Earth boring apparatus
US8997891B2 · kind B2 · utility
1Cited by
2References
19Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | May 5, 2011 |
| Grant date | Apr 7, 2015 |
| Priority date | — |
| Expiry date | Jul 26, 2033 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B17/003
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An earth boring apparatus includes a drill rod, a source for a drill fluid, and a voltage source. The drill rod has a hollow rod casing provided for throughflow of the drill fluid, and a conductor located within the rod casing, with the voltage source being connected with the conductor and the rod casing. The voltage source is so connected as to prevent the electric conductor to act as anode in the event the drill fluid establishes an electrically conductive connection between the rod casing and the conductor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.