MICRO-PROCESSOR CONTROL OF COMPRESSION RATIO AT FULL LOAD IN A HELICAL SCREW ROTARY COMPRESSOR RESPONSIVE TO COMPRESSOR DRIVE MOTOR CURRENT

摘要

MICRO-PROCESSOR CONTROL OF COMPRESSION RATIO AT FULL LOADIN A HELICAL SCREW ROTARY COMPRESSOR RESPONSIVE TOCOMPRESSOR DRIVE MOTOR CURRENTAbstract of the DisclosureAn axial flow helical screw type compressor has a slidevalve member and slide stop member mounted end to end beneath theintermeshing rotors such that the slide valve member controlscommunication between the work chamber defined by the rotors andthe casing of the outlet port and the slide stop member and thevalve member together control the working fluid inlet to thebores of the rotors, the slide valve member and the slide stopbeing independently movable. Control means for the slide valvemember and slide stop include position sensing means for thesetwo members, inlet and outlet pressure sensing means, and meansfor feeding these inputs into programmable circuitry to controlthe positions of the slide member and slide stop. Additionalcontrol means senses the occurrence of full load operation andthen causes the slide valve member and slide stop member to moveas a closed unit in a given direction, or the reverse, as thecompressor drive motor current is sensed, continuously seekingthe position at which such current is at a minimum.- 1 -