US Patent 7699111 Float collar and method

A float collar 10 includes a housing 12 and a generally sleeve-shaped elastomer 20. The lower plate 30 and an upper plate 32 are each supported on an elongate rod 22, and at least one of the plates is axially fixed relative to the tubular housing. The plate intended for exposure to fluid pressure includes a plurality of arcuate flow ports 34 for communication with the annulus between the tubular housing and the elastomer prior to swelling of the elastomer.