(under subclass 60) Apparatus in which the working fluid* flows along a path that is generally axial and contacts a plurality of blade* rows on said runners*, the rows having a common axis, the blades* of adjacent rows extending in opposite directions from their supports, the blades* of one row extending inwardly and the blades* of another row extending outwardly, at least one row of blades* extending into the spaces between the blades* of the two next adjacent rows extending in the opposite direction.
