Verfahren zur Steuerung des Laugen-Abpumpvorgangs bei Waschmaschinen

The lye-pump feed is to be matched to the quantity of waste spinning water occurring. Appliances available on the market activate the lye pump over predetermined time profiles via the programme-switching unit. The "on" and "off" times of the lye pump are not always in synchronism with the quantity of waste spinning water occurring, so that the idling lye pump sucks in air and does not transport the lye away. By means of the solution according to the invention, the lye-pump feed is matched exactly to the quantity of waste water occurring and the spin run-up optimised. The laundry-drum drive motor is coupled to a tachogenerator. A speed breakdown in a laundry drum which is in the spin run-up mode serves as an indication of lye not transported away or of a lye pump sucking in air. The tachogenerator signal frequencies changing abruptly at the same time bring about, via electronics, an immediate brief switch-off of the lye pump for the self-venting of the latter. A subsequent lye feed can take place and the laundry drum can run up to its final spinning speed. The method is suitable for use in programme-controlled washing machines with a tachogenerator and with electronic speed regulation.