Patent Publication Number: US-7220353-B2

Title: Skimmer with rotatable filter cartridge for spas and pools

Description:
This application is a continuation-in-part of Ser. No. 10/992,578, filed Nov. 18, 2004, the complete disclosure of which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates broadly to water filtration. More particularly, this invention relates to a skimmer having a replaceable cartridge filter. 
     2. State of the Art 
     Conventional skimmers for pools and spas include a weir which is hinged at the bottom and provided with a float at the top. Behind the weir is a sump in which a filter or a basket is placed. A filter pump is coupled to the sump and draws water from the pool or spa over the weir and into the sump through the filter or basket. The floating weir assures that the pool/spa water is drawn from the surface into the sump. This causes floating waste to be drawn across the surface of the water and into the skimmer. 
     In skimmers which have baskets rather than filter cartridges, the owner can see waste accumulate in the basket and will know to empty the basket periodically. Skimmers which utilize replaceable filter cartridges are different. A good example of such a skimmer is shown in U.S. Pat. No. 4,637,873 issued Jan. 20, 1987 to DeSousa et al. A cylindrical filter cartridge is disposed vertically in the skimmer housing below the weir. It is difficult or impossible to determine visually whether the filter needs to be replaced. In addition, because of the way the filter cartridge is disposed in the skimmer housing, it is possible that the outer surface will become unevenly, coated with waste, thereby requiring replacement more frequently than if the filter were evenly coated. 
     The previously incorporated parent application discloses a skimmer which includes a housing, a skimmer face plate coupled to the housing, and a flexible weir gate coupled to the face plate. When the filter pump is activated, the weir gate flexes to allow water to flow both over the top of the face plate and in a vertical column between the face plate and the housing. The interior of the housing has a curved wall so that when a column of water passes the weir gate and is pulled down into the housing, a whirlpool effect is realized. A vertical filter cartridge is mounted on a rotational bearing in the housing so that it can spin about its axis. The inlet of a filter pump is coupled to the cartridge via the bearing. The inlet of the pump is also coupled to a below the surface water inlet via a check valve. When the filter is clean, water is drawn through it by the pump and the filter spins about its axis due to the whirlpool effect of the column of water. When the filter reaches a threshold dirt covering, water is no longer drawn through it and the draw through the housing is decreased, causing the check valve to open to allow more water to the pump. As the flow rate through the housing decreases, the rate of rotation of the cartridge decreases, thus giving a visual indication that it needs to be replaced. Spinning the cartridge during operation also causes it to be more evenly coated with dirt. This makes more efficient use of the cartridge. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a skimmer and filter for a pool or spa. 
     It is another object of the invention to provide a skimmer which uses replaceable filter cartridges. 
     It is a further object of the invention to provide a skimmer which provides a visual indication of when a filter cartridge needs to be replaced. 
     It is also an object of the invention to provide a skimmer which makes more efficient use of filter cartridges. 
     In accord with these objects, which will be discussed in detail below, the skimmer according to the invention includes a housing, a skimmer face plate coupled to the housing, and a flexible weir gate coupled to the face plate. When the filter pump is activated, the weir gate flexes to allow water to flow both over the top of the face plate and in a vertical column between the face plate and the housing. The interior of the housing has a curved wall so that when a column of water passes the weir gate and is pulled down into the housing, a whirlpool effect is realized. A vertical filter cartridge is mounted on a rotational bearing in the housing so that it can spin about its axis. The inlet of a filter pump is coupled to the cartridge via the bearing. The inlet of the pump is also coupled to a below the surface water inlet via a check valve. When the filter is clean, water is drawn through it by the pump and the filter spins about its axis due to the whirlpool effect of the column of water. When the filter reaches a threshold dirt covering, water is no longer drawn through it and the draw through the housing is decreased, causing the check valve to open to allow more water to the pump. As the flow rate through the housing decreases, the rate of rotation of the cartridge decreases, thus giving a visual indication that it needs to be replaced. Spinning the cartridge during operation also causes it to be more evenly coated with dirt. This makes more efficient use of the cartridge. 
     According to an illustrated embodiment, the weir gate flexes about a central mount and two filter cartridges are arranged side by side. When clean, the filter cartridges spin in opposite directions. 
     According to the present invention, at least one water jet is arranged between the weir gate and the cartridge. The jet is arranged to spray water at the cartridge to assist in the spinning of the cartridge. According to a preferred embodiment, the jet is coupled to water under pressure via a valve which closes when the cartridge is dirty. 
     Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a portion of a skimmer assembly according to the invention; 
         FIG. 2  is a schematic top view of a skimmer assembly according to the invention with the pump off; 
         FIG. 3  is a schematic top view of a skimmer assembly according to the invention with the pump on; and 
         FIG. 4  is a schematic side elevation view of the skimmer assembly with the pump on. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to  FIGS. 1-4 , a skimmer  10  according to the invention includes a first housing  12  and a skimmer face plate  14  opening into the housing. The face plate  14  is dimensioned to form lateral vertical gaps  16 ,  18  which allow water W to flow in vertical columns between the face plate  14  and the first housing  12 , and a top gap  19  over which water W can flow. This is illustrated best in  FIGS. 3 and 4 . In addition, and as shown in  FIGS. 1-4 , the face plate  14  has a flexible weir gate  15  coupled to it by fasteners  17  which are centrally located to allow the edges of the gate  15  to flex. When water passes through the gaps  16 ,  18 ,  19  between the weir gate  14  and the first housing  12 , the sides and top of the weir gate  15  flex. Flexion at the top allows water to be skimmed across the surface. Flexion at the sides allows water to enter the housing  12  in columns. When the pump is deactivated, the weir gate  15  reassumes its original shape and covers the gaps  16 ,  18 ,  19 . 
     As seen best in  FIGS. 2 and 3 , the interior of the first housing  12  has a pair of curved walls  20 ,  22  each adjacent one of the gaps  16 ,  18 . The curved walls are arranged so that when a column of water passes through the gaps  16 ,  18  between the face plate  14  and the first housing  12 , and over the weir gate  15 , a whirlpool effect is realized. This is illustrated by the circular arrows in  FIG. 3 . A pair of vertical filter cartridges  24 ,  26  are mounted beneath the face plate in a second housing  27  (shaped similar to the first housing  12 ) as shown in  FIGS. 2-4 . Each cartridge is mounted on a rotational bearing, one of which  28  is shown in relation to cartridge  24  in  FIG. 4 . The rotational bearings allow the filter cartridges to spin under the influence of the whirlpools as shown by the arrows in  FIG. 3 . Optionally, the filter cartridges may be provided with radially extending longitudinal fins  36  to aid in spinning the cartridge under the influence of the whirlpool. Although the drawing shows only two fins, three or four are preferred. Other rotational aids may also be provided to the filter cartridges, such as paddle wheel elements at one or both ends of the cartridges. 
     According to the present invention, at least one water jet and preferably two  42 ,  44  are arranged between the weir gate  15  and the cartridges  24 ,  26 . The jets are arranged to spray water at the cartridges to assist in the spinning of the cartridge. 
     The inlet of a filter pump  30  is coupled to the cartridge  24  via the bearing  28  as shown in  FIG. 4 . The inlet of the pump is also coupled to a water inlet  32  via a check valve  34 . The water inlet  32  is located below the surface of the water W. It will be appreciated that the outlet of the pump  30  returns filtered water back to the pool/spa. When the filter cartridges  24 ,  26  are clean, water is drawn through them by the pump  30  and the cartridges spin about their axes due to the whirlpool effect of the column of water. When a cartridge reaches a threshold dirt covering, water is no longer drawn through it and the check valve  34  opens to allow more water the pump  30 . The check valve  34  may be coupled to a shut off valve  46  which shuts off water to the jets  42 ,  44  when the check valve  34  opens. When water is no longer being drawn through the filter cartridges and water is no longer being sprayed by the jets  42 ,  44 , the cartridges stop spinning, thus giving a visual indication that the cartridges need to be replaced. Spinning the cartridges during operation also causes them to be more evenly coated with dirt. This makes more efficient use of the cartridge. 
     Alternative to providing the valve  46 , the weir gate  15  and the jets  42 ,  44  may be arranged so that neither supplies enough water pressure to spin the cartridges, i.e. that that cartridges only spin when they are clean and the jets are spraying. 
     In yet another alternative embodiment, the jets  42 ,  44  are operated with sufficient pressure to rotate the cartridges regardless of the amount of dirt loaded onto the cartridges. 
     There have been described and illustrated herein several embodiments of a pool/spa skimmer. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while the illustrated skimmer has two filter cartridges, it will be appreciated that a skimmer with a single cartridge and at least one jet could be constructed incorporating the features of the invention. In a single filter embodiment, the face plate would be configured to allow only a single column of water to enter the housing. Instead of a flexible weir gate, a spring biased hinged gate could be used. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as claimed.