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经营范围
发明名称
Mud wiper
摘要
申请公布号
US2215377(A)
申请公布日期
1940.09.17
申请号
US19390271384
申请日期
1939.05.02
申请人
SHELL DEVELOPMENT COMPANY
发明人
PENFIELD CHARLES S.;WARREN URBAN MORGAN
分类号
E21B21/00;E21B33/03;E21B33/08
主分类号
E21B21/00
代理机构
代理人
主权项
地址
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