Dual function high efficiency water heater

Abstract

This gas-fired water heater has a shell sealed at opposite ends within an insulated storage tank, defining a water-tight chamber with inlet and outlet water connections thereto. The shell preferably is a one-piece casting of aluminum alloy, with a circular array of impervious passages between its opposite ends. Each passage is defined by a curved wall segment spaced inwardly adjacent the tank and a pair of side walls converging inwardly from opposite ends of each curved wall segment to an inboard corner, where the adjacent corners and side walls are spaced apart radially and circumferentially respectively yielding water contact against all exterior passage surfaces. A burner under the storage tank generates hot flue gases that vent through the passages for heating the chamber water. A rib can project inwardly from the curved wall segment into each flow passage, adding heat transfer to the wall segment and contacted water.

1 - 27 . (canceled)  
   
   
       28 - 35 . (canceled)  
   
   
       36 . A gas-fired natural draft water heater, comprising the combination of 
 a vertically aligned insulated cylindrical water-tight sealed storage tank having lower and upper headers, a burner underlying the lower header operable to generate hot flue gases, and cold water inlet and hot water outlet connections in the tank for conveying water there through;    a water-tight thermally conductive flue pipe extending axially and generally concentrically of the storage tank between sealed end connections in the headers for conveying the flue gases through the tank, with the water in the tank being annular of and substantially contacting all of the exterior surfaces of the flue pipe;    said flue pipe having inlet and outlet end segments sealed to the headers and an intermediate segment larger in cross-section than the end segments;    said intermediate segment being continuous and comprised of consecutive upstream, intermediate and downstream contours, where said intermediate contour extends axially of the cylindrical tank, and said upstream and downstream contours are extended transversely of the cylindrical tank; and    an impervious baffle mounted in the intermediate flue pipe segment and disposed transversely of the cylindrical tank, with the baffle peripheral edge being spaced from the intermediate contour of the flue pipe segment operable for defining an annular flue gas flow path around the baffle and transversely of the tank wall for increasing heat transfer between the flue gas and adjacent tank water.    
   
   
       37 . A water heater according to  claim 36 , further comprising a coiled pipe in the annular chamber for absorbing and transferring heat from the hot water contained in said chamber to an additional water line.  
   
   
       38 . A gas-fired water heater, comprising the combination of 
 a vertically aligned insulated generally cylindrical storage tank, an inner shell within the tank, means sealing the shell and tank together at respective lower and upper ends whereby a closed water-tight chamber is defined therebetween, and inlet and outlet connections for the chamber operable to convey water there through;    said shell having a circular array of impervious axially extended passages between the lower and upper chamber ends, each passage being defined by exterior walls including a curved wall segment spaced inwardly adjacent the tank and a pair of side walls converging inwardly from the opposite ends of each curved wall segment to meet at an inboard liquid-tight corner, and the adjacent passage side walls and inboard corners being circumferentially and radially separated respectively defining starlike extensions of the chamber whereby chamber water can contact all of the exterior passage surfaces; and    a burner underlying the storage tank operable to generate hot flue gases; and headers adjacent respective lower and upper open ends of the passages for conducting said flue gases through the passages and away from burner and the water heater.    
   
   
       39 . A water heater according to  claim 38 , further comprising a radial rib extended inwardly from the curved wall segment into each flow passage, adding heating exposure to the wall segment from flue gases passing through the passages.  
   
   
       40 . A water heater according to  claim 38 , further comprising the curved wall segments together having their exterior surface shaped in general as a truncated cone smaller at  
   
   
       41 . A gas-fired water heater according to  claim 38 , further comprising the inner shell being cast as a single piece of an aluminum alloy.  
   
   
       42 . A water heater according to  claim 38 , with said means sealing the shell and tank together comprising the shell having an annular partially closed top end wall and an outwardly projected annular bottom end lip, and said tank overlying said shell and having an annular top end wall and an annular bottom end flange suited to butt flush against said shell top end wall and said bottom end lip, and means securing the end walls and said lip and flange together in sealed association.  
   
   
       43 . A water heater according to  claim 38 , further comprising a radial rib extended inwardly from the curved wall segment into each flow passage, adding heating exposure to the wall segment from flue gases passing through the passages, and the curved wall segments together having their exterior surface shaped in general as a truncated cone smaller at the upper end.  
   
   
       44 . A gas-fired water heater according to  claim 43 , further comprising the inner shell being cast as a single piece of an aluminum alloy.  
   
   
       45 . A water heater according to  claim 44 , with said means sealing the shell and tank together comprising the shell having an annular partially closed top end wall and an outwardly projected annular bottom end lip, and said tank overlying said shell and having an annular top end wall and an annular bottom end flange suited to butt flush against said shell top end wall and said bottom end lip, and means securing the end walls and said lip and flange together in sealed association.  
   
   
       46 . A water heater according to  claim 44 , further comprising a coiled pipe in the annular chamber for absorbing from the hot water contained in said chamber, and inlet and outlet connections through the tank operable to convey an additional water line to the coiled pipe.