US2928612A - Liquid atomizers - Google Patents

Description

2 Sheets-Sheet 1 IN VEN TOR. CALVIN D. MACCRACKEN ATTORNEY C. D. MECCRACKEN ETAI- LIQUID ATOMIZEIRSA By JAMES M. RELPH sss sss mm mv Om March l5, 1960 Filed Jan. 14, 1957 March l5, 1960 c. D. MaccRAcKEN EI'AL 2,928,512

' LIQUID AToMlzERs Filed Jan. 14, 1957 2 Sheets-Sheet 2 PRESSURE 30o PslG.

LIQUID- NO.6 BUNKER C OIL LIQUID TEMP.- l60'|80F.

HOUR

aQo

FUEL FLOW- LBS; PER

DEGREES- HANDLE ROTATION JQQ4 $1916- INVEN CALVIN D. MACCR EN BY JAMES M. RELPH ?1g'-5- 8MS-Mw ATTORNEY lthe internal passages.

United 2,928,512 LIQUID Aroivnznns Calvin D. MacCrackeu and James M. Relph,.Tenally, NJ., assgnorsto Jet-Heet, Inc., Englewood, NJ., a corporation of New York Appicatien January 14, 1957, Serial Nc, 633,929 claims. (ci. 239-446) There, are numerous instances such as in marine and industrial burner applications where it is highly desirable LO have a mechanical fuel atomizer operable at constant -fnel supply pressure and with output variable readily over a fuel llow volume range from a maximum to a minimum ow ratio of as much as., o r more than, 40 to l without appreciable change in the atomizer spray angle or conditions of atomization. Previously it was necessary to either change the pressure ofthe fuel supply or in cases where the atomizer has a return flow line to vary the pressure in the return line, or to disconnect the orifice plate from the remaining portions of the atomizer and replace it with one of dierent size in order to change the output of the atomizer.

In accordance with this invention wide variations of fuel output volume with excellent conditions of atomization may be achieved without varying the fuel supply or return pressures or the sizes of any of the atomizer parts. A preferred embodiment of the invention includes an atomizer having a plurality of circumferentially spaced symmetrically arranged discharge orifices which are supplied with liquid to be atomzed from a plurality of in- `ternal passages located in the atomizer body and having inlet ports at spaced locations along the atomizer body bore which are sequentiallyopened to the liquid supply by an axially slideable internal valve. The valve ymay be moved to any position to uncover one or all of the passages and to vary the atomizer liquid outlet capacity in accordance with the number of passages feeding'liquid to Vthe orifices. Liquid is delivered to each of these orifices in a high velocity vortex flow which is established in c onical swirl chambers communicating with the orifices and Thus by selectively openingr and closing the individual passages lby means of the axially slideable valve, it is possible to obtain a maximum ow rate volume to a minimum flow rate volume ratio of as much as 40 to l.

An atomizer constructed in accordance with this invention may be readily adaptable for any ordinary clean liquid atomization such as water, or fuel atomization as in burner applications. it has lbeen found thatA for burner use the fuel will atomize with substantially the same spray cone angle and -flame conditions when one, two or more o f the orices is supplied with and is atomizing fuel. When the second orifice is cut in after the fuel from the frrst'vhas been tired, the arrangement ci discharge iS kauch that the spray angles and flame Pattern will bleed into .one 1big spray cone rather than -for'm two individual cones. The @remit-er has little Vappreciable .change ,in aterriza reference to Patentv t *Ce 2 spray angle or flame burning conditions over its wide range of fuel atomizing output.

Accordingly it is an object of this invention to provide an atomizer which is'supplied with liquid at constant pressure and is .capable of atomizing Vthe fuel over a wide range of atomzed liquid output.

A further object is to provide an atomizer which is supplied with liquid at a constant pressure and has a plurality of discharge orilices in communication with 'separate liquid delivery passages, and includes a valving element which is movable gradually to effect communication of each passage in succession with the liquid to be atomzed'.

A further object is to provide a liquid atomizer of lthe character described which is simple in design, rugged in construction and economical to manufacture.

