Abstract:
A pool cleaning apparatus for cleaning the bottom and sidewalls of a swimming pool has an exterior housing through which water is circulated and at least one source of water-sterilizing ultraviolet (UV) radiation in the form of a straight, circular and/or curvilinear tube that is positioned on the interior of the housing so that the amount of any bacteria in the water circulated past the UV radiation source is reduced.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to robotic pool cleaners having self-contained water sterilization capabilities.  
       BACKGROUND OF THE INVENTION  
       [0002]     It is known that ultraviolet, or UV, light sources have the capability of killing bacteria. Ultraviolet light sources can be in the form of straight and circular tubes and can be powered by 12 to 24-volt power systems.  
         [0003]     It is also known that UV light can be harmful to the human eye and that such exposure should be extremely limited.  
         [0004]     There are various methods for treating water in swimming pools to reduce the bacteria count to ensure the health and safety of those using the pool. The most common disinfectant is chlorine which can be added as a dry chemical through the swimming pool&#39;s water circulation system. Alternatively, chlorine ions can be added using an electrochemical apparatus in which the chlorine is generated by the disassociation of sodium chloride that is added to the pool in relatively small quantities.  
         [0005]     Treatment of the pool&#39;s water using ozone generated by an electrochemical process is also known.  
         [0006]     The use of on-board devices that are secured to a robotic pool cleaner to generate chlorine and ozone as the pool cleaner traverses the bottom and/or sidewalls of a pool during its cleaning cycle have been disclosed. Since a substantial volume of water is drawn through the particulate filter system inside of the pool cleaner housing and passed through its outlet port, it would be advantageous to provide additional means for further disinfecting the filtered water as it passes through the housing.  
         [0007]     It is therefore a principal object of the present invention to provide a novel means for disinfecting the water while it is on the interior of the pool cleaner housing.  
         [0008]     It is another object of the invention to provide an apparatus and method for treating swimming pool water using a source of ultraviolet radiation that is safe and that does not present a risk of exposure to users of the swimming pool.  
         [0009]     It is a further object of the invention to provide a source of ultraviolet radiation that is effective and yet protected from damage by inadvertent contact with users of the pool and/or recreational equipment and toys that are being used in and around the pool.  
       SUMMARY OF THE INVENTION  
       [0010]     The above objects and other advantages are obtained by incorporating one or more sources of ultraviolet radiation that are on the inside of a pool cleaner housing and positioned so that the UV radiation is directed toward water that is passing through the pool cleaner housing during the cleaning cycle. The sources of UV radiation can include one or more straight or curvilinear tubes, e.g., circular tubes that are secured in appropriate waterproof housings to the interior surface of the pool cleaner housing. The tubes can also be secured to a waterproof housing for a drive motor, a pump or a chlorine generator unit, electrically connected to a power source inside of the housing or cover. In the case of battery-powered units, the UV radiation source can be electrically connected to the battery housing.  
         [0011]     In a preferred embodiment, the tubes are provided with an appropriate reflector or barrier to minimize the exposure of the interior of the housing to the UV radiation source at close range.  
         [0012]     In an especially preferred embodiment, the water passing through the housing is channeled to move in close proximity to the radiation source to enhance the bactericidal effectiveness of the exposure.  
         [0013]     The UV light source is preferably installed in a transparent waterproof protective housing that includes any necessary circuitry and circuit elements to provide the required power characteristics to activate the radiation source. The tube is preferably provided with a standard socket member for receiving a power plug. Power can be provided by an on-board rechargeable battery or from a power supply unit located outside of the pool and delivered via the pool cleaner&#39;s power cord.  
         [0014]     The appropriate protective shielding to prevent deterioration of the interior surface of the pool cleaner housing can be provided in any number of ways known to the art. For example, the interior of the housing can be sprayed with an appropriate UV resistant coating subsequent to its manufacture and before installation of other components. The UV tube itself can be provided with an appropriate reflector by chemical deposition and/or mechanical shielding applied to the exterior of the tube. Mechanical shielding in the form of an adhesively bonded layer or film of UV barrier material can be applied to the interior of the housing.  
         [0015]     A further alternative is to fabricate the pool cleaner housing from a plastic composition that has been especially formulated to provide enhanced UV radiation resistance. As a general rule, the plastics conventionally used to manufacture these housings do have a reasonably high resistance to UV radiation from exposure to the sun.  
