The circuit of the control loop for controlling foam formation in aqueous solutions or dispersions is used particularly in textile finishing, dyeing and textile printing equipments. Its principle is based on an expedient connection of the correction elements in the signal path of the sensor for determining the speed of the flat product. An equipment with this circuit is suitable for the controlled application of textile auxiliary preparations or dyes to flat textile products (woven, knitted and fleece materials, warp thread systems etc.) or for the lamination of textiles and other materials.
