Patent ID: 6926439
Filing Date: 2005-08-09
Classification: G01N

Abstract:
1. A fiber optical dew point hygrometer for determining dew point of a gas, comprising: a light emitter and a light detector optically coupled through a light path defined by at least one optic fiber, the path comprising at least one sensing gap; said gap is formed between the ends of two optic fibers, between the end of an optic fiber and the light emitter or between the end of an optic fiber and the light detector; at least one end of the optic fiber forming the sensing gap forms a dew forming surface in contact with said gas, whereby dew can form on said dew forming surface at said at least one end of the optic fiber, changing light transmitted from the light emitter through the gap to the light detector; temperature control device for controlling temperature of said dew forming surface and for controlling the temperature of the air adjacent to said surface; restoration means for essentially replacing said at least one end of the optic fiber on which dew can form, which can be impaired by solid deposits thereon during operation, by a new end of an optic fiber clean of solid deposits; and control mechanism for controlling operation of said temperature control device and for automatic activation of said restoration means after an operation phase of the hygrometer.