DIFF Subgroup
E21B 17/08 Casing joints
Introduced: September 1968
Full Title
Full titles differ between systems:
IPC:
Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Casings; Tubings > Couplings; Joints > Casing joints
CPC:
Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Casings; Tubings > Couplings; joints > Casing joints
Of 1 combined children, 0 exist in both systems.
1 codes are CPC-only extensions.
Child Classifications
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