There are fundamentally two ways to measure level of a fluid in a vessel, which are:
- Direct level measurement
- Inferential level measurement
Float, magnetostrictive, retracting, capacitance, radar, ultrasonic and laser level measurement falls under direct level measurement technique, whereas weight and differential pressure level measurement comes under inferential level measurement technology.
Differential pressure level sensors or Differential pressure transmitters are probably the most widely employed devices for the purpose of level detection. “Using DP for level is really an inferential measurement.
A DP is used to transmit the head pressure that the diaphragm senses due to the height of the material in the vessel multiplied by a density variable.”