| 摘要 |
PURPOSE:To perform a sensitive detection of a leakage spot, by a method wherein a given photo fiber, provided with a luminous source and a detector at an end, is mounted in the proximity of a housing partition for liquefied gas, and detects a reflection or damping of a light resulting from a minute bending of a fiber core wire due to gas leakage. CONSTITUTION:A photo fiber 3, provided with a fiber core wire 3a, and a resin coating layer 3b, whose expansion factor is larger than that of the core wire 3, is positioned in an insulating material 2 for a liquefied gas transportation pipe 1 and in the proximity of the pipe 1, and is used as a low-temperature sensor. If gas leaks at a position 1a on the pipe 1, a minute bent spot 3c is created at the fiber 3 due to a difference in sprinkage at low temperature between the core wire 3a and the coating layer 3b. The leakage post is reliably detected such that a photo pulse generating source and a detector are placed at one end of the fiber 3, a photo pulse is transmitted in a condition to release the other end, and a reflection wave PL1, which the other end reflects, and a wave PL2, which the leakage spot 3c reflects, are detected. |
