Abstract:
An electrode water heater/steam generator is provided. The electrode water heater/steam generator comprises a housing for containing water therein. The housing has at least an opening for transmission of water therethrough. At least two electrodes are disposed inside the housing and secured thereto such that at least one of the electrodes is enabled to vibrate during provision of AC electrical power. Electrical circuitry connects at least one of the electrodes to a live wire of an AC electrical power supply and at least another of the electrodes to a neutral wire of the AC electrical power supply.

Description:
[0001]    The present invention relates to electric water heaters and steam generators, and more particularly to an electrode water heater/electrode steam generator that provides hot water or steam at a substantially high speed and efficiency. 
       BACKGROUND 
       [0002]    The most common form of electric hot water heating systems involves a storage tank in which water is heated to a predetermined temperature. The water in the storage tank is maintained at the predetermined temperature as water is drawn from the storage tank and replenished with cold inlet water. Electric hot water storage systems are generally considered to be energy inefficient as they operate on the principle of storing the water heated to a predetermined temperature greater than the temperature required for usage, even though the consumer may not require hot water until some future time. As thermal energy is lost from the hot water in the storage tank, further consumption of electrical energy is required to reheat that water to the predetermined temperature. 
         [0003]    A more energy efficient means of heating water than storage tank systems involves the use of a tankless water heater system—also referred to as “on-demand” or “instant” water heater system—that heats water only when hot water is being used. Most prior art tankless water heater systems use resistance type electrical heating elements to heat the water. A major disadvantage of tankless water heater systems utilizing resistance type electric heating elements is that the elements themselves have substantial thermal mass and thermal resistance, substantially reducing the speed the water is heated, especially when the water flow is started from zero. 
         [0004]    The alternative to using heating elements for heating the water is to pass an electrical current through the water by passing it between two electrodes between which an AC voltage exists, known as Direct Electrical Resistance (DER) heating. Unfortunately, existing electrode water heaters are highly complex, rendering them expensive to manufacture and difficult to implement in a compact fashion. 
         [0005]    It is desirable to provide an electrode water heater/electrode steam generator that is simple and implementable in a compact fashion. 
         [0006]    It is also desirable to provide an electrode water heater/electrode steam generator that provides hot water/steam at a substantially high speed and efficiency. 
         [0007]    It is also desirable to provide an electrode water heater that provides boiling water at a substantially high speed and efficiency. 
       SUMMARY 
       [0008]    Accordingly, one object of the present invention is to provide an electrode water heater/electrode steam generator that is simple and implementable in a compact fashion. 
         [0009]    Another object of the present invention is to provide an electrode water heater/electrode steam generator that provides hot water/steam at a substantially high speed and efficiency. 
         [0010]    Another object of the present invention is to provide an electrode water heater that provides boiling water at a substantially high speed and efficiency. 
         [0011]    According to one aspect of the present invention, there is provided an electrode water heater. The electrode water heater comprises a housing for containing water therein. The housing has at least an opening for transmission of water therethrough. At least two electrodes are disposed inside the housing and secured thereto such that at least one of the electrodes is enabled to vibrate during provision of AC electrical power. Electrical circuitry connects at least one of the electrodes to a live wire of an AC electrical power supply and at least another of the electrodes to a neutral wire of the AC electrical power supply. 
         [0012]    According to one aspect of the present invention, there is provided an electrode water heater. 
         [0013]    The electrode water heater comprises a housing for containing water therein. The housing has at least an opening for transmission of water therethrough. At least two electrodes are disposed inside the housing and secured thereto such that at least one of the electrodes is enabled to vibrate during provision of AC electrical power. The electrodes comprise an inner electrode having a longitudinal axis and at least one hollow cylinder placed concentric thereto. 
         [0014]    According to one aspect of the present invention, there is provided an electrode water heater. The electrode water heater comprises a housing for containing water therein. The housing has at least an opening for transmission of water therethrough. At least two electrodes are disposed inside the housing and secured thereto such that at least one of the electrodes is enabled to vibrate during provision of AC electrical power. Electrical circuitry connects each of the electrodes to a live wire of a multiphase AC electrical power supply. 
         [0015]    One advantage of the present invention is that it provides an electrode water heater/electrode steam generator that is simple and implementable in a compact fashion. 
