Irrigation sprinkler with debris flushing perforated riser

Abstract

A sprinkler includes an outer case having an upper end and a tubular riser telescopically mounted in the outer case for extension and retraction from the upper end of the case. The riser has an upper portion with a plurality of circumferentially spaced apertures sized to allow debris to be carried through the apertures with flowing water. A riser seal is positioned and configured to substantially prevent water from escaping between the riser and the outer case when the riser is extended. A drive assembly is mounted inside the riser and includes a drive shaft that is co-axially mounted at an upper end of the riser and rotates when pressurized water is supplied to the outer case. A cylindrical nozzle housing is co-axially coupled to the drive shaft and is rotatable relative to the riser. The nozzle housing is positioned and configured to define a gap between an outer cylindrical wall of the nozzle housing and a complementary outer cylindrical wall of the tubular riser. The apertures in the upper portion of the riser intersect the gap and are configured and sized to receive pressurized water below the riser seal when the riser is retracted.

1 . (canceled) 
     
     
         2 . A sprinkler comprising:
 an outer case having an upstream end and a downstream end;   a riser having an upstream end and a downstream end, the riser telescopically mounted in the outer case for extension and retraction from the downstream end of the case between an extended position and a retracted position, wherein the downstream end of the riser is positioned outside of the outer case when the riser is in the extended position;   a riser seal surrounding the riser and in sealing contact with an outer wall of the riser and with an inner wall of the outer case, the riser seal configured to inhibit water passage between the riser seal and the outer wall of the riser and between the riser seal and the inner wall of the outer housing;   a drive assembly mounted inside the riser and including a drive shaft that is co-axially mounted at an upper end of the riser and is configured to rotate about an axis of rotation when pressurized water is supplied to the outer case;   a nozzle housing having an upstream end and a downstream end and co-axially coupled to the drive shaft at the downstream end of the riser, a space between the downstream end of the riser and the upstream end of the nozzle housing defining a gap, as measured parallel to the axis of rotation of the drive shaft; and   at least one slot formed in and through the outer wall of the riser and extending from the downstream end of the riser toward the upstream end of the riser, a total length of the at least one slot, as measured parallel to the axis of rotation of the drive shaft, being long enough to span the sealing contact between the riser seal and the outer wall of the riser.   
     
     
         3 . The sprinkler of  claim 2 , comprising a sediment basin defined at least partially by an inner surface of the outer wall of the riser, the sediment basin having an inner wall spaced inwardly from the outer wall of the riser. 
     
     
         4 . The sprinkler of  claim 3 , wherein the at least one slot spans a connection between the nozzle housing and a bull gear of the drive assembly. 
     
     
         5 . The sprinkler of  claim 3 , comprising at least one rib extending between and connected to the inner wall of the sediment basin and the outer wall of the riser. 
     
     
         6 . The sprinkler of  claim 2 , wherein the nozzle housing is rotatable with respect to the riser. 
     
     
         7 . The sprinkler of  claim 2 , comprising a bearing surface between the nozzle housing and a bull gear of the drive assembly, wherein the at least one slot spans the bearing surface. 
     
     
         8 . The sprinkler of  claim 7 , comprising a sediment basin within the riser in fluid communication with the at least one slot and extending upstream of an upstream end of the at least one slot. 
     
     
         9 . The sprinkler of  claim 2 , wherein an upstream end of the at least one slot is positioned outside of the outer case when the riser is in the extended position. 
     
     
         10 . A sprinkler comprising:
 an outer case having an upstream end and a downstream end;   a riser having an upstream end and a downstream end, the riser telescopically mounted in the outer case for extension and retraction from the downstream end of the case between an extended position and a retracted position, wherein the downstream end of the riser is positioned outside of the outer case when the riser is in the extended position;   a riser seal configured to inhibit water passage between the riser seal and an outer wall of the riser and between the riser seal and an inner wall of the outer housing;   a drive assembly mounted inside the riser and including a drive shaft that is co-axially mounted at an upper end of the riser and is configured to rotate about an axis of rotation when pressurized water is supplied to the outer case;   an inner wall of the riser at least partially surrounding the drive shaft;   an annular sediment basin at least partially defined by the outer wall of the riser and the inner wall of the riser;   a nozzle housing having an upstream end and a downstream end and co-axially coupled to the drive shaft at the downstream end of the riser, a space between the downstream end of the riser and the upstream end of the nozzle housing defining a gap, as measured parallel to the axis of rotation of the drive shaft; and   at least one slot formed in and through the outer wall of the riser and extending from the downstream end of the riser toward the upstream end of the riser, the at least one slot configured to facilitate direct fluid communication between the annular sediment basin and an exterior of the riser.   
     
     
         11 . The sprinkler of  claim 10 , wherein a downstream end of the inner wall of the riser is positioned upstream of the downstream end of the riser. 
     
     
         12 . The sprinkler of  claim 10 , wherein the at least one slot spans a downstream end of the drive shaft. 
     
     
         13 . The sprinkler of  claim 10 , wherein the at least one slot spans both a downstream end of the drive shaft and an upstream end of the nozzle housing. 
     
     
         14 . The sprinkler of  claim 10 , comprising a bearing surface between the inner wall of the riser and the upstream end of the nozzle housing. 
     
     
         15 . The sprinkler of  claim 14 , wherein the bearing surface is positioned between upstream and downstream ends of the at least one slot. 
     
     
         16 . The sprinkler of  claim 10 , comprising a plurality of ribs extending within the annular sediment basin between the inner wall of the riser and the outer wall of the riser. 
     
     
         17 . The sprinkler of  claim 10 , wherein the nozzle housing is configured to rotate with respect to the riser. 
     
     
         18 . The sprinkler of  claim 10 , wherein an upstream end of the at least one slot is positioned outside the outer case when the riser is in the extended position. 
     
     
         19 . The sprinkler of  claim 10 , wherein an upstream surface of the annular sediment basin is flat. 
     
     
         20 . The sprinkler of  claim 10 , wherein an upstream end of the at least one slot is positioned downstream of an upstream surface of the annular sediment basin.