Patent ID: 7726115

Claim:
An axial flow positive displacement compressor comprising: an inlet axially spaced apart and upstream from an outlet, a compressor assembly including an inner body disposed within an outer body and the inner and outer bodies extending from the inlet to the outlet, the inner and outer bodies having offset inner and outer axes respectively, at least one of the inner and outer bodies being rotatable about a corresponding one of the inner and outer axes, the inner and outer bodies having intermeshed inner and outer helical blades wound about the inner and outer axes respectively, the inner and outer helical blades extending radially outwardly and inwardly respectively, the inner helical blades extending radially outwardly from an inner hub of the inner body, the compressor assembly having first and second sections in serial downstream flow relationship extending between the inlet and the outlet, the inner and outer helical blades having first and second twist slopes in the first and second sections respectively, and the first twist slopes being less than the second twist slopes.