Abstract:
An apparatus for selective eductive dispensing of multiple chemical fluids from separate fluid containers includes a motive fluid inlet; an eductor in fluid communication with said motive fluid inlet; a selector switch defining at least one inlet and an outlet therein, said inlet and outlet in fluid communication with one another and said outlet in fluid communication with said eductor and wherein said selector switch inlet is in selective fluid communication with said fluid containers depending on the position of the selector switch; and a valve located between said motive fluid inlet and said eductor, said valve selectively opened and closed by movement of said selector switch.

Description:
TECHNICAL FIELD OF THE INVENTION 
   The present invention relates generally to eductive flow control systems and, more particularly, to a selection and flow control mechanism for an eductive dispensing system. 
   BACKGROUND OF THE INVENTION 
   Eductive dispensing systems designed to dispense multiple chemicals from a common outlet are generally known in the art. These systems generally utilize a centralized control box that is connected to a supply of eductive fluid, which is usually water, a supply of at least two chemicals from which the system can select, and an outlet, for example, a hose connected to a spray wand or nozzle, to dispense the desired mixture. These systems require mechanisms to (1) turn the flow of the eductive fluid on and off, which controls the operation of the entire system and (2) select the particular chemical to be dispensed with the eductive fluid. Prior art systems utilize two separate mechanisms to accomplish these tasks. In addition, the prior art systems generally utilize distinct chemical paths, with a separate eductor for each chemical path, for each chemical connected to the system. This design renders the eductor units in accessible for removal and cleaning or replacement. 
   U.S. Pat. No. 6,655,401 describes a multiple chemical eductive dispensing system that utilizes a separate selection control and eductive fluid inlet valve. The selection control includes separate eductors, also known as venturis, for each chemical path. This reference does refer to the possibility of turning the flow of all fluid off via the selector switch of the system, but does not describe how this may be done. 
   The prior art systems also lack a means for preventing the potential contamination of the individual chemical storage containers with the water/chemical mixture when flow of the mixture is shut off at the spray nozzle. When the flow of water/chemical mixture is shut of at the spray nozzle, pressure in the portion of the system below the eductor rises. If the pressure in this system reaches a level greater than the chemical inlet pressure at the eductor, then it is possible for the water/chemical mixture to overcome the inlet pressure and flow back into the chemical supply line. This contamination can result in overly diluted, and, therefore, ineffective, chemical being dispensed from the system. 
   The present invention is directed to overcoming one or more of the problems set forth above. 
   SUMMARY OF THE INVENTION 
   An aspect of the present invention is to provide a control mechanism for a multi-chemical eductive dispensing system capable of controlling both the flow of eductive fluid and selection of a desired chemical in a single selector means. 
   Another aspect of the invention is to provide a control mechanism for a multi-chemical eductive dispensing system that provides ready access to a single eductor unit for ease of maintenance and/or replacement. 
   Yet another aspect of the invention is to provide a control mechanism for a multi-chemical eductive dispensing system that prevents back flow of the eductive fluid/chemical mixture into the chemical supply system. 
   In accordance with the above aspects of the invention, there is provided an apparatus for selective eductive dispensing of multiple chemical fluids from separate fluid containers including a motive fluid inlet; an eductor in fluid communication with said motive fluid inlet; a selector switch defining at least one inlet and an outlet therein, said inlet and outlet in fluid communication with one another and said outlet in fluid communication with said eductor and wherein said selector switch inlet is in selective fluid communication with said fluid containers depending on the position of the selector switch; and a valve located between said motive fluid inlet and said eductor, said valve selectively opened and closed by movement of said selector switch. 
   In accordance with another aspect of the invention, there is provided an apparatus for selective eductive dispensing of multiple chemical fluids from separate fluid containers that includes a motive fluid inlet; an eductor in fluid communication with said motive fluid inlet; a selector switch defining at least one inlet and an outlet therein, said inlet and outlet in fluid communication with one another and said outlet in fluid communication with said eductor, said inlet in selective fluid communication with said fluid containers; and a pressure sensitive valve located between said eductor and said outlet in said selector switch, said pressure sensitive valve disrupting fluid communication between said eductor and said selector switch outlet when the pressure on the eductor side of the pressure sensitive valve rises above that on the selector switch side of said valve. 
   In accordance with yet another aspect of the invention, there is provided an apparatus for selective eductive dispensing of multiple chemical fluids from separate fluid containers including a motive fluid inlet; a single eductor in fluid communication with said motive fluid inlet; an outlet, wherein said single eductor is located proximate said outlet; a selector switch defining at least one inlet and an outlet therein, said inlet and outlet in fluid communication with one another and said outlet in fluid communication with said single eductor and said inlet in selective fluid communication with said fluid containers; and wherein flow of each of said multiple chemical fluids passes through said single eductor regardless of which chemical is selected and said single eductor is removable from said apparatus through said outlet. 
   These aspects are merely illustrative of the various aspects associated with the present invention and should not be deemed as limiting in any manner. These and other aspects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the referenced drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference is now made to the drawings which illustrate the best known mode of carrying out the invention and wherein the same reference numerals indicate the same or similar parts throughout the several views. 
