| 摘要 |
PURPOSE:To make high water stoppability securable irrespective of form in a level drilling pipe by attaching a ring brush, made up of laminating metallic fibers, to a ring casing inner circumferential surface, applying a flexible patch to the outer surface, and charging grease into a space part. CONSTITUTION:Ring brushes 16 made up of laminating metallic fibers are attached to an inner circumferential surface of a ring casing 12 at intervals. Flexible patches 18 covering at least an outer surface part of these ring brushes 16 are attached to the ring casing 12 after being lapped with each other. In addition, a wave resistant water stop agent of fiber-mixed greaser 20, 20 or the like is filled up in a space part between these ring brushes 16. |
