DIFF Subgroup
E21B 21/10 Valve arrangements in drilling-fluid circulation systems
Introduced: January 1980
Title
Titles differ between systems:
IPC: Valves arrangements in drilling-fluid circulation systems
CPC: Valve arrangements in drilling-fluid circulation systems
Full Title
Full titles differ between systems:
IPC:
Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor > Valves arrangements in drilling-fluid circulation systems
CPC:
Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor (freeing objects stuck in boreholes by flushing E21B31/03) > Valve arrangements in drilling-fluid circulation systems
Of 2 combined children, 0 exist in both systems.
2 codes are CPC-only extensions.
Child Classifications
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