Abstract:
An anti run-on device is provided for use in a refrigeration appliance, wherein the refrigeration appliance includes a water dispenser including a water reservoir, a water conduit extending downstream from the water reservoir to a water spout, and a user operable valve positioned in the water conduit upstream of the reservoir and the water spout. The anti run-on device comprises a constriction in the conduit between the valve and the water spout, a small hole in the conduit located either at or just downstream of the constriction, and a vacuum chamber in communication with the small hole. A Venturi or knife edge effect is created when water is flowing through the conduit to evacuate the vacuum chamber, so that when the valve is closed, water between the small hole and the water spout is drawn into the vacuum chamber, thereby precluding dripping from the water spout.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to water dispensers, and more particularly, to a water dispenser for use with a refrigeration apparatus and including an arrangement to prevent dripping or run-on of the water dispenser.  
           [0002]    Manufacturers of refrigerators have offered, as a feature of their product, a water dispenser mounted to the exterior of the refrigerator door. Such a water dispenser is usually combined with a water reservoir, remotely located within the refrigerated compartment, to provide ready access to chilled water without the need to open the refrigerator door. A conduit extends between the water reservoir and the water spout from which the water is directed into a vessel such as a drinking glass. A valve, typically operated by a lever arm pressed by a glass is used to control the dispensing of water.  
           [0003]    A common problem, associated with refrigerator dispenser mechanisms, is run-on. Run-on is dripping of water from the tube while it is not in use. There are several causes of run-on. The water reservoir expands when pressurized and contracts when de-pressurized. This causes water to run for a short time immediately after removing the glass. This effect is enhanced by compressible air bubbles trapped in the water reservoir. Dissolved air in the water can come out of solution at the low pressures in the reservoir. The added volume causes run-on. Water reservoirs sometimes freeze. The expanding ice displaces water causing dripping. All of these effects are caused by a volumetric displacement of water somewhere in the dispensing system after the water valve is turned off.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention provides an arrangement for preventing dripping from the water spout in a water dispenser for a refrigerator after the shut off valve has been closed. Immediately upon the shut off valve being closed, any water in the conduit from the point of the shut off valve to the water dispenser is withdrawn back into the conduit by a suction force, thereby preventing any dripping from the water spout. In an embodiment, a reservoir is provided which communicates with the conduit and which is maintained below atmospheric pressure during a flow of water through the conduit such that when the valve is closed, any water remaining in the conduit from the valve to the water spout is drawn into the reservoir area by a suction action and is held there until a further dispensing of water occurs.  
           [0005]    In an embodiment, the invention comprises the use of a rigid plastic tube which is surrounded by a vacuum chamber. A Venturi type vacuum device is built into the plastic tube so that when water passes through it, a vacuum is created in the surrounding chamber. When the water is turned off, water flows into the vacuum chamber due to the reduced pressure. This creates a volumetric buffer for any type of run-on that may occur. The vacuum chamber may be made of a rigid material if a small buffer is desired or an elastic material for a larger buffer volume. In the rigid design, a pressure lower than the vapor pressure of water is required to create the buffer. In the elastic design, the vacuum chamber material could have some degree of shape memory. When the water is flowing, the elastic vacuum chamber collapses due to the reduced pressure inside. When the water is turned off, it would expand, creating a larger buffer volume. There should be sufficient internal volume in the dispensing conduit, in the direction of flow, downstream of the vacuum chamber, to prevent external air from entering the vacuum chamber. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0006]    [0006]FIG. 1 is a front view of a refrigerator having a water dispenser incorporating the principles of the present invention.  
         [0007]    [0007]FIG. 2 is a side view of a water dispenser with which the present invention can be utilized, taken generally along the line II-II of FIG. 1.  
         [0008]    [0008]FIG. 3 is the same view as FIG. 2, but showing the water dispenser actuated by a drinking glass.  
         [0009]    [0009]FIG. 4 is a schematic illustration of an arrangement for locating the anti-run-on device of the present invention in a water flow line.  
         [0010]    [0010]FIG. 5 is a side sectional view of an embodiment of the present invention.  
         [0011]    [0011]FIG. 6 is a side sectional view of an embodiment of the invention.  
         [0012]    [0012]FIG. 7 is a sectional view taken generally along the line V-V of FIG. 4.  
         [0013]    [0013]FIG. 8 is a side sectional view of a further embodiment of the present invention.  
         [0014]    [0014]FIG. 9 is a side elevation view of an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0015]    The present invention relates to an anti run-on device for preventing dripping from a conduit after a liquid valve has been closed. While the invention finds particular utility in a refrigeration appliance where a water dispenser may be provided in the door of the appliance, the invention is not limited to such use and can be used in any liquid conduit positioned between a shut off valve and an open end of the conduit. However, to provide a specific example of the invention, the invention is disclosed as used in connection with a refrigeration appliance.  
         [0016]    Referring to FIG. 1, a refrigerator  20  is provided with a door  22  for gaining access to a below freezing compartment (not shown). Located centrally on the outer face of the door  22  is an outwardly opening housing  24  in which are mounted an ice dispenser  26  and a water dispenser  28 .  
