WIKA Diaphragm Seal with Threaded Connection (990.34)

Welded design


  • Aggressive, hot, corrosive, environmentally hazardous or toxic media
  • Oil and gas industry, chemical and petrochemical industries
  • Water treatment
  • Versatile in application

Special Features

  • Process connection with thread
  • Version with internal diaphragm, diaphragm seal parts fully welded
  • Large selection of process connections and materials
  • Flushing connections optionally available
  • High pressures up to 1,000 bar [14,500 psi] can be achieved

Sales Contact (Wika.sales@asyatrafo.com)




Diaphragm seals are used for the protection of pressure measuring instruments in applications with difficult media. In diaphragm seal systems, the diaphragm of the diaphragm seal effects the separation of the instrument and the medium.
The pressure is transmitted to the measuring instrument via the pressure transmission medium which is inside the diaphragm seal system.

For the implementation of demanding customer applications, there is a wide variety of designs, materials and pressure transmission mediums available.

For further technical information on diaphragm seals and diaphragm seal systems see IN 00.06 “Application, operating principle, designs”.

The diaphragm seal with threaded connection, model 990.34, is suitable for very versatile application areas. Depending on the material, the welded design can also be used for particularly high nominal pressures up to 1,000 bar [14,500 psi]. Another benefit of the welded joint is that no additional sealing between the upper and lower body of the diaphragm seal is needed.

Mounting of the diaphragm seal to the measuring instrument may be made via a direct connection, for high temperatures via a cooling element or via a flexible capillary.

For the material selection, WIKA offers a variety of solutions, in which the diaphragm seal can be made of different materials.