Patent Publication Number: US-6701953-B2

Title: Chemical mixing and metering apparatus

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates generally to an apparatus for mixing two components together. More particularly, the present disclosure relates to a fertilizer mixing and metering apparatus for adding a chemical fertilizer into a water supply line of an irrigation system. 
     2. Background to Related Art 
     A variety of different types of systems for mixing chemicals, including fertilizers, pesticides, herbicides, lime, etc., into irrigation supply lines are known. These systems include apparatus for adding liquid and solid chemicals into an irrigation supply line. Typically, liquid injection systems include a pump for injecting a chemical into the irrigation supply line, and solid chemical systems include a solid chemical container through which at least a portion of the irrigation fluid is directed. These systems are generally limited as to the type of chemical, i.e., liquid or solid, that they are able to mix with irrigation fluid. Moreover, such systems can be overly complex and not easily incorporated into existing irrigation systems. 
     Accordingly, a need exists for an improved chemical mixing apparatus which can be easily incorporated into existing irrigation systems and can be used with both liquid and solid chemicals. 
     SUMMARY 
     In accordance with the present invention, a chemical mixing and metering apparatus is provided which can be easily incorporated into existing irrigation lines. The apparatus includes a venturi which is positioned along an irrigation supply line. The venturi is connected to a chemical supply container by a chemical conduit and by a bypass conduit. A valve is positioned in the bypass conduit to regulate the flow of irrigation fluid from the irrigation supply line into the chemical supply container. A check valve or vent is provided in the container to prevent formation of a vacuum. 
     The presently disclosed chemical mixing and metering apparatus is operable in two modes of operation. Firstly, the apparatus may be operated as a vacuum system by closing the valve in the bypass conduit. Secondly, the system may be operated in a force feed/vacuum mode by opening the valve in the bypass conduit. Moreover, the apparatus may be used to inject solid and/or liquid chemicals into an irrigation system. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiment of the presently disclosed chemical mixing and metering apparatus are described herein with reference to the drawings, wherein: 
     FIG. 1 is a side elevational partial cross-sectional view of the presently disclosed chemical mixing and metering apparatus; 
     FIG. 2 is a cross-sectional view of the venturi of the presently disclosed mixing and metering apparatus shown in FIG. 1; 
     FIG. 3 is a cross-sectional, partial cutaway view of the venturi of the presently disclosed chemical mixing and metering apparatus incorporated into an existing irrigation line with adaptors attached thereto; 
     FIG. 4 is a top perspective, partial cutaway view of a removable reservoir or chemical holder assembly for use with the presently disclosed chemical mixing and metering apparatus shown in FIG. 1; and 
     FIG. 5 is a top perspective, partial cutaway view of an alternate embodiment of the removable reservoir or chemical holder assembly shown in FIG.  4 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Preferred embodiments of the presently disclosed chemical mixing and metering apparatus will now be described in detail with reference to the figures in which like reference numerals designate identical or corresponding elements in each of the several views. 
     Referring to FIG. 1, the presently disclosed chemical mixing and metering apparatus, shown generally as  10 , includes a chemical supply container  12 , a venturi  14 , a bypass conduit  16 , a chemical conduit  18 , and an irrigation fluid conduit  21 . Chemical supply container  12  includes body  20  defining a reservoir  22 . A cover  24  is removably secured to body  20  by screw threads (not shown). Alternately, cover  24  can be removably secured to body  20  using other known fastening techniques including screws, elastic bands, friction, etc. Cover  20  includes three openings  30 ,  32  and  34 . Opening  30  is dimensioned to receive and support the upper end of standpipe  36 . Standpipe  36  extends from a top portion of reservoir  22  towards the base of reservoir  22  and includes a bottom end having a filter or screen  38  secured thereto. An adaptor (not shown) is secured about opening  30  and is configured to releasably engage one end of chemical conduit  18 . Opening  32  includes a closeable vent such as a stopcock or the like. Alternately, vent opening  32  may include a check valve such as a spring-based ball check valve which allows flow into the container but not out of the container. Opening  34  includes an adaptor configured to engage one end of bypass conduit  16 . Bypass conduit  16  includes a valve  17  which can be opened to allow irrigation water to flow therethrough or closed to prevent irrigation water from flowing therethrough. 
     Referring to FIGS. 2 and 3, venturi  14  includes a converging and diverging conduit  39  including a converging section  44 , a central portion  42  and a diverging portion  40 . Venturi  14  includes a first bore  46  which opens into central portion  42  of converging and diverging conduit  39 . Bore  46  communicates with an adapter  48  having a bore  50  that communicates with chemical conduit  18 . Venturi  14  also includes a second bore  52  which opens into converging section  44 . Bore  52  is in fluid communication with an adapter  54  having a bore  56  in fluid communication with bypass conduit  16 . 
