Abstract:
The invention relates to an electrolytic cell comprising a housing having a channel extending there through; an inlet allowing water to pass into the channel; an outlet allowing water to pass from the channel; and a series of electrodes located within the channel; wherein the channel is a spiral.

Description:
CROSS REFERENCE 
       [0001]    The present application is a National Stage entry from PCT Patent Application No. PCT/AU2010/000931 filed on 22 Jul. 2010, which claims priority to Australian Application 2009903424 filed on 22 Jul. 2009 the contents of each one incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to an electrolytic cell. In particular, the invention relates to an electrolytic cell used in chlorination of salt water swimming pools, spas and the like bodies of water. 
       BACKGROUND OF THE INVENTION 
       [0003]    The chlorination of pools is necessary to prevent the unwanted growth of bacteria in the water. Electrolytic chlorination has become a popular method of achieving bacteria free water. Electrolytic chlorination uses common salt which is added to the water located within the pool in combination with an electrolytic cell which is used to produce chlorine. This chlorine is released into the water thereby killing any unwanted bacteria and micro organisms. This process is cost effective, low maintenance and environmentally friendly. 
         [0004]    When using an electrolytic cell to chlorinate pool water, a by-product of this process is the formation of hydrogen gas. Normally the hydrogen gas is transmitted with the water flowing through the electrolytic cell into the pool and dissipated into the atmosphere. However, if the pool pump ceases to operate, the electrolytic cell will continue to operate, producing hydrogen gas. Instead of the hydrogen gas flowing with the water into the pool and subsequently into the atmosphere, the hydrogen gas can continue to build up. In extreme circumstances, this can cause an explosion if the hydrogen gas is ignited. 
         [0005]    U.S. Pat. No. 4,861,451 describes an electrolytic cell which is configured to reduce the likelihood of a hydrogen explosion in an electrolytic cell. The electrolytic cell is configured so that an inlet and an outlet of the cell are located below electrodes located within the body of the electrolytic cell. If hydrogen gas does accumulate within the electrolytic cell, the hydrogen gas becomes trapped within the electrolytic cell forcing the water below the electrodes. This stops electrolyses from occurring and hence, stops the production of hydrogen gas. 
         [0006]    The electrolytic cell, shown in U.S. Pat. No. 4,861,451, is very effective in limiting the amount of hydrogen produced by the electrolytic cell. However, because of the design of the electrolytic cell, there are some inherent disadvantages. When the electrolytic cell is in a horizontal position, water must flow through four 90 degree changes of direction in order to provide a trap for the hydrogen in electrolytic cell. This detracts significantly from the hydraulic efficiency of a pool chlorination system by adding additional pressure, which is theoretically equivalent to adding six metres of pipe to the system. When the electrolytic cell is in a vertical position, a looped arrangement is required at the top of the pool chlorination system to again provide a trap for hydrogen gas. This again adds a substantial amount of additional piping. This additional piping and the changes of direction of the water flow generally require a larger pump in order to pump water effectively through the chlorination system, making the chlorination system more expensive. Further, pumping is generally more complex with the change in pipe direction. 
       OBJECT OF THE INVENTION 
       [0007]    It is an object of the invention to overcome or alleviate one or more of the disclosures or provide the consumer with the useful or commercial choice. 
       SUMMARY OF THE INVENTION 
       [0008]    In one form, although not necessary the only or broadest form, the invention relates to an electrolytic cell comprising: 
         [0009]    a housing having a channel extending there through; 
         [0010]    an inlet allowing water to pass into the channel; 
         [0011]    an outlet allowing water to pass from the channel; and 
         [0012]    a series of electrodes located within the channel; 
         [0013]    wherein the channel is a spiral. 
         [0014]    The housing is typically formed from a base and a cap. Normally the housing is made of plastic but can be made from other suitable materials. The housing may also include side covers to cover a join between the base and the cap. 
