Abstract:
A fluid treatment device includes a tank containing a fluid treatment medium and a fluid. A distributor plate is received in the tank and separates the bed from a lower end portion of the tank. A baffle is positioned beneath the distributor plate and is configured to direct fluid exiting a riser tube of the fluid treatment device toward the peripheral of the tank to thereby provide a more evenly-distributed flow through the radius of the distributor plate and through the fluid treatment medium. The baffle may have a downwardly facing concave surface that traps air bubbles generated during a brine draw operation.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention generally relates to fluid treatment system distributor plates and, more particularly, to a distributor plate assembly including a secondary baffle plate positioned beneath the primary distributor plate of such a system. 
     2. Discussion of the Related Art 
     Water softeners are widely used for removing calcium and other deposit causing materials from so-called “hard-water.” The typical water softener relies on an ion exchanges process taking place in an ion-exchange resin bed stored in a resin tank or pressure vessel of the water softener. As the water to be processed passes through the resin-filled tank, ions of calcium and other minerals in the water are exchanged with ions found in the resin, e.g., sodium, thereby removing objectionable ions from the water and exchanging them for less objectionable ions from the resin. 
     The capacity of the resin to exchange ions is finite and is reduced during the ion exchange process. If measures are not taken to regenerate the resin by replacing the undesirable ions with desirable ions, the ion exchange capacity of the resin will become exhausted. Water softeners are typically configured to periodically regenerate the ion exchange resin stored in the resin tank. Regeneration typically involves chemically replacing the objectionable ions such as calcium ions from the resin with less objectionable ions such as sodium ions. The replacement is usually performed by introducing a regenerant solution of sodium chloride or potassium chloride into the resin bed from a brine tank and thereafter flushing the regenerant solution from the bed, i.e., brining. Regeneration of a water softener resin bed is sometimes accomplished in a direction that is co-current with the flow of water to be treated (often referred to as “downflow regeneration” or “service flow”) and is sometimes accomplished in a direction countercurrent to the flow of the water being treated (often referred to as “upflow regeneration” or “backwash flow”). The resin bed is typically backwashed in order to remove trapped particulate matter, and the resin tank can be rinsed to remove objectionable soluble materials. In order to prevent interruption of service, most water softeners are configured to allow bypass of untreated water directly to the service lines during backwash, rinse, and regeneration. 
     Resin tanks typically employ a distributor plate that allows water to flow through either a filter media bed or an ion exchange bed. Such distributor plates are configured to distribute flow as evenly as possible across the bed to ensure that the entirety of the bed is treated. However, such distributor plates do not operate as efficiently as is desired, particularly in resin tanks employing an upflow brining system. Upflow brining involves forcing water from the brine tank downward through a central riser tube to the bottom of the resin tank and then upward, i.e., upflow, through the distributor plate and the resin bed and out of the top of the tank. 
     During the brining operation, and particularly the brine draw operation where the brining solution is drawn up through the resin bed, gasses trapped in the fluid are disassociated and form bubbles, which float up through the distributor plate. The bubbles tend to float directly up near the centrally located riser tube and form channels through the resin bed media through which fluid tends to flow, effectively short circuiting the flow of brine past the media. 
     Further, after the brining process is complete, a slow rinse phase occurs, which is configured to remove excess brine from the resin bed. In the slow rinse phase, raw, untreated water (or, in some systems, treated water) is delivered to the lower end of the resin tank by the riser tube. However, as the rinse water exits bottom of the riser tube, it tends to immediately percolate up through the distributor plate along the riser tube rather than flowing out toward the edge of the tank. This concentrated flow near the riser tube results in the water being concentrated near the center of the tank, leading to insufficient rinsing of media located near the outer edge of the tank. 
     At least some of these issues are not unique to resin tanks of water conditioning system but, instead, are of a concern in a variety of fluid treatment systems in which a treatment medium is subject to brining. 
     The need therefore exists to provide a resin tank configured to more uniformly distribute water or other fluid across the entirety of the resin tank during a brining phase and/or a slow rinse phase of an upflow brining process. 
     SUMMARY OF THE INVENTION 
     In accordance with a first aspect of the invention, a fluid treatment device is provided that includes a tank containing a bed of fluid treatment media and a fluid. A distributor plate is received in the tank and separates the bed from a lower end portion of the tank. A secondary plate or baffle is positioned beneath the distributor plate. The baffle is configured to direct a rinsing fluid delivered to the lower end around an edge of the baffle to improve flow distribution radially across the tank. The baffle may have a downwardly facing concave surface configured to trap air bubbles generated, for example, during the brining phase of a media regeneration cycle. 
