Patent Publication Number: US-2013228499-A1

Title: Vertical Filter

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority from U.S. Provisional Patent Application No. 61/590,594, filed on Jan. 25, 2012, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a vertical filter. More specifically, the present invention relates to a vertical filter for use in a spa tub or similar device that includes an upper cartridge-type filter removably secured to a lower canister that holds a replaceable depth filter. 
     2. Description of Related Art 
     Conventional cartridge-type filter assemblies, for both spa and pool circulation systems, typically feature a layer of pleated fabric filter material arranged in a hollow cylindrical shape around a hollow core of plastic material that features a plurality of perforations or is formed as an open grid, which provides structural support to the fabric filter material. Water passing through the circulation system flows radially into the core through the fabric filter layer, where debris is filtered from the water supply. 
     Such conventional filters provide only a single filtration of the water as it cycles through the circulation system. Accordingly, it can take a long time for the single filter to adequately clean the water. Further, conventional filters are not effective at filtering several different types of contaminants in the circulated water, such as oils. Thus, these contaminants will remain in the circulated water despite filtering. 
     SUMMARY OF THE INVENTION 
     Accordingly, there is a general need for a vertical filter for a spa or pool circulation system that includes a depth load filter capable of filtering debris contaminants from circulated water in a fewer number of passes through the filter so as to reduce filtering time and is capable of filtering different water contaminants. 
     According to one embodiment, the present invention provides a vertical filter assembly for a spa or pool circulation system that includes a depth load filter combined with a pleated fabric depth filter. As the water is circulated through the vertical filter assembly, debris is first filtered from the circulated water by the pleated fabric depth filter and is then directed to a depth load filter connected to the pleated filter. The depth load filter is configured to remove additional debris and contaminants from the circulated water in order to quickly and efficiently clean the circulated water. The pleated fabric depth filter and the depth load filter are connected in such a manner that the pool or spa owner is able to easily remove the filter assembly, disassemble the filters, replace one or both filters, and then re-install the filters in the circulation system. 
     According to another embodiment, the vertical filter assembly includes a top filter assembly, the top filter assembly including a primary filter layer of pleated polyester fabric defining a top end and a bottom end, a top end member attached to the top end of the filter layer, a bottom end member defining a bottom opening attached to the bottom end of the filter layer, and a hollow core surrounded by the filter layer and in fluid communication with the filter layer via a plurality of apertures; and a canister, the canister including a canister body defining a hollow interior of the canister, a top lip defining an open top of the canister, and a bottom wall. The hollow interior of the canister is in fluid communication with the hollow core of the top filter assembly via the bottom opening in the bottom end member and the open top of the canister and is configured to contain a secondary filter. The top filter assembly is removably secured to the canister. 
     According to yet another embodiment, a vertical filter assembly includes a primary filter; a canister in fluid communication with the primary filter, the canister including a canister body defining a hollow interior of the canister and a bottom wall; and a depth filter positioned within the hollow interior of the canister and supported above the bottom wall of the canister, the depth filter acting as a secondary filter. The depth filter is removable from the hollow interior of the canister. 
     According to still another embodiment, a depth filter includes a filter body made of meltblown polypropylene, the filter body having a substantially hourglass shape defined by an upper conical half and a lower conical half joined at a narrow center portion and defining a wide top end portion and a wide bottom end portion, respectively, the filter body having an internal sidewall defining a central passageway extending through the filter body from a top end to a bottom end of the filter body; a top member attached to the top end of the filter body that closes off the central passageway at the top end of the filter body; and a bottom member attached to the bottom end of the filter body defining a flange for supporting the depth filter and a bottom opening that places the central passageway of the filter body in fluid communication with an exterior of the depth filter. The filtration characteristics of the filter body vary along a longitudinal length of the filter body. 
     According to a particular embodiment of the present invention, a vertical filter assembly is provided. The vertical filter assembly includes a top filter assembly, the top filter assembly including a primary filter; a canister in fluid communication with the top filter assembly, the canister including a canister body having a sidewall and a bottom wall that define a hollow interior of the canister; and a secondary filter positioned within the hollow interior of the canister and supported above the bottom wall of the canister. 
