in a flow path of an overflow bend shown in fig2 and is of extremely flat configuration the backflow tank 10 is routed around a corner in front of a rear housing edge 11 on one hand to provide as much room as possible for its contents while on the other hand to occupy as little as possible of a vibrating area which is required by a vibrating tub unit in order to temporarily fix the line routing body 5 before the line connections are produced the line routing body 5 is provided with straps 12 and 13 which can be inserted through slits in the rear wall of the housing for retaining the line routing body 5 in such a way that it can move in the longitudinal direction of the lines the line routing body 5 which is illustrated specifically in fig2 contains the already mentioned riser pipe 6 and down pipe 8 as well as the backflow container 10 disposed in the path of the overflow bend 14 a detergent solution from the connecting tube 7 which solution is to be pumped away fills the backflow container 10 through a stub 15 and the riser pipe 6 before it passes through the overflow bend 14 and the down pipe 8 to the discharge hose 9 as soon as a pump pressure in the riser pipe 6 decreases atmospheric air flows out of the stub 16 into the overflow bend 14 and allows detergent solution columns to be discontinued this avoids a situation in which after the overflow bend 14 has been reached it is also possible for the tub to be emptied automatically by suction action when the pump.