A skimmer assembly has an upper housing and a lower housing. The lower housing contains a removable filter cartridge and the upper housing contains a floating cylindrical weir and a floating rotatable member atop the floating weir. The walls of the upper housing are curved and the water entrance includes a vertical slot which allows water to enter in a column, hit the curved wall and cause a whirlpool which causes the rotatable member to spin. The preferred embodiment includes a disposable annular filter disc removably attached to the rotatable member.

CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is related to co-owned co-pending application Ser. No. 10/992,449, filed Nov. 18, 2004, entitled “Skimmer with Flexible Weir Gate for Spas and Pools”, the contents of which are hereby incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates broadly to water filtration. More particularly, this invention relates to a skimmer having a replaceable cartridge filter and a rotating member which indicates when the cartridge needs to be replaced. 
         [0004]    2. State of the Art 
         [0005]    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. 
         [0006]    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. 
         [0007]    The previously incorporated related application discloses a skimmer housing having a face plate which is dimensioned to allow water to enter the housing in a vertical column. The interior of the housing has a curved wall so that when a column of water passes the face plate into the housing, a whirlpool effect is realized. A vertical filter cartridge is mounted on a rotational bearing and the whirlpool effect causes it to spin when water is being drawn into the skimmer by a pump. When the filter cartridge reaches a threshold dirt covering, water is no longer drawn through it and it stops spinning. Thus, if the owner looks inside the skimmer at the filter cartridge and sees that it is not spinning, that is an indication that it needs to be replaced. However, this requires an inspection below water level. 
         [0008]    Another issue with spa/pool skimmer filter cartridges is oil which is present on the surface of the water. When oil enters the skimmer it tends to clog the filter cartridge and require more frequent replacement than would be the case in the absence of oil. 
       SUMMARY OF THE INVENTION 
       [0009]    It is therefore an object of the invention to provide a skimmer and filter for a pool or spa. 
         [0010]    It is another object of the invention to provide a skimmer which uses replaceable filter cartridges. 
         [0011]    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. 
         [0012]    It is also an object of the invention to provide a skimmer which makes more efficient use of filter cartridges. 
         [0013]    It is an additional object of the invention to control the amount of oil that gets to a filter cartridge. 
         [0014]    It is still another object of the invention to provide a visual indication of when a filter cartridge needs to be replaced which is easy to see from the outside of the skimmer housing. 
         [0015]    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. 
         [0016]    A vertical filter cartridge is mounted in the bottom of the housing. A floating cylindrical weir assembly is mounted above the cartridge and a rotatable member (spinner) is placed above the cylindrical floating weir assembly. The inlet of a filter pump is coupled to the cartridge and 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. 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. 
         [0017]    The spinner has a central cylindrical hub (which is centered by the floating cylindrical weir assembly) and a plurality of radially extending arms. Each of the arms terminates with upper and lower fins. When the whirlpool is created in the skimmer housing, the fins are engaged by the moving water and cause the spinner to spin. When the check valve opens, the whirlpool stops and the spinner stops spinning. According to an aspect of the invention, a replaceable annular filter disc is provided between the central hub and lower fins of the spinner. The filter disc catches oil from the surface of the water before it can reach the filter cartridge. 
         [0018]    According to an illustrated embodiment, the weir gate flexes about a central mount and two filter cartridges are arranged side by side with a pair of floating cylindrical weirs and a pair of spinners. When the filter cartridges are clean, the spinners spin in opposite directions. Since the spinners are on the surface of the water, approximately 8-10 inches above filter cartridges, they are easy to see. 
         [0019]    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 
         [0020]      FIG. 1  is a schematic top view of a skimmer assembly according to the invention with the pump on; 
           [0021]      FIG. 2  is a schematic side elevation view in partial section of the skimmer assembly with the pump off; 
           [0022]      FIG. 3  is a top plan view of a spinner according to the invention; 
           [0023]      FIG. 4  is a section taken along line A-A in  FIG. 3 ; 
           [0024]      FIG. 5  is a perspective view of the spinner; 
           [0025]      FIG. 6  is a perspective view of a filter disc according to the invention; and 
           [0026]      FIG. 7  is a perspective view of a filter disc installed on the spinner. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Turning now to  FIGS. 1 and 2 , a skimmer  10  for a spa tub or pool 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. According to the preferred embodiment, 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  to prevent dirt within the housing  12  from escaping back into the spa tub/pool. 