         [0016]    A further advantage of the present invention is that it provides an electrode water heater/electrode steam generator that provides hot water/steam at a substantially high speed and efficiency. 
         [0017]    A further advantage of the present invention is to provide an electrode water heater that provides boiling water at a substantially high speed and efficiency. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    One embodiment of the present invention is described below with reference to the accompanying drawings, in which: 
           [0019]      FIG. 1 a    is a simplified block diagram illustrating a cross sectional view of an electrode water heater according to an embodiment of the invention; 
           [0020]      FIG. 1 b    is a simplified block diagram illustrating in a detailed cross sectional view one electrode placed in a housing of the electrode water heater according to an embodiment of the invention; 
           [0021]      FIGS. 1 c  to 1 g    are simplified block diagrams illustrating a top view, a cross sectional view, a side view, a perspective top view, and a perspective bottom view of the bottom plate of the electrode water heater according to an embodiment of the invention; 
           [0022]      FIG. 2 a    is a simplified block diagram illustrating a cross sectional view of the electrode water heater according to an embodiment of the invention with water inlet and water outlet mounted thereto; 
           [0023]      FIG. 2 b    is a simplified block diagram illustrating control circuitry for operating the electrode water heater according to an embodiment of the invention; 
           [0024]      FIG. 2 c    is a simplified block diagram illustrating a side view of an instant water heater employing the electrode water heater according to an embodiment of the invention; and, 
           [0025]      FIG. 3  is a simplified block diagram illustrating a cross sectional view of a boiler type water heater employing the electrode water heater according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, certain methods and materials are now described. 
         [0027]    While the description of the embodiments hereinbelow is with reference to an instant water boiler for providing relatively small quantities of hot/boiling water/steam for human consumption in a residential household setting, it will become evident to those skilled in the art that the embodiments of the invention are not limited thereto, but are also adaptable for providing larger quantities of hot/boiling water/steam in various other applications such as, for example, heating and industrial processes. 
         [0028]    Referring to  FIGS. 1 a  to 1 g   , an electrode water heater  100  according to an embodiment of the invention is provided. The electrode water heater  100  comprises an electrically non-conductive housing, in one case, having a bottom plate  102 . 1 , a top plate  102 . 2 , and a housing ring  104 . The bottom plate  102 . 1 , the top plate  102 . 2 , and the housing ring  104  are made of a heat resistant and electrically non-conductive material, in one case, a plastic material such as, for example, Acetal using standard plastic molding techniques. Alternatively, other heat resistant and electrically non-conductive materials may be employed or the inside of the housing may be coated with a heat resistant and electrically non-conductive material. Electrodes  106 . 1 - 106 . 7  are disposed inside the housing with the electrodes  106 . 2 - 106 . 7  being provided as hollow cylinders surrounding inner electrode  106 . 1  concentrically about longitudinal axis  120 , as illustrated in  FIG. 1 a   . The electrodes  106 . 1 - 106 . 7  can be spaced equidistant apart. Upper and lower end portions of the electrodes  106 . 2 - 106 . 7  are accommodated in respective grooves  122  disposed in the bottom plate  102 . 1  and the top plate  102 . 2 . The electrodes  106 . 2 - 106 . 7  and the grooves  122  are dimensioned such that the width W G  of the grooves  122  is greater than the width W E  of the electrodes  106 . 2 - 106 . 7 , leaving gaps G 1  and G 2  therebetween, as well as the height H E  of the electrodes  106 . 2 - 106 . 7 , the inner height R H  of the housing and the depth D G  of the grooves  122  being such that there is gap G 3  between the top of the electrodes  106 . 2 - 106 . 7  and the respective grooves  122 , as illustrated in  FIG. 1 b   . Provision of the electrodes  106 . 2 - 106 . 7  and the grooves  122  as illustrated in  FIG. 1 b    holds the electrodes  106 . 2 - 106 . 7  with respect to: each other having predetermined distances therebetween; the inner electrode  106 . 1 ; and, the housing, but also the enables the electrodes  106 . 2 - 106 . 7  to vibrate in a direction along the axis  120  as well as in directions perpendicular thereto within a predetermined range—gaps G 1 , G 2 , and G 3 —as indicated by the block arrows in  FIG. 1 b   . The electrodes  106 . 1 - 106 . 7  are made of an electrically conductive material such as, for example, aluminum, stainless steel, or brass. The housing, together with the electrodes  106 , is secured using, for example, a screw bolt  116 A in concert with screw nut  116 B such that the inner electrode  106 . 1  and the housing ring  104  are abutted between the bottom plate  102 . 1  and the top plate  102 . 2 , thus enabling simple assembly of the device. The housing ring  104 , the bottom plate  102 . 1  and the top plate  102 . 2  can be in a watertight contact when secured. Optionally, a seal such as, for example, an O-ring, is disposed between the housing ring  104  and the respective housing plate  102 . 1 / 102 . 2 . Further optionally, the electrode  106 . 1  is provided as a hollow cylinder having abutting cylinder disposed inside, enabling the electrode  106 . 1  to be disposed such that the same can vibrate. 
