Patent attributes
A laundry drying apparatus, in particular dryer or washing machine having drying function, has: a cabinet, a control unit (4) adapted to control a laundry drying cycle according to at least one drying program, a drum (18) rotatably arranged within the cabinet for receiving laundry to be dried, a drying air channel (20) adapted at least to guide drying air into the drum (18), and a heater unit (6) arranged at or in the drying air channel (20) and being adapted to heat the drying air. The heater unit (6) has two or more heating levels. A temperature sensor unit is adapted to detect the temperature of the drying air and to provide at least one temperature signal to the control unit (4). The control unit (4) is adapted to control the heater unit (6) to heat the drying air at a selected one of the two or more heating levels. The control unit (4) is adapted to select or determine and apply during the drying cycle one of two or more temperature threshold sets, wherein the two or more temperature threshold sets are used by the control unit (4) for determining the heating level to be applied by the heater unit (6) in dependency of the at least one temperature signal from the temperature sensor unit. The control unit (4) is adapted to select or determine one of the two or more temperature threshold sets in dependency of one or more operating parameters of the apparatus, wherein the temperature thresholds of the temperature threshold sets are mutually different or are not identical. During execution of the laundry drying cycle the control unit (4) is adapted to select or determine one of the two or more temperature threshold sets in dependency of one or more of the following operation parameters:a) the time or temporal progress of the laundry drying cycle,b) one or more operation parameters of or for the heater unit (6),c) an electrical or mechanical parameter of the drum (18) motor,d) a temporal gradient of the drying air temperature during execution of the laundry drying cycle, ande) an ambient temperature indicative for the temperature outside the apparatus cabinet or a temperature indicative of an apparatus component temperature.
