US3072346A - Spray nozzle - Google Patents

Description

SPRAY NOZZLE Filed Sept. 29, 1961 Ci [I Z11 hverza ars SPIPA r/I/vau' Unite 3,072,346 SPRAY NOZZLE Fred W. Wahlin, St. Charles, and Edward J. OBrien, Glen Ellyn, Ill., assignors to Spraying Systems Co., a corporation of Illinois Filed Sept. 29, 1961, Ser. No. 141,883 6 Claims. (Cl. 239-437 are, however, situations where a wider angle in such a square patterned spray is desirable, and to enable this to be accomplished is the primary object of this invention.

A further important object of this invention is to provide means for controlling the spray pattern of a nozzle for producing a wide angle solid cone spray with a square spray pattern, and a related object is to enable this to be accomplished in a Wide angle spray by means that are simple in character.

Other and further objects of the present invention will be apparent from the following description and claims, and are illustrated in the accompanying drawings, which, by way of illustration, show a preferred embodiment of the present invention and the principles thereof, and what is now considered to be the best mode in which to apply these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the invention.

In the drawings:

FIG. 1 is a front end elevational view of a spray nozzle embodying the features of the invention;

FIG. 2 is a side elevational view of the nozzle;

FIG. 3 is a longitudinal cross sectional view of the nozzle taken substantially along the line 3-3 of FIG. 1;

FIG. 4 is a schematic view illustrating the square spray pattern and its relation to the structural parts of the nozzle; and

FIG. 5 is a schematic view taken in the longitudinal central plane of the nozzle as indicated by the line 5-5 of FIG. 1.

For purposes of disclosure the invention is herein illustrated as embodied in a spray nozzle whereby a liquid may be discharged in a full cone Wide angle liquid spray for deposit in a square spray pattern P, as shown diagrammatically in FIG. 4. Thenozzle 10, as herein shown, comprises an elongated hollowcylindrical body 11 which, to provide a male connection to a source of liquid under pressure, is externallythreaded at its rear end and at UT, and, interio-rly, thebody 11 provides a forwardly extending cylindrical internal passage orchamber 12 which at its forward end is tapered or curved radially inwardly as at 14 to meet the rear end of an axial,cylindrical discharge orifice 15.

Thedischarge orifice 15 has a substantial axial length, and it then merges at its outer end with an outwardly flared discharge end ormouth 16 which is formed as a surface of revolution about theaxis 17, FIG. 5, of thedischarge orifice 15. FIG. 5 is a schematic view, of course taken substantially along the line 5-5 of FIG. 1, and as indicated in FIG. 5, the annular surface of revo- States atent lution that provides the flaredmouth 16 is formed, in cross section, on a radius R centered radially outwardly of the flaredmouth 16. The radius R may be varied with relation to the diameter D of theorifice 15, but usually the radius R of the flaredmouth 16 is chosen at a value about equal to or less the diameter D of theorifice 15, this selection being governed by considerations that will be described in further detail hereinafter.

The liquid, such as water, that is to be sprayed, has a whirling and turbulent motion imparted thereto within thechamber 12 of thenozzle 10, as by a vane orswirl member 18 that is held in the rear end of thechamber 12. Theswirl member 18 may be of the form and construction illustrated and described in Wahlin Patent No. 2,305,210, patented December 15, 1942.

The relationship between the orifice diameter D and the diameter V of thevane unit 18 is important in assuring the production of a full cone spray with substantially uniform distribution of liquid. Thus, if the orifice diameter D is too large in relation to the diameter V of the vane unit, the full cone pattern is lost, and it is found that for producing to spray, the best results are obtained Where the orifice diameter is from 0.4 to 0.5 of the vane diameter V. The orifice diameter D, however, must be sufficiently large to enable the swirling liquid to follow the side surfaces of the orifice.