     According to another particular embodiment of the present invention, a water circulation system for a spa tub is provided. The circulation system includes a vertical filter assembly that includes a top filter assembly, the top filter assembly including a primary filter; a canister in fluid communication with the top filter assembly, the canister including a canister body having a sidewall and a bottom wall that define a hollow interior of the canister; and a secondary filter positioned within the hollow interior of the canister and supported above the bottom wall of the canister. The circulation system further includes a circulation pump for circulating water; at least one conduit for placing the vertical filter assembly in fluid communication with the circulation pump; at least one outlet for directing water to the spa tub; and at least one conduit for placing the circulation pump in fluid communication with the at least one outlet. 
     According to yet another particular embodiment of the present invention, a depth filter is provided. The depth filter includes a filter body made of meltblown polypropylene. The filter body has a substantially hourglass shape. Filtration characteristics of the filter body vary along a longitudinal length of the filter body. 
     Further details and advantages of the invention will become clear upon reading the following detailed description in conjunction with the accompanying drawing figures, wherein like parts are designated with like reference numerals throughout. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a perspective view of a vertical filter assembly according to an embodiment of the present invention; 
         FIG. 2  depicts a side view of the vertical filter assembly; 
         FIG. 3  depicts an exploded side view of the vertical filter assembly; 
         FIG. 4  depicts a perspective view of a top filter assembly of the vertical filter assembly; 
         FIG. 5  depicts a side view of the top filter assembly; 
         FIG. 6  depicts a cross-sectional side view of the top filter assembly; 
         FIG. 7  depicts a top view of the top filter assembly; 
         FIG. 8  depicts a bottom view of the top filter assembly; 
         FIG. 9  depicts a perspective view of a canister of the vertical filter assembly; 
         FIG. 10  depicts a side view of the canister; 
         FIG. 11  depicts a cross-sectional side view of the canister taken along line A-A in  FIG. 10 ; 
         FIG. 12  depicts a top view of the canister; 
         FIG. 13  depicts a bottom view of the canister; 
         FIG. 14  depicts a perspective view of a lock pin of the vertical filter assembly; 
         FIG. 15  depicts a perspective view of a depth filter of the vertical filter assembly; 
         FIG. 16  depicts a side view of the depth filter; 
         FIG. 17  depicts a top view of the depth filter; 
         FIG. 18  depicts a bottom view of the depth filter; 
         FIG. 19  depicts a schematic of a water circulation system for a spa tub incorporating the vertical filter assembly according to an embodiment of the present invention; 
         FIG. 20  depicts a pressure v. flow chart illustrating the pressure drop across individual components of the vertical filter assembly and combinations thereof; 
         FIG. 21  depicts a pressure v. flow chart illustrating the pressure drop across individual components of the vertical filter assembly and combinations thereof; 
         FIG. 22  depicts a turbidity chart comparing a prior art filter and a depth filter according to an embodiment of the present invention; 
         FIG. 23  depicts a pressure v. flow chart illustrating pressure drop across individual components of the vertical filter assembly; and 
         FIG. 24  depicts a side view of a cylindrical depth filter according to another embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     For purposes of the description hereinafter, spatial orientation terms, if used, shall relate to the referenced embodiment as it is oriented in the accompanying drawing figures or otherwise described in the following detailed description. However, it is to be understood that the embodiments described hereinafter may assume many alternative variations and embodiments. It is also to be understood that the specific devices illustrated in the accompanying drawing figures and described herein are simply exemplary and should not be considered as limiting. 
     With reference to  FIGS. 1-3 , a vertical filter assembly  10  is shown in accordance with an embodiment of the present invention. The vertical filter assembly  10  includes a top filter assembly  15 , a canister  30 , a lock pin  11  for securing the top filter assembly  15  to the canister  30 , and a depth filter  45  that is housed inside the interior of the canister  30 . 
