990.41 Diaphragm Seal with Flange 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 by combining measuring instruments with diaphragm seals.

A system filled fluid inside can hydraulically transmit the pressure to the measuring instrument. This can be chosen to suit the particular application.

Almost limitless application possibilities exist due to the large number of available variants, such as 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.

The model L990.41 diaphragm seal with flange connection and internal diaphragm is ideally suited for applications with small process connections. Due to the internal diaphragm (large diaphragm diameter) low measuring ranges can be realised. When the temperature changes, the diaphragm counteracts the volume expansion of the system fill fluid, thus ensuring a lower deviation at the measuring instrument.


  • For assembly (direct assembly, via a cooling element or a capillary) with measuring instruments for low pressures and with differential pressure measuring instruments
  • For aggressive, contaminated or hot media
  • Chemical process industry, petrochemical industry
  • Level measurement, filter monitoring

Special Features

  • Internal diaphragm with large working volume
  • Special materials available
  • Low temperature error due to large diaphragm diameter (realisation of low measuring ranges possible)
  • Wide temperature application range due to large working volume
  • Integrated flushing connections (optional)


Application Datasheet – Fill Out and Return for Most Accurate Quote


Types of Media

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

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

For the material selection WIKA offers a variety of solutions, in which the upper housing, the diaphragm and the lower housing can be made of identical or different materials. The diaphragm and the lower body can also be offered coated or covered with foils.

Measuring systems with model L990.41 WIKA diaphragm seals are successfully used worldwide in the chemical process and petrochemical industries with high measuring requirements.