Patent ID: 8235678
Filing Date: 2012-08-07
Classification: F04D,H01J

Abstract:
1. A pumping arrangement for differentially pumping a plurality of chambers comprising: a compound pump having a first inlet for receiving fluid from a first chamber; a second inlet fir receiving fluid from a second chamber; a third inlet for receiving fluid from a third chamber, a fourth inlet for receiving fluid from a fourth chamber; a first pumping section; a second pumping section downstream from the first pumping section; a third pumping section downstream from the second pumping section and wherein the first, second, and third pumping sections being arranged such that fluid entering the compound pump from the first inlet passes through the first second, and third pumping sections, fluid entering the compound pump from the second inlet passes through, of said sections, only the second and third pumping sections, and fluid entering the compound pump from the third and fourth inlets passes through, of said sections, only the third pumping section; a booster pump having a first inlet for receiving fluid from the forth chamber in parallel with the fourth inlet of the compound pump; a backing pump having an inlet for receiving fluid exhaust from the booster pump; and means for conveying fluid from the pumping sections of the compound pump to the backing pump.