An object of the invention is to reach a substantial uniformity of water distribution along the trajectory of the sprinkler jet and, in the case of rotating sprinklers, in the different angular positions of the watered circle. Another object is to reduce to a minimum the excess of water in proximity to the sprinkler compared to watered zones farther away from it.

These and further objects and advantages will result from the following text.

An improved nozzle, usable with both static and rotating sprinklers, is inclined with respect to the horizon and has an initial angulation ; it is characterized in that the cross section of the water flow opening is rectangular ; in the initial zone it is square with a gradual lowering of the inferior surface and a gradual increase of the vertical sides of the cross section.

Basically the inferior surface is lowered to reduce its angulation by about 6° to 8°, compared to the initial angulation.

The initial angulation is between 7'and 250, and in particular around 23°.

In a static sprinkler (i. e. one which has no deflector arm that moves it) that has an initial angulation of 23°, the inferior surface can be lowered until it reaches about 15°, with respect to the horizon, in the last 4-6 mm from the point of exit. In the last millimeters the inclination can be even further lowered to reach 9°.

In a rotating sprinkler (i. e. one that has a deflector arm that is hit by the outcoming flow from the nozzle) the inferior surface is lowered, from its initial inclination of 23°, until it reaches about 17° with respect to the horizon.

Comparing two nozzles, one with a circular cross section and one with a square cross section, the water distribution has resulted similar and in both cases by increasing the water pressure and increasing the speed of rotation, by coiling the spring to the maximum, there is a better water distribution but the amount of water in proximity to the sprinkler greatly increases.

By adopting a nozzle with a starting square cross section and ending with a rectangular cross section as mentioned above, these inconveniences are avoided and in addition there is a better jet throw atomization, a reduced consumption and a better distribution of the water.

The invention will be better understood by follow the description and the attached drawings which show a practical non-limiting embodiment of the invention. In the drawings: Figs. 1 and 2 show in a longitudinal section and in a view along line 11-11 of Fig. 1, the traditional solution of an inclined nozzle ; Figs. 3 and 4 show in a longitudinal section and in a view along the line IV-IV of Fig. 3 a solution according to the invention with a rectangular cross section and with a reduced final inclination of the inferior surface of the water flow opening of the nozzle, which is a rotating one; Figs. 5 and 6 show water distribution patterns obtained with the two nozzles of Figs. 1 and 2; Figs. 7 and 8 show, like Figs. 3 and 4, a modified embodiment for a static sprinkler.

In Fig. 1 a traditional nozzle of a kind that is commonly used for agricultural irrigation is shown, with an inclination e. g. of 23° with respect to the horizon. This traditional nozzle has an axis of symmetry X-X of the portion of the water flow opening having a circular cross section; it has been ascertained that the pluviometry i. e. the water distribution per surface unit has a progression as is shown in Fig. 5, where the horizontal axis shows the distance from the sprinkler-e. g. in meters-and the vertical axis shows the quantity of water that falls along the sprinkler trajectory in millimiters, with the nozzle of Figs. 1 and 2, i. e. one which is symmetrical the X-X axis. It shall be noted that the amount of waterfall per surface unit is rather irregular

particularly at a distance of about 2 meters from the sprinkler, where there is a great decrease in waterfall, and at a distance of about eight meters where there is a sharp increase in waterfall, which immediately falls sharply at a distance from nine meters up to the outer extremity of the jet, which usually reaches approximately 15 meters at the maximum. This irregularity causes a difference of irrigation and thus a difference in the development of the crop for which the irrigation is used; this irregularity can cause an excessive water consumption if sufficient irrigation for the areas (around the two meter distance and around the nine meter distance) is to be obtained where there is a reduced waterfall, or a lack of irrigation in the areas showing low waterfall.

In both cases drawbacks exist due either to excessive irrigation (and therefore an excess in irrigation water consumption) or conversely lack of irrigation.

The invention, therefore, has the object of obtaining the maximum possible uniformity of waterfall along all of the trajectory of the sprinkler waterthrow; a nozzle morphology has been experimentally developed, that has surprisingly given particularly effective results with regards to the uniformity of waterfall, and has also resolved the problem of excess waterfall in the area closest to the sprinkler.

