Types of Level Transmitter

Common types of level transmitters

1. Float-Type Level Transmitters 

• Working Principle: A float rises and falls with liquid level, moving a mechanical  arm or magnetic coupling that generates an output signal. 
• Applications: Water tanks, chemical storage, low-cost industrial applications. • Advantages: Simple, durable, easy to install. 
• Limitations: Not suitable for viscous, corrosive, or highly turbulent liquids. 

2. Capacitive Level Transmitters 

• Working Principle: Measures level by detecting changes in capacitance between  electrodes caused by liquid or solid materials. 
• Applications: Oil, fuel, chemicals, bulk solids in silos. 
• Advantages: No moving parts, can handle corrosive and viscous media. • Limitations: Sensitive to buildup on probes; requires calibration. 

3. Ultrasonic Level Transmitters 

• Working Principle: Emits ultrasonic waves; the time taken for the echo to return  from the liquid surface determines the level. 
• Applications: Water treatment, open channels, chemical tanks. 
• Advantages: Non-contact, easy to install, works for harsh liquids. • Limitations: Affected by foam, vapor, turbulence, or extreme temperatures. 

4. Radar (Microwave) Level Transmitters 

• Working Principle: Uses microwave signals reflected from the surface of the liquid  to determine the level. 
• Applications: Oil & gas, chemicals, cement silos, corrosive or high-temperature  liquids. 
• Advantages: Highly accurate, works in extreme conditions, non-contact. • Limitations: Expensive, requires expert installation. 

5. Differential Pressure (DP) Level Transmitters

• Working Principle: Measures pressure difference between the bottom and top of a  tank; this difference is proportional to liquid level. 
• Applications: Process industries, chemical tanks, high-pressure systems. • Advantages: Reliable, accurate in pressurized tanks. 
• Limitations: Requires maintenance; not ideal for sticky or slurry liquids. 

6. Optical Level Transmitters 

• Working Principle: Uses a light beam; when liquid crosses the sensor, light is  refracted, triggering a signal. 
• Applications: Small tanks, automotive, chemical dosing. 
• Advantages: Compact, precise for point-level detection. 
• Limitations: Limited range, opaque liquids may affect accuracy. 

7. Guided Wave Radar (GWR) Transmitters 

• Working Principle: Radar pulse is guided along a probe; the time of flight of the  reflected signal determines liquid level. 
• Applications: Chemical, oil & gas, pressurized or high-temperature tanks. • Advantages: Very accurate, works with foam, vapor, or solids. 
• Limitations: Expensive, probe can be damaged in solids.