Abstract:
An apparatus to heat potable water aboard a recreational marine watercraft includes a metal enclosure that sits atop one burner of a conventional galley stove powered separately from the engine and the source of AC power. Potable water is circulated through a tubing unit mounted within the enclosure by a pump operated by a low DC voltage. The heated potable water is then transferred back to the potable water holding tank through a check valve which prevents reversed flow of the heated water. This provides a boater with the ability to maintain a source of hot water while away from shore power or while the engine is turned off. The top of the enclosure is partially open to allow use of the burner for cooking, or boiling water as needed with the cooking vessel being placed atop of the enclosure.

Description:
RELATED APPLICATIONS 
     The present invention was first described in and claims the benefit of Disclosure Document No. 609,991 filed on Dec. 7, 2006. 
     FIELD OF THE INVENTION 
     The present invention relates, in general, to marine heat exchangers and, more particularly, this invention relates to an apparatus for equipping a conventional marine cooking stove with a heat exchanger that is energized independently from the recreational marine watercraft engine or AC shore power to heat potable water for onboard purposes or separately for cooking needs. 
     BACKGROUND OF THE INVENTION 
     As is generally well known, recreational boating has earned a well-deserved spot on the list of favorite pastimes of countless people. The ability to go anywhere, virtually anytime, with all of the comforts of home makes it truly enjoyable. Whether one travels in a smaller boat or in a larger multi-level yacht, one is ensured of seeing all that the sea and surrounding land has to offer with a minimum impact on cost and a maximum impact on fun. However, one disadvantage associated with many recreational marine watercrafts is the inability to heat water when not docked or when the engine is turned off. Most watercrafts use AC shore power to electrically heat water for cooking, bathing, and cleaning. When away from dock, such watercrafts must rely on a generator which is not always feasible due to its weight and size considerations. Accordingly, there exists a need for a means by which watercrafts can be provided with the ability to heat water at any time without the reliance on AC electrical power or engine operation. 
     Several attempts have been made in the past to provide a liquid heating and circulation system. U.S. Pat. No. 4,249,491, issued in the name of Stein, discloses a multiple liquid heating and circulating system, Unfortunately, the Stein invention is particularly useful for maintaining equipment, especially engines, when they are non-operational 
     U.S. Pat. No. 6,6332,580, issued in the name of Enander et al., teaches a compact vehicle heating system and method, wherein the system selectively shut down heating systems with respect to the demand for domestic hot water. Unfortunately, the Enander et al. device is not particularly suited for use onboard a watercraft and therefore differs in scope. 
     U.S. Pat. No. 6,612,504, issued in the name of Sendzik, describes a heating system for heating fresh water on marine vessels, wherein the vessel&#39;s water supply is connected to a hot water tank in fluid communication with a heat exchanger. The vessel&#39;s engine coolant line passes through the heat exchanger, wherein heat is exchanged with the coolant line, which in turn heats the water within the heat exchanger, with a flow regulator for the water line. Unfortunately, the Sendzik device does not provide for a heat exchanger that operates in conjunction with the convected heat emanating from an onboard cooking apparatus, such as a stove top. 
     None of the prior art particularly describes a system for heating and circulating water aboard a recreational watercraft. 
     SUMMARY OF THE INVENTION 
     According to one aspect, the present invention provides an apparatus for heating water aboard a recreational marine watercraft independently from a source of AC power or independently from operation of the watercraft&#39;s engine. The apparatus includes a heat exchanger which is operably connected to each of a source of heat and a source of water. The heat exchanger is capable of transferring heat generated by the source of heat to the water circulating through the heat exchanger. A water supply conduit is provided for delivering water from the source of water to the heat exchanger. There is also provided a water return conduit for returning heated water from the heat exchanger to the source of water. A pump is electrically coupled to a source of DC power. The pump is operable for selectively circulating the water from and to the source of water through the heat exchanger. A valve is operably mounted within the water return conduit for preventing a reversed flow of the water therein. 
