Patent Abstract:
A gas water heater device includes a combustion chamber for providing a gas flow, a pipe assembly, and a heat exchanger disposed over the combustion chamber including a plurality of thermal conductors disposed in parallel with each other, each of the plurality of thermal conductors further comprising a base, a plurality of through holes accommodating the pipe assembly therethrough, and a flange for collecting condensed water formed on the base.

Full Description:
BACKGROUND OF THE INVENTION 
   The present invention generally relates to a water heater device and, more particularly, to a gas water heater and a method of operating the same. 
   Gas water heaters using natural gas such as LNG (liquefied natural gas), LPG (liquefied petroleum gas) or SG (synthetic gas) as fuel for heating water to a temperature level have been widely used.  FIG. 1  is a schematic diagram of a conventional water heater  10 . Referring to  FIG. 1 , the water heater  10  includes a combustion chamber  12 , a pipe assembly  14  and a heat exchanger  15 . High-temperature gas including carbon dioxide (CO 2 ) and vapor are generated after the combustion. Cold water from an inlet (not numbered) of the pipe assembly  14  is heated when it passes through the heat exchanger  15 . During the heating process, the heat exchanger  15  conducts a thermal exchange between the cold water and high-temperature gas. Consequently, hot water is supplied from an outlet (not numbered) of the pipe assembly  14 . The conventional water heater  10  usually has a thermal efficiency ranging from 70% to 83%, which means that a considerable amount of heat energy generated during the heating process is dissipated, generally in the form of waste gas. The temperature of the waste gas is approximately 200° C. (degrees Celsius). Moreover, the vapor may condense into water drops that will yield condensed water. The condensed water may adversely affect the combustion, and may even erode the pipe assembly  14  and the heat exchanger  15 . 
   It is desirable to have a gas water heater that is able to recycle waste gas so as to improve the thermal efficiency, and discharge condensed water, if any, in a more efficient manner. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention is directed to a gas water heater device and a method of operating the same that obviate one or more problems resulting from the limitations and disadvantages of the prior art. 
   In accordance with an embodiment of the present invention, there is provided a gas water heater device that comprises a combustion chamber for providing a gas flow, a pipe assembly, and a heat exchanger disposed over the combustion chamber including a plurality of thermal conductors disposed in parallel with each other, each of the plurality of thermal conductors further comprising a base, a plurality of through holes accommodating the pipe assembly therethrough, and a flange for collecting condensed water formed on the base. 
   Also in accordance with the present invention, there is provided a gas water heater device that comprises a combustion chamber for providing a gas flow, a pipe assembly, a first heat exchanger disposed over the combustion chamber including a plurality of thermal conductors disposed in parallel with each other, each of the plurality of thermal conductors further comprising a base, a plurality of through holes accommodating the pipe assembly therethrough, and a flange for collecting condensed water formed on the base, and a second heat exchanger disposed between the first heat exchanger and the combustion chamber. 
   Further in accordance with the present invention, there is provided a gas water heater device that comprises a combustion chamber for providing a gas flow, a pipe assembly, a heat exchanger disposed over the combustion chamber including a plurality of thermal conductors disposed in parallel with each other, each of the plurality of thermal conductors further comprising a base, a plurality of through holes accommodating the pipe assembly therethrough, and a first flange for collecting condensed water formed on the base, and a housing including a second flange for collecting water from the first flange of each of the plurality of thermal conductors. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The foregoing summary as well as the following detailed description of the preferred embodiments of the present invention will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It is understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
       FIG. 1  is a schematic diagram of a conventional water heater; 
       FIG. 2  is a schematic diagram illustrating a front elevational view, a top plan view and a right side elevational view of a thermal conductor of a heat exchanger in accordance with one embodiment of the present invention; 
       FIG. 3  is a schematic diagram illustrating a thermal conductor of a heat exchanger in accordance with another embodiment of the present invention; 
       FIG. 4A  is a schematic diagram illustrating a front elevational view, a top plan view and a right side elevational view of the interior of a housing of a heat exchanger in accordance with one embodiment of the present invention; 
       FIG. 4B  is a schematic diagram illustrating a front elevational view, a top plan view and a right side elevational view of the exterior of the housing illustrated in  FIG. 4A ; 
       FIG. 5  is a schematic diagram illustrating a front elevational view, a top plan view, a right side elevational view and a left side elevational view of a heat exchanger in accordance one embodiment of the present invention; and 
       FIG. 6  is a schematic diagram of a gas water heater in accordance with one embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 2  is a schematic diagram of a thermal conductor, generally designated  20 , of a heat exchanger in accordance with one embodiment of the present invention. Referring to  FIG. 2 , the thermal conductor  20  includes a base  21 , a plurality of through holes  22  and a flange  23 . The thermal conductor  20  is disposed over a combustion chamber (not shown) such that the normal direction of the base  21  is substantially orthogonal to the direction of a high-temperature gas flow  25  from the combustion chamber. The base  21  is made of a thermally conductive material such as copper in the form of a sheet. The plurality of through holes  22  provided on the base  21  allow passage of a pipe assembly, which is also made of a thermally conductive material. The flange  23  collects and discharges condensed water formed on the base  21  during a heating process. Given a household gas water heater, the flange  23  protrudes from the base  21  by a distance of approximately 1 mm (millimeter). The flange  23 , disposed at a lower part of the base  21 , has an inverted V shape with respect to the gas flow  25  to facilitate collection and discharge of the condensed water. 
