Patent ID: 6749014
Filing Date: 2004-06-15
Classification: F24B,F24D,F28D,Y02B

Abstract:
A heat exchanger for preheating domestic water by transferring heat from a flue containing combustion gases flowing therethrough comprising:said heat exchanger replacing a portion of said flue and having a single, tube for connecting the replaced portion of said flue to allow flow of combustion gases therethrough; said single tube being axially oriented with said flue; said single tube being smooth and unencumbered in an interior portion thereof; said single tube being enclosed by a cylindrical shell spaced from said single tube with caps at upstream and downstream ends of said shell for fully enclosing a space within said shell surrounding said single tube; helical tubing being located within said shell, said helical tubing having an inlet adjacent a downstream end of said helical tubing and an outlet adjacent an upstream end of said helical tubing; said shell having a pair of respective openings accommodating said inlet and said outlet of said helical tubings therethrough; said helical tubing within said shell coiled around said tube, said helical tubing connecting said inlet and outlet within said shell; a highly conductive conformable loose aggregate of fibrous material filling spaces within said shell between and around said helical tubing to increase heat transfer from combustion gases within said single tube to said helical tubing; said shell being made from insulating material and said end caps being heat resistant; and means for circulating water through said helical tubing from said inlet to said outlet of said helical tubing within said shell for heating said water.