US 3326473 A
Description (OCR text may contain errors)
F. W. WAHLIN SPRAY NOZZLE June 20, 1967 2 Sheets-Sheet l Filed Aug. 7, 1964 June 20, 1967 F. W. WAHLIN 3,326,473
SPRAY NOZZLE Filed Aug. 7, 1964 2 Sheets-Sheet E Il.. M
Y .i l 22B /0 o 6 ra /5 355V 3ZZB/^I Inverti/01a 26 3 5 efz www@ United States Patent O 3,326,473 SPRAY NOZZLE Fred W. Wahlin, St. Charles, Ill., assignor to Spraying Systems Co., a corporation of Illinois Filed Aug. 7, 1964, Ser. No. 388,138 6 Claims. (Cl. 239-468) This i-nvention relates to spray nozzles of the kind that Vproduce a hollow cone spray, and particularly the invention relates to the whirl chamber of such spray nozzles.
In spray nozzles of the aforesaid character the cir- Vcular spray orifice is formed as an axial outlet from one 'whirling movement of the water, the whirlpool effect results in an elongated cavity or air column extending centrally through the spray orice and downwardly within the swirl chamber and to or substantially to the opposite end or bottom wall of the whirl chamber.
It has long been understood that uniformity in the spray is dependent upon maintaining lthe whirling mass of water -in a centered and `axial relation to the discharge orifice, and it has been determined that when substantially the entire vertical length of the el-ongated central cavity or air column isV coaxial with the ori-tice, the spray produced is uniform. It was found however that because of the unbalanced introduction of the water tangentially of the Whirl chamber, there was a tendency of the water to whirl in an unbalanced relation wherein the lower end portion of the air cavity was shifted to one side away from the axis of the whirl chamber and the discharge orice. This of course produced an unbalanced spray, and hence many different proposals have been made for controlling and correcting the whirling mass in the whirl chamber.
An early expedient adapted for this purpose is shown in Wahlin Patent No. 2,247,897, patented July 1, 1941, in which a central depression or pocket was formed in the bottom wall of the chamber. This was found to be quite effective for centering the lower end ofthe air cavity and producing luniformity in the spray, but it was discovered that there was a distinct wearing action that took place at the center of the depression or pocket so that -a hole was often produced through the bottom wall of the whirl chamber. This excessive wear became so serious in many instances that removable bottom plugs, usually of a hard or wear resistant metal are provided for the whirl chambers of nozzles used where excessive wear is experienced.
Another expedient that was developed for centering the air pocket or cavity is disclosed in OBrien Patent No. 2,815,248, patented Dec. 3, 1957, and this arrangement involved forming the bottom wall as a ilat sloping surface. This Hat sloping surface was formed by an end milling tool inserted at an angle into the threaded upper end of the whirl chamber and while the resulting structure was found -to be satisfactory in those instances where the sloping at surface could be produced, it was found that the dimensions of the whirl chamber usually were such that a sufficiently large slope angle could not be obtained. To obtain a sufficiently great slope angle at the bottom of the whirl chamber resort has been had to the use of a collapsible metal insert that was put in place as a hollow cylinder in the bottom of .the whirl chamber and which was then crushed downwardly to provide the desired sloping bottom surface for the whirl chamber.
The several different structures that have been thus employed to center the whirling action of the water in 3,326,473 Patented June 20, 1967 rice such nozzles have been considered to be objectionable from the standpoint of excessive wear or cost, and also because they did not adapt themselves to redesign of the whirl chambers to meet different combinations of factors such as size, capacity, water pressure and the like. It is therefore the primary object of the present invention to enable control means to be provided in a simple and inexpensive manner in the whirl chambers of spray nozzles.
Other objects rela-ted to the foregoing are to provide control means of the aforesaid character in such a way as to minimize wear, simplify the production of the control means, and provide the control means in such a form .that its controlling action may be tested and modified in a simple manner to produce nozzle designs for specific combinations of controlling factors such as pressure size and the like.
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 inthe art without departing from the invention.
In the drawings:
FIG. l is a side elevational view of a hollow cone spray nozzle embodying the features of the invention;
FIG. 2 is a plan view of the nozzle;
Y FIG. 3 is an enlarged vertical sectional view taken along the line 3 3 of FIG. 2;
FIG. 4 is an enlarged fragmental plan view taken along lthe line 4--4 of FIG. 3; l
FIG. 5 is a vertical sectional view of the Whirl chamber taken along the line 5 5 of FIG. 7;
FIG. 6 is another vertical sectional view takenl along the line 5 5 of FIG. 7; and
FIG. 7 is a plan sectional view taken along the line 7 7 of FIG. 5.
