Pressure Measurement – Diaphragm seals

Comprehensive diaphragm seal portfolio for all process applications

Diaphragm seals
  • Process temperatures up to +400 °C / +752 °F
  • Measuring range 0...400 bar / 0...5801 psi
  • Nominal sizes DN 15...125 / 1/2...5" in EN/ASME
  • Special materials, such as tantalum, titanium, hastelloy and highly vacuumproof PTFE sample
  • Very low temperature impact due to special membrane technology

 The OPTIBAR DS diaphragm seal series are used for pressure, density and level measurement, in particular for high process temperatures of up to +400 °C / +752 °F, for corrosive media, or in conjunction with different hygienic and pharmaceutical process connections. The form of the diaphragm seal (inline or membrane diaphragm seals) depends on the individual process requirements.

Diaphragm seals protect the pressure transmitter in order that its sensitive diaphragm does not come into direct contact with the process conditions. A diaphragm seal consists of a separating diaphragm, the process connection, the transfer pipe (e.g. capillary or cooling element) and the pressure transfer liquid. The process pressure acts on the separating diaphragm and is transferred to the membrane of the pressure transmitter via the transfer pipe. The liquid in the diaphragm seal is selected dependent on the application and the temperature range of use.

All OPTIBAR DS diaphragm seals can be individually manufactured from a suitable material according to the process conditions. The most difficult measuring tasks are also reliably achieved.


  • Membrane diaphragm seals for general applications in flange, cell and screw-in design
  • Membrane diaphragm seals for food/pharma/biotechnology; e.g. with Varivent, NEUMO BioControl and Tubus connections
  • Inline diaphragm seals for food/pharma/biotechnology, also in DN 10 and aseptic design
  • Hygienic surface roughness


  • Chemical
  • Petrochemical
  • Food and beverage
  • Pharmaceuticals
  • Biotechnology


  • Level measurement of aggressive, highly viscose, crystallising liquids
  • Level measurement at high process temperatures
  • Density and interface measurement of liquids in opened or closed containers