         [0028]    As seen best in  FIG. 1 , 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 arrows in  FIG. 1 . As illustrated in  FIG. 1 , a pair of spinners  24 ,  26  are located in the first housing  12 , each being associated with a respective curved wall  20 ,  22 . 
         [0029]    Referring now to  FIG. 2 , a second housing  28  is mounted below the first housing  12 . The housing  28  includes a replaceable filter cartridge  30 . Though only one cartridge  30  is seen in  FIG. 2 , a separate filter cartridge is provided for each spinner ( 24 ,  26  in  FIG. 1 ), and a separate housing  28  is provided for each cartridge. The filter cartridge  30  is coupled to a pump  32  which draws water W through the filter  30  and to a pump outlet which may be above or below the surface of the water W. When the cartridge  30  reaches a threshold dirt covering, water is no longer drawn through it and a check valve  34  opens to supply water to the pump from a water inlet below the surface of the water W. 
         [0030]    A telescoping cylindrical weir assembly  38  is mounted above the filter housing  28  in the first housing  12 . A first stationary part  38   a  is located substantially concentric with the filter cartridge  30  and has an upper inward flange  38   c . A second floating part  38   b  having a lower outward flange  38   d  is captured within the stationary part  38   a  but is free to move up and down, limited only by the engagement of the flanges  38   c ,  38   d . The floating part  38   b  has an annular air space  38   e  which gives it buoyancy. 
         [0031]    Turning now to  FIGS. 3 through 5 , the spinner  24  (which is identical to the spinner  26 ) has a central cylindrical hub  24   a , and a plurality of radially extending arms  24   b  through  24   i , each of which terminates with a pair of fins (one upper and one lower)  24   j  through  24   q . As seen best in  FIG. 4 , the hub and the arms (including the fins) are hollow. This provides an air space which gives the spinner buoyancy. The presently preferred dimensions of the spinner are an overall diameter of eight inches as shown in  FIG. 3  with a hub diameter of two inches as shown in  FIG. 4 . The fin pairs are two and one eighth inches top to bottom and one half inch inside to outside. 
         [0032]    Referring back to  FIG. 2 , it can be seen that the inner hub  24   a  of the spinner  24  is captured inside the upper end of the floating part  38   b  of the cylindrical weir assembly  38  to physically reference the spinner  24  relative to the cylindrical weir assembly  38  and filter cartridge  30  below. As explained above, when the pump  32  is drawing water through the filter cartridge  30 , a whirlpool is formed by the walls of the first housing  12 . This causes the spinner  24  to rotate on the surface of the water. The status of the spinner can be seen by looking into the housing  12  through the opening  19 . Alternatively, a window can be provided in the top of the housing  12 . 
         [0033]    Referring now to  FIGS. 6 and 7 , another aspect of the invention is to provide disposable filter discs  40  for use with the spinners  24 . The discs have a central hole  40   a  which is dimensioned to allow (snug) passage of the central hub  24   a  of the spinner. The overall diameter of the discs  40  is such that an annular filter space is created which extends from the hub  24   a  to the inside walls of the lower fins of the spinner. The disc  40  is preferably made of filter paper and also preferably provided with ribs (e.g.  40   b - 40   i ) which impart some rigidity to keep it in place when the spinner filter assembly is first placed in the skimmer and when the assembly is removed. The filter  40  prevents (or reduces) oil on the surface of the water from entering the filter cartridge. 
         [0034]    There have been described and illustrated herein a skimmer assembly and a rotatable member for indicating when a filter cartridge needs to be replaced. 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 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 also be appreciated that the skimmer could be assembled without a weir gate and still work, though not necessarily as well. Also while the spinner has been shown to have eight arms, a different number could be used. Furthermore, while specific dimensions have been disclosed, these dimensions are not critical. 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.