Construction for reducing vortex swirl in rotary water sprinklers

[57] ABSTRACT

A rotary impact driven sprinkler of the type having a range nozzle for long distance water throw and a spreader nozzle for shorter distance throw and which includes an elbow having a converging passageway therethrough for reducing vortex swirl, and a bleed opening in the passageway for further reducing the amount of swirling water delivered to the range nozzle by bleeding the swirling water from the main flow and directing that water to supply the spreader nozzle.

Claims, 7 Drawing Figures

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U.S. Patent Dec. 9,1975

3,924,809

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3,924,809

CONSTRUCTION FOR REDUCING VORTEX SWIRL IN ROTARY WATER SPRINKLERS

BACKGROUND OF THE INVENTION

This invention relates to rotary water sprinklers for use in irrigation and more particularly to a new and improved rotary sprinkler of the type having a primary nozzle for relatively long distance water throw and a secondary nozzle for relatively short distance water throw.

There are numerous rotary sprinklers presently on the market which include a primary nozzle, often referred to as a “range nozzle,” for providing the primary source of irrigating water, and a secondary nozzle, typically called a “spreader nozzle,” which ejects a smaller water stream. Exemplary of these types of sprinklers are those manufactured and sold by Rain Bird Sprinkler Manufacturing Corp, of Glendora, Calif, under its designations 85E-TNT/95E-TNT (part circle sprinklers), and full circle sprinklers 80C and 80E Series as shown on pages 64 and 80, respectively, of the Rain Bird 1974 Irrigation Equipment Catalogue.

Such sprinklers are typically used in situations where relatively large areas are to be irrigated, the range nozzle functioning to eject its stream over a relatively great distance with its main fallout occuring well away from the sprinkler, and the spreader nozzle functioning to eject its stream over a shorter distance to produce relatively rapid fallout and fill in the area of low fallout created by the range nozzle. The range nozzle typically is disposed to traject its stream in a direction upwardly and laterally away from the sprinkler so that the water from the supply pipe which is usually vertically disposed must travel through a curved, generally elbow shaped path to the range nozzle.

It has been found that as the water travels through the elbow, vortex swirl is introduced into the water flowing to the range nozzle so that the water ejected from the range nozzle includes water particles which are traveling with a spiral motion in their direction of travel. This results in a substantial reduction in the distance of travel of the water stream from the range nozzle before fallout and a reduction in the area which can be effectively irrigated by the sprinkler.

To over come this problem, various attempts have been made at reducing the vortex swirl of the water ejected from the range nozzle. One of the most successful solutions has been to form anti swirl vanes inside the sprinkler downstream from the elbow and upstream from the range nozzle and which attempt to align the water particles into a straight line flow condition prepatory to being ejected from the range nozzle.

While the provision of straightening vanes has increased the effective distance of water throw from the range nozzle, such vanes have also introduced several additional problems and have not fully solved the underlying problem. For example, the provision of vanes adds additional material and labor costs to the construction of such sprinklers, and the vanes tend to provide a flow restriction which may result in clogging of the sprinkler after prolonged use and the build up of dirt and particulate matter around the vanes.

Thus, it is apparent that there exists a need for a new and improved sprinkler of the type referred to above which is simple and inexpensive in construction, and which will increase the effective distance of water throw from the range nozzle yet be trouble free in use.

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SUMMARY OF THE INVENTION

This invention provides a sprinkler construction which substantially reduces the amount of vortex swirl of the water flowing through an elbow to a range nozzle and which significantly increases the effective area irrigated over similar types of prior art sprinklers. Moreover, the sprinkler construction of the present invention is relatively inexpensive to manufacture, is trouble free and reliable in use, and attains its improved result without requiring anti swirl vanes or the like.

More specifically, the flow passage through the elbow leading to the range nozzle is formed as a uniformly converging passageway of circular cross-section and which accelerates the flow in the lonitudinal direction of travel to reduce the amount of energy that is available for producing vortex swirl. The passageway also includes a lateral bleed opening which is positioned to effectively bleed swirling water particles from the flow to the range nozzle and to channel the swirling water to a spreader nozzle.

The passageway through the elbow is defined by a rear wall having an outer radius of curvature and a forward wall having an inner radius of curvature, and the bleed opening is formed as a slot through the forward wall. The spreader nozzle is attached to the end of a tubular projection extending laterally from the elbow below the range nozzle and in general alignment therewith, and has an internal conduit communicating with the bleed opening. With this construction, a substantial portion of the water swirl that is produced during flow through the elbow is channeled out of the main flow and directed to the spreader nozzle.

