Patent Publication Number: US-2006015994-A1

Title: Automatic dispenser

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      The present application claims benefit of U.S. Provisional Patent Application No. 60/591,061 filed Jul. 26, 2004 and entitled “Automatic Dispenser.” 
    
    
     FIELD OF INVENTION  
      The present invention relates to automatic liquid dispensers.  
     BACKGROUND OF THE INVENTION  
      Automatic liquid dispensers are used in many applications. One example is the dispensing of cleaning detergents into bathroom fixtures. Typically, a self-contained unit having a reservoir for storage of the liquid and having a battery operated pump is used. A common type of dispenser utilizes a piston-type pump to draw liquid from the reservoir into a conveying tube. There are some significant drawbacks related to these type of dispensers. Piston-type pumps are prone to losing prime which renders the pump inoperative. Also, the amount of liquid that is drawn from the reservoir will vary depending on the level of the liquid in the reservoir. When the reservoir is full there is less suction required to dispense the liquid, whereas when the reservoir is low it is more difficult to pull the liquid from the reservoir. What is needed is an inexpensive, automatic dispenser that dispenses a consistent quantity of liquid and is more reliable than the piston-type pumps.  
     SUMMARY OF THE INVENTION  
      The present invention meets the above-described need by providing an automatic dispenser that operates by pressure conveying the fluid out of the reservoir. The automatic dispenser includes an air pump in fluid communication with an inlet to the reservoir. A normally closed valve prevents the liquid from exiting the pressurized reservoir until a valve is opened.  
      The system operates as follows. On a predetermined, periodic basis, an air pump is activated. The air pump outlet is in fluid communication with the reservoir. The pump pressurizes the reservoir for a predetermined time period. Next, a valve is opened for a short period of time and liquid is conveyed from the reservoir into a conduit leading from the reservoir to the outlet of the automatic dispenser. From the outlet of the automatic dispenser to the fixture, the liquid may be conveyed by gravity. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which:  
       FIG. 1  is a perspective view of a typical application for the automatic dispenser of the present invention;  
       FIG. 2  is a plan view of the components of the present invention with the electrical wiring removed for clarity;  
       FIG. 3  is a schematic diagram of the automatic dispenser of the present invention; and;  
       FIG. 4  is an alternate embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION  
      Referring to  FIG. 1 , a typical application for the automatic dispenser  10  of the present invention is for dispensing liquid cleaning detergents through a conduit  11  to a fixture  13  such as a toilet or urinal. As shown, the liquid detergents are typically gravity fed from the outlet of the dispenser  10  to the fixture  13 . The dispenser  10  dispenses the liquids automatically on a predetermined, periodic basis as will be described in greater detail below.  
      Although the dispenser  10  of the present invention is being described in connection with dispensing liquid cleaning detergents to fixture  13 , the invention is not intended to be limited to that particular application. As will be described below, the dispenser  10  of the present invention also may have application for dispensing hostile fluids in other applications.  
      Turning to  FIGS. 2 and 3 , a reservoir  16  having a bottom wall  17 , side walls  18  and a top wall  19  stores a liquid  20  which may comprise a cleaning detergent. The reservoir  16  may be constructed of any suitable plastic or other material as will be evident to those of ordinary skill in the art. The reservoir  16  may be disposable or may be capable of being refilled for multiple uses. The reservoir  16  also has an inlet  22  and an outlet  25 .  
      An air pump  28  operated by an electric motor  31  is arranged such that the outlet  34  of the air pump  28  is placed in fluid communication with the inlet  22  to the reservoir  16  by means of conduit  37 . Although the invention is described in connection with an air pump other gases may also be suitable and for certain applications inert gases such as nitrogen may be required. The conduit  37  may comprise plastic tubing or other suitable materials as will be evident to those of ordinary skill in the art.  
      At the outlet  25  of the reservoir  16 , a conduit  40  is arranged such that the pick-up end  43  is disposed inside the reservoir  16 . As shown the pick-up end  43  may be extended toward the bottom wall  17 . For some liquids that tend to stratify, it is advantageous to extend the pick-up end  43  toward the bottom wall  17 .  
      The conduit  40  extends through the outlet  25  of the reservoir  16  to a pinch valve  50 . The pinch valve  50  is normally closed and operates by deforming the walls of the conduit  40  inward until the passageway through the conduit is closed off. As will be evident to those of ordinary skill in the art, the flexibility of the conduit  40  and the force of the valve  50  on the walls of the conduit  40  are adjusted such that the flow through the conduit  40  can be opened and closed repeatedly without causing leakage or mechanical failure of the conduit  40 . Although the pinch valve  50  is shown in the figure, any type of normally-closed, automatic valve suitable for use with a relatively small conduit may be substituted. The conduit  40  extends downstream of the valve  50  to the outlet  63 .  
      In operation, a controller  60  ( FIG. 3 ) activates the air pump  28  at a predetermined, periodic time period. The air pump  28  pressurizes the reservoir  16  for a predetermined period of time. Because the reservoir  16  is pressurized in this manner, the level or amount of liquid  20  contained in the reservoir  16  does not affect the quantity of fluid to be conveyed unless the reservoir is near empty and does not contain at least one charge of liquid. This feature is in contrast to the piston-type pumps which can lose prime and which convey different amounts of liquid depending on the amount or level of the liquid  20  contained in the reservoir  16 . Also, the viscosity of the liquid  20  is not critical with the dispenser  10  of the present invention. In contrast, for the piston-type pump, the viscosity of the liquid  20  is a significant factor.  
      After a predetermined period of time with the air pump  28  operating, the valve  50  is opened for a short period of time (typically less than one second) to allow a charge of liquid  20  to exit through conduit  40 . Conduit  40  leads to outlet  63  on the bottom side of the dispenser  10 .  
      Turning to  FIG. 3 , a power supply  66  provides power to the controller  60 . The power supply  66  may comprise batteries but other power supplies may also be suitable as will be evident to those of ordinary skill in the art. As described above, the controller  60  activates the air pump  28  on a periodic basis. The controller also activates the valve  50  at a predetermined time period after the activation of the pump  28 .  
      The present invention offer several advantages including the fact that there is no direct contact between the liquid  20  and any of the electromechanical components of the system. Accordingly, there is no issue with contamination of the pump or the valve and no need for seals or O-rings. This feature may be even more significant in applications where the liquid  20  comprises a hostile fluid.  
      Also, the pressure-conveying system of the present invention is not affected by small leaks in the line because the pump  28  is capable of operating at a rate sufficient to overcome any pressure loss due to small leaks.  
      Another advantage of the system is the ability of the system to mix liquids that are susceptible to stratifying. For example, biocides have a tendency to separate such that the active organisms become concentrated toward the bottom. Because of the pressurization of the reservoir  16  and the location of the pick-up end  43  toward the bottom wall  17 , a more homogeneous mixture of the liquid  20  is conveyed than would be possible with a piston-type pump.  
      In an alternate embodiment shown in  FIG. 4 , the pump  28  is eliminated from the system. In the alternate embodiment, the fluid is conveyed from the reservoir via gravity. Reservoir  100  is positioned an outlet  103  at the bottom such that liquid  106  can by conveyed by gravity into conduit  109 . The flow of liquid is controlled by a pinch valve  112 .  
      While the invention has been described in connection with certain embodiments, it is not intended to limit the scope of the invention to the particular forms set forth, but, on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.