Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor (freeing objects stuck in boreholes by flushing E21B31/03)

Child Classifications

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• E21B 21/001 CPC only CPC only
• E21B 21/002 CPC only CPC only
• E21B 21/003 CPC only CPC only
• E21B 21/01 Arrangements for handling drilling fluids or cuttings outside the borehole, e.g. mud boxes since 2000 +2 CPC IPC+CPC Available in IPC and CPC
• E21B 21/02 Swivel joints in hose-lines IPC+CPC Available in IPC and CPC
• E21B 21/06 Arrangements for treating drilling fluids outside the borehole since 1980 +3 CPC IPC+CPC Available in IPC and CPC
• E21B 21/08 Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure (valve arrangements therefor E21B21/10) since 1980 +2 CPC IPC+CPC Available in IPC and CPC
• E21B 21/10 Valve arrangements in drilling-fluid circulation systems since 1980 +2 CPC IPC+CPC Available in IPC and CPC
• E21B 21/12 using drilling pipes with plural fluid passages, e.g. closed circulation systems since 1980 IPC+CPC Available in IPC and CPC
• E21B 21/14 using liquids and gases, e.g. foams since 1980 IPC+CPC Available in IPC and CPC
• E21B 21/16 using gaseous fluids (E21B21/14 takes precedence) since 2000 IPC+CPC Available in IPC and CPC
• E21B 21/18 Preventing exhaust air from the drill motor from blowing-off towards the working face since 2000 IPC+CPC Available in IPC and CPC