Abstract:
A fluid filter system with cartridge filters housed in a tank in which each cartridge filter has a lift tube positioned concentrically within each cartridge filter. The lift tubes extend from a support plate, which divides the tank into a raw fluid chamber and a processed fluid chamber, toward a tank cover. The lift tubes have inlet ports proximate to the tank cover so that the fluid surface in the tank is maintained at or near an upper end of the cartridge filters. This configuration enables the lift tubes to exhaust excess air in the tank through the lift tubes and out of the filter system through outlet ports in the processed fluid chamber. By exhausting air from the filter system, the capacity of the system is not compromised by the air and the expected life of the cartridge filters is not reduced.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention is directed generally to fluid filters, and more particularly to fluid filters having replaceable filters.  
       BACKGROUND  
       [0002]     There exists numerous conventional fluid filters for removing contaminants, such as shown in U.S. Pat. Nos. 3,720,322 and 4,187,179. One particular style of fluid filter, such as those used in drinking water and pool cleaning systems, includes a generally cylindrical tank housing a removable cartridge filter, as shown in U.S. Pat. Nos. 4,561,979 and 5,316,677. A conventional cartridge filter is often formed from a filter media positioned between bottom and top plates. Fluids are filtered by passing the fluids into the tank, passing the fluids through the filter media, and expelling the filtered fluids through an outlet tube in the cartridge filter.  
         [0003]     One conventional filter system, as shown in  FIG. 1 , includes a plurality of filter cartridges positioned longitudinally within a tank and concentrically about supports extending from a bottom plate toward the tank cover. The filter system is configured such that raw fluids enter the system and pass through the filter cartridge, whereby contaminants are removed from the fluid. The processed fluids collect in hollow central cores within the cartridge filters and flow from the hollow cores through an outlet port in the tank. As shown in  FIG. 1 , the supports have cross-sections that resemble angle iron, such that at least a portion of each support is open along its length. The supports have openings that extend from end to end. The elongated openings in the supports enable processed fluids to flow into the support at any level in the raw fluid chamber. During operation, air builds up in the tank and is not exhausted through the elongated opening in the support because air is prevented from entering the outlet ports by the fluids contained in the central core of the cartridge filters. As a result, air accumulates in the tank and upper portions of the cartridge filters that are exposed to the air are unused. The accumulation of air in the tank reduces the capacity of the filter system and reduces the useful life of the cartridge filters. Thus, a need exists for an inexpensive filter system capable of using a variety of filter cartridges and capable of automatically bleeding air from the filter system.  
       SUMMARY OF THE INVENTION  
       [0004]     This invention is directed to a filter system for removing contaminants or other materials from a fluid, such as water. The filter system is formed from a tank divided into a raw fluid chamber and a processed fluid chamber and having one or more cartridge filters. Each cartridge filter is positioned concentrically around a lifting tube extending from a support plate into the raw fluid chamber. The lift tubes may include inlet ports positioned in the lifting tube in close proximity to an upper end of the cartridge. This configuration of lifting tubes enables the fluid level in the tank to be maintained at the height of the upper end of the cartridge filters, thereby enabling substantially all of the surface area of the cartridge filters to be used during operation of the filter system. Excess air entering the system may be expelled from the system through the lift tube.  
         [0005]     filter system includes a tank separated by a support plate into a raw fluid chamber and a processed fluid chamber. The raw fluid chamber of the tank may be configured to receive at least one cartridge filter. The tank may include an inlet port in the raw fluid chamber for receiving raw fluids and an outlet port in the processed fluid chamber for expelling processed fluids. The filter system also includes one or more lift tubes releasably attached to the support plate and extending toward a tank cover that seals the raw fluid chamber. The lift tube may include an inlet port proximate to the cover of the tank. Cartridge filters are positioned in the raw fluid chamber generally concentrically with the lift tubes such that the lift tubes are positioned in a hollow core of the cartridge filters. Each lift tube may have one or a plurality of cartridge filters positioned generally concentrically with the lift tube such that fluids flowing through the inlet port in the tank pass though the cartridge filter, flow toward the cover, pass through the inlet port in the lift tube proximate to the cover, and are collected in the processed fluid chamber.  
