Fiber optic sensors for the refinery of the future

Abstract

We are manufacturing fiber optic sensor/transducers for the measurement of temperature, pressure, differential pressure, strain, vibration, acceleration and acoustic emission. The major technical advantages of our instrumentation are the small size, the inherent safety, immunity to EMI, and tolerance to high temperatures. Each transducer unit contains the same fundamental fiber optic sensor - a Fabry-Perot displacement sensor. For each individual measurement parameter such as temperature or pressure the transducer is designed and packaged such that the transduction mechanism results in a displacement that is measured by the fiber optic sensor. The packages look similar to commercial transducers that use electronic sensors such as strain gages or piezoelectric crystals, Since our transducers all contain the same type of sensor, the signal conditioners are identical and as a result, we achieve significant benefits including increased reliability, reduced cost and capability to provide a single multiplexed system that can accept inputs from any type of transducer. In this paper, we discuss the Fabry-Perot sensing mechanism and the operation of the optical signal conditioner and readout electronics. We describe the results of an extensive characterization program performed on temperature and pressure transducers. We also discuss the multiplexing approach and communications options. Finally, we discuss other refinery measurement needs and transducers we are developing to make the measurements.