Dual flow passage drill stem
US4067596A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 25, 1976 |
| Grant date | Jan 10, 1978 |
| Priority date | — |
| Expiry date | Aug 25, 1996 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16L9/18
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
Dual flow passage drill stem has a tube radially supported within a drill pipe by a plurality of metal ribs welded to the middle portion of the tube and by elastomer O-rings mounted in spiders disposed around the tube connectors and seated against outwardly facing shoulders in the pipe tool joints. Axial loads are taken by elastomer rings around the tube connectors clamped between outwardly facing annular rabbets at the inner periphery of each spider and an integral flange on the pin tube connector and a threaded flange screwed onto box tube connector. The tube is preloaded in tension and the pipe and elastomer rings are preloaded in compression. The axial support elastomer rings preferably have hour-glass cross sections to increase their damping effect; in addition, the axial support elastomer rings, as well as the radial support O-rings, are preferably made of neoprene, which has a relatively flat curve of force transmission versus frequency. Desirably the elastomer mounted tube has a resonant frequency different from that of the expected cyclic loading of the pipe, e.g., when employed with a vibratory or hammer drill motor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.