Screw Vacuum Pump: A rotary screw pump is amongst the earliest designed good displacement pumps which was often called the Archimedes‘ screw. In its most basic form, this pump consists of just one screw inside of a hollow cylinder. Modern types include double or triple screws meshing against each other. https://connerlvels.gynoblog.com/26574012/top-latest-five-vacuum-pump-urban-news