Air injection sub
US4171187A · kind A · utility
5Cited by
7References
14Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jul 28, 1977 |
| Grant date | Oct 16, 1979 |
| Priority date | — |
| Expiry date | Jul 28, 1997 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B21/12
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An air injection sub for use with a dual conduit drill pipe string is provided having inner and outer concentric tubular members which are connected to the corresponding inner and outer conduits of a dual conduit string to provide isolated annular and central passageways and is particularly characterized by improved injection means in the inner tubular member which allows fluid to pass from the annular passageway into the central passageway through a plurality of apertures which open into the central passageway at a plurality of levels and angular positions, is field adjustable and provides improved erosion resistance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.