     With reference to  FIGS. 4-8 , the top filter assembly  15  includes a primary filter, which includes a filter layer  16  made of a pleated polyester fabric arranged in a hollow cylindrical shape. The fabric of the filter layer  16  may be formed as such, or may be formed from a sheet of fabric material, which is pleated and subsequently joined at the edges to form a longitudinal joint, according to techniques known to those of ordinary skill in the art. A plurality of bands may be provided about the outer circumference of the filter layer for retaining the filter layer in a cylindrical shape. 
     The filter layer  16  may be made from any fabric known to be suitable to those having ordinary skill in the art. For instance, the outer filter layer may be 3 oz. REEMAY® fabric, manufactured by Fiberweb plc. 
     As stated above, the filter layer  16  is arranged in a hollow cylindrical shape defining a top end and a bottom end. A top end member  17  is disposed on the top end of the filter layer  16  and retains the filter layer  16  in its cylindrical shape. To that end, the top end member  17  may include an annular groove (not shown) in a surface thereof that is capable of receiving the first end of the filter layer  16 . The top end member  17  also includes a removable cap  18  that is removably secured to the top end member  17  in an interlocking engagement between a portion of the cap  18  and a recess formed in the top end member  17 . The cap  18  may be used to cover an opening through the top end member  17 . A dispenser  19  for bromine or other water treating chemical may be secured to the cap  18  such that the dispenser  19  is removed from the top filter assembly  15  with the cap  18 . 
     As shown in  FIG. 6 , the top filter assembly  15  includes a hollow cylindrical core  20  for supporting the filter layer  16 , which includes a sidewall with a plurality of perforations  21 . The perforations  21  place the hollow interior of the core  20  in fluid communication with the exterior surface of the sidewall. The dispenser  19  extends from the underside of the cap  18  through the opening in the top end member  17  and into the interior of the hollow cylindrical core  20 . 
     A bottom end member  22  is disposed on the bottom end of the filter layer  16  and retains the filter layer  16  in its cylindrical shape. To that end, the bottom end member  22  may also include an annular groove (not shown) in a surface thereof that is capable of receiving the bottom end of the filter layer  16 . The bottom end member  22  has an annular shape defining a bottom opening  26  with an upper portion and a connection portion  24  depending from the upper portion. A first protrusion  23  radially extends from the bottom end member  22  and includes a hole sized to receive the lock pin  11  therein. At least two tabs  25  extend radially outward from the connection portion  24 . The tabs  25  are provided for removably securing the top filter assembly  15  to the canister  30 , as will be described in further detail below. 
     Depending upon the model of spa and circumstances of use, the top filter assembly  15  may be of any suitable size. In particular, the top filter assembly  15  may have a longitudinal length of 6.5″, 8.5″, or 12″ (165 mm, 216 mm, or 305 mm) extending from the surface of the top member  17  to the bottom surface of the bottom end member  22  above the connection portion  24 . 
     With reference to  FIGS. 9-13 , the canister  30  includes a canister body  31  formed from a sidewall and a bottom wall  36  that define a hollow interior  32 . The hollow interior  32  is in fluid communication with the hollow core  20  of the top filter assembly  15  via the bottom opening  26  of the bottom end member  22  and an open top end of the canister  30 . The open top end of the canister  30  is defined by a top lip  33  having a diameter that is slightly larger than the diameter of the sidewall of the canister body  31 . The top lip  33  is configured to receive and engage the connection portion  24  of the bottom end member  22  of the top filter assembly  10  therein. A second protrusion  34  radially extends from the top lip  33  and includes a hole sized to receive the lock pin  11  therein. At least two interior grooves  35  are defined in an inside surface of the top lip  33 . The grooves  35  are L-shaped and are configured to receive and releasably engage the tabs  25  on the connection portion  24  of the bottom end member  22  of the top filter assembly  15 . The connection portion  24  of the bottom end member  22  of the top filter assembly  15  is received within the top lip  33  of the canister  30  such that the top filter assembly  15  is removably secured to the canister  30  by the releasable engagement between the tabs  25  and the L-shaped grooves  35 . This configuration allows for a user to remove the filter assembly from a circulation system, disassemble the top filter assembly  15  from the canister  30 , and replace the top filter assembly  15  and/or the depth filter  45 . 