         [0017]    As shown in FIG. 2, the water dispenser  28  has an actuator  30  which is pivotally attached to a back surface  32  of housing  24  by a pin  34 . An upper extension  36  of dispenser actuator  30  terminates in a pad  38 . A dispensing switch  40  is mounted with a push button type operator  42  in alignment with the pad  38  so that when the dispenser actuator  30  is rotated counter clockwise around the pin  34 , the pad  38  will actuate the operator  42 , as seen in FIG. 3. A torsion spring (not shown) associated with the pin  34  biases the actuator  30  to the position shown in FIG. 2. Thus, after the actuator  30  is rotated to the position shown in FIG. 3, it will subsequently return to the position shown in FIG. 2.  
         [0018]    Operation of the switch  40  completes an electrical circuit between a source of power and a solenoid operated valve  44  (FIG. 4) connected to a water supply. The solenoid valve  44  is also connected to a water reservoir  46  which is connected to a water spout  48  by an interconnecting tube or conduit  50 . Thus, when the valve  44  is opened, pressurizing reservoir  46 , water is caused to be delivered to the water spout  48 .  
         [0019]    A lower extension  52  of the actuator  30  terminates in a cradle shaped glass receiving portion  54 . As illustrated in FIG. 3, the glass receiving portion  54  is configured to allow a drinking glass to be conveniently pressed against the dispenser actuator  30  and dispense water from the water spout  48 , located above the glass receiving portion  54 , into the glass.  
         [0020]    In FIG. 4 there is schematically illustrated an improved water dispensing system incorporating the principles of the present invention. The water spout  48  is shown as being connected by the tube or conduit  50  to the water reservoir  46  and dispensing valve  44 , and also including the improvement of the provision of anti run-on device  60  being positioned in the conduit  50  between the water reservoir  46  and the water spout  48 .  
         [0021]    In FIG. 5 there is illustrated an embodiment of the anti run-on device  60  incorporating the principles of the present invention. In this embodiment, the conduit  50  is severed and a rigid tube  62  is slipped over the severed ends of the conduit  50  and is secured thereto by appropriate fastening means such as compression nuts  64 . The rigid tube  62  may be formed of any acceptable material, including appropriate plastic materials. A restrictor  66  is inserted into the rigid plastic tubing adjacent to an end of the conduit  50  which leads downwardly (in FIG. 5) to the water reservoir  46 . The restrictor  66  has a reduced diameter passage  68  therethrough and may include a funnel shaped lead in opening  70  to guide the water into the passage  68 . Immediately downstream of the end of the reduced diameter passage  68  the rigid tube  62  has a relatively small hole  72  formed therein. A vacuum chamber  74  formed by a vacuum chamber wall  76  surrounds the rigid plastic tube  62  and including the area including the hole  72 .  
         [0022]    As water flows from the water reservoir  46  to the water spout  48 , it flows in an upward direction, in the orientation of FIG. 5, through the conduit  50  and passes through the reduced diameter passage  68 . Because of the reduced diameter of the passage  68 , the speed of the water flow increases and therefore the pressure decreases. This produces a reduced pressure zone in the area at the hole  72 , (a Venturi effect) and thereby reduces the pressure in the vacuum chamber  74  causing any liquid in that chamber to be drawn out of the chamber and intermingled with the water stream proceeding to the water spout  48 . If the vacuum chamber wall  76  is formed of a rigid materials, then preferably the passage  68  of the restrictor  66  is sized, in combination with the flow rate through the conduit, to reduce the pressure in the vacuum chamber  74  below the vapor pressure of water, so as to cause all of the water collected in the vacuum chamber  74  to be drawn through the hole  72  and into the conduit  50  as water is dispensed through the water spout  48 . If the vacuum chamber wall  76  is formed of a flexible material, then the pressure in the vacuum chamber  74  only needs to be reduced to below atmospheric pressure, which will result in a collapsing of the wall  76  and a subsequent squeezing of the water out of the vacuum chamber.  
         [0023]    When the dispensing of water is terminated by release of the actuator  30 , water downstream of the restrictor  66 , that is, between the restrictor and the water spout  48 , is drawn by the reduced pressure in the vacuum chamber  74  through the hole  72  and into the vacuum chamber, thereby withdrawing an end of the remaining water column in the conduit  50  away from the water spout  48  and toward the anti run-on device  60 . The size of the vacuum chamber  74  is selected so that it will accommodate a sufficient volume of water at the conclusion of each dispensing operation to withdraw the end of the water column in the conduit  50  far enough away from the water spout  48  such that any expansion or volumetric displacement of the water in the dispensing system after the water valve has been turned off will be insufficient to cause the end of the water column in the conduit from moving all of the way to the water spout  48 . The size of the vacuum chamber  74  should also be selected so as to draw thereinto less than all of the water between the vacuum chamber and the water spout  48  so that air is not drawn into the vacuum chamber from the water spout opening.  
