REVERSE CIRCULATION DRILL PIPE
Reverse circulation (RC) drill pipe is a dual wall pipe used for uncontaminated, representative and continuous samples. It is also used to reduce air requirements and maintain uphole velocity in larger diameter drilling applications. RC Inlet air passes between the inner tube and outer barrel. Cuttings are evacuated through the center tube.
Foremost manufactures a complete range of reverse circulation drill pipe and accessories including air swivels, saver subs, bit subs, interchanges, wear sleeves, blow-down and blow-back subs and open center bits.
Foremost’s patented inner barrel suspension and retention system eliminates problems arising from the transfer of vibration and torque loads applied to the outer pipe. The inner pipe is suspended within the outer barrel and is relatively unstressed. The o-ring retainers absorb percussion forces and allow for replacement of the inner barrel in the field if required.
To suit customer requirements, Foremost offers various drill pipe configurations, with or without connector tubes:
Concealed Inner Pipe (CIP) – Incorporates a dual tube design, using both an outer barrel and a concealed inner tube. Connector tubes are not required when using CIP drill pipe. The inner tubes are sealed when the outer barrels are threaded together.
Connector Tube Pipe (CTP) – A dual tube design, incorporating an outer barrel and a concealed inner tube. Connector tubes are required when using CTP and are manually connected.
RC Hammer Pipe – The inner tube protrudes from the box tool joint and connector tubes are not required. The inner tubes are sealed when the outer barrels are threaded together.