Abstract:
An electrolytic generator for producing hydrogen and oxygen switches polarities of electrodes to minimize the accumulation of electroplated electrode material driven from one electrode to the other. The generator contains two or more electrolytic cells in a lower portion, with an upper portion, including gas receiving receptacles. Preferably, water extends upward past a division between the upper and lower portions. In a first version, the upper portion, which is attached for gas collection through flexible hoses, is moved from one cell in the lower portion to another when the polarity is switched. In a second version, the upper portion remains stationary while the lower portion is moved to another upper portion as the polarity is switched.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to apparatus for the generation of hydrogen and oxygen by the electrolysis of water.  
         [0003]     2. Summary of the Background Art  
         [0004]     Conventional apparatus for generating hydrogen and oxygen by the electrolysis of water includes at least one anodic cell, and at least one cathodic cell, with the cells being filled with a common electrolyte, including water and a salt making the water electrically conductive. An electrical current is driven through the electrolyte between a positive electrode, or anode, within the anodic cell(s) and a negative electrode, or cathode, causing the water molecules to dissociate into positive hydrogen ions, which are driven to form hydrogen bubbles at the cathode(s), and into negative oxygen ions, which are driven to form oxygen bubbles at the anode(s).  
         [0005]     One problem associated with the operation of such apparatus arises from a tendency of metals used to form the anode(s) to form ions that are electrodeposited on the cathode(s), depleting material from the anode(s) and causing a possibly uneven and undesirable growth of material on the cathode(s). What is needed is a way to minimize this effect.  
         [0006]     U.S. Pat. Nos. 5,846,390 and 6,846,394 each describe apparatus for generating alkaline and acidic water by means of electrolysis, with the electrode polarity being switched to clean an accumulation of a scale composed of materials such as calcium carbonate, calcium hydroxide, and magnesium hydroxide, which forms on the electrode at which alkaline water is accumulated. In the device of U.S. Pat. No. 5,846,390, a cleaning cycle occurs at a time when the water is not being used, with water generated during the cleaning process being drained away. In the device of U.S. Pat. No. 6,846,394, the outputs of the electrolytic cells are switched when the polarities of the electrodes are switched to prevent the formation of scale at the electrode.  
         [0007]     U.S. Pat. No. 3,755,113 describes an apparatus for electrorefining nickel, in which a thick coating of nickel is electrodeposited on the cathode, with the process including switching the polarity of the cathode for 3.0 to 8.0 percent of the time, with the process resulting in a more even deposition of the nickel, apparently by reducing variations in the concentration of nickel salts in the solution adjacent the cathode.  
         [0008]     While such apparatus uses polarity switching to avoid particular problems occurring at the electrodes during continued operation at a single polarity, what is needed is such an electrolytic apparatus producing hydrogen and oxygen with polarity switching, with the mixing of hydrogen and oxygen bubbles within the anodic and cathodic cells being prevented so that an explosive gas mixture is not produced.  
         [0009]     Other references from the patent literature describe configurations for effective electrodes for use in the electrolytic production of hydrogen and oxygen. In general, such methods provide a substantial surface area in which contact occurs between the electrode and the electrolyte. For example, U.S. Pat. App. Pub. No. 2005/011765 A1 describes such electrodes as being formed from a number of spaced-apart disks that are vibrated to facilitate the movement of gas bubbles away from the disks, while U.S. Pat. No. 5,879,522 describes the use of an anode and cathode each including an electrically conductive sheet and adjacent discrete conductive ultramicroelectrode particles.  
       SUMMARY OF THE INVENTION  
       [0010]     It is a first objective of the invention to provide an apparatus for generating hydrogen and oxygen in which the polarities of the electrodes within electrolytic cells are intermittently switched to reduce the accumulated effect of plating the electrode material from one electrode to another.  
         [0011]     It is another objective of the invention to provide a means providing relative movement between the conduits receiving hydrogen and oxygen and electrolytic cells when the polarities of electrodes within the electrolytic cells are switched, so that one such conduit always receives hydrogen while the other conduit always receives oxygen.  