         [0024]    A second embodiment of the anti run-on device  60  is illustrated in FIGS. 6 and 7 in which a metal insert tube  80  is placed into the interior of the conduit  50 . The insert tube  80  may be formed of metal, such as brass, or an appropriate plastic. A restrictor  82  is provided in the insert tube  80  and includes a reduced diameter opening  84  through which the water flows from the water reservoir  46  to the water spout  48  (from left to right in FIG. 6). The restrictor  82  may be an opening  84  in a disk-shaped insert, such as a flat washer, and the opening  84  creates a “knife edge” effect, reducing the pressure in the area just downstream of the restrictor. A sloped or conical lead in zone is not necessary when using a knife edge restrictor, and such a construction can be used in any of the embodiments of the anti run-on device disclosed herein. The insert tube  80 , as well as the conduit  50 , are provided with a hole  86  just downstream of the restrictor  82 . Surrounding the insert tube  80  and conduit  50  in the area including the hole  86  is a vacuum chamber  88  formed by a vacuum chamber wall  90  (rigid or flexible as described above). The vacuum chamber wall includes a central portion  92  spaced away from the conduit  50  and end portions  94  spaced closely adjacent to the conduit  50  such that a water tight seal can be effected between the end portions  94  and the conduit  50  by appropriate means. If the conduit  50  and the vacuum chamber wall  90  are both formed of appropriate plastic materials, the end portions  94  can be sealed to the conduit  50  such as by hot staking. As in the previous embodiment, when water flows from the water reservoir  46  to the water spout  48 , it passes through the opening  84  of the restrictor  82 , thereby reducing pressure adjacent to the hole  86  and creating a low pressure area within the vacuum chamber  88 , withdrawing any collected water therefrom into the conduit  50  for dispensing through the water spout  48 . When the actuator  30  is released, thereby terminating water flow through the conduit  50 , the end of the water column in the conduit  50  is drawn back toward the anti run-on device  60  in that a volume of water is drawn into the vacuum chamber  88  due to the low pressure residing therein. The same volume considerations described in the previous embodiment pertain to this embodiment as well. Hence, the volume of the vacuum chamber  88  will be determined, in part, by the distance from the anti run-on device  60  to the water spout  48  and the diameter of the conduit  50 .  
         [0025]    In FIGS. 8 and 9 there is shown another embodiment of the anti run-on device  60 . In this embodiment, the device is preferably formed as a one piece, blow molded, construction and can be made of a plastic material such as medium density polyethylene.  
         [0026]    As seen in FIGS. 8 and 9, the anti run-on device  60  includes an inlet tube  100  for connection to the conduit  50  leading to the water reservoir  46 . There is also an outlet tube  102  for connection to the conduit  50  leading to the water spout  48 , or, the outlet tube  102  may comprise the water spout  48  itself. An internal diameter  104  of the inlet tube  100  is reduced to a much smaller internal diameter at a passage  106  downstream of the inlet tube  100  and the reduction in diameter can be provided by a cone shaped wall  108 . Alternatively, a knife edge restrictor could be used as described above to provide the constriction in the inlet tube  100 . In the reduced diameter passage  106  there is a hole  110  leading to a vacuum chamber  112  formed by vacuum chamber wall  114  (rigid or flexible as described above).  
         [0027]    Positioned between the outlet tube  102  and the reduced diameter passage  106  is a water chamber  116  through which the water flows from the water reservoir  46  to the water spout  48  which is particularly useful when the outlet tube  102  is the water spout  48 .  
         [0028]    As in the embodiments above, when water is being dispensed, the speed of the water flow is greatly increased in the reduced diameter passage  106 , thereby creating a low pressure in the area of the hole  110  and reducing the pressure within the vacuum chamber  112  so that all of the water contained therein is withdrawn through the hole  110  and dispensed along with the water flow which then passes through the water chamber  116  and the outlet tube  102  to the water spout  48 . When the actuator  30  is disengaged and water through the conduit stops flowing, the water between the hole  110  leading to the vacuum chamber  112  and the water spout  48  is sucked into the vacuum chamber  112  through the hole  110  and the end of the water column is drawn away from the water spout  48 . The water chamber  116  is provided in the event that the anti run-on device  60  is placed very close to the water spout  48 , such as when the outlet tube  102  is the water spout. As described above, it is not desired to draw air into the vacuum chamber  112  and therefore a sufficient volume of water must be present between the vacuum chamber hole  110  and the end of the water column near the water spout  48  when flow is terminated so that the entire water column is not drawn into the vacuum chamber  112 , thereby allowing air to also come into the vacuum chamber. Therefore, the water chamber  116  is dimensioned to provide a sufficient volume of water to be drawn into the vacuum chamber  112  after the flow of water is terminated so as to prevent any air from being drawn into the vacuum chamber  112 . Upon the next dispensing of water, any water still remaining in the water chamber  116 , as well as water drawn into the vacuum chamber  112 , will be dispensed out through the outlet tube  102  and to the water spout  48 .  
         [0029]    As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that the scope of the patent warranted hereon is intended to include all such modifications as reasonably and properly come within the scope of the disclosed contribution to the art.