US3217986A - Nozzle - Google Patents

Description

Nov. 16, 1965 O. A. DAVIS, SR., ETAL NOZZLE 4 Sheets-Sheet 1 Filed March 20. 1964 NOV. 16, 1965 Q A, DAVIS, SR,y ETAL 3,217,986

NOZZLE 4 Sheets-Sheet 2 Filed March 20, 1964 fa. .5A

4 7 TPlVEY Nov. 16, 1965 MDM/15,5@ Em. 3,217,986

f Y \/////4 A. ...l 'il n mail lll/ Nov. 16, 1965 Filed March 20, 1964 O. A.' DAVIS, SR.. ETAL NOZZLE 4 Sheets-Sheet 4 INVENTORS.

@Rv/5 A. DAV/5, 5A? BY BAW/c5 /a WALSH A TTORNEY United States Patent This application is a continuation-in-part of Serial Number 298,970, tiled Iuly 31, 1963, now abandoned.

This invention relates to a novel spray nozzle. More particularly, this invention relates to a burner nozzle adapted for superior admixing of air into an oil spray. Still more particularly, this invention relates to an oil burner nozzle adapted to aspirate atmospheric air into the nozzle and homogeneously admix the aspirated air into the oil spray.

It is advantageous in terms of combustion performance for pressurized oil burner nozzles to aspirate air directly into the burner nozzle. However, pressurized oil burner nozzles which aspirate air directly into the nozzle can advantageously aspirate only a small proportion of the total amount of air required for combustion and in in such nozzles increasing the quantity of air aspirated beyond a speciiic amount does not necessarily further improve nozzle combustion performance. For example,

it is shown in this application that as the quantity of air aspirated into an oil burner nozzle increases in a speciiic range, combustion performance with the nozzle declines.

AThe nozzle of this invention is adapted not only for aspiration of air directly into an oil burner nozzle but also to accomplish this aspiration in a manner which enables the aspirated air to exert a more beneficial effect upon combustion performance.

The nozzle of this invention aspirates one or a plurality of streams of air into a forward nozzle chamber surrounding a swirling conical spray of oil droplets. The air enters the rear of the chamber outside of the periphery of the oil spray. The air approa-ches the -chamber in a generally forwardly direction, rather than from a completely lateral direction. Upon entering the chamber, the aspirated air traverses a relatively Isharp edged obstruction which deiiects the stream laterally, urging it into close proximity with respect to the oil spray. The deflection tends to shift each stream of air laterally in the direction of the oil spray without essentially interfering with the "forward movement of the aspirated air. In this manner, in its forward flow, which is substantially concurrent with respect to the oil spray, the air is `caused to tightly encompass the conical swirling spray of fuel oil droplets so that a supply of air is continuously available for incorporation into the swirling oil spray.

Generally, in order to achieve a high degree of mixing of air into an oil spray, it is necessary to force the air into the oil spray. However, if a jet of air is mixed into a swirling conical oil spray by forcing the air into the oil spray, disruption of swirling and distortion of the shape of the spray is likely. Since a fundamental feature of a swirling spray process is inducing a high degree of oil atomization, interference with the spray in this manner is likely to hinder the atomization procedure. In accordance with this invention, a high degree of mixing of air into an oil spray is achieved with a spray nozzle without interfering with the oil spray pattern or hindering the atomization procedure.

In operation, the nozzle of this invention induces aspirated air to iiow in close proximity to an oil spray. In approaching the oil spray, the aspirated air is deflected laterally so that the air stream closely encompasses the oil spray during its travel. In this manner the oil spray 3,217,986 Patented Nov. 16, 1965 ICC is enclosed by a continuous blanket of air and the air is facilely positioned to be caught up by the swirling droplets in the oil spray to provide a homogeneous admixture of oil and air with minimum disturbance of the oil spray.

