Method for controlling drying processes in household washer-dryers

Abstract

Household washer-dryers include a laundry drum having an incoming air inlet and a waste air outlet, a blower in an air conduit, a heating device upstream of the air inlet, temperature and moisture sensors, a memory for measured values and process sequence variants and an electronic program control unit. A method for controlling drying processes in such devices includes measuring a waste air temperature at the air outlet at a starting point of a drying process. At least part of the heating device is periodically turned on and off during at least one time segment at a beginning of the drying process. Air temperature measurements are taken at an inlet of the heating device, upstream of the air inlet and immediately downstream of the air outlet, after an expiration of a starting phase having a duration being dimensioned in terms of a length of one to three heating periods, and differences from the measured values in the waste air, at the inlet to the heating device, and in the incoming air are formed and stored in memory. Process variables are measured at least periodically at frequencies of several times per second, and a plurality of memorized process sequences are called up to the memory each time for output to and processing in the program control unit, upon attainment of predetermined threshold values as a function of entered program parameters pertaining to type, amount and/or initial residual moisture of laundry.