     According to another aspect, the instant invention provides an apparatus for heating potable water. The apparatus includes a heat exchanger which is operably connected to each of a source of heat and a source of water. The heat exchanger is capable of transferring heat generated by such source of heat to the water circulating therethrough. The heat exchanger has an enclosure formed by a top panel, a bottom panel and a peripheral side panel. A heating tube unit is mounted within the enclosure and has a pair of ends extending through a portion of one of the peripheral side panel and the top panel. An aperture is formed in one of the bottom panel and the top panel of the enclosure for directly exposing the heating tube unit to the heat generated by the heat source. A water supply conduit is provided for delivering water from the source of water to the heat exchanger. There is also provided a water return conduit for returning heated water from the heat exchanger to the source of water. A pump is operably mounted within the water supply conduit. The pump is electrically coupled to a source of DC power. The pump is operable for selectively circulating the water from and to the source of water through the heat exchanger. A valve is operably mounted within the water return conduit for preventing a reversed flow of the water therein. 
     According to yet another aspect of the present invention there is provided a method of heating potable water aboard a recreational marine watercraft independently from a source of AC power or operation of the watercraft&#39;s engine. The method includes the step of positioning a heat exchanger in abutting engagement with a top portion of a burner mounted atop a stove of the watercraft for generating heat sufficient to heat the potable water. Positioning a pump and a check valve in a predetermined location within the watercraft. Connecting the pump in fluid communication with an outlet of a tank containing potable water and an inlet of the heat exchanger. Connecting the valve in fluid communication with an inlet of the tank and an outlet of the heat exchanger. Connecting the pump to a source of DC power. Energizing the pump to circulate the potable water from and to the tank through the heat exchanger when the potable water is at a first pre-selected temperature. Finally, de-energizing the pump when the potable water is heated to a second pre-selected temperature. 
     It is, therefore, one of the primary objects of the present invention to provide a heat exchanger apparatus that is energized separately from a recreational marine watercraft engine or AC shore power to heat potable water for onboard purposes. 
     Another object of the present invention is to provide a heat exchanger apparatus for watercraft that contains a heat exchanging unit capable of being placed atop of a burner of an existing cooking stove. 
     Yet another object of the present invention is to provide a heat exchanger apparatus for watercraft that includes a circulating pump and a thermostat switch for automatically energizing and de-energizing the pump. 
     A further object of the present invention is to provide a heat exchanger apparatus for watercraft that enables heating a cooking vessel placed atop the heat exchanger. 
     Yet a further object of the present invention is to provide a heat exchanger apparatus for watercraft which is simple to install and connect. 
     An additional object of the present invention is to provide a heat exchanger apparatus for watercraft which is simple to disconnect and remove. 
     In addition to the several objects and advantages of the present invention which have been described with some degree of specificity above, various other objects and advantages of the invention will become more readily apparent to those persons who are skilled in the relevant art, particularly, when such description is taken in conjunction with the attached drawing Figures and with the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages and features of the present invention will become better understood with reference to the following more detailed description and claims taken in conjunction with the accompanying drawings, in which like elements are identified with like symbols, and in which: 
         FIG. 1  is a process flow diagram of a heat exchanger apparatus for recreational marine watercraft, which is constructed according to a presently preferred embodiment of the invention; 
         FIG. 2  is a perspective view of the heat exchanger portion of the recycle heat exchanger apparatus of  FIG. 1 ; 
         FIG. 3   a  is an enlarged view of the heat exchanger portion of the recycle heat exchanger apparatus of  FIG. 2 ; 
         FIG. 3   b  is a bottom view of the heat exchanger portion of the recycle heat exchanger apparatus of  FIG. 2 ; and, 
         FIG. 4  is an electrical block diagram of the heat exchanger apparatus of  FIG. 1 . 
     
