Patent Publication Number: US-2005115607-A1

Title: Liquid supply cutoff valve and liquid supply cutoff device incorporating the same

Description:
BACKGROUND OF THE INVENTION  
      This application claims priority to Japanese Patent Application No. 2003-399597 filed on Nov. 28, 2003, the contents of which is hereby incorporated by reference.  
      The present invention relates to a valve device which is installed in the middle of a liquid line for supplying beer to a beer server from a beer tank with pressure, and is quickly shut off when beer in the tank if fully consumed.  
      Commercial beer servers push beer out of a beer tank with pressurized carbon dioxide gas to supply beer from the beer tank. When beer still remains in the beer tank, the carbon dioxide gas pushes a surface of beer down, thereby supplies beer outwardly.  
      No problems are presented if beer still remains in the beer tank. When the tank is running out of beer, a mixture of froth and carbon dioxide gas are outwardly discharged in a burst. One who pours beer in a jug may sense the amount of beer close to emptiness and quickly closes a nozzle of the beer tank. Since beer is pressurized with at least one atmospheric pressure, it is difficult to avoid a burst of froth from the nozzle.  
      Intending to overcome the above-mentioned drawbacks, the inventors of present invention have previously disclosed a liquid supply cutoff valve in Japanese Laid Open Patent No. 2001-240194, the contents of which is hereby incorporated by reference.  
      Accordingly, there is a need for a liquid supply cutoff valve that quickly shuts the liquid line of beer from the beer tank with the pressure of carbon dioxide gas at the moment the beer tank is running out of beer. Furthermore, there is a need for a liquid supply cutoff device that provides ease of use by switching at least two beer tanks.  
     SUMMARY  
      A liquid supply cutoff valve of the present invention is arranged in a liquid passage line that is pressurized by a gas, and includes a primary liquid line, a secondary liquid line, a valve chest between the primary liquid line and the secondary liquid line, a spherical valve plug arranged in the valve chest, the spherical valve plug being lower in specific gravity than a liquid in the liquid line, and a valve seat arranged at the lower end opening of the secondary liquid line in the valve chest. The spherical valve plug is seated on the valve seat when the spherical valve plug is upward shifted, and an inside opening of the primary liquid line in the valve chest is at a level higher than the valve seat. While the liquid normally flows, the spherical valve plug is maintained at the position thereof by the liquid forming an eddy. The valve plug rotates at the position thereof when the liquid rises from the inlet port of the valve chest from the primary liquid line. The cutoff valve merely forms part of the liquid line. When the liquid becomes smaller in quantity, the liquid surface in the valve chest goes down. The valve plug also drops with the gravity thereof, and is drawn to the valve seat by a negative pressure of the secondary liquid line. The pressure of the gas pushes the spherical valve plug onto the valve seat. The cutoff valve thus functions as a cutoff valve with the spherical valve plug seated on the valve seat. In accordance with the present invention, the valve seat is incorporated to cause the spherical valve plug to seat on the valve seat when the spherical valve plug is lifted up to the lower end opening of the secondary liquid line. When the liquid level goes down to the lower end opening of the secondary liquid line within the valve chest, the spherical valve plug is shifted to the side of the valve seat while still having buoyancy, and is quickly seated onto the valve seat. Before the valve chest is filled with the pressure gas, the spherical valve plug is thus seated onto the valve seat, thereby reliably preventing the gas from being discharged through the secondary liquid line.  
      Preferably, the liquid supply cutoff valve includes a reset unit for pushing the spherical valve plug into the valve chest when the spherical valve plug is seated on the valve seat. The reset unit resets the spherical valve plug, which has been pressed against the valve seat with the gas pressure, to an open valve state. The liquid supply cutoff valve preferably includes a gas relief valve that is arranged at a level higher than the inside opening of the primary liquid line of the valve chest. To start supplying the liquid, the gas relief valve may be opened to discharge the gas that has filled the valve chest. The supplying of the liquid is commenced with the valve chest fully filled with the liquid. The negative pressure at the time of discharging the gas quickly pushes the spherical valve plug from the seating position thereof to the valve open position thereof.  
      The liquid cutoff device of present invention includes a plurality of liquid cutoff valves. The liquid cutoff valves are successively set to be ready for use one by one.  
