14; Secured between end cap 14 .and bodyv lfiarewa nozzle tlpmember .15 and an. intermediate member '16.

Member. 15 defines a central liquid discharge orifice 'l"l,--a cylindrical recess 18 forming the vortex whirl .chamber, the .oil nozzle slots'19 and .an annular oil-supply'passage 80. As will be apparent from the drawing, member 15 has an axially extending portion 15d surrounding the outer. circumference of member'1'6 so that the two are heldinproper coaxial relation.

The forward surface of .thernozzle tip .member 75 is provided with axially :extending ribs 152) which cooperate with the adjacent conical. surface of .cap- 1'4 to provide axially and :radially inwardly extending air :supply passages.

Theintermediate member It-defines a plurality of circumferentially-spaced drilled holes 8| through which oil passesf-rom the supplyrbore H .to the nozzle slot supply groove 80. Mem- .space surrounding the nozzle spray orifice 11,

the air leaving in the manner-indicated by the arrow .10 through the small annular-space defined between thespray cone 1 and the adjacent perimeter of the central orifice in nozzle cap 14. Here again it will be apparent that any' tendency of the spray cone 1 toopen up so as to increase the cone .angle. and bring the spray pattern nearer to the annular edge of-the nozzle cap 14 will result inan increase in static pressure fo the atomizingair, tending todeflect the cone back to its original condition so as to maintain substantially constant the size of the annular air gap surrounding the spray pattern. Here, of course, there is no corresponding tendency to prevent decrease of the spray cone angle; as .was .described in connection with Fig. 2 With .some ..nozzles, and-.forsome applications,. thisztype of .nozzlemay be adequate since it obtains the same symmetrical distribution of the-liquid spray with good atomization and a substantially stable spray .cone angle.

The converse arrangement, in which atomizing air is supplied only'to the inside of the spray cone is illustrated in Fig. 6;1-1618 the nozzle -body has at one end a central opening defined by a radially inwardly-extending flange 85a. The otherv endof the central bore through the IlOZZlGbOdYiiSF-CIOSGd bya threaded plug 85. The nozzle body'85'also defines a first bore portion 81 forming an annular air inlet passage and a second bore portion 88 forming'the oil inlet.

Within'theboieportion 81 is a casing member.89 defining acentral air-supply chamber 90 with a pluralitypf bircumferentially spaced holes 9|. ,The left-hand end of the central recess 90 is threaded to receive an end cap 92 which may have a hexagonal socketat 93 for inserting a hexagonal wrench for assembly purposes. A suitable air strainer screen 94 may be formed as an integral cylinder supported on shoulders formed on the member 99 and the end cap 92, respectively. It will be apparent that this screen may be assembled on member 89 and the end cap member 92 then threaded into place. The right-hand end of the inner casing member 89 forms a rather thin annular extension 95 having a conical sealing surface for engaging a similar cooperating surface on the adjacent end of the second inner casing member 96. Member 96 has a central bore receiving the pintle 91 and is threaded at 98 so that the pintle may be adjusted longitudinally as described above in connection with Fig. 2. The lock nut 99 and lock washer I are similarly arranged and perform the same functions as the corresponding elements 46, 41 in Fig. 2. The second inner casing member 96 also defines a plurality of circumferentially spaced axially extending drilled holes IIJI communicating with a passage I 02 formed in the end wall of easing member 96. The outer circumference of casing 96 is recessed to form an annular oil supply passage I03 enclosed by a strainer screen I04 in a manner which will be apparent from the drawing. From the supply space I93, oil is carried by a plurality of drilled holes I65 to an annular oil nozzle slot supply chamber I96 defined between the end of casing 96, the end cap 85, and the outer circumference of the nozzle tip member I01. Oil is supplied through the four tangential nozzle slots I08 to the whirl chamber defined in the tip member I0! and the adjacent end face of the inner casing member 96. Here the pintle 91 is provided with an end disk 91a which defines an annular orifice IEI'Ia with the adjacent circumference of the nozzle tip mem" ber I01 in the same manner described in connection with Fig. 2. The difference is that oil from the whirl chamber spills over the edge of the nozzle tip member through the annular orifice IO'Ia. atomizing air being supplied through the passages 9|, 90, I 0|, I02, to the air core within the vortex chamber, thence between the inner surface of the spray cone and the adjacent surface of the pintle and disk 91a, as indicated by arrow lfl lb.