For purposes of disclosure theinvention is herein illustrated as embodied in a hollow cone spray nozzle 20 that comprises a main ybody 21 within which a cylindrical Ywhirl chamber 22 is provided, and lwater or other liquid Vintroduced as a high velocity jet tangentially into the chamber 22, through a tangential inlet passage 23, whirls within the chamber 22 and is discharged from the chamber 22 through a cylindrical axial ori-tice 24 pro'- vided in a spray tip 25 that forms the top wall of the whirl chamber 22.
The main body 21 as herein shown has an integral nipple 26 extended from one side thereof, this nipple having external screw threads 26T so that in this instance a male connection is provided, and the tangential inlet passage 23 that extends through the nipple 26 at an angle C of from l0 to 15 degreesv to the vertical center plane of the nipple 26 as indicated in FIG. 7, so that the passage 23 enters the whirl chamber 22 in a tangential relation as shown in FIG. 4 and 7. As shown herein the passage 23 slopes downwardly at an angle E of about 4, but it noted that in smaller capacity nozzles this angle may be reduced to zero.
The whirl chamber 22 is formed as a downward bore from the top of the body 21, the lower end of the bore being milled at to provide a main bottom surface 22B for the whirl chamber 22 that is perpendicular to the axis of the bore that forms the chamber 22, and this surface 22B constitutes the main upper surface of a relatively thick bottom wall 22W for the whirl chamber 22. In its upper portion the bore that forms the whirl chamber 22 is internally screw threaded as at 22T to receive a threaded nipple 25N of the spray tip 25. The upper portion of the spray tip 25 is in the form of a ange 25F, which as shown is in the form of a hexagon nut so that the tip 25 may be tightened into place as shown in FIGS. 1 and 3.
The spray orice 24 has a tapered concentric enlargement 24L at its lower end so that entry of the whirling liquid into the spray orice 24 is facilitated, and in the present instance the upper or outer end of the oriiice 24 also has a concentric tapered portion 24U. The taper of` the surface 24U may be varied according to the spray angle desired. Thus when the whirling liquid moves outwardly through the orifice 24, it forms into a hollow cone spray S as indicated in FIG. 3. As the whirling liquid in the chamber 22 and'in the orifice 24 is formed into the spray S, an air column or cavity 30 forms which extends from the center of the spray S inwardly through the center of the orice 24 and downwardly through the Whirl chamber 22 and to the bottom of the whirl chamber 22, as shown in FIG. 3 of the drawing.
When the air column or cavity 30 is concentric at its upper end and throughout substantially its entire length with the axis of the orifice 24, the spray S is uniform, but as pointed out herein above, control means must be provided in association with the lower portion of the whirl chamber 22 in order to maintain such concentricity of 'the major portion of the cavity 30 with respect to the axis of the orifice.
Under and in accordance with the present invention, controlling means are provided for the whirling liquid by what amounts to an improvement and simplification of the fundamental structures shown in the aforesaid OBrien patent which discloses the Iprovision of a at sloping surface as the bottom of the whirl chamber. It was found that such at sloping surface could not be produced in many instances, and under the present invention it has been discovered that a rather complex but easily formed surface contour in the bottom wall will attain the desired controlling action while at the same time presenting a rather thick wear resisting bottom wall area in the general region where excessive wear would normally take place. l
The controlling contour that is herein illustrated in the upper surface 22B of the bottom wall 22W may be describedv generally as an annular groove 35 of arcuate cross section that varies gradually in width and depth from a narrow, shallow point 35N to a wide and deep point 35W, the points 35N and 35W being displaced 180 from each other, and the center line of the groove 35 being centered on the axis 22A of the Whirl chamber 22. The groove 35, at its widest point h-as a width slightly less than the radius of the whirl chamber 22, as will be evident in FIGS. 4, 6 and 7, so that the edges of vthe groove 35 at this point are spaced slightly from the side wall and from the center of the chamber 22, and this spacing increases gradually about the chamber 22 s0- that at the narrow point 35N of the groove 35, the spacing from the side wall and from the center of the chamber 22 is relatively great. These characteristics of form or contour therefore provide a continuous shelf like area of gradually varying width about the outer side of the groove 35, the shelf varea being the undisturbed portions of the bottom surface 22B, and providing a wide shelf area 122B opposite the narrow point 35N of the groove 35, and a narrow shelf area 222B opposite the wide point 35W of the groove 35. Further, a generally oval shelf area 322B is provided that is surrounded by the groove 35, the area 322B extending for a short distance beyond the axis 22A opposite the wide portion 35W of the groove 35, thus to include the axis 22A as will be evident in FIGS. 4, 6 and 7, and provide maximum thickness in the wall 22W where the wear tendency is the greatest.
