Patent Publication Number: US-8113154-B2

Title: Transition element for a passage in a water heater

Description:
BACKGROUND 
     The present invention relates to water heaters, and more particularly to a transition element for a passage in a water heater. 
     SUMMARY 
     In one embodiment, the invention provides a water heater comprising a water tank adapted to contain water to be heated, a combustion chamber positioned proximate the water tank, a combustor positioned in the combustion chamber and operable to create products of combustion, a passage extending upwardly from the combustion chamber and through the water tank, the passage having an upper portion comprising an inner tube and an outer tube and a lower portion comprising an inner tube and an outer tube, and a transition element positioned in the passage and configured to direct a flow of supply air from the outer tube of the upper portion to the inner tube of the lower portion and deliver a flow of hot products of combustion from the outer tube of the lower portion to the inner tube of the upper portion, the transition element maintaining separation of the flow of supply air and the flow of products of combustion. 
     In another embodiment, the invention provides a water heater comprising a water tank adapted to contain water to be heated, a combustion chamber positioned proximate the water tank, a combustor positioned in the combustion chamber and operable to create products of combustion, a duct, a coaxial flue extending upwardly from the combustion chamber and through the water tank, the coaxial flue including an inner tube and an outer tube, and a transition element positioned between and communicating with the coaxial flue and the duct, the transition element configured to direct a flow of supply air to the inner tube of the coaxial flue and deliver a flow of products of combustion from the outer tube of the coaxial flue to the duct, the transition element maintaining separation of the flow of supply air and the flow of products of combustion. 
     In another embodiment, the invention provides a transition element positionable within a passage of a water heater, the passage extending upwardly through a water tank from a combustion chamber and having an upper portion having an inner tube and an outer tube and a lower portion having an inner tube and an outer tube. The transition element includes a first frustoconical section having a base and an opposite narrow end, the narrow end communicable with the inner tube of the upper portion. The first section also includes a first opening. The transition element further includes a second frustoconical section having a base and an opposite narrow end, the narrow end of the second section communicable with the inner tube of the lower portion, and the base of the second section communicable with the base of the first section. The second section also includes a second opening on a side opposite the first opening. The transition element further includes a dividing wall that extends inside the frustoconical sections and that divides the interior of the transition element into a first conduit extending between the second opening and the narrow end of the first frustoconical section and a second conduit extending between the first opening and the narrow end of the second frustoconical section. The first conduit is configured to deliver a flow of products of combustion from the outer tube of the lower portion to the inner tube of the upper portion, and the second conduit is configured to deliver a flow of supply air from the outer tube of the upper portion to the inner tube of the lower portion. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a water heater system embodying some aspects of the invention. 
         FIG. 2  is a cross-sectional view of the water heater system of  FIG. 1  taken along line  2 - 2  of  FIG. 1  and showing a passage and a transition element according to the invention. 
         FIG. 3  is a detailed view of the passage and transition element of  FIG. 2 . 
         FIG. 4  is a detailed view of the transition element of  FIG. 2 . 
         FIG. 5  is a perspective view of the transition element of  FIG. 2 . 
         FIG. 6  is a side view of the transition element of  FIG. 2 . 
         FIG. 7  is a top view of the transition element of  FIG. 2 . 
         FIG. 8  is a cross-sectional view of the transition element of  FIG. 2  taken along line  8 - 8  of  FIG. 7 . 
         FIG. 9  is a perspective view of a combustion chamber of  FIG. 2 . 
