| 摘要 |
A fitting for engagement with a drill string or further fitting comprises an inner section (30) for securement to a drill string or further fitting, an outer section (31) for securement about said inner section and rotatable relative thereto, a bearing (36) located between the inner section and outer section, and seals (37,38) provided at either end of the fitting between the inner section and outer section. Pressure compensating means (39) are provided for maintaining the pressure within the bearing substantially the same as the external pressure. <IMAGE> |
