Abstract:
A diluent such as water is sprayed from a nozzle through a screen onto water soluble packages of chemical supported on the screen to produce a solution for treatment of a system. The solution falls into a reservoir and is recirculated through the nozzle onto the screen for a duration sufficient to dissolve a load of chemical into solution. The concentrated solution is dispensed to a system. The reservoir can be flushed into the system before recirculating solution to the nozzle for further chemical dissolving. Chemical-containing packages can be loaded at any time without system interruption. Chemical is supplied in powder or solid form.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to the dispensing of chemical containing liquids and more particularly to apparatus and methods for preparing a liquid chemical solution from a powdered or solid chemical for dispensing. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the past, it has been known to prepare a liquid chemical solution from liquid, solid or powdered chemicals. For example, one form of preparing a dispensable liquid from a solid chemical product is disclosed in U.S. patent application Ser. No. 13/031,724 filed on Feb. 22, 2011 and entitled “SOLID CHEMICAL DISSOLVER AND METHODS”, which application is expressly incorporated herein by reference and is a part hereof. Other forms of dispensers are shown in U.S. Pat. Nos. 2,371,720; 3,383,178; 3,595,438; 4,858,449; 4,964,185; 5,137,694; 6,441,073; 6,418,958 and 6,820,661 and in U.S. Published patent applications as US2007/0269894 and US2010/0025338. Each of these patents and publications is expressly incorporated herein by reference and is a part hereof. 
         [0003]    Where it is desired to produce a dispensable, chemical containing liquid from chemicals in powdered form, as opposed to a liquid form, the powdered form chemicals may have several inherent disadvantages. For example, the powder may not be readily dissolvable in water. The powder may take a comparatively longer time to dissolve in water, as opposed to a liquid chemical form, in order to prepare a concentrated solution strong enough for any system which requires consistent doses. Prior devices thus typically feed a less concentrated solution, or use stronger, ready-made solutions. Some prior devices of the continuous feed variety require the powder dissolver to be turned off in order to recharge. Moreover, chemical concentrates in liquid form for use in the ready-made devices can be hazardous to handle with undesirable exposure consequences. 
         [0004]    Also, the dissolving of certain chemicals in powdered form can produce fumes which are at best unpleasant. 
         [0005]    Accordingly, it has been one objective of the invention to provide apparatus and methods for dissolving chemicals in powdered form to produce a dispensable liquid chemical concentrate solution in sufficient strength for use in a variety of treatment systems, particularly in those requiring small doses. 
         [0006]    Another objective of the invention has been to provide a chemical powdered dissolver which does not require stoppage in order to recharge. 
         [0007]    A related objective has been to produce a chemical powder dissolver which accommodates the addition of chemicals in powdered form without interruption of a dosing operation for which the dissolver is used. 
         [0008]    A further objective of the invention is to provide a chemical powder dissolver for receiving chemical powder in discrete packages for introduction intact into the dissolver and thus eliminating the chance of undesirable contact of the chemical with a human operator. 
         [0009]    A yet further objective of the invention has been to provide a chemical powder dissolver which prevents or substantially reduces the escape of gases from the powder dissolving process. 
         [0010]    In addition to the foregoing, it will be appreciated that even where the chemical is concentrated in a disk, pellet or other solid form, several of the above described problems may be presented, such as the difficulty in presenting, then dissolving the chemical pursuant to spray from a nozzle in order to produce a solution of sufficient concentration for use in treating a water system, for example. 
         [0011]    Accordingly, it has been yet a further objective of the invention to provide apparatus and methods for dissolving chemicals presented in either a powered or solid format into a dispensable solution of sufficient concentrate or strength for use in a variety of treatment systems. 
       SUMMARY OF THE INVENTION 
       [0012]    To these ends, a preferred embodiment of the invention includes a chemical container for receiving discrete water soluble packages of chemical in either powder or solid form. For one example, powdered biocides may be used as well as solid inhibitors. The packages rest on a support screen at least proximate to, and preferably at, the bottom of the container. A water spray nozzle is directed toward the screen, so that spray through the screen dissolves the packages, then the powder therein, with concentrated solution and any small, undissolved particles falling into a solution reservoir, which is initially full of fresh water. The solution in the reservoir is recirculated by a pump back to the nozzle and again sprayed through the screen onto the packages of powder and then with the chemical concentration of the solution increasing with time. 