     The baffle may extend radially approximately halfway between a hub of the distributor plate and an outer edge of the tank. The baffle may be positioned, relative to vertical, about halfway between a bottom of the tank and an underside of the distributor plate. 
     In accordance with another aspect of the invention, a method of operating a fluid treatment device comprises delivering a fluid to a lower end portion of a resin tank through a centrally located riser tube. The method further comprises diverting the fluid outwardly from the riser tube with a baffle positioned beneath the distributor plate to thereby distribute the fluid radially across the tank. The method may also comprise trapping air bubbles beneath a concave bottom surface of the baffle. 
     Various other features, embodiments and alternatives of the present invention will be made apparent from the following detailed description taken together with the drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration and not limitation. Many changes and modifications could be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings, in which like reference numerals represent like parts throughout, and in which: 
         FIG. 1  is a sectional side elevation view of a bottom portion of a pressure vessel according to the prior art and is appropriately labeled “PRIOR ART”; 
         FIG. 2  is a sectional side elevation view of a pressure vessel including a secondary plate according to an aspect of the present invention; 
         FIG. 3  is a sectional bottom plan view of the pressure vessel taken from beneath the secondary plate; 
         FIG. 4  is a sectional side elevation corresponding to  FIG. 2  and additionally illustrating a guard coupled to the secondary plate; and 
         FIG. 5  is a partial sectional side elevation view showing the secondary plate and guard in additional detail. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings and, initially,  FIG. 1 , a prior art resin tank  10  used in a water treatment system (not shown). One of a variety of water treatment systems with which the resin tank  10  is usable is disclosed in U.S. Pat. No. 6,402,944, the contents which are incorporated herein by reference. The tank  10  includes a blow-molded plastic liner  33  reinforced by a layer  34  of fiberglass wrap or the like. The interior of the tank  10  contains a resin bed  12  separated from a lower end portion  14  of the tank  10  by a distributor plate  16 . The distributor plate  16  comprises a central hub  18  through which a distributor or riser tube  20  is securely received such that the distributor plate  16  is capable of supporting the riser tube  20 . The distributor plate  16  further includes an outer ring  22 , which is bonded to the interior wall of the resin tank liner  33  forming the outer edge of the tank  10 . A slotted plate  24 , supported by a number of reinforcing ribs  40 , is provided between the hub  18  and the outer ring  22  and is configured to allow water to pass through the distributor plate  16  between the resin bed  12  and the lower end portion  14  of the tank  10 . The distributor plate  16  may be integrally constructed from a plastic or similarly suitable material. The hub  18  defines a flange  25  which extends downwardly from an upper surface of the distributor plate  16 . The flange  25  may include a threaded portion  26  configured to engage a corresponding threaded portion  28  on the bottom  30  end of the riser tube  20 . An inlet tube  32 , positioned beneath the bottom end  30  of the riser tube  20 , extends downwardly through the distributor plate  16  in communication with the lower end portion  14  of the tank  10 . 
     As is generally understood in the art, in upflow brining, a brine solution is passed down the riser tube  20  to the lower end portion  14  of the resin tank  10 . The brine then flows upwardly through the distributor plate  16  and then through the resin bed  12  and eventually out of the resin tank  10 . Because the brine solution is heavier than water, the brine solution tends to puddle or pool underneath the distributor plate  16 . With the relatively low velocities involved with pushing the brine solution up through the distributor plate  16  and the resin bed  12 , a portion of the brine solution begins to puddle or pool underneath the distributor plate  16  after all of the brine solution has been delivered to the lower end portion  14  of the tank  10 . Further, during the delivery of the brine solution to the lower end portion  14 , gasses trapped in the water are disassociated and form air bubbles  39 . These bubbles  39  float up through the resin bed  12  and create channels along the riser tube  20  through which the brine solution may be preferentially directed, which thereby prevents or at least inhibits the brine solution from reaching the outer edge of the resin tank  10 . 
