Petrodollars, portefljeomlgninger og den lange rente

A single-shaft multi-staged turbo compressor capable of compressing a gas at a large flow rate and with a high pressure ratio has a first impeller group composed of at least one oblique-flow impeller and a second impeller group composed of at least one centrifugal impeller. The impellers of the first and second groups are mounted on a common impeller shaft in a back-to-back relation.