Patent Application
20080054094
Referring to
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 3600 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
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
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.
