Abstract:
A method and apparatus for heating an outdoor swimming pool. The apparatus includes a substantially buoyant web having a first end, a second end, a first exterior surface and a second exterior surface. A water distributor is attached to the first end of the web for flowing pool water longitudinally adjacent the first exterior surface of the web. A conduit in flow communication with the distributor provides a flow of water from a swimming pool pump to the water distributor. The water distributor is disposed to distribute the flow of water adjacent the first exterior surface of the web. The invention provides a pool heating device that is effective to heat pool water without using water flow conduits along the length of the web and is simply constructed for low cost, portability and case of manufacturing.

Description:
FIELD OF THE INVENTION 
     The invention relates to a pool heating device and more particularly to an floating apparatus adaptable for heating pools which is lightweight and easily storable. 
     BACKGROUND 
     Swimming pools are heated for two reasons, (1) to extend the swimming season to earlier in the spring and later in the fall and (2) to provide more comfortable water temperatures throughout the swimming season. Pool heating is typically conducted with several types of heating systems. One type of heating system circulates pool water through an electric or gas-fired water heating system. A second type of heating system uses solar panels through which the pool water is circulated. A third type of heating system uses floating panels through which water is circulated, the panels being heated by the sun. Another type of pool cover for heating pools consists of a floating structure containing channels for flow of water therethrough. The floating structure is heated by the sun which in turn heats the water flowing through the channels. 
     Despite the variety of pool heating devices available, there continues to be a need for a simple economical pool heating device which is easily adaptable to various size pools and which does not rely on a channeled web for maintaining water contact with the heating surface of the web. There is also a need for a pool heating device that does not consume precious natural resources or that adds pollutants to the environment. Such a device should be relatively inexpensive to own and operate yet be effective to sufficiently heat swimming pool water. 
     SUMMARY OF THE INVENTION 
     With regard to the above and other needs and advantages, the invention provides an outdoor swimming pool heating apparatus. The apparatus includes a substantially buoyant web having a first end, a second end, a first exterior surface and a second exterior surface, the second exterior surface being positionable to face away from a water surface of the swimming pool and the first exterior surface being positionable adjacent and facing the water surface. A water distributor is attached to the first end of the web adjacent the first exterior surface of the web for flowing pool water longitudinally adjacent the first exterior surface of the web. A conduit in flow communication with the distributor provides a flow of water from a swimming pool pump to the water distributor. The water distributor is disposed to distribute the flow of water adjacent the first exterior surface of the web. 
     In another aspect the invention provides a method for heating a swimming pool. The method includes providing a swimming pool heating apparatus including, a substantially flexible elongate web having a first end and a second end and a first surface and a second surface, a water distribution device attached to a first end of the flexible elongate web adjacent the first surface of the web for flowing pool water longitudinally adjacent the first surface of the web, and a flexible tubular conduit connected to the water distribution device for providing water from a swimming pool pump to the water distribution conduit. The web is configured to float on pool water and the web does not contain water flow conduits therein for flow of water from the water distribution device along the first or second surface of the web. The web is floated on a surface of the swimming pool water. The flexible tubular conduit is connected to a swimming pool jet for flow of water from the swimming pool pump to the water distribution device for water flow along the first surface of the web. Water is flowed along the first surface of the web while exposing the web to sunlight thereby heating the water adjacent the first surface of the web. 
     As set forth in more detail below, the invention provides a relatively light-weight, easily manufactured pool heating device which does not rely on flow of water through channels adjacent the pool water surface. Accordingly, the device according to the invention lends itself to simpler more cost effective manufacturing techniques as compared to the formation of channelled web. The apparatus of the invention is also more reliable with regard to operation since there are no water flow channels to fail and cause loss of water circulation adjacent the web. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS: 
     Further advantages of the invention are apparent by reference to the detailed description when considered in conjunction with the figures, which are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein: 
     FIG. 1 is a plan top view, not to scale, of a pool water heating apparatus according to the invention; 
     FIG. 2 is side elevational view, not to scale, of a pool water heating apparatus according to the invention; 
     FIG. 3 is a side view, not to scale, of a water distribution device for a pool water heating apparatus according to a first embodiment of the invention; 
     FIG. 4 is a schematic representation of a swimming pool system and pool water heating apparatus according to the invention; 
     FIG. 5 is side elevational view, not to scale, of a pool water heating apparatus according to an alternative embodiment of the invention; 
     FIG. 6 is a plan view, not to scale of multiple connected pool water heating apparatus according to the invention; 
     FIG. 7 is a perspective view of a swimming pool and pool water heating apparatus according to the invention; 
