DIFF Subgroup
E21B 37/02 Scrapers specially adapted therefor
Introduced: September 1968
Full Title
Full titles differ between systems:
IPC:
Methods or apparatus for cleaning boreholes or wells > Scrapers specially adapted therefor
CPC:
Methods or apparatus for cleaning boreholes or wells (E21B21/00 takes precedence) > Scrapers specially adapted therefor
IPC and CPC are identically structured here. All 1 subcodes exist in both systems.
IPC defines codes here since 1980.
Child Classifications
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- E21B 37/04 operated by fluid pressure, e.g. free-piston scrapers since 1980 +1 CPC IPC+CPC Available in IPC and CPC