40 sec tube 14 inlet pressure p4 0 30 psig 0 30 psig 0 30 psig mpsd 16 processing time in lt 15 sec lt 15 sec lt 15 sec mpsd 16 pressure p5 30 60 psig 75 95 psig 75 95 psig expansion volume 22 refiner feeder 30 and casing 28 dwell time in lt 10 sec lt 10 sec lt 10 sec expansion volume 22 refiner feeder 30 and casing 28 fig2 a and b are schematics of a macerating pressurized screw 16 with dilution injection feature suitable for use with the present invention according to the embodiment of fig2 a chip material 32 is shown in the central dewatering portion of working section 20 where the diameters of the perforated tubular wall 34 rotatable coaxial shaft 36 and flights 38 are constant a chip plug 40 is formed in the plug portion of the working section immediately following the dewatering portion where the wall is imperforate and the shaft has no flights but the shaft diameter increases substantially producing a narrowed flow cross section and thus a high back pressure that enhances the extrusion of liquid from the chips through the drain holes formed in the wall of the central portion the constricted flow and macerating effect may be further enhanced or adjusted by use of a tubular constriction insert not shown within.