US2710229A

US2710229A - Spray nozzle

Info

Publication number: US2710229A
Application number: US164202A
Authority: US
Inventors: Joseph M Patterson
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1950-05-25
Filing date: 1950-05-25
Publication date: 1955-06-07
Anticipated expiration: 1972-06-07

Description

June 7, 1955 J. M. PATTERSON 2,710,229

SPRAY NOZZLE Filed May 25. 1950 Inventor JOSEPH Mg PA TTERSO/V.

' Cttorncg United States Patent U SPRAY NOZZLE Joseph M. Patterson, Lansing, Mich., assignor to Food Machinery and Chemical Corporation, San Jose, Calif., a corporation of Delaware Application May 25, 1950, Serial No. 164,202

4 Claims. (Cl. 299-140) The present invention relates to spray nozzles, and more particularly to a shear type spray nozzle for mounting in an air stream for producing air-borne spray.

An object of the present invention is to provide an improved shear nozzle for mounting in a high velocity air stream.

Another object is to provide a simple and effective device for feeding spray particles into an air blast.

Another object is to provide a spray nozzle wherein spraying liquid is supplied to the nozzle at relatively low pressure through a relatively large orifice and the spray particles are created by the shearing action of a high velocity air blast in which the nozzle is located.

Another object is to provide a shear nozzle for mounting in an air blast, with an end of the nozzle where the shearing action occurs sloped to diverge from the direction of air flow past the nozzle.

Another object is to provide a shear nozzle in which the amount of liquid fed therethrough can be varied between relatively wide lirnits without materially changing the size range of spray particles produced thereby.

These and other objects and advantages of the present invention will be apparent from the following description and the accompanying drawings, wherein:

Fig. 1 is a perspective view of a shear nozzle embodying the invention mounted on a fragment of manifold pipe, portions being broken away.

Fig. 2 is a section taken along the mid-plane of the nozzle indicated by the line 22 of Fig. 1.

Fig. 3 is a fragmentary perspective view showing spray nozzles embodying the invention mounted at the air blast outlet of a' radial discharge type of spraying machine.

Fig. 4 is a fragmentary longitudinal section through an air blast tube of an axial discharge type of spraying machine, with a spray nozzle embodying the invention mounted therein.

The shear nozzle of the present invention is adapted to be mounted in any suitable high velocity air stream, but for the purpose of the present specification it will be described as mounted either in the air blast from a radial discharge type of sprayer of the type disclosed in Patent 2,476,960 to George W. Daugherty, issued July 26, 1948, as illustrated in Fig. 3 of the present drawings, or in that from an axial discharge type of sprayer of the type disclosed in patent application of George W. Daugherty, Serial No. 28,317, filed May 21, 1948, now Patent No. 2,667,717, as illustrated in Fig. 4 of the present drawings.

In the embodiment of the invention illustrated in Figs. 1, 2 and 3 a combined nozzle-support and liquid-supply tube has one end thereof screwed into an adapter bushing 11 which in turn is screwed into a side outlet 12 of a liquid supply manifold 13. The assembled length of the tube 10 and bushing 11 should be such as to locate the nozzle in a desired part of the air stream. The manifold 13 is arranged adjacent the air blast outlet 14 (Fig. 3) of a radial discharge sprayer 15 of the type disclosed in Daugherty Patent 2,476,960 mentioned previously herein.

Patented June 7, 1955 Each tube 10 is internally threaded on its free end, and an orificed fitting 18, with threaded end portions 19 and 20 (Fig. 2) and an intermediate nut portion 21 formed integrally therewith, is screwed into the free end of the tube 10. The fitting 18, which may be considered as part of the nozzle, has a jet orifice 22 therein of a predetermined but relatively large diameter, for example, in the range between three sixty-fourths and one-eighth of an inch. Liquid discharged through this orifice is directed axially of the fitting toward the opposite wall of a nozzle head 23.

The head 23 is tubular, and is herein illustrated as being substantially circular in cross sectional shape, although the use of other shapes, such as rectangular, triangular, oval and so-called streamlined section, is contemplated. One or both

ends

24 and 25 of the tubular head portion are exposed to the air stream and are sloped to diverge from the direction of How of the air stream in which the nozzle is mounted. The head 23 has a threaded hole 28 therethrough midway of the length of a side thereof, into which is screwed the threadedouter end of the fitting 18.

The amount of divergence of the end faces 24 and 25 of the head portion 23 from the direction of air flow materially affects the performance of the nozzle. For example, it has been found by experiment that with a jet orifice having a diameter Within the range from three sixty-fourths to one-eighth of an inch, a pressure of sixty pounds per square inch on the spraying liquid supplied to the nozzle, an air blast velocity at the nozzle of approximately ninety miles per hour, and the planes of the

sloping ends

24 and 25 of the head 23 disposed to diverge at angles of fifty-five degrees in the direction of air flow past the nozzle, the spray particle size will be between 30 and microns.

Since such a wide variation in orifice sizes at the above specified constant pressure would produce a wide variation in volume output of spraying liquid, it is important to note that the spray particle size range remains quite constant throughout such variation. Further experments indicate that best nozzle performance results are obtained when the end faces 24 and 25 of the head divergefrom the direction of air flow past the nozzle at angles within the range between fifty and seventy degrees.

The threaded hole 28 in the tubular head portion 23 to receive the jet fitting 18 is so located that the longer side of the head portion will be on the downstream side of the nozzle. Therefore, when, as shown in Fig. 4, a support and liquid supply tube 10a and jet fitting 18a are mounted in a tubular air tunnel 29 with their common axis extending in the direction of flow of the air stream, the jet fitting will be screwed into a threaded hole provided therefor in the short or upstream side of the head 23a. This disposes the sloping end faces 24a and 25a of the head 23a at divergent angles to the direction of air flow past the nozzle.

