Abstract:
A tankless water heating assembly that heats water on a continuous basis as it passes from a conventional water source and through a heating system. It basically includes a housing assembly, a plumbing assembly, a heating system, and an electrical system. The tankless water heater assembly heats water in a real time basis, as is being used, resulting in an efficient method of hot water utilization. The heating system comprises heating elements that are submerged within water as the water passes continuously through the heating units to prevent heating unit burnout, and the electrical system has means to properly measure water temperature as it is flowing within the heating system.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to water heating systems, and more particularly, to tankless water heating assemblies. 
     2. Description of the Related Art 
     The most commonly used water heaters utilize a rather large storage tank for water with intrinsic inefficiency due to the fact that the water maintain within such storage tank is effectively reheated even when the water is not being utilize on a regular basis. 
     To the contrary, an existing alternative to such storage tank water heater is a continuous flow or “tankless” water heater, wherein water is almost instantaneously heated as it passes through the continuous flow system. Prior art teaches tankless water heater assemblies for the purpose of only heating water, which is currently being used. 
     However, such prior art continuous flow water heaters are recognized as being unreliable because they often require replacement of heating units. To a large extent, this is caused by the inability to keep the plurality of individual heating elements submerged within water as the water passes continuously through the heating units to prevent heating unit burnout. In addition, such prior art continuous flow water heaters are also recognized as being unreliable because of a lack of structural integrity of the plumbing assembly as it is fitted onto the housing assembly. Furthermore, such prior art continuous flow water heaters are also recognized as being unreliable because they often improperly measure the temperature of the water as it is flowing within the heating system. 
     Applicant believes that the only reference corresponds to Applicant&#39;s own U.S. Pat. No. 5,408,578, issued on Apr. 18, 1995 for a tankless water heater assembly. However, it differs from the present invention, because in that patent Applicant taught a tankless water heater assembly, specifically adapted to heat water on a continuous basis as it passes from a conventional water source, into a heat transferring chamber, or chambers, containing immersible high power electrical heating elements. 
     Other patents describing the closest subject matter provide for a number of more or less complicated features that fail to solve the problem in an efficient and economical way. None of these patents suggest the novel features of the present invention. 
     SUMMARY OF THE INVENTION 
     The instant invention is specifically adapted to heat water on a continuous basis as it passes from a conventional water source and through a heating system. 
     More specifically, the instant invention is a tankless water heater assembly designed to heat a continuous supply of water, comprising a housing assembly. A plumbing assembly comprises at least a cold-water inlet and a hot-water outlet. A heating system comprises at least first and second heating units that house first and second heating elements respectively. The first and second heating units each have a top end and a bottom end. The first and second heating units are connected to each other by at least one bypass and at least one pipe. The bypass is positioned at or below the top ends, and the pipe is positioned below the bypass. In this configuration, air entering from the cold-water inlet or the hot-water outlet, is expelled via the bypass. Thus, keeping the first and second heating elements continuously submerged within water. The instant invention also comprises an electrical system. 
     The electrical system comprises a thermistor assembly having a heat sensing thermistor located at the pipe, in between the first and second heating units. The thermistor assembly has sending means to send a signal to regulate an amount of power delivered to the first and second heating elements under diverse water flow conditions. The housing assembly comprises a rear panel, first and second lateral panels, and a base panel. The cold-water inlet has a first threaded fitting and the hot-water outlet has a second threaded fitting. The cold-water inlet and the hot-water outlet are fitted onto the housing assembly. The cold-water inlet has first and second plates that are mounted onto each side of the first lateral panel, and the hot-water outlet has third and fourth plates that are mounted onto each side of the second lateral panel. The plumbing assembly further comprises a flow switch assembly, and the electrical system comprises a thermostat assembly. The thermostat assembly comprises thermal connection means. The thermal connection means provides heat transfer functionality. 
     It is therefore one of the main objects of the present invention to provide a tankless water heater assembly that is compact. 
     It is another object of the present invention to provide a tankless water heater assembly that heats water in a real time basis, as is being used, resulting in an efficient method of hot water utilization. 
     It is another object of the present invention to provide a tankless water heater assembly having heating elements submerged within water as the water passes continuously through the heating units to prevent heating unit burnout. 
     It is another object of the present invention to provide a tankless water heater assembly that comprises better structural integrity of the plumbing assembly as it is fitted onto the housing assembly. 