Although the formation of vortex swirl may not be entirely eliminated by the converging passageway through the elbow, it will be appreciated that not only is the amount of swirl reduced appreciably, but the bleed opening cooperates to channel off much of the swirl that is developed during travel through the elbow thereby to increase the distance of water throw from the range nozzle. Further, it should be appreciated that the construction of the sprinkler is relatively simple, easy to manufacture and free of clogging problems of prior art sprinklers.

Many other features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the drawings which disclose, by way of example, the principles of the invention.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view with portions shown in perspective, of a rotary, impact driven sprinkler embodying the principles of the invention and which includes a range nozzle and a spreader nozzle;

FIG. 2 is a fragmentary perspective view taken substantially in the direction of line 2—2 of FIG. 1;

FIG. 3 is a sectional view taken substantially along the line 3—3 of FIG. 1;

FIG. 4 is another sectional view and taken substantially along line 4—4 of FIG. 1;

FIG. 5 is a further sectional view and taken substantially along line 5—5 of FIG. 1;

FIG. 6 is a fragmentary front perspective view of the sprinkler of FIG. 1; and

FIG. 7 is a fragmentary top plan view of the sprinkler of FIG. 1.

3,924,809

DETAILED DESCRIPTION

As shown in the exemplary drawings, the present invention is embodied in a new and improved rotary water sprinkler 10 of the type having a primary or range nozzle 12 for ejecting a stream of water over a relatively long distance, and a secondary or spreader nozzle 14 for ejecting a water stream over a shorter distance. In this instance, the sprinkler 10 is coupled to a generally vertical water supply pipe 16 which provides pressurized water to the sprinkler, and is mounted for full circle rotation in one direction about the pipe. In this connection, it should be appreciated that although the sprinkler 10 is illustrated as a full circle type sprinkler, the sprinkler can be adapted for part circle operation by providing a suitable reversing mechanism of conventional design.

Referring primarily to FIGS. 1 and 6, the sprinkler 10 includes a body 18, herein formed from a metal casting, having a lower portion 20 defining an internal, generally vertical water inlet passage 22 which communicates with the supply pipe 16 through a conventional rotary coupling 24 comprising a tubular spindle 26 journaled within a sleeve 28 threaded to the pipe, and a bearing spring 30 compressed between the body and a pair of bearing rings 32 disposed around the spindle above the sleeve. A curved central portion or elbow 34 of the body 18 projects upwardly and laterally from the lower portion 20 and terminates in an upper tubular portion 36 to which the range nozzle 12 is coupled. The range nozzle 12 communicates with the vertical inlet passage 26 through a curved central flow passage 38, within the elbow 34 and which if cut longitudinally along the centerline as seen in FIG. 1 is defined by a rear wall 35 having an outer radius of curvature and a forward wall 37 having an inner radius of curvature. The elbow 34, is formed so that water ejected from the range nozzle 12 travels in an upwardly and laterally directed path from the sprinkler 10.

While the range nozzle 12 can take various forms, herein the nozzle comprises a tube of circular crosssection having an elongated cylindrical section 40 which projects outwardly from the body 18 and converges uniformly to an outlet section 42. Inwardly, the cylindrical section 40 terminates in an enlarged peripheral flange 44 which is clamped to the upper end portion 36 of the body 18 by an oppositely flanged collar 46 threaded to the body. An O-ring seal 48 disposed between the outer end of the body 18 and the inner surface of the flange 44 forms a liquid seal between the range nozzle 12 and the body to prevent water leakage.

For reasons that will become more apparent hereinafter, the spreader nozzle 14 is coupled to the outer end of a tubular projection 50 which extends outwardly from the elbow 34 and located below the range nozzle 12 in general alignment therewith. Depending below the tubular projection 50 is an open sided, generally Ushaped frame or cage 52 comprising a front post 54 projecting downwardly from the tubular projection, a base plate 56 projecting rearwardly from the lower end of the post, and a rear strut 58 attached to the rear end of the base and to the lower portion 20 of the body.

For driving the sprinkler 10 in a rotary direction about the supply pipe 16, an impact drive assembly 60 of generally conventional design is supported by the cage 52 of the body 18 below the range nozzle 12. Herein, the impact drive assembly 60 is operated by the water stream ejected from the spreader nozzle 14 and produces incrimental rotation of the sprinkler 10 in a clockwise direction about the supply pipe 16 as viewed in FIGS. 1 and 7.

