Non-contact type fluid electric impedance measurement device and method based on digital phase sensitive demodulation virtual inductance technology

Abstract

The invention discloses a non-contact type fluid electric impedance measurement device and method based on a digital phase sensitive demodulation virtual inductance technology. The non-contact type fluid electric impedance measurement device comprises an insulating measurement pipeline, an excitation electrode, a detection electrode, a metal shielding cover, a virtual inductance module, a signal processing and communication module and a microcomputer. An alternating current excitation signal with specific frequency, which is generated by the signal processing and communication module, passes through the excitation electrode; under a series resonance state, inductive reactance generated by the virtual inductance module is used for eliminating influences which are caused by the fact that the electrode and fluid pass through an insulating pipeline to form capacitive reactance of a coupling capacitor, so that the total impedance of a detection circuit is equal to equivalent impedance of the fluid in the pipeline; then a detection signal is subjected to digital phase sensitive demodulation; and real part information and virtual part information of electric impedance of the fluid are acquired. The invention provides a feasible way for solving an electric impedance measurement problem of the fluid in the pipeline. The non-contact type fluid electric impedance measurement device and method have the advantages of simple structure of a sensor, non-invasion, adjustable inductance value, no influences on the flowing of the fluid in the pipeline and the like.

Description

technical field [0001] The invention relates to fluid electrical impedance measurement technology, in particular to a non-contact fluid electrical impedance measurement device and method based on digital phase-sensitive demodulation and virtual inductance technology. Background technique [0002] Fluids widely exist in industrial production and daily life, such as chemical industry, metallurgy, environmental protection, water quality monitoring, etc. Therefore, it is of great significance to measure the characteristic parameters of the fluid. Electrical impedance is a physical quantity used to measure the resistance to alternating current flowing in a circuit. Through the measurement of electrical impedance, not only the conductivity of the fluid can be known, but also other characteristic parameters of the fluid can be obtained, such as the concentration, composition, chemical reaction rate of the single-phase conductive fluid, and the phase holdup of the multi-phase fluid...

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Problems solved by technology

However, the inductance of the actual inductor used in this patent is difficult to adjust, and its own parameters such as distributed capacitance will also adversely affect the detection; in addition, the analog phase-sensitive demodulation technology used in this patent also has certain defects, such as: Calculation speed is slow, accuracy is poor, analog components are susceptible to temperature drift, etc.

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