The Wide 'and narrow points 35W and 35N of the whirling movement by an angle H from an angle H from an axial plane T of the chamber that passes through the point 23T where the inlet 23 meets the wall of the chamber 22 in a tangential relation. In the specific nozzle 20 herein shown, where the whirl chamber 22 has a diameter of 9A@ inch, the inlet 23 diameter may be varied from about .lll inch to about .343 inch according -to the desired discharge rate while the angle H that is used is approximately 52.
The relative depths of the groove 35 at the wide and narrow points 35W and 35N have an important bearing on the extent of the corrective or controlling action of the groove 35, and in FIG. 6, a way of determining or establishing this relationship has been shown. I'hus a line 38 extended through the deepest points or centers of the groove 35 at the narrow and Wide points 35N and 35W defines a slope angle S with the bottom surface 22B of the whirl'chamber 22, as shown in FIG. 6 of the drawings, and this angle S constitutes a measure of the severity of the correcting action caused by the groove 35. In the embodiment shown the slope angle S is about 17, but in general it should be noted that the angle S increases as the diameter of the inlet 23 increases. Thus, for inlet diameters of .111 inch and .343 inch, the slope S may be about 4 and 21, respectively.
In a nozzle 20, considered apart from the corrective action of the groove 35, the normal whirling action of the liquid tends to be unbalanced in such a way as to displace the lower end of the air column or cavity 30 to the left in the plane P as is overcome by the effective slope of the groove 35 from its narrow, shallow points 35N to its Wider, deeper point 35W, and the slope angle S, above described provides a measure of this corrective action. Thus, Where an inlet 23 of a relatively small diameter is used, a corrective slope of about 4 is used, and for larger diameter inlets, the angle may be increased gradually up to about 21 so as to attain an increased corrective action.
In designing a specific nozzle which will take into account the various dimensional and positional relationships in the structure as well as the dilferent combinations of liquid pressure, capacity and the like, the inal attainment of a properly balanced spray pattern usually involves the production and successive testing of a series 'of nozzles, and the corrective contour that is provided by the groove 35 under the present invention has been found to facilitate the design process to a marked and unexpected extent, as will be explained in connection with the description of the method of producing the nozzle 20. The body 10, with the whirl chamber 22, the threads 22T, the threaded nipple 26 and the passage 23 are formed in the usual way, and the groove 35 is formed by the use of an end milling tool 40, FIGS. 5 and 6, which has a rounded or semispherical lower milling surface 40R. The milling tool 40 has a diameter that is not more than one-half the diameter of the whirl chamber 22, and in the present instance the diameter of the tool 40 is exactly equal to one-half the chamber diameter and the surface 40R has the same diameter as the milling tool. In forming the groove 35, the axis 40A is disposed parallel to the axis 22A of the chamber 22 with the side edge of the tool 40 engaged with the side of the chamber 22 as shown in FIG. 6, and the tool 40 and the body 21 moved relative to each other about the axis 22A Y of the chamber 22 so that the axis 40A of the tool in effect traverses the line 140, FIG. 4, which constitutes the center line of the groove 35. The depth and width of the groove 35 is controlled during such relative movement of the tool 40 and body 21 by relatively moving the tool 40 and the body parallel to the axis 22A.
To accomplish the aforesaid relative movements to produce the groove 35, the body 21 may be clamped in a work fixture that is rotatable about the axis 22A of the body 21, and with the axis 40A of the tool 40 so related that When the work fixture is rotated about the axis 22A of the clamped body 21, the axis 40A of the tool 40 will in viewed in FIG. 7, and this tendency effect traverse the center line 140 of the groove 35 that is to be milled in the bottom wall 22W of the body 21. As such rotation of the body 21 takes place the work fixture and the body 21 may be moved toward and away from the tool 40 in accordance with the rotative position of the body 21. Thus cam means in the form of a cam plate, tilted at the desired slope angle S with respect to the axis 22A, and disposed with its cam surface perpendicular to the plane P, may act on the fixture to move the body 21 toward and away from the tool 40, thus to vary the width and depth of the groove 35 as required to produce the desired corrective action. The groove 35 may thus be formed at any selected slope angle S, and with the plane P in the desired location wth respect to the inlet passage 23.
