Abstract:
A water distribution plate and diffuser plate assembly for distributing a stream emitted from a sprinkler nozzle comprising: a shaft having one end attached to a sprinkler component and an opposite end supporting first and second plates in axially spaced relationship for rotation about the shaft independent of one another; the first plate located adjacent the nozzle and formed with at least one water distribution groove shaped and arranged to divide a primary stream emitted from the nozzle into a plurality of secondary streams, and the second plate located downstream of the first plate and formed with at least one diffuser element arranged to be struck by at least some of the secondary streams exiting the first plate, and wherein speed of rotation of the first and second plates is braked.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates to rotary sprinklers and, more specifically, to a rotary sprinkler having a stream diffuser driven in random fashion by a stream emitted from a fixed nozzle and redirected by a grooved water distribution plate. 
   Stream interrupters or diffusers per se are utilized for a variety of reasons and representative examples may be found in U.S. Pat. Nos. 5,192,024; 4,836,450; 4,836,449; 4,375,513; and 3,727,842. 
   One reason for providing stream interrupters or diffusers is to enhance the uniformity of the sprinkling pattern. When irrigating large areas, the sprinklers are spaced as far apart as possible in order to minimize system costs. To achieve an even distribution of water at wide sprinkler spacings requires sprinklers that simultaneously throw the water a long distance and produce a pattern that “stacks up” evenly when overlapped with adjacent sprinkler patterns. These requirements are achieved to some degree with a single concentrated stream of water shooting at a relatively high trajectory angle (approximately 24° from horizontal), but streams of this type produce a nonuniform “donut pattern”. Interrupting a single concentrated stream, by fanning some of it vertically downwardly, produces a more even pattern but also reduces the radius of throw. 
   Proposed solutions to the above problem may be found in commonly owned U.S. Pat. Nos. 5,372,307 and 5,671,886. The solutions disclosed in these patents involve intermittently interrupting the stream so that at times, the stream is undisturbed for maximum radius of throw, while at other times, it is fanned to even out the pattern. In both of the above-identified commonly owned patents, the rotational speed of the water distribution plate is slowed by a viscous fluid brake to achieve both maximum throw and maximum stream integrity. 
   There remains a need for an even more efficient stream interrupter or diffuser configuration to achieve more uniform wetted pattern areas. 
   BRIEF DESCRIPTION OF THE INVENTION 
   In the exemplary embodiments of this invention, a water distribution plate and a stream diffuser plate are both mounted for rotation on a single, fixed shaft. The water distribution and diffuser plates rotate independently of one another, however, and both are viscously braked to slow the rate of rotation of the plates. 
   In one exemplary embodiment, a shaft extends upwardly through the nozzle of a sprinkler head or body and supports the water distribution plate and diffuser plate downstream of an arcuate or full circle stream emitted from the nozzle. The water distribution plate is generally cone-shaped and formed with a plurality of grooves that are slightly curved in a circumferential direction so that the stream impinging on the grooves causes the plate to rotate about the shaft. A first stator component is fixed to the shaft and located within a sealed chamber in the water distribution plate, the chamber at least partially filled with a viscous fluid that causes the rate of rotation of the water distribution plate to be significantly slowed in comparison to an unbraked rate of rotation. 
   Downstream of the water distribution plate, the diffuser plate is mounted on the shaft in a similar manner, with a second sealed stator element fixed to the shaft in a chamber at least partially filled with viscous fluid. The diffuser plate is provided with a plurality of diffuser elements projecting downwardly from a peripheral edge of the lower surface of the diffuser. 
   The water distribution plate rotates at a specific and substantially constant speed, while the diffuser plate rotates at an intermittent and random speed. More specifically, the diffuser plate is designed such that when one or more stream components from the water distribution plate impinges on a diffuser element, the stream components break up to fill in the wetted pattern area while at the same time, the diffuser element is driven to a new and random position. In this regard, the diffuser elements are provided with curved vane surfaces that cause the diffuser plate to rotate when struck by stream components emitted from the water distribution plate. 
   In a second exemplary embodiment, the water distribution plate and diffuser plate are again mounted on a single shaft, but the shaft is supported within a cap assembly that is in turn supported on the sprinkler body downstream of the nozzle. Thus, in this embodiment, the shaft does not project upwardly through the sprinkler nozzle. Otherwise, the mounting of the water distribution plate and diffuser plate on the single fixed shaft, and the viscous damping arrangement remains substantially as described hereinabove. 
   Accordingly, in a first aspect, the invention relates to a water distribution plate and diffuser plate assembly for distributing a stream emitted from a sprinkler nozzle comprising: a shaft having one end attached to a sprinkler component and an opposite end supporting first and second plates in axially spaced relationship for rotation about the shaft independent of one another; the first plate located adjacent the nozzle and formed with at least one water distribution groove shaped and arranged to divide a primary stream emitted from the nozzle into a plurality of secondary streams, and the second plate located downstream of the first plate and formed with at least one diffuser element arranged to be struck by at least some of the secondary streams exiting the first plate, and wherein speed of rotation of the first and second plates is braked. 