         [0029]    The electrodes  106 . 1 - 106 . 7  are connected to insulated wiring  108 . 1  and  108 . 2  in an alternating fashion, as illustrated in  FIG. 1 a   , with the wiring  108 . 1  and  108 . 2  for being connected to a neutral wire and a live wire, respectively, of single phase AC electrical power—also known as household power—or vice versa. The wiring  108 . 1  and  108 . 2  is provided using off-the-shelf insulated wiring for household power and is connected to the respective electrodes  106 . 1 - 106 . 7  using standard fitting technology such as, for example, soldering. The connection of the wiring with the electrodes can be coated in order to prevent contact of copper wiring and solder with the water when the same is used for human consumption. The wiring  108 . 1  and  108 . 2  is sufficiently flexible to enable the electrodes  106 . 2 - 106 . 7  to vibrate as described hereinabove. For protecting a user of the heater  100  against electrical shock in case of a malfunction of the device, grounding ring  110  for being connected to ground via wiring  108 . 3  is disposed around housing ring  104 . Optionally, the grounding ring  110  is omitted, for example, when the heater  100  is disposed inside a grounded housing. 
         [0030]    Water is provided to the electrodes  106 . 1 - 106 . 7  and removed therefrom after heating via apertures  112 ,  113  disposed in the top plate  102 . 2  and the bottom plate  102 . 1 . The apertures  112 ,  113  can be placed such that the water is approximately equally distributed around the electrodes  106 . 1 - 106 . 7  and dimensioned to enable a water flow therethrough within a predetermined range. For example, in applications where the heater  100  is empty when not in use, the water flow is restricted to the extent such that a power surge is prevented when the heater  100  is started. 
         [0031]    In operation AC current is passed through the water disposed between adjacent electrodes heating the same. A large electrode surface area in contact with the water can be disposed in a relatively small volume, for example, by providing a plurality of nested electrodes such as concentric ring electrodes, as illustrated in  FIG. 1 a   . The speed of heating the water is increased by enabling the electrodes to vibrate induced by the provision of the AC electrical power. 
         [0032]    As is evident, the electrode water heater  100  is implementable employing different numbers of two or more electrodes. Furthermore, the electrodes may have other shapes than circular ring shape such as, for example, rings having oval or square cross sections, plates, half spheres. 
         [0033]    The electrode water heater  100  is designed in dependence upon the electrical conductivity of the water, the range of the water flow rate, the range of desired hot water temperatures, and the electrical power (Voltage and frequency), using standard electrical engineering methods. The electrodes can be designed such that the electrical power drawn by the device does not exceed a predetermined limit. 
         [0034]    It is noted that, while the electrode water heater  100  is described with its longitudinal axis  120  oriented substantially vertical, the same is also operable with the longitudinal axis  120  oriented substantially horizontal or at angles therebetween. 
         [0035]    Referring to  FIGS. 2 a  to 2 c   , the electrode water heater  100  has been implemented in an instant water heater  200 , illustrated in  FIG. 2 c   , for providing a relatively small quantity of hot/boiling water in a kitchen, replacing an electric kettle. The electrode water heater  100  has mounted thereto water inlet  130  for receiving water through inlet opening  130 A and water outlet  132  for providing the heated/boiling water through outlet opening  132 A, as indicated by the block arrows in  FIG. 2 a   . The water inlet  130  and the water outlet  132  are made of a heat resistant and electrically non-conductive material, in one case, a plastic material such as, for example, Acetal using standard plastic molding techniques. The water inlet  130  and the water outlet  132  are, for example, mounted to the top plate  102 . 2  and the bottom plate  102 . 1 , respectively, of the electrode water heater  100  in a water tight fashion using, for example, an adhesive. Inlet temperature sensor  140  and water flow sensor  142  can be disposed in the inlet  130  for sensing the inlet water temperature and the inlet water flow rate and for providing signals indicative thereof via wiring  140 A and  142 A, as well as outlet water temperature sensor  144  disposed in the water outlet  132  for sensing the outlet water temperature and for providing a signal indicative thereof via wiring  144 A. 