         [0012]     In accordance with a first aspect of the invention, apparatus is provided for generating hydrogen and oxygen by electrolysis of water. The apparatus includes a plurality of electrolytic cells, an electrolyte conduit, a circuit, switching means, an oxygen receiving conduit, and a hydrogen receiving conduits. Each of the electrolytic cells includes an electrode and a container holding a portion of an electrolytic fluid including water in contact with the electrode. The electrolyte conduit extends among the electrolytic cells, holding a portion of the electrolytic fluid in communication with the electrolytic fluid within each of the electrolytic cells. The circuit causes electrical current to flow through positive and negative terminals connected to the electrodes and through the electrolytic fluid within the electrolytic cells and within the conduit during production cycles. The switching means operates during switching cycles occurring between production cycles, in which hydrogen and oxygen is produced, to cause each electrode within the plurality of electrolytic cells to be electrically connected alternately to the positive and negative terminals of the circuit during production cycles. The hydrogen receiving conduit is connected to each electrolytic cell having an electrode electrically connected to the negative terminal of the circuit; while the oxygen receiving conduit is connected to each electrolytic cell having an electrode electrically connected to the positive terminal of the circuit.  
         [0013]     Preferably, the apparatus additionally includes an interface plate extending between adjacent electrolytic cells, each of which includes a cell opening extending through the interface plate, with the hydrogen receiving conduit and the oxygen receiving conduit each including conduit opening tubes extending away from the interface plate and moving along the interface plate between adjacent cell openings during switching cycles. Preferably, each of the electrolytic cells extends downward from one of the cell openings, with the conduit opening tubes extending upward from the interface plate, and with a level of the electrolytic fluid being held within the conduit opening tubes above each of the cell openings. The cell openings are preferably spaced apart in a circular pattern within the interface plate, with the switching cycle including relative rotation between the interface plate and the conduit opening tubes about a center of the circular pattern.  
         [0014]     In a first version of the invention, the electrolytic cells remain stationary, while the hydrogen receiving conduit and the oxygen receiving conduit, each of which include a flexible portion, move between the cells. Preferably, the cell openings are equally spaced in the circular pattern in the interface plate, with the conduit opening tubes of the hydrogen receiving conduit being disposed in a circular pattern alternating with the conduit openings of the oxygen receiving conduit, and with the conduit openings being moved between adjacent cell openings in alternate directions during alternate switching cycles.  
         [0015]     In a second version of the invention, the oxygen receiving conduit and the hydrogen receiving conduit remain stationary, with the electrolytic cells being moved between the hydrogen receiving conduit and the oxygen receiving conduit.  
         [0016]     The apparatus may additionally include an overflow tube, connected to the electrolyte conduit, extending upward to an overflow edge from which the electrolytic fluid overflows to maintain a prescribed level within each of the conduit opening tubes. A fluid level switch, operating when the electrolytic fluid within the overflow tube falls below a predetermined level, causes a valve to opening, so that additional electrolytic fluid to enter the electrolytic cells. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0017]      FIG. 1  is a plan view of apparatus for generating hydrogen and oxygen by electrolysis, built in accordance with the invention for producing hydrogen and oxygen by the electrolysis;  
         [0018]      FIG. 2  is a cross-sectional elevation of the apparatus of  FIG. 1 , taken as indicated by section lines  2 - 2  therein to show electrolytic cells thereof;  
         [0019]      FIG. 3  is a schematic view of devices controlling operation of the apparatus of  FIG. 1 ;  
         [0020]      FIG. 4  is a fragmentary plan view of an interface plate within the apparatus of  FIG. 1 , showing slots providing for water flow therein;  
         [0021]      FIG. 5  is a fragmentary cross-sectional elevation of the apparatus of  FIG. 1 , taken as indicated by section lines  5 - 5  therein to show a mechanism for maintaining a level of the electrolyte thereof.  
