Core barrel head assembly
Abstract:
A valve assembly for use in an inner tube member of a core barrel head assembly positionable within a drill string of a drilling apparatus. The piston member of the valve assembly is located between a fluid pressure communication port and a fluid flow port to hold the retracting case in an up position and the latches retracted. After an increased fluid pressure has pushed the piston member past the annular element or bushing, the piston member substantially restricts fluid flow through the bushing and allows the retracting case to move to a down position and extend the latches. If the latches are not extended due to an obstruction or misalignment, the retracting case will prevent the piston member from completely passing through the bushing, thus maintaining high fluid pressure due to the flow ports remaining closed, and indicating to the driller that the latches have not properly latched.
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