CAPACITY CONTROL SYSTEMS FOR SCREW COMPRESSOR BASED WATER CHILLERS

摘要

078209-BWL CAPACITY CONTROL SYSTEMS FOR SCREW COMPRESSOR BASED WATER CHILLERS : A control system for a rotary helical screw compressor (10) of the variable speed type includes a variable speed motor driving (72) the compressor for varying the compressor capacity and a slide valve member (40) which is adjusted optimally for varying the volume of gas trapped in the working chamber prior to discharge as a function of the pressure ratio across the compressor. There is also provided a control system for a rotary helical screw compressor of the fixed speed type which include a first slide valve member for varying the compressor capacity through modulating the volume of gas trapped in the working chamber prior to compression and a second slide valve member for adjusting optimally the volume of gas trapped in the working chamber prior to discharge as a function of the pressure ratio across. the compressor.