The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 14, 1976
Filed:
Jan. 31, 1975
Applicant:
Inventor:
Fred K Fox, Houston, TX (US);
Assignee:
Engineering Enterprises Inc., Houston, TX (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21B / ; F16K / ;
U.S. Cl.
CPC ...
175107 ; 137857 ; 166325 ; 166326 ; 175234 ; 175243 ; 175323 ; 175340 ;
Abstract
Apparatus is disclosed wherein a tubular body connectible in a drill string and having a float valve arranged therein to normally close the string, as the string is lowered into a well bore, is provided with a plurality of ports connecting its bore above the float valve with its exterior, and valve means for movement from a position normally closing to a position opening the ports when the exterior fluid pressure exceeds the fluid pressure in the bore above the float valve by a predetermined amount.