     After the brine solution is delivered to the resin bed  12 , the fluid treatment system operates in a so-called “slow rinse” phase of the water treatment cycle to clear any remaining brine solution from the resin tank  10 , typically using untreated or raw water, or in some cases treated water, both of which have a lower density than the brine remaining in the tank. Because the slow rinse water is less dense in prior art fluid treatment systems such as that shown in  FIG. 1 , the water for the slow rinse phase begins to percolate directly upwardly near the distributor plate  16  almost immediately upon leaving the riser tube  20  and thus does not get evenly distributed across the radius of the resin tank  10 , thereby resulting in less effective or even ineffective rinsing of the resin in the outer portions of the tank. 
     In particular, as indicated by arrows  36 , during the slow rinse phase, water is introduced into the lower end portion  14  of the tank via the riser tube  20  and the inlet tube  32 . The water flows out of the end of tube  32  and, as indicated by the arrows  38 , immediately begins to rise nearly vertically upwardly near the distributor plate  16 . Thus, the water is heavily concentrated near the riser tube  20  as indicated by arrows  41 , resulting in an inefficient rinsing of the outer portion of the resin bed  12 . Even this flow is hindered by the “unrinsed brine” accumulated on the bottom of the tank during the brining operation as shown at  37 . 
     With reference now to  FIGS. 2-3 , a resin tank  110  is shown in accordance with an embodiment of the invention. Resin tank  110  and the associated distributor plate  116  are of generally the same construction as the corresponding components of the prior art resin tank  10  of  FIG. 1  except for the fact that a secondary plate or baffle  142  is provide beneath the primary distributor plate  116 . Since many of the structures and features of the resin tank  110  are identical to those of the resin tank  10  of  FIG. 1 , the foregoing descriptions thereof apply equally unless otherwise indicated. The reference numerals of the structures of  FIG. 1  are incremented by 100 in  FIGS. 2-5 . 
     The secondary plate or baffle  142  is positioned vertically between the bottom surface of the tank  110  and distributor plate  116 . It may be mounted directly or indirectly on the hub  118  of the distributor plate  116 , the bottom of the tank  110 , or the tank liner  133 . It is indirectly mounted on the hub  118  in this embodiment by being coupled to the inlet tube  132 . Hence, the baffle  142  may be coupled to inlet tube  132  or may be integrally formed therewith as shown. At least the bottom surface  143  of the baffle  142  is concave so as to face downwardly. The baffle  142  may also include a mounting ring  150  integrally formed and extending from the bottom surface  143  thereof. The mounting ring  150  may be configured to receive an accessory as will be described in additional detail herein. 
     As will be explained in additional detail hereinafter, the distributor plate  116  may include a port  151 , which may be provided to allow an operator of the tank  110  to fill the lower end portion  114  of the tank  110  with an inert particulate media as discussed below. 
     The diameter of the baffle  142  is selected so as to position its circular outer edge  145  at a location that results in directing some fluid toward the outer edge of the tank  110  while still assuring that enough fluid flows up the inner portion of the resin bed  112  to achieve the desired relatively uniform flow throughout the radius of the resin bed  112 . The ideal baffle diameter will depend on a number of factors including, but not limited to, the density, viscosity, and flow rate of the fluid, as well as the vertical spacings between the baffle  142  and the bottom of the tank  110  and between the baffle  142  and the bottom of the distribution plate  116 . In a preferred construction of the baffle  142 , the outer edge  145  of the baffle  142  is positioned between 20% and 80%, more preferably 40% to 70%, and most preferably approximately halfway between the flange  125  of the hub  118  and outer edge of the tank  110  as defined by the inner surface of the liner  133 . Further, in a preferred construction of the baffle  142 , the concavity of the baffle  142  is sized to define a volume of sufficient size to accommodate a worst-case scenario with respect to the amount of bubbles  139  that may be formed during the brining process so as to be capable of at least substantially entirely capturing the bubbles  139 . 
     The baffle  142  may be spaced in any number of positions relative to vertical with respect to the distributor plate  116 . For a given baffle diameter, the nearer to the distributor plate  116  that the baffle  142  is positioned, the better the baffle  142  is able to trap the bubbles  139 , whereas the nearer to the bottom of the tank  110  the baffle is positioned, the better the baffle is at redirecting the water or fluid toward the outer edges of the tank  110  to better distribute the fluid from the slow rinse cycle evenly across the radius of the tank  110 . In the illustrated embodiment in which diameter of the baffle  142  is about half that of the tank  110 , the baffle  142  is positioned approximately halfway between the bottom of the distributor plate  116  and the bottom of the tank  110 . 
