Patent ID: 7086353

Claim:
A lance system for inter-tube inspecting and lancing as well as barrel spraying of heat transfer tubes of a steam generator in a nuclear power plant, so that foreign substances piled up around heat transfer tubes of the steam generator are removed by spraying high-pressure water thereto, comprising: a rigid guide support rail positioned above a Blow Down Lane (BDL) at the center of the steam generator; a locomotion box including a motor drive unit for inducing a rectilinear motion of a lance body, and a motor drive unit for inducing a rotational motion of the lance body centering on a horizontal axis; the lance body including: a circular barrel including a motor drive unit for vertically erecting or horizontally laying down a multistage circular pole assembly, and a flat plate provided with linear passages for passing high-pressure water hoses, an optical cable and control rods therethrough; a circular drum assembly for stably connecting the high-pressure water hoses, the optical cable and the control rods to a nozzle block through the multistage circular pole assembly; and the multistage circular pole assembly being extensible and contractible by the movement of the control rods obtained by engaging teeth of a toothed belt unit, driven by a motor and positioned in the circular barrel, with gear teeth of the control rods; and two nozzle blocks, for barrel spraying, provided with barrel spray nozzles fixedly assembled therewith, symmetrically fixed to the inner surface of the circular barrel; wherein the multistage circular pole assembly is vertically erected in the operation of inter-tube lancing and inspecting, in which the lance system approaches inner parts of the heat transfer tubes and sprays the high-pressure water thereto, and is maintained in a horizontally laid-down position in the operation of barrel spraying.