Capacitance-based instrumentation for multi-interface level measurement

Abstract

An electrical capacitance method is described for the measurement of multi-interface levels of gas/liquid/solid, including the foam layer. It uses a novel multi-electrode capacitance sensing element. A capacitance transducer based on the charge/discharge principle is used, which is stray immune and capable of operating at high frequencies to reduce t h e effects of the liquid conductivity on the measurement. The presence of foam is detected by processing the fluctuating component of the capacitance signal, which reflects the inherently unstable feature of the foam, whereas t h e multi-interface levels are reconstructed by processing the steady-state component of the measured capacitances

On-line measurement of separation dynamics in primary gas/oil/water separators: Challenges and technical solutions—A review

“…Here, the measurement signals from each pair of capacitance sensors immersed in the layered system of phases generate a "capacitance profile" reflecting the actual distribution of phases in the vessel. Shi et al (1991) used a simpler approach, as shown in Fig. 12(b), in which an array of capacitance sensing electrodes was arranged on a single plate.…”

A planar capacitive precision gauge for liquid-level and leakage detection

“…Shi et al [2] presented a structure where electrode is removed and the capacitances are measured between the successive electrodes and . This method leads to a rather complex model to retrieve the level from the measured capacitances.…”

“…5) [4]. In this oscillator there is a linear relationship between the capacitance and the period (2) Using a multiplexer that is controlled by a microcontroller as has been suggested by Toth and Meijer [5], [6], the capacitances and can be selected independently. This results in the periods and , respectively.…”

Comparative study of printed capacitive sensors

“…Furthermore, this kind of devices can be manufactured without requiring micromachining but directly by using deposition of a layer on a substrate and, therefore, they are compatible with any kind of technology. Some authors have analysed the influence of geometry of this kind of structures in the sensor performance [5][6][7][8][9][10][11][12].…”