Abstract: This invention relates to a retrievable bridge plug for use in down-hole casing or tubing conduit. A problem exists in known plugs, namely slippage thereof within the casing resulting in breakage of a seal therebetween. The present invention provides a plug which can be set by urging outermost and innermost cylindrical members relative to one another in their longitudinal directions in so doing anchoring slips 19a, 19b and locating a packing element 11a, 11b on an inner surface of the casing, biasing means 30a, 30b providing a predetermined force to the packing element 11a, 11b greater than that required to provide a seal whereby the plug is retained within the casing.

Abstract: A ball type safety valve mounted in a movable cage for automatically closing a subterranean well conduit is disclosed. The ball has a central flow passage which can be aligned with the tubing to permit production and can be automatically rotated to block the tubing. The ball is moved from its closed to its open position by an increase in control fluid pressure, preferably in an external control fluid line extending to the surface of the well. An increase in control fluid pressure causes the cage to move axially and rotation is imparted by the offset camming means attached to a stationary base member. The base member is adjustable relative to the valve housing and to the cage to insure that the valve is fully open and fully closed at opposite extremes of the travel of the cage and ball assembly.