This invention and the advantages thereof are illustrated by the following description in reference to the drawings in which:

FIGURE l is a cross-sectional view of the nozzle of this invention modified to show two tangential slots 44 in full View, and taken along the line 1--1 of FIGURE 2,

FIGURE 2 is a plan of member 14 of FIGURE l,

FIGURES 3A and 3B are cross-sectional views of fragments of corresponding nozzles, the view of each nozzle being modified to show two tangential slots 44 in full, with FIGURE 3A showing a nozzle of this invention and FIG- URE 3B showing a deviation therefrom for the purpose of demonstrating the advantage of the nozzle of this invention,

FIGURE 4 shows graphs illustrating the results of combustion tests obtained with the nozzles of FIGURES 3A and 3B,

FIGURES 5A and 5B are cross-sectional views of fragments of different nozzles, the view of each nozzle being modiiied to show two tangential slots 44 in full, with FIGURE 5A showing a nozzle of this invention and FIG- URE 5B showing a deviation therefrom for the purpose of demonstrating the advantage of the nozzle of this invention,

FIGURE 6 is a cross-sectional view of another nozzle of this invention,

FIGURE 7 is a cross-sectional view indicated by the line 7-7 of the nozzle of FIGURE 6 showing the forward end of member 74 in full, and

FIGURE 8 is a cross-sectional view of the most preferred nozzle of this invention.

Referring to FIGURE 1, nozzle 10 is comprised in part of three coaxial concially shaped elements including an inner cone 12, an intermediate cone 14, and an outer conical housing 16. Conical surface 18 of inner cone 12 and conical surface 20 of intermediate cone 14 abut firmly against each other in fluid tight engagement while conical surface 22 of intermediate cone 14 :and conical surface 24 of outer conical housing 16 also abut iirmly against each other in fluid tight engagement. The rearward portion of inner cone 12 comprises a stud 26 having a passageway means 28 extending axially and radially to zone 34. A conically shaped axial swirl chamber 30 is defined between inner cone 12 and intermediate cone 14. One or a plurality of shallow slots 32 extend the length of conical surface 18 connecting zone 34 and swirl chamber 30. Slots 32 approach swirl chamber 30 in a direction which is substantially tangential with respect to the swirl chamber wall surface. A central opening at the forward end of intermediate cone 14 `delines an axial discharge orifice 36 for swirl chamber 30 leading into a second or forward chamber 38.

Second chamber 3S comprises a cylindrically shaped bore extending axially completely through outer conical housing 16. The base portion of second chamber 38 is not coincident with but rather is removed from conical surface 24 by means of a continuoues ledge 40 lying on a plane substantially normal to the longitudinal axis of nozzle 10. The interior surface of ledge 40 is coincident at one end with conical surface 24 and terminates at the other end with a relatively sharp edge 42, for example, the right angle shown. Sharp edge 42 extends along a continuous circular path and defines the periphery of the base of forward chamber 38. Slots 44 extend from zone 46 and open into the base of forward chamber 3S. The depth of slots 44 can be tapered along the length of the slots, as shown, or the depth of slots 44 can equivalently be uniform along the length of the slots. Ledge 40 is a partial barrier and partially obstructs the front or discharge end of slots 44 by covering the portion of the terminus of slots 44 which is remote from orifice 36. Ledge 40 is sufficiently wide in relation to the depth of slots 44 at their juncture with second chamber 38 that it constitutes a significant effect upon flow therefrom. For example, ledge 40 may obstruct about one third, one half, or more, of the portion of the forward opening of slots '44 most remote from orice 36. This estimate is merely illustrative and the extent of obstruction of the terminus of air slots 44 by ledge 40 can vary widely depending upon the desired operating characteristics of the nozzle.

One or more slots 44 are provided. Slots 44 enter the bottom of forward chamber 38 in a generally forward direction, as shown in FIGURE 1, and also in a direction which is substantially tangential with respect to curved wall 48, as is shown in FIGURE 2. Orifice 36 enters chamber 38 axially at the base thereof. A swirling conical spray of oil droplets 50 from orifice 36 traverses the length of forward chamber 38 and leaves the nozzle through discharge opening 52 of forward chamber 3S. Opening 52 is larger than orifice 36. The depth and diameter of forward chamber 38 is determined by the included angle of spray 50 and is such that the spray 50 passes close to but does not impinge upon the periphery of opening 52.

Nozzle includes an outer nozzle body 54 having opening means 56 extending from the atmosphere to zone 46. The nozzle elements are secured fixedly into position by means of threaded member 58 and threaded member 60. Member 58 has an axial bore 62 in register with passageway means 28. Member 58, member 60 and outer nozzle body 54 are in threaded engagement, as shown, when the nozzle is assembled. Member 58 is threaded over its entire length to permit connection to a source of pressurized fuel oil and nozzle body 54 is provided with threads for mounting the nozzle during opera* tion.