         [0006]     The lift tube of the filter system regulates the fluid level in the raw fluid chamber and may be releasably coupled to the support plate. The lift tube may include a protrusion extending from an outer surface of the lift tube. The protrusion may serve numerous purposes. In at least one embodiment, the protrusion may be a collar and assist in sealing the lift tube to the support plate. The protrusion may also extend a sufficient distance from the lift tube such that the protrusion may contact the cartridge filter so that the cartridge filter may be removed from the tank by withdrawing the lift tube. The protrusion may also position the lift tube within an aperture in the support plate at a proper height.  
         [0007]     In at least one embodiment, the cartridge filters may be sealed within the raw fluid chamber with a cartridge sealing plate. The cartridge sealing plate may be releasably coupled to a rod such that the cartridge filters may be sealed between the cartridge sealing plate, which may be proximate to the tank cover, and the support plate. The cartridge sealing plate may include one or more plugs corresponding to the cartridge filters. The plugs may include a collar for sealing a cartridge filter to a cartridge sealing plate and a dome configured to extend into the hollow core of the cartridge filter for positioning the cartridge sealing plate relative to the cartridge filter.  
         [0008]     During operation, fluids flow into the filter system through the inlet port in the tank and collect in the raw fluid chamber. The fluids fill the raw fluid chamber and pass through the filter cartridge and into the inner hollow core of each cartridge filter in the tank. The membrane forming the filter cartridge removes materials from the fluid and allows at least a portion of the fluid to pass through the membrane. The type of materials removed from the fluid by the membrane may vary depending on the type of membrane used. After the fluids have reached the height of the inlet port of the lift tube, the fluids and excess air flow into the lift tube and collect in the processed fluid chamber. The processed fluids may be expelled from the tank through the outlet port.  
         [0009]     An advantage of this invention is that the lift tubes enable the tank to automatically expel excess air from the system, thereby enabling fluids to contact substantially all, if not all, of the cartridge filters. By preventing the buildup of air in the system, the capacity of the filter system is not reduced, and the useful life of the cartridge filters contained in the tank are not reduced.  
         [0010]     Another advantage of this invention is that the lift tubes are removable and capable of being used to pull cartridge filters from the tank, thereby resulting in large time savings in comparison to conventional filter systems in which lift tubes are manually withdrawn without the assistance of the lift tubes.  
         [0011]     Yet another advantage of this invention is that the lift tubes enable the cartridge filters to removed individually and easily replaced in contrast to conventional cluster designed chambers in which all of the cartridge filters in a tank are removed at once then necessitating a time consuming process of disassembly, cartridge filter replacement, and reassembly.  
         [0012]     Another advantage of the invention is that the cartridge filter positioning plate may be used to seal the cartridge filters at various heights in the tank, thereby enabling cartridge filters with varying heights and sizes to be used without having to resize the tank.  
         [0013]     These and other embodiments and advantages are described below. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, disclose the principles of the invention.  
         [0015]      FIG. 1  is an exploded perspective view of a conventional fluid filter system.  
         [0016]      FIG. 2  is an exploded perspective view depicting aspects of the fluid filter system of this invention.  
         [0017]      FIG. 3  is a cross-sectional, assembled view of the fluid filter system shown in  FIG. 2 .  
         [0018]      FIG. 4  is a perspective view of a cartridge sealing plate of this invention.  
         [0019]      FIG. 5  is a detail view of the connection between the cartridge sealing plate and a cartridge, as shown in  FIG. 3  at detail line  5 - 5 .  
