The development and manufacture of atmospheric and vacuum furnace systems is a demanding task in terms of safety. High-temperature brazing, annealing, hardening, ageing and sintering give rise to particularly hazardous situations. Many special manufacturers therefore rely on safety pressure switches from WIKA.
In many applications, it is not only vacuum that is needed for the process. High pressure is very often used during heat treatment processes. Therefore, the pressure switch must be able to withstand full vacuum without changing its performance. In addition, the switch must operate under very low pressure (30 mbar and less) and at the same time be able to withstand a pressure of up to 15 bar.
The challenge in this application is to monitor the pressure in the furnace so that it can be reliably controlled, while at the same time preventing a door from being opened while there is still pressure in the furnace. Opening the door under pressure could, in the worst case, result in death, or at least serious injury. Because the potential danger is so high, SIL approval for the switch is required to achieve the safety rating.