| 摘要 |
PURPOSE:To determine the period of change of ultraviolet lamps precisely by monitoring the change of the amount of light of the ultraviolet lamp by a photodetector consisting of an interference filter and a photoelectric conversion element. CONSTITUTION:Beams 3, 4 having wavelengths of 185nm and 254nm projected from an ultraviolet lamp 2 positioned in an ultraviolet washer 1 decompose and remove organic contaminants 6 adhering on the surfaces of bodies to be washed 5. Beams 7 having a wavelength of 313nm projected from the ultraviolet lamp 2 are detected by a detector 8, and the change of the intensity of light is monitored continuously. When the intensity of light reaches a set value or less, the ultraviolet lamp in replaced with new one. Accordingly, the lifetime of the ultraviolet lamp can be detected accurately, thus projecting stable ultraviolet rays at all times, then stabilizing washing capacity. |
