Method and apparatus for washing in particular items of laundry

Abstract

A method and apparatus for washing items of laundry that makes provision to continuously filter the treatment liquid during the washing operation. As a result, interfering attendant materials in and on the treatment liquid are successively removed during the washing operation, which increases the efficacy of the washing operation. Provision is preferably made to remove both lighter constituents, such as foam and lint, from the treatment liquid and also to filter heavier constituents, such as impurities washed out of the items of laundry, from the treatment liquid using the same filter. The same filter can also be used, after the end of the washing operation, to filter the treatment liquid to be let out and to temporarily store the treatment liquid in a collecting tank before the filtered treatment liquid is reused. The invention thus permits multiple functions of the filter.

1 . A method for washing items of laundry, comprising:
 at least washing the items of laundry with a treatment liquid in a rotationally drivable drum ( 12 ),   removing the treatment liquid from the drum ( 12 ) as required by means of at least one outer drum ( 19 ) assigned at least to part of the drum ( 12 ), and   during at least the washing, the treatment liquid is filtered outside the drum ( 12 ) and the at least one outer drum ( 19 ).   
     
     
         2 . The method as claimed in  claim 1 , wherein the filtering is undertaken continuously during at least part of the duration of the washing process. 
     
     
         3 . The method as claimed in  claim 1 , wherein only some of the treatment liquid is continuously constantly circulated through a filter ( 22 ). 
     
     
         4 . The method as claimed in  claim 2 , wherein only some of the treatment liquid is continuously constantly circulated through a filter ( 22 ). 
     
     
         5 . The method as claimed in  claim 1 , further comprising continuously withdrawing an amount of treatment liquid from the respective outer drum ( 19 ) at at least one outflow ( 27 ,  28 ) and, after filtering, returning said treatment liquid again to the same outer drum ( 19 ). 
     
     
         6 . The method as claimed in  claim 1 , further comprising optionally or alternately filtering constituents which are lighter or heavier than the treatment liquid out of the treatment liquid. 
     
     
         7 . The method as claimed in  claim 1 , further comprising, in order to filter out lighter constituents from the treatment liquid, removing the treatment liquid, with the lighter constituents on the surface thereof, from the outer drum ( 19 ) and, in order to filter out heavier constituents of the treatment liquid, removing the treatment liquid, with the heavier constituents below the surface of the treatment liquid, from the outer drum ( 19 ). 
     
     
         8 . The method as claimed in  claim 1 , further comprising conducting treatment liquid to be let out of at least one outer drum ( 19 ) through or via the same filter ( 22 ). 
     
     
         9 . The method as claimed in  claim 1 , further comprising collecting the filtered treatment liquid by at least one collecting tank ( 31 ). 
     
     
         10 . The method as claimed in  claim 1 , further comprising filtering the treatment liquid by a filter ( 22 ) designed as a gravity filter. 
     
     
         11 . An apparatus for washing items of laundry, comprising:
 a rotationally drivable drum ( 12 ),   at least one stationary outer drum ( 19 ) which extends at least over part of the length of the drum ( 12 ), and   a circulating line ( 21 ) having at least one filter ( 22 ) is assigned to the at least one outer stationary drum ( 19 ).   
     
     
         12 . The apparatus as claimed in  claim 11 , further comprising a plurality of treatment liquid outflows ( 27 ,  28 ) assigned to the circulating line ( 21 ), wherein at least one of the plurality of treatment liquid outflows ( 27 ,  28 ) can be shut off. 
     
     
         13 . The apparatus as claimed in  claim 11 , further comprising an upper outflow arranged in the region of the surface ( 49 ) of the treatment liquid in the drum ( 12 ) and the outer drum ( 19 ) and another outflow ( 28 ) provided in the region of the bottom ( 20 ) of the respective outer drum ( 19 ). 
     
     
         14 . The apparatus as claimed in  claim 11 , further comprising at least one pump ( 24 ) provided in the circulating line ( 21 ) downstream of the at least one filter ( 22 ), as seen in the direction of flow of the treatment liquid through the circulating line ( 21 ). 
     
     
         15 . The apparatus as claimed in  claim 11 , further comprising an inlet ( 29 ), wherein the circulating line ( 21 ) is provided, downstream of the pump ( 24 ), with the inlet ( 29 ) which can be shut off and is for recycling the filtered treatment liquid into the same outer drum ( 19 ) from which the treatment liquid was removed for filtering. 
     
     
         16 . The apparatus as claimed in  claim 11 , further comprising a discharge line ( 21 ) on the circulating line ( 21 ), wherein at least one collecting tank ( 31 ) is assigned to the discharge line ( 21 ). 
     
     
         17 . The apparatus as claimed in  claim 11 , wherein the at least one filter ( 22 ) is a gravity filter. 
     
     
         18 . The apparatus as claimed in  claim 11 , wherein the drum ( 12 ) is an elongate cylindrical drum with a plurality of consecutive chambers ( 15 ), at least one of the chambers ( 15 ) being assigned an outer drum ( 19 ).