     FIG. 3  is a schematic diagram illustrating a thermal conductor  30  of a heat exchanger in accordance with another embodiment of the present invention. Referring to  FIG. 3 , the thermal conductor  30  has a similar structure to the thermal conductor  20  illustrated in  FIG. 2  except it includes a plurality of surface scratches  32 . The scratches  32  increase the surface roughness of the base  21 , which helps prevent the gathering of condensed water drops by destroying their surface tension, and therefore prevent condensed water drops from plumb falling. The scratches  32 , extending in a direction substantially orthogonal to the direction of the gas flow  25 , may be formed by rubbing across a surface of the base  21  with an industrial sandpaper or by other process known to those skilled in the art. The laterally extending scratches  32  also help guide condensed water drops onto the flange  23 . 
     FIG. 4A  is a schematic diagram of the interior of a housing  40  of a heat exchanger in accordance with one embodiment of the present invention. Referring to  FIG. 4A , the housing  40  includes a plurality of through holes  42 , a flange  43  and a drain  46 . The through holes  42 , corresponding to the through holes of thermal conductors  20  or  30  of the heat exchanger, are provided on two sides of the housing  40  (only one is shown) to accommodate a pipe assembly. The flange  43 , as viewed from the AA′ and BB′ cross sections, is disposed at a lower part of the housing  40 . The flange  43  collects condensed water from the surfaces of the thermal conductors. The drain  46 , which may be disposed at a lower level than the flange  43 , serves as an outlet for discharge of the condensed water collected in the flange  43 . 
     FIG. 4B  is a schematic diagram of the exterior of the housing  40  illustrated in  FIG. 4A . Referring to  FIG. 4B , the housing  40  includes a top cover  47  and a bottom cover  48 , each of which further includes a protruding portion  47 - 1  and  48 - 1 , respectively, with respect to a side  44  of the housing  40 . The protruding portions  47 - 1  and  48 - 1  facilitate affixation of the heat exchanger to another heat exchanger, which will be discussed in following paragraphs. 
     FIG. 5  is a schematic diagram of a heat exchanger  50  in accordance with another embodiment of the present invention. Referring to  FIG. 5 , the heat exchanger  50  includes a plurality of thermal conductors  51 , such as fins, disposed in parallel with each other. A plurality of through holes  52 ,  52 - 1  and  52 - 2  are provided to accommodate a pipe assembly  54 . The pipe assembly  54  extends windingly from the through hole  52 - 1  through the heat exchanger  50  to the through hole  52 - 2 . The through holes  52 - 1  and  52 - 2  also serve as an inlet for cold water and an outlet for hot water, respectively. In the present example, the through hole  52 - 1  is positioned at a higher elevation than through hole  52 - 2 . A drain  56 , which corresponds to the flanges of the plurality of thermal conductors  51 , functions to discharge condensed water. The heat exchanger  50  may be mechanically affixed to another heat exchanger through flanges  59  by, for example, nuts and screws. 
     FIG. 6  is a schematic diagram of a gas water heater  60  in accordance with one embodiment of the present invention. Referring to  FIG. 6 , the gas water heater  60  includes a first heat exchanger  61 , a second heat exchanger  62 , a pipe assembly  64  and a combustion chamber  66 . The second heat exchanger  62  is preferably in the form of one of the above-mentioned embodiments shown in  FIGS. 2 to 5 . The first heat exchanger  61 , disposed between the second heat exchanger  62  and the combustion chamber  66 , may include, in one aspect, a conventional heat exchanger such as the heat exchanger  15  of the conventional gas water illustrated in  FIG. 1  or, in another aspect, could be another second heat exchanger as the second heat exchanger  62  as shown in  FIGS. 2 to 5 . 
   In operation, when the combustion chamber  66  is ignited, cold water provided from an inlet  64 - 1  to the second heat exchanger  62  is pre-heated by a gas flow  65 , specifically, a waste gas flow from the combustion chamber  66 . The pre-heated water flowing out of an outlet  64 - 2  of the second heat exchanger  62  is fed into the first heat exchanger  61  and then heated in the first heat exchanger  61 . Consequently, hot water is provided from an outlet  64 - 3  of the first heat exchanger  61 . The thermal efficiency of the gas water heater  60  is improved as compared to the conventional gas water heater illustrated in  FIG. 1  because the gas flow  65  is applied to the second heat exchanger  62  in addition to the first heat exchanger  61 , resulting in less waste of heat energy. The thermal efficiency of the gas water heater  60  may reach up to approximately 90% while the temperature of the waste gas flow may be reduced to 50° C. That is, a significant part of heat energy that would otherwise be wasted in the conventional design is recycled in the gas water heater  61  according to the present invention. 
   In describing representative embodiments of the present invention, the specification may have presented the method and/or process of the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention. 
   It will be appreciated by those skilled in the art that changes could be made to the preferred embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but is intended to cover modifications within the spirit and scope of the present application as defined by the appended claims.

Technology Classification (CPC): 5