the same diameter which are driven with the same superficial speed than the travelling speed of the web 20 the axes of the rollers lie in a vertical plane the upper roller 32 is stationary whereas the lower roller 34 having a rubber surface coating may be raised and lowered by the pneumatic hydraulic or electric motor 36 the two rollers may also be interchanged a liquor sensor 40 is provided within the free space in front of the nip 41 of the rollers 32 34 and laterally from the web 20 the sensor is designed to detect liquor portions which may be temporarily squeezed out of the web and which will be present as tiny bulbs the liquor sensor 40 may be constructed in any known manner it may for example sense the liquid level by surface contact or it may operate based on electrical magneto electrical hall effect or reflectory parameters such as light from an infrared or a laser source other radiations such as beta or gamma radiations soft x rays corpuscular radiation etc the sensor 40 is preferably adapted to sense or scan periodically over the width of the web 20 for example with a scanning frequency of some hertz it is only essential that the sensor 40 supplies a signal representative of a true information about the presence or absence of liquor at any location in front of the roller nip 41 the web 20 now is conducted into the drier 46 and is finally wound up on the roll 16 instead of a real physical material web 20 rows of parallel yarns forming one or more horizontal layers for example warp yarn layers may also be used and treated the device comprises furthermore control and.