Method for operating a washing machine and washing machine

Abstract

In a method for operating a washing machine, a defined degree of wetting of items of laundry in the drum is required. This degree is brought about in determinable manner by alternately wetting the items of laundry in the drum from below and from above. At intervals, the items of laundry can be tumbled together or loosened up by rotation of the drum. The volume of water absorbed by the items of laundry can be determined by determining the total volume of water admitted into the washing machine and making a comparison with the volume of water not absorbed by the items of laundry. This absorbed water is assumed to be uniformly distributed within the items of laundry and a level of drenching or degree of wetting of the items of laundry can accordingly be determined. In this way, subsequent washing processes can be carried out in a more defined and overall better way.

1 . A method for operating a washing machine, wherein said washing machine has:
 a drum receptacle, in which a drum for accommodating items of laundry is arranged rotatably therein,   an injection device for introducing or injecting water from above into said drum,   a drive motor for said drum for rotation thereof,   a power supply for said drive motor,   a drain with a drain valve from said drum receptacle, wherein said drain is closable by way of said drain valve such that said drum receptacle can be filled with water at least in a lower region,   a water routing system with water lines, valves, a fresh water inlet into said washing machine, a waste water drain from said washing machine, a pump, said drum receptacle, said drain and said injection device,   a washing machine controller which is connected to said power supply for said drive motor and to said valves and said pump for driving them,   wherein the following steps are carried out:   A a dry weight of items of laundry in said drum is detected and a laundry/water ratio is specified,   B with said drain valve open, water is introduced via said fresh water inlet and from below through said drain into said drum receptacle and into said drum with said items of laundry therein, wherein a volume of water introduced via said fresh water inlet is detected or known, wherein, thereafter or during this process, said drum is rotated slowly or in a plurality of substeps,   C water is applied from above onto said items of laundry in said drum by way of said injection device, wherein said drain is closed by way of said drain valve and said drum is not rotated, wherein a volume of water introduced via said injection device is detected,   D said drum with said items of laundry therein is rotated by way of said drive motor at a speed of rotation of 70 rpm to 100 rpm such that items of laundry are also present in a region of an axis of rotation of said drum or exactly on said axis of rotation, wherein in said step D said drain valve is open and a presence of water and said volume of water draining away through said drain are detected,   E said drum is not rotated and, with said drain valve closed, water is applied from above onto said items of laundry by way of said injection device,   F procedure as in step D with rotation of said drum and opening of said drain valve in order to allow water to drain out of said drum receptacle through said drain, wherein said volume of water draining or drained through said drain is detected,   G a total volume of water in said drum and applied onto said items of laundry or said total volume of fresh water admitted into said washing machine and a volume of water drained through said drain are detected and compared in order to determine how much water has been absorbed by said items of laundry in said drum and, if said ratio of said volume of water to said weight of said items of laundry present in said drum does not yet correspond to said specified laundry/water ratio from step A, water is again applied from above onto said items of laundry by way of said injection device,   H if said ratio of said volume of water absorbed by said items of laundry in said drum to said weight of said items of laundry present in said drum corresponds to said specified laundry/water ratio from step A, a washing process for said items of laundry begins.   
     
     
         2 . The method as claimed in  claim 1 , wherein a quantity of additive required for a washing process is calculated on a basis of said volume of water known to be present in said washing machine and a known water absorption of said items of laundry. 
     
     
         3 . The method as claimed in  claim 2 , wherein said quantity of additive required for a washing process is calculated on said basis of said volume of water known to be present in said washing machine and said known water absorption of said items of laundry taking account of settings of a washing program set or selected for said washing process. 
     
     
         4 . The method as claimed in  claim 2 , wherein a point in time for addition of said additives during said washing process is adjusted, since said volume of water in said washing machine or in said drum and in said items of laundry present therein and said weight of said items of laundry are known. 
     
     
         5 . The method as claimed in  claim 1 , wherein, between individual steps B to H, said items of laundry are rearranged or tumbled in accordance with step B. 
     
     
         6 . The method as claimed in  claim 1 , wherein, in step B, fresh water is introduced into said drum receptacle, wherein said fresh water is admitted into said washing machine via said fresh water inlet. 
     
