Abstract:
A nozzle is provided for use with a fluid discharge conduit to disperse a fluid flowing through the fluid discharge conduit in a stream. The nozzle includes an orifice housing having a first end for connection to the fluid discharge conduit, a second end with an orifice therein and a communicating passage therethrough to permit the fluid stream to enter from the fluid discharge conduit and to exit from the orifice housing. The communicating passage has a first diameter at the first end adjacent to the fluid discharge conduit and a step formed therein spaced a distance from the orifice to provide a diameter less than the first diameter.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The invention relates primarily to nozzles, and in particular to an irrigation nozzle.  
           [0002]    Nozzles for irrigation systems are well known and a state of the art nozzle is disclosed in U.S. Pat. No. 4,346,848, incorporated herein by reference. In the nozzle disclosed in that patent, an orifice housing is threaded into the discharge end of a sprinkler and an orifice plate is pressed fit or staked into the orifice housing. That patent describes various configurations of the orifice plate which provide improved water distribution.  
           [0003]    Improved water distribution from the nozzle would provide that the amount of water per unit area would be directly proportional to the distance from the sprinkler. In attempting to achieve the most effective distribution pattern, it would be preferred if the water pressure supplied to the sprinkler could be reduced, in order to reduce the power requirements of the irrigation system. It is also preferred to increase a water droplet size from the nozzle in order to improve the usefulness of the water for irrigation purposes. Extremely small droplets result in water vaporizing and failing to reach the ground and very small droplet size results in the water evaporating as it lies on the ground before it can penetrate the soil.  
           [0004]    While the invention disclosed in U.S. Pat. No. 4,346,848 provided an improved nozzle for irrigation, it would be beneficial if there were provided a nozzle which would deliver the stream of water further from the nozzle, or with more uniformity, without increasing the pressure of the water supply to the nozzle.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention yields an improved water distribution in terms of distributing water further from the nozzle and with greater uniformity than prior nozzles, without increasing the water pressure supplied to the nozzle. At least one internal step, which may be in the form of a raised ring, is provided in the orifice housing, in the water passage leading to the orifice plate. It is believed that this step creates a turbulence around the outside of the water stream as it approaches the orifice plate which slows down the outside of the stream, more effectively stripping water from the outer core of the stream as it flows through the slots of the orifice plate. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0006]    [0006]FIG. 1 is a side view, partly in section and partly in elevation, of a first embodiment of the nozzle of the present invention.  
         [0007]    [0007]FIG. 2 is a side view, partly in section and partly in elevation, of a second embodiment of the nozzle of the present invention.  
         [0008]    [0008]FIG. 3 is a side view, partly in section and partly in elevation, of a third embodiment of the nozzle of the present invention.  
         [0009]    [0009]FIG. 4 is a graphical illustration of a water distribution pattern for a prior art nozzle.  
         [0010]    [0010]FIG. 5 is a graphical illustration of a water distribution pattern for a nozzle embodying the principles of the present invention, and of the first embodiment type of FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0011]    [0011]FIG. 1 shows a discharge end  10  of a sprinkler, especially of an impulse rotating sprinkler. Impulse rotating sprinklers are well known in agricultural and residential use. Although the nozzle of the present invention is designed primarily for impulse rotating sprinklers, the nozzle has other applications in other types of sprinklers, and it may also be used for distribution of other fluids.  
         [0012]    The discharge end  10  of the sprinkler delivers fluid from a source of fluid from an upstream end  11  to a downstream end  12  in a fluid stream along a predetermined path substantially concentric to a longitudinal axis  13  of the substantially cylindrical discharge end  10  of the sprinkler. A nozzle or orifice housing  14  may be threaded into the discharge end  10  via mating threads  15  and a hex projection  16  of the orifice housing  14  facilitates threading and tightening the orifice housing  14  into the discharge end  10  of the sprinkler. Other types of connections between the discharge end  10  and the orifice housing  14 , including bayonet, friction fit, set screws, and adhesives, and other connections as are known in the art could also be utilized.  
         [0013]    An orifice plate  20  with an orifice  21  therethrough is mounted in the downstream end  12  of the orifice housing  14 . The orifice plate  20  is pressed fit or staked into the orifice housing  14  and fits in a groove  17  of the orifice housing  14 . The particular configuration of the orifice  21  and the shape of the orifice plate  20  can vary and may include any one of the shapes described in U.S. Pat. No. 4,346,848, or other shapes. The orifice may also be formed in an end wall formed integrally with the orifice housing  14 , in the location of the orifice plate  20 . If a separate orifice plate is used, it can be formed of a different material than the orifice housing, particularly for wear and cost considerations.  
