Turbomolecular pump system for gas separation

Gas mixturesare separated in a device (401) comprising a housing (403), a turbomolecular pump assembly (407) therein having inlet and outlet ends, a first chamber (409) adjacent the inlet end and having an inlet port (413) and a first outlet port (415), and a second chamber (411) adjacent the outlet end and having a second outlet port (417). Several devices (801, 803, 805, 807, 809 - see Fig 8) can be connected in series to provide a plurality of separation stages, each having a respective reference number n from 1 to N, inclusive The inlet port of a separation stage n is connected (821, 861) with the first outlet port of an adjacent stage n + 1, and the second outlet port of the stage n is connected (853, 857) with the inlet port of the stage n + 1. The inlet port of any stage may serve as a feed port. The first chamber of stage n = 1 and the second chamber of stage n = N have first and second product outlets (847 & 818), respectively.