Patent ID: 8786867

Claim:
An inspection device for boiler furnace water wall tubes, which inspects reduced wall conditions of multiple water wall tubes extending in a vertical direction along inner wall surfaces of a boiler furnace and arranged adjacent to each other, comprising: a leg placed upright and fixed by a magnet onto a surface of a water wall tube; a support frame fixed to the leg to support a displacement sensor producing laser light to be irradiated onto the surface of the water wall tube; a moving mechanism for moving the displacement sensor in an axial direction of the water wall tube relative to the support frame; and a signal processing unit configured to calculate an amount of reduced wall thickness of the water wall tube from a difference between data of a surface shape of the water wall tube along a direction substantially perpendicular to the axial direction of the water wall tube obtained by the displacement sensor and data of a reference shape without reduction in wall thickness in order to evaluate a reduced wall thickness condition, the signal processing unit including a reference position calculating section for calculating a reference position for superposition between the data of the surface shape and data of the reference shape.