Small-aperture capacitive electromagnetic flow sensor

Abstract

The invention discloses a small-aperture capacitive electromagnetic flow sensor. The sensor comprises a shell, and a measuring guide pipe, a control device, an excitation circuit, an excitation coil,a signal electrode, a signal amplifier, a digital-to-analog converter and a power supply which are arranged in a cavity of the shell, wherein the excitation coil is arranged outside the measuring guide pipe, the excitation circuit is respectively connected with the excitation coil and the power supply, the measuring guide pipe is connected with the control device through the signal electrode, thesignal amplifier and the digital-to-analog converter. The sensor is advantaged in that the sensor belongs to a capacitive structure, the high-temperature co-fired multi-layer ceramic technology is creatively applied to the small-aperture measuring guide pipe, a capacitance value between a shielding layer and an electrode layer is stable and reliable, the induction capacitance value can be greatlyimproved, and compared with a capacitive measuring guide pipe with a conventional bonding electrode, the measuring guide pipe is higher in size precision, good in capacitance consistency, resistant tohigh temperature, resistant to vibration and resistant to corrosion.

Description

technical field [0001] The invention relates to the technical field of electromagnetic flow sensors, in particular to a small-aperture capacitive electromagnetic flow sensor. Background technique [0002] The electromagnetic flow sensor adopts Faraday's electromagnetic principle (Faraday's electromagnetic law formula E=kBLV). The liquid flows through the magnetic field, which is equivalent to treating the liquid as a conductor, cutting the magnetic field lines, and generating an induced electromotive force E. Among them, the induced electromotive force E is only related to the pipe diameter L and the magnetic field. Intensity B and flow velocity V are directly proportional. Since the parameters such as pipe diameter have been fixed as constants during design, the change of the induced electromotive force E is only related to the flow velocity V. By measuring the magnitude of the induced electromotive force E, the flow velocity V can be calculated, and further can be derived ...

AI Technical Summary

Problems solved by technology

The conventional capacitive electrode method is to spray electrodes on ceramics or other high dielectric constant materials, and shield them by attaching a metal shielding layer. The reliability is not high, the consistency is poor, and the thickness between the liquid and the liquid is greater than 1mm. Thickness and compactness are difficult to guarantee, poor weldability, and production consistency cannot be solved. The shielding layer is shielded by mesh metal, which requires manual bonding and poor reliability.

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