MICRO-PROCESSOR CONTROL OF A MOVABLE SLIDE STOP AND A MOVABLE SLIDE VALVE IN A HELICAL SCREW ROTARY COMPRESSOR WITH AN ECONOMIZER INLET PORT

摘要

MICRO-PROCESSOR CONTROL OF A MOVABLE SLIDE STOPAND A MOVABLE SLIDE VALVE IN A HELICAL SCREW ROTARYCOMPRESSOR WITH AN ECONOMIZER INLET PORTABSTRACT OF THE DISCLOSUREA variable volume ratio screw compressor has a side loadinlet port for the injection of refrigerant vapor into theinterlobe volume. In order to improve efficiency,overcompression and undercompression are avoided by varying thelocation of the radial discharge port to give the compressor aninternal volume ratio matched to the pressure of the system inwhich the compressor operates. This is accomplished in thepresent application by locating a pressure sensing port noearlier than and preferably later in the compression than theside load injection port, but early enough in the compressionthat it will not communicate with the discharge port. Thepressure that is sensed in the sensing port is used to predictthe actual peak pressure in order that maximum efficiency may beobtained as a result of matching the internal volume ratio to thepressure ratio of the system.