     As shown in  FIGS. 11 and 12 , the bottom wall  36  of the canister  30  has an annular bowl shape defining an opening at the bottom end of the canister  30 . An internal flange  38  is formed in the canister  30  at the junction between the sidewall of the canister body  31  and the bottom wall  36 . The internal flange  38  supports the depth filter  45  within the hollow interior  32  of the canister  30 . A threaded coupling  37  extends outwardly from the bottom wall  36  and is in fluid communication with the opening in the bottom wall  36  so that water can pass from the hollow interior  32  of the canister  30  to a water circulation system  200  of the spa. It is to be appreciated that the canister  30  is configured to attach to different sizes of filters in the top filter assembly  15  so long as the filters have a compatible diameter and attachment mechanism. In particular, the canister  30  is compatible with a top filter assembly  15  having a longitudinal length of 6.5″, 8.5″, or 12″ (165 mm, 216 mm, or 305 mm), as discussed above. 
     With reference to  FIG. 14 , the filter assembly  10  also includes a lock pin  11  for securing the top filter assembly  15  to the canister  30 . The lock pin  11  includes a pin body  12  and a key ring  13  for handling the lock pin  11 . As shown in  FIGS. 1-3  and  8 - 12 , the first protrusion  23  and the second protrusion  34  are arranged with respect to the tabs  25  and the L-shaped grooves  35  such that the holes of the first protrusion  23  and the second protrusion  34  are aligned when the tabs  25  are fully engaged with the L-shaped grooves  35 . As discussed above, the holes of the first protrusion  23  and the second protrusion  34  are configured to receive the lock pin  11 . When aligned, the holes receive the lock pin  11  to secure the engagement between the tabs  25  and the L-shaped grooves  35 , and prevent removal of the top filter assembly  15  from the canister  30 . The configuration of the tabs  25  on the top filter assembly  15  cooperating with the grooves  35  in the canister  30  with relative rotation of the top filter assembly  15  and the canister  30  being prevented by the lock pin  11  allows for a user to remove the filter assembly from a circulation system, disassemble the top filter assembly  15  from the canister  30 , and replace the top filter assembly  15  and/or the depth filter  45 . It is to be appreciated that the top filter assembly  15  may be secured to the canister  30  by any method known to be suitable to those having ordinary skill in the art that allows for quick and simple disassembly of the vertical filter assembly  10 , replacement of the filters  15 ,  45 , and reassembly. 
     With reference to  FIGS. 15-18 , the depth filter  45  acts as a secondary filter for the vertical filter assembly  10  and has a substantially hourglass shape and a filter body  46  made from meltblown polypropylene throughout and having an internal sidewall, which defines a central passageway  49  extending through the filter body  46  from a top end to a bottom end of the filter body  46 . The depth filter  45  also includes a top member  47  that closes the top end of the central passageway  49  of the filter body  46  and a bottom member  48  having an annular shape, which defines a bottom opening to place the central passageway  49  of the filter body  46  in fluid communication with the bottom wall  36  and the threaded coupling portion  37  of the canister  30 . The bottom member  48  also forms a flange for supporting the depth filter  45  on the internal flange  38  of the canister  30 . 
     As shown in  FIGS. 15 and 16 , the filter body  46  has a substantially hourglass shape of upper and lower conical halves joined at a narrow center portion. This shape allows for filtration differentiation, i.e., the filtration characteristics of the filter body  46  will change across the length of the filter body  46  to provide different degrees of filtration across the length of the filter body  46 . In particular, the narrow center portion will filter only larger particles while the wide top and bottom portions of the filter body  46  will filter smaller particles. Accordingly, during use, the filter body  46  will clog first in the center portion and subsequently outwardly towards the top and bottom ends of the filter body  46 . It is to be appreciated that the depth filter  45  may be formed of any shape and material known to be suitable to those having ordinary skill in the art. For instance, the filter body  46  of the depth filter  45  may have a cylindrical shape. Further, it is to be appreciated that the depth filter  45  may be replaced with any type of filter known to be suitable to those having ordinary skill in the art that can be placed within the canister  30 . For instance, the canister  30  can be filled with a suitable particulate or aggregate filter media that is retained within the canister  30  and forms the depth filter  45 . 