         [0016]     Various forms and shapes of mechanical baffles and/or barriers can be installed to form channels However, as will be recognized by one of ordinary skill in the art, such mechanical barriers should not present obstacles to the flow of water as to create turbulence and frictional losses that will detract from the overall cleaning efficiency of the unit.  
         [0017]     The pool cleaner equipped in accordance with the invention is preferably provided with a water sensing switch so that power to the UV radiation source is turned off when the unit is removed from the water and/or when the pump is turned off and water is not moving through the housing. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     The invention will be further described with reference to the attached drawings in which the same or similar elements are identified by the same numbers, and in which:  
         [0019]      FIG. 1  is a sectional side elevation view of a pool cleaner housing with certain of its components removed for simplicity and shown partly in phantom illustrating one embodiment of the invention;  
         [0020]      FIG. 2  is a view similar to  FIG. 1  showing a second embodiment of the invention;  
         [0021]      FIG. 3  is a schematic illustration of an electrical circuit illustrating several alternatives suitable for use with the embodiments of  FIGS. 1 and 2 .  
         [0022]      FIG. 4  is a perspective view of a typical waterproof motor housing fitted with UV radiation sources in one configuration;  
         [0023]      FIG. 5  is a view similar to  FIG. 4  illustrating another configuration of UV radiation sources secured to the housing;  
         [0024]      FIG. 6  is a schematic illustration, partly in section, showing yet another embodiment of the invention;  
         [0025]      FIG. 6A  is an enlarged view of a portion of the apparatus constructed in accordance with the invention;  
         [0026]      FIG. 7  is another schematic illustration, partly in section, illustrating another embodiment employing a circular UV tube secured to the pump motor housing;  
         [0027]      FIG. 7A  is an enlarged view of a portion of the apparatus constructed in accordance with the invention; and  
         [0028]      FIG. 8  is a schematic illustration, partly in section, showing an installation of the embodiment of  FIG. 5   
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]     Referring to  FIG. 1 , the pool cleaner housing  10  is of a typical configuration known in the art and is fitted with a base plate  12  having water inlet openings  14  through which water is drawn for passage through a filter bag  16  and discharged through outlet opening  18  in the upper portion of the housing. A pump  20  has an impeller  21  for moving the water drawn through the base plate  12  for eventual discharge from the housing. The pump motor receives power from a power cord  22  that is connected either to batteries or an external power source (not shown) both of which are conventional and well known in the art.  
         [0030]     In this embodiment, several vertical UV radiation sources in the form of straight tubes  30  are mounted on the interior surface of the pool cleaner housing appropriate fittings  32 . The tubes can be secured by any of a wide variety of known fasteners that will permit their removal for replacement. Also shown in  FIG. 1  are a series of aligned baffles  40  that channel the water in close proximity to the surface of the tubes and also provide an opaque barrier and reflective surface to minimize the exposure of other components inside the housing to the UV radiation. The channeling of the water serves to increase the time of exposure for a given volume of moving water by reducing turbulent and random flow patterns.  
         [0031]     In  FIG. 1  and the embodiments described below, the means of circulating the water is illustrated as an on-board pump. As will be understood by those of ordinary skill in the art, the water can be circulated by an external pump and delivered by a pressurized flexible tube to the pool cleaner. The same principles and advantages of the invention will apply to such a system.  
         [0032]     Referring now to  FIG. 2 , an alternative embodiment is illustrated in which two circular tubes  36  are secured to the internal surface of the pool cleaner. Again, a system of baffles can be provided to channel a portion of the water in close proximity to the tubes to enhance the bactericidal effect. The baffles also serve the purpose of minimizing exposure of the other internal components to UV radiation. It will be understood that a single tube  36  can be installed, or more than two tubes, depending upon the size of the unit, radiation emission level of the tubes, water flow characteristics and other factors that are within the skill of the art to determine.  
         [0033]     With reference to the schematic circuit diagram of  FIG. 3 , it will be seen that the power cord from the external power supply can alternatively include an additional conductor  23  for supplying power to the one or more UV tubes.  