   In another aspect, the invention relates to a water distribution plate and diffuser plate assembly for distributing a stream emitted from a sprinkler nozzle comprising: a shaft having one end attached to a sprinkler component and an opposite end supporting first and second plates in axially spaced relationship for rotation about the shaft independent of one another; the first plate located adjacent the nozzle and formed with at least one water distribution groove shaped and arranged to divide a primary stream emitted from the nozzle into a plurality of secondary streams, and the second plate located downstream of the first plate and formed with at least one diffuser element arranged to be struck by at least some of the secondary streams exiting the first plate; the first plate formed with a first internal chamber, with a first stator element secured to the shaft and received in the first internal chamber, the second plate formed with a second internal chamber, with a second stator element secured to the shaft and received in the second internal chamber, the first and second internal chambers at least partially filled with a viscous fluid. 
   The invention will now be described in detail in connection with the drawings identified below. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a partial cross section through a rotary sprinkler incorporating a water distribution plate and diffuser plate in accordance with a first exemplary embodiment of the invention; 
       FIG. 2  is a front elevation of a shaft provided with a pair of stator elements as incorporated in the sprinkler shown in  FIG. 1 ; 
       FIG. 3  is a sectioned perspective view of the water distribution and diffuser plates in accordance with the first exemplary embodiment of the invention; 
       FIG. 4  is a partial cross section through a rotary sprinkler in accordance with a second exemplary embodiment of the invention; and 
       FIG. 5  is a sectioned perspective view of the water distribution plate and diffuser plate shown in  FIG. 4 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , a sprinkler head is partially shown at  10 , the sprinkler head incorporating a nozzle  12  and supporting one end of a shaft  14 . The shaft  14  (see also  FIGS. 2 and 3 ) extends out of the sprinkler head, in a downstream direction, and supports a water distribution plate and diffuser assembly  16  for impingement by a stream S emitted from the nozzle. A stream deflector  18  is fixed to the shaft  14  and cooperates to define the nozzle orifice  20 . The deflector guides an arcuate (or round) stream onto the water distribution plate  22  for redirecting the water in a substantially radially outward direction as described further herein. 
   More specifically, the water distribution plate  22  is formed with at least one, but in this embodiment with a plurality of grooves  24  shaped to divide a single vertically-oriented arcuate or full 360° stream (or multi-streams) emitted from the nozzle  12  into a plurality of secondary streams or stream components, and to redirect those stream components in a generally radial direction. Grooves  24  are also curved slightly in a circumferential direction such that the water distribution plate  22  is caused to rotate about the shaft  14  as a result of the plurality of stream components acting on the interior walls of the grooves. Such water distribution plates are well-known in the art. 
   The water distribution plate  22  is also bored and counterbored to receive the shaft  14  and to support a pair of shaft bearings  26 ,  28  within cavities  30 ,  32  on either side or end of a smaller diameter center chamber  34 . Flexible lip seals  36 ,  38  are seated on shoulders  40 ,  42 , respectively, in the bearings, with annular retainers  44 ,  46  press-fit into the cavities to hold the seals in place. Thus, shaft  14  passes through the bearings, seals and retainers, and the distribution plate rotates relative to the shaft. 
   A first disk-like stator  48  is fixed to the shaft  14  at a location where it will be centered within the chamber  34 . The latter is at least partially filled with a viscous fluid (such as a silicone grease), with seals  36 ,  38  preventing escape of the viscous fluid in opposite directions along the shaft. Rotation of the distribution plate  22  is slowed by the viscous shearing of the fluid as the plate rotates relative to the fixed stator  48 . 
   The diffuser  50  includes a substantially solid, cylindrical body  52 , with at least one, but in this embodiment a plurality of diffuser elements  54  projecting downwardly from a peripheral edge of the lower surface  56  of the body  52 . The diffuser elements  54  are circumferentially spaced about the lower peripheral edge of the body  52 , with uniform or nonuniform spaces therebetween. Each element  54  has a curved vane surface  58  (best seen in  FIG. 3 ) that is arranged to interrupt stream components emanating from the grooves  24  in the water distribution plate, and to drive the diffuser plate to a new position. In this regard, note that the elements  54  are substantially laterally aligned with the upper ends of grooves  24 , but recognizing, however, that there are fewer elements  54  than grooves  24 . 
   The manner in which the diffuser  50  is supported on the shaft  14  is generally similar to the manner in which the water distribution plate  22  is supported on the same shaft. Specifically, the diffuser  50  is bored and counterbored to provide a pair of cavities  60 ,  62  on either side of a second, smaller-diameter chamber  64 . The cavities  60 ,  62  accommodate a second pair of shaft bearings  66 ,  68  on opposite sides of the center cavity and flexible lip seals  70 ,  72  are seated on shoulders  74 ,  76 , formed respectively, on the bearings. Retainers  78 ,  80 , hold the respective seals in place. 