The advancing liquid, swirling about theaxis 17, moves through theorifice 15 and into the flaredmouth 16, and as it advances through the flaredmouth 16, the transverse or cross sectional area of the column of whirling liquid increases as controlled by the form or flare of themouth 16. When the liquid leaves thefiared mouth 16 of the nozzle, such liquid forms into a solid cone spray that has wide angle characteristics resulting in a large measure from the provision of the flaredmouth 16 on theorifice 15 of the nozzle. It is to be noted, however, that the spray angle also varies to some extent with spraying pressure.

Under and in accordance with the present invention the swirling liquid column of liquid passing forwardly through the flaredmouth 16 is governed and controlled in a unique manner so that it is deposited in the desired square spray pattern P, and this control of the spray is attained through the provision of structural characteristics in thenozzle 10 that are simple and economical in character. Basically, the structural form and relationship required to attain the desired control of the spray pattern P is provided by milling away the outer sides of thebody 11 about the forward end of the flaredmouth 16 to form outer side faces 20 intersecting and variantly modifying effective length of the flaredsurface 16; and thesefaces 20 are parallel to theaxis 17, and in end elevation, as shown in FIG. 1, are arranged in the form of a square centered on theaxis 17 of theorifice 15 and having a side dimension A.

It is recognized that the provision of side surfaces, generally like the side faces 20, which intersect and vary the efiective length of the flaredmouth 16 of the nozzle may be utilized to attain spray patterns other than the square spray pattern P, but so far as We have been able to determine, the square spray pattern P that is attained by the structure herein disclosed is the most important pattern in a commercial sense.

The dimension A, or in other words, the spacing of the side faces 20 from theaxis 17 is important in attaining the desired square spray pattern, as will presently appear, and while the dimension A may be determined generally on a mathematical basis, no mathematical way has been found which will in every instance determine this spacing with absolute accuracy. However, it has been found that after mathematically determining the dimension A, the milling operations involved in forming the side faces 2%) may be performed in a succession of steps alternated with tests of the nozzle to arrive at the precise dimension A of the square required in a nozzle that is being designed, and by this procedure the resulting nozzle takes into account all of the variable factors and relationships present, such as the orifice radius, the flare radius, the liquid pressure, the character of the liquid, and the proposed normal spacing of the nozzle from the surface to be sprayed.

As a basis for explanation of the functioning of the present structure in attaining the square P, and as a basis for an explanation of the mathematical way of preliminarily calculating certain dimensions of the nozzle, it should be observed that eachside face 2% intersects theflared mouth 16 in such a way that theside face 20 has downwardly concave upper orforward edge 21, as shown in FIGS. 2 and 3. Thisedge 21 thus defines the forward or outer extent of the flaredsurface 16 which confines and controls the swirling liquid as it is being formed into a Wide angle spray. The advancing column of whirling liquid continues to increase in cross section under control of the flaredsurface 16, but when the liquid advances past theedge 21, the whirling motion as to such liquid tnat has passed theedge 21 stops and such liquid progresses freely forwardly and outwardly at or within a spray angle determined by the angular relation of the flaredsurface 16 at the point where the liquid has passed anedge 21.

Thus, by reference to the schematic illustration of FIG. 5, the intersection of theside face 20 with theflared surface 16 in the plane -5 of FlG. l is indicated at 21C, While the corresponding intersection of theflare 16 and the face 29 in the plane 33 of HG. l is identified as 21E. Thepoints 21C and 21B are thus located at the end and the center respectively of one of thearcuate edges 21, and between thepoints 21C and 21E there is a gradual variation in the extent or effective length of theflared surface 16 between theedge 21 and the smallest diameter portion 168 of theflared surface 16, FIG. 5.

