66.6 Closed Loop Dry Air Vacuum System6.7 Ambient Air Vacuum Conveying SystemMachine mount vacuum receiversMachine mount vacuum receiversMaterialselection deviceAmbient air passes throughvacuum purge valve andconveys material.QSM(Material selection station)Dry air passes through vacuum purgevalves and conveys material.CLR(Closed-loop relief valve)Closed-loop air fromvacuum pump exhaustDSV(Discharge selection valve)