In the operation of the nozzle of FIGURE 1, oil under pressure is pumped through axial passageways 62 and 28 into zone 34, whence it passes through slots 32 Which enter swirl chamber 30 in a forwardly and tangential manner with respect to the conical wall surface of swirl chamber 30. A thin film of swirling oil is discharged through orifice 36 which diverges conically in transit through forward chamber 38 and disintegrates into very small oil droplets.

Forward chamber 38 serves as both an air aspirating and air-oil mixing chamber. r[he relative depth and diameter dimensions of forward chamber 38 are determined by the included angle of conical oil spray 50. These dimensions are established so that oil spray 50 narrowly misses the forward edge of wall 48. In this manner, a suction is created within forward chamber 38 which draws atmospheric air through openings 56, zone 46 and elongated passageways 44. If oil spray 50` impinges upon wall 48, the nozzle drips liquid oil, aspiration fails, and

vthe nozzle becomes inoperative for practical purposes.

Also, if oil spray 50 clears the outer edge of Wall 48 by too great a distance, the nozzle will be incapable of effective aspiration.

When the depth and diameter dimensions of chamber 38 are established in relation to the included angle of spray 50 so that spray 50 clears wall 48 by an amount resulting in substantially optimum aspiration, a stream of air fiows forwardly through elongated passageways 44, past sharp edge 42, and into forward chamber 38. In passing sharp edge 42., the aspirated air is detiected so that as it enters forward chamber 38 it is urged close to oil spray 50, as indicated at S1. The air defiecting function of sharp edge 42 causes aspirated-air -stream 51 to be deflected laterally so that it closely encompasses oil spray 50 without disturbing the spray or hindering oil atomizaltion. Air stream 51 travels with the spray in close proximity thereto so that the air is facilely available to be caught up by the oil spray to provide a homogeneous admixture of oil and air with minimum disturbance of the oil spray.

FIGURE 1 shows that the diameter of forward chamber 38 is sufficiently large not only for conical spray 5f) to pass through without contact with the walls of forward chamber 38 but also for the air stream vena contracta indicated at 51 to develop around conical spray Si);

The air defiecting function of sharp edge 42 provides greatly improved combustion performance. In a nozzle which is otherwise incapable of inducing a high velocity in the aspirated air stream, both the number and the size of air passageways 44 are advantageously relatively small in order to maintain a relatively high air velocity through each of these passageways. A relatively high air velocity in the region of sharp edge 42 is necessary if sharp edge 42 is to function as an orifice and adequately deiiect air stream 51 in the direction of oil spray 50. In a nozzle wherein the velocity of the aspirated air is not great, it is advantageous to minimize the number and size of air passageway slots 44 even to the extent of severely restricting the total volume of air aspirated by the nozzle, since the higher air velocity which results thereby induces a higher degree of air deflection with ensuing improved air-oil mixing.

The highly superior mode of mixing air and oil provided by the nozzle of this invention produces better combustion characteristics than is possible by merely aspirating a greater quantity of air in the absence of the superior mode of mixing. Data presented below show that in a nozzle devoid of the air deliecting means of this invention, a mere increase in the quantity of air aspirated does not necessarily improve combustion performance and, in fact, can hinder combustion performance. In contrast, superior combustion performance occurs as a result of the more thorough admixing with oil of a relatively small volume of aspirated air which is accomplished by employing, in combination, a forward chamber 38 in which the depth and diameter dimensions are conducive to optimum air aspiration for superior mixing of air and oil, together with one or a plurality of air slots 44, each of relatively small cross section to provide a high air velocity therein, and a sharp edge 42 at the discharge terminus of the air slots 44.

Tests were conducted to illustrate the advantage during combustion of the sharp edge air deflecting means 42. A first combustion test was made employing a nozzle generally similar to the nozzle of FIGURES 1 and 2 and having the specific construction as shown in FIGURE 3A, including a sharp edge 42 disposed at the discharge end of passageway means 44. Passageway means 44 approaches second chamber 38 in both a forwardly and a tangential manner. At the conclusion of the first combustion test, the nozzle of FIGURE 3A was modified for use in a second combustion test by eliminating sharp edge 42 by machining, as shown in FIGURE 3B. Except for this single change, the nozzle of FIGURE 3B is identical to the nozzle of FIGURE 3A and all conditions, including oil pressure, were otherwise held uniform in each test. The results of these tests are shown in the curves of FIGURE 4.

