| 摘要 |
PURPOSE:To permit exact and quick detection of outbreak of a water infiltration accident and a position where the accident breaks out by winding an optical fiber on a cord-like water absorptive body made of a water swellable material which swells volumetrically when the body absorbs water, thereby constituting a titled sensor. CONSTITUTION:This sensor 1 for detecting water infiltration is optical fiber is constituted by winding the optical fiber 3 at a specified pitch on the rod- shaped water absorptive body 2 made of the water swellable material. The water absorptive body 2 swells and expands volumetrically by adsorbing water in the event of the water infiltration accident. Then, the size thereof increases and the volumetric expansion of the water absorptive body 2 acts as side pressures on the optical fiber 3, thereby generating bending such as microbending in the optical fiber 3. An increase in the loss of the transmitted light by this bending is detected by measuring the reflected light such as backward reflected light of the light entered into the fiber from the input end thereof. The outbreak of the water infiltration accident and the position where the accident breaks out are thereby quickly and exactly detected. |
