Abstract: An annular inner vane cover is axially spaced from a rotatably mounted runner and has first and second flanges. An annular water guide is disposed between said runner and said inner vane cover and has a third flange, which is jointed to said first flange. An inner tubular housing has a fourth flange, which is joined to said second flange. An annular runner cover surrounds said runner and has a fifth flange. An annular outer vane cover surrounds said inner vane cover and is radially spaced therefrom and has a sixth flange joined to said fifth flange, and a seventh flange. An outer tubular housing surrounds the inner tubular housing and is radially spaced therefrom and defines a welded interface with said outer vane cover. Outer and inner vane mounts are carried by said outer and inner vane covers, respectively. A plurality of vanes are provided, each of which is mounted for rotation on its own axis in one of said outer vane mounts and one of said inner vane mounts. Said flanges lie in parallel planes.