The curves of FIGURE 4 show the results of the combustion tests employing the nozzle of FIGURE 3A and the nozzle of FIGURE 3B in the form of a graph of smoke spot number versus percent carbon dioxide in a sample of flue gas produced during combustion with each ynozzle in accordance with the method described in ASTM Standards on Petroleum Products, 1960, page 1041. For purposes of analyzing the test results, it is noted that best combustion results are indicated by the combination of a high carbon dioxide content, indicating a high degree of combustion, and a low smoke content. While the percent of carbon dioxide can be increased by reduction of air input, this will have the adverse effect of increasing smoke content. On the other hand, smoke content can be decreased by merely admitting a large excess of air but this will have the adverse effect of greatly diminishing the relative content of carbon dioxide. Optimum results are achieved with the combination of relatively high carbon dioxide content and relatively low smoke content.

Referring to FIGURE 4, at the steep slope of the curves, it seen that at any particular percentage of carbon dioxide in the flue gas the lowest smoke content is achieved with the nozzle of FIGURE 3A having sharp edge air detlccting means 42. Therefore, the removal of sharp edge air detlecting means 42, as shown in the nozzle of FIGURE 3B, resulted rin increased smoke content at any particular percentage of carbon dioxide or, conversely, a lower percentage of carbon dioxide at any particular smoke level.

Another series of tests was conducted to demonstrate the ability of the sharp edge air How dellector of the invention to induce superior combustion characteristics `as compared to the combustion characteristics achieved by similar nozzles which are devoid of the air ilow deflector, even nozzles which actually aspirato a greater quantity of air at a given fuel ilow rate. The nozzles utilized in these tests are shown in FIGURES 5A and 5B. FIGURE 5A shows a nozzle having a sharp edge 42 and having a forward chamber 38 whose depth, designated as L, is 0.030 inch and whose diameter, designated as D, is 0.089 inch. These dimension-s show that the diameter of forward chamber 38 is greater than its` length. The reason the diameter of forward chamber 38 is greater than its length is that if L were as great as D the conical oil spray would impinge upon the walls of forward chamber 38, as is clear from observation of FIGURE 5A. Air slots 44 approach second chamber 38 in a substantially forwardly and tangential direction. As shown in FIGURE 5A, the surface of discharge orifice 36 is curved and tapers outwardly in the direction of forward chamber 38 and is in direct communication with forward chamber 38 for discharging a distinctly conical spray from swirl chamber 30 through forward chamber 38 without interference, obstruction, or contact with any part of said nozzle. The oil spray issuing from orifice 36 of oil swirl chamber 30 had a 70 degree included angle and was found to exert a suction upon tangential air passageways 44 equivalent to 0.6 inch of water. As shown in Table 1, the flue gas from the nozzle of FIGURE 5A contained 12.7 percent carbon dioxide at a smoke spot number of l.

FIGURE 5B shows another nozzle used in the same series of tests. The nozzle of FIGURE 5B is similar to the nozzle of FIGURE 5A except that the passageways 44 are each devoid of sharp edge 42 and except that its forward chamber 38 has certain L and D dimensions which are slightly different than those of the nozzle of FIGURE 5A. The oil pressure and included angle of the oil spray in the tests with the nozzle of FIGURE 5A were the same as in the tests with the nozzle of FIGURE 5B. The nozzle of FIGURE 5B was utilized in two tests in which the D dimension was 0.089 inch and 0.101 inch, respectively. The results of these tests are shown in Table l.

It is seen from Table l that the aspirational suction exerted at air slots 44 of the nozzle tested of FIGURE 5B varied considerably with dimension changes in the second chamber, It was also seen from Table l that, in the tests made, an increase in air aspiration did not produce a corresponding improvement in combustion performd ance. In fact, the nozzle =of FIGURE 5B which exerted an aspirational elfect of only 0.3 inch of water was superior, in terms of combustion performance, to the other nozzle of FIGURE 5B which exerted ten times its aspirational effect upon atmospheric air. Table l also shows that better combustion performance was achieved with the nozzle of FIGURE 5A, equipped with sharp edge 42 at the air passageways, than was achieved with either of the nozzles 4of FIGURE 5B, even though one of the nozzles of FIGURE 5B exerted a much greater aspirational suction upon atmospheric air. Table l shows that sharp edge 42 exerts an influence upon combustion performance independent of the amount of air aspirated.

