US 4,378,818 AGranted

Well drilling float valve

OwnerArthur J. Cormier, Jr.inventor

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Abstract

A float valve for use with drill pipe or drill casing or the like in a well is provided wherein a valving flapper can be set in a partially open position while lowering the drill pipe or drill casing into a well thereby allowing the drill pipe or casing to fill with drilling mud or fluid thus preventing inadvertent collapse of the drill pipe or the drill casing. Once the drill string and the valve are fully in the hole, the valving flapper moves, responsive to circulation through the valve bore, from the partially open position to a fully open position allowing the valve flapper to freely pivot thereafter within the provided valve body between fully open and fully closed positions. The valve flapper is thus free to close in a back pressure situation or due to a blowout or for any such other reason. During circulation of drilling fluids or the like, the flapper is maintained in an open flow condition.

Claims11

Dependent claims

A float valve comprising:

a. a valve body having a flow bore therethrough;
b. a valve seat on said valve body at said bore;
c. a flapper valve pivotally mounted on said valve body between fully open flow and fully closed flow positions, with said flapper valve sealing said seat in the fully closed position;
d. spring means cooperatively connected to the valve body and flapper valve for urging the flapper valve toward the fully closed position;
e. pre-settable catch means carried by and movably mounted upon the flapper valve between engaged and disengaged positions for preventing movement of the flapper valve to the fully closed position when the catch means desirably occupies the engaged position as so pre-set, the flapper valve thus assuming a partially open position responsive to both urging of the spring means and the pre-set engaged positioning of the catch means;
and
f. biasing means associated with the catch means for biasing the catch means to the disengaged position when the flapper valve moves from the partially open position to the fully open position, the flapper valve being movable to the fully closed position when the catch means is disengaged.

4 more elements

Dependencies are inferred from the claim text.