For illustrative purposes it is noted that, at thepoint 21E, a tangent to theflared surface 16 extends along the line E, while a similar tangent at the point 211C extends along the line C, and because of the continued outward flare of thesurface 16 between thepoints 21E and 2lC, theangle 23E between the line B and thespray axis 17 is substantially greater than the angle 23C between the line C and thespray axis 17. The advancing liquid which has been expanded within the flaredmouth 16 to form the wide angle spray, thus progresses forwardly and laterally after it passes theedge 21 with its outer boundary located substantially along the tangent, such as the tangent C or the tangent E at the point Where such liquid passessuch edge 21. The liquid passing thepoint 21C at a larger angle to theaxis 17, reaches the work surface W, FIG. 5, along the line C, FIGS. 4 and 5, while the liquid passing thepoint 21E reaches the work surface W being sprayed along the line E, FIGS. 4 and 5, and intermediate thepoints 21C and 215, the extreme edge of the pattern P is varied as to its distance from the center line 17' for the reasons above set forth so as to produce the desired square spray pattern P.

As hereinabove pointed out, the dimension A of the square formed by thefaces 20 is a determining factor in attaining a truly square pattern P, and in the design of a spray nozzle the approximate dimension A may first be calculated and then checked graphically, as will be described, after which it is considered to be best practice to make a trial nozzle, conforming to the results of such calculations, and to test the same so as to determine its performance under the proposed combination of orifice diameter D, flare radius R, spraying pressure, liquid characteristics and spray distance x. The general mathematical and graphical procedure, and the other design considerations, will be outlined hereinafter, but it should be pointed out that in building a nozzle for such a test, the dimension A of thesquared nozzle surfaces 20 is preferably made somewhat larger than is theoretically and mathematically indicated, and this dimension A is then reduced, as required, by step by step milling of thefaces 20, with intermediate testing of the spray nozzle to determine its actual spray pattern. As to this procedure, it may be noted that when the side faces Ztl are spaced relatively far from theaxis 17 it is found that a pattern with outwardly rounded or convex sides is produced, and as the dimension A is made progressively smaller, the convexity of the sides S of the pattern becomes less and less until the desired straight sided square pattern is produced.

In designing a nozzle according to the present invention, orifice diameter D must first be selected. This diameter must be sufficiently large to insure that the whirling liquid will follow the form of the orifice, and experience has shown that about 0.14 inch is about the I smallest orifice diameter with which this result may be accomplished. Secondly, the diameter V of the vane orwhirl unit 1% must be selected, and this may be such that the orifice diameter D equals about .4 to .5 of the vane diameter V.

As the next step, the radius R is selected, and as a general consideration it must be kept in mind that this radius must be suificiently large in an absolute sense to enable the whirling liquid to follow and in effect expand in contact with the flaredmouth 16 of thenozzle 10. In those nozzles where theorifice 15 is of small diameter, the radius R must be relatively large as compared with the orifice diameter, but as the orifice diameter is increased, it is not necessary to correspondingly increase the radius R. In fact, withorifices 15 that are from 0.14 to 0.17 inch in diameter, it has been found that a radius R substantially equalling the diameter D is desirable, while with an orifice of about inch or larger, the radius R may be substantially smaller in relation to the orifice diameter D. A radius of about one-half the diameter D has been found to be highly satisfactory with orifice diameters D of from about inch to about 1% inch, although it may be pointed out that larger ratios of radius R to diameter D might be used except for the fact that this would unduly increase the overall diameter and bulk of thenozzle 10.

Having made the initial selection of the orifice diameter D, the vane diameter V, the radius R, and the appoximate size or dimension Y, FIG. 4, of the desired square pattern P being known, the dimension A of the square to be formed by theside faces 20 may be preliminarily determined along the following lines.

The approximate spray angle must also be selected, and using this angle and the selected spray pattern dimension Y, the spray distance x may be computed. Theangle 23E, of course, is equal to one half of the spray angle that has been selected, and assuming that thisselected angle 23E is 57, the data available enables the angle 23C to be computed as approximately 65, and this data may then be used to plot and preliminarily check the progress of the design work. Such plotting may he done along the lines of FIG. 5 Where theaxis 17, the orifice D and theflared mouth 16 have been laid out to scale, along with a work surface W. Lines E and C are then laid out as tangents to thesurface 16 at angles 1235 and 123C that correspond with the determined angles 235 and 23C, and these tangents intersect the work surface W at E-l and C-1 respectively.

