for the delivery of substantial kinetic energy into the chamber intended to affect the substrate and or the fluid substrate interface referring to fig1 there is illustrated an agitator or impellor configured according to one embodiment of the present invention and which comprises of an externally mounted ac drive motor 10 connected to magnetic impellor coupler 12 and drive shaft 14 to which impeller 20 is attached and baffles 16 which are affixed to the interior of the pressure vessel cleaning chamber in about the same plane and just outboard of the impeller the impeller is positioned close to the surface of substrate 6 being cleaned in the wafer workpiece or substrate 6 gripping and rotatory embodiment the impeller 20 is replaced instead by a support mechanism for the substrate providing a rotating workpiece 6 it is understood by this that there would be no impeller and the workpiece would be mounted to the rotating assembly instead of the impeller it is further understood that the chamber may incorporate both a rotating workpiece mechanism and a mechanical agitator mechanism as by having one configured axially from above and the other configured axially from below with the prime side of the substrate or workpiece directed towards the agitator referring to fig8 and 9 in some embodiments a fluid operated rotary device 60 is used to rotate the workpiece in the processing chamber rather than an external motor coupled by a magnetic drive the assembly consists of wafer platform 62 with holes 64 for mounting wafer retention clips or other wafer or impellor holding structure to the underside of the wafer platform 62 there is attached the fluid bearing.