Diaphragm seals. Versatile and robust.

Industrial pressure measurement covers a very wide range of gases and liquids. The physical and chemical properties of these products sometimes 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 e.g. for the following applications:

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

Bourdon 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 application.

Short delivery time thanks to stock availability of standard hygienic seals and all major components for threaded and flanged process connections.

Bourdon diaphragm seal can be custom made 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 from -60°C to 400°C
• Wetted parts: stainless steel, hastelloy, monel, tantalum, uranus, titanium, …
• Coatings: PTFE, Gold, Halar
• Many standard process connections of different industries available (threaded, flanged, hygienic, specific)

More choice, more variants. Find your product in the product selector.

A chemical seal consist of a flexible 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. 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 radiator 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.

The series D9xx is a line of diaphragm seals, which is especially optimized for use with electronic transmitters. The design of these seals and a very specific assembly and filling process make sure, that there is only a very small influence on the accuracy of process transmitters mounted.