         [0022]      FIG. 6  is a fragmentary cross-sectional elevation of the apparatus of  FIG. 1 , taken as indicated by section lines  6 - 6  therein to show a motor drive thereof; and  
         [0023]      FIG. 7  is a cross-sectional elevation of an alternative apparatus for generating hydrogen and oxygen, built in accordance with the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]     The invention will first be described with reference being made to  FIGS. 1 and 2 .  FIG. 1  is a plan view of apparatus  10  for generating hydrogen and oxygen by electrolysis of water, and  FIG. 2  is a cross-sectional elevation of the apparatus  10 , taken as indicated by section lines  2 - 2  in  FIG. 1  to show electrolytic cells  12  therein. The apparatus  10  includes a generator housing  14 , holding the electrolytic cells  12 , and a conduit housing  16 , to which a hydrogen receiving conduit  18 , and an oxygen receiving conduit  20  are attached. Each of the electrolytic cells  12  includes an electrode  22  and a container  24  holding a portion of an electrolytic fluid  26 , including water, in contact with the electrode  22 . A housing base  27  of the generator housing  14  additionally includes an electrolyte channel  28 , extending among the various electrolytic cells  22  to hold a portion of the electrolytic fluid  26  in communication with each of the electrolytic cells  12  through a lower opening  30  in the bottom of the cell  12 . The generator housing  14  also includes an interface plate  32  extending among the electrolytic cells  12 , each of which includes a cell opening  34  within the interface plate  32 . The hydrogen receiving conduit  18  and the oxygen receiving conduit  20  each include a number of conduit opening tubes  36  individually aligned with the various cell openings  34 . For example, each of the electrodes  22  includes a number of radially tapered metallic disks  37  clamped together in electrical contact with a current-carrying wire  38 .  
         [0025]      FIG. 3  is a schematic view of devices controlling operation of the apparatus  10 . During production cycles of the apparatus  10  to produce hydrogen and oxygen, the electrodes  22  are electrically connected to a power supply  39  by means of a switching circuit  40 , with certain of the electrodes  22  being connected to a positive terminal  42  of the power supply  39  to form anodes, and with the remaining electrodes  22  being connected to a negative terminal  44  of the power supply  39  to form cathodes. The power supply  39  is a device connected to a power line or to another source of electrical energy, such as a solar panel.  
         [0026]     With the flow of current through the electrolytic fluid  26 , oxygen is formed at the electrodes  22  that are electrically connected as anodes, with oxygen bubbles moving upward from the surfaces of such electrodes  22  to release a gas collected by the oxygen receiving conduit  20 . Similarly, hydrogen is formed at the electrodes  22  that are electrically connected as cathodes, with hydrogen bubbles moving upward from the surfaces of such electrodes  22  to release a gas connected by the hydrogen receiving conduit  18 .  
         [0027]     The apparatus  10  is additionally provided with means for establishing a flow of the electrolyte  26  within the apparatus  10  and for replenishing the electrolyte  26  as the water it contains is converted into hydrogen and oxygen. The electrolyte  26  is added through an electrolyte supply tube  46 , which empties the electrolyte into a central reservoir tube  48 , extending upward with a central housing column  50  from an reservoir channel  52  within the housing base  27  of the generator housing  14 . The reservoir channel  52  is in tern connected by a number of holes  54  within the housing base  27  to an inner annular space  56  extending between the container  24  of each of the electrolytic cells  22  and an intermediate cylinder  58  extending around the container  24 . The container  24  includes a number of holes  50 . permitting a flow of the electrolytic fluid  26  between the inner annular space  56  and the space  62  within the container  24 .  
         [0028]      FIG. 4  is a fragmentary plan view of the interface plate  32 , showing a number of slots  64  within the upper surface  66  of the plate  32 , providing for a flow of the electrolyte fluid  26  outward from the space  62  within the container  24 . Referring to  FIGS. 2 and 4 , fluid flowing through the slots  64  moves downward through holes  68  within the interface plate  32  and through an outer annular space  70  between the intermediate cylinder  58  and an outer cylinder  70 .  
