How does a capacitive level sensor work?

- Aug 16, 2019-

According to the purpose and working principle, the liquid level sensor can be divided into a floating ball type water level sensor, a photoelectric water level sensor and a capacitive liquid level sensor. Both the float type liquid level sensor and the photoelectric liquid level sensor are contact type detection, and the capacitive water level sensor is non-contact type. How does the capacitive liquid level sensor work?


The capacitive non contact liquid level sensor uses a change in the liquid level to cause a change in capacitance. Based on the detected value of the capacitance, it is determined whether the position of the sensor is in a water state or a waterless state.


Capacitive is non-contact, so it only needs to be attached to the outer wall of the container for inspection. The reliability of each type of liquid level sensor is closely related to its working principle. What is the reliability of such a capacitive detection method?


The reliability of the c capacitive sensor is relatively high compared to the water level float switch affected by the water level. However, compared to optical levels of measurement, the reliability of a capacitive liquid level sensor is lower than optical level sensor.


The float type liquid level sensor is affected by the water level and is easy to be stuck. The reliability is extremely low, while the capacitive type does not. The photoelectric liquid level sensor is not affected by temperature, pressure, magnetic, corrosive and other factors. It is high and can be installed in multiple directions, so it can be applied to containers of any material. Capacitive type can only be used to detect liquids in non-metallic containers, because metal materials can also cause capacitive changes inside the sensor.


The biggest advantage of a capacitive liquid level sensor is non-contact detection, so even if the liquid is corrosive, it does not matter. Simply attach the capacitive liquid level sensor to the outer wall of the container and supply power to the sensor. The sensor can detect the change of the liquid level for a long time, and has the characteristics of low power consumption and convenient installation.