Title:
Back circulator device
United States Patent 2645288


Inventors:
Deters, Bruce A.
Butler, William W.
Application Number:
US23813451A
Publication Date:
07/14/1953
Filing Date:
07/23/1951
Assignee:
JOHNSTON TESTERS INC
Primary Class:
International Classes:
E21B21/10; E21B49/08
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US Patent References:
2493650Valve device for well conduits1950-01-03
1906891Cement valve1933-05-02