Abstract:
A storage-type water heater includes a tank enclosing a volume of water, the tank having an upper portion and a lower portion, a chamber adjacent the lower portion of the tank and adapted to at least partially enclose a source of a heated fluid, and a helical tube heat exchanger at least partially enclosed within the tank and fluidly connected to the chamber. The helical tube directs the heated fluid from the lower portion to the upper portion of the tank and promotes heat exchange between the water in the tank and the heated fluid flowing therethrough.

Description:
BACKGROUND 
     The present invention relates to water heaters. 
     SUMMARY 
     In one embodiment, the invention provides a storage-type water heater comprising: a water storage tank having a generally vertical center axis and having upper and lower ends; a combustion chamber adjacent the lower end of the tank; a burner generating products of combustion in the combustion chamber; a substantially straight flue tube extending within the tank generally along the axis, the flue tube having a closed lower end and having an open upper end; and a helical tube heat exchanger within the tank, the helical tube being generally centered on the axis, the helical tube having an upper end communicating with the flue tube at a point between the upper and lower ends of the flue tube, and the helical tube having a lower end communicating with the combustion chamber such that the products of combustion flow from the combustion chamber into the helical tube, then into the flue tube and then out of the upper end of the flue tube; a portion of the flue tube extending downward from the point at which the helical tube communicates with the flue tube so as to form a condensing water trap in the closed lower end of the flue tube. 
     In another embodiment, the invention provides a storage-type water heater comprising: a tank enclosing a volume of water, the tank having an upper portion and a lower portion; a chamber adjacent the lower portion of the tank and adapted to at least partially enclose a source of a heated fluid; and a helical tube heat exchanger at least partially enclosed within the tank and fluidly connected to the chamber, the helical tube directing the heated fluid from the lower portion to the upper portion of the tank and promoting heat exchange between the water in the tank and the heated fluid flowing through the helical tube. 
     In another embodiment, the invention provides a water heater comprising: a storage tank for supporting water therein, the storage tank having an upper portion and a lower portion; a burner chamber adjacent the lower portion of the tank and at least partially enclosing a burner for generating products of combustion; a helical tube heat exchanger at least partially enclosed within the tank and fluidly connected to the burner chamber, the helical tube directing a flow of the products of combustion in a direction generally defined from the lower portion to the upper portion of the tank and promoting heat exchange between the water in the tank and the products of combustion flowing therethrough; a substantially straight flue tube at least partially enclosed within the tank and extending upwardly to the upper portion of the tank, the helical tube being fluidly connected to the flue tube above a lower portion of the flue tube for directing the flow of the products of combustion from the lower portion of the tank to the upper portion of the tank; a condensing water trap system including a water tube extending from the lower portion of the flue tube to the exterior of the tank, the condensing water trap system being operable to collect water condensed within the flue tube at the lower portion thereof and direct the condensed water through the water tube to the exterior of the tank; and a blower coupled to the upper portion of the tank and fluidly connected to an upper portion of the flue tube, the blower being operable to affect the products of combustion to at least partially generate the flow of the products of combustion from the burner chamber through the helical tube and then through the flue tube. 
     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 an elevation view of a water heater with a helical tube heat exchanger according to one embodiment of the present invention. 
         FIG. 2  is a perspective view of a water heater according to another embodiment of the present invention. 
         FIG. 3  is another perspective view of the water heater in  FIG. 2  with additional parts cut away. 
         FIG. 4  is a partial perspective view of water heater according to another embodiment of the present invention. 
     
    
    