   A second, substantially cylindrical stator  82  is fixed to the shaft  14  so as to be centered within the second chamber  64 . A similar viscous fluid fills at least part of the chamber, with seals  70 ,  72  preventing leakage along the shaft. In this way, the rotation of the diffuser plate is also viscously damped or slowed by viscous shearing in the chamber  64 . 
   In use, when the stream components from the water distribution plate  22  impinge on the diffuser elements  54 , the diffuser elements break up the plural stream components to fill in the wetted pattern while at the same time, the diffuser  50  is driven to a new and random position. Thus, the water distribution plate  22  and diffuser  50  rotate about the shaft  14  completely independently of each other. Note that while shaft  14  is normally fixed, i.e., nonrotatable during operation, there may be instances where the shaft is rotatable in an adjustment mode to, for example, throttle flow to the nozzle. In any event, the water distribution plate  22  will rotate substantially continuously as the stream S impinges on the grooves  24 . The diffuser  50 , on the other hand, will only move when stream components from the water distribution plate grooves  24  strike a vane surface  58  of a diffuser element  54  causing the diffuser  50  to rotate to a different position. The stator  82  is sized to provide enough braking of the diffuser  50  to ensure that it rotates slower than plate  22 . Since the number of diffuser-elements is less than the number of grooves in the water distribution plate  22 , not all secondary streams leaving the water distribution plate are diffused, and thus the diffuser plate will rotate intermittently to random positions, thus enhancing uniformity of the wetted pattern area. 
   The commonality between the water distribution plate  22  and the diffuser  50  is the way in which they handle loads. Both stator elements  48 ,  82  are designed so that with compression loads, the two bearings on either side of these elements are pressed on either side to allow little or no movement. The two plastic bearings also handle axial loading. 
   A second embodiment of a combined water distribution plate/diffuser assembly  84  is shown in  FIGS. 4 and 5 . In this embodiment, a more sharply defined conically-shaped water distribution plate  86  is supported at one end  88  of a fixed shaft  90 . Thus, shaft end  88  terminates within the water distribution plate. A diffuser plate  92  provided with diffuser elements  94  is supported on the shaft  90  adjacent the water distribution plate, and the opposite end  96  of the shaft  90  is fixed within, for example, a cap assembly  98  that is typically supported above (or below) a sprinkler body  99  by one or more struts (not shown). In this instance, a nozzle  100  emits a single solid stream S that is located upstream of the water distribution plate  86 , and the shaft  90  forms no part of, nor does it extend through, the nozzle supported in the sprinkler body. 
   The water distribution plate  86  is formed with grooves  102  that redirect the stream and that cause the plate to rotate on the shaft, but here, the grooves continue to an apex  104  on which the solid stream S impinges and breaks up into secondary streams or stream components that flow through the grooves  102 , causing rotation of the plate  86 . 
   The one end  88  of shaft  90  is received in a blind bore  106  formed in the plate  86 , with a thrust bearing  108  interposed between the shaft end and the end face  110  of the bore. The blind bore  106  is counterbored to form a cavity  112  that receives a first substantially cylindrical stator  114 , a shaft bearing  116 , flexible lip seal  118  and retainer  120 . A fluid chamber  122  is defined between end face  124  of the cavity  112  and the bearing  116  in which the stator  114  is located. The chamber is at least partially filled with a viscous fluid. The lip seal  118 , seated on bearing shoulder  126 , prevents escape of the fluid along the shaft. 
   The diffuser  92  is formed with a centerbore  128  through which the shaft  90  passes. The shaft also passes through a pair of shaft bearings  130 ,  132  located in the bore  128 , defining a second fluid chamber  134  that receives a second substantially cylindrical stator  136  fixed to the shaft. The chamber  134  is at least partially filled with a viscous fluid, with leakage prevented by flexible lip seals  138 ,  140  seated on respective shoulders  142 ,  144  of the bearings  130 ,  132 . Annular retainers  146 ,  148  hold the seals and bearings in place. 
   In use, the main or primary solid stream S impinges on the grooves  102 , forming plural, fully developed secondary streams or stream components that exit the distributor (or first) plate  86  in radial directions. The speed of rotation of the plate  86  is desirably slowed by the shearing action between the silicone fluid in chamber  122  and the first stator  114 . The exact speed of rotation can be controlled by the viscosity of the fluid. 
   When one or more stream components from the water distribution plate  86  strikes a vane surface  150  on a diffuser element  94 , the stream components are further broken up to fill in the wetted or distributed pattern and thus establish better uniformity, while at the same time, the diffuser plate  92  is driven to a new random position, due to the difference in number and spacing of the diffuser elements  94  relative to grooves  102 . Thus, as in the first-described embodiment, plates  86  and  92  rotate completely independently of each other and at different speeds. 
   It will be appreciated that equivalents to the viscous damping arrangements disclosed herein may be employed to slow the rotation of one or both of the water distribution and diffuser plates. For example, a friction brake or a gear train may be employed to slow the rotation speed of the plates. 
   While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.