Diaphragm seals

Industrial pressure measurement covers a very wide range of gas and liquid processes. The physical and chemical properties of these media sometime make them incompatible for contact with the sensing elements of pressure gauges or transmitters.

In such cases, the measuring instrument must be separated from the pressurized fluid by a system capable of transmitting the pressure to this instrument while isolating it from the fluid itself. This system is known as a diaphragm seal.

Diaphragm seals are used for the following applications:

• Corrosive fluids
• Fluids with high viscosity
• Fluids that solidify at ambient temperature
• Toxic fluids
• Hygienic applications in Food & Beverage and Pharmaceutical industry
• Very high or low process temperature

Baumer Technologies offers a wide range of diaphragm seals for nearly all applications and industries. Do not hesitate to contact our specialists to find the best solution for your applications.

Baumer Technologies diaphragm seals can be customized to match your application requirements. Select among a complete range of:

• Best possible adaptation of the instrument to the process conditions
• Extended life time of the instrument through protection from challenging process media
• Transmission fluids: -40° C to 400° C
• Wetted parts: Stainless steel, Hastelloy, Monel, Tantalum, Titanium…
• Coatings: PTFE, Gold
• Many standard process connections available (threaded, flanged, hygienic, specific)

A chemical seal consists of a diaphragm which is welded to a rigid upper part. The upper part is mounted (screwed or welded) to the connection of the instrument and the complete volume behind the diaphragm and inside the measuring system (e.g. the Bourdon tube) is evacuated and filled with a hydraulic transmission fluid. The pressure of the process medium which is in contact with the diaphragm is transmitted via the fluid to the sensing element of the instrument.

The seal can be mounted to the instrument directly, using a cooling tower or a remote capillary. Always the complete system will be filled with the transmission fluid. Several different transmission fluids are available to ensure best compatibility with the process conditions.

The complete system is designed in a way to guarantee a very high accuracy of the measurement and to minimize measuring errors caused by changes of the process or ambient temperature.