In practice when a nozzle design is being perfected the necessary corrections may usually be made by changing the edective slope angle S, and because the groove 35 may be formed by a tool 40 with its axis 40A parallel to the axis 22A of the whirl chamber 22, the required changes in the slope angle S are independent of the depth-diameter relation of the whirl chamber 22. Hence the principles of the present invention iind wide application in the production of nozzles such as the nozzle 20.
In the operation of nozzles 20 embodying the invention, substantially the entire vertical length of the air cavity 30 is maintained concentric with the axis of the orifice 24 so that a uniform hollow cone spray is produced. It is found however that at its lower end the air cavity 30 is curved slightly in the plane P so as to be centered on au axis 30A, FIG. 6. The extreme lower end of the air cavity is thus located above the flat surface 322B where the full bottom wall thickness is presented to withstand wear, and yet, in the event that the bottom of the air cavity 30 is displaced to the right, FIG. 7, from the center of the whirl chamber, the cavity will be opposite a steeply sloping surface of the groove 35 so that the wearing action associated with the air cavity 30 will be minimized.
From the foregoing description it will be apparent that the present invention simplifies the provision of whirl control means in spray nozzles, simplifies the design and manufacture of such nozzles, reduces wear in the whirl chambers of such nozzles, and enables control means to be provided in such nozzles with the minimum of cost.
Thus while a preferred embodiment of the invention has been illustrated it is to be understood that changes and variations may be made by those skilled in the art without departing from the spirit and scope of the appended claims.
1. In a spray nozzle for producing a hollow conical spray and having a body with a circular whirl chamber therein defined by a circular side wall and a bottom wall, the body having an inlet passage opening tangentially into said circular chamber, and a nozzle tip closing the top of said chamber and having a spray discharge orifice therein disposed axially of the chamber, the improvement which comprises Whirl-correcting means formed as an annular groove of arcuate cross section in said lbottom wall and centered on said axis and varying uniformly in width and depth, the bottom of said groove lying in a plane disposed transversely to said axis and at an .angle with respect thereto.
2. The apparatus as set forth in claim 1 wherein the Widest and deepest place of said groove coincide, and the narrowest and shallowest place likewise coincide, and the Width of said groove varies uniformly 'between said points.
3. The apparatus as set forth in claim 1 wherein said annular groove is cut to depth which varies from a minimu-m to a maximum, such that the points of minimum and maximum depth lie on a line which forms an ac-ute angle with the axis of said orifice.
4. Apparatus as set forth in claim 3 wherein said inlet passage is located at a tangent to said circular chamber and disposed Iabove said annular groove.
5. Apparatus as set forth in claim 4 wherein said inlet is positioned so as to direct fluid toward that por-tion of said chamber wherein said annular ring has its place of maximum depth and width.
6. A spray nozzle of the type having a body portion dening a central whirl chamber, and having an inlet passage tangent to and opening into said whirl chamber, said whirl chamber being co-axial with a spray orice, -a whirlcorrecting groove formed in the flat bottom of said chamber, said groove being annular and having an outside diameter less than the diameter of said cham'ber so as to leave a portion of said bottom wall as a shelf about said groove, and defining a wear-resisting shelf surrounded by said groove, said groove being cut to a depth which varies gradually from a point of minimumrdepth disposed behind said inlet passage to a point of maximum depth, said points of minimum and :maximum depth lying on a straight line in a plane disposed transversely to the axis of said whirl chamber and sloping away from said inlet passage.
References Cited UNITED STATES PATENTS 1,938,000 12/ 1933 Wahlin 239-468 2,815,248 12/ 1957 OBrien 239-468 3,107,859 10/ 1963 Gilson 239-468 3,182,916 5/ 1965 Schulz 239-468 3,196,748 7/'1965 Apthorp 90-11.42 3,209,652 10/ 1965 Burgsmueller 9C- MAZ FOREIGN PATENTS 212,636 2/ 1958 Australia. 1,079,441 5/ 1954 France.
M. HENSON WOOD, IR., Primary Examiner,
R. S. STROBEL, Assistant Examiner,