of the cylinder 14 can be at a certain distance 17 above the superior face of the sheet 1 the tangential speed of the rotating cylinder 14 arrow 18 is independent of the forward speed of the sheet 1 or workpiece arrow 2 a nonwoven sheet 1 of 18 g m 2 obtained by the process called 34 wet process 34 is supported by a bronze linen of a knitted type comprising 32 threads in the chain sense and 27 threads in the weft sense this sheet is subject to the action of the apparatus represented in fig2 and 3 the perforated cylinder 14 presents orifices 16 of rectangular section of 0 8 mm in the axial sense arrow 19 and 1 3 mm in the tangential sense arrow 20 the distance between the orifices being 0 8 mm in both directions the cylinder 39 s 14 thickness is 0 4 mm and the orifice section is identical to the interior and the exterior of the cylinder the hydraulic injector comprises a perforated sheet 5 of 0 3 mm a thickness comprising 3 rows of holes of a diameter of 0 28 mm spaced from one point 6 mm from access to access following a generator and of 1 mm between the generators see fig3 the water pressure in the injector 3 is 3 5 bars chambers 4 and 12 the cylinder 14 is maintained at 0 5 mm above sheet 1 and its tangential speed of rotation arrow 18.