For a better understanding of the invention, its operating advantages, and specilic objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

In the drawings:

Figure l is a side elevation, partly in section of an atomizer gun embodying the invention;

Figure Zis an enlarged sectional view of the atomizer portiony of thegun assembly of Figure l;

Figure 3 is a sectional view of the distributorportion 0f the atomizer taken on the line 3 3 of Figure 2;

Figure 4is an enlarged end elevation of the rearface ofthe sprayer plate portion of the atomizer;

Y Figure 5 'is a sectional View of the sprayer plate taken on the line 5 5 of Figure 4; n Figure 6 is' a curve showing-the variation of atomzed liquidmoutput obtainable with an atomizer embodying the inventionr" v f Figure 7 is al schematicV development of the arrangement of the internal passage inlets of the distributor barrel of another embodiment of the invention and showing the manner in which the axially movable valve uncovers each inlet in succession as Vit is moved towards the forward or discharge end of the atomizer; and

VFigure 8 is a sectional view taken on the line 8,-8 of Figure 7. Y

Referringto the drawings'in particular, the invention as embodied therein includes an atomizer gun generally Vindicated 10. In the usual case this gun assembly will be incorporated in a burner to discharge atomzed fuel into the combustion chamber of a furnace, although the burner assembly and furnace have been omitted from the drawing as unnecessary to an understanding of the invention. a' The atomizer gun -10 includes an elbowmember 1,2 having an inlet conduit 14 through which a liquid fuel is supplied under constant pressure'from any suitable source (notvshown). The forward or discharge end of the elbow member 12 is internally threaded to receive a tubular barrel or sleeve 16 which, inturn, is externally threaded at its forward end as at 17 (see Figure 2) to receive an atomizer assembly 18.V Liquid is supplied under pressure through the inlet 14 and through the interiors of the elbowmember 12 and the barrel 16 tothe atomizer assembly 18 under the control of a valve element generally designated 20.

The valve element 20 is affixed to the forward end of a long 4s halt 22 which extends from the atomizer assembly 18 backwardly through a bearing sleeve 24 threaded onto the rearend'of the elbow member 12,. A suitableV packing 25 prevents theY escape of liquid from the inside of the elbw member 12. `The shaft 22 extends rearwardly beyond the Vedge of the elbow member 12 and is enclosed by .a tubular housing ,26 which is fastened'tc the elke-W ymember ,1 2 as by screws 27,v "The housing 26 is closed which is positioned adjacent an indicator dial 40 having a calibrated scale arranged tol give a relative indication of the fuel output of the atomizer from settings of to 360. i

` The spindle piece 30 extends inwardly beyond the plug .2S and has a hollowed internal portion in which is located a plurality of radially projecting spline keys 42 which normally, ride in the grooves of a spline 44 afiixed to the end of the shaft 22. The spline keys 42 permit inde lpendent axial movement of the shaft 22 relative to the Lspindle piece 30but rotation of the handle 32 will cause rotation of the spindle Vpiece 30 and hence rotation of .the shaft 22 through the medium of the spline keys 42 and the spline 44. 1 Y

A worm gear 46 is aiiixed to the shaft 22 and-normally engages a plurality of bolt-like teeth 48.v which are aixed to and protrude inwardly from the wall of the housing 26. Rotation of the shaft 22 by means of the handle 32 V.effects theaxial movement of the shaft as theworm gear alixed thereto'is advanced by engagement with the .boltliketeeth48. v