       FIG. 1  is a partial view of a multi-chemical dispensing system according to an embodiment of the present invention with a portion of the system cover removed to show the components of the system. 
       FIG. 2  is a section view of a multi-chemical dispensing system showing the internal features of the system. 
       FIG. 3  is partial section view of a multi-chemical dispensing system from the front of the system. 
       FIG. 4  is a perspective view of the rear surfaces of a selector switch for use with a multi-chemical dispensing system. 
   

   DETAILED DESCRIPTION 
   In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. For example, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention. 
     FIGS. 1-4  illustrate a preferred embodiment of a control mechanism for a multi-chemical eductive dispensing system. The mechanism is contained within a housing  10  that protects the mechanism and provides a commercially preferable visual appearance. A motive fluid inlet  12  is provided for connection to a supply line  14 . The inlet is provided with a standard hose fitting  16 . 
   The system is also connected with a plurality of chemical fluid containers  18 . The containers  18  are connected to the system by supply lines  20 . The system is provided with multiple chemical inlets in the form of barbs  22 . The number of different chemicals that can be used with the system at one time is limited only by the number of chemical inlet barbs  22  provided in a particular embodiment. However, not all of the barbs  22  need to be utilized at all times. 
   The system permits selection from among one of the connected chemical fluid containers  18  by means of a selector switch  24 . In the illustrated embodiment, the selector switch is rotary switch with a knob  26  extending from the housing  10 . The switch is contained within a sleeve  28 . The rotary switch is  24  intended to fit snugly within the sleeve  28  while still being able to rotate within the sleeve. The rotary switch  24  contains an open passage  30  running generally along the axis of the rotary switch  24 . The passage  30  extends towards the interior end of the rotary switch  24 . In the preferred embodiment, the passage  30  is annular and surrounds a central body. At the interior end of the rotary switch  24 , the passage  30  narrows into an outlet  32 . A number of inlet openings  34  that fluidly connect the exterior of the rotary switch  24  with the passage  30  are arranged along the sides of the rotary switch  24 . 
   A number of outlet openings  36  are arranged around the sleeve  28 . The number of outlet openings  36  corresponds to the number of barbs  22  in the system. Each outlet opening  36  is fluidly connected with one barb  22 . The connection between the outlet openings  36  and the barbs  22  can be accomplished with molded manifolds that are integral with the housing  10  or tubing or by direct connection of the barbs with the outlet openings, among other possibilities. Those of skill in the art will recognize that multiple means can be utilized for this connection. The precise nature of this connection is not essential to the invention. 
   The inlet openings  34  of the rotary switch generally correspond to the outlet openings of the sleeve. In the preferred embodiment, a particular inlet opening  34  can be aligned with a particular outlet opening  36  in order to create a fluid passageway from the barb  22 , to the outlet  36 , through the inlet opening  34 , and into the passage  30  by rotating the knob  26 , and with it the rotary switch  24 . However, the relative position of the inlet openings  34  to one another is purposefully varied from the corresponding positioning of the sleeve outlet openings  36  to one another to ensure that only one inlet  34  and one outlet  36  are aligned at a time. In an alternate embodiment, only a single inlet opening  34  is provided in the rotary switch  24 , which is selectively rotated from outlet  36  to outlet  36 . In another embodiment, some number of inlets  34  greater than one but less than the number of outlets  36  is used. Those of skill in the art will recognize that a number of different combinations of rotary switch inlets  34  and sleeve outlets  36  can be utilized and will fall within the scope of the invention. While the preferred embodiment contemplates the dispensing of only one chemical at a time, it is within the scope of the invention to arrange the inlets  34  and outlets  36  so that two or more inlet/outlet pairs are aligned in order to dispense desired mixtures of multiple chemicals. 
   A seal  38  is positioned between the rotary switch  24  and the sleeve  26  to isolate the rotary switch inlets  34  from one another and to prevent fluid leaks. 
   To enable easier alignment of the desired inlets  34  and outlets  36 , the knob  26  is provided with spring-loaded detents  40 , which operate in a manner known to those of skill in the art. Each detent  40  is at location along the rotational path of the knob  26  corresponding to the alignment of a particular inlet  34  and outlet  36 . The detent  40  holds the knob  26  and rotary switch  24  in place with the desired inlet/outlet alignment. In the preferred embodiment, there is also a detent  40  that corresponds to a position of the rotary switch  24  at which no inlet  34  and outlet  36  are aligned. 
   The rotary switch  24  controls the flow of chemical to an eductor  42 , which is also referred to as a venturi or injector cartridge and is known in the art. The eductor  42  relies on a pressurized supply of motive fluid, which is water in most cases. The motive fluid enters the eductor  42  at the nozzle  44  forming a jet. This action creates a vacuum that draws chemical from the rotary switch outlet  32  into the eductor inlet  46 , where the chemical mixes and travels out of the eductor with the motive fluid. 