This arrangement also provides good atomization of heavy fuel oils with the desired even distribution of oil symmetrically aboutthe axis of the nozzle, while maintaining a substantially stable cone angle. The modifications of Figs. and 6 may have some advantages over the structure of Fig. 2 from the standpoint of mechanical complexity.

It will be apparent to those skilled in the art fice of substantially larger diameter than and coaxial with the first and spaced axially forward therefrom, the second orifice surrounding the normal spray pattern from the first orifice and defining a restricted annular passage therewith, a central pintle supported on the nozzle body and having an end disk member disposed within the spray pattern, the circumference of said disk forming a restricted annular passage with the inner surface of the normal spray cone pattern, said second discharge orifice and pintle end disk defining an annular gas and liquid discharge orifice spaced axially forward and radially outward from said first orifice, and walls defining passages for supplying an atomizing gas under pressure to both the inside and the outside of the spray cone pattern so that a conical sheet of atomizing gas flows through said annular orifice on both sides of the spray cone.

,2. In a liquid spray nozzle of the type employing an auxiliary gas to facilitate atomization, the combination of a nozzle body having walls defining a vortex whirl chamber with a first central circular discharge orifice, walls defining passages that analmost infinite number of mechanicalmodifications may be made in the three types of nozzles illustrated herein, and we desire to cover by the appended claims all such changes and modifications as fall within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

'1. In a liquid spray nozzle of the type employing an auxiliary gas to facilitate atomization, the combination of a nozzle body having walls defining a Vortex whirl chamber with a first central circular discharge orifice, walls defining passages for supplying liquid at high tangential velocities to'the outer circumferential portion of the whirl chamber whereby liquid is discharged from said orifice with a spray pattern in the. form of a hollow cone, walls defining a second discharge ori"' for supplying liquid at high tangential velocities to the outer circumferential portion of the whirl chamber whereby liquid is discharged from said orifice with a spray pattern in the form of a hollow cone, walls defining a second discharge orifice of substantially larger diameter than and coaxial with the first and spaced axially forward therefrom, the second orifice surrounding the normal spray pattern from the first orifice and defining therewith a restricted annular passage, a central pintle supported on the nozzle body and having an end disk member disposed inside the spray pattern, the circumference of said disk forming a restricted annular passage with the inner surface of the normal spray cone, said second discharge orifice and pintle end disk defining an annular gas and liquid discharge orifice spaced axially forward and radially outward from said first orifice, Walls defining passages for supplying an atomizing gas under pressure to both the inside and the outside of the spray cone pattern so that a conical sheet of atomizing gas flows through said annular orifice on both sides of the spray cone, and means defining a metering orifice associated with at least one of said air supply passages for equalizing the rate of fiow of atomizing air to the inside and outside of the spray cone pattern.

3. In a wide-range atomizing nozzle for spraying viscous liquids, the combination of a nozzle support member having a liquid inlet passage and an atomizing gas inlet passage, a body secured to the support member and having a central longitudinal bore of circular cross section including a first end portion communicating with the liquid inlet passage and an intermediate portion communicating with the gas inlet passage, a nozzle end cap of circular cross section threadedly engaging the nozzle body to define a forward continuation of the central recess in the nozzle body, a first inner nozzle body member of circular cross section located in said intermediate recess and having a central bore supporting a sleeve member with an end portion projecting into said first bore portion, said projecting sleeve end portion having a radially extending flange, a cylindrical filter screen member supported at one end on said end flange and at the other end on a circumferential shoulder formed on the adjacent end portion of said inner nozzle body, a central pintle member having a stem portion supported in said sleeve with a threaded end portion projecting from the sleeve and having at the other end a pintle end disk member axially spaced from said sleeve, the threaded end of the pintle stem being threadedly received in said sleeve whereby the pintle may be adjusted axially, lock nut means engaging the projecting end of said threaded pintle stem for securing the pintle in a desired axially adjusted position, a circular metering plate member supported in said end cap and abutting the end face of the inner nozzle body member, said metering plate defining a first central circular orifice of larger diameter than the pintle stem so as to define therewith a restricted annular metering orifice, the metering plate having also a circumferential row of axial passages of restricted cross-section area forming second metering orifices, and a circular nozzle tip member located within the end cap, the end cap having a radially inwardly extending flange clamping said nozzle tip member in abutting relation with the forward face of said metering disk member, said nozzle tip member forming a cylindrical vortex whirl chamber coaxial with the pintle stem and a third circular liquid discharge orifice forming an annular passage with the pintle stem, said nozzle tip member also defining a fourth coaxial discharge orifice of a substantially larger diameter than said third orifice and spaced axially away therefrom, the circumference of the pintle end disk being adjacent and cooperating with said fourth orifice to form a restricted annular discharge passage of a width which is adjustable by axial adjustment of the pintle member, the inner nozzle body member, metering plate and nozzle tip member cooperating to define passages for supplying liquid from the annular chamber defined between said first filter screen and the pintle support sleeve to the outer circumferential portion of said vortex whirl chamber with a high tangential velocity component whereby a strong vortex whirl of liquid is created, the inner nozzle body member, metering plate and nozzle tip member defining passages for supplying atomizing gas from said inlet passage to the annular spaces formed at either side of the normal spray pattern by the pintle end disc and fourth orifice respectively, the restricted gas passages in said metering plate being of such a size as to supply gas substantially uniformly to both sides of the spray cone, whereby the atomizing gas flows through the annular discharge orifice on both sides of the normal spray cone pattern so that the gas and liquid are brought into close contact where the gas acceleration and velocity are a maximum.

