Abstract: A device for preventing unwanted objects from entering the ball assembly of a float collar or float shoe and otherwise damaging or plugging the valve mechanism therein is disclosed. The device comprises a screen constructed of expanded metal and rigidly affixed to the interior of the float collar or float shoe above the ball valve assembly. The screen portion is either mounted to the interior surface of the float collar sleeve by an annular structural member or mounted to a structural band which is partially embedded in the concrete portion of the float collar or casing guide shoe.

Abstract: A device for insuring a positive fluid seal between a float collar valving element and valve seat therein is disclosed. The device comprises a rubberlike tension strap or compression steel spring positioned within the float collar valve assembly for urging the valving element against the upper valve seat. Fluid pressure from above the valve assembly will overcome the force exerted on the valving element by the urging device and permit fluid to flow in a downwardly direction through the float collar valve assembly. However, when this fluid pressure above the float collar is reduced, the urging device overcomes the force exerted thereby and again urges the valving element in positive sealing engagement with the upper valve seat to preclude flow of fluid in an upperwardly direction back through the float collar valve assembly.