Distributed fiber-optic sensor with substance selective permeable coating

DETAILED DESCRIPTION A leakage monitoring system for above-ground and below-ground storage tanks utilizes fiber optic technology.
The monitoring system has a sensor which consists of an optical fiber coated with a special membrane that is selectively reactive with a specific substance.
These fibers can be run for extended lengths in, around and under storage tanks in such as a tank farm.
A centrally located optical generation and detection station provides source light through the optical fiber along with a detector for detecting changes in a light field within the optical network, which changes are susceptible of scaler evaluation, and a read out to provide leakage notice, alarm, etc.
The present invention discloses two separate embodiments, first, a differential absorption system and second, a long path absorption system.