Abstract:
A dispense device includes a dispense head and threaded canister. A chemical container assembly disposed within the canister includes a support column which telescopically receives a chemical container. The chemical container includes inlet and outlet holes to allow a flow through the container to come into contact and subsequently dissolve chemical treatment material disposed within the container. The support column engages the dispense head to aid in defining the separation distance between the dispense head and the outlet hole of the chemical container.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a continuation-in-part of U.S. patent application Ser. No. 09/442,935 filed Nov. 18, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to the chemical treatment of liquids, such as water for food processing and other uses. 
     2. Description of the Related Art 
     Many commercial and residential water supplies suffer from “hard water” and other objectionable conditions. Oftentimes, remedial measures are implemented with the addition of chemical treatments to the water supply. In order to provide effective treatment and to prevent other problems from occurring, it may be necessary to carefully meter the amount of chemical treatment agent to a given quantity of supplied water. 
     A liquid treatment apparatus as described in commonly assigned U.S. Pat. No. 5,507,945 has proven commercially successful, particularly in the treatment of water supplies used for food preparation and other applications. The liquid treatment apparatus provides a chemical treatment agent which is put into solution and mixed with water flowing through the apparatus. More particularly, the liquid treatment apparatus includes a dispense head which develops a venturi action which is applied so as to help meter relatively small amounts of treatment chemical in the fluid flow. The liquid treatment apparatus includes, in addition to the aforementioned dispense head, a canister which threadingly engages the dispense head and which receives a container holding the chemical agent. The dispense head is typically joined to a piping system and has means for attachment to a mounting bracket if additional support is required. In operation, the canister is unthreaded from the dispensing head to allow replenishment of the chemical treating agent, as may be required. While the chemical treatment apparatus has been met with widespread commercial acceptance, it is desirable to provide low cost alternative systems which can be made operational by a simple retrofit to existing equipment, such as pre-filter housings, which are easily implemented by operators who are not familiar with dispenser and fluid metering technologies. 
     U.S. Pat. No. 5,580,448 discloses a chemical dispenser having a cartridge, used either alone or with an outer surrounding filter sleeve. The cartridge includes an apertured mid-section located between an upper solid wall conduit segment and a lower chemical-containing cartridge member which includes a dispensing aperture at its upper end. Thus, the amount of chemical treatment agent which can be provided, is reduced by the amount of the combined volume of the solid wall conduit segment and the apertured mid-section. Improvements to cartridges of this type are continuously being sought. 
     In various types of commercial activities, such as produce handling, food stores and restaurants, the available domestic water supply is employed to carry out commercial operations. Remedial measures to address problems of corrosion and scaling, are sometimes carried out with the introduction of small amounts of a treatment chemical, such as polyphosphate or sodium silicate, into the domestic water supply. Operators of the commercial establishments may not have the time or training required to appreciate the subtle operations of the chemical dispensing systems which are relied upon to control various water supply problems. It is advantageous to provide water treatment apparatus which is readily understood and easily maintained by operators of commercial establishments and other members of the community requiring water treatment. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide chemical treatment apparatus for introducing relatively small amounts of a treatment chemical into a liquid supply. 
     Another object of the present invention is to provide a liquid treatment apparatus of the type which meters a treatment chemical into a liquid flow. 
     A further object of the present invention is to provide liquid treatment apparatus which can be integrated with a conventional plumbing system to meter a treatment chemical into a domestic water supply delivered by the plumbing system. 
     Yet another object of the present invention is to provide liquid treatment apparatus of the above-described type having a replaceable cartridge. 
     A further object of the present invention is to provide liquid treatment apparatus of the above-described type having an improved cartridge insert offering an enhanced reliability of operation. 
     These and other objects of the present invention are provided in apparatus for insertion into a liquid flow line for dispensing a soluble chemical into the liquid flowing through the flow line comprising: 
     a dispense head member including an inlet and an outlet and defining a flow passageway coupling the inlet and the outlet; 
     a canister; 
     said dispense head flow passageway including flow entry means for directing fluid flow into said hollow interior cavity and flow exit means for directing fluid flow out of said hollow interior cavity; 
     the dispense head member and the canister having cooperating means for removably attaching the dispense head to the canister; 
     a chemical holding container adapted to fit within said canister; 
     said chemical holding container having opposed upper and lower ends and defining inlet and outlet flow pathways at its upper end; and 
     said chemical holding container further including a cap comprising a unitary monolithic body having a center portion defining socket means for connection to said dispense head so as to bring said outlet flow pathway of said chemical holding container in flow communication with the flow passageway of said dispense head. 
