Patent ID: 7145649

Claim:
A method for detecting a leak in a liquid or air circulating system, comprising the steps of: applying a fluorescent material to the system in a manner to cause the material to leak from the system; activating at least one LED in a handheld housing having an open end through which the radiation emits radiation, a substantial portion of the wavelength of radiation emitted from the at least one LED falling within a range from 395 to 415 nanometers, different from the fluorescent leak detection dye absorption peak wavelength, and wherein substantially less radiation is emitted from the at least one LED in wavelengths above 415 nanometers than is emitted within the range from 395 to 415 nanometers; and shining the radiation transmitted from the at least one LED onto the system to excite leaked fluorescent material; and detecting a leak by the fluorescence of the leaked fluorescent material.