Reverse circulation down-the-hole drill
US5685380A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 29, 1995 |
| Grant date | Nov 11, 1997 |
| Priority date | — |
| Expiry date | Dec 29, 2015 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B21/12
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A reverse circulation down-the-hole drill includes an outer wear sleeve (1) and a backhead (2) assembly located at one end of the outer wear sleeve (1) for connecting the drill to a double-walled drill string and to a source of pressure fluid to actuate the drill. A fluid diverter (5) is mounted inside the outer wear sleeve (1) adjacent to the backhead (2). An inner tube (9), concentric with the outer wear sleeve (1) and extending into the fluid diverter (5), defines at least part of a central return passageway in the drill. A bit (10), located by a chuck (3) at the other end of the outer wear sleeve (1), is slidably mounted on the inner tube (9) in an annular chamber (28, 30) defined by the outer wear sleeve, by the inner tube, by the diverter at one end (28), and by the bit at the other end (30). An inner cylinder (6) mounted inside the outer wear sleeve (1) towards said one end (28) of the chamber adjacent to the diverter defines a fluid communication passage (8) between the diverter and the chamber via porting elements (26, 27). A piston (14) is slidably disposed in the annular chamber (28, 30) with respect to the inner cylinder (6) so as to co-operate with the porting elements…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.