' Referring to Figure 2, the atomizer assembly 18Vincludes a housing piece or distributor 50 which is threaded onto the barrel 16. The distributor 50 is hollow, having a cylindrical bore defining an internal liquid delivery chamber 52 which is closed at the forward end but which is open at the-opposite endrto accommodate the valve element 20, the latter being capable of reciprocating 'axially therein. The wallsof the distributor are beveled l,as at 54 to permit unhindered flow of liquid from the .barrel 16 into the distributor when not blocked by the valve element 20. The valve element 20 has a tight sliding fit in the distributor liquid supply chamber 52 with a substantially liquid tight sliding seal being provided by a packing ring 56 affixed to theV shaft 22'and held thereon against the valving element 2,0 as by a nut 57. A sprayer plate 58 is positioned on the discharge end of the distributor 50 and is held in place thereon by a cap nut 60 threaded onto the distributor 50 as at 17a and aligned thereon by suitable pin and slot connections as at 62. 1 In accordancewith the invention the sprayer plate 58 is provided with a plurality ofdischarge orifices 64 which in this instance are symmetrically arranged at circum ferentially spaced locations. In the present instance'there are six orifices arranged with their dischargeaxes parallel, and closelyspaced toetfect atomization into a single spray cone.V AV number more or lcssthan six could be provided without departing fromv the'principles Y been found desirable to makethe diameters andA the I depths of the orifices which are used at low fuel rates 'smaller-'than the corresponding dimensions of. those orifices which come into play at higher ow rates.

Each of the orifices 64 communicate with cylindrical swirl chambers 66 through intermediate frustro-conical chambers 68 which are drilled in the sprayer plate` 58 -(see Figures 4 and 5)l.- E ah swirl chamber 66 is supplied with'liquid from three substantially rectangular Vtangentially directed` slots 70a, -70bj and` 70e of varying sizes. The largerV twoV of the slots 70a and 79)b. `c'orr 1l `muncate with a longitudinal passage 72a anda branch passage 72b perpendicular thereto drilled in the distributor y50. The smallest slot 7 0c communicates with a longitudinal passage 72e also .drilled in the distributor 50. The liquid supply chamber 52 of the distributor 50 is provided with a plurality of ports 74 (which in this instance are of equal diameters) arranged in equally spaced positions along the length of the bore at circumferentially offset locations. The ports 74 are connected by means of shortl lateral passages 76 to the longitudinal passages 72a aricl`72c.v Y

The larger two tangential slots al and 7011 are both supplied with fuel through passages 72a and 72b fed by a single port 74, and the smallest slot 70e alone is supplied with fuel through the passage 72e fed by a single port. Thus when a port 74 is cut in which feeds the passage 72c and the smallest slot 70e, a fuel output of under 50% of the orifice maximum output may be obtained. However, if a port feeding the larger slots 70a and 70b is cut inbefore the smallest slot-port, the output of the orifice will be as much as 98% capacity. Therefore for more gradual fuel output increase the smallest slotY 70e of each orifice is arranged to be cut in before the other two. In this connection it will be appreciated that many variations in fuel output for each orince 64 may be achieved by changes in the sizes of the tangential slots 70a, b, c and the manner in which they are arranged .to cut in. Y

The following table contains representative dimensions in inches for the various sprayer plate orifices and their associated-slots, for a typical installation in which the ow rate was made variable between 0 and 4300 pounds per hour of No. 6 fuel oil: f

In the foregoing case, the slot widths were all .0625",

and all of the swirlchambers had a maximum diameter of .281" in a sprayer plate .275" thick; the centers of the discharge orifices being .365" from the center of the sprayer plate.V

The operation ofthe atomizer is as follows: With the Yvalve 20 in a closing position (see Figure 2), the ,fuel will be confined under pressure in the elbow member 12 and the barrel 16, and will not flow through the liquid` supply chamberSZ of the distributor 50 into a port 74.

,As the handle 32 is rotated, the valve element 20` is moved forward in the chamber 52 `and the rear Yedge thereofV passes .beyond one of the ports 74 to open it and permit fuelV to flow into the port. The first port in line is arranged to communicate with the smallest one ofthe orifices 64 through itsassociated small tangential slot 70e and the passage 72e. Theorifice size chosen for -frst operation is the size .whichwill obtain a fueloutput of lowerr'than 100 pounds per hour so. thatvery small quantities of fuel may be discharged .from `the atomizer as it is cut in. Further movement of the valve element `20 is effective to uncover the port feeding the passages` 72a and 72b and the Aslots 70a and 70b ofthe same orifice 64. Additional movement of thevalve element 20 is effective to uncover first the port feeding the `small tangential slot 70c and then the port feeding the slots 70a and 7011 of each of the other orifices in succession until all of the orifices are discharging fuel. -1 A curve showing the fuel output obtainable for vario rotational positions of the handle32 is shown in Figure 6. It can be seen that variations in fuel output'from 'below 200 to over4300 poundsper hour can be obtained with settings from zero tog360 of the ,handle 32.` `The variations in the flow rates which are obtained with the aterri-` areas-,eta

