Patent Publication Number: US-2019193000-A1

Title: Glass cartridge filters especially useful as part of water-circulation systems of swimming pools or spas

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/608,588, filed Dec. 21, 2017, and having the same title as appears above, the entire contents of which application are hereby incorporated herein by this reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to fluid-filtration equipment, systems, and methods and more particularly, but not necessarily exclusively, to modular, stackable filter units containing glass. 
     BACKGROUND OF THE INVENTION 
     Many water-circulation systems for swimming pools and spas include at least one filter. Under influence of a pump, water may be evacuated from a vessel such as a pool or spa, passed through the filter, and thereafter returned to the vessel. Because the evacuated water typically is laden with debris (e.g. dirt, leaves, sticks, bacteria), passing it through a filter allows capture of some or most of the debris, resulting in cleaner water being returned to the pool or spa. 
     A common filter for these circulation systems contains a (relatively dense) bed of sand particles. As debris-laden water passes through the sand bed, some debris is captured in the bed, thereby eliminating it from the water stream. Periodically the bed must be backwashed to remove the built-up debris. Sand also is prone to clumping and calcifying and, when clumped, may create channels between sand grains allowing water to flow unfiltered. 
     Consequently, filters containing solid mesh material also are used with pools and spas. Cartridges containing pleated mesh, for example, are common in the industry. When soiled, the cartridges may be withdrawn from their containers and washed with water to remove captured dirt and debris, following which they may be returned to their containers. 
     Pool and spa water additionally may be treated chemically to enhance its cleanliness. Conventionally chlorine is employed as the primary sanitizing chemical. Silver ion-based technologies also exist. The MagnaPool system of the Zodiac Pools group of companies (“Zodiac”) provides yet another, magnesium-based, type of chemical treatment for pool and spa water. Coagulating effects of magnesium tend to clog standard pleated cartridges, however, sometimes requiring them to be discarded rather than re-used. 
     Zodiac thus recommends using glass filtration—rather than employing (only) sand or pleated mesh filters, for example—in connection with its MagnaPool system. Beds of glass particles are less dense than similar beds of sand and thus admit more efficient cleaning. Rather than capturing dirt and debris solely mechanically, the glass does so in part electrostatically (in the applicant&#39;s understanding). Glass further resists breakdown better than sand particles when backwashed, minimizing cracks in which bacteria can lodge. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide containers for glass filtration media. The containers advantageously are modular and stackable, allowing their use as replacements in certain existing cartridge filters, for example. The containers further may be backwashed using simply a garden or similar hose, consistent with governmental regulations in certain areas. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-B  are perspective views of an exemplary container consistent with the present invention. 
         FIG. 2  is an exploded perspective view of the container of  FIGS. 1A-B . 
         FIG. 3  is a perspective, partially cross-sectioned view of stackable containers of  FIGS. 1A-B . 
         FIGS. 4A-B  are perspective views of sets of stacked containers of  FIGS. 1A-B . 
         FIG. 5  is a perspective, partially cross-sectioned view of the stack of containers of  FIG. 4A  within a cartridge filter tank. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1A-5  illustrate exemplary container  10  of the present invention. Container  10  beneficially may include basket  14  and lid  18 . Lid  18  may be secured to basket  14  (as by interlocking threads, for example) in use, hence defining a structure suitable for containing material and, if desirable, removable from basket  14  to remove or replace the contained material. Preferably confined within container  10  is media such as glass particles available for use for purposes of filtering water of swimming pools or spas. 
     As shown, both basket  14  and lid  18  have circular cross-sections. Although this configuration is advantageous for placement of container  10  within, for example, cartridge filter tank  22  (see  FIG. 5 ), it is not necessary. Indeed, each of basket  14  and lid  18  may have any suitable shape. Both basket  14  and lid  18  also are shown as having perforated walls: Outer side wall  26  and nominally lower wall  30  of basket  14  may be perforated, as may be nominally upper wall  34  of lid  18 . The perforations allow water to pass into and out of container  10 , reducing the head loss that passage of water through container  10  otherwise would create. 
     Basket  14  and lid  18  preferably are made of “rigid” plastic or other suitable material. In this sense, “rigid” means that, when combined into container  10 , these components are capable of supporting a designated weight without collapsing or otherwise deforming materially. In some versions of the invention, the designated weight may range between 5-30 kilograms, although lower or higher values may be designated as needed. 
     Accordingly, containers  10  may be stacked, one atop another, as illustrated in  FIGS. 3, 4A -B, and  5 .  FIG. 5  details three such stacked containers  10  fitted within tank  22 , allowing the containers  10  to substitute for the pleated mesh or other filters previously present in tank  22 . Of course, tank  22  or another tank could be made so as to be dedicated to receive one or more containers  10 . 
     To facilitate stacking and unstacking of containers  10 , lid  18  may be outfitted with handle  38 . In the version of container  10  shown in  FIG. 1A , for example, upper wall  34  may have reduced size along a portion of its periphery so as to form semi-circular recess  42 . Handle  38  additionally may be semi-circular, allowing it to fit within recess  42  flush with wall  34  when not in use. By contrast, for use, handle  38  may be removed from recess  42  to a position similar to that illustrated in  FIG. 1A , allowing it to be grasped easily by a person. 
     Whereas outer side wall  26  beneficially forms a cylinder, each of lower wall  30  and upper wall  34  is generally annular in shape. Extending nominally upward from internal periphery  46  of lower wall  30  of basket  14  may be internal collar  50 , which itself may be perforated. Likewise, extending nominally upward from internal periphery  54  of upper wall  34  may be alignment collar  58 . Unlike internal collar  50 , alignment collar  58  preferably is unperforated. 
     When lid  18  is secured to basket  14  for use, collars  50  and  58  are aligned (nominally vertically) so as to form an unfettered central passage in which water may flow. Moreover, when two containers  10  are stacked, alignment collar  58  of the “lower” container  10  may be received within internal collar  50  of the “upper” container  10 , establishing the modular, nestable nature of the devices. The solid nature of collar  58  (effectively making it a flange) also may help prevent collapse of the container  10  when handle  38  is grasped and pulled. 
     Arrows in  FIG. 1A-B  identify some ways in which water may flow into, out of, and through container  10 . Water entering container  10  (other than merely passing through the unfettered central passage) contacts the glass particles or other filtration media contained therein, thereby cleansing the water of at least some particulates before the water exits container  10  for eventual return to the pool or spa. 
     The present invention hence defines a manner in which glass media may be used for filtration. Modular containers such as baskets may be partially or completely filled with particles of glass or other filtration material, and one or more containers may then be inserted into a cartridge filter. This allows for the glass filtration to occur within the small footprint of the cartridge filter. It also facilitates cleaning of the containers, which may be easily lifted out of cartridge filters and washed with standard hoses. 
     Preferably, perforations of a container are less than one millimeter (1 mm) in size, so that particles of at least this size may be successfully contained with the container. A particular perforation size is not critical to the invention, however, as filtration particles of smaller or larger size may be selected instead. Containers advantageously may be strong enough to support the maximum number of fully-loaded containers intended to be stacked upon the bottom-most container. The containers also beneficially are uniformly sized and shaped to facilitate efficient stacking. 
     The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of the present invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of the invention. Filter elements such as those disclosed in International Patent Application Publication No. WO 2016/185159 (the “&#39;159 PCT Application”) may be utilized in connection with the present invention if desired, and the entire contents of the &#39;159 PCT Application are incorporated herein by this reference.