    
    
     
       
         
               
             
               
               
             
           
               
                   
               
               
                 DESCRIPTIVE KEY 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 heat exchanger apparatus for watercraft 
               
               
                 20 
                 heat exchanger 
               
               
                 21 
                 bottom panel 
               
               
                 22 
                 thermostat wire 
               
               
                 24 
                 top panel 
               
               
                 25 
                 thermostat switch 
               
               
                 26 
                 inlet tube 
               
               
                 27 
                 outlet tube 
               
               
                 28 
                 side panel 
               
               
                 30 
                 pump 
               
               
                 31 
                 12-volt plug 
               
               
                 32 
                 heating tube unit 
               
               
                 33 
                 top aperture 
               
               
                 34 
                 bottom apeture 
               
               
                 40 
                 check valve 
               
               
                 41 
                 first quick coupler 
               
               
                 42 
                 second quick coupler 
               
               
                 50 
                 supply line 
               
               
                 55 
                 return line 
               
               
                 60 
                 holding tank 
               
               
                 70 
                 stove 
               
               
                 71 
                 burner 
               
               
                   
               
             
          
         
       
     
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The best mode for carrying out the invention is presented in terms of its preferred embodiment, herein depicted within  FIGS. 1 through 3   b . However, the invention is not limited to the described embodiment and a person skilled in the art will appreciate that many other embodiments of the invention are possible without deviating from the basic concept of the invention, and that any such work around will also fall under scope of this invention. It is envisioned that other styles and configurations of the present invention can be easily incorporated into the teachings of the present invention, and only one particular configuration shall be shown and described for purposes of clarity and disclosure and not by way of limitation of scope. 
     The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. 
     The present invention teaches an apparatus and method for a recycle heat exchanger for watercraft (herein described as the “apparatus”), generally designated  10 , which provides a means for heating potable water aboard a recreational marine watercraft independently from a source of AC power or independently from operation of a watercraft&#39;s engine. The apparatus  10  comprises a metal heat exchanger  20  operably connected to at least one heat source. It is presently preferred for such heat source include at least one burner  71  of a conventional galley stove  70 , whereby the bottom surface of the heat exchanger  20  abuttingly engages a top surface of the burner  71 . Potable water is circulated between the heat exchanger  20  and a hot water holding tank  60  using a circulating pump  30 . The hot water holding tank  60  may be an existing tank for holding potable water of the watercraft (not shown) or may be provided with the apparatus  10  in addition to the existing potable water holding tank. This provides a watercraft operator/user the ability to maintain a source of hot water while away from shore power or while the watercraft&#39;s engine is turned off. 
     Referring now to  FIG. 1 , a plumbing diagram of the apparatus  10 , according to the presently preferred embodiment of the invention, is illustrated. The apparatus  10  provides a closed recirculating potable water system comprising interconnecting supply line  50  and return line  55 , a pump  30 , an inlet tube  26 , the heat exchanger  20 , an outlet tube  27 , a check valve  40 , a 12-volt plug  31 , and a thermostat wire  22 . The supply line  50  transports potable water from the on-board holding tank  60  to the suction side of a pump  30  and then from the discharge side of the pump  30  to the heat exchanger  20 . The return line  55  delivers heated potable water from the heat exchanger  20  to the check valve  40  and then to the holding tank  60 . The supply and return lines  50 ,  55  are envisioned to be made of suitable marine materials such as polyvinylchloride (PVC), stainless steel, or the like, and are to be supplied with all necessary pipe/tubing fittings including drain plugs for off-season drainage and storage. The pump  30  is envisioned to be a commercially available miniature 12-volt DC marine-duty unit. The pump  30  is to be capable of a minimum flow of ½ gallon per minute. Electrical power is provided to the pump  30  by an existing 12-volt DC power circuit using a standard 12-volt plug  31 . However, it is within the scope of the present invention to utilize a conventional 12-volt battery (not shown) if required. Potable water flow continues from the pressure side of the pump  30  through the supply line  50  to the inlet tube  26 . The inlet tube  26  is a common copper tubing approximately ⅜ inches in diameter. The inlet tube  26  passes horizontally through a peripheral vertical side panel  28  at a rear location of the heat exchanger  20 . As was noted earlier, the heat exchanger  20  is designed to rest atop the at least one burner  71  of the existing watercraft&#39;s stove  70 , thereby exchanging heat generated from the burner  71  to the potable water flow. However, it is within the scope of the present invention to use other heat sources which are operable independently from the source of AC shore power. 
     The heat exchanger  20  further includes a thermostat wire  22  which is routed from a thermostat switch  25  to the pump  30 , thereby starting/stopping the pump  30  relative to the temperature of the potable water within the heat exchanger  20 . After circulation and heating of the potable water by the heat exchanger  20 , the heated potable water exits the heat exchanger  20  via the outlet tube  27  which penetrates the peripheral side panel  28  in a similar manner as the inlet tube  26 . The potable water then flows through the return line  55 , through a check valve  40 , and returns to the hot water holding tank  60 . The check valve  40  provides a flow direction control means to prevent reverse flow in the return line  55 , thus preventing cross-contamination of the potable water system. 
