Rotary drilling equipment; Upper and lower Kelly cocks
Описание (англ.):
Lays down specifications for kelly cocks, i.e. manually operated valves in the circulating system of the drill stem, intended for use in blow-out emergencies, the upper cock being intended for use between the lower end of the swivel sub and the upper end of the kelly and the lower one for use between the lower end of the kelly and the upper end of the drill pipe or the upper end of the kelly saver sub. Describes: manufacture,required characteristics, test methods, marking and packaging.