Convoluted heat shield

Abstract

A heat shield comprises a convoluted tube preferably formed from two layers of aluminum. The convoluted tube may have an inside minor diameter ranging from 0.5 inches to 3.0 inches and preferably includes convolutions of greater than 0.070 inches and a pitch of at least 0.787 inches. Optionally, the tube is coated with a dark colored or black material to further enhance the heat shielding and dispersing properties. The present invention also includes a method of manufacturing the convoluted tube, and a method of shielding heat from an automobile EGR utilizing an aluminum convoluted tube having convolutions of at least 0.070 inches.

1 . A heat shield, comprising: 
 an elongated convoluted tubing having a plurality of convolutions, the elongated tubing consisting essentially of a first layer of aluminum and a second layer of aluminum.    
   
   
       2 . The heat shield as recited in  claim 1 , wherein, 
 the convolutions comprise a height equal to a difference between a major outside diameter of the heat shield and a minor inside diameter of the heat shield,    the height of the convolutions is at least 0.070 inches; and,    the minor inside diameter is approximately 0.50 inches.    
   
   
       3 . The heat shield as recited in  claim 2 , wherein the pitch of the convolutions is at least 0.787 inches.  
   
   
       4 . The heat shield as recited in  claim 1 , wherein, 
 the convolutions comprise a height equal to a difference between a major outside diameter of the heat shield and a minor inside diameter of the heat shield,    the height of the convolutions is at least 0.090 inches; and,    the minor inside diameter is between 0.75 inches and 3.0 inches.    
   
   
       5 . The beat shield as recited in  claim 4 , wherein a pitch of the convolutions is at least 0.118 inches.  
   
   
       6 . The heat shield as recited in  claim 4 , wherein the minor inside diameter is about 0.75 inches, and the convolution height is about 0.094 inches.  
   
   
       7 . The heat shield as recited in  claim 6 , wherein a pitch of the convolutions is at least about 1.18 inches.  
   
   
       8 . The heat shield as recited in  claim 4 , wherein the minor inside diameter is about 1.0 inches and the convolution height is about 0.098 inches.  
   
   
       9 . The heat shield as recited in  claim 8 , wherein a pitch of the convolutions is at least about 1.18 inches.  
   
   
       10 . The heat shield as recited in  claim 4 , wherein the minor inside diameter is about 2.0 inches and the convolution height is about 0.110 inches.  
   
   
       11 . The heat shield as recited in  claim 10 , wherein a pitch of the convolutions is at least about 1.18 inches.  
   
   
       12 . The heat shield as recited in  claim 4 , wherein the minor inside diameter is about 3.0 inches and the convolution height is about 0.118 inches.  
   
   
       13 . The heat shield as recited in  claim 12 , wherein a pitch of the convolutions is at least about 1.37 inches.  
   
   
       14 . The heat shield as recited in  claim 4 , wherein the heat shield further consists of a black outer coating.  
   
   
       15 . The heat shield as recited in  claim 4 , further comprising an end cap attached to at least one end of the tubing.  
   
   
       16 . A method of shielding heat generated from an automobile exhaust gas recirculation system (EGR), the EGR having a conduit for diverting exhaust gas, the method comprising: 
 at least partially surrounding the conduit with a convoluted tube, wherein the convoluted tube consists essentially of two layers of aluminum, the convoluted tube including convolutions comprising a height equal to a difference between a major outside diameter of the convoluted tube and a minor inside diameter of the convoluted tube, wherein,    the height of the convolutions is at least 0.090 inches; and, the minor inside diameter is between about 0.75 inches and about 3.0 inches.    
   
   
       17 . The method as recited in  claim 16 , wherein the pitch of the convolutions are at least about 1.18 inches.  
   
   
       18 . The method as recited in  claim 17 , wherein the tube further comprises a dark-colored coating.  
   
   
       19 . A method of forming a convoluted tube, comprising: 
 wrapping layers of aluminum around a mandrel having a diameter of 0.5 inches to 3.0 inches, wherein at least one of the layers includes an adhesive;    passing the wrapped layers between a worm and nut die to convolute the material, wherein the worm and the nut each have a thread height of at least 0.063 inches and a pitch of at least 0.787 inches; and,    passing the convoluted layers through a heat zone to thermally set the adhesive and substantially bond the layers together.    
   
   
       20 . The method as recited in  claim 19 , wherein the diameter of the convoluted tube is between 0.75 inches and 3.0 inches, the thread height is at least 0.075 inches, and the pitch is at least about 1.18 inches.