Combustion tests were made to determine the effect of air deflector 42 when air was pumped through air slots 44 under a small pressure, such as l or 2. pounds per square inch gauge. These tests showed combust-ion results are also improved by the provision of `sharp edge air deflector 42 when air is pumped under pressure through air slots 44.

FIGURES 6 and 7 illustrate a modilied nozzle 70 of this invention. FIGURE 6 shows an inner member 72, an intermediate member 74, and an outer member 76. Outer member 76 comprises the body of the nozzle. Inner member 72 an-d intermediate member 74 have facing conical surfaces in engagement while intermediate member 74 and outer member 76 have flat facing surfaces in engagement. The various facing surfaces are urged into fluid tight engagement with each other by means of plug 78 which is in threaded engagement with nozzle body 76. Oil enters zone 82 through oil passages 80 in plug 78 whence it travels through slots 84 which enter swirl chamber 86 in a forwardly and tangential direction with respect to the conical wall surface thereof. A diverging, conical, swirling spray 88 of atomized oil droplets leaves axial swirl chamber discharge orifice 90.

Oil spray 88 clears wall 92 defining the lforward nozzle chamber by an amount adapted to aspirate atmosphere air through a plurality of atmospheric air openings 94 which have access to a continuous air zone 96. Each air opening 94 is in general register with an arc-like groove 98 cut in intermediate member 74. As shown in FIGURE 7, each groove 98 extends to the forward nozzle chamber in a generally forward and nontangential direction.

Although each groove 98 could also extend to the second chamber in a generally forward and tangential direction with respect `to forward chamber wall 92, a forward but nontangential direction is preferred. The front of nozzle body 76 is directed inwardly tto form a continuous circular ledge 100 having a sharp right angle edge 102 at its interior face which partially obstructs the portion of each groove 98 remote from orifice 90 in the region of the juncture of each groove 98 with the forward nozzle chamber. Sharp edge 102 causes aspirated air to be deflected, as indicated at 104, so that each air stream is urged laterally against oil spray 88. The air flow deflection caused by sharp edge 102 causes fthe air streams to encompass oil spray 88 so that the swirling spray of oil droplets can accept the concurrently flowing air and become homogeneously admixed therewith without disruption of the oil spray.

FIGURE 8 shows a cross-sectional View of nozzle 110, which is the most preferred nozzle of this invention. In nozzle 110, a hollow, swirling, diverging oil spray 112 issuing from rst orice 114 narrowly clears the downstream end of second chamber 116 and thereby aspirates atmospheric air inwardly through a plurality of radial passageways 118. Air passageways 118 lead into a continuous annulus 120 which completely surrounds conical member` 122. Air drawn inwardly through passageways 118 flows into annulus 120, and thence flows past sharp right angle edge 124 which causes i't to be deflected toward the oil spray 112, as is shown in FIGURE 8. FIG- URE 8 shows that the outer conical surface of member 122 is continuous with and tapers rearwardly and outwardly substantially conically from the curved and tapered surface of discharge orifice 114 toward the rearward end of anulus 120 with the forwardmost projection of the outer conical surface of member 122 being substantially at the curved and tapered surface of the discharge orifice so that an aspirated air stream drawn inwardly through passageways 118 and annulus 120 can approach discharge orifice 114 from the rear along the outer conical surface of member 122 and can closely encompass oil spray 112 directly upon discharge of said oil spray from discharge orifice 114.

It is noted in regard to nozzle 110 of FIGURE 8 that oil discharge orifice 114 is disposed rearwardly with respect to the rearward end of second chamber 116. This structure provides an important functional advantage because the portion of oil spray 112 closest to orifice 114 comprises a substantially continuous swirling film of oil. However, this film tends to quickly disintegrate, resulting in atomization into a great plurality of very small `oil droplets. Y By virtue of the fact that oil discharge orifice 114 is disposed to the rear of sharp edged corner 124, oil spray 112 has a chance to become atomized before reaching the vicinity of sharp edge 124 and therefore before reaching the zone wherein it becomes admixed with the air stream deflected toward it by sharp edged corner 124. Since the oil is accorded an opportunity to become atomized before the aspirated air is deflected itoward it, a high degree of admixture of air and oil is achieved. On the other hand, if oil discharge orifice 114 were disposed on the same plane with or forwardly with respect to air deflecting edge 124, the air passing edge 124 would be deflected into an incompletely atomized film of oil and therefore could not admix as intimately and thoroughly with the oil spray, in which case the effectiveness of sharp edge 124 would be sharply diminished. In an actual test a marked improvement in combustion performance was achieved by disposing oil discharge orifice 114 about .O15 inch to the rear of the plane of sharp edge 124, as compared to the observed combustion performance when the oil discharge orifice was disposed on the same plane as the sharp edge.

