Turbine Testing With High-Line, Low Differential Pressure Measurement

The precise measurement of small pressure variations along and around the aerofoil stages of multi-stage machinery is error prone. This is attributable to high absolute pressures and low differential pressures. Using two high range transducers to measure pressure up and down stream of a stage, and calculating the differential by subtracting one from another introduces the error. This paper describes a method adapting low cost, low range differential pressure transducers to operate at line pressures above their burst pressure with improved accuracies. Multipoint and high-line zero calibrations, leak-checks and other troubleshooting configurations as well as a safe mode are possible.