Heat Exchanger for a Dryer, Especially for a Domestic Dryer

Abstract

A heat exchanger ( 1 ) for a dryer, especially for a domestic dryer, has a plurality of fins ( 2 ), wherein a flow channel ( 3 ) is established between two fins ( 2 ), and wherein air is guided along a flow direction (F) through the flow channel ( 3 ) from an inlet edge ( 4 ) to an outlet edge ( 5 ). To improve the behaviour of the heat exchanger as regards the collection of lint, at least the inlet edges ( 4 ) of the fins ( 2 ) have an at least partially rounded shape ( 6, 6′, 6 ″) seen in a direction perpendicular to the flow direction (F) and parallel to the surfaces ( 7 ) of the fins ( 2 ).

1 . A heat exchanger for a dryer, which has a plurality of fins, wherein a flow channel is established between two fins, wherein air is guided along a flow direction through the flow channel from an inlet edge to an outlet edge,
 characterized in that   at least the inlet edges of the plurality of fins have an at least partially rounded shape seen in a direction perpendicular to the flow direction and parallel to the surfaces of the fins.   
     
     
         2 . A heat exchanger according to  claim 1 , characterized in that the plurality of fins have a flat shape. 
     
     
         3 . A heat exchanger according to  claim 1 , characterized in that the rounded shape has a semi-circle shape. 
     
     
         4 . A heat exchanger according to  claim 1 , characterized in that the rounded shape connects the surfaces of the respective fin with a flat portion of the fin, wherein the flow direction is perpendicular to the flat portion. 
     
     
         5 . A heat exchanger according to  claim 4 , characterized in that the rounded shape has a quadrant shape. 
     
     
         6 . A heat exchanger according to  claim 5 , characterized in that the quadrant shape has a radius of 10% to 30% of the width of the fin at the inlet edge. 
     
     
         7 . A heat exchanger according to  claim 1 , characterized in that the rounded shape has a drop-shaped form. 
     
     
         8 . A heat exchanger according to  claim 7 , characterized in that the maximum width of the plurality of fins at the respective inlet edges measured in a direction perpendicular to the flow direction is greater than the width of the respective fins at a location in the flow direction behind the respective inlet edges. 
     
     
         9 . A heat exchanger according to  claim 1 , characterized in that the outlet edges of the plurality of fins have an at least partially a rounded shape seen in a direction perpendicular to the flow direction and parallel to the surfaces of the fins. 
     
     
         10 . A heat exchanger according to  claim 1 , characterized in that the surfaces of the plurality of fins are arranged at an acute angle to the flow direction. 
     
     
         11 . A heat exchanger according to  claim 10 , characterized in that the acute angle is between 0.25° and 2°. 
     
     
         12 . A heat exchanger according to  claim 10 , characterized in that the distance between the surfaces of the two fins decreases in the flow direction. 
     
     
         13 . A heat exchanger according to  claim 1 , characterized in that at least some of the fins of the heat exchanger are bent fins, wherein a bending at the inlet edges of the fins forms the at least partially rounded shape. 
     
     
         14 . A heat exchanger according to  claim 13 , characterized in that the bent fins comprise a draft angle between adjacent fins in order to have a decreasing distance between the surfaces of the adjacent fins in the flow direction. 
     
     
         15 . A laundry dryer comprising a rotatable drum for holding laundry to be dried, characterized in that the dryer comprises a heat exchanger according to  claim 1 . 
     
     
         16 . A laundry dryer according to  claim 15 , wherein said laundry dryer is a heat pump dryer.