         [0015]    The inlet and outlet are typically in alignment with each other. However, the inlet and outlet may be at other angles, such as 90 degrees with each other. 
         [0016]    The electrodes are typically located in the channel closer to the outlet than the inlet. The electrodes may be formed from any suitable material, such as titanium. The electrodes may be supplied with a mono-polar or bi-polar charge. 
         [0017]    The electrodes may be removable from the channel. The electrodes may be individually replaced. The electrodes may be mounted to a central member. The central member may form part of the channel. The central member may be removable. 
         [0018]    The electrodes may form part of an electrode cartridge. The electrode cartridge may be removable from the housing. The cartridge may include the central member which is used to mount the electrodes. An inner bracket may be also be used to mount electrodes to the central member. An outer member may also be used in mounting the electrodes to the central member. 
         [0019]    The electrodes may be flat or curved. One or more edges of the electrodes may be arcuate in shape. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    Embodiments of the invention will now be described with reference to the accompanying figures in which: 
           [0021]      FIG. 1  is a front view of an electrolytic cell according to an embodiment of the invention; 
           [0022]      FIG. 2  is a rear view of the electrolytic cell as shown in  FIG. 1 ; 
           [0023]      FIG. 3  is a perspective view of an electrolytic cell as shown in  FIG. 1 ; 
           [0024]      FIG. 4  is an exploded perspective view of the electrolytic cell as shown in  FIG. 1 ; 
           [0025]      FIG. 5  is a perspective view of an electrode cartridge in accordance with the first embodiment of the invention; 
           [0026]      FIG. 6  is a partial perspective view of the cartridge shown in  FIG. 5 ; 
           [0027]      FIG. 7  is a perspective view of part of the cartridge as shown in  FIG. 5 ; and 
           [0028]      FIG. 8  is an exploded perspective view of part of the cartridge as shown in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0029]      FIGS. 1 to 4  show an electrolytic cell  10  used for chlorination of pool water. The electrolytic cell  10  includes a housing  20  and an electrode cartridge  30 . 
         [0030]    The housing  20  is made up of a base  40 , a cap  50  and two side covers  60 . The cap  50  is removably attached to the base  40  by a series of cap bolts  51  which extend around a periphery of the cap  50 . Bolt holes  41  are located within the base  40  for location of the cap bolts  51  to attach the cap  50  to the base  40 . A seal  70  is located between the cap  50  and the base  40  to ensure a join between the cap  50  and the base  40  is water tight. 
         [0031]    The side covers  60  fit over the join between the cap  50  and the base  40  to cover the cap bolts  51 . The side covers  60  have a series of male members  61  which fit into associated female receivers  42  located on the base  40  to hold the side covers  60  to the base  40 . The front side cover  60  also includes a conductor housing cover  62  to cover a conductor box  52  located on the cap  50 . 
         [0032]    An inlet  80  is located at one end of the base  40  with an outlet  90  located on the other end of the base  40 . Both the inlet  80  and the outlet  90  have associated pipe connectors  100  to enable the housing  20  to be connected to associated pipes (not shown). The inlet  80  and outlet  90  are in alignment with each other. However, it should be appreciated that this may not necessarily be the case depending on the design of a pool chlorination system. 
         [0033]    The electrode cartridge  30 , shown in more detail in  FIGS. 5 to 9 , includes a removable central member  110 , inner bracket  120 , outer bracket  130  and a series of electrodes  140 . The removable central member  110  is made of plastic and is shaped so that it fits into the housing  20 , extending both into the base  40  and into the cap  50 . The sides  111  of the removable central member  110  are shaped so that the sides  111  abut against the cap  50  and the base  40 . 
         [0034]    The outer bracket  130  and inner bracket  120  are used to mount the series of electrodes  140 . The inner bracket  120  is removably attached to the removable central member  110  using attachment members  121  located on an inner surface  122  of the inner bracket  120 . An outer surface  123  of the inner bracket  120  has a series of inner bracket recesses  125  which are used to mount the electrodes  140 . 
