A Displacer Level Transmitter is a type of level measurement device that works based on buoyancy principles. It uses a displacer (a cylindrical or rod-shaped object) suspended in the liquid, and as the liquid level changes, the apparent weight of the displacer changes, which is converted into a level measurement.
Working Principle:
- A displacer is suspended in the liquid inside a chamber or directly in the tank.
- As the liquid level rises, the displacer experiences a buoyant force, reducing its effective weight.
- A torque tube or spring mechanism detects the change in weight and converts it into an electrical signal.
- The signal is processed by the transmitter and sent as a 4-20mA or digital output (HART, Foundation Fieldbus, etc.) to the control system.
Key Features & Advantages:
- Can measure both liquid level and interface level in multi-phase liquids.
- Suitable for dirty, viscous, or corrosive fluids when used with proper materials.
- They are ideal for high-pressure, high-temperature, and challenging process conditions
Common Applications:
✅ Oil & Gas – Measures liquid levels in separators and storage tanks.
✅ Chemical Processing – Used for aggressive chemicals.
✅ Power Plants – Monitors boiler drum levels.
✅ Refineries & Petrochemicals – Measures interface between oil and water.