     Other advantages are provided in a dispensing device for dispensing a chemical agent into a fluid flow, comprising: 
     a dispense head having inlet and outlet means for coupling to said fluid flow and defining a flow passageway coupling said inlet and said outlet means; 
     a canister engageable with said dispense head and defining a hollow interior cavity; 
     said flow passageway in said dispense head including flow entry means for directing fluid flow into said hollow interior cavity and flow exit means for directing fluid flow out of said hollow interior cavity of said canister; 
     a chemical holding container within said hollow interior cavity of said canister, in contact with the fluid flow; 
     said chemical holding container having a tubular body with opposed upper and lower ends and defining a hollow, chemical-receiving interior; 
     said tubular body including an inlet aperture portion adjacent its upper end; and 
     a cap enclosing the upper end of said tubular body, said cap comprising a unitary monolithic body having a center portion defining socket means extending into said tubular body hollow interior and providing at least one outlet aperture for flow connection to said flow exit means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a dispensing apparatus; 
     FIG. 2 is a cross-sectional vies thereof taken along the lines  2 — 2  of FIG. 1; 
     FIG. 3 is a fragmentary elevational view of the cartridge insert of FIG. 2; 
     FIG. 4 is a cross-sectional view showing the upper portion of FIG. 2 on an enlarged scale; 
     FIG. 5 is a fragmentary cross-sectional view showing the bottom portion of FIG. 2 on an enlarged scale; 
     FIGS. 6-8 show alternative embodiments of the bottom construction of the dispensing apparatus; 
     FIG. 9 is a fragmentary cross-sectional view of a prior art cartridge assembly; and 
     FIGS. 10-13 show alternative embodiments of cartridge assemblies shown installed in a cartridge housing. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIGS. 1-4, a dispensing device according to principles of the present invention is generally indicated at  10 . The dispensing device  10  comprises a fluid-tight, preferably pressure-tight vessel or housing  11  comprising a dispense head  12  and a sump or canister  14 . As can be seen, for example in FIG. 4, the dispense head and canister have interfitting threaded portions  16 ,  18 , respectively. A conventional O-ring seal  20  is the preferred mode of providing leak-free joiner of the dispense head and canister. 
     Referring to FIGS. 2 and 4, the dispense head  12  is preferably of monolithic molded plastic design. An inlet  24 , preferably threaded, accepts a pressurized fluid flow indicated by the arrow  26 . Incoming flow enters through an internal hole  28 , into the interior  30  of the canister  14 . The incoming flow fills the entire interior of canister  14  and eventually exits through a flow exit means in the form of a stub portion or projection  34 , through outlet passageway  36 , entering main bore  38  and passing through threaded outlet opening  40 , as indicated by arrow  42 . As can be seen in FIGS. 2 and 4, the projection  34  comprises a stub-like nipple projecting beyond the bottom wall  44  of dispense head  12 , and slightly beyond annular wall  46 , into the hollow cavity of canister  14 . 
     Dispense head  12  can take on configurations other than that illustrated in the figures. For example, the present invention can be employed with existing pre-filter housings to provide a retrofit upgrade which adds chemical treatment to the fluid being processed. Further benefits are enjoyed by the present invention in that maintenance operations, oftentimes carried out by a store operator who implements a familiar service routine, similar to that of replacing a filter element. With the present invention, metering accuracies previously associated with venturi-type dispensing heads can now be enjoyed with dispensing heads of a simplified pre-filter type. 
     Preferably, the present invention provides flow regulation for dispensing devices which are pressure-induced, rather than relying on the suction effects of venturi flow, as in earlier designs. However, since it may also be expedient at times to incorporate the present invention with dispensing devices of the venturi flow type, the present invention also provides a chemical container assembly (to be described below) which can be readily employed with venturi devices, such as the venturi-type cap  48  as disclosed in commonly assigned U.S. Pat. No. 5,507,945, which is herein incorporated by reference. 
