The invention relates to a tank for washing a warp thread, provided with a device for intensifying the washing effect set in rotation inside the tank. Each device includes a body having cylindrical geometry, having circular cross section, which has comprises a plurality of longitudinal bars arranged along the cylindrical side surface of the device. Between each pair of adjacent bars a longitudinal slit is defined. The body also has a pair of end elements extending radially, forming the opposite bases of the body and configured to support and enclose the bars. The body also has a pair of opposite rotation pins, obtained on the respective outer surfaces of the end elements and that extend along an axial direction and parallel to the direction of extension of the bars. The body also has a tangential turbodynamic flow generator, arranged inside the body and configured to intensify the interchange between the washing liquid and the warp thread through the longitudinal slits during the rotation of the device.