     In operation, during the slow rinse phase, the water is delivered to the lower end portion  114  of the tank via the riser tube  120  and the inlet tube  132  as indicated by the arrows  136 . However, unlike in the prior art systems, as the water exits the riser tube  120 , the water is forced outwardly toward the outer edge of the resin tank  110  as indicated by arrows  138 . As the water reaches the edge of the baffle  142 , it flows around the past the outer edge  145  of the baffle  42 . From there some of the water flows toward the riser tube  120  and the center of the resin tank  110 , and some is diverted toward the outer edge of the resin tank  110  as illustrated by arrows  152 . In this manner, the water used for the slow rinse cycle is more evenly distributed across the entire radius of the resin tank  110  as illustrated by arrows  141  and therefore is better able to entirely rinse the resin bed  112  of the brine solution. Further, as opposed to the prior art, the air bubbles  139  are caught underneath the baffle  142  and thus at least substantially prevented from floating up toward the distributor plate  116 , thus preventing the formation of a channel through the resin bed  112  through which the water or other fluid may flow. The bubbles  139  may then be subsequently removed during the so-called “fast rinse” phase of the water treatment cycle. 
     With reference now to  FIGS. 4 and 5 , another embodiment of the present invention is illustrated. In the present embodiment, the structures of the tank  210  are identical to those of the first embodiment illustrated in  FIGS. 2 and 3  unless otherwise indicated, and the structures are numbered as in  FIGS. 2 and 3  and incremented by 100. 
     In the present embodiment, the distributor plate  216  and the baffle  242  are of identical construction to the corresponding components of the first embodiment. In addition, the lower end portion  214  of the tank  210  is filled with an inert media, generally shown as numeral  254 . The media may be introduced to the lower end portion  214  via the port  251  in the distributor plate  216  corresponding to the port  151  of the first embodiment (see  FIG. 3 ) after installation of the plates  216 ,  242  and related components into the tank  210 . Alternatively the inert media may be inserted prior to installation of the plates  216 ,  242  and related components. In either case the case, the port  251  is plugged after insertion of the inert media to prevent unwanted matter from moving through the distributor plate  216  in either direction. 
     Preferably, substantially the entirety of the volume of the tank  210  beneath the distributor plate  216  is filled with the inert media  254  in order to minimize the volume where brine will be trapped during operation. Accordingly, the inert media may be either heavier than or lighter than the fluid of the fluid treatment tank. The inert media  254  is preferably granular and may be in the form any or all of gravel, polypropylene beads, polyethylene beads, etc. The inert media  254  thereby minimizes and reduces the void volume beneath the bottom the distributor plate  216 . Since the volumetric flow rate of rinse water is the same (typically about 2.5 gallons per minute) whether or not the inert media is present in the bottom portion of the tank, the presence of the media causes the rinse water through flow in the bottom portion  214  of the tank  210  at a higher velocity, improving the flushing of unrinsed brine from the bottom portion  214  of the tank  210  and improving the rinse phase overall. 
     A guard  256  may be coupled to the mounting ring  250  of the baffle  242 . The guard  256  is configured to protect the bottom of the inlet tube  232  from the ingress and egress of the inert material  254  during operation. The guard  256  may be sized and shaped in any manner so long as the guard  256  is capable of preventing the intrusion of the inert media  254 . As illustrated, the guard  256  is generally frusto-conically shaped and includes a relatively flat bottom  258 , a circumferential sidewall  260  having a plurality of apertures, holes, or other such openings  262  to allow for fluid flow therethrough, and a flanged upper end  264 , which is configured to be coupled with the mounting ring  250 . The openings  262  of the guard  256  preferably are sized and shaped to prevent the inert media  254  from entering the guard  256  and, thereby, the inlet tube  232  and the riser tube  220 . The guard  256  may be integrally molded with the mounting ring  250  or connected to the mounting ring  250  by any other suitable mechanism. 
     Although the best mode contemplated by the inventors of carrying out the present invention is disclosed above, practice of the present invention is not limited thereto. It will be manifest that various additions, modifications and rearrangements of the aspects and features of the present invention may be made in addition to those described above without deviating from the spirit and scope of the underlying inventive concept. The scope of some of these changes is discussed above. The scope of other changes to the described embodiments that fall within the present invention but that are not specifically discussed above will become apparent from the appended claims and other attachments.