     Referring to FIGS. 2 and 3, dispensing device  10  further includes a chemical container assembly generally indicated at  50 . Chemical container assembly  50  includes a hollow tubular body  70  enclosed at its upper and lower ends by end caps  74 ,  76 , respectively. The upper end of the chemical container assembly has inlet and outlet flow pathways formed by one or more holes in the end cap  74  and tubular body  70 . In the preferred embodiment, a linear series of three holes  80  are formed in the underlying, upper end of tubular body  70 . Preferably, the holes  80  are aligned generally parallel to a central axis of the chemical container tubular body. Holes  80  allow introduction of surrounding fluids to enter the hollow interior of tubular body  70 , so as to contact the treatment chemical  82 . If desired, the holes  80  can extend to holes formed in end cap  74 . Preferably, however, a single large aperture or hole  81  is formed by edge  83  in upper end cap  74  so as to expose an inlet aperture portion  70 a of tubular body  70  surrounding holes  80 . Aperture  81  allows incoming fluid flow unobstructed access to holes  80  formed in tubular body  70 . The length of the passageway at fluid must travel to enter the interior  72  of body  70  is significantly reduced compared to prior art arrangements, such as that shown in FIG. 9, where holes  120  pass continuously through upper end cap  122  and body wall  124  of a dispense apparatus  130 . 
     Referring now to FIG. 9, it can be seen that the prior art upper end cap assembly includes a plug  130  received in a central aperture formed in the wall  134  of end cap  122 . The central hole in wall  134  is formed by a drilling operation using a conventional hole saw. As indicated in FIG. 9, the plug  130  is considerably thicker than the wall  134  of end cap  122 , and is seated with a friction fit with the flange  136  of the plug  130  being seated against wall  134 . It has been observed that prior art end cap assemblies of the type illustrated in FIG. 9 undergo a deformation, with the wall  134  being dished to form a concave recess facing the dispense head  12 . As shown in FIG. 9, this results in a gap  140  being formed between flange  136  and annular ring  46  of the dispense head. This results in a leakage path whereby incoming fluid is allowed to bypass the interior of body  124  avoiding contact with the chemical treatment located therein. Because of the relatively short leakage path localized at the top of the chemical cartridge, severe conditions may be set up within the dispensing apparatus whereby flow through tubular body  124  is reduced, further contributing to an undesirable lowering of chemical injection rates and lower chemical concentrations at the outlet  40  of dispense head  12 . 
     The causes leading to distortion of end cap  122  are not fully understood at this point in time, but is believed to be attributed to the drilling operation formed in the center of wall  134 . It is believed that, even if the central hole in wall  134  were formed by other means such as hot knife cutting, a buckling distortion in wall  134  would still result. It is suspected that internal strains and stresses are stored within end cap  122  at the time of its manufacture and that forming a relatively large size central hole, such as that depicted in FIG. 9, releases some of the stresses in the end cap  122  resulting in non-uniform stresses residing in the end cap, tending to distort wall  134 . 
     Returning again to FIGS. 2-4, end cap  74  has a unitary monolithic construction including end wall  150 , central stub wall  152  and center wall  154 , in addition to an outer wall  156 . Except for hole  81  (see FIG. 3) formed in outer wall  156  and relatively small diameter outlet holes  160  formed in center stub wall  152 , no holes or other openings are formed in end cap  74 . As can be seen for example in FIG. 2, the outlet holes formed at the bottom of central stub wall  152  are of relatively small diameter, of the same relative magnitude as the thickness of the stub wall. Preferably, the outlet holes  152  are formed to meet the requirements of a particular installation and depend, for example, on external factors such as the type of chemical required, and the fluid pressures applied to the dispensing apparatus. The outlet holes  160  are sometimes formed in an otherwise completely fabricated end cap, so s to allow for last minute adjustments to the performance of the metering system. The outlet holes formed in center stub wall  152  have a size, as mentioned, on the order of the thickness of the end cap and for most applications are sized no more than five to ten times the thickness of the end cap, a size much smaller than central apertures formed in prior art end caps, for receiving the stub projection  34  of dispense head  12 . Further, unlike the central holes drilled in prior art end caps, outlet holes  160  are formed in longitudinally extending portions of the end cap (i.e., are formed in axially extending center stub walls  152 ), rather than transversely extending end walls (such as end wall  150  of end cap  74 ), so as to avoid buckling deformation. 
     In addition to avoiding compromise of end wall  150 , end cap  74  is provided with the central stub wall  152  and center wall  154  which function as a central reinforcement for end wall  150 . As can be seen for example in FIG. 4, the stub protrusion  34  extends into the central bore of the stub wall  152  and the close tolerance fit between stub wall  152  and stub portion  34  can be dimensioned so as to provide support at the center of the end cap, while avoiding inward axially directed deformation forces applied to the end cap by the stub portion  34  of the dispense head, as the dispense head is threadingly engaged with the canister  14 . 