         [0036]    Referring to  FIG. 2 b   , control circuitry  150  is connected to a single phase AC electrical power source—for example, 120V and 60 Hz (North America)—via a plug mated with a standard household power outlet. The control circuitry  150  is connected: to the electrode water heater  100  via wiring  108 . 1 ,  108 . 2 ,  108 . 3  for providing electrical power thereto in a controlled fashion; the sensors  140 ,  142 , and  144  via respective wiring  140 A,  142 A, and  144 A for receiving sensor signals; and to user interface  152  for receiving user input data such as a desired water temperature. For example, the control circuitry  150  comprises a microprocessor for receiving the user input data and the sensor data and for controlling the provision of the electrical power to the electrode water heater  100  in dependence upon the user input data and the sensor data. 
         [0037]    Alternatively, the user interface  152  and the sensors  140 ,  142 , and  144  are omitted and the control circuitry  150  is employed for limiting the supply of electrical power to the electrode heater  100 , for example, to 1200 W, in order to prevent a power surge. 
         [0038]    The instant water heater  200  comprises a base plate  170  having mounted thereto a curved tube  172  made of, for example, stainless steel. A bottom end of the tube  172  comprises inlet  176  for being connected to a water supply for receiving water therefrom. A top end of the tube  172  is mounted to the electrode water heater  100  via water inlet  130 . Control housing  178  comprises the control circuitry  150  connected to the electrode water heater  100  via cable  174 —containing the wiring  108 . 1 ,  108 . 2 ,  108 . 3 ,  140 A,  142 A, and  144 A—and user interface  152 . The control housing can also comprise a solenoid valve for regulating the water flow through the tube  172  in dependence upon user input received via the user interface  152 . The user interface comprises, for example, conventional knobs that are turned for determining the water flow and the temperature or push buttons. In operation, water is received at the inlet  176  and provided to the electrode water heater via tube  172  and provided therefrom after heating via water outlet  132 A, as indicated by the block arrows in  FIG. 2 c   , into a receptacle  10  such as, for example, a pot or mug, placed onto the base plate  170 . 
         [0039]    The electrodes  106 . 1 - 106 . 7  of the electrode water heater  100  as employed in the instant water heater  200  are made of aluminum having the dimensions of: height H E  of 1.39″; width W E  of 0.031″; and outside diameters D OE  in ascending order of 0.375″, 0.938″, 1.5″; 2.063″, 2.625″, 3.188″, and 3.75″. The housing is made of Acetal having the inside dimensions of: height H IH  of 1.27″ and diameter D IH  of 4.00″. The grooves  122  have the dimensions of: depth D G  of 0.065″ and width of W G  of 0.055″. 
         [0040]    Alternatively, the electrode water heater  100  is employed in a boiler type water heater such as, for example, a kettle, as illustrated in  FIG. 3 . Here, the electrode water heater  100  is disposed in the bottom of receptacle  160  containing water  10 , replacing the resistance type electrical heating elements of a conventional kettle. 
         [0041]    Further alternatively, the electrode water heater  100  is implemented for producing steam, for example, by providing a reduced amount of water such that only a bottom portion of the electrodes  106  is submerged in the water. Optionally, an electrolyte such as, for example, baking soda, is added to the water to increase the efficiency of the steam production. 
         [0042]    Further alternatively, the electrode water heater  100  is adapted for being connected to multiphase AC electrical power. For example, the electrode water heater  100  is provided with three electrodes  106  with each electrode being connected to a live wire associated with one phase of three phase AC electrical power. In particular for generating steam, high frequency and high voltage can be used, for example, a frequency of 400 Hz and each phase having a voltage of 200V. 
         [0043]    The present invention has been described herein with regard to certain embodiments. However, it will be obvious to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as described herein.