Patent ID: 7896618

Claim:
A centrifugal compressing apparatus comprising: an impeller having a hub having a hub surface and an impeller blade extending along said hub surface, said impeller having an impeller flow entrance and an impeller flow exit, wherein a height of the impeller blade of said impeller is configured to decrease gradually from a front edge thereof to a rear edge thereof; and a casing configured to house the impeller, wherein the impeller blade has a shroud surface having a shroud line configured to oppose the casing, wherein the shroud line is configured to be convex at a rear edge of the impeller blade with respect to an intersection of a tangent drawn to the shroud line from a point P of an exit width L and the shroud line, wherein the point P is an intersection of said shroud line with said rear edge of said impeller blade, said rear edge having a length forming a flow exit width of said impeller, wherein said shroud line and point P are defined in a meridional surface.