     Referring again to FIG. 4, the bottom edges of annular wall  46  of the dispense head contact the upper outer surface of end wall  150  of end cap  74 . This provides a reliable sealing engagement between the dispense head and the cartridge assembly. Since dishing or cupping deformation of the end cap  74  is avoided, sealing engagement between the end cap and dispense head is assured. If desired, end cap  74  may be formed of material which provides a substantial bias force to augment the sealing contact between end wall  150  and stub portion  46  of the dispense head. 
     Preferably, the treatment chemical employed with the dispensing device comprises a solid cake but may also take the form of a loose or compressed powder, a molded solid, or a gel, for example. In the preferred embodiment, the dispensing device  10  is employed for the treatment of water supplies with the chemical agent comprising a cake  82  of polyphosphate material. The treatment chemical is gradually dissolved by water filling the interior of canister  14  and entering the chemical container through holes  80 . The dissolved treatment chemical passes through an outlet hole  86  formed in the center of cap  74 , so as to combine, as indicated in FIG. 2, with the outlet fluid flow indicated by arrow  42 . An optional outlet nozzle or jet  84  may be mounted in the hole  36  in upper end cap  74 , although this has not been found to be necessary. 
     As can be seen at the bottom of FIGS. 1 and 3, for example, canister  14  is provided with an upstanding alignment post  96 . Post  96  extends into the interior of the container cavity to help orient the bottom of the chemical container assembly. In the preferred embodiment, a bottoms mounting cup  52  is employed with a central upraised portion which is telescopically fittable over post  96 . Referring to FIGS. 6-8, alternative bottom treatments for cartridge assembly  50  are shown. In FIG. 6, a featureless cylindrical end cap  150  is shown mated against a flat bottom wall of a canister  152 . In FIG. 7, end cap  150  is shown butted against alignment post  96 . In FIG. 8, a lower end cap  160  is shown mated with alignment post  96 . Bottom end cap  160  generally resembles upper end cap  74 , except for the absence of holes, as flow communication is not required at the bottom portions of the chemical cake  82 . 
     Turning now to FIGS. 10-13, alternative embodiments, replacing the upper end cap  74 , are shown. In FIG. 10, an upper end cap  170  is substantially identical to upper end cap  74 , except for a thickened central portion formed by the addition of a stepped collar member  172 , preferably integrally formed with the remainder of the end cap. As indicated in FIG. 10, the outer corner of collar  172  mates with a chamfered end surface  174  of stub projection  46 . As can be seen in FIG. 10, two lines of sealing contact are formed between dispense head  12  and end cap  170 . 
     Turning the FIG. 11, an end cap  180  is substantially identical to end cap  74 , except for a thickened outer wall  182  having a bottom step portion  184  for receiving the upper free end of tubular body  70 . The stepped feature  184  of end cap  180  allows the tubular wall  70  to be cut flush with chemical cake  82 . Thus, a continuous bulk cake can be formed, and subsequently divided lengthwise, as needed at the time of manufacture of the chemical cartridge assembly. 
     Turning now to FIG. 12, an upper end cap  190  is substantially identical to upper end cap  74 , except for the addition of a thickened central portion, preferably formed with the addition of a frustoconical ring  192 . Preferably, frustoconical ring  192  is molded with the remainder of upper end cap  190 . As can be seen in FIG. 12, a frustoconical sealing band is provided at the overlapping mating joiner of frustoconical ring  192  and the internally chamfered surface  174  of dispense head projection  46 . 
     Turning now to FIG. 13, an upper end cap  200  is substantially identical to end cap  74 , except for chamfered corners  202  formed between stub wall  152  and center wall  154 . Chamfered corners  202  provide a positive stop, limiting the amount of insertion of dispense head projection  46 , and ensuring the desired chemical draw. 
     The drawings and the foregoing descriptions are not intended to represent the only forms of the invention in regard to the details of its construction and manner of operation. Changes in form and in the proportion of parts, as well as the substitution of equivalents, are contemplated as circumstances may suggest or render expedient; and although specific terms have been employed, they are intended in a generic and descriptive sense only and not for the purposes of limitation, the scope of the invention being delineated by the following claims.