         [0029]      FIG. 5  is a fragmentary cross-sectional elevation of the apparatus  10 , taken as indicated by section lines  5 - 5  in  FIG. 1  to show the means used to maintain a predetermined level of the electrolytic fluid  26  within the apparatus  10 . Both a float-operated switch  72  and an overflow edge  74  are used within a level control column  76  for this purpose. Referring to  FIGS. 2 and 5 , the electrolyte channel  28  within the housing base  27  is connected to an overflow tube  78  within the level control column  76 , with the level control tube  78  extending upward to the overflow edge  74 , so that the level of electrolytic fluid  26  within the tube  78  is limited to the level of the overflow edge  74 , so that excess fluid flowing down an annular space  80  within the level control column  76  is drained away through a drain hose  82 .  
         [0030]     A float  84  slidably mounted within the level control tube  78  actuates the float-operated switch  72  when the level of the electrolytic fluid  26  falls to an offset distance below the overflow edge  74 . Referring again to  FIGS. 2 and 3 , when the switch  72  is actuated in this way, the switching circuit  40  opens a solenoid valve  86  to begin a flow of electrolytic fluid into the apparatus  10  through the electrolyte supply tube, with the solenoid valve  86  then being held open long enough to raise the level of the electrolytic fluid  26  a sufficient amount to allow some of the fluid to spill over the overflow ledge  74 .  
         [0031]     In accordance with the invention, the conduit housing  16  and the generator housing  14  are movable relative to one another, with movement between these housings  14 ,  16  being used along with switching the electrical polarities of the electrodes  22  to maintain alignment between the conduit opening tubes  36  of the hydrogen receiving conduit  18  with the cell openings  34  of electrolytic cells  12  having electrodes  22  functioning as cathodes, and to maintain alignment between the conduit opening tubes  36  of the oxygen receiving conduit  20  with the cell openings  34  of the electrolytic cells  12  having electrodes  22  functioning as anodes.  
         [0032]     In the example of  FIGS. 1 and 3 , the generator housing  14  remains stationary while the conduit housing  16  rotates about a central shaft  88  forming a portion of the central housing column  50 . The conduit housing  16  includes a bushing  90  that turns on the central shaft  88 , with the bushing  90  extending between an interface plate  94  and a top plate  96 . The interface plate  94  of the conduit housing  16  turns on the interface plate  32  of the generator housing  14 , with the interface plates  94 ,  32  being held together by a spring washer  98  clamped on the top plate  96  by a thrust collar  100  attached to the central housing column  50 . The interface plates  94 ,  32  preferably include a number of sealing elements  101 , such as O-rings, that prevent a leakage of the electrolytic fluid  26  while the interface plate  94  and is held stationary and additionally while it is being moved.  
         [0033]     Preferably, the cell openings  34  are equally spaced in a circular pattern in the interface plate  32 , with the conduit opening tubes  36  of the hydrogen receiving conduit  18  being disposed in a circular pattern alternating with the conduit opening tubes  36  of the oxygen receiving conduit  20 , and with the conduit openings  18  being moved between adjacent cell openings in alternate directions during alternate switching cycles. Such switching cycles occur between production cycles, in which hydrogen and oxygen is produced within the apparatus  10 .  
         [0034]     The hydrogen receiving conduit  18  and the oxygen receiving conduit  20  each include a pair of conduit receptacles  102  extending upward from the conduit opening tubes  36 , which extend between the interface plate  94  and the top plate  96  for attachment to a flexible conduit portion  104  that deflects with rotation of the conduit housing  16 . As shown in  FIG. 1 , the hydrogen receiving conduit  18  and the oxygen receiving conduit  20  each include a pair of conduit receptacles  102  that are diametrically opposed to one another, with the conduit receptacles  102  of the hydrogen receiving conduit  18  being disposed at right angles from the conduit receptacles  102  of the oxygen receiving conduit  20 . Thus, rotating the conduit housing  16  through a 90-degree angle about the central shaft  88  moves the conduit receptacles  102  to adjacent electrolytic cells  12  (shown in  FIG. 2 ), with the conduit receptacles  102  that were placed over electrolytic cells  12  formerly used to produce hydrogen being placed over electrolytic cells  12  that were formerly used to produce oxygen, and with the conduit receptacles  102  that were placed over electrolytic cells  12  that were formerly used to produce oxygen being placed over electrolytic cells  12  that were formerly used to produce hydrogen. Such rotation is accompanied by using the switching circuit  40  to switch the polarities of the electrodes  22  within the electrolytic cells  12 , so that the conduit receptacles  102  of the hydrogen receiving conduit  18  are placed over a cell  12  that will produce hydrogen, and so that the conduit receptacles  102  of the oxygen receiving conduit  20  are placed over a cell  12  that will produce oxygen.  