     Venturi  14  is adapted to be positioned or fitted in an irrigation supply line of an existing irrigation system. This can be accomplished by cutting a section of pipe from an irrigation supply line and securing venturi  14  in its place. Each end of venturi  14  may include screw threads  60  (FIG. 2) to facilitate securement to the irrigation line. Alternately, clamps  62  (FIG. 3) or other known fastening techniques may be used to secure venturi  14  in position in the irrigation supply line. 
     Chemical mixing and metering apparatus  10  may be operated in two different modes of operation. In each mode of operation, irrigation water is supplied from irrigation line  21  through venturi  14  in the direction indicated by arrow “P”. In a first mode of operation, valve  17  in bypass conduit  16  is opened to allow irrigation water to flow from venturi section  44 , in the direction indicated by arrow “A”, through opening  52 , into bypass conduit  16 , and into chemical supply container  12 . As the fluid flows through venturi  14  from convergent section  44  to divergent section  40 , through central portion  42 , the tapering constriction of the central portion of conduit  39  causes the velocity of the fluid flow to increase with a corresponding decrease in pressure in the area adjacent bore  46 . The combination of the decrease in pressure adjacent to bore  46  in conduit  39  and the increased pressure in supply container  12  caused by fluid flow from bypass conduit  16  causes chemicals in container  12  to flow upwardly through standpipe  36 , chemical conduit  18  and bore  46  into the central portion  42  of conduit  39  to mix with the irrigation fluid within irrigation line  21 . 
     In the first mode of operation, both liquid and solid chemicals can be distributed by mixing and metering apparatus  10 . Since, the chemical in container  12  is constantly being diluted as fluid enters container  12  through bypass line  16 , the concentration of the chemical in the fluid being distributed by the irrigation system in the first mode of operation will change with time. 
     In a second mode of operation, valve  17  in bypass line  16  is closed and vent  32  is opened Alternately, if a check valve with a preset opening pressure has been incorporated into system  10 , vent  32  need not be manually opened. As fluid flows through irrigation supply line  21  and venturi  14 , in the direction indicated by arrow “P”, chemical in container  12  is drawn from container  12  through chemical conduit  18  and bore  46  in venturi  14  and is mixed with the irrigation fluid. As discussed above, this occurs as a result of the decrease in fluid pressure adjacent bore  46  in venturi  14 . The flow rate of chemical through conduit  18  will change in response to changes in the irrigation fluid flow rate through venturi  14 . However, the concentration of the chemical in the irrigation fluid will be consistent over time if the irrigation fluid supply is maintained constant. 
     The components of chemical mixing and metering apparatus  10  can be formed of any material or materials meeting the requisite strength requirements including plastics and metals. Preferably, the components are formed of plastic such as polyvinyl chloride or Lucite®. It is also envisioned that venturi  14 , conduit  16  and conduit  18  can be formed, e.g., molded, of monolithic construction. Cover  24  can also be formed monolithically therewith. Alternately, each of the components may be individually constructed and secured to the other components using known fastening techniques including threads, welds, etc. 
     Referring to FIG. 4, chemicals may be added to container  12  using a removable reservoir or chemical holder assembly  100  which is preferably supported on cover  24 . Removable reservoir assembly  100  includes a cylindrical reservoir  102  and a cap  104 . Alternately, it is envisioned that reservoir  102  may have other configurations, e.g., rectangular, oval, square, etc. Reservoir  102  has an open top end. Cap  104  is removably secured to the open top end of reservoir  102  in a known manner, e.g., screw threads, friction fit, etc., to seal the reservoir. The outer surface of reservoir  102  or, alternately, cap  104  includes threads  106  for securing reservoir assembly  100  to cover  24 . Cap  104  preferably includes engagement structure  108 , e.g., allan wrench bore, phillips head bore, slotted bore, etc., formed therein to facilitate attachment of cap  104  to reservoir  102  and/or attachment of reservoir assembly  100  to cover  24 . 
     Reservoir  102  may be formed form a permeable material which allows a liquid chemical to diffuse therethrough at a controlled rate when it is placed within supply container  12 . Alternately, reservoir  102  may include one or more holes which allow chemical to escape from reservoir  102  into irrigation fluid located within supply container  112 . Preferably, reservoir  102  includes gradations indicating the amount of chemical located within reservoir  102 . Although illustrated as identifying the number of tablespoons of chemical in reservoir  102 , other units of measure may be used, e.g., ounces etc. 
     FIG. 5 illustrates another preferred embodiment of the removable reservoir or chemical holder assembly, shown generally as  200 . In assembly  200 , reservoir  102  has been replaced by a solid chemical  202 , solid chemical  202  is secured to a cap  204  which is adapted to be secured to cover  24  of container  12  in a manner similar to that disclosed above with respect to reservoir assembly  100 . 
     It will be understood that various modifications may be made to the embodiments disclosed herein. For example, although the apparatus was described for use with fertilizer systems, it is envisioned that apparatus may be suitable for other uses, e.g., mixing soap or detergents with water. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.