izer of the presentl invention may occur ,at hundle'setting increments which may be made small enough to provide for a gradual ever .increasing fuel output. I-.t1Will .be noted in this connection that when the valve element 2 0 is moved to uncover .the ports 74-there is a brief period where a largeincrease of fuel rate occurs vshortly after the port has been Vopened and then there is .a longer period where relatively little or no increase in fuel rate occurs until the next port has been uncovered. 'I his is shown graphically by the dotted lines on the curve of Figure 6. (In this case the ports are fully open at each 30 increment of handle rotation.) By choosing two relatively small sized orifices 64 out of the group of six it `is possible to use a combination of atomizers or a single atomizer in such a way that the 4small orifices will come into play at the times when small increases of fuel rate is desired or for initial cut-in at low burning load requirements.

The embodiment shown in Figure 7 is advantageously used in those instances in which it is desirable or necessary to have very small and even Aincrements of change of fuel output over the operating ranges incurred. For some controls it is preferable to have a smooth curve of ow versus handle position. In order to accomplish this, the valving element 20 is augmented .by a trailing .valve piece or element 78 which is .also aixed to the shaft 22 immediately behind the main valve element 20. The trailing valve element 78 is a flat disc similar .to the valving element 20 but provided with .a plurality of holes 79 drilled through the .piece parallel yto .the axis of the shaft 22. The trailing element 78 is `made to a thickness sufficiently great to throttle the opening of only one of the last opened one of the ports 74, just as .the forward valve element 2li moves .into position to funcover the next port. Fuel may flow into Aeach ,port UDCOvered Yby the forward valve element through .the ,holes 79 (see dotted line position in Figure 7). With such an arrangement very even and gradual increases .0f .fuel output are obtained with the atomizer.

The provision of a trailing valve element 78 .as `shown in Figure 7 permits .the fast opening lof a port 74 4by the leading element 20 without -a rapid jump in .fuel output because the trailing element .is ,simultaneously .closing the previously opened port. A gradual openingor cracking of the port 74 by the valve element 2.0 alone would only produce a drip of fuel .out the .orifice 64 in cases where the orifice is not ,already being supplied with .fuel from another port. This is sov because the fuel does not obtain a sufficient velocity .to atomize-into a spray. However with two valve elements it is .possible to avoid cracking each port. Each newly cut in port may be opened quite rapidly by the leading element 20 and the output will increase only gradually because the trailing element 78 is simultaneously throttling the previously opened port 74.

The invention provides a compact, easily roperable atomizer gun which is capable of atomizing fuel through a plurality of discharge orifices .over an output range varying from a maximum to a minimum of more than to l depending on atolniler .design as .to orice size,- valve element size and port size and spacing. Liquid or fuel may be discharged Vfrom one or more of the orifices in a uniform atomized spray pattern. The first orifice to come into play forms an atomizing spray pattern which remains unchanged as subsequent orifices come into use. it has been found that fuel discharged from subsequent orifices tends to be picked up and carried by the atomizing spray of the first orifice. Any tendency for any one of the subsequent orifices which come into use to depart from the initially established spray angle is .resisted by orifices already functioning.

While a specific embodiment of theinvention has been shown and described in detail to illustrate the application of the invention principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is: 1

1. A liquid atomizer operable at constant liquid supply pressure `over a wide outputrange including a sprayer plate having a plurality of .orifices therein cach V :oinmunicating with individual swirl chambers defined there.- in, said sprayer plate also having .a plurality of liquid delivery .Slots tangentially connected to each of said swirl chambers, conduit means separately connected to each of said liquid delivery slots, a common liquid supply means for said conduit means connected to said conduit means, and valving means separating said-supply means from said conduit means and movable to open each o f said conduit means to said supply means in succession whereby to supply liquid for discharge through each of the .orifices in said sprayer plate in succession.

