Thermally sensitive product mixtures can be separated by means of the so called short path distillation. As the working pressure is decreased into the fine vacuum range this distillation is carried out at very low temperature.
By means of a wiper system the raw material to be processed is dispersed on a tube wall which is heated from the outside. Low-boiling components evaporate and are recollected at an internal condenser. The process pressure, which typically lies in the range 1e-3 mbar to 1 mbar, must be kept constant and recorded for quality assurance.
The vacuum display and control unit VD64P is used for monitoring and controlling process pressure. With isolated relay switchpoints a vacuum valve and, if necessary, a venting valve can be controlled. In combination with the included VSP63 Pirani transducer the required vacuum control can be realized in a reliable and cost-effective way. The serial USB interface of the VD6 is used for recording the pressure data during the whole process.
Source: VTA Verfahrenstechnische Anlagen GmbH