     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. 
       FIG. 1  illustrates a storage-type water heater  10  according to one embodiment of the present invention. The water heater  10  includes a tank  20  having a top head  25  and a bottom head  30 . The tank  20  contains potable water and has a generally vertical center axis  115 . The water heater  10  also includes an insulating jacket  35  surrounding the tank  20 , an open combustion chamber  40  beneath the tank  20 , a burner  45 , a helical tube heat exchanger  50  fluidly connected to the chamber  40 , a substantially straight flue tube  55  connected to the helical tube  50 , a blower system  60  mounted on the top of the water heater  10 , and a water tube  65  connected to the lower end of the flue tube  55 . A water inlet pipe  70  and a water outlet pipe  75  (illustrated in  FIGS. 2 and 3 ) direct cold water into the tank  20  and hot water out of the tank  20 , respectively. It is to be understood that the water heater  10  described herein is only for exemplary purposes. Further, other types of water heaters fall within the scope of the invention. 
     During operation of the water heater  10 , fuel (e.g., gas) is provided to the burner  45  through a conduit  80  and a valve  82 . The fuel flows from the valve  82  to a manifold  84  for evenly distributing the fuel through the burner  45 . The burner  45  generates hot gasses or products of combustion in the chamber  40  such that heat is exchanged between the products of combustion and water in the tank  20 . More specifically, the products of combustion heat the bottom head  30 , which in turn heats the adjacent water. The products of combustion then flow upwardly from the chamber  40 , through the helical tube  50  and then through the flue tube  55  so that heat is exchanged between the products of combustion flowing within the tubes  50 ,  55  and the water around the tubes  50 ,  55 . In other words, the products of combustion flow in a direction defined from the lower portion to the upper portion of the tank  20 . 
     In the illustrated construction, the lower end of the helical tube  50  is coupled to the center of the bottom head  30 . Any suitable means, including welding, soldering or brazing can be used to connect the helical tube  50  to the bottom head  30 . The lower end of the helical tube  50  is aligned with the center axis  115 . Preferably, the entire helical tube  50  is centered on or defines a substantially constant radius around the axis  115 . In addition, the flue tube  55  extends along the axis  115 . Other configurations of the helical tube  50  and flue tube  55  with respect to the axis  115  and/or water heater  10  fall within the scope of the invention. In the illustrated construction, the tubes  50 ,  55  are manufactured of a steel material. However, the tubes  50 ,  55  can be manufactured with other suitable materials for promoting heat exchange between the products of combustion and the water within the tank  20 . Suitable materials include, but are not limited to, aluminum, cooper and other metal alloys. 
     In the illustrated construction, the tubes  50 ,  55  include diameters ranging between about 2.5 inches and about five inches. Further, the helical tube  50  has a smaller diameter than the flue tube  55 . It is to be understood that other dimensions (e.g., diameter) of the tubes  50 ,  55  fall within the scope of the invention. For example, it is contemplated that the tube  50  and the tube  55  include substantially the same diameter. In addition, it is within the scope of the invention that augmentation surfaces (e.g., baffles, fins) be incorporated to the tubes  50 ,  55  or other features of the water heater  10  to further promote heat exchange between the products of combustions flowing within the tubes  50 ,  55  and the water surrounding the tubes  50 ,  55 . 
     Condensate water can form on the inner wall of the flue tube  55 . To help avoid clogging or other problems associated with the forming of condensate water, the flue tube  55  forms a water condensation trap. More specifically, the flue tube  55  extends downwardly from where the helical tube  50  communicates with the flue tube  55 , and the flue tube  55  has a closed lower end for collecting condensate water. To dispose of the condensate water, the water tube  65  is connected to the lower end of the flue tube  55  and directs the condensate water downwardly and through the bottom head  30  to the chamber  40 . Generally, condensate water evaporates in the chamber  40 . However, in an alternate embodiment, the water tube  65  can extend from the chamber  40  and out of the water heater  10  as illustrated with in  FIGS. 2 and 3 . 
     The blower system  60  includes a blower  125  and a motor  135  driving the blower  125 . Although particular details of the blower  125  and motor  135  are not shown, the blower/motor combination is well known in the art of water heaters and further description is not necessary. The blower  125  communicates with the upper end of the flue tube  55  and increases and/or helps regulate the flow of the products of combustion from the chamber  40 , through the helical tube  50  and the flue tube  55 . 
       FIGS. 2 and 3  illustrate a water heater  210  according to an alternative embodiment of the present invention. The water heater  210  includes much of the same structure and has many of the same properties as the water heater  10  described above in connection with  FIG. 1 , and common elements have the same reference numerals. The following description focuses primarily upon the structure and features that are different from the water heater  10 . Particularly, the water heater  210  includes a base pan  15  for supporting the water heater  210 . Although not shown, the base pan  15  can include one or more apertures allowing air therethrough to the chamber  40  for generating products of combustion. In addition, the water tube  65  extends through the bottom head  30  and out of the jacket  35  from the combustion chamber  40  to a water disposal system (not shown). Other constructions of the water heaters  10 ,  210  can include the water tube  65  having a different configuration to dispose of the condensate water. 
       FIG. 4  illustrates a water heater  310  according to an alternative embodiment of the present invention. The water heater  310  includes much of the same structure and has many of the same properties as the water heater  10  described above in connection with  FIG. 1 , and common elements have the same reference numerals. The following description focuses primarily upon the structure and features that are different from the water heater  10 . Particularly, the flue tube  55  of the water heater  310  includes a tube portion  138  and a separation chamber  140  connected to the lower end of the tube portion  138 . The separation chamber  140  defines the closed lower end of the flue tube  55 . Particularly, the chamber  140  is defined by a substantially cylindrical wall  142  centered on the axis  115  and defining a diameter greater than the diameter of the tube portion  138 . Thus, the separation chamber  140  has a greater cross-sectional area than the tube portion  138 . In addition, the chamber  140  is defined by an upper wall  144  receiving the tube portion  138 , and a lower wall  146  receiving the water tube  65  for disposing the condensate water. 
     The helical tube  50  is connected to the chamber  140  such that the products of combustion flow from the helical tube  50  to the chamber  140 , and out of the chamber  140  to the tube portion  138  of the flue tube  55 . In the illustrated construction, the helical tube  50  is tangentially connected to the chamber  140 . In other words, the portion of the helical tube  50  connecting to the chamber  140  is substantially tangential to the cylindrical wall  142 . Tangentially connecting the helical tube  50  to the chamber  140  causes the products of combustion entering the chamber  140  to define a substantially circular fluid motion therein. The swirling motion of the products of combustion within the chamber  140  helps separate condensate water from the products of combustion. Other embodiments of the water heater  310  include different connection arrangements between the helical tube  50  and the flue tube  55 . For example, in one alternate embodiment, the connection of the helical tube  50  to the chamber  140  is not tangential. 
     It should be noted that the helical tube  50  of the water heater  10  could be tangentially connected to the flue tube  55 . 
     Various features and advantages of the invention are set forth in the following claims.