All threads in the form of the invention illustrated are of the tapered or iron pipe type so that the parts can be drawn down into frictionally secured relation to each other, and still be capable of being removed and replaced as required.

Briefly, the operation of the device is as follows: The shear nozzle is mounted with the longer side of the head 23 on the downstream side of the air blast on a fitting 18 having an orifice 22 of predetermined size therein. The volume of liquid supplied by the nozzle can be varied either by changing the orifice size, or by varying the pressure'on the liquid supplied to the nozzles. Usual air blast generating means, not shown, such as a suitable motor driven blower or fan, is then placed in operation to discharge a high velocity air blast past the nozzle,

n the sp ying l q id. is discharged unde prede ermined pressure into the head 23 through the jet orifice 22.

The jet of liquid discharged through the orifice 22 r k the h d oppos t the f t ne 13, he the dr vi g force of the jet causes the liquid to spreadradially in all directions from the point of impact as a center wi h a force much greater than the force of gravity, with the result that the liquid is spread over the inner wall of the head 23, and is caused to flow toward the diagonally diverging

head ends

24 and 25. Here the air blast shears oil. particles of liquid both on the short or upstream edge portions 241) and 25b of the sloping ends of the head, and also on the longer downstream edges 24c and 25c thereof. The diagonal slope of the ends of the head 23 provides an offsetting of the upstream and downstream edges thereof to expose both of them to the shearing action of the air blast. It also provides a sharpened or chisel-like edge on the downstream sides of both of said edge portions. This sharpened, chisel-like edge structure insures that the film of liquid flowing thereto will be; sheared oli in droplets of relatively uniform size.

Since the intermediate edge portions 24:] and 25d of. the nozzle ends are curved to extend generally longi-. tudinally of the direction of air flow past the nozzle, little or no shearing action occurs along these edge portions, but the liquid flowing thereto will mostly be blown by the air blast around toward the projecting downstream edges Zdc and 25c, where such liquids will be sheared or taken oi in droplets by the action of the air blast flowing across these transversely extending sharpened edge portions. It is obvious that since the longer downstream edges 24c and 25c of the head project out into unobstructed portions of the air stream, the most effective air flow will be across such projecting downstream edges, and therefore the normal flow of most of the liquid toward this downstream edge is a fortunate but inherent characteristic of the nozzle. This flow of a major portion of the liquid toward the downstream edges of the head, is not materially affected by the position of the nozzle with respect to the vertical, since the previously mentioned spreading action of jet impact plus the strong eddy currents within the head affect the flow of the liquid film toward the ends of the head much more than does gravity. Therefore, the liquid is sheared elf in a T618". tively uniform manner from all of the nozzles regardless of whether they are upright, on end, or inverted.

The fact that the spray particle size range remains relatively constant throughout a considerable range of volume output of liquid as set forth previously herein, is

extremely important in a nozzle of this character, since it allowsv the operator considerable latitude in his selection of spray density while retaining optimum particle size. This avoids the creation of an excessive amount of either excessively small droplets which tend to drift away or evaporate, or excessively large droplets which cause wasteful run-off.

While in the illustrated embodiment of the invention the nozzle head 23 is of circular cross sectional shape and the jet fitting 18 is separable therefrom, it will be obvious that the head can be of other cross sectional shapes, as mentioned previously herein, and that the body of the jet fitting can be formed, for example by well known die casting methods, as a part of the head. Also, while illustrated as being mounted in the air stream of ordinary types of Sprayers, the nozzle is capable of use in any air stream of suitable velocity, for example on an airplane for aerial spraying of crops or orchards.

It will be understood therefore that these and other changes and modifications in the details of the nozzle and its mounting arrangement may be made without departing from the spirit and scope of the invention as set forth in the appended claims,

Having thus, described the invention, what I claim new and desire to protect by Letters Patent is as foliows:

1. A shear nozzle comprising a conduit having an open end thereof sloped at an acute angle relative to its axis, means for directing a high velocity air stream past said open end, and means for supplying liquid, in suficient quantity to form a film, to the interior wall of said conduit for flow along the wall to the marginal edge portion of the open end of the conduit for shear takefl? y a d ai s r am- 2. A shear nozzle comprising a tubular head having an end thereof; sloped at a divergent angle relative to a transverse plane normal to the tubular axis of said head, means directing an air stream past said head and a liquid pp y pa ses-e penin hr ugh rific in the inicrior of said head to dis harge liquid interiorly of said head, for spreading in; the term; of a film over the interior thereof to said sloping end forshear take-offby said airstream.

iq i dis ibutin device c mpr si means for creating a high velocity air stream, a support having a liquid supply passage extending lengthwise therein and adapted to be connected at one end thereof to a liquid supply pipe, a short length of tubing: mounted on the other end of said support to he within the air stream with the tubing axis disposed at right angles to the direction of air flow past the tubing, the ends ot the tub ingbeing open, and disposed in planes diagonal to the tubing axis which m an. an le d v r e t in t direction of air flow past the tubing, and an opening from the supply passage into the interior of the tubing through an orifice positioned to direct the liquid discharged therethrough toward the interior of the tubing wall for spreading thereover in the formv of a film flowing to the diagonal tubing ends, there to, be sheared oil by the passing air stream.

4. A spray device comprising means for directing a high velocity air stream in a predetermined direction a portion of tubing having a sloping open end and mounted to extend transversely to the direction of flow of said air stream with the sloping open end of the tubing being directly exposed to. said air stream, and means for supplying a film of water to the edge of the tubing surrounding the sloping open end of said tubing to be sheared off" in droplets by the passing air stream.

References Cited in the file of this patent UNITED STATES PATENTS