   The eductor  42  is supplied with motive fluid from the motive fluid inlet  12 . Manifolding or tubing connects the motive fluid inlet  12  with the eductor  42 . However, access of motive fluid to the eductor  42  is controlled by a shut off valve  48 . In the preferred embodiment, the shut off valve  48  utilizes a design disclosed in U.S. Pat. No. 6,607,174, which is commonly owned by the assignee of the present invention and is incorporated herein by reference. For convenience a brief description of the shut off valve  48  is provided herein 
   The shut-off valve  48  includes a body  50  having a threadedly connected cap  52 , an inlet  54  connected between the motive fluid inlet  12  and an inlet chamber  56 . The shut-off valve outlet  48  includes a valve seat  60  at its upper end and a valve element  62  which is shown in a closed position. In the embodiment shown, the valve element  62  includes a body  70  having a passage  71  and an annular web  72  having bleed holes  74  and an outer ring  75  and constitutes a diaphragm. The annular web outer ring  75  is clamped in place between the valve body  50 , a casing  72  and the valve cap  52 . 
   The valve element  62  is movable from a closed position, preventing flow through the valve seat  60 , to an open position, permitting flow through the valve seat  60 . Upward movement is resisted by a plunger  80  provided on the other side of the valve element  62 . The plunger  80  is enclosed in a casing  82 . The casing  82  includes a lower bell-shaped portion  84  having a flange  85 , which is held in place between the valve body  50  and the threadedly connected cap  52  and an upper tubular portion  86  having a diameter sufficiently large that the plunger  80  can slide within said upper portion  86  against the resistance of a spring  88  provided at the end of the casing tubular portion  86 . 
   In the valve closed position the valve element  62  is held against upward movement from water pressure in the inlet chamber  56  by water pressure in chamber  73 , by the location of the plunger  80  relative to a magnet  90  and by the spring  88 , which tends to hold the plunger  80  into the closed position. It will be appreciated that in the closed position, the area of the valve element upper surface in chamber  73  is greater than the area of the valve element lower surface in the inlet chamber  56  resulting in a net closing force due to water pressure on the valve element  62 . 
   The plunger  80  is magnetically attractive and can be moved vertically away from the valve element  62  by upward movement of a permanent magnet  90  carried in a retainer  81  by a carriage  92 . The carriage  92  includes a generally vertical member  94 , which is movable relative to the housing  10 , and an upper transverse member  96 , with which the magnet retainer  81  is integrally formed. The generally vertical member  94  is provided with a horizontal protrusion  98  adjacent its lower end. The horizontal protrusion  98  engages an interior surface of the knob  26 . Specifically, the protrusion rides along a cammed surface  100  provided on the interior surface of the knob  26  as the knob is rotated. While the protrusion  98 , and with it the carriage  92 , remains in one place, the cammed surface  100  presents higher or lower horizontal surface on which the protrusion  98  rests as the knob  26  is rotated. The changing height of the cammed surface  100  thereby raises and lowers the protrusion  98  and the carriage  92 . A spring  102  inserted between the housing  10  and the top surface of the carriage  92  biases the carriage  92  downward, thereby keeping the protrusion  98  in contact with the cammed surface. 
   Advantageously, the cammed surface  100  is arranged such that higher horizontal surfaces engage the protrusion  98 , thereby raising the carriage  92  and opening the shut off valve  48 , in those knob positions in which the rotary switch aligns an inlet  34  and an outlet  36 . This simultaneously permits the flow of motive fluid to the eductor  42  and opens a passage for the selected chemical fluid to flow to the eductor  42 . The lower horizontal surfaces of the cammed surface are arranged to engage the protrusion, thereby allowing the carriage to be forced downward by the spring  102  and closing the shut off valve  48 , in knob positions in which no inlet  34  and outlet  36  are aligned. In the preferred embodiment, there is another knob position in which the higher horizontal surfaces of the of the cammed surface  100  engage the protrusion  98  of the carriage  92 , thereby opening the shut off valve, while no inlet  34  and outlet  36  are aligned. This permits dispensing of motive fluid only as a rinse cycle. 
   Positioned between the rotary switch outlet  32  and the eductor inlet  46  is a pressure sensitive valve  104  which acts as a check valve. In a preferred embodiment, the pressure sensitive valve  104  is an umbrella valve having a sealing diaphragm  106  and a stem  108 . The stem  108  secures the valve to a perforated surface  110  between the rotary switch outlet  32  and the eductor inlet  46 . The perforated surface  110  may be integral with the sleeve  28  or may be a separate piece that is inserted into the sleeve  28 . 
   As illustrated in  FIGS. 2 and 3 , the eductor  42  is advantageously arranged in the outlet of the system at the bottom of the unit or another convenient access opening in the housing  10 . The eductor  42  is largely secured in place by hose fitting  112 . The eductor  42  may be quickly and easily removed by removing the hose fitting and pulling the eductor  42  out of the housing  10 . This arrangement allows easy removal and cleaning or replacement of the eductor  42 . In the preferred embodiment, the eductor  42  is an injector cartridge that can be removed in its entirety from the system. 
   Other objects, features and advantages of the present invention will be apparent to those skilled in the art. While preferred embodiments of the present invention have been illustrated and described, this has been by way of illustration and the invention should not be limited except as required by the scope of the appended claims and their equivalents.