      Other objects, features and advantages of the present invention will be apparent to those skilled in the art upon reading and understanding the following detailed description, the accompanying drawings and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention may be understood with reference to the following drawings. In the drawings, like reference numerals designate corresponding parts throughout the several views. Also, the components in the drawings are not necessarily to scale.  
       FIG. 1  is a piping diagram of a beer server system incorporating a liquid supply cutoff valve according to the present invention;  
       FIG. 2  is a longitudinal section of the liquid supply cutoff valve of the present invention in a liquid supply operation;  
       FIG. 3  is a longitudinal section of the liquid supply cutoff valve of  FIG. 2  in the liquid cutoff state thereof;  
       FIG. 4  is a longitudinal section of the liquid supply cutoff valve of  FIG. 3  with no beer remaining in a beer tank; and  
       FIG. 5  is a longitudinal section of the liquid supply cutoff valve of  FIG. 4  with a reset unit operated. 
    
    
     DETAILED DESCRIPTION  
      A first embodiment of the present invention is now discussed with reference to the drawings.  FIG. 1  is a piping diagram of an entire beer server system incorporating a liquid supply cutoff valve according to the present invention. As shown, the beer server system includes beer tanks T 1  and T 2 , a carbon dioxide gas cylinder  2  for applying pressure inside of the beer tanks T 1  and T 2 , a known beer server  3  having a cooling mechanism, and a nozzle  4  for pouring out beer. Also included are liquid supply cutoff valves  5  according to the present invention.  
      The liquid supply cutoff valves  5  are arranged in parallel as a liquid supply cutoff device such that one liquid supply cutoff valve  5  is ready for use after the other. Accordingly, when the first tank T 1  runs out of beer, beer is supplied from the second tank T 2 . The liquid supply cutoff valves  5  are present in the same quantity as the beer tanks T 1  and T 2  and are arranged downstream of the beer tanks T 1  and T 2 .  
      The carbon dioxide gas cylinder  2  is connected to the beer tanks T 1  and T 2 . A tank switching valve  6  causes one of the liquid supply cutoff valves  5  to be alternatively connected to the beer tanks T 1  and T 2 . A gas supply switching valve  7  applies gas pressure to a selected one of the beer tanks T 1  and T 2 .  
      The liquid supply cutoff valves  5  are respectively arranged for the beer tanks T 1  and T 2 , thereby forming the respective supply lines. The supply lines are thus exclusively selected, permitting a total amount of beer to be supplied in succession, for example, in a large restaurant. Since the number of the beer tanks T 1  and T 2  equals the number of liquid supply cutoff valves  5 , a reinstallation operation of the liquid supply cutoff valve  5  is not needed. Serving beer is smoothly performed.  
      The first embodiment of the present invention is only exemplary. Alternatively, a pair of liquid supply cutoff valves  5  and beer tanks may be used. The number of pairs of liquid supply cutoff valves  5  and beer tanks may be three or more so that the pairs may be alternately connected for use.  
       FIGS. 2 through 4  illustrate the internal structure of the liquid supply cutoff valve  5 , which is the essence of the present invention. As shown, the liquid supply cutoff valve  5  includes a housing  10 , an o-ring  11 , a spherical valve plug  12  which is lower in specific gravity than a liquid such as beer, a primary liquid line  13  of the valve, and a valve chest  15 . A valve seat (at the o-ring  11 ) is formed at a lower end opening of the secondary liquid line  14  within the valve chest  15  and is aligned to receive the spherical valve plug  12  when the spherical valve plug  12  is lifted upward. A reset rod  16  is urged at a position as shown by a spring  17 . When the spherical valve plug  12  is seated onto the o-ring  11  of the valve seat, the reset rod  16  is used to push the spherical valve plug  12  inwardly into the valve chest  15  to revert back to a normal liquid supply state.  
      The housing  10  and the spherical valve plug  12  may be made of any appropriate materials. For bulk production, the housing  10  and the spherical valve plug  12  are preferably made of a synthetic resin using a molding technique. It is a structural requirement that the valve seat (and o-ring  11 ) is lower in level (or relative elevation) than an inside opening of the primary liquid line  13  in the valve chest  15 . In such an arrangement, the liquid forms an eddy within the valve chest  15 . The secondary liquid line  14  must be larger in cross section (or diameter) than an inlet port  18  to restrict the current speed of the liquid to control the turbulent flow of the liquid.  