         [0013]    The recirculation pump operates for a predetermined time duration sufficient to provide a dispensable solution of desired chemical concentration for dispensing. Recirculation serves to further dissolve powder not dissolved upon first contact with the water and to increase the strength of the solution. Upon time out of the recirculation pump, a dispensing pump operates to deliver the chemical concentrated liquid to the system being treated and at the rate desired. 
         [0014]    Once a low level of solution is detected in the reservoir, the dispensing pump stops and a fill solenoid valve is opened to refill the reservoir. This valve closes upon sensing of a full level in the reservoir, and recirculation can begin again. Water soluble packages of chemical powder are replenished as needed. 
         [0015]    The invention may dispense slug doses of chemical solution intermittently with dormant periods of several days. There may be chemical solution or residue remaining in the reservoir after a dispensing cycle is completed, in which case the reservoir is refilled and the dispensing pump is run again, emptying the reservoir of the fresh water into the system being treated for flushing the reservoir to prevent and reduce fumes emanating from the residue. Rinsing can be repeated several times. 
         [0016]    Suitable controls are provided to run the apparatus and provide appropriate warnings for malfunctions of the fill, dispense or recirculation cycles. 
         [0017]    Accordingly, in one embodiment of the invention, chemical powder in water dissolvable packages is exposed to a water spray from a reservoir with the diluted and dissolved chemical falling back into the reservoir. Spray from the reservoir of the solution is recirculated for a controlled time to fully dissolve the powder into the solution which is then introduced into a system for treatment. Thus the chemical powder is delivered to the dissolver in packaged form without human contact, recirculating spray sufficiently dissolves the chemical into a solution of increasing and sufficient strength for use in a system, powder packages can be recharged into the dissolver without breaking or making any pump or line connections or stopping a dispensing cycle, and off gassing of any residue is reduced or eliminated. Alternately, the recirculating spray is directed onto chemical in solid form, packaged or not, with resulting dissolving and increasing solution strength. 
         [0018]    These and other objectives and advantages will be readily appreciated from the following written description and from the drawings in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a graphic depiction of a flow chart according to the invention; 
           [0020]      FIG. 2  is an isometric view of the invention taken of its front side; 
           [0021]      FIG. 3  is a top plan view of the embodiment of  FIG. 2 ; 
           [0022]      FIG. 4  is an isometric view of the backside of the invention of  FIGS. 1-3  with portions cutaway for clarity and the charcoal filter removed; 
           [0023]      FIG. 5  is a back elevational view of the invention of  FIGS. 2-4  with portions broken away for clarity; 
           [0024]      FIG. 6  is a cross-sectional view of the invention of  FIGS. 2-5  taken alone lines  6 - 6  of  FIG. 3 ; 
           [0025]    and 
           [0026]      FIG. 6A  is a diagrammatic illustration of the two component screens of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    Turning now to the figures, there is shown in  FIG. 1  flow chart for a powder dissolving dispenser  10  according to the invention. Dispenser  10  includes, without limitation, a reservoir  12  for containing, first, a diluent such as fresh water, then the solution while it is being mixed and dispensed. A solenoid actuated water inlet valve  14  can be opened to first fill the reservoir  12 . A float  16   a  operated backup mechanical shutoff valve  16  is provided in the event the inlet valve  14  fails in its open position and would otherwise allow reservoir  12  to overflow. 
         [0028]    Pump  18  is disposed in pump housing  36  and is operably connected between the solution in reservoir  12  and a spray nozzle  20  to recirculate the solution for mixing. For dispensing, a dispensing pump  22  is also disposed in housing  36  and is operably connected to the solution to pump the mixed solution to a dispensing outlet  24 . 
         [0029]    A receptacle  26  in housing  26   a  extends upwardly from housing or cover  28  of reservoir  12  for receiving a plurality of water dissolvable packages  100  of chemical in powder or solid form therein, or in individual discrete solid forms without package coverings. 