     FIG. 8 is a side elevational view, not to scale, of a fan-jet nozzle for a pool water heating apparatus according to a second embodiment of the invention; 
     FIG. 9 is a plan view, not to scale, of a fan-jet nozzle for a pool water heating apparatus according to a second embodiment of the invention; 
     FIG. 10 is a bottom plan view of a flexible web and attached fan-jet nozzle for a pool water heating device according to a second embodiment of the invention; 
     FIG. 11 is a schematic representation of a conventional swimming pool system; and 
     FIG. 12 is a schematic representation of a swimming pool system and pool water heating apparatus according to another embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With initial reference to FIGS. 1-5, details of the apparatus and method of the invention will now be described. A preferred embodiment of a pool heating apparatus  10  includes three main components: an elongate flexible web  12 , a water distribution device  14  and a flexible conduit  16 . The web  12  is in flow communication with the water distribution device  14 . The conduit  16  is also in flow communication with the water distribution device  14  for feeding water from swimming pool circulation jets to the water distribution device  14 . The circulation jets are conventional to swimming pool pump circulation systems. 
     The web  12  is preferably made from a light weight, substantially flexible material which has acceptable resistance to ultraviolet (UV) light and pool chemicals such as chlorine, hypochlorite, ozone and the like. It is preferred that the web  12  have a specific gravity of less than about 1 and have an overall dark color such as black, brown, dark blue, dark green and the like. A particularly preferred color for the web  12  is black. The web material may be made of vinyl, expanded foam or other relatively durable light weight materials. If the web  12  has a specific gravity of more than about 1, air pockets may be provided in the web by laminating two web materials together to provide enclosed air filled spaces or pockets, or, in the alternative, floatation devices  18  may be periodically attached to the web  12  as shown in FIGS. 1 and 5. 
     In order to inhibit accumulation of water on the surface of the web  12  opposite the water surface of the pool, slits or holes  20  are preferably provided in the web  12 . Multiple webs  12  may be attached together with, for example, hook and loop fasteners, zippers, tape and the like, to provide a wider or longer web  12  for heating pool water. It is preferred that the web  12  have a total surface area which is about 10 to about 25 percent of the total pool water surface area. A particularly preferred web  12  has a length L ranging from about 5 to about 10 feet and a width W ranging from about 40 to about 60 inches. 
     As shown in FIG. 2, the web  12  has a first end  22  attached to the water distribution device  14  and a second distal end  24 . The second distal end  24  preferably contains a floatation enhancing device  26  such as foam which enables the second end  24  of the web  12  to remain on the surface of the water. A first surface  28  of the web  12  is attached on the first end  22  thereof to the water distribution device  14  by any known method for attaching a web  12  to a channel or header. Such methods include tape, adhesive, rivets, screws, crimped flanges and the like. The method for attaching the web  12  to the distribution device  14  is not particularly important to the invention. 
     The water distribution device  14  is shown in detail in FIGS. 2 and 3. The device  14  is a substantially rectangular conduit  30  containing a plurality of spaced-apart apertures  32  or other openings, holes or slits for flow of water therethrough. The apertures  32  are preferably located or disposed to induce water flow along the first surface  28  of the web  12 . Water is supplied to the water distribution device  14  from the swimming pool inlet water jets  34  (FIG. 4) or other source of recirculating water. The conduit  30 , shown in FIGS. 1-3 is preferably made of a light weight, durable material such as plastic, aluminum and the like which is also substantially resistant to UV light and pool chemicals. The conduit  30  is preferably about 50 to about 60 inches long, about 1 to about 2 inches high and about 3 to about 5 inches wide. In order to prevent the water distribution device  14  from sinking, foam blocks may be attached to the ends of the conduit  30  or inserted in the conduit  30  to provide sufficient buoyancy. 
     The flexible conduit  16  connected to the water distribution device  14  may be any suitable hose or tubing which can be attached to the distribution device  14  by means of a fitting  36  or any other means known to those skilled in the art. The flexible conduit  16  is thus connected on a first end  38  to the fitting  36  and on a second end  40  to an inlet water jet  34  (FIG.  4 ). As shown in FIG. 4, water is circulated through a filter  42  for a pool  44  by flow through one or more pool drains  46  and skimmers  48  (FIG. 7) to an underground conduit  50  which is connected to the suction of a pump  52 . The pump  52  pumps the water through the pool filter  42  and through an inlet conduit  54  to the inlet water jets  34 . The water is then directed by flexible conduit  16  through the water distribution device  14  for flow longitudinally along the first surface  28  of the web  12 . The water flowing along the first surface  28  of the web  12  is heated by sunlight  56  which heats the web  12  by exposure of a second surface  58  of the web thereto. 
     As set forth above, the pool heating apparatus  10  may include a single web  12  and water distribution device  14  or may include multiple webs  12  and water distribution devices  14  as shown in FIGS. 5 and 6. When the apparatus includes multiple webs  12 , water is preferably supplied to two or more of the water distribution devices  14  for the webs  12  by a common flexible conduit  60  (FIGS. 6 and 7) which is connected to both water distribution devices  14 . The flexible conduit  16  provides flow of water from the inlet jets  34  to the common conduit  60 . 
