Patent ID: 6135216
Filing Date: 2000-10-24
Classification: E21B

Abstract:
A sealing and venting system for a drill assembly including a casing, a fluid distributor disposed within the casing and including an elongated guide portion having an outer surface, a piston slidably disposed within the casing and having first and second ends and an interior surface defining a passage between the piston ends, the piston interior surface being disposeable about the outer surface of the guide portion, the system comprising:a sealing surface disposed within the piston passage and slidably engageable with the outer surface of the guide portion so as to provide a seal between the piston and the distributor; andan exhaust passage defined by sections of the interior surface of the piston and of the outer surface of the guide portion when the guide portion is disposed within the piston passage, the passage extending between the sealing surface and the second end of the piston.