Functional principle

The compression process of screw compressors takes place in one flow direction only. This special feature allows for an additional suction gas connection on the rotor housing.

The position of this ECO connection on the compressor is selected such that the suction process is already finished and a small increase in pressure has taken place.

• This allows a suction intake of an additional mass flow, thus increasing the overall mass flow on the high-pressure side, while maintaining it almost constant on the low-pressure side.
• In CSH65 .. 95, HS.85 and OS.85 screw compressors the ECO channel is integrated directly into the control slider (see figure below). This allows operation with a liquid subcooler independently of the load conditions of the compressor.
  Some other compressors can also be operated with ECO in certain capacity ranges, for details see:
• ST-430: Capacity control of BITZER screw compressors