In order to produce the desired square spray pattern P, the points of intersection Ell and C4 should be spaced from theaxis 17 in a substantially predetermined relation, so that the distance from theaxis 17 to the point C4; is substantially 1.414 times the distance from theaxis 17 to the point E-l. As shown in FIG. 5, however, this relationship is not attained, and with structure formed as shown in FIG. 5, the spray pattern would have outwardly convex sides.

. Upon the basis of the foregoing considerations asmaller angle 23E may be. selected and theangle 230 may be computed, followed by plotting of the tangents C and E for the newly selected angle. For the relationship of orifice diameter D and flare radius R, anangle 23E of 45 might well be a logical second selection for design purposes, and in fact, upon computation and plotting along the above lines would be shown to provide a nozzle structure that closely approaches a square pattern.

Having determined anangle 23E which will closely ap proach a satisfactory square spray pattern, the approximate dimension A may be measured on the graphic representation like FIG. 5, or may be calculated. Thus, in FIG. 5, theangle 123E has been indicated which is equal to theangle 23E, and the dimension A that should theoretically be used in forming thefaces 20 may be calculated from the formula:

Upon the basis of such calculations, the desired nozzle may be made with the dimension A somewhat larger than the calculated value, and then upon test under the proposed conditions of use, the dimension A may be progressively reduced as described hereinabove until the resulting spray pattern P is of square form.

Anozzle 10, that has been designed according to the foregoing procedure may be readily produced according to standard machine shop practices and the resulting nozzles will uniformly produce the wide angle square pattern for which they have been designed.

Proceeding according to the foregoing; a range of nozzle designs has been developed under this invention as shown by the following Table I which sets forth the critical dimensions of various sizes of such nozzles; and the table further includes a mathematical factor K that has been computed as to each nozzle and which will be explained hereinafter.

Table 1 Dimension Radius of Commercial Nozzle A of Square Orifice Flared Factor Size Designation Formed By Dia. D Mouth 16 K Faces Based on the dimension and relationships of the several nozzles, as above set forth in Table I, it has been determined that there is a factor K that may be derived from these dimensions and'which, for nozzles that provide the desired spray pattern, falls within a predetermined range. This factor K is determined from the formula:

As applied tothe specific nozzles included in Table I, the factor K as above computed has been set forth in the last column in Table I, and it will be noted that this factor K varies within a range of about .70 to about 1.3. Thus, spray nozzles embodying this invention and producing a square spray pattern may vary as to their factor Thus, while a preferred embodiment of the invention has been illustrated and described herein, variations and changes may be made therein by those skilled in the art without departing from the spirit and cope of the invention as defined by the appended claims.

We claim:

1. In a spray nozzle for producing a wide angle solid cone spray with a square pattern, a hollow body having an elongated cylindrical chamber with an axial cylindrical discharge orifice of a reduced size at a forward end thereof, a swirl unit within the chamber for imparting swirling movement to liquid moving in said chamber toward the discharge orifice, said orifice at its outer end being formed with a flared surface defining a mouth for the orifice, and said body being formed with four side faces parallel to the axis of the orifice and in the form of a square centered on the axis of the orifice and with the faces parallel to the axis of the orifice, said faces being arranged to intersect said flared surface to define lines of intersection of the side face with said flared surface that provide concave forward edges for said side faces.

2. A spray nozzle according toclaim 1 wherein said flared surface being formed as the surface of revolution of an arcuate surface that meets said cylindrical orifice in a tangential relation.

3. In a spray nozzle for producing a wide angle solid cone spray with a square pattern, a hollow body having an elongated cylindrical chamber with an axial cylindrical discharge orifice of a reduced size at a forward end thereof, a swirl unit Within the chamber for imparting swirling movement to liquid moving in said chamber toward the discharge orifice, said orifice at its forward end having an outwardly flared surface formed as a surface of revolution about the axis of said orifice and defining a mouth for the orifice, and said body being formed with four side faces parallel to the axis of the orifice and in the form of a square centered on the axis of the orifice and with the faces parallel to the axis of the orifice, and with said faces being arranged to intersect said flared surface.

