Different Types of Level Sensors and their Workings

Industrial applications include liquid-level sensing in transport tanks, storage tanks and water treatment tanks, and also in the petrochemical industries for sensing liquids such as petrol, diesel and other fuels. Liquid level measurement is significant in household applications including electronic devices such as, water dispensers, water evaporators, steamers, monitoring system of boilers, heating systems, washing machines, steam irons, juice squeezers, automated-coffee machines, etc. Level sensors are designed for specific applications compared to general applications.

Classification of Level Sensor Measuring Systems
The family of level Sensor measurement systems is classified into different categories such as:

Liquids or Solids Level Measurement
Point or Continuous Level Measurement
Electromagnetic or Electromechanical Level Measurement
Contacting or Non-Contacting Level Measurement
General Considerations for Liquid Level Sensor Selection:
Density and viscosity
Vapors mist and dust
Chemical composition
Interfaces and gradients
Ambient temperature
Humidity/moisture
Process temperature
Process pressure
Regulated environment
Out of these four types of measurement systems, this article describes about the point level measurement and detection system, and the Continuous Level Measurement and Detection Systems are explained briefly in the following paragraphs. These both measurement systems cover different types of level sensors.

Point/ Liquid Level Switch Measurement and Detection Systems
Point level measurement sensors are used for the purpose of marking a single liquid height or for presetting a level condition. Usually, this sensor works as a high alarm that measures the overflow conditions in tanks through liquid level sensors, or works as a marker to note down the low alarm conditions. The different types of sensors are given below:

Float Sensor
Capacitance Sensors
Conductivity Probes