Utility
Subclass Subgroup Patent
C09K 8/424 09809737
D01D 11/06 09809906
E04H 17/16 09809994
E21B 43/261 09810051
F16K 31/1223 09810343
G10K 11/346 09812118
Design and Plant
Class Subclass Patent
D12 101 D0801874