DETECTION OF FOREIGN MATTER IN INNER SURFACE OF OBJECT TO BE INSPECTED

摘要

PURPOSE:To enable detection of a foreign matter existing in contact with the inner surface of an object to be inspected as infrared image, by a method wherein the object being inspected is heated from the outer surface thereof, heating is stopped to deprive the object being inspected of heat with the fluidization of a fluid on the inner surface side thereof to be taken with an infrared camera on the outer surface thereof. CONSTITUTION:While an infrared camera head 3 of an infrared video device 2 is directed to the outer surface of a piping 1 as object to be inspected from one way, the piping 1 is heated almost evenly with a heater 7 in a range 6 of photographing the outer surface of the piping 1 held in a screen of a monitor TV and in the perimeter thereof. Then, the heating is stopped to take the outer surface of the piping 1 with the camera head 3 in the photographing range 6 heated. here, an internal fluid 9 flows through the piping 1 to deprive the piping 1 of heat from the inner surface side thereof. The piping 1 is deprived of heat by the fluid 9a passed from the inner surface side thereof at a portion 1b of the pipe wall with a foreign matter 8 in the inner surface less than at a portion 1a of the pipe wall without the foreign matter 8 thereon and appears as temperature difference on the outer surface of the pipe. This enables detection of the foreign matter 8 on the inner surface of the piping 1 as infrared image by photographing the outer surface of the piping 1 with the infrared camera head 3 immediately after the passage of the fluid.