Mud saver valve

Abstract

A mud-saver valve having an independent means for blocking the flow of fluid through the bore of a ball valve. The mud-saver valve has a tubular body having a central through-bore, a rotatable ball having a through-bore, and pressure actuated right and left concave cup members that can rotate about the periphery of said ball regardless of the position of the ball. When the ball is in the open position, the concave cup members may be rotated from an open to a closed position along the outer surface of the ball, thereby blocking the through-bore of the ball and preventing the flow of fluid through such bore.

1 . A mud-saver valve comprising: 
 a. a ball valve having a closed position and an open position defining a flow path; and    b. means for sealing said flow path when said ball valve is in the open position and the pressure within said flow path is less than a predetermined value.    
   
   
       2 . The mud-saver valve of  claim 1 , wherein said means for sealing said flow path comprises: 
 a. a first concave cup member pivotally mounted about the periphery of said ball;    b. a second concave cup member pivotally mounted about the periphery of said ball, wherein said first and second concave cup members pivot about a common pivot axis;    c. means for closing said first and second concave cup members against one another to obstruct said flow path when the pressure within said flow path is less than a predetermined value.    
   
   
       3 . The mud-saver valve of  claim 2 , wherein said means for closing said first and second concave cup members comprises: 
 a. a substantially cylindrical body having an axial through-bore situated below said ball valve;    b. a first lever attached to said first concave cup member;    c. a second lever attached to said second concave cup member;    d. a piston, slidably disposed within the through-bore of said substantially cylindrical body, wherein said first and second levers are connected to said piston; and    e. a spring biasing said piston toward said ball valve.    
   
   
       4 . A mud-saver valve comprising: 
 a. a substantially cylindrical body having an axial through-bore;    b. a ball having first and second lateral stems and a through-bore, wherein said first and second stems are pivotally mounted to said body about a pivot axis substantially perpendicular to said through-bore of said body, and said ball is rotatably disposed within the through-bore of said body;