4. In a wide range atomizing nozzle for spraying viscous liquids, the combination of a nozzle body member with a liquid inlet port adjacent the rearward end thereof and a gas inlet port in an intermediate portion thereof, said body defining a central longitudinal bore of circular cross section including a first rearward end portion communicating with said liquid inlet port and,

an intermediate portion communicating with said gas inlet port, a nozzle end cap of circular cross section secured to the forward part of the nozzle body to define a forward continuation of the central recess in the nozzle body, a first inner nozzle body member of circular cross section located in said intermediate recess and having a central bore, a central pintle member having a stem portion adjustably secured in the bore of said inner nozzle body member and having at the forward end thereof a pintle end disk member,

a circular metering plate member supported in said end cap and abutting the forward end face of the inner nozzle body member, said metering plate defining a first central circular orifice of larger diameter than the pintle stem so as to define therewith a restricted annular metering orifice, the metering plate having also a circumferential row of axial passages of restricted crosssection area forming second metering orifices,

- and a circular nozzle tip member located within the end cap, the end cap having a radially inwardly extending flange clamping said nozzle tip member in abutting relation with the forward face of said metering disk member, said nozzle tip member forming a cylindrical vortex whirl chamber coaxial with the pintle stem and a third orifice forming an annular liquid discharge opening with the pintle stem, the outer diameter of said vortex whirl chamber being substantially greater than the diameter of said third orifice and said third being at least slightly greater in diameter than said first orifice, said nozzle tip member also defining a fourth coaxial discharge orifice of a substantially greater diameter than said third orifice and spaced axially forward therefrom, the circumference of the pintle end disk being adjacent and cooperating with said fourth orifice to form a restricted annular discharge passage of a width which is adjustable by axial adjustment of the pintle member, the inner nozzle body member, metering plate, and nozzle tip member cooperating to define passages for supplying liquid from the liquid inlet port in the body to the outer circumferential portion of said vortex whirl chamber with a high tangential velocity component whereby a strong vortex whirl of liquid is created having an air core of a diameter greater than said first orifice and less than that of said third orifice, the inner nozzle body member, metering plate, and nozzle tip member defining passages for supplying atomizing gas from the gas inlet port to the annular spaces formed at either side of the normal spray pattern formed by said third orifice, the orifices in said metering plate being of such size as to supply gas substantially uniformly to both sides of the liquid spray cone, whereby atomizing gas flows through the annular discharge orifice on both sides of the normal liquid spray cone pattern so that gas and liquid are brought into close contact at the point where gas acceleration and velocity are a maximum.

BRUCE O. BUCKLAND. DONALD C. BERKEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 484,074. Wilgus Oct. 11, 1892 1,977,798 Korth Oct. 23, 1934 2,303,104 Abbey Nov. 24, 1942 2,354,842 Spence Aug. 1, 1944 FOREIGN PATENTS Number Country Date 10,710 France July 29, 1909 (Addition to 396,47 6) 63,152 Denmark Feb. 5, 1945 528,018 Great Britain Oct. 21, 1940

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