A hydrostatic level sensor is used to measure the head pressure created by liquid level. The greater the height of the liquid, the greater the pressure.

The sensor needs to be close to the bottom of the tank and either fitted on the outside via a thread or a flange, or submersed through the top of the tank and then fixed to the bottom.

The pressure creates movement of a flexible piece of metal or ceramic, known as a diaphragm. The position of the diaphragm is measured and a signal is produced that relates to the level of liquid in the tank.

As a hydrostatic sensor needs to be in contact with the product then we need to ensure that the materials are compatible, and any aggressive medium doesn’t eat away at the instrument. Most sensors are made from stainless steel which has good corrosion resistant properties, but for more aggressive fluids such as acids, the sensors can be made from alternative materials including plastics that will suit the conditions.