         [0035]     While only part of the hydrogen receiving conduit  18  is shown in the drawings, the flexible conduit portions  104  of this conduit  18  are understood to be joined in a single hydrogen receiving structure to form the hydrogen receiving conduit  18 . Similarly, while only part of the oxygen receiving conduit  20  is shown, the flexible conduit portions  104  of this conduit  20  are understood to be joined in a single oxygen receiving structure to form the oxygen receiving conduit  20 .  
         [0036]     Preferably, such rotational movement occurs in alternating directions, with the conduit housing  16  being rotated through a 90-degree angle in a first direction, with the apparatus  10  then being used to produce hydrogen and oxygen for a time, and with the conduit housing then being rotated through a 90-degree angle in a direction opposite the first direction. In this way, the flexible conduit portions  104  are required to undergo only the deflections associated with 90 degrees of rotation of the conduit housing  16 .  
         [0037]      FIG. 6  is a fragmentary cross-sectional elevation of the apparatus  10 , taken as indicated by section lines  6 - 6  in  FIG. 1  to show a motor drive  106  used to effect rotation of the conduit housing  18  about the central pivot shaft  88 . The motor drive  106  includes a motor  108 , driving a pulley  110  through a gear speed reducer  112 , and a drive belt  114  engaging a grooved periphery  116  in the interface plate  94  of the conduit housing  16 . Preferably, the motor drive  106  is attached to a drive support bracket  118  of the generator housing  14  by means of an adjustable mounting bracket  120  providing for adjustment of the location of the motor  108  to achieve a proper tensioning force within the drive belt  114 . The motor  108  is preferably a type providing rotation in either direction, such as a permanent magnet motor that is reversed by reversing the polarity of the current with which it is driven.  
         [0038]     Referring to  FIGS. 1, 3 , and  6 , the apparatus  10  also includes a pair of limit switches  122 , actuated with rotational movement of the conduit housing  18  by a switch actuating bracket  124  extending outward from the interface plate  94  of the conduit housing  16  above the drive belt  114 . The limit switches  122  are arranged to be actuated at each end of a ninety-degree rotation of the conduit housing  16 . Thus, the switching circuit  40  rotates the conduit housing  18  in a first direction by driving current through the motor  108  until the limit switch  122  actuated by movement in the desired direction is actuated. When this limit switch  122  is actuated, the motor  108  is stopped. This rotational movement of the conduit housing  18  is accompanied by switching the polarity of the electrodes  22  within the electrolytic cells  12 . After operation of the apparatus  10  for a time to produce hydrogen and oxygen, the conduit housing is rotated opposite the first direction until the other limit switch  122  is actuated.  
         [0039]     As shown in  FIG. 2 , the electrolytic fluid  26  is held at a level within the conduit opening tubes  36  above the interface  124  between the conduit housing  18  and the generator housing  14 , which is formed at the cell openings  34  and between the interface plates  32 ,  94 . This is done so that a portion of the electrolytic fluid  26  moves with the conduit housing  16  when it is rotated, sealing the electrolytic fluid  26  held within the electrolytic cells  12  from the space  126  in which hydrogen or oxygen is collected above the electrolytic fluid  26  within the conduit receptacles  102 . Preferably, before the conduit housing  18  is rotated, the electrical current flowing to the electrodes  22  is turned off, stopping the production of hydrogen and oxygen, with this current additionally being left off long enough for bubbles to clear the electrolytic fluid  26  within the electrolytic cells  12 . While such a requirement may add substantially to the time required to switch the cell polarities, the production capability of the apparatus  10  should not be greatly affected, since the frequency of changing cell polarities is not great.  
