990.18 990.19 990.20 990.21 Diaphragm Seal with Sterile Connection

A diaphragm made of the appropriate material provides for the separation from the medium to be measured. This allows for even the most difficult measuring requirements to be met. This is done by combining measuring instruments with diaphragm seals.

A fluid inside the system is hydraulically transmits the pressure to the measuring instrument. This fluid can be chosen to suit the particular applications.

Almost limitless application possibilities exist due to the large number of available variants. For example, diaphragm seal designs or materials. The type of process connection (flange, threaded and sterile connection) and the basic method of manufacture are important design differentiation criteria.


  • Food and beverage production
  • Breweries
  • Soft drink production
  • For dairies, dairy products

Special Features

  • For cleaning easy to remove
  • Quick cleaning of measuring point, without residue
  • Suitable for cleaning out of place (COP)
  • 3-A compliant


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Types of Media

  • Aggressive media
  • Adhesive media
  • Crystallising media
  • Corrosive media
  • Highly viscous media
  • Environmentally hazardous media
  • Toxic media

The model L990.18 diaphragm seals with threaded connection are particularly suited for use in the food industry. The process connection enables a hygienic integration into the process. The diaphragm seal systems can withstand the cleaning vapour temperatures occurring in the SIP processes. This ensures a sterile connection between the medium to be measured and the diaphragm seal.

Assembly of the diaphragm seal and measuring instrument is made via a direct assembly as standard. Optionally via a cooling element or a flexible capillary.

Stainless steel 316L (1.4435) is used as standard material. Other special materials are available on request.

Measuring systems with the WIKA model L990.18 diaphragm seals are used for pressure measurement in various process steps. For example: filtration, separation, pasteurisers, and filling systems.