plate 20 includes spirally formed fences or vanes 44 curling about the sharp ends of the blowing apertures 42 from origins in the hub portion 30 fig2 and 3 include an arrow to show direction of turning the vanes 44 are configured to catch air hence the blowing apertures 42 have a leading edge 46 and trailing edge and it is the trailing edge which was just previously characterized as the sharp end that is the vanes or fences 44 curl around the trailing edge of the blowing aperture 42 to thrust air forwardly with considerable force the plate 22 39 s web portion 34 ahead of the leading edge 46 is preferably flat or rather un featured to provide clearance for air the trailing edge is surrounded by the vane 44 curling around it in part the vane 44 catches the air that was given clearance ahead of the leading edge 46 fig3 or perhaps fig4 better shows that the vanes 44 are angled relative to the central axis in order to deflect or u201c force u201d air in the direction of the workpiece fig2 shows that the vanes 44 start at origins in the central hub 30 and thin as well as flatten out as the vanes curl or spiral out toward their terminations in the peripheral edge 32 in the lobe portions fig3 or again perhaps fig4 better shows that the vanes 44 form a cooperative funnel portion 48 for funneling caught air through the blowing aperture 42 39 s trailing end more general aspects of fig2 and 3 include the following the three other non blowing apertures which.