Patent ID: 10514290

Abstract:
A capacitance measuring apparatus and method detects gas/liquid and liquid/gas transitions by monitoring a sensing capacitor having a gap in fluid communication with a monitored volume. The capacitor electrodes can be any arrangement that does not obstruct drainage, such as parallel plates or concentric cylinders. Embodiments have smooth and/or low wetting surfaces. Detection thresholds are automatically set to account for remnant drops and coatings of liquid, and can be automatically readjusted if additional liquid drains or a different liquid is introduced. Embodiments include an insulating layer to prevent conduction through a conductive liquid. A second capacitor can be included in series and/or the insulating layer can create a second virtual capacitor in series with the sensing capacitor gap to provide high sensitivity at low capacitance. The sensing capacitor can be combined in a cluster with a pressure sensor and/or temperature sensor.