electronic or mechanical type it should be noted that the cylinder 21 is rotatable about the arm 28 of the lever 23 via a pin 30 which enables it to adapt to the variation in inclination if transverse tension differences exist in the fabric 13 for example due to different tensions of the two selvedges or between one of the selvedges and an intermediate portion of the fabric 13 the elastic element 29 compresses as it is subjected to a greater thrust force determined by the tauter selvedge simultaneously by virtue of the arrangement of the invention the elastic element 29 provided at the other end of the penetrator roller 19 or 19a undergoes corresponding release this is because this second elastic element is subjected to a lesser thrust determined by the other less taut selvedge the axis of the roller 19 or 19a undergoes adequate inclination to the surface of the fabric 13 by virtue of the opposing movement of the two hubs 24 within the respective slots 26 in this manner treatment uniformity in the transverse direction of the fabric 13 is achieved about the wet treatment unit 12 there is also provided an outer second tank 31 for collecting fibrous textile material worn off the textile material 13 together with the water which entrains it the outer tank 31 comprises a bottom discharge 32 connected by an external circuit 33 to a filter and pump.