The flow rate tramsmitter of the EVS 3000 series works in accordance with the turbine principle (recording the rpm of an impeller wheel rotating in the media flow). Depending on the version, additional connection openings for pressure and/or temperature transmitters are available.
The flow switches / flow rate transmitters of the HFS 2000 / HFT 2000 series are based on the variable area float principle.

  Electronic flow rate transmitters for general applications:

• EVS 3100 (for oils / viscous media)
  
• EVS 3110 (for water-based media)
• HFT 2100 (for oils / viscous media)
  

  Electromechanical flow switches for general applications:

• HFS 2100 (for oils / viscous media)
  
• HFS 2500 (for water-based media)
• HFS 250 (for water / water-based cooling lubricants)

Electronic flow rate transmitters for ex applications:

• HFT 3100 (flameproof enclosure)
• HFT 3110 (Intrinsically Safe)

Electromechanical flow switches for ex applications:

• HFS 2100 / HFS 2500  (Intrinsically Safe)