4. In a spray nozzle, an elongated body having front and rear ends with an axial chamber therein having an inlet end opening through said rear end of the body and having its forward portion reduced to define an axial discharge orifice of cylindrical form through said forward end of the body, the forward portion of the discharge orifice having an outwardly flared surface in a coaxial relation with respect to said cylindrical discharge orifice, means in said chamber for imparting swirling movement to liquid about the axis of the chamber as such liquid moves through the chamber toward said orifice, said body adjacent the forward end thereof having at least one planar side surface substantially parallel to the axis of said orifice and intersecting said flared surface as a chord.

5. In a spray nozzle, an elongated body havi g front and rear ends with an axial chamber therein having inlet end opening through said rear end of the body and having its forward portion reduced to define an axial discharge orifice of cylindrical form through said forward end of the body, the forward portion of the discharge orifice having an outwardly flared surface merging smoothly with said cylindrical discharge orifice as a coaxial forward continuation of such orifice, means in said chamber for imparting swirling movement to liquid about the axis of the chamber as such liquid moves through the chamber toward said orifice, and said body adjacent the forward end thereof having at least one planar side surface intersecting said flared surface as a chord at varying distances from the axis of the said orifice.

6. In a spray nozzle for producing a wide angle solid cone spray with a square pattern, a hollow body having an elongated cylindrical chamber with an axial cylindrical discharge orifice of a reduced size at a forward end thereof, a swirl unit Within the chamber for imparting swirling movement to liquid moving in said chamber toward the discharge orifice, said orifice at its outer end being formed with a flared surface forming a mouth for the orifice, said flared surface being formed as a surface of revolution of an arc of predetermined radius, and said body being formed with four side faces parallel to the axis of the orifice and in the form of a square centered on the axis of the orifice and with the faces parallel to the axis of the orifice with said faces being arranged to intersect said flared surface, said nozzle having a factor K falling substantially within a range of about .7 to about 1.3, where the factor K is determined by the formula 8 and where A is the side dimension of said square, D is the diameter of said discharge orifice, and R isthe radius of said are.

References Cited in the file of this patent UNITED STATES PATENTS 1,463,666 Buckner July 31, 1923 1,668,271 Fisk May 1, 1928 1,780,233 Jenkins Nov. 4, 1930 2,305,210 Wahlin Dec. 15, 1942 2,924,394 Clark Feb. 9, 1960 2,999,648 Wahlin et a1. Sept. 12, 1961

Claims (1)

1. IN A SPRAY NOZZLE FOR PRODUCING A WIDE ANGLE SOLID CONE SPRAY WITH A SQUARE PATTERN, A HOLLOW BODY HAVING AN ELONGATED CYLINDRICAL CHAMBER WITH AN AXIAL CYLINDRICAL DISCHARGE ORIFICE OF A REDUCED SIZE AT A FORWARD END THEREOF, A SWIRL UNIT WITHIN THE CHAMBER FOR IMPARTING SWIRLING MOVEMENT TO LIQUID MOVING IN SAID CHAMBER TOWARD THE DISCHARGE ORIFICE, SAID ORIFICE AT ITS OUTER END BEING FORMED WITH A FLARED SURFACE DEFINING A MOUTH FOR THE ORIFICE, AND SAID BODY BEING FORMED WITH FOUR SIDE FACES PARALLEL TO THE AXIS OF THE ORIFICE AND IN THE FORM OF A SQUARE CENTERED ON THE AXIS OF THE ORIFICE AND WITH THE FACES PARALLEL TO THE AXIS OF THE ORIFICE, SAID FACES BEING ARRANGED TO INTERSECT SAID FLARED SURFACE TO DEFINE LINES OF INTERSECTION OF THE SIDE FACE WITH SAID FLARED SURFACE THAT PROVIDE CONCAVE FORWARD EDGES FOR SAID SIDE FACES.

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