It is important that air passageways 118 enter continuous annulus 120 at a position therein which is decidedly to the rear lof the plane on which sharp edged corner 124 lies. Air passageways 118 should preferably enter annulus 120 at a position as close as possible to the rear of annulus 120 and should have a relatively small width so that air only enters annulus 120 near the rearward end of said annulus. This permits the aspirated air to travel in a forwardly direction past sharp edge 124 permitting sharp edged corner 124 to function as a sharp edged orifice plate. The forward =or axial component of movement of air past sharp edge 124 permits sharp edge 124 to function as an orifice plate, defiecting the air stream and forming the vena contracta 126. On the other hand, if air passageway 118 were disposed on about the same plane as sharp edge 124, the aspirated air would approach sharp edge 124 from a direction which is substantially completely lateral with little `or no forward or axial component of movement, thereby preventing formation of a vena contracta.

An advantageous feature of nozzle 110 is that air passageways 118 approach annulus 120 in a radial rather than a tangential direction. A .tangential approach would impart `swirling to the aspirated air and the centrifugal force fof a swirling air stream passing through second chamber 116 would tend to fling the air away from the oil spray, thereby counteracting the effect of sharp edge 124 which is to defiect the aspirated air toward the oil spray.

Another advantageous structural feature of nozzle 110 is that the individual air passageways 113 each lead into a common annulus 120, which annulus 120 is bounded by sharp edged corner 124. In this manner a circumferentially uninterrupted lstream of air is deliected toward and encompasses the oil spray providing a uniform admixture of air and oil, thereby -insuring a uniform flame. In contrast, if continuous annulus were absent and each air passageway 118 individually approached sharp edged corner 124, a plurality of streams of air would be deected toward the oil spray rather than a circumferentially continuous blanket of air. A plurality of individual jets of air would produce alternate air-rich and air-lean streaks in the oil spray and consequently could produce a nonuniform iiame. `Continuous annulus 120 is advantageously utilized in a nozzle in which the velocity of aspirated air through even an enlarged annulus is sufficiently high that sharp edge 124 can induce a vena contracta, while a plurality of individual air passages, as is shown in FIGURES 1 and 6, is required to produce individual high Velocity air jets where the velocity of the total stream of aspirated air fiowing in an enlarged annulus would not be sufficiently high for a sharp edge to induce a pronounced vena contracta.

We claim:

1. A burner nozzle comprising axial swirl chamber means, second axial chamber means of substantially cylindrical configuration disposed forwardly with respect to said swirl chamber means, said swirl chamber means having at its forward end axial discharge orifice means with the surface of said discharge orifice means being curved and tapered outwardly in the direction of said second chamber means and being in unobstructed communication with said second chamber means for discharging a swirling distinctly conical oil spray from said swirl chamber means through said second chamber means without interference or obstruction and without substantial Contact with said nozzle so that said conical oil spray aspirates a stream of air through said second charnber means from the rearward end to the forward end thereof, air passageway means whose rearward end is open to the exterior of said nozzle and Whose forward end is open to said `second chamber means for channeling air into said second chamber means, surface means defining said air passageway means which is continuous with and tapers rearwardly and outwardly from said curved and tapered surface of said discharge orifice means toward the rearward end of said air passageway means with the forwardmost projection of said surface means being substantially at the curved and tapered surface of said axial discharge orifice for permitting said stream of air to approach said discharge orifice from the rear and closely encompass the oil spray directly upon discharge of said oil spray from said discharge orifice, ow deflecting means having a relatively sharp edge which is exposed to said air passageway means near the juncture of said air passageway means and said second chamber means in the region of said air passageway means remote from said swirl chamber discharge orifice means for inducing a vena contracta in said aspirated air stream which deflects the aspirated air stream into said conical spray, said .cylindrical second chamber means having a diameter which is substantially greater than the length thereof and which is sufficiently large for both the conical spray from the swirl chamber means to pass through without substantial contact with the walls of said second chamber means and for the air stream vena contracta to develop around said conical spray.

