Heat exchanger

Abstract

The invention is a shell and tube type heat exchanger that provides a greater heat transfer coefficient to pressure drop ratio. The invention includes a mini-vortex generator on the surface of tubes within the tube bundle in the shell of the heat exchanger. The mini-vortex generator increases the heat transfer coefficient for grid baffle type heat exchangers having a longitudinal shell fluid flow without resulting in a significant increase in pressure drop. The invention also includes a sinuous-type grid baffle which permits a greater tube packing density and reduced pressure drop in a heat exchanger having longitudinal shell fluid flow. The invention also encompasses a shell and tube heat exchanger having mini-vortex generators and sinuous baffles.

1 - 16 . (canceled)  
   
   
       17 . A heat exchanger comprising: 
 (a) a shell;    (b) a tube bundle inside the shell, the tube bundle comprising a plurality of substantially parallel tubes for passage of a first fluid, each tube having a base diameter of between about 0.5″ and about 1″, at least a portion of the tubes having on their exterior surface mini-vortex generators comprising two or more ridge members that encircle at least a portion of the exterior surface of a tube, the height of each ridge member being between about 0.2 mm and about 1.0 mm, the spacing between any two ridge members being between about 2 mm and about 40 mm;    (c) a grid baffle for supporting the tubes;    (d) a tube inlet for passage of the first fluid into the tubes and a tube outlet for passage of the first fluid out of the tubes;    (e) a shell inlet for passage of a second fluid into the shell and exterior of the tubes and a shell outlet for withdrawing a second fluid from the shell, wherein the first and second fluid are passed either countercurrent, co-current, or in multi-pass substantially parallel flow, and when the fluids are at different temperatures, a transfer of heat occurs between the fluids.    
   
   
       18 . The heat exchanger of  claim 17  wherein the ridge members have a flow blocking surface that disrupts the longitudinal flow of the second fluid proximal to the exterior surface of the tubes.  
   
   
       19 . The heat exchanger of  claim 18  wherein the ridge members further comprise a sloped surface disposed downstream of the flow blocking surface.  
   
   
       20 . The heat exchanger of  claim 17  wherein the spacing between any two ridge members is between 2.6 mm and about 13 mm.  
   
   
       21 . The heat exchanger of  claim 17  wherein the spacing between any two ridge members is between about 10 times and about 15 times the height of the ridge members.  
   
   
       22 . The heat exchanger of  claim 17  wherein the ridge members are integral with the tubes.  
   
   
       23 . The heat exchanger of  claim 17  wherein: 
 the tubes are oriented along a longitudinal axis; and    the ridge members are disposed perpendicular to the longitudinal axis of the tubes.    
   
   
       24 . The heat exchanger of  claim 17  wherein the ridge members are annular rings protruding from the external surface of the tubes.  
   
   
       25 . The heat exchanger of  claim 17  wherein: 
 the tubes are oriented along a longitudinal axis; and    the ridge members are spiral shaped and wind around the external surface of the tubes along the longitudinal axis.    
   
   
       26 . A method of exchanging heat between two fluids comprising: 
 obtaining a heat exchanger according to  claim 17;     pumping a first fluid through the tubes in the tube bundle; and    pumping a second fluid through the shell to transfer heat between the first fluid and the second fluid.