     Referring now to  FIG. 2 , depicting an environmental view of the heat exchanger portion  20  of the apparatus  10 , there are provided a first quick coupler  41  for detachably attaching the inlet tube  26  to the supply line  50  thus forming a water supply conduit means and a second quick coupler  42  for detachably attaching the outlet tube  27  with return line  55  thus forming a water return conduit means. The quick couplers  41  and  42  are envisioned being attached thereto using conventional plumbing methods such as pipe threads, soldering, or the like. The quick couplers  41  and  42  are further envisioned to be common two-piece devices commonly used on hydraulic and pneumatic supply lines, allowing quick connection of the heat exchanger portion  20  without losing water or water pressure. 
     Referring now to  FIGS. 3   a - 3   b , close-up and bottom views of the heat exchanger portion  20  of the apparatus  10 , the enclosure of the heat exchanger portion  20  includes an aperture  33  centrally formed in a top panel  24 , an aperture  34  centrally formed in a bottom panel  21 . The heat exchanger  20  further includes a thermostat switch  25  and a thermostat wire  22 . Once potable water passes through the side panel  28  portion of the heat exchanger  20  via the inlet tube  26 , the inlet tube  26  is converted into a heating tube unit  32  using conventional copper tube sweating techniques common in the art. The heating tube unit  32  is located internal to the enclosure of the heat exchanger  20  and provides increased heating surface area via a plurality of inter-connected copper tubes forming a multi-level matrix or coil arrangement. Each aperture  33 ,  34  is envisioned being approximately six (6) inches in diameter, thereby allowing a vertical flow of heated air to pass from the burner  71  upwardly and directly to and through the heating tube unit  32 . The top panel  24  preferably has a planar exterior surface enabling the user to use the burner  71  for cooking, by placing a cooking vessel (not shown) atop of the planar exterior surface in a normal manner, at the same time as water is heated. 
     While the pump  30  can be operated manually to selectively circulate potable water through the heat exchanger  20 , the thermostat switch  25 , which is preferably disposed internal within the enclosure of the heat exchanger  20  (see  FIG. 3   a ), and a thermostat wire  22  provide automatic duty cycle control means to the pump  30  (see  FIG. 1 ). The thermostat switch  25  is envisioned to be a common temperature sensitive bi-metallic component similar to those used in clothes dryers and various major appliances. Once the potable water within the heat exchanger  20  is at a first pre-selected temperature as determined by the thermostat switch  25  and which may be manually set, the thermostat switch  25  provides a contact closure to the power circuit portion of the pump  30  via a thermostat wire  22 , thereby energizing the pump  30  and initiating circulation of the potable water through the apparatus  10 . When the thermostat switch  25  senses a second pre-selected temperature of the heated potable water, it contacts open de-energizing pump  30  and discontinuing circulation of the potable water through the apparatus  10 . 
     Referring now to  FIG. 4 , an electrical block diagram of the apparatus  10 , according to a presently preferred embodiment of the invention, is illustrated. As shown there is a simple 12-volt DC switching circuit showing current from an existing watercraft 12-volt DC circuit being supplied to the apparatus  10  via a standard 12-volt plug  31  to the normally open bi-metallic thermostat switch  25  which provides a contact closure to the power circuit portion of a pump  30 . As was noted above, when the potable water is heated, the thermostat switch  25  contacts close and open, thereby energizing and de-energizing the pump  30  via the thermostat wire  22  and enabling automatic operation of the apparatus  10 . 
     The presently preferred embodiment of the invention can be installed onto an existing recreational marine watercraft (not shown) by a qualified marine plumber as indicated in  FIGS. 1-2 . Once installed, the apparatus  10  may be utilized by a common user in a simple and effortless manner with little or no training. 
     The method of installing and utilizing the apparatus  10  may be achieved by performing the following steps: positioning the heat exchanger assembly  20  complete with pre-installed thermostat switch  25 , inlet  26  and outlet  27  tubes and quick couplers  41 ,  42  on top of the burner  71  of the watercraft stove  70 ; installing and mounting the pump  30 , check valve  40 , preferably within a closet or other discreet location aboard a watercraft being in proximity to an existing stove  70 ; routing and connecting the supply and return lines  50 ,  55  to an existing potable water holding tank  60  using common marine plumbing practices; routing and connecting the remaining supply and return lines  50 ,  55  to the quick couplers  41 ,  42 ; plugging the 12-volt plug  31  into an available 12-volt receptacle; turning on the burner  71 ; initiating the pump  30  automatically via the thermostat switch  25  and thermostat wire  22  as the potable water within the heat exchanger  20  reaches a preset temperature; continuing to operate the apparatus  10  in an automatic state as needed; utilizing heat from the burner  71  by placing a cooking vessel upon the top panel  24  of the apparatus  10 ; disabling the apparatus  10  by unplugging the 12-volt plug  31 ; removing the heat exchanger portion  20  by disconnecting the quick couplers  41 ,  42 ; removing and storing the heat exchanger  20 ; utilizing the burner  71  as intended by placing a cooking vessel thereupon the stove  70 ; and, benefiting from the ability to maintain a source of potable hot water upon one&#39;s watercraft (not shown) while away from AC shore power or while the watercraft engine (not shown) is turned off. 
     Thus, the present invention has been described in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use the same. It will be understood that variations, modifications, equivalents and substitutions for components of the specifically described embodiments of the invention may be made by those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims. 
     The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention and method of use to the precise forms disclosed. Obviously many modifications and variations are possible in light of the above teaching. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application, and to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions or substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but is intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.