Patent ID: 8316931

Claim:
A system for launching cementing plugs in a subterranean well, wherein a bottom plug and a top plug are launched from a plug basket by means, comprising: i. a first portion, comprising a. the plug basket that initially contains the bottom plug and the top plug; b. a piston above the plug basket, initially connected to a main rod; c. a first movable rod inside the main rod; d. a first sleeve around the main rod within which a release mechanism is initially installed in a manner such that the main rod is securely attached to the piston; e. a second movable sleeve inside a tubular body that is positioned above the first sleeve under which a shear pin fixed to the tubular body prevents downward movement of the second movable sleeve; f. a third movable sleeve mounted at the top of the main rod, into which a first moveable rod protrudes; g. ports in the tubular body through which wellbore-service fluids may flow; and ii. a second portion, comprising a bottom dart having a second movable rod that initially extends from the top, but can be pushed down so that it extends from the bottom; and iii. a third portion, comprising a top dart.