         [0020]      FIG. 6  is a detail view of the lift tube inserted into the adapter in the support plate, as shown in  FIG. 3  at detail line  6 - 6 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     As shown in  FIGS. 2-6 , this invention is directed to a filter system  10  having one or a plurality of cartridge filters  12  positioned within a tank  14  for removing a variety of materials from a fluid that is passed through the filter system  10 . The tank  14  includes a lift tube  16  positioned within each cartridge filter  12  that extends from a bottom surface  18  of a raw fluid chamber  20  of the tank  14 . The height of the lift tube  16  establishes the height of the fluid contained within the tank  14  during operation. Air that builds up within the tank  14  in a volume exceeding the space between a tank cover  22  and an upper surface of fluid  24  at the height of the lift tube  16  is exhausted from the tank  14  through the lift tube  16 . By establishing a lift tube  16  height proximate to an upper end  26  of the cartridge filter  12 , air is prevented from accumulating in the tank below the height of the lift tube  16 . As a result, substantially all of the surface area of the cartridge filter  12  is used during operation as fluids are passed through the filter  12 .  
         [0022]     The filter system  10  may include a tank  14  for containing cartridge filters  12 . The tank  14  may be substantially cylindrical or be formed from other appropriate shapes. The capacity of the tank  14  may vary depending on the anticipated flow rate and application. The tank  14  may be formed from non-corrosive materials such as, but not limited to, stainless steel, or other appropriate materials to increase the life of the tank. The tank  14  may be sealed using tank cover  22 , o-ring  19 , and retention ring  21 . The tank  14  may be divided into a raw fluid chamber  20  and a processed fluid chamber  28 . In at least one embodiment the raw fluid chamber  20  is positioned above the processed fluid chamber  28 , and the chambers  20  and  28  are separated by a support plate  30 . The tank  14  may include an inlet port  23  positioned proximate to the support plate  30  for supplying raw fluids to the filter system  10 . The tank  14  may also include an outlet port  25  in the processed fluid chamber  28  for expelling processed fluids from the filter system  10 .  
         [0023]     As shown in  FIG. 3 , the support plate  30  may be positioned proximate to a bottom end  32  of the tank  14  and positioned within the tank  14  so that the raw fluid chamber  20  may contain the cartridge filters  12 . The support plate  30  may be coupled to an inner surface  34  of the tank  14  using welds or other mechanical attachment devices. The support plate  30  includes a plurality of apertures  36  for directing processed fluids from inner aspects of cartridge filters  12  to the processed fluid chamber  28 . The apertures  36  may be any appropriate size, and in at least one embodiment, may be sized slightly smaller than an inner hollow core diameter  38  of the cartridge filter  12 . The apertures  36  are also sized to accommodate a lift tube  16 , and in at least one embodiment, an adapter  40 . The adapter  40  is sized to fit within the aperture  36  and to provide a seal between the lift tube  16  and the support plate  30 , as shown in  FIG. 6 . In at least one embodiment, the adapter  40  may be bell shaped and permanently attached to the support plate  30 ; however, the adapter  40  may have other appropriate shapes and be attached to the support plate  30  using other mechanisms. The lift tube  16  may be releasably positioned within the adapter  40  by inserting the lift tube  16  into the adapter  40 .  
         [0024]     The lift tube  16  may also include a one or more protrusions  42  extending from an outer surface  44  of the lift tube  16 . The protrusions  42  may be configured to engage the cartridge filter  12  when the lift tube  16  is removed from the tank  14  so that the lift tube  16  may be used to remove the cartridge filter  12  from the tank  14 . The protrusion  42  may also be used to form a seal between the lift tube  16  and the adapter  40  or the support plate  30 . In at least one embodiment, as shown in  FIG. 2 , the protrusion  42  is formed from a collar  46  extending around an outer surface  44  of the lift tube  16  proximate to a lower end  48 .  
         [0025]     The lift tube  16  may extend, when installed in the tank  14 , from the support plate  30  toward the tank cover  22 . The height of the lift tube  16  establishes the height of the fluid contained within the raw fluid chamber  20  outside of the cartridge filters  12 . In at least one embodiment, the lift tube  16  may extend from the support plate  30  and terminate in close proximity to the tank cover  22 . In particular, the lift tube  16  may terminate in close proximity to a cartridge sealing plate  50 , as shown in  FIG. 5 . In these embodiments, fluids passing through the filter cartridge  12  must first reach the height of the inlet port  52  in the lift tube  16  before passing into the processed fluid chamber  28 . Thus, the volume of air may be maintained at a level such that substantially all, if not all, of the cartridge filter  12  is used during operation, rather than just a lower portion, as is the case when a large volume of air is present in the tank  14 .  