      A gas relief valve  19 , arranged at a level higher than the top end of the inlet port  18  of the primary liquid line  13 , discharges the gas, which fills the valve chest  15 , at the initial step of the liquid supply (i.e., during reset operation). After the gas relief valve  19  is opened to discharge gas during the reset operation and then closed, the supplying of the liquid is commenced with no gas remaining. During the reset step, the operation of the gas relief valve  19  allows the valve chest  15  to be fully filled with the liquid. In conjunction with the reset rod  16 , the gas relief valve  19  sets the spherical valve plug  12  to a position appropriate for liquid supplying.  
      The operation of the liquid supply cutoff valve  5  will now be discussed.  FIG. 2  shows the liquid supply cutoff valve  5  in a state in which the nozzle  4  is opened to allow beer to be pressurized by a carbon dioxide gas. Beer is introduced through the inlet port  18  into the valve chest  15  as shown by the arrows in  FIG. 2 , and forms a large eddy while running into the secondary liquid line  14  through the valve seat (and corresponding o-ring  11 ). Beer flows into the beer server  3  of  FIG. 1 . The spherical valve plug  12  being lower in specific gravity than the liquid attempts to float with buoyancy within the valve chest  15 , but is captured within the eddy. The spherical valve plug  12  is relatively stabilized at the position as shown in  FIG. 2  while being rotated.  
      When the supply of beer is suspended with the nozzle  4  closed, the liquid supply cutoff valve  5  takes a state shown in  FIG. 3 . The nozzle  4  functions as a final liquid supply suspension valve. Since the liquid supply cutoff valve  5  is located in the middle of the beer supply line, the beer is captured within the valve chest  15 . The spherical valve plug  12  being lower in specific gravity than the liquid is lifted to the top level within the valve chest  15 . Since the liquid supply cutoff valve  5  remains stable until the nozzle  4  is again opened, the spherical valve plug  12  keeps the position thereof as shown.  
      When the supply of beer resumes with the nozzle  4  opened, the liquid within the valve chest  15  forms a liquid supply line, and the spherical valve plug  12  is involved in the liquid supply line as shown in  FIG. 2 . If the inlet port  18  is lower in level than the valve seat (and corresponding o-ring  11 ), it becomes difficult to stabilize the spherical valve plug  12  at a position sufficient high in level, and the spherical valve plug  12  is expected to be drawn to the seating position on the o-ring  11  of the valve seat, thereby hinder (or completely blocking) the flow of liquid. The inlet port  18  must be higher in level than the valve seat  11 .  
      When the beer tank T 1  runs out of beer in the state shown in  FIG. 2 , the liquid in the valve chest  15  is pushed into the secondary liquid line  14  while forming a turbulent flow. As the liquid level drops, the spherical valve plug  12  also drops in position. Since the carbon dioxide gas still pressurizes the liquid, the spherical valve plug  12  is pressed against the o-ring  11  of the valve seat, thereby functioning as a cutoff valve. Since the application of the carbon dioxide gas is still continuous, the spherical valve plug  12  remains seated on the o-ring  11  of the valve seat.  
      If the empty beer tank T 1  is switched to a full beer tank T 2 , the gas relief valve  19  is opened. The gas relief valve  19  evacuates the gas from the valve chest  15 . The reset rod  16  is pushed in a direction represented by an arrow after the valve chest  15  is filled with the liquid as shown in  FIG. 5 . The spherical valve plug  12  comes off the valve seat  11  against the pressure of the carbon dioxide gas, thereby permitting the liquid to flow. When the liquid flow is stabilized, the state shown in  FIG. 2  is maintained.  
      The reset rod  16  is used to revert the spherical valve plug  12  back to the normal position in this preferred embodiment of the present invention. Alternatively, a pressure higher than the pressure of the carbon dioxide gas may be applied from downstream. Furthermore, a cam mechanism may be employed to push the reset rod  16 .  
      Although the present invention is shown and described with respect to certain embodiments, it is obvious that equivalents and modifications will occur to those skilled in the art upon reading and understanding the specification and the claims. The present invention includes all such equivalents and modifications and is limited only by the scope of the claims. For example, the present invention has been discussed with respect to a beer server. However, the present invention may be used for other liquids, such as, for example, carbonated drinks, juices and the like.