         [0040]      FIG. 7  is a cross-sectional elevation of an alternative apparatus  130  built in accordance with the invention for producing hydrogen and oxygen. The alternative apparatus  130  is similar in construction and operation to the apparatus  10 , which has been described above in reference to  FIGS. 1-6 , except for the fact that the receptacle housing  132  remains stationary while the generator housing  134  turns when the polarity of the electrodes  136  within electrolytic cells  138  is changed, and additionally for the fact that the path provided for flowing electrolytic fluid  140  through the electrolytic cells  138  is somewhat different.  
         [0041]     The alternative apparatus  130  rests upon a base  142 , which provides an upward-extending central column  144  to which a top plate  146  of the receptacle housing  132  is rigidly attached. The central column  144  additionally includes bearing surfaces  148  upon which an interface plate  150  and a lower structure  152  of the generator housing  134  are rotatably of mounted. The interface plate  150  includes a groove  154  for providing rotational movement to the generator housing  134  through a drive belt  156 . In turn, the drive belt  156  is driven by a motor attached, as described above in reference to  FIG. 6 , to a bracket (not shown) extending between stationary elements, such as the receptacle housing  132  and the base  142 .  
         [0042]     Each of the electrodes  135  is attached to a contact spring  158 , providing electrical contact with a contact plate  160  attached to the base  142 . Since both the receptacle housing  132  and the base  142  remain stationary, a positive voltage is applied to the contact plates  160  directly beneath the conduit receptacles  162  receiving oxygen within the receptacle housing  132 , while a negative voltage, relative to the positive voltage, is applied to the contact plate  160  directly below the conduit receptacles  162  receiving hydrogen within the receptacle housing  132 . While the polarity of an individual electrodes  135  is switched by its movement between adjacent contact plates  160  having different polarities, the flow of current through all of the electrodes  135  may be interrupted before the rotational movement of the generator housing  132  and resumed after the completion of this rotational movement, with time being provided for bubbles of hydrogen and oxygen to leave the electrolytic fluid  140  within the electrolytic cells  138  before the rotational movement. An upward force, acting upon the generator housing  132  due to the deflection of the contact springs  158 , holds sealing elements  160  within the interface plate  150  of the generator housing  134  in contact with an interface plate  164  of the receptacle housing  132 , while sealing elements  165  of the interface plate  164  are held against the interface plate  150 , preventing leakage of the electrolytic fluid  140  between the interface plates  150 ,  164 . Additional structural elements of the generator housing  134  include, for example, a cylinder  166  extending between the lower structure  152  and the interface plate  150  and a number of tensioning rods  167 .  
         [0043]     Within the alternative apparatus  130 , electrolytic fluid  140  is provided through a central supply hose  168  to central supply tube  170  within the central column  144 , which additionally includes a number of holes  172  extending radially to connect the central supply tube  170  with an annular supply reservoir  174  within the lower structure  152  of the generator housing  134 . This annular supply reservoir  172  is in turn connected to the space  176  within each of the electrolytic cells  138  through a hole  178  at the bottom of the cell  138 . A number of slots  180  and holes  182  disposed within the interface plate  150  in the manner described above in reference to  FIG. 4 , connect the space  176  within the electrolytic cell  138  with an annular space  184  surrounding the cell  138 . This annular space  184  is connected with an annular drain reservoir  186  through one or more holes  188  provided for each electrolytic cell  138 . The central column  144  additionally includes a number of holes  190  extending radially to connect the annular drain reservoir  186  with a central drain tube  192  within the central column  144 . This central drain tube  192  is in turn connected by a radially extending drain tube  194  to a mechanism (not shown) configured generally as described above in reference to  FIG. 6 , for maintaining the level of the electrolytic fluid  140  within the alternative apparatus  130 .  
         [0044]     While the invention has been described in its preferred forms or embodiments with some degree of particularity, it is understood that this description has been given only by way of example, and that many variations can be made without departing from the spirit and scope of the invention, as defined in the appended claims.