         [0030]    Packages  100  in one embodiment are made of any suitable water dissolvable material. When dissolved, chemical, such as chemical powder therein is exposed. Receptacle  26  is of any suitable size, preferably large enough to hold one hundred packages  100  of about one pound weight each. Receptacle  26  is preferably covered with a removable top  30  which can be removed to allow more packages filled into receptacle  26  without removing any packages  100  therein and without stopping the dispensing operation, or requiring any pump or water or solution line disconnects. Packages  100  or solid forms can be of any size and shape, that shown in the FIGS. being exemplary only. 
         [0031]    A screen  32  is operably located preferably at and across the bottom  34  of receptacle  26 . Packages  100 , and any powder exposed from a dissolved package  100 , are disposed on and above screen  32 . Nozzle  20  is oriented to spray upwardly onto and through screen  32  and thus onto packages  100  in receptacle  26  and onto exposed powder above the screen  32 . First water, then recirculating solution, is sprayed through nozzle  20  onto and through screen  32 . Exposed powder from one or more packages  100  is engaged by the water, then solution, which at least further dissolves portions of the powder and, carrying undissolved powder, then falls back into reservoir  12  from where pump  18  recirculates the solution to nozzle  20 , further spraying the solution onto and through screen  32  to further dissolve packages  100  and powder therein, carrying the powder into the solution in reservoir  12 . This recirculation of solution serves to further mix and dissolve the powder into solution. After predetermined time consistent with the duration of recirculation to sufficiently dissolve the powder into a desired strength of solution, the dispensing pump  22  is operated to discharge the solution in reservoir  12  through dispenser outlet  24  and to a system to be treated with the solution. 
         [0032]    Screen  32  (see  FIG. 6A ) is preferably comprised of two screening components, a first metalized support screen  32   a  having a relatively open mesh of 2 to 4 wires per inch, for example, and a second screen or fabric  32   b  having a more closed mesh, such as 40 to 80 wires per inch, and preferably a 60 mesh. This second screen or fabric  32   b  may be comprised of woven stainless steel wires supported by the first screen underneath. Water or solution from nozzle  20  is sprayed onto and passes through screen  32 , with the first screen element  32   a  of more open mesh supporting the second screen element  32   b  of more closed mesh, such that the chemical is supported on screen  32  but sufficiently exposed to the spray from nozzle  20  for dissolving and passing through screen  32  back into the reservoir for increasing the solution strength therein. 
         [0033]    The mesh size of the second, more closed mesh screen component  32   b  is selected to optimize the passage of water but is small enough to block passage of significantly undissolved powder granules. 
         [0034]    Preferably there are provided two conductive probe pairs  40 ,  42 . Pair  40  is positioned to detect a low or empty solution level. Pair  42  is adjustable for detecting high or full solution level. Suitable volume or level sensors can be used, however, one useful system of useful probe pairs is further described in pending U.S. patent application Ser. No. 13/164,878 filed Jun. 21, 2011 entitled “SYSTEM AND METHOD FOR PRODUCT LEVEL MONITORING IN A CHEMICAL AND DISPENSING SYSTEM” hereby incorporated in its entirety by this reference as if fully set forth herein. 
         [0035]    An electronic controller  44  of any suitable type is operably connected and programmed to operate the system and sequence of operations as described herein. 
         [0036]    Housing  28  also operates to contain potential fumes produced by the mixed solution or residue in reservoir  12 . A charcoal filter  46  is preferably placed over vent  48  from housing  28  to collect and capture such fumes. 
       OPERATION 
       [0037]    The mixing/dispense cycle in one embodiment begins with the reservoir  12  full of fresh water and the chemical holder  26  full of the chemical to be dispensed. In one embodiment, up to 25 gallons of water at 50 to 90 degrees Fahrenheit is in reservoir  12 , with 50 one pound packages 100 of powder, such as granular biocide product, in receptacle  26 . As stated, other size packages can be used, as well as solid chemicals such as, for example, up to 100 pound solid inhibitor material or other weights thereof. 
