Patent ID: 7337982

Claim:
A center pivot irrigation system, comprising: a center pivot structure including a vertically disposed water supply pipe having upper and lower ends and inner and outer surfaces; said water supply pipe being fluidly connected to a source of water under pressure; said water supply pipe having a plurality of radially spaced water discharge openings formed therein below its said upper end; a first collar rotatably embracing said water supply pipe below said water discharge openings; said first collar having upper and lower ends and inner and outer surfaces; said first collar having an outwardly presented shelf formed in said outer surface thereof intermediate said upper and lower ends thereof; a first annular flexible seal, having inner and outer ends, positioned at the upper end of said first collar; said first annular flexible seal being in sealing engagement with said outer surface of said water supply pipe to prevent the flow of water downwardly between said first collar and said water supply pipe; a T-connector including a vertical pipe portion having an inner surface, an outer surface, an upper end and a lower end, said T-connector including a horizontal pipe portion extending from said vertical pipe portion; said horizontal pipe portion having an inner end, an outer end, an inner surface and an outer surface; said vertical pipe portion of said T-connector rotatably embracing said water supply pipe; said lower end of said vertical pipe portion of said T-connector being in engagement with said shelf on said first collar and being fixed to said first collar for rotation therewith; a second collar having upper and lower ends and inner and outer surfaces; said second collar having an outwardly presented shelf formed in said outer surface thereof intermediate said upper and lower ends thereof; said upper end of said vertical pipe portion being in engagement with said shelf formed in said outer surface thereof and being fixed to said collar for rotation therewith; a second annular flexible seal positioned at said lower end of said second collar; a first span structure including a water delivery pipe with inner and outer ends; said inner end of said first span structure being in fluid communication with said outer end of said horizontal pipe portion of said T-connector; a second span structure including a water delivery pipe with inner and outer ends; said inner end of said second span structure including an elbow pipe connector having vertical and horizontal pipe portions; said vertical pipe portion of said elbow pipe connector having inner and outer surfaces; said vertical pipe portion of said elbow pipe connector being rotatably received by said upper end of said second collar; said second flexible seal being in sealing engagement with said outer surface of said vertical pipe portion of said elbow pipe connector; each of said first and second span structures being supported upon at least one self-propelled drive unit.