Patent ID: 7708070
Filing Date: 2010-05-04
Classification: E21B,E21D,E21F

Abstract:
1. A shaft plug which is use is to be used to close a shaft, the shaft plug comprising a plurality of inflatable bladders, each bladder having an upper end and a lower end, the bladders being interconnected in an end to end relationship, the shaft plug further comprising a support which extends along the length of the shaft plug and around the shaft plug, said support comprising a set of cord elements located at angularly spaced intervals around the shaft plug, each cord element extending for the length of the shaft plug, each cord element fixed to the walls of the bladders at a plurality of positions spaced along the length of each bladder, the upper end of the cord elements being interconnected to enable the shaft plug to be supported from the upper end when the bladders are not fully inflated, each bladder having an inlet, a gas line connected to each inlet and intended in use to be connected to a source of pressurised gas to enable the bladders to be inflated, wherein in use each bladder is able to be inflated when in position in the shaft such that the inflated bladder will extend across the shaft to contact the walls of the shaft to be supported thereby and to consequently seal the shaft, said bladders being interconnected such that in use the uppermost bladder is positioned in the vicinity of the upper end of the shaft and the lowermost bladder is positioned in the vicinity of the lower end of the shaft, wherein each bladder when inflated provides support to a portion of the wall of the shaft in contact with the bladder.