         [0038]    The start of the mixing/dispense cycle is triggered either by an external signal or the controller  44  which includes a timer so dispenser  10  mixes then feeds the chemical solution at predetermined times. Up to 25 gallons of solution gets fed to the system to be treated per cycle. This solution will be from 0.5 to 10% concentrate at 50 to 90 degrees Fahrenheit. 
         [0039]    The cycle starts by running the recirculation pump  18  for a programmed time, such as for  120  minutes, for example, even if powder above the screen has already been exhausted. Other recirculation times or periods may be appropriate for different chemicals. This pump draws solution from the filled reservoir and discharges it through the spray nozzle  20 . The spray strikes the screen  32  covering the bottom of the chemical holder  26 . After the solution strikes the screen and the bottom of the chemical, the solution flows back into the reservoir. Other run times and volumes can be selected, depending on the chemical, the form, the packages and the solution concentration desired. 
         [0040]    When the mixing time has expired, the recirculation pump  18  stops and the dispensing pump  22  starts. Up to 25 gallons of solution at 50 to 90 degrees Fahrenheit, in this embodiment, is dispensed to a system to be treated through dispenser outlet  24 . 
         [0041]    The dispense pump  22  draws solution from the reservoir  12  and feeds it through outlet  24  into the system being treated. 
         [0042]    When the “low level” probe detects that the reservoir is empty, the dispense pump  22  stops and the fill solenoid valve  14  is opened to refill the reservoir. Water fills to a level up to about 25 gallons at 50 to 90 degrees Fahrenheit. 
         [0043]    When the “full level” probe  42  detects that the reservoir  12  is full, the fill solenoid valve  14  closes. If valve  14  fails to close, backup shutoff valve  16  operates to stop water flow into reservoir  12 . 
         [0044]    There is typically some chemical residue in the reservoir  12  at this time. This solution can produce fumes. After the reservoir is refilled, the dispense pump  22  can be run again to flush and empty the reservoir into the system being treated. This rinsing cycle may need to be repeated. The reservoir is then refilled with about 25 gallons of water supply temperature. Sometimes the water used to dissolve the chemical is very cold. Warmer water, such as at 50 to 90 degrees Fahrenheit, aids the dissolving of the chemicals used in this device. The reservoir is finally filled with water at the end of the dispense cycle to give the water time to warm to within a preferred temperature range. 
         [0045]    The typical use of this dispenser  10  in one embodiment is to dispense solution intermittently as scheduled, up to a total 25 gallons of solution at 0.05 to 50% strength at 50 to 90 degrees Fahrenheit. Typically a dispense operation may occur, for example, intermittently over one day and preferably every few days. 
         [0046]    It will be appreciated that the size of dispenser  10  can be varied to fit particular applications. For example, the dispenser  10  may be about four feet or so in overall height, with powder container  26  about 15 inches tall and 10 inches in inside diameter, and housing  26   a  about 27 inches tall, reservoir  12  about two feet tall and reservoir  12  about two feet square or slightly rectangular. Size variations are within the scope of the invention. 
         [0047]    Indeed, even if mixing or dispensing is stopped as a safety protocol for chemical loading, it will be appreciated that no water or pump connects need be broken or modified to refill the reservoir, in order to accommodate further chemical loading. 
         [0048]    It will be appreciated that it is not necessary to stop mixing or dispensing in order to add more chemical to receptacle  26 , however, that may be preferred. It is appreciated that it is not necessary to stop dispensing in order to add more chemical to receptacle  26 . Nor is it necessary to break or make any fluid connection or lines for introducing fresh chemical to receptacle  26  during dispensing. Also, it will be appreciated that a variety of treatment chemicals can be so dissolved into solution at different concentrations or strength and sufficiently mixed and dissolved into solution as desired. Thus, recirculation duration, water volume, powder volumes and dispensing timing, as well as the sizes, pump output and other parameters can all be varied to achieve a desired result, and all without handling of chemical powder and without handing of solution. Spills and undesirable human contact are eliminated, and a variety of chemical solutions, processes and treatment steps are available.