2. A liquid atomiizer operable at constant liquid supply pressure over a wide .output range including a spray.-V er plate having .a plurality of orifices therein .angularly spaced about a central axis and each communicating with individual swirl chambers defined therein, said .sprayer plate also having a plurality .of liquiddelivery slots tarn gentially connected to .each of said swirl chambers, nor mally closed conduit means separately connected .to the liquid delivery Slots 0f each .of vsaid swirl chambers through which to supply liquid under pressure thereto, means to provide a supply of liquid under constant pressure to said conduit means, and means to open each of Y said conduit means in succession whereby to supply liquid .under pressure for discharge through each ,of .the orifices in said sprayer plate in succession.

3. A liquid atomizer as defined in claim 2, including a valving element coupled to said valving means for closing a previously .opened .Conduit means upon the opening of an additional one of said conduit means whereby to obtain -a .smaller net increase in the total discharge from said atomizer upon the opening of said additional vone of saidconduit means. Y.

.4. A liquid atomizer operable atconstant liquid supply pressure over a wide output range including a sprayer plate having a plurality of orifices .therein uniformly angularly spaced about a central axis and each communicating with individual swirl chambers defined therein, said sprayer plate also having a plurality of liquid delivery slots tangentially connected to each of said swirl chambers, a distributor element connected to said sprayer' plate and having liquid supply passages therein communieating each with at least one of `said delivery slots, normally closed means connected to each of said distributor supply passages, and :means to open each of said normally closed means and said liquid supply passages in succession whereby to supply liquid .under pressure for discharge through yeach of the orifices in said sprayer plate in succession. Y v

5. In an atomizer gun assembly, a variable flow liquid atomizer comprising an elongated hollow body, means connected to one end of lsaid body having a plurality of discharge orifices, Said orifices lying` in a common plane with their discharge axes parallel to each other, Y

means within said atomizer adjacent said orifices defining a plurality of swirl chambers communicating one with each said orifice, and yeach said swirl chamber having a plurality of liquid delivery slots opening tangentially `thereinto, said body having a plurality of liquid delivery passages .extending longitudinally in the walls thereof, there being a passage in communication witheach separate swirl chamber through at least one of said associated swirl chamber delivery slots, said hollow body delining a central bore communicating with said passages through'axially Vand circumferentially displaced radial openings in said walls, a liquid delivery duct communieating with said central bore, and a valving elementfitting closely in said central bore to separate said delivery means from said radial openings, said valving element being slidable axially in said bore to bring said vopen- 'l ings into communication sequentially with said fluid delivery means. Y 1 Y `6. A variable flow liquid atomizer comprising an elongated hollow body, orifice-defining means connecting one end of said body defining a plurality of discharge orifices, said orifices lying in a common plane with their discharge axes parallel to each other, swirl chamber defining means within said atomizer adjacent to said orifice defining means and defining a plurality of swirl chambers communicating one with each said orifice, eachsaid swirl chamber having three liquid delivery slots opening tangentially thereinto, said slots being graduated in depth to provide one small slot and two larger slots of equal dimensions for each said chamber, said hollow body having a plurality of liquid delivery passages extending longitudinally in the walls thereof, there being a separate pair of said passages of different diameter in communication with each separate swirl chamber through the associated swirl chamber delivery slots, the smaller of said pair of passagesbeing in communication with said small slot and the larger of said passages being in communication with said largerslots, said hollow body encompassing a central bore communicating with said passages through axially and circumfereutially displaced radial openings in said walls, a liquid delivery duct communicating with said central bore at said Vopen end of said body and adapted to be connected toa source of tially into communication with said liquid delivery duct.

