DISTRIBUTED FIBRE OPTIC SENSORS FOR THE DETECTION OF LIQUID SPILLS

A range of distributed fibre optic sensors for the detection and location of aqueous, chemical and hydrocarbon fluid spills is presented. The sensors incorporate polymers that convert the swelling into a localised loss on an optical fibre when fluid exposure occurs. Optical Time Domain Reflectometry (OTDR) techniques are employed to rapidly detect and locate target liquids and chemicals at multiple positions along the sensor length. Sensor exposure to fluid can typically be located within 30 seconds to an accuracy of 2 m over a total length of 10 km. Once the polymer has dried out, the sensor returns to a non-activated state where further spill events may be detected.

A brief description of the basic sensor construction and of the underlying technology utilised in its operation is given. Results from experimental tests of prototype sensors manufactured to detect water, humidity, hydrocarbon fuels and organic solvents are then discussed. The response characteristics of the sensors in a range of varying environmental conditions and their performance during practical field trials are outlined. We conclude with a summary of the important advantages of the sensor design and the range of applications where it can be effectively implemented.

Alistair MacLean, Walter Johnstone & Brian Culshaw
Optoelectronics Division

Chris Moran
Dept. of Pure & Applied Chemistry

Dan Marsh & Geoff Andrews
PINACL Communications, Kinmel Park
Bodelwyddan, Rhyl, Denbighshire, UK