Examples of applications with diaphragm controllers

1) Regulation of a drying/distillatjon process, taking into account the maximum water vapor tolerance of a vane type rotary pump 

Mode of operation Starting from atmospheric pressure with the process heating switched off, valve V1 is initially open (maximum switching point exceeded) so that atmospheric pressure also prevails in the reference chamber. 

The diaphragm controller is therefore closed. When the system is started up, the connecting line between the vacuum pump and pump valve V2 is first evacuated. As soon as the pressure drops below the maximum switching point, valve V1 closes. When the pressure falls below the minimum switching point, valve V2 opens. 

In this manner the pressure in the reference chamber is slowly lowered, the throttling of the diaphragm controller is reduced accordingly and thus the process pressure is lowered until the quantity of process gas is greater than 

Depending on the quantity of vapor that accumulates, the throughput of the diaphragm controller is set by increasing or decreasing the reference pressure in each case so that the maximum permissible partial water vapor pressure at the inlet connection of the vacuum pump is never exceeded. 

---