Title: Injection sub for dual tube drilling

Abstract: An injection sub for use with a string of dual concentric drill pipe, having inner and outer tubular members concentrically arranged to mate with the inner and outer pipes of the drill string to provide continuous isolated annular and central passageways, is particularly characterized by an annular chamber in the inner member. Ports permit the flow of fluid from the annular passageway to the chamber, and apertures permit fluid flow from the chamber to the central passageway. An annular check valve in the chamber cooperates with the ports to prevent flow from the chamber to the annular passageway.

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Inventors: Ford, George Alan (Houston, TX, US)

Application Number: 621655
Filing Date: 1975-10-14
Publication_date: 1976-09-07
Assignee: Walker-Neer Manufacturing Co., Inc. (Wichita Falls, TX)
Primary Class(es): 166/325 137/155, 175/215
Other Classes:
US Patent Ref:

2228318	Jan, 1941	Klise	137/155.
3208539	Sep, 1965	Henderson	175/215.
3268017	Aug, 1966	Yarbrough	175/215.
3496953	Feb, 1970	Garrett	137/155.
3937280	Feb, 1976	Dinning	166/242.

Other Refs:
Primary Examiner: Leppink, James A.
Assistant Examiner:
Attorney: Hume, Clement, Brinks, Willian, Olds & Cook, Ltd.