2. The nozzle of claim 1 wherein said flow defiecting means is defined by a relatively sharp edged right angle juncture between the forward end of said air passageway means and the rearward end of said second chamber means.

3. The nozzle of claim 1 wherein said air passageway means extends to said second chamber means in a substantially forwardly direction.

4. The nozzle of claim 1 wherein said swirl chamber discharge orifice means is disposed substantially at the rearward end of said second chamber means.

5. The nozzle of claim 1 wherein said swirl chamber discharge orifice means is disposed substantially at the rearward end of said second chamber means and said air passageway means is a continuous annulus.

6. The nozzle of claim 1 wherein said surface means defining said air passageway means is conical.

7. The nozzle of claim 1 wherein said surface means defining said air passageway means is conical and said air passageway means is a continuous annulus.

8. The nozzle of claim 1 wherein said swirl chamber discharge orifice means is disposed rearwardly with respect to the rearward end of said second chamber means.

9. The nozzle of claim 1 wherein said swirl chamber discharge orifice means is disposed rearwardly with respect to the rearward end of said second chamber means, said surface means defining said air passageway means is conical, and said air passageway means is a continuous annulus.

10. The nozzle of claim 1 wherein said air passageway means is defined by slot means.

11. The nozzle of claim 10 wherein said slot means enters said second chamber means in a substantially tangential direction.

12. A burner nozzle comprising inner, intermediate and outer members, axial swirl chamber means defined by said inner and intermediate members, air passageway means defined by said intermediate and outer members, the rearward end of said air passageway means exposed to the exterior of said nozzle, axial swirl chamber discharge orifice means defined at the forward end of said intermediate member, said outer member inturned at its forward end to define axial forward chamber means of substantially cylindrical configuration the rearward end of which defines sharp edge fiow deflecting means, said swirl chamber discharge orifice means disposed in the region of the rear of said forward chamber means, the surface of said discharge orifice means being curved and tapered outwardly in the direction of said forward chamber means and being in unobstructed communication with said forward chamber means for discharging a swirling distinctly conical oil spray from said swirl chamber means through said forward chamber means without interference or obstruction and without substantial contact with said nozzle so that said conical oil spray aspirates a stream of air through said air passageway means and said forward chamber means, surface means on said intermediate rnember defining said air passageway means which is continuous with and tapers rearwardly and outwardly from said curved and tapered surface of said discharge orifice means toward the rearward end of said air passageway means with the forwardmost projection of said surface means being substantially at the curved and tapered surface of said axial discharge orifice means for permitting said stream of air to approach said discharge orifice from the rear and closely encompass the oil spray directly upon discharge of said oil spray from said discharge orifice, said sharp edge flow defiecting means defining the juncture between said forward chamber l@ means and said air passageway means remote from said discharge orifice means for inducing a vena contracta in said aspirated air stream which defiects the aspirated air stream into said conical spray, said cylindrical forward chamber means having a diameter which is substantially greater than the length thereof and which is sufficiently llarge for both the conical spray from the swirl chamber means to pass through without substantial contact with the walls of said forward chamber means and for the air stream vena contracta to develop around said conical spray.

13. The nozzle of claim 12 wherein said swirl chamber discharge orifice means is substantially at the rearward end of said forward chamber means.

14. The nozzle of claim 12 wherein said swirl chamber discharge orifice means is substantially at the rearward end of said forward chamber means and said air passageway means is a continuous annulus between said inter mediate and outer members.

15. The nozzle of claim 12 wherein the outer surface of said intermediate member is conical.

16. The nozzle of claim 12 wherein the outer surface of said intermediate member is conical and said air passageway means is a continuous annulus between said intermediate and outer members.

17. The nozzle of claim 12 wherein said swirl chamber discharge orifice means is disposed rearwardly with respect to the rearward end of said forward chamber means.

18. The nozzle of claim 12 wherein said swirl chamber discharge orifice means is disposed rearwardly with respect to the rearward end of said forward chamber means, the outer surface of said intermediate member is conical, and said air passageway means is a continuous annulus between said intermediate and outer members.

19. The nozzle of claim 12 wherein said sharp edge is a right angle sharp edge.

20. The nozzle of claim 12 wherein said air passageway means extends to said forward chamber means in a relatively forwardly direction.

21. The nozzle of claim 12 wherein said air passageway means is defined by slot means in the outer surface of 'said intermediate member.

22. The nozzle of claim 21 wherein said slot means enters said forward chamber means in a substantially tangential direction.

