Inner fin and flat tube including an inner fin

Abstract

An inner rib, in particular for a flat tube, in particular of a heat exchanger, made from a metallic flat strip, which is shaped in a wavy modulated manner, having a large number of wave crests and wave troughs, which are each arranged alternately in a longitudinal direction of the inner fin, an essentially straight, web-like fin area being provided between one wave crest and an adjacent wave trough and connecting the wave crest to the wave trough, the metallic flat strip having a first strip thickness L1, which is essentially constant in the area of the wave crests and the wave troughs, the flat metallic strip having a second strip thickness L2, which is provided in the area of the web-like fin area, L2 being smaller than L1.

What is claimed is: 
     
         1 . An inner fin for a flat tube of a heat exchanger comprising:
 a metallic flat strip formed in a wavy modulated manner;   a plurality of wave crests and wave troughs formed in the metallic flat strip, the plurality of wave crests and wave troughts being arranged alternately in a longitudinal direction of the inner fin; and   an essentially straight, web-like fin area formed between one wave crest and an adjacent wave trough, the web-like fin area connecting a wave crest to a wave trough,   wherein the metallic flat strip has a first strip thickness L 1 , which is essentially constant in an area of the wave crests and the wave troughs,   wherein the flat metallic strip has a second strip thickness L 2 , which is formed in the area of the web-like fin area, and   wherein L 2  is smaller than L 1 .   
     
     
         2 . The inner fin according to  claim 1 , wherein the metallic flat strip has a first strip thickness L 1 , which is essentially constant in the entire area of the wave crests and the wave troughs, and wherein the flat metallic strip has a second strip thickness, which is essentially formed in the entire area of the web-like fin area. 
     
     
         3 . The inner fin according to  claim 1 , wherein the metallic flat strip is curved in the area of the wave crests and the wave troughs. 
     
     
         4 . The inner fin according to  claim 1 , wherein the strip thickness reduction R from the first strip thickness L 1  to the second strip thickness L 2  takes place in a range from 0.2*L 1  to 0.9*L 1 , i.e. 0.2*L 1 <L 2 <0.9*L 1 , in particular 0.3*L 1 <L 2 <0.7*L 1  or further in particular 0.35*L 1 <L 2 <0.55*L 1  or further in particular L 2 =0.5*L 1 . 
     
     
         5 . The inner fin according to  claim 1 , wherein the metallic flat strip has two oppositely situated wide sides, between which the strip thickness is determined, the strip thickness reduction R from the first strip thickness L 1  to the second strip thickness L 2  being carried out on at least one wide side of the flat strip or being carried out on both oppositely situated wide sides of the flat strip. 
     
     
         6 . The inner fin according to  claim 5 , wherein the strip thickness reduction R from L 1  to L 2  is carried out on both oppositely situated wide sides of the flat strip by a constriction, approximately the same amount of the proportional strip thickness reduction R 1 , R 2  of approximately R 1 =(L 1 −L 2 )/2 and R 2 =(L 1 −L 2 )/2 being present on both wide sides. 
     
     
         7 . The inner fin according to  claim 5 , wherein the strip thickness reduction R from L 1  to L 2  is present on both sides of the neutral fibers of the strip, in particular approximately the same amount of proportional strip thickness reduction R 1 , R 2  of approximately R 1 =(L 1 −L 2 )/2 and R 2 =(L 1 −L 2 )/2 is present on both sides of the neutral fibers. 
     
     
         8 . The inner fin according to  claim 1 , wherein the metallic flat strip has a first strip thickness L 1 , which is essentially constant in the entire area of the wave crests and the wave troughs, and the flat metallic strip has a second strip thickness L 2 , which is essentially formed in the entire area of the web-like fin area. 
     
     
         9 . A flat tube comprising:
 a tube wall having two oppositely situated wide sides and two oppositely situated narrow sides;   a tube interior; and   an inner fin according to  claim 1 , the inner fin being arranged in the tube interior,   wherein the wave crests abut one of the two wide sides of the tube wall,   wherein the wave troughs abut the other of the two wide sides or the wave crests connected to one of the two wide sides of the tube wall, and   wherein the wave troughs are connected to the other of the two wide sides via, in particular soldered, welded or glued.   
     
     
         10 . The flat tube according to  claim 9 , wherein the wave crests are soldered on one of the two wide sides of the tube wall, and the wave troughs are soldered on the other of the two wide sides, wherein solder menisci made from solder material is formed between the strip and the wide sides, and wherein the web-like fin area has the second strip thickness L 2  being arranged between the solder menisci.