         [0035]    The outer bracket  130  also has a series of outer bracket recesses  131  located on the inner surface  132  of the outer bracket  130 . A top  133  and bottom  134  of the outer bracket  130  have a series of apertures  135  located through the top  133  and bottom  134  of the outer bracket  130 . This is to allow water to pass through the bracket  130  and over the electrodes  140 . The outer bracket  130  is connected to the inner bracket  120  using an interference fit. The top  133  of the outer bracket  130  is shaped so that it fits snugly against an inner surface  132  of the cap  50 . 
         [0036]    Each electrode  140  in the series is a flat plate and has an arcuate outer edge  141  and inner edge  142 . The electrodes  140  are shaped so that they will fit easily within the curved housing  20 . It should be appreciated that the electrodes  140  may be sized, shaped and made from a variety of materials which would be evident to a person skilled in the art. 
         [0037]    The electrodes  140  are electrically connected using two conductors  150  (i.e. cathodes or anodes) which pass through the cap  50  via the conductor box  52  and through associated holes in the electrodes  140 . The conductors  150  are threaded at each end so that a conductor bolt  141  can be placed on either end of a conductor  150  to hold the series of electrodes  140  tightly against the inner bracket  120  and outer bracket  130 . It should be appreciated that the connection of the electrodes  140  to the conductors  150  is well known in the art. It should also be appreciated that the current used may be varied. For example, the mono-polar or bi-polar current may be used. 
         [0038]    When the removable central member is  110  located within the housing  20 , a channel  160  in the shape of a spiral is formed. The spiral shaped channel  160  extends from the inlet  80 , through the base  40 , through the cap  50 , back into the base  40  and out the outlet  90 . It should be appreciated that the shape and size of the spiral shaped channel  160  may be varied depending on the particular requirement of the electrolytic cell  10  and associated plumbing of a pool&#39;s filtration system. 
         [0039]    In use, water flows into the channel  160  through the inlet  80 . The direction of water flow through the channel  160  is indicated by arrows  43  located on the base  40 . The water then passes through the base  40  and into the cap  50  passing around an arcuate edge  112  of the removable central member  110 . Water does not pass between the housing  20  and the sides  111  of the removable central member  110  due to the shape of the sides  111  of the removable central member  110  matching the housing  20 . 
         [0040]    Water then passes through the apertures  135  in the top  133  of the outer bracket  130 . As the top  133  of the outer bracket  130  abuts against the inner surface of the cap  50 , water must pass through the apertures  135  of the top  133  of the outer bracket  130 . This reduces the area that the water can flow through. Accordingly, the velocity of the water is increased as it passes through the apertures  135  in the top  133  of the outer bracket  130 , passes past the electrodes  140  and out through the apertures  135  in the bottom  134  of the outer bracket  130 . This increase in velocity of the water may potentially reduce the build up of calcium on the electrodes  140 . The water then passes through the base  40  and out of the outlet  90 . 
         [0041]    In use, the electrolytic cell  10  may be used in both a horizontal and vertical position. In the event of a pump failure, any excess hydrogen gas build up will be trapped within the cap  50 . Any further build up will cause the water level to ultimately drop below the electrodes  140  stopping the production of dangerous hydrogen. 
         [0042]    The spiral shape of the channel  160  allows the inlet  80  and outlet  90  to be in alignment. This increases hydraulic efficiency as the water does not need to pass through any 90 degree turns. Instead, the water moves from the inlet  80  to the outlet  90  via the spiral shaped channel  160  which has increased hydraulic efficiency compared to traditional electrolytic cells  10 , as shown in U.S. Pat. No. 4,861,451. 
         [0043]    It will also be appreciated that various other changes and modifications may be made to the embodiment described without departing from the spirit and scope of the invention.