         [0014]    The liquid to be dispensed by the nozzle flows through an interior of the discharge end which is bounded by an interior surface  30  substantially parallel with the longitudinal axis  13 , thus providing a generally cylindrical chamber  31 . While a generally circular cylindrical chamber  31  yields the highest inner stream velocity and is easiest to form in a metal orifice housing  14 , other shapes could be provided This surface  30  has a diameter substantially identical to an interior cylindrical surface  32  formed at an upstream end of the orifice housing  14 . Thus, liquid flowing from the discharge end  10  into the orifice housing  14  will proceed substantially unhindered. As the fluid approaches the orifice plate  20 , there is a step  34  provided in the interior of the orifice housing  14  which reduces the internal diameter of the passage through the orifice housing. The step shown in FIG. 1 is a single continuous ring  36  extending around the interior circumference of the orifice housing  14 . Alternatively, as shown in FIG. 2, there may be provided a plurality of rings  36   a  as the step  34 . Further, as shown in FIG. 3, there may be provided a discontinuous ring  36   b  as the step. Other turbulence creating structures could be used as well for the step  34 . The single ring of FIG. 1 is the easiest to form in a metal orifice housing  14 .  
         [0015]    While the size and placement of the step  34  may vary, it has been found that in an orifice housing  14  having an internal diameter at surface  32  of 0.555 inches, the step  34  preferably has an internal radial dimension, or height, in the range of 0.015 to 0.045 inches. The particular dimension selected depends on the orifice plate diameter and the intended water pressure at the sprinkler. Also, a leading edge  38  of the step  34  may be positioned a distance from the orifice plate  20  selected to provide the most effective and desired range for the water spray. In the particular size orifice housing described above, a distance of 0.109 inches provides a beneficial result.  
         [0016]    If desired, stream straighteners  40 , as are known in the art, can be placed in the interior of the orifice housing  14  in the chamber  31 , to hold a center of the stream together, even though a turbulence is created at an outside of the stream due to the presence of the step  34 . A shoulder  42  may be provided for the stream straightener to abut against, thereby avoiding the need for separate fasteners.  
         [0017]    In tests of a nozzle incorporating the principles of the present invention, that is, with the use of the internal step, compared to a previously available nozzle without such a step, the water distribution pattern was improved according to the following charts.  
         [0018]    The first chart listed below and graphically illustrated in FIG. 4 shows the results of a standard prior art nozzle. The amount of water collected at various listed distances from the nozzle, per hour with a nozzle size of 9/64″ and a water flow rate of 2.9 gallons per minute, with a pressure of 30 PSI is listed.  
                                                2.0′ = 0.185   14.0′ = 0.083    26.0 = 0.065   38.0′ = 0.025        4.0′ = 0.115   16.0′ = 0.050   28.0′ = 0.075   40.0′ = 0.003        6.0′ = 0.085   18.0′ = 0.035   30.0′ = 0.085        8.0′ = 0.070   20.0′ = 0.040   32.0′ = 0.090       10.0′ = 0.070   22.0′ = 0.045   34.0′ = 0.085       12.0′ = 0.075   24.0′ = 0.055   36.0′ = 0.060                  
 
         [0019]    The second chart listed below and graphically illustrated in FIG. 5 shows the results of a nozzle as shown in FIG. 1, embodying the principles of the present invention. The amount of water collected at various listed distances from the nozzle, per hour with the same size nozzle, water flow rate and pressure as in chart 1 is listed.  
                                                2.0′ = 0.133   14.0′ = 0.093    26.0 = 0.067   38.0′ = 0.037        4.0′ = 0.113   16.0′ = 0.093   28.0′ = 0.067   40.0′ = 0.013        6.0′ = 0.093   18.0′ = 0.083   30.0′ = 0.067        8.0′ = 0.087   20.0′ = 0.073   32.0′ = 0.073       10.0′ = 0.087   22.0′ = 0.067   34.0′ = 0.067       12.0′ = 0.087   24.0′ = 0.067   36.0′ = 0.057                  
 
         [0020]    As seen, the results with a nozzle embodying the principles of the present invention are much more consistent throughout the range, and in fact, the nozzle embodying the principles of the present invention had a radius of throw 2 feet further than the prior art nozzle. With a more uniform pattern throughout the range, the results of the plants being watered will also be more uniform and areas of over watering will be avoided as will areas of under watering.  
         [0021]    The present invention has been described utilizing particular embodiments. As will be evident to those skilled in the art, changes and modifications may be made to the disclosed embodiments and yet fall within the scope of the present invention. The disclosed embodiments are provided only to illustrate aspects of the present invention and not in any way to limit the scope and coverage of the invention. The scope of the invention is therefore only to be limited by the appended claims.