AUTOMATIC MEASURING AND CALIBRATION UNIT FOR ELECTROCHEMICAL SENSORS

On line measurement of chemical parameters in multiphase flows under h igh pressure and high temperature by using electrochemical sensors req uires special devices for sensor positioning in the flow. These device s offer facilities for calibration, cleaning or replacement of sensor without pressure reduction or flow interruption. A new kind of automat ic measuring and calibration unit with four different sensors for meas urement in pipe flows is introduced. Miniature hydraulics ensure fast reliable sensor insulation from the pipe flow in order to calibrate or replace sensors. The unit was tested successfully at pressure up to 2 .5 MPa and at temperatures up to 110 degrees C. Sensor response during calibration and sensor stability in aggressive two-phase flows were i nvestigated. The construction is easily adaptable to different sensors and pipe diameters and suitable for a variety of pipe and sealing mat erials.