DIFF Subgroup
E21B 37/04 operated by fluid pressure, e.g. free-piston scrapers
Introduced: January 1980
Full Title
Full titles differ between systems:
IPC:
Methods or apparatus for cleaning boreholes or wells > Scrapers specially adapted therefor > operated by fluid pressure, e.g. free-piston scrapers
CPC:
Methods or apparatus for cleaning boreholes or wells (E21B21/00 takes precedence) > Scrapers specially adapted therefor > operated by fluid pressure, e.g. free-piston scrapers
Of 1 combined children, 0 exist in both systems.
1 codes are CPC-only extensions.
Child Classifications
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