/INS .The newly developed horizontal BITZER oil separator is ideal for use with ammonia screw compressors. Several separating stages can be combined in one vessel, making the system simpler and the units more compact. Thanks to multistep separation, the OAHC oil separators ensure minimal oil carry over rates well below 10 ppm. Optimized oil charge amounts and a service flange for simple filter replacement round off the benefits of the OAHC oil separator.