     It is another object of the present invention to provide a tankless water heater assembly that properly measures the temperature of the water as it is flowing within the heating system. 
     It is another object of the present invention to provide a tankless water heater assembly that provides satisfactory continuous flow requirements for domestic and commercial use. 
     It still is another object of this invention to provide such a device that is inexpensive to manufacture and maintain while retaining its effectiveness. 
     Further objects of the invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       With the above and other related objects in view, the invention consists in the details of construction and combination of parts as will be more fully understood from the following description, when read in conjunction with the accompanying drawings in which: 
         FIG. 1  represents an isometric view of the present invention partially housed within its housing assembly. 
         FIG. 2  is a front elevational view of the present invention, which has been partially cross-sectioned to illustrate the water level and path of water flow through various components. 
         FIG. 3  is a top plan view of the present invention, which has been partially cross-sectioned to illustrate the path of water flow through various components. 
         FIG. 4  is a cross-section view taken along line  4 - 4  from  FIG. 1 , showing the thermistor. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, the present invention is generally referred to with numeral  10 . It can be observed that it basically includes housing assembly  20 , plumbing assembly  40 , heating system  120 , and electrical system  170 . 
     As seen in  FIG. 1 , present invention  10  is directed to a continuous flow water heater and includes an outer casing or housing assembly  20  that surrounds components shown and to be described in greater detail hereinafter. Housing assembly  20  comprises rear panel  22 , lateral panels  24  and  26 , and base  28 . Although not illustrated, it is noted that housing  20  may include an outer door or cover, which may be opened or removed to facilitate minimal access to the components and to effect at least minimal repairs. However, it should be emphasized that the structure and integrity of the components of the present invention minimizes the necessity for entering into the “guts” of the subject invention to accomplish major repairs. 
     As illustrated in  FIGS. 1 and 2 , plumbing assembly  40  comprises threaded fitting  42 , defining a cold-water inlet that is connected to a conventional source of water such as the city or municipal water supply. Threaded fitting  42  includes filtering element  44  in order to eliminate any debris from entering into instant invention  10  as best possible. Plates  46  and  52  are mounted onto pipe  50 , and on each side of lateral panel  24 , to provide better structural integrity for plumbing assembly  40  as it is fitted onto housing assembly  20 . It is noted that pipe  50  extends from heating unit  124  and terminates at threaded fitting  42 . 
     Similarly, plumbing assembly  40  also comprises threaded fitting  98 , defining a hot-water outlet that is connected to additional plumbing for a domestic or commercial structure. Threaded fitting  98  includes filtering element  96  in order to eliminate any debris from exiting instant invention  10  as best possible. Plates  94  and  100  are mounted onto pipe  90 , and on each side of lateral panel  26 , to provide better structural integrity for plumbing assembly  40  as it is fitted onto housing assembly  20 . It is noted that pipe  90  extends from heating unit  130  and terminates at threaded fitting  98 . 
     Furthermore, as defined above, plumbing assembly  40  defines an improved and more reliable method of water pipe connection, whereby threaded fittings  42  and  98 , for both the cold-water inlet and the hot-water outlet respectively, are fully integrated onto housing assembly  20 , providing better structural integrity without requiring fittings as separate attachments to the housing assembly  20  that require soldering in a production process. Plumbing assembly  40  reduces water leaks, resulting in a dramatic improvement in quality and reliability. 
     Pipe  50  partially contains flow switch assembly  60 . Interior to pipe  50 , flow switch assembly  60  comprises flow switch  62  comprising magnet  64  mounted onto spring  66 . Flow switch  62  moves in a direction indicated by the numerous directional arrows, defined as water flow WF, indicating a positive path of water flow as it enters through the cold-water inlet, and exits through the hot-water outlet. Flow switch assembly  60  also comprises housing  68  that is mounted onto pipe  50 . Housing  68  comprises contacts  70  and  72 . Cables  74  extend from contacts  70  and  72  to block  236 . 
     Electrical system  170  comprises conduit  172  having electrical wiring  174  that originate from an electrical power source. Electrical wiring  174  connects to terminal block  180 , and electrical wiring  182  connects from terminal block  180  to control electronic board  186  having control knob  188 . Electrical wiring  190  also extends from control electronic board  186  to thermistor assembly  200 . Thermistor assembly  200  comprises lead  202  that inserts into cover  204 . Cables  184  also extend from terminal block  180  to thermostat block  224  of thermostat assembly  220 . Cable  226  extends from thermostat block  224  to block  234  of element terminal  230 , and cable  228  extends from thermostat block  224  to block  236  of element terminal  232 . Cable  238  connects block  234  to block  236 . 
