Funktionale und energetische Optimierung von Vakuumpumpen

Vacuum systems are an essential part in industrial sectors like e.g. pharma-ceutical, food or chemical industry. Especially applications where high purity or the exclusion of ambient air is necessary, highly reliable negative pressure units are required. Depending on the specific process conditions, different types of vacuum pumps form the basis for vacuum generation. The diverse operating principles of these pumps all come with advantages and disadvantages in a variation of e.g. minimum vacuum pressure, volume flow, machine noise, sensitivity to humidity or dirt particles of gas the stream.

Liquid ring vacuum pumps and rotary vane vacuum pumps both perform with a high volume flow compared to machine size as a key feature. Against this the reachable vacuum quality and the relatively high operating noise limit their area of application. The main reasons for this is the unwanted gas input by the operation medium due to cavitation or gas solubility.

Hence, the aim of this thesis was to reduce the negative impact of these two types of vacuum pump to expand their operation limits. A screening of available technical fluids as a substitution was done and specimen from poly-alpha-olefins (PAO), ester and ionic liquids (ILs) were chosen from analytic point of view. A test rig for vacuum pumps was set up for the comparison of operating performance and noise emission.

For identification of local cavitation sources an optical accessible version of a liquid ring vacuum pump was investigated with a high-speed camera. For the first time, cavitation swirls inside this type of pump were visualized on high-speed footage.