Capacitive Sensor For Water Level Measurement

Capacitance level sensors operate in the way that process fluids have dielectric constants significantly different to air.

Capacitive sensor for water level measurement.

5 v pp 3 khz ac signal is used as input signal for the system. The capacitive level measurement can be used in aggressive media when a fully coated probe e g. They measure the change in capacitance between two plates produced by changes in level. Applications tank level monitoring in chemical food water treatment power and brewery industries.

Capacitive level transducer is an example of indirect measurement of level capacitance level sensors are used for wide variety of solids aqueous and organic liquids and slurries. Also capacitive sensor is a noncontacting device in the common usage. Ultrasonic level sensors are used for non contact level sensing of highly viscous liquids as well as bulk solids. For d h 1.

It has typically high impedance sensor particularly at low frequencies as clear from the impedance reactance expression for a. An effective interdigital capacitive sensor for the water level measurement range of 0 30 cm with 0 2 cm resolution has been proposed designed and realized. ε r eff 1 ε r 2 from this equation the measured capacitive is proportional to the length submerged into water as the approximate capacitance per length of track for a coplanar sensor remains constant. Performing system calibration using labview software can help achieve higher accuracy.

They are also widely used in water treatment applications for pump control and open channel flow measurement. The sensors emit high frequency 20 khz to 200 khz acoustic waves that are reflected back to and detected by the emitting transducer. In this research water level sensor based on capacitive principal created using two copper plates with height h width b and distance l between two plates respectively 0 040 m 0 015 m and 0 010 m. A rod of stainless steel and a polytetrafluoroethylene ptfe insulated wire have been used for electrode of capacitive sensor.

There are two types of capacitive level sensor contact type or non contact type for water level measurement. Dielectric constant between two plates is proportional to water level. The technique is frequently referred as rf as radio frequency signals applied to the capacitance circuit. Capacitive sensor for water level detection has been fabricated.

The measurement principle is not affected by the density variation of the media. Experimental results confirm that the sensor described in this paper has high linear sensitivity good repeatability low cost low energy and simple installation. 1 have described the design and implementation of a liquid level measurement system based on a remote grounded capacitive sensor.