References Cited by the Examiner UNITED STATES PATENTS 1,43 9,320 12/ 1922 Morse 239-403 1,796,131 3/1931 Szodomka Z39-431 1,904,509 4/1933 Morse Z39-403 2,551,276 5/1951 McMahan 239--403 2,719,056 9/ 1955 Bettison 239-403 FOREIGN PATENTS 702,215 l/ 1954 Great Britain.

EVERETT W. KIRBY, Primary Examiner.

Claims (1)

1. A BURNER NOZZLE COMPRISING AXIAL SWIRL CHAMBER MEANS, SECOND AXIAL CHAMBER MEANS OF SUBSTANTIALLY CYLINDRICAL CONFIGURATION DISPOSED FORWARDLY WITH RESPECT TO SAID SWIRL CHAMBER MEANS, SAID SWIRL CHAMBER MEANS HAVING AT ITS FORWARD AND AXIAL DISCHARGE ORIFICE MEANS WITH THE SURFACE OF SAID DISCHARGE ORIFICE MEANS BEING CURVED AND TAPERED OUTWARDLY IN THE DIRECTION OF SAID SECOND CHAMBER MEANS AND BEING IN OBSTRUCTED COMMUNICATION WITH SAID SECOND CHAMBER MEANS FOR DISCHARGING A SWIRLING DISTINCTLY CONICAL OIL SPRAY FROM SAID SWIRL CHAMBER MEANS THROUGH SAID SECOND CHAMBER MEANS WITHOUT INTERFERENCE OR OBSTRUCTION AND WITHOUT SUBSTANTIAL CONTACT WITH SAID NOZZLE SO THAT SAID CONICAL OIL SPRAY ASPIRATES A STREAM OF AIR THROUGH SAID SECOND CHAMBER MEANS FROM THE REARWARD END TO THE FORWARD END THEREOF, AIR PASSAGEWAY MEANS WHOSE REARWARD END IS OPEN TO THE EXTERIOR OF SAID NOZZLE AWND WHOSE FORWARD END IS OPEN TO SAID SECOND CHAMBER MEANS FOR CHANNELING AIR INTO SAID SECOND CHAMBER MEANS, SURFACE MEANS DEFINING SAID AIR PASSAGEWAY MEANS WHICH IS CONTINUOUS WITH AND TAPERS REARWARDLY AND OUTWARDLY FROM SAID CURVED AND TAPERED SURFACE OF SAID DISCHARGE ORIFICE MEANS TOWARD THE REARWARD END OF SAID AIR PASSAGEWAY MEANS WITH THE FORWARDMOST PROJECTION OF SAID SURFACE MEANS BEING SUBSTANTIALLY AT THE CURVED AND TAPED SURFACE OF SAID AXIAL DISCHARGE ORIFICE FOR PERMITTING SAID STREAM OF AIR TO APPROACH SAID DISCHARGE ORIFICE FROM THE REAR AND CLOSELY ENCOMPASS THE OIL SPRAY DIRECTLY UPON DISCHARGE OF SAID OIL SPRAY FROM SAID DISCHARGE ORIFICE, FLOW DEFLECTING MEANS HAVING A RELATIVELY SHARP EDGE WHICH IS EXPOSED TO SAID AIR PASSAGEWAY MEANS NEAR THE JUNCTURE OF SAID AIR PASSAGEWAY MEANS AND SAID SECOND CHAMBER MEANS IN THE REGION OF SAID AIR PASSAGEWAY MEANS REMOTE FROM SAID SWIRL CHAMBER DISCHARGE ORIFICE MEANS FOR INDUCING A VENA CONTRACTA IN SAID ASPIRATED AIR STREAM WHICH DEFLECTS THE ASPIRATED AIR STREAM INTO SAID CONICAL SPRAY, SAID CYLINDRICAL SECOND CHAMBER MEANS HAVING A DIAMETER WHICH IS SUBSTANTIALLY GREATER THAN THE LENGTH THEREOF AND WHICH IS SUFFICIENTLY LARGE FOR BOTH THE CONICAL SPRAY FROM THE SWIRL CHAMBER MEANS TO PASS THROUGH WITHOUT SUBSTANTIAL CONTACT WITH THE WALLS OF SAID SECOND CHAMBER MEANS AND FOR THE AIR STREAM VENA CONTRACTS TO DEVELOP AROUND SAID CONICAL SPRAY.

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