For this purpose a nozzle morphology has been developed which in an embodiment shown in Figs. 3 and 4 has resulted particularly suitable for an angularly movable nozzle, with a spoon-shaped deflector arm on which the same irrigation water jet acts, in order to cause alternate angular movements of the sprinkle, as known in the art.

Unlike traditional nozzles that have a basically circular cross section, the nozzle according to the invention has an initial portion of the nozzle that has a first water flow opening 12 of a shape whatsoever, which develops into a portion 14 having a rectangular but nearly square cross section, i. e. having both the vertical sides and the horizontal sides of the cross section of approximately the same length. Instead in the last segment of the nozzle, the inferior surface 14A of the portion 14 has a lowered zone 14B with an inclination which is reduced compared to the inclination of portions 12 and 14 having an Y-Y axis of the water flow opening. More particularly, considering a

starting inclination of 23° with respect to the horizon of the flow passage, i. e. of the axis Y-Y, zone 14B is lowered until it takes an angle of 17° with respect to the horizon, i. e. with a reduction by 6° of the inclination of the flow passage of the nozzle.

Therefore, the last zone of portion 14 of the nozzle flow passage is rectangular as shown in Fig. 4. The starting portion 12 having substantially an usual morphology is jointed to portion 14 which has a substantially square cross section, and said portion 14 can have a longitudinal extension e. g. in the range of between 4 and 7 or 8 mm and more particularly of approximately 5 mm. The end zone 14B, which is lowered as mentioned above, can have a longitudinal extension with respect to the development of the flow passage in the range of e. g. 2 mm.

By means of a morphology as above described, a waterfall pattern, i. e. a pluviometry of the jet is obtained as depicted in solid line in Fig. 6; the curve of Fig. 5 is plotted in Fig. 6 as well with a dotted fine. By comparing the two lines a substantially uniform distribution of irrigation water in the area between two meters and ten or eleven meters from the sprinkle nozzle can be observed, compared to the irregularity shown by the curve of Fig. 5, in correspondence of the two meters, eight meters and nine meters distance.

From all the above the conclusion can be drawn that a much more uniform irrigation is obtained without excessive or lacking irrigation in the whole range of the sprinkle, being it a static one or an angularly and alternately movable one. It should further be noted from a comparison between the two curves in Fig. 6 that also near the nozzle, within a one meter distance therefrom, a reduction in the amount of waterfall is achieved, when a morphology according to Figs. 3 and 4 is used; a circumstance which could at first glance seem in contrast with what one would expect from such a morphology.

In Figs. 7 and 8 another embodiment of the invention is shown, which is particularly suitable for sprinklers without a deflector, i. e. fixed splinkers. In this embodiment as well, after an initial jointing portion 22 a final portion 24 is provided that starts out with a rectangular but almost square cross section and continues (similarly to portion 14 of the previous example) up to the

external opening and has a bottom surface with a portion 24A which has a smaller inclination with respect to the axis Z-Z of the main water flow and with a second further inclined portion 24B. For example, with an inclination-of 230 of the main flow axis Z-Z with respect to the horizon, the inclination D of the lower surface 24 in the portion 24A can be approximately 15° and the smaller inclination of the portion 24B could be around 9'witch respect to the horizon, i. e. with a reduction by the angle of 7° in the portion 24 and another 6° in the portion 24B.

In this case as well, basically a result in the same range can be obtained as the one previously discussed with the respect to the comparison made in Fig. 6.

Added to the main advantage of obtaining a greater uniformity of waterfall along the whole trajectory of the water jet and the other advantage of reducing the excessive waterfall in the immediate area of the sprinkler, the arrangement according to the invention offers also the advantage of a greater atomization of the irrigation water, even at relatively low water pressures which is apparently a direct result of the corners of the rectangular cross section compared to the circular cross section of the traditional type nozzles.

All of these surprising results have been obtained and controlled by computerized experiments conducted in specialized laboratories at the University of Pisa, Italy.

It should be understood that the drawings show only an example given as a practical demonstration of the invention, which can be modified both in form and arrangement without departing from the scope of the concept underlying the invention.