The BT Dual Circulating Sub provides a means of emergency circulation through a Ball operated circulating feature. The Ball operated Valve shifts open when a Ball is dropped to the Tool and pressure is applied to exceed the predetermined shear value of the Valve. Once shifted, circulation is diverted to the annular area. However the Dual Circulation Sub also offers an Overpressure Differential Activated Piston. The Piston activation pressure can be predetermined at surface through Shear Pins.
The Connections on the Subs are manufactured to suit BHA requirements.