Needle probe for analysis of multiphase flows

摘要

The probe has a light conductor (1) optically connected to an optical transmitter (9) and an optical receiver (10). A shield electrode (2) and a non-inverting input of a transimpedance amplifier (12) are connected to an alternate current (AC) voltage source (11), where the AC voltage is applied to the shield electrode. A differential amplifier (13) subtracts excitation voltage of the AC voltage source from output of the transimpedance amplifier such that the output of an impedance measuring branch is proportional to electrical conductivity of the medium to be detected.