As illustrated in FIGS. 1 and 6, the impact drive assembly 60 comprises an impact arm 62 mounted adjacent one end, the left end in FIG. 1, for rotation on a journal pin 64 supported between the tubular projection 50 and the base 56 of the cage 52, and carries a drive spoon or vane 66 at its opposite end which is designed to be aligned with the spreader nozzle 14 so that the water stream from the spreader nozzle can impinge on the vane. A torsion spring 68 connected at its lower end to the base 56 and at its upper end to the impact arm 62 normally biases the vane 66 into the path of the water stream from the spreader nozzle 14 and operates in a conventional manner to pull the vane back into the stream from the spreader nozzle when the vane has been deflected out of the stream by the stream pressure, thereby causing the impact arm to strike the foreward post 54 of the cage 52 and impart an incremental rotation to the sprinkler 10.

In accordance with the present invention, the central flow passage 38 and the tubular projection 50 cooperate to effectively reduce swirling motion of water flowing through the elbow 34 to the range nozzle 12 and significantly increase the distance of throw of the water stream ejected by the range nozzle to enlarge the size of the area irrigated by the sprinkler 10. Further, the sprinkler 10 of this invention is relatively inexpensive to manufacture, is trouble free and reliable in use, and does not require any vanes or the like in the water passages to obtain its improved result.

Toward the foregoing ends, the central flow passage 38 is formed as a uniformly and upwardly converging passageway of circular cross-section and which includes a lateral bleed opening 70 positioned in such a manner to effectively bleed swirling water particles from the central flow passage and supply pressurized water through the tubular projection 50 to the spreader nozzle 14. It has been found that by forming the central passage 38 as a uniformly converging passageway, the water flowing through the central passage is accelerated in the longitudinal direction of flow, and a substantial reduction in the amount of vortex swirl produced in the water flowing through the elbow 34 is achieved. Moreover, by appropriately locating the bleed opening 70 to the spreader nozzle 14, a substantial portion of the water swirl that is developed during flow through the elbow 34 can be channeled out of the main flow and directed to the spreader nozzle.

Referring primarily to FIG. 1, as water passes through the elbow 34, vortex swirl is introduced due to the longer distance water particles near the rear wall 35 must travel as compared with water particles traveling near the forward wall 37. The vortex swirl induced into the flow tends to take the form of eddy currents traveling from the centerline of the elbow 34 upwardly toward the rear wall 35, then laterally around the periphery and downwardly toward the forward wall 37, and then back in an upwardly direction toward the centerline as FIG. 1 is viewed.

By accelerating the flow in the direction of the centerline of the elbow 34, a substantial reduction in vortex swirl is achieved due to an increase in the amount of energy required to accelerate the flow in the direction of the centerline and a consequential reduction in the amount of energy available for vortex flow. Thus, the formation of vortex swirl is inhibited substantially by

3,924,809 the converging nature of the central flow passage 38.

Additionally, the bleed opening 70 is formed in the forward wall 37 so that a substantial portion of the vortex swirl that is produced during travel through the elbow 34 will be directed to the spreader nozzle 14 rather than rejoining the main flow to the range nozzle 12. As best seen in FIGS. 1 and 2, the bleed opening 70 is formed as a slot through the forward wall 37 and which has parallel sides 72 elongated in the longitudinal direction and connected by rounded ends 74.

Water bled from the main flow in the central passage 38 through the bleed opening 70 is directed to the spreader nozzle 14 through a conduit 76 defined within the tubular projection 50. As shown in FIGS. 3 through 5, the conduit 76 has a substantially constant cross-sectional area although the shape continuously and uniformly changes from an elliptical configuration (FIG. 2) adjacent the bleed opening 70 to a circular configuration (FIG. 5) adjacent the outer end of the tubular projection to which the spreader nozzle 14 is attached, herein by a threaded connection 78.

Referring to FIGS. 6 and 7, it will be noted that the tubular projection 70 is obliquely disposed to project outwardly from the elbow 34 at a small lateral angle with respect to the range nozzle 12 so that the water stream from the spreader nozzle 14 will be ejected somewhat laterally and not be directly below that ejected by the range nozzle. It has been found that if the stream from the spreader nozzle 14 were directed below that of the range nozzle 12, water from the spreader nozzle would tend to be sucked into the range nozzle stream and disrupt the fallout pattern. By laterally offsetting the direction of the stream from the spreader nozzle 14, the water particles in the stream from the spreader nozzle will not be sucked into the stream from the range nozzle 12.

In comparative tests between a sprinkler constructed in accordance with the present invention and a conventional sprinkler of the same size and general type and which included anti swirl internal vanes, it was found that about a 15 percent increase in the effective distance of water throw under substantially the same conditions was achieved with the sprinkler employing the principles of the present invention. Thus, it should be apparent that the present invention substantially enhances the effective watering area of a sprinkler having a range nozzle and a spreader nozzle, even one employing anti swirl vanes upstream from the range nozzle.

While a particular form of the invention has been illustrated and discribed, it should be apparent that various modifications and variations therein can be made without departing from the spirit and scope of the invention.