     Although not illustrated, electrical system  170  further comprises a power supply voltage of approximately 6 volts DC regulated; a chip supply voltage of approximately 4.4 volts DC, which results in better regulation; and a main oscillator output level of approximately 800 millivolts at a frequency of 46.5 hertz (21.5 msec). Furthermore, inputs of all operational amplifiers that are not used within the chip are grounded, resulting in a better signal to noise ratio and a more precise control of the temperature of the water. Values of gate resistors of SCR&#39;s are also optimized to establish SCR conduction at a “zero crossing” point. In addition, control electronic board  186  has cooperative dimensions to allow easier access to the high voltage terminals, and power rating of a voltage-lowering resistor is approximately 7 W. 
     Thermostat assembly  220  comprises thermostat  240 . Thermostat  240  is a single protective thermostat. In the preferred embodiment, plate  222 , is a central metal plate that thermally connects heating units  124  and  130 . The thermal connection provides a heat transfer functionality required by thermostat  240 , defining thermal connection means. This feature results in fewer false “safety disconnects”, and a more reliable operation of instant invention  10 . 
     As best seen in  FIGS. 2 and 3 , heating system  120  comprises heating units  124  and  130  that are connected to each other by pipe  128  and bypass  136 . Heating unit  124  houses heating element  126  and heating unit  130  houses heating element  132 . In the preferred embodiment, pipe  128  is approximately 0.20 inches in diameter. Pipe  128  provides for equal water-pressure within heating units  124  and  130  and keeps them submerged below water level WL, even when the water source has been closed to instant invention  10 . This feature provides protection for heating elements  126  and  132  from overheating, since water is always present within heating units  124  and  130 , thus improving the reliability and safety of instant invention  10  and extending the life of heating elements  126  and  132 . 
     As best seen in  FIG. 4 , thermistor assembly  200  also comprises thermistor  206  that protrudes from lead  202  and more specifically cover  204 . Thermistor  206  is a heat sensing thermistor, located at pipe  128  between the heating units  124  and  130  to provide for a better and faster control of the water temperature. Thermistor  206  is inserted into a small opening of pipe  128 , and sends a signal, via electrical wiring  190 , to control electronic board  186  that regulates the amount of power delivered to the heating elements  126  and  132  under diverse water flow conditions, defining sending means. 
     In operation, instant invention  10  comprises sufficient water to reach water level WL, as seen in  FIG. 2 . Water flow WF, indicating a positive path of water flow, enters through the cold-water inlet and travels through pipe  50  and primarily through heating unit  124 , through pipe  128 , through heating unit  130 , and exits through the hot-water outlet. However, a small amount of water flow WF also travels through bypass  136 . When this occurs, any and all trapped air at the uppermost ends of heating units  124  and  130  is expelled via bypass  136 . In addition, water originating from the cold-water inlet may also comprise air that becomes trapped air at the uppermost ends of heating units  124  and  130 , and it too is expelled via bypass  136 . Bypass  136  allows heating elements  126  and  132  to always be submerged within the water as water flow WF travels continuously through heating units  124  and  130  of heating system  120  to prevent heating unit burnout. 
     It is emphasized that a siphoning effect is caused when water from the cold-water inlet or the hot-water outlet is turned off, or when a pipe breaks, defining back flow WF′, seen in  FIGS. 2 and 3 . In the present invention, water flow WF′ only travels through bypass  136 , and not through heating units  124  and  130 , to keep heating elements  126  and  132  submerged within the water. Without bypass  136  of the instant invention, back flow WF′ would cause water to be sucked out of heating units  124  and  130  by vacuum pressure. Such back flow WF′ would expose heating elements  126  and  132 , since they would not be submerged within water, and would cause heating units  124  and  130  to burnout if the tankless water heater assembly  10  is dry started if there is an air bubble coming into it due to a rupture in the cold-water inlet or an interruption of water flow WF. 
     The foregoing description conveys the best understanding of the objectives and advantages of the present invention. Different embodiments may be made of the inventive concept of this invention. It is to be understood that all matter disclosed herein is to be interpreted merely as illustrative, and not in a limiting sense.