Protection of vacuum sensors in critical applications

Especially in harsh industrial environments vacuum metrology often has to cope with contamination such as oil and solvents making vacuum measurements a tough task.

Such contamination can impair measurement results as well as the related vacuum process and can even disable sensors. Vacuum gauges thus have to be readjusted, cleaned or exchanged after only short operating times.  Users can take some precautions in order to enhance the sensors life time despite demanding vacuum applications.  To this end, the use of robust gauges is a precondition. Thyracont Vacuum Instruments´ product range includes extra resilient sensors, which even withstand aggressive media. In addition, metal screens over the Pirani sensors provide extra protection against external influences.

Furthermore, the process is to be constructed in such a way that there is no direct line of sight between sensor and the source of contamination. For that purpose, a isolation valve which connects the vacuum gauges to a plant only when they are actually needed. This is simplified by two potential-free relay switch points which are standard for Smartline transducers with RS485 interface.

As a specialist for vacuum metrology, Thyracont also offers accessories for additional protection of sensors. In rough and fine vacuum, different components help to capture deposits, which can be caused for example by oil lubricated vacuum pumps. Angle pieces and spiral tubes have proved successful as vapours condense on their cooler metal surface with protective effect on the vacuum gauges.

Also seal rings with a fine wire filter can be used. They should be checked for contamination, cleaned or replaced as necessary in order to prevent the occurrence of a pressure gradient influencing the measurement values.

Thyracont developed a special metal baffle, which is constructed to prevent possible coating of the sensor to a large extent. It keeps oil molecules from getting into the vacuum chamber.

It is ideal for the use in fine and high vacuum and thus made for applications such as sputtering processes/PVD.

Special seal rings and baffles are particularly popular as cost-efficient solutions, as they do neither impact required space nor mounting position.

The correct use of the right vacuum gauges and corresponding protective measures contribute to a considerably enhanced operation life time, which in turn minimizes maintenance efforts and downtimes.