     With reference to  FIG. 24 , according to an alternative embodiment of the present invention, the depth filter  145  includes a filter body  146  having a cylindrical, rather than hourglass, shape. The filter body  146  is made from meltblown polypropylene throughout and has an internal sidewall, which defines a central passageway  149  extending through the filter body  146  from a top end to a bottom end of the filter body  146 . The depth filter  145  also includes a top member  147  that closes the top end of the central passageway  149  of the filter body  146  and a bottom member  148  having an annular shape, which defines a bottom opening to place the central passageway  149  of the filter body  146  in fluid communication with the bottom wall  36  and the threaded coupling portion  37  of the canister  30 . The bottom member  148  also forms a flange for supporting the depth filter  145  on the internal flange  38  of the canister  30 . 
     With reference to  FIGS. 1-3 , the filter assembly  10  is assembled by positioning the depth filter  45  within the canister  30  such that the bottom member  48  of the depth filter  45  rests on the internal flange  38  of the canister  30 . When a pump  210  for the circulation system  200 , discussed below with reference to  FIG. 19 , is activated, the suction from the pump  210  will pull the depth filter  45  down into the canister  30  toward the bottom wall  36  of the canister  30  such that the bottom member  48  of the depth filter  45  sealingly engages the bottom wall  36  of the canister  30  and water is drawn through the filter body  46  to be filtered. 
     The top filter assembly  15  is then positioned on top of the canister  30  while the tabs  25  on the connection portion  24  of the bottom end member  22  of the top filter assembly  15  are aligned and engaged with the vertical portion of the L-shaped grooves  35  formed in the interior surface of the top lip  33  of the canister  30 , such that the bottom end member  22  rests upon the top lip  33  and the connection portion  24  of the bottom end member  22  extends into open top end of the canister  30 . The top filter assembly  15  is then rotated clockwise about its longitudinal axis relative to the canister  30  such that the tabs  25  on the connection portion  24  of the bottom end member  22  of the top filter assembly  15  engage with the horizontal portions of the L-shaped grooves  35  such that the top filter assembly  15  is vertically secured to the canister  30 . The protrusion  23  on the bottom end member  22  is positioned relative to the tabs  25  and the protrusion  34  on the top lip  33  of the canister  30  is positioned relative to the grooves  35  such that pin holes in the protrusions  23 ,  34  are aligned. The body  12  of the lock pin  11  is then inserted through the pin holes in both protrusions  23 ,  34  to secure the top filter assembly  15  and the canister  30  from being rotated relative to each other and disengaging the tabs  25  from the grooves  35 . 
     During use of the filter assembly  10 , water will flow radially through the pleated filter  16  of the top filter assembly  15 , which filters particles and debris from the circulating water, and into the hollow core  20  of the top filter assembly  15  via the perforations  21  in the hollow core  20 . The water then flows downward through hollow core  20  of the top filter assembly  15  and the bottom opening  26  in the bottom end member  22  into the hollow interior  32  of the canister  30 . Once within the hollow interior  32  of the canister  30 , the water will then flow radially through the filter material of the filter body  46  of the depth filter  45 , which further filters particles and debris from the circulating water, and into the central passageway  49  of the filter body  46 . Water flows out of the central passageway  49  via the opening in the bottom member  48  of the depth filter  45  and then out of the canister  30  via the threaded coupling  37  into the circulation system  200  of the spa. Accordingly, the filter assembly  10  provides for dual filtering of the water circulating through the circulation system  200 . The filter layer  16  of the top filter assembly  15  acts as a primary filter for removing larger debris and particles from the water. The depth filter  45  acts as a secondary filter for removing fine particles and contaminants from the water. 
