Method of forming heat exchanger tubes

Abstract

The invention relates to a method for manufacturing tubes, in particular for heat exchangers, composed of endless ribbons on a roller mill, wherein the tubes are composed of at least two ribbons which are subjected to a shaping process on the roller mill, wherein perforations or predetermined break points are introduced into the ribbons at predetermined locations, wherein a step of making the perforations in the ribbons is carried out, after which the ribbons are combined to form the tube and after which individual tubes are separated off at the predetermined locations. The formation of the perforations or the predetermined break points in at least one of the two ribbons is performed within or at the end of the shaping process of the corresponding ribbon so that some of the pairs of rollers do not require a drive.

1 . A method of manufacturing heat exchanger tubes, the method comprising the acts of:
 subjecting at least two endless ribbons to a shaping process on a roller mill;   perforating or forming predetermined break portions on at least one of the ribbons at a predetermined location before the at least two ribbons are combined to form a tube; and   separating individual tubes from the tube after the tube is formed;   wherein the perforations or predetermined break portions are formed during or subsequent to the shaping process of the at least one of the ribbons.   
   
   
       2 . The method of  claim 1 , wherein the shaping of the ribbons is, if necessary, performed again in an area near to the perforation or the predetermined break portions after it has been formed. 
   
   
       3 . The method of  claim 1 , wherein one of the at least two ribbons in which the perforations or the break portions are formed after the shaping is a corrugated internal insert of the flat tube. 
   
   
       4 . The method of  claim 1 , wherein the perforations are either at least one slot with two webs or can be linear ribbon thinning lines which constitute the predetermined break points. 
   
   
       5 . The method of  claim 4 , wherein the webs are constructed on two longitudinal edges of a corrugated internal insert. 
   
   
       6 . The method of  claim 4 , wherein further webs can be constructed depending on a width of a corrugated internal insert or of the ribbons. 
   
   
       7 . The method of  claim 1 , wherein a third ribbon is provided which constitutes the corrugated internal insert of the tubes, wherein the third ribbon is perforated after the construction of the corrugations, in that the perforations of the third ribbon are also made to correspond to the perforations of the two ribbons, and that the three ribbons are joined to form the tube. 
   
   
       8 . The method of  claim 1 , wherein the separating is performed by one of breaking, cutting, and tearing. 
   
   
       9 . The method of  claim 1 , wherein the perforation or the breaking of the ribbons is performed by rollers. 
   
   
       10 . A roller mill for manufacturing tubes from at least two endless ribbons, the mill comprising:
 at least one perforation station;   a section for shaping the ribbons to form the tubes;   a separating station for tubes; and   a section for perforating the ribbons;   wherein the perforation station is arranged behind or inside the shaping station.   
   
   
       11 . The roller mill of  claim 10 , wherein the perforation station is adjoined by at least one pair of rollers in order to shape of the ribbons again. 
   
   
       12 . The roller mill of  claim 10 , wherein a number of perforation stations corresponds to a number of the at least two endless ribbons. 
   
   
       13 . A flat heat exchanger manufactured according to  claim 1 . 
   
   
       14 . A heat exchanger including flat tubes manufactured according to  claim 1 .