be reached by the water in the tub is described below such a feature applies for instance to the case of a washload made up of synthetic cotton fabrics where the water filled in to soak such fabrics while maintaining during the subsequent stabilizing cycles a significant pressure on the filter bell shaped trap for an appropriately long period of time quite to the contrary in the case of a washload made up by sponge cloth fabrics the same amount of water proves insufficient in view of ensuring a total soaking effect and therefore it is absorbed rapidly and entirely under an abrupt fall of the pressure below significant values in a relatively short time so that it proves impossible to record the new level in order to eliminate the drawback of the pressure switch not being able to directly measure the amount of water filled in it is necessary that the amount of water filled in be accurately measured regardless of the pressure head existing on the pressure switch this can be achieved by letting the water be filled in under time control once that the flow rate which depends substantially on both the water inlet means and the water delivery line pressure is known however for the actual flow rate to be known considering that it may vary due to a number of factors among which the water supply.