     
         7 . The method as claimed in  claim 1 , wherein, in step B, said introduced volume of water is set such that said weight of said items of laundry is twice to five times that of said weight of said introduced water as said specified laundry/water ratio corresponding to 2:1 to 5:1. 
     
     
         8 . The method as claimed in  claim 1 , wherein, in step B, water is permanently and uniformly introduced into said drum receptacle and said drum is permanently moved with a stop of at most 0.5 seconds to 5 seconds after each 10° to 45° rotation of said drum. 
     
     
         9 . The method as claimed in  claim 1 , wherein, after step B and before step C, said drum is rotated in an opposite direction to step B, wherein said drum is rotated slowly or in a plurality of substeps. 
     
     
         10 . The method as claimed in  claim 1 , characterized in that, in step C, water is introduced as fresh water from outside in addition to said water introduced in step B. 
     
     
         11 . The method as claimed in  claim 1 , wherein, in step D, a tunnel sensor device is used to detect whether items of laundry are present in a region of said axis of rotation of said drum or exactly on said axis of rotation. 
     
     
         12 . The method as claimed in  claim 11 , wherein said tunnel sensor device is configured to operate optically as a light barrier or reflection light barrier with a direction of illumination along said axis of rotation or parallel to said axis of rotation. 
     
     
         13 . The method as claimed in  claim 11 , characterized in that, in step D, said drum is rotated at a speed of rotation which is 5% to 50% below that speed of rotation at which a region of 3 cm around said axis of rotation of said drum is free of items of laundry. 
     
     
         14 . The method as claimed in  claim 13 , wherein said drum is rotated and said speed of rotation is increased until it is detected by way of said tunnel sensor device that a region of 3 cm around said axis of rotation of said drum is free of items of laundry and/or remains free of items of laundry for a period of at least 3 seconds to 10 seconds, and then said speed of rotation is reduced by 5% to 50%. 
     
     
         15 . The method as claimed in  claim 1 , wherein, in step D and/or in step F, said drain valve is opened and said volume of water draining away through said drain is determined, during which time no water is introduced into said drum or onto said items of laundry. 
     
     
         16 . The method as claimed in  claim 15 , wherein said volume of water flowing away through said drain is identified via a volume sensor, wherein said volume sensor is arranged on or in a filter downstream of said drain through which said water flows downstream of said drain. 
     
     
         17 . The method as claimed in  claim 16 , wherein said volume sensor is at least one filling level sensor. 
     
     
         18 . The method as claimed in  claim 1 , wherein, in step E, water present in said water routing system is first applied onto said items of laundry by way of said injection device and only once a laundry/water ratio specified according to step A is no longer maintained is water admitted to said fresh water inlet. 
     
     
         19 . The method as claimed in  claim 18 , wherein said applied water is drawn from said water routing system or from a reservoir arranged in said water routing system. 
     
     
         20 . The method as claimed in  claim 1 , wherein, in step G, water is freshly supplied via said fresh water inlet until said specified laundry/water ratio is achieved. 
     
     
         21 . The method as claimed in  claim 20 , wherein achievement of said specified laundry/water-ratio is monitored on a basis of monitoring said motor current of said drive motor with determination of said weight of said wet items of laundry in said drum. 
     
     
         22 . A washing machine for carrying out said method as claimed in  claim 1  which has:
 a drum receptacle, in which a drum for accommodating items of laundry is arranged rotatably therein, 
 an injection device for introducing water into said drum, 
 a drive motor for said drum for rotation thereof, 
 a power supply for said drive motor, 
 a drain with drain valve from said drum receptacle, wherein said drain is closable by way of said drain valve such that said drum receptacle can be filled with water at least in said lower region, 
 a water routing system with water lines, valves, a fresh water inlet into said washing machine, a waste water drain from said washing machine, a pump, said drum receptacle, said drain and said injection device, 
 a washing machine controller which is connected to said power supply for said drive motor and to said valves and pump for driving them and which is configured to carry out said method as claimed in  claim 1 . 
 
     
     
         23 . The washing machine as claimed in  claim 22 , wherein said water routing system has at least one filter which is arranged downstream of or below said drain. 
     
     
         24 . The washing machine as claimed in  claim 23 , wherein at least one filling level sensor is arranged in said filter.