Patent ID: 6105669
Filing Date: 2000-08-22
Classification: E21B

Abstract:
A device for closing an upper open end of a cylindrical well casing, comprising:a. an annular elastomeric sealing gasket having an inner diameter selected for complemental fitting of said gasket around said cylindrical well casing exterior;b. a base having an upwardly facing circumferential groove for receiving a lower portion of said gasket therein and having a circular opening slightly larger than the exterior diameter of the well casing positioned coaxially with and below said groove permitting the base to be positioned about the upper end of the well casing, further comprising:i. a plurality of lugs positioned about the outer periphery of said base, extending radically outwardly therefrom and being integrally constructed therewith, said lugs having non-circular downwardly facing recesses formed therein and being equiangularly positioned about the periphery of said base;ii. an annular flange projecting downwardly from the lower surface of said base, concentrically arranged with respect to said opening and having a cylindrical inwardly facing surface extending axially downwardly from said groove;iii. said groove having an annular inwardly facing wall surface parallel with said flange inner surface and an axially upwardly facing shoulder surface perpendicular to said flange inwardly facing surface and connecting said flange inwardly facing surface with said groove annular surface; andiv. said base having an axially upwardly facing surface adjoining said groove annular surface;v. upper surface extremities of said lugs being coplanar and axially facing, parallel with said base axially upwardly facing surface; andc. a cap having a downwardly facing circumferential groove for receiving an upper portion of said gasket therewithin, comprising;i. a plurality of lugs positioned about the outer periphery of said cap, extending radially outwardly therefrom and being integrally constructed therewith, said lugs having non-circular upwardly facing recesses formed therein and being equiangularly positioned about the periphery of said well cap for axial alignment with lugs of said base;ii. an inwardly facing annular surface parallel with said flange cylindrical inwardly facing surface;iii. an axially downwardly facing shoulder surface perpendicular to said annular inwardly facing surface;iv. said lugs of said base and said cap being adapted for axial alignment with axial apertures formed in respective ones of said lugs being axially aligned; andv. fastener means within said apertures for urging said cap and said base towards one another thereby compressing said gasket between said shoulder surfaces and causing said gasket to deform radially inwardly thereby providing a seal about said cylindrical well casing.