     The filter assembly  10  is removable from the spa tub and may be disassembled by removing the lock pin  11  and rotating the top filter assembly  15  counterclockwise and lifted away to disengage the tabs  25  from the grooves  35 . The hollow interior  32  of the canister  30  can then be accessed for removal and replacement of the depth filter  45 . The filter layer  16  of the top filter assembly  15  may be sprayed with water to remove any debris trapped thereon. Further, because the depth filter  45  is removable from the canister  30 , the filter body  46  may be separately cleaned and disinfected, thus prolonging the operational lifetime of the depth filter  45 . According to an embodiment of the present invention, the top filter assembly  15  has an operational lifetime of 18-24 months and the depth filter  45  has an operational lifetime of 3-4 months. 
     With reference to  FIG. 19 , a schematic view of a water circulation system  200  of a spa tub is shown. The water flowing from the basin of the tub first passes into a filter chamber, which contains the filter assembly  10 . Due to pressure within the filter chamber, water is then caused to flow into the filter assembly  10  in a radial path through the filter layer  16  of the top filter assembly  15 , where larger debris and particles are filtered from the water and subsequently through the depth filter  45 , where fine particles and contaminants are additionally filtered from the water. A filter outlet conduit  201  is threadably coupled to the threaded coupling portion  37  at the bottom end of the canister  30  of the filter assembly  10 . The filter outlet conduit  201  is coupled to the threaded coupling portion  37  such that the filter assembly  10  is removable from the circulation system  200  and the filter chamber for cleaning, maintenance, and replacement. 
     Filtered water flows through the outlet conduit  201 , which is joined to a pump inlet conduit  203  and to a circulation pump  210  via the pump inlet conduit  203 . The circulation pump  210  is responsible for controlling the circulation of water into the basin via both the jet nozzles and waterfalls, or similar features. Filtered water directed to the basin and passing through one or more waterfalls or similar features is pumped by the circulation pump  210  through a pump outlet conduit  211  directly to the waterfall, as indicated by arrow A. Filtered water directed to the basin and passing through the jet nozzles is first directed to a water heater  220  via a pump outlet conduit  212 , branching away from the pump outlet conduit  211 . The heater  220  operates to heat the filtered water to a desired temperature before the water is directed through the jet nozzles. Filtered, heated water is then directed through a conduit  221  to a flow switch  230  for controlling the flow of water into the basin via the jet nozzles. After passing through the flow switch  230 , the water passes through a conduit  231  to one or more outlets  240 , which are coupled to the jet nozzles, which direct the water into the basin, according to techniques known to those of ordinary skill in the art. It is to be appreciated that while the filter assembly  10  has been described as being incorporated into a water circulation system  200  for a spa tub, the filter assembly  10  could be adapted to filter water in other circulation systems, for instance, the circulation system for a pool. 
       FIGS. 20-23  illustrate the performance of the filter assembly  10  and various components thereof with respect to pressure v. flow, i.e., the pressure drop created by the components of the filter assembly  10  both together and alone, and turbidity. During a turbidity test, the filter assembly  10 , according to the above embodiment of the present invention, was left running while 30 grams of silica sand were dumped into 40 gallons of water. The filter was then operated with water running through the filter assembly until the filter became loaded with sand. During the test, the turbidity levels of the water were checked every five to ten minutes. The measured turbidity level of the water over time as the water was continually filtered by the filter assembly is shown in  FIG. 22  by the line having diamond-shaped data points. This test demonstrates the effectiveness and operability of the filter, as the filter should steadily continue to reduce turbidity in the water until the reading reaches zero. As can be appreciated from  FIGS. 20-23 , the combination of the depth filter  45  and top filter assembly  15  is able to clean debris and contaminants from circulated water much more quickly than a pleated fabric depth filter acting alone. 
     While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. The presently preferred embodiments described herein are meant to be illustrative only, and not limiting as to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof.