THE CALIBRATION OF A DIFFERENTIAL PRESSURE TRANSDUCER AT THE OPERATING PRESSURE WITH A PRESSURE AMPLIFIER

摘要

The measurement of the differential pressure is widely employed in the petrol industry for determining the flow rate, level, blockage of filters and the oil-water interface. The calibration of the differential pressure transmitters is usually made at atmospheric pressure, since there is little concern about the static pressure influence on the transducer performance. As a main contribution, this paper presents a calibration methodology of differential pressure transmitters. The ranges of the studied static pressure (from 0 to 20000 kPa) and differential pressure (from 40 to 250 kPa) cover Petrobras production and exploration operating conditions. To achieve the results, a pressure amplification device was developed and used at each port of the pressure transmitter. Thus, during the calibration of a pressure transmitter, the pressure differential at the transmitter ports is deduced from the measured value at nearly atmospheric pressure and the amplification factor. The uncertainty of the results was estimated and the methodology was used for the calibration of a pressure transmitter, showing that its calibrating curve varies with the operating pressure.