GB1453008A - Well-head assemblies - Google Patents

Abstract

1453008 Wells etc F M C CORP 10 Oct 1974 [3 Dec 1973] 43857/74 Heading E1F A well casing head assembly 10 has a straight through bore 27, an internal annular recess 42 in the bore 27, a split ring retractile seat element 12 positioned in the recess 42 which is inherently biassed towards a contracted condition in which it extends into the bore 27 to support a pipe or other member, e.g. casing hanger 64, and cam means 14 for expanding the split ring 12 into a retracted position within the recess 42. The split ring 12 has axial grooves 52 to increase its flexibility, a fiange 62 which retains the ring 12 in the recess 42, a conical surface 60 which centers the ring 12 when the hanger 64 is landed on it, and a conical surface 66 which acts as a cam surface to allow full bore well tools to be pulled upwardly through the ring 12 when the ring 12 extends into the bore 27. The split ring 12 can be expanded to retract it into the recess by rotation of a cam 70 (Fig. 6) positioned between the ends 44, 46 of the ring 12. The cam 70 is rotated by means of square-end 114 on shaft 72, the two operative positions of the cam 70 being determined by pins 96, 98 engaging stop surfaces (not shown) on member 82. The cam 70 can be locked in the position in which it holds the ring 12 in its retracted position within the recess by means of a split pin (not shown).