Abstract: Process and apparatus for reducing the liquid content of a porous material by means of superheated vapor from said liquid. The apparatus comprises, in order: a vapor generator 1; a circulation fan 2; a vapor superheater 6; a closed, sealed chamber 7, and an assembley 22-26 to provide in the chamber 7 a passage for fluid and for supporting textile material 9 such that it is interposed in the path of the vapor; a vapor condenser 13; a valve for regulation of pressure 16; a conduit for recycling vapor 17, and a device 32, 32a to measure the temperature prevailing in the fluid passage upstream of the porous material.