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公开(公告)号:US2578056A
公开(公告)日:1951-12-11
申请号:US535248
申请日:1948-01-30
Applicant: OIL CT TOOL COMPANY
Inventor: FRENCH WALTER P
IPC: E21B33/06
CPC classification number: E21B33/061
公开(公告)号:US2578056A
公开(公告)日:1951-12-11
申请号:US535248
申请日:1948-01-30
Applicant: OIL CT TOOL COMPANY
Inventor: FRENCH WALTER P
IPC: E21B33/06
CPC classification number: E21B33/061