| 摘要 |
1,232,145. Wells &c. BYRON JACKSON Inc. 24 March, 1969 [16 April, 1968], No. 15402/69. Heading E1F. An apparatus for cementing underwater wells comprises a tubular cementing head H containing upper and lower cementing plugs 30, 40 having bores 31, 41 and each being releasable from supports 25 or 26 by fluid pressure when the bore is blocked by a device B2 or B1. In operation a deformable ball B1 pivot outwardly to release the plug 40 which descends in advance of the cement slurry through the bore 31 and blocks the bore 41. Increased fluid pressure behind the ball B1 breaks shear pins 26k and support arms 26f descends through the casing 12 until it abuts a seating 55. The deformable ball B1 is then forced through the passage 41 and drops into a cage C allowing the cement slurry to pass out through apertures 58'. A rigid ball B2 descends behind the cement slurry to block the bore 31 and releases the plug 30 which descends until it abuts the plug 40 (Fig. 6). An increase in fluid pressure behind the ball B2 signals that the cementing operation is complete. In a modification the ball B2 is replaced by a spear member Fig. 7, (not shown). |
