Paper press roll assemblies

Claim 1

A GENERALLY CYLINDRICAL APRESS ROLL SHELL ADAPTED TO BE MOUNTED FOR ROTATION ABOUT ITS CENTROIDAL AXIS AND TO PRESENT TO A LPRESSURE NIP A PERIPHERAL ROTARY SURFACE PORTION, SAID SURFACE PORTION HAVING ALTERNATING GENERALLY CIRCUMFERENTIALLY ALIGNED GROOVES AND RIDGES, SAID GROOVES HAVING AN AXIAL DIMENSION AT THE ROLL PERIPHERY OF 0.005 TO 0.035 INCH AND EXTENDING RADIALLY INWARDLY TO IMPART TO THE CROSS SECTIONAL AREA OF EACH SAID GROOVE A VALUE SUBSTANTIALLY EQUAL TO AT LEAST TWICE THE SQUARE OF SAID GROOVE AXIAL DIMENSION, SAID RIDGES EACH PRESENTING A GENERALLY CYLINDRICAL OUTER PERIPHERAL LAND AREA HAVING AN AXIAL DIMENSION OF 0.05 TO 0.25 INCH THAT IS SUBSTANTIALLY 2 TO 20 TIMES SAID AXIAL GROOVE DIMENSION, AS AN AVERAGE ALONG AN AXIAL LNE ON THE ROLL PERIPHERY, THEREBY PRESENTING A ROTARY SURFACE PORTION WITH AN AVERAGE EFFECTIVE OPEN AREA OF NOT MORE THAN SUBSTANTIALLY 33 1/3%.