     An alternative design of a water distribution device which may be attached to web  12  is shown in FIGS. 8-10. Instead of an elongate rectangular conduit  30 , as described above, the water distribution device may be a fan-jet nozzle device  62  as shown. The fan-jet nozzle  62  includes a fitting connection  64  on a first end  66  thereof for connection to the flexible conduit  16 . Water flows into the nozzle  62  through a throat region  68  into a substantially triangular-shaped nozzle region  70 . The nozzle region  70  terminates at a distal end  72  which contains a slit  74  or multiple slits or holes for flow of water therethrough. 
     In FIG. 10, the fan-jet nozzle  62  is attached to the first surface  28  of the flexible elongate web  12 . When a fan-jet nozzle  62  is used to provide water flow adjacent the first surface  28  of the web  12 , it is preferred to include ribs  76  or channels which are formed on the first surface  28  of the web in a radiating or starburst pattern. The ribs  76  preferably channel the water discharged from the fan-jet nozzle  62  across the width W of the first surface  28  of the web  12 . For a web  12  having a length L of about 15 feet and a width W of about 8 feet, the fan-jet nozzle  62  is attached to about the center of the web  12  toward the first end  22  thereof. The ribs  76  radiate from the aperture  74  of the fan-jet nozzle  62  for a distance of about 3 feet along the first surface of the web  28 . The ribs  76  preferably extend below the first surface  28  of the web  12  about 0.5 to about 1.5 inches and are preferably spaced apart no closer than about two inches. In the alternative, the web  12  may be a molded web have radiating or starburst channels molded therein to provide channeling of water adjacent the first surface  28  of the web in the same manner the ribs  76  provide channeling. 
     The advantages of the invention will now be illustrated with reference to heating a residential swimming pool. A typical residential swimming pool  44  is about 20 feet wide and about 40 feet long and holds about 30,000 gallons of water. The circulation rate of water in the pool  44  typically ranges from about 25 to about 50 gallons per minute. Two, three or more inlet water jets  34  provided on a pool of this size and the pool contains 1 to 2 skimmers  48  and at least one bottom drain  46 . The inlet water jets  34  are typically positioned opposite the skimmers  48  to provide a surface flow pattern that transports any floating debris such as leaves quickly to the skimmers for capture and removal. The bottom drain  46  induces vertical movement of pool water and prevents thermal stratification of pool water. Without the apparatus of the invention, the water flow from the inlet water jets  34  loses its velocity rapidly because of the formation of eddy currents and back mixing (FIG.  11 ). Hence, the velocity of water from the jets  34  is dissipated in a relatively short distance D. 
     In contrast to the free jet situation described above, the apparatus  10  of the invention induces water flow at a high velocity for substantially the entire length L of the web  12 . While not desiring to be bound by theory, the movement of water adjacent the first surface  28  of the web  12  is believed to be due to a physical phenomenon known as the “Coanda Effect”. The Coanda effect refers to the fact that a fluid (liquid or gas) introduced parallel to and near a relatively smooth surface will preferentially flow near to and along that surface. Hence, the fluid will maintain its velocity over a greater distance than if the fluid were flowing as a free jet. Because the recirculated pool water flows closely adjacent the first surface  28  of the web for substantially the entire length L of the web, the recirculated pool water provides a high temperature differential between the first surface  28  of the web and the upper surface of the pool water thereby providing high heat transfer between the sunlight heated web and the pool water. 
     Another embodiment of the invention is illustrated in FIG.  12 . In this embodiment, a stream of water is directed by a pool inlet jet  80  to the first surface  28  of the web  12  without using a flexible conduit or hose directly connected to a water distribution device  14  as shown in FIG. 4 or to a fan jet nozzle as shown in FIG.  10 . One end of the web  12  is preferably attached to a flotation device  82 , selected from foam materials and flotation aids such as closed hollow cylinders or pipes attached to the web which in turn is secured to one end of the pool by a weight  84  and connecting rope  86 . In all other respects, this embodiment of the invention provides the advantages described above by causing water flow from the inlet pool jets  80  to flow along first surface  28  of the web  12  thereby heating the water by intimate contact with the solar heated web. 
     To demonstrate the heating potential of the apparatus  10  of the invention, assume a swimming pool 20 feet wide and 40 feet long contains 30,000 gallons of water. An apparatus  10  of the invention having a web length L of 12 feet and a web width W of 10 feet provides 120 square feet of heating area. Assuming the apparatus  10  has a sunlight collection efficiency of 85% and the available solar heating capacity is 3000 BTU/ft 2  per day, the heat transferred to the pool water is given by the following equation: 
     
       
         3000 BTU/ft 2  per day×0.85×120 ft 2 =306,000 BTU/day. 
       
     
     Since the heat capacity of water is about 1 BTU/lb-° F., the temperature rise of the pool water is found by the following: 
     
       
         Temperature rise (ΔT)=1 lb-° F./BTU×306,000 BTU/day/250,200 lbs=1.22° F./day. 
       
     
     Hence, the invention provides effective pool water heating with a relatively light weight, easily manufactured apparatus  10 . 
     The foregoing embodiments of this invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide illustrations of the principles of the invention and its practical application, and to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as is suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.