         FIG. 10  is a front view of the combustion chamber of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
       FIGS. 1 and 2  illustrate a water heater  10  embodying the invention. The water heater  10  comprises a water tank  20  for containing water to be heated, a base pan  30  supporting the water tank  20 , an outer jacket  40  surrounding the water tank  20 , insulation  50  between the tank  20  and the jacket  40 , a temperature and pressure relief valve  60 , a drain valve  70 , a cold water input  80 , a hot water output  90 , and a combustion chamber  100  positioned below the tank  20 . The water heater  10  further includes a passage  110  communicating with the combustion chamber  100  and extending substantially vertically through the water tank  20  and above the water tank  20 , and a transition element  120  positioned within the passage  110 . The water heater  10  also includes a control system  130  which may include temperature sensors, water sensors, a current sensor on the power circuit, a switch box or module, and an operator panel. Other constructions of the water heater can include different or additional control sensors, and it should be understood that not all of the components for the control system are required for all constructions. It is to be understood that the water heater  10  described herein is only for exemplary purposes. Other constructions of the water heater also fall within the scope of the invention. 
     As shown in  FIGS. 2 and 3 , the passage  110  is a coaxial passage that includes an upper portion  140  and a lower portion  150 . The passage is formed of galvanized steel; however, in other embodiments, the passage may be formed of other material. The lower portion  150  extends substantially vertically from the combustion chamber  100  through the water tank  20 . As illustrated, the lower portion  150  is a coaxial flue having an inner tube  170  and an outer tube  180 . The inner tube  170  is configured to direct supply air for combustion from the upper portion  140  of the passage  110  to the combustion chamber  100 . The outer tube  180  surrounds the inner tube  170  and is configured to deliver hot products of combustion from the combustion chamber  100  to the upper portion  140  of the passage  110 . In some embodiments, the inner tube has a 4-inch diameter and the outer tube has a 6-inch diameter. In still other embodiments, the inner tube has a 3-inch diameter and the outer tube has a 5-inch diameter. Other diameters are within the scope of the invention. 
     The upper portion  140  of the passage  110  is an L-shaped duct  190  that extends upward from the water tank  20 . As shown, the duct  140  has an inner tube or exhaust duct  200  and an outer tube  210 . The inner tube  200  conducts exhaust gasses or products of combustion, and the outer tube  210  conducts supply air. However, in other embodiments, the duct  190  can include only the tube or exhaust duct  200  for conducting exhaust gasses. Supply air can be drawn from the room air surrounding the water heater. The passage  110  also includes a transition section  215  connecting the outer tube  210  and the outer tube  180 . In alternative embodiments, the tubes  210  and  180  can be directly connected. 
     As shown in  FIGS. 2-4 , the transition element  120  is positioned within the passage  110  and communicates between the coaxial flue  150  and the duct  190 . In the illustrated construction, the transition element  120  is located in the transition section  215 . In alternative embodiments, in which the outer tubes  210  and  180  are directly connected, the transition element  120  can be located inside either of tubes  210  and  180 . The transition element  120  is configured to direct supply air from the outer tube  210  of the duct  190  to the inner tube  170  of the coaxial flue  150  and deliver hot products of combustion from the outer tube  180  of the coaxial flue  150  to the inner tube  200  of the duct  190 . The transition element  120  is further configured to maintain separation of the supply air and the products of combustion, such that the supply air and the products of combustion do not mix within the passage  110 . 
     As shown in  FIGS. 2-8 , the transition element  120  includes a first or upper frustoconical section  220  having a narrow end and an opposite base or wide end, and a second or lower frustoconical section  230  having a narrow end and an opposite base or wide end. The transition element  120  also includes a generally cylindrical middle section  235  connecting the base of the upper section  220  to the base of the lower section  230 . The middle section  235  fits tightly inside the transition section  215 , so that gasses do not flow around the transition element  120 . The upper frustoconical section  220  has therein, on one side thereof, an opening  236 . The lower frustoconical section  230  has therein, on the side opposite the opening  236 , an opening  238 . The transition element  120  also includes a generally cylindrical first or upper conduit section  250  that extends from the narrow end of the upper frustoconical section  220  and that extends into and sealingly communicates with the lower end of the inner tube  200 . The transition element  120  also includes a generally cylindrical second or lower conduit section  280  that extends from the narrow end of the lower frustoconical section  230  and that extends into and sealingly communicates with the upper end of the inner tube  170 . 