         [0026]     In the embodiment depicted in  FIG. 2 , four lift tubes  16  extend from the support plate  30  and terminate proximate to the cartridge sealing plate  50 . Each lift tube  16  may accommodate one or more cartridge filters  12 . As shown in  FIGS. 2 and 3 , each lift tube  16  may have two cartridge filters  12  positioned concentrically around the lift tube  16 . Thus, in this embodiment, eight cartridge filters  12  may be contained in the tank  14 . The cartridge filters  12  may be sealed against the support plate  30  using the cartridge sealing plate  50 , as shown in  FIG. 5 . The cartridge sealing plate  50  may be releasably compressed against the cartridge filters  12  by tightening a mechanical connector  54 , such as, but not limited to, a nut or other appropriate device on a rod  57 . In at least one embodiment, the rod  57  may extend the length of the tank  14  generally along a longitudinal axis  56  of the tank  14 . When the cartridge sealing plate  50  is compressed against the cartridge filters  12 , fluids are not capable of entering the inlet port  52  of the lift tube  16  without first passing through the filter cartridge  12 .  
         [0027]     The cartridge filters  12  may include filter media for removing any number of materials, chemicals, contaminants, and the like from the fluids passed through the filter system  10 . The cartridge filters  12  may be, but are not limited to being, activated carbon filters, sedimentary filters, submicron filters, and other appropriate filters depending on the fluid desired to be removed from a fluid by the filter system  12 . The configuration of the tank  14  and the ability of the cartridge sealing plate  50  to be releasably secured within the tank  14  at varying heights enables the filter system  10  to accommodate cartridge filters  12  having various heights. Thus, the filter system  10  may use many different sized conventional filter cartridges  12  or custom sized filter cartridges without having to adjust the size of the tank  14 .  
         [0028]     The cartridge sealing plate  50  used to seal the cartridge filters  12  may include one or more plugs  62  for sealing the upper ends  26  of the cartridge filters  12 . In at least one embodiment, as shown in  FIG. 4 , the cartridge sealing plate  50  may include four plugs  62  positioned generally equidistant from a center point on the plate  50  and each other. In other embodiments, the cartridge sealing plate  50  may include other numbers of plugs  62  and have plugs in alternative positions on the plate  50 . The plug  62  may include a collar  64  with a diameter larger than the inner hollow core diameter  38  of the cartridge filter  12 . The collar  64  may be configured from a lip of the metal forming the plug  62 . The collar  64  is configured to form a seal against the upper end  26  of the cartridge filter  12 . The plug  62  may also include a dome  66  protruding from the plug  62  and sized to fit in the inner hollow core of the cartridge filter  12 .  
         [0029]     In an alternative embodiment, the inlet port  52  of the lift tube  16  need not be positioned on an upper end  58  of the lift tube  16 . Rather, the inlet port  52  may be positioned in an outer wall  60  forming the lift tube  16 . The inlet port  52  may be positioned in the lift tube  16  proximate to the upper end  26  of the cartridge filter  12 . In this configuration, substantially all of the cartridge filter  12  is in contact with fluids contained in the raw fluid chamber  20 .  
         [0030]     During operation, fluids flow into the filter system  10  through the inlet port  23  and into the raw fluid chamber  20 . The fluids fill the raw fluid chamber and pass through the filter cartridge  16  and into the inner hollow core  68 . The membrane forming the filter cartridge  16  removes materials from the fluid and allows at least a portion of the fluid to pass through the membrane. The type of materials removed from the fluid by the membrane may vary depending on the type of membrane used. After the fluids have reached the height of the inlet port  52  of the lift tube  16 , the fluids flow into the lift tube  16  and collect in the processed fluid chamber  20 . The processed fluids may be expelled from the tank  14  through the outlet port  25 .  
         [0031]     The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this 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 this invention.