Plastic heat exchanger

Abstract

The invention relates to a plastic heat exchanger ( 1 ), in particular for automotive applications, having an inlet tank ( 2 ) which has an inlet ( 5 ) for a first fluid and surrounds an inlet chamber ( 6 ), having an outlet tank ( 3 ) which has an outlet ( 7 ) for the first fluid and surrounds an outlet chamber ( 8 ), having multiple plastic tubes ( 4 ) which are tightly connected to the inlet tank ( 2 ) and to the outlet tank ( 3 ) and connect the inlet chamber ( 6 ) to the outlet chamber ( 8 ) so they communicate with one another and around which a second fluid flows during operation. To improve the heat transfer, at least some of the plastic tubes ( 4 ) have at least one longitudinal section ( 9 ) in which ring-shaped areas ( 13 ) having variable cross sections follow one another in the longitudinal direction of the tube.

1 . A plastic heat exchanger, in particular for automotive applications,
 having an inlet tank ( 2 ) which has an inlet ( 5 ) for a first fluid and surrounds an inlet chamber ( 6 ),   having an outlet tank ( 3 ) which has an outlet ( 7 ) for the first fluid and surrounds an outlet chamber ( 8 ),   having multiple plastic tubes ( 4 ) which are tightly connected to the inlet tank ( 2 ) and to the outlet tank ( 3 ) and connect the inlet chamber ( 6 ) to the outlet chamber ( 8 ) so they communicate with one another and around which a second fluid flows during operation,   wherein at least some of the plastic tubes ( 4 ) each have at least one longitudinal section ( 9 ), in which ring-areas ( 13 ) having varying cross sections follow one another in the longitudinal direction of the tube.   
   
   
       2 . The plastic heat exchanger according to  claim 1 , wherein the respective longitudinal section ( 9 ) is designed in the manner of bellows or in the manner of a corrugated tube. 
   
   
       3 . The plastic heat exchanger according to  claim 1 , wherein the respective longitudinal section ( 9 ) is designed by forming the plastic tube ( 4 ) by upsetting during production of the plastic tube ( 4 ) in particular. 
   
   
       4 . The plastic heat exchanger according to  claim 1 , wherein the ring-shaped areas ( 13 ) have a corrugated profile or a sawtooth profile or a rectangular profile or a stepped profile or a combination thereof in the longitudinal direction of the tube. 
   
   
       5 . The plastic heat exchanger according to  claim 1 , wherein
 the ring-shaped areas ( 13 ) have ring bulges ( 15 ) all of which protrude inward or all of which protrude outward or one of which protrudes inward and the others of which protrude outward,   the ring bulges ( 15 ) connect tube areas ( 16 ) having constant or stepped cross sections to one another in the longitudinal direction of the tube.   
   
   
       6 . The plastic heat exchanger according to  claim 1 , wherein the plastic tubes ( 4 ) each have an inlet section ( 19 ) connected to the inlet tank ( 2 ), an outlet section ( 20 ) connected to the outlet tank ( 3 ) and a central section ( 21 ) connecting the inlet section ( 19 ) to the outlet section ( 20 ), the wall thickness ( 23 ) thereof being smaller than the wall thicknesses ( 24 ,  25 ) of the inlet section ( 19 ) and of the outlet section ( 20 ). 
   
   
       7 . The plastic heat exchanger according to  claim 6 , wherein the wall thickness ( 23 ) of the central section ( 21 ) is from 30% up to and including 70% of the wall thickness ( 24 ) of the inlet section ( 19 ) or the wall thickness ( 25 ) of the outlet section ( 20 ), such that the wall thickness ( 23 ) of the central section ( 21 ) amounts to in particular approx. 50% of the wall thickness ( 24 ) of the inlet section ( 19 ) or the wall thickness ( 25 ) of the outlet section ( 20 ). 
   
   
       8 . The plastic heat exchanger according to  claim 6 , wherein the reduced wall thickness ( 23 ) of the central section ( 21 ) is implemented exclusively by reducing the outside cross section ( 26 ) of the plastic tube ( 4 ). 
   
   
       9 . The plastic heat exchanger according to  claim 6 , wherein the reduced wall thickness ( 23 ) of the central section ( 21 ) is implemented exclusively by widening the inside cross section ( 27 ) of the outlet tube ( 4 ). 
   
   
       10 . The plastic heat exchanger according to  claim 6 , wherein the reduced wall thickness ( 23 ) of the central section ( 21 ) is implemented by reducing the outside cross section ( 26 ) of the plastic tube ( 4 ) and by widening the inside cross section ( 27 ) of the plastic tube ( 4 ). 
   
   
       11 . The plastic heat exchanger according to  claim 6 , wherein the respective longitudinal section ( 9 ) is situated in the inlet section ( 19 ). 
   
   
       12 . The plastic heat exchanger according to  claim 6 , wherein the respective longitudinal section ( 9 ) is situated in the outlet section ( 20 ). 
   
   
       13 . The plastic heat exchanger according to  claim 6 , wherein the respective longitudinal section ( 9 ) is situated in the central section ( 21 ). 
   
   
       14 . The plastic heat exchanger according to  claim 6 , wherein the respective longitudinal section ( 9 ) is situated at the transition ( 22 ) between the inlet section ( 19 ) and the central section ( 21 ). 
   
   
       15 . The plastic heat exchanger according to  claim 6 , wherein the respective longitudinal section ( 9 ) is situated at the transition ( 22 ) between the central section ( 21 ) and the outlet section ( 20 ). 
   
   
       16 . The plastic heat exchanger according to  claim 6 , wherein the respective longitudinal section ( 9 ) is situated in the central section ( 21 ) such that the central section ( 21  ) has a greater wall thickness ( 23 ′) in the area of the longitudinal section ( 9 ) than upstream or downstream thereof. 
   
   
       17 . The plastic heat exchanger according to  claim 6 , wherein the inlet section ( 19 ) comprises max. 20% or max. 10% of the total length ( 12 ) of the respective plastic tube ( 4 ). 
   
   
       18 . The plastic heat exchanger according to  claim 6 , wherein the outlet section ( 20 ) comprises max. 20% or max. 10% of the total length ( 12 ) of the respective plastic tube ( 4 ). 
   
   
       19 . The plastic heat exchanger according to  claim 1 , wherein at least two such longitudinal sections ( 9 ) are arranged in the respective plastic tube ( 4 ) with a distance between them in the longitudinal direction of the tube. 
   
   
       20 . The plastic heat exchanger according to  claim 19 , wherein the longitudinal sections ( 9 ) within the respective plastic tube ( 4 ) are a distance ( 28 ) apart from one another, said distance being at least five times greater than the inside diameter ( 30 ) of the plastic tube ( 4 ). 
   
   
       21 . The plastic heat exchanger according to  claim 1 , wherein the respective longitudinal section ( 9 ) extends from 5% up to and including 10% of the total length ( 12 ) of the respective plastic tube ( 4 ). 
   
   
       22 . The plastic heat exchanger according to  claim 1 , wherein the longitudinal sections ( 9 ) are arranged so they are offset relative to one another in the longitudinal direction of the tube in the case of neighboring plastic tubes ( 4 ). 
   
   
       23 . The plastic heat exchanger according to  claim 1 , wherein the inlet tank ( 2 ) is made of plastic and is welded to the plastic tubes ( 4 ). 
   
   
       24 . The plastic heat exchanger according to  claim 1 , wherein the outlet tank ( 3 ) is made of plastic and is welded to the plastic tubes ( 4 ).