     The transition element  120  also includes a dividing wall  300  that extends inside the sections  220 ,  235  and  230 . The dividing wall divides the interior of the transition element  120  into first and second conduits  240  and  270 . The first conduit  240  communicates between the opening  238  and the upper conduit section  250 , or the narrow end of the section  220 , and thereby between the outer tube  180  of the coaxial flue  150  and the inner tube  200  of the duct  190 . The second conduit  270  communicates between the opening  236  and the lower conduit section  280 , or the narrow end of the section  230 , and thereby between the outer tube  210  of the duct  190  and the inner tube  170  of the coaxial flue  150 . Gasses or air flowing within the first conduit  240  and the second conduit  270  are separated by the wall  300  and do not mix. As best shown in  FIG. 4 , the dividing wall  300  is generally S-shaped in vertical cross section. 
     In other embodiments, the transition element may have other shapes or configurations configured to direct the supply air and the products of combustion through the passage. The transition element may be various sizes and shapes, such that the size and shape of the transition element is determined by the size of the passage. In other embodiments, the upper frustoconical section and the lower frustoconical section may comprise two separate elements. 
     The transition element  120  may be stamped, cast, or molded from polymeric materials suitable for the temperatures and flue products present in the passage of the water heater application. In some embodiments, the transition element may be integrally formed with the passage. However, in other embodiments, the transition element is removably positioned within the passage. Furthermore, since the transition element is positioned within the passage, the transition element does not add additional height to the water heater. The transition element allows for the water heater system to have better combustion qualities, such as lower nitrogen oxide emission and high efficiency as compared to a water heater construction without the transition element since the transition element allows for use of the coaxial flue construction. 
     As shown in FIGS.  2  and  9 - 10 , the combustion chamber  100  communicates with the coaxial flue  150  of the passage  110 . Fuel is supplied to a combustor or burner  310  positioned in the combustion chamber  100  through a fuel line having a gas valve. The illustrated burner  310  is inverted relative to a conventional burner, because the supply air is coming from above the burner  310 . In other embodiments, the supply air could be directed below the burner so that the burner need not be inverted. For example, the inner tube  170  could be extended downward and through the middle of the burner. In some embodiments, the burner may be shielded for protection from excessive heat. Additional or excessive heat may be used to increase the velocity of the fuel supply or gas stream through an orifice to the burner. Manifold pressure increases as a result of the excessive heat and the subsequent increases in velocity of the gas stream to the burner. 
     In operation, the burner  310  burns fuel supplied by the fuel line along with supply air drawn into the combustion chamber  100  through the inner tube  170  of the coaxial flue  150 . The burner  310  creates products of combustion that rise through the outer tube  180  of the coaxial flue  150  and heat the water in the water tank by conduction through the wall of the outer tube  180 . The flow of products of combustion is driven by natural convection, but may alternatively be driven by a blower unit communicating with the flue  150 . The products of combustion formed in the combustion chamber  100  flow upwardly through the outer tube  180  as shown by arrows  360  ( FIG. 2 ). The products of combustion then flow through the first conduit  240  of the transition element  120  to the inner tube  200  of the duct  190  for venting from the water heater  10 . 
     Similarly, supply air flows downwardly to the combustion chamber  100  as shown by arrows  370 . The supply air flows first through the outer tube  210 , through the second conduit  270  of the transition element  120 , and then through the inner tube  170  of the coaxial flue  150 . As the supply air is delivered to the combustion chamber  100 , the supply air in the inner tube  170  is in heat exchange relation with the hot gasses in the outer tube  180 , such that the hot gasses transfer heat to the cool supply air. Pre-heating of the supply air increases the rate of combustion in the combustion chamber. 
     The construction of the coaxial flue increases the surface area of the flue for increased heat exchange between the products of combustion and the water in the water tank. Because the inner tube is inside the outer tube, the outer tube has a greater diameter and thus a greater outside surface area for heat exchange with the water in the tank. 
     Various features and advantages of the invention are set forth in the following claims.