Patent ID: 8100199

Claim:
A fluid circulation valve for use in well drilling with a drill stand and a drill string extending into the well, comprising: a valve housing having a central flow path therein, an upper threaded connector for threaded engagement with a lower end of the drill joint, a lower threaded connector for threaded engagement with the upper end of the drill string, and a housing side port for selective fluid communication with a flow line radially exterior of the valve housing; a ball rotatably positioned within the flow path and having a throughbore and a side port, the ball throughbore being in fluid communication with the housing central flow path and the housing side port closed when the ball is open, the valve housing sealing fluid in the central flow path from above the ball to below the ball; an upper portion of the valve housing central flow path being closed and the housing side port and the ball side port are in fluid communication with a lower portion of the valve housing central flow path when the ball is closed; and an attachment coupling for selectively engaging a wall of the valve housing adjacent the housing side port, the attachment coupling including a retractable sleeve positioned within the coupling outer housing, a fluid circulation sleeve positioned within the retractable sleeve and adapted for sealed engagement with the valve housing, and a plurality of circumferentially spaced interference members acting between the valve housing and the retractable sleeve to secure the fluid circulation sleeve to the valve housing until the retractable sleeve is retracted.