Cooling pipe

Abstract

A coolant pipe may include a micro fin including a rib and a channel which are continuously disposed on an interior circumference of the coolant pipe thereby forming a spiral flow path while the coolant passes the coolant pipe. In particular, a protruding height of the rib is between 30 μm and 200 μm.

What is claimed is: 
     
         1 . A coolant pipe for flowing coolant, comprising;
 a micro fin including a rib and a channel which are continuously disposed on an interior circumference of the coolant pipe, the micro fin configured to form a spiral flow path while the coolant passes through the coolant pipe,   wherein a protruding height of the rib is between 30 μm and 200 μm.   
     
     
         2 . The coolant pipe of  claim 1 , wherein the micro fin forms a helix angle with respect to a longitudinal direction of the coolant pipe. 
     
     
         3 . The coolant pipe of  claim 2 , wherein the helix angle is from 35 degree to 45 degree with respect to the longitudinal direction of the coolant pipe. 
     
     
         4 . The coolant pipe of  claim 1 , wherein the rib has a triangular cross-sectional shape. 
     
     
         5 . The coolant pipe of  claim 1 , wherein the rib has an oval cross-sectional shape. 
     
     
         6 . The coolant pipe of  claim 1 , wherein the rib has a rectangle cross-sectional shape and rounded corners. 
     
     
         7 . The coolant pipe of  claim 1 , wherein the rib has a rectangle cross-sectional shape and right angle corners. 
     
     
         8 . The coolant pipe of  claim 1 , wherein the rib and the channel are made of stainless steel. 
     
     
         9 . An exhaust gas recirculation (EGR) cooler including the coolant pipe according to  claim 1 , and a cooler housing,
 wherein the cooler housing and the coolant pipe are attached by brazing and welding so that the coolant flows into or out of the cooler housing through the coolant pipe.