         [0034]     Referring now to the further embodiment illustrated in  FIG. 4 , two straight UV radiation tubes  30  are mounted directly on a surface of a waterproof drive motor housing  29 . The ends of the tube can be fitted with electrical connectors and are inserted into appropriate socket recesses  27  formed in the housing  29 . Electrical power is provided to the sockets from the interior leads of the housing. As will be apparent to those of ordinary skill in the art, all connections and conductor passages are waterproof.  
         [0035]     As also shown in  FIG. 4 , a protective baffle  40  is mounted on the surface adjacent tube  30  in order to reduce the exposure of the adjacent molded plastic components projecting from the surface of the housing to UV radiation. It will be understood that baffles can be integrally formed during the original molding of the plastic parts comprising the housing.  
         [0036]     In a further related embodiment illustrated in  FIG. 5 , the elongated straight UV source tubes  30  are mounted on either side of the surface of the housing  29  and in close proximity. Electrical leads  31  extend from the end of the respective tubes through a sealed orifice  32  into the interior of the housing where they receive power.  
         [0037]     As also shown in  FIG. 5 , a transparent baffle  40  is shown mounted in position to channel water from the sides of the housing  29  across the elongated surface of tubes  30 .  
         [0038]     Referring now to  FIGS. 6 and 6 A, a further embodiment is illustrated in which a pair of UV radiation-emitting tubes  30  are mounted on the housing for an on-board chlorine generator  60 . As in the earlier embodiments, the electrical conductors  31  are admitted to the interior of the chlorine generator housing where they are connected to a power source. A baffle  40  is provided on the right side, as shown in  FIG. 6 , to both channel the water rising through the pool cleaner housing in close proximity to the surface of tube  30  and to also provide a radiation barrier to reduce the exposure of other components to the potentially damaging radiation.  
         [0039]     As will be understood from the previous disclosure, additional vertical tubes  30  can be similarly mounted on the drive motor housing  28  and on the pump motor housing  22  or other assembly fittings. The flow of water in the conventional pool cleaner illustrated is upwards through the baseplate and exiting through an outlet port in housing  10  located above the pump impeller  21 . Thus, laminar flow past the one or more UV radiation-emitting tubes in this arrangement can be readily achieved by the use of baffles to maintain a given volume of water in relatively close proximity to the radiation source for a predetermined period of time. These flow rate determinations for exposure purposes are within the skill in the art.  
         [0040]     With reference to  FIGS. 7 and 7 A, there is illustrated another representative embodiment in which a circular tube  36  is mounted on the pump motor assembly. Additional circular tubes can be mounted at other positions on the pump motor assembly or, as illustrated in  FIG. 2 , on the interior surface of the pool cleaner housing.  
         [0041]     As illustrated in  FIG. 7A , one or more cylindrical baffles  40  can be positioned to provide a generally laminar flow in the vicinity of the tube  36 . Depending upon the configuration of the outlet port and relative location of the tube  36  on the pump housing, a barrier to eliminate exposure to viewers in the vicinity of the pool cleaner through the outlet opening  18  can be installed as a safety measure.  
         [0042]     As shown in the exploded view of  FIG. 7A , the tube  36  is provided with conductor leads  31  that extend through a seal  36  in the waterproof pump housing where they are connected to the pump&#39;s power source. In the illustration of  FIG. 7 , the power is alternatively supplied via conductors attached to a waterproof junction box  45 , which in turn receives power from the external power supply  50  via floating power cable  52 .  
         [0043]     Referring to  FIG. 8 , a further illustration of the installation of the embodiment of  FIG. 5  is shown. Power is provided by external source  50 , via power cord  52 . The UV radiation tube  30  receives its power from the pump motor  20 . In this embodiment, when power to the pump is discontinued, the UV radiation also ceases  
         [0044]     As will be apparent to those of ordinary skill in the art, the invention is equally adaptable to pool cleaners in which the source of pressurized water is provided by a remote pump and is delivered to the unit by a flexible hose that is secured to an inlet port in the housing.  
         [0045]     The above descriptions and the specific embodiments are intended as illustrative of the method and apparatus of the invention. As will be apparent to those of ordinary skill in the art, various other modifications and arrangements can be undertaken without departing from the spirit of the invention, the scope of which is to be determined with reference to the claims that follow.