Abstract: A method of inspecting a heat exchanger for pressure resistance. The heat exchanger includes plural hollow refrigerant channel portions arranged in parallel and each having joints inside thereof, air passing clearances between respective adjacent pairs of refrigerant channel portions, and fins in the respective air passing clearances. The heat exchanger interior is pressurized, irradiated with light from one side, and a monochromatic image of the exchanger is captured by CCD cameras from the other side before and after the pressurization. Each image is divided into dots, luminance data of the dots of each image is converted into binary data items of white areas and black areas with reference to a threshold value, and the number of black areas is counted. The pressure resistance of the heat exchanger is judged based on an increase in the number of black areas after pressurization from the number of black areas before pressurization.

Abstract: A method of inspecting a heat exchanger for pressure resistance. The heat exchanger includes plural hollow refrigerant channel portions arranged in parallel and each having joints inside thereof, air passing clearances between respective adjacent pairs of refrigerant channel portions, and fins in the respective air passing clearances. The heat exchanger interior is pressurized, irradiated with light from one side, and a monochromatic image of the exchanger is captured by CCD cameras from the other side before and after the pressurization. Each image is divided into dots, luminance data of the dots of each image is converted into binary data items of white areas and black areas with reference to a threshold value, and the number of black areas is counted. The pressure resistance of the heat exchanger is judged based on an increase in the number of black areas after pressurization from the number of black areas before pressurization.

Abstract: A pair of reference portions 20 and 20 is brought into contact with an internal peripheral surface 11 of the vicinity of both side end portions of a tubular body 10. The tubular body 10 is rotated such that contact portions where the tubular body 10 and the pair of reference portions 20 and 20 contact move on the internal peripheral surface 11 in a circumferential direction of the tubular body 10 with positions of the pair of reference portions 20 and 20 fixed. The radial displacement of an external peripheral surface 12 of the tubular body 10 caused by the rotation of the tubular body 10 at at least one position 31 and 32 of an external side of the tubular element 10 is detected, wherein the at least one position is fixed relative to the circumferential direction of the tubular element 10.

Abstract: A pair of reference portions 20 and 20 is brought into contact with an internal peripheral surface 11 of the vicinity of both side end portions of a tubular body 10. The tubular body 10 is rotated such that contact portions where the tubular body 10 and the pair of reference portions 20 and 20 contact move on the internal peripheral surface 11 in a circumferential direction of the tubular body 10 with positions of the pair of reference portions 20 and 20 fixed. The radial displacement of an external peripheral surface 12 of the tubular body 10 caused by the rotation of the tubular body 10 at at least one position 31 and 32 of an external side of the tubular element 10 is detected, wherein the at least one position is fixed relative to the circumferential direction of the tubular element 10.