9. A liquid atomizer operable' at constant liquid sup- -ply pressure overa wide range of fuel `output including 'a sprayer plate havig'f plurality of orifices thereon (angularly spaced about a central -axis and each communicating with individual swirl `chambers defined therein, a hollow distributor defining acentral bore connected toAsa'id sprayer plate and having liquid supply passages therein communicating one with each of said swirl chambers and said discharge orifices, and having ports extending to the central bore thereof at axially displaced Y positions therealong, liquid delivery means communicating with said central bore, and a valving element fitting closely in said central bore and preventing communication of said liquid delivery means with the portion of said bore having said liquid supply passage ports `defined therein, and means to slide said valving element axially :in said bore' to sequentially uncover said ports and to lbring them into communication with said liquid delivery liquid under constant pressure, a valving element fitting closely in said central bore to separate said .delivery duct from said radial openings, said valving element being slidable axially in said bore to bring said openingsjinto Acommunication sequentially with said delivery duct.

7. A variable-flow liquid atomizer comprising in combination, a sprayer plate having a plurality of fixed discharge orifices therein spaceduniformly about said plate,

means defining a plurality of swirl chamberscommunicating .one with each said orifice, each said swirl chamber having a plurality of spaced liquiddelivery slots opening tangentially thereinto, a distributor element cooperable with said means defining said swirl chambers for delivering liquid to said slots and comprising a hollow cylindrical member having a plurality of liquid delivery passages extending Vlongitudinally inY the walls `thereof and terminating in outlet ports in the boregof said distributor element which register'one with each of said slots, liquid delivery means communicating` with said central bore of said distributor element, and a valving element fitting closely in the central bore of said distributor element and covering said radial openingsto separate said delivery means from said radial openings,

said valving element being slidable axially in said bore to sequentially uncover said radial openings-thereby to bring said openings into communication with said liquid delivery means, 1

`8. A variable-dow liquid atomizer comprising in combination, an elongated hollow body, a sprayerplat'e at oneend of said body, said plate having a plurality of fixed spray orifices therein uniformly angularly spaced about a centralaxis of said plate, s aid plate having s Wirl chambers formed therein one adjacent to each said 4orifice, each said swirl chamber haviug'a plurality of spaced liquid delivery slots opening tangentially thereninto, said hollow body having a plurality of liquid delivery passages extending longitudinally therein and terminating in outlet ports which register and communimeans for liquid flow therethrough and discharge through its associated orifice. Y

10. A variable-flow liquid atomizercomprising in combination, a sprayer plate having a plurality of orifices therein, a hollow distributor cooperable with said sprayer plate for deliveringgliquid thereto .and atomizing the liquid, saidV distributor havingV a plurality of liquid de- Ilivery passages extending longitudinally therein and terminating in outlet ports 'which communicate one with each of said orifices, said body distributor having a central Y bore therein communicating with said passages through Aaxially spaced radially extending ports defined, therein,

fiuid deliverylmeans communicating with one end of said central bore, and a valving element includingV a leading portion and a trailing portion spaced fromjsaid leading portion and each fitting closely against the walls of said distributor in the bore thereof,"said leading portion normally completely closing the fuel delivery communicating end of said'distributor, said trailing portion having ia passage therein permitting fluid delivery `communication therethrough tojthespace in said bore between said valve portion s, and meausto move 4said .valve element axially in saidA distributor bore, movement of the leading portion thereof beingeffective first to uncover the nearest one .of said ports and thereby bring said port into communication with said fluid delivery means Y through the passage in saidtrailing portion, and further movement being effective to begin `uncovering the next one of said portsand to bring it into similar communication with said fluid delivery means through the passage .in said trailing portion whilesaid trailing. portion begins covering Vthe 'previously uncovered oneiof said ports, said valving element being slidable axially in said bore there- ,after to sequentiallyuncover all of said radial openings in` succession as the previouslyuncovered one is being 'covered wherebyto bring each into communication sequentially with said fluid delivery means.

i References Cited in the tile of this patent UNiTt-:D srA'rEs PATENTS 1,376,108. 1 Mayeret al. i Apr. 2 6, 1921 f 1,822,047` Leasli Sept. 8, 1931 '42,095,064 fHarper O ct. 5, 1937 '2,162;232 f-Schoenberger June` 13, 1939 2,250,079 McDonald Iu1y 22, 1941 Yoorheis .1 Mar. 30, 1943

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