Abstract:
A diaphragm operated regulator valve usable, e.g., for maintaining a preset gas pressure in a potable storage container, provides particularly effective at gas flow regulation as well as pressure regulation. The use of the word “fluid” as used herein can encompass both liquids and gasses. The valve includes a gas-balanced piston-tower diaphragm assembly that is freely supported, sealed, and operatively connected to a pressure-biasing adjustment. The diaphragm assembly permits axial movement relationships between valving channels or pathways, a valving-seal, and volume changes that take place in a low-pressure chamber. The valve 1) converts axial movement of the diaphragm into smooth transitional flow rates by varying the cross sectional areas of ingress and egress from an open valve position to a closed valve position and 2) has the ability to preset maximum flow rates.

Description:
CROSS REFERENCE TO A RELATED APPLICATION 
   This application claims the benefit of the filing date of the earlier U.S. Provisional Patent App. Ser. No. 60/165,893, filed Nov. 12, 1999 an titled High to Low Gas Flow Regulator. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a regulator valve for maintaining a designated gas pressure at an output thereof, and more particularly to a regulator valve that maintains a preset gas pressure and a set maximum flow rate in a device such as a transportable container for potable liquids. 
   3. Discussion of the Related Art 
   Diaphragm operated regulator valves have been utilized to regulate the flow of compressed gas applied to a gas layer on top of liquids in a storage container and to other low pressure applications. The gas is normally a non-flammable gas, such as carbon dioxide and/or nitrogen. One such regulator valve is disclosed in U.S. Pat. No. 5,238,021, dated Aug. 24, 1993. In this valve, pressure flow is regulated via a diaphragm actuator. The diaphragm actuator is 1) relatively large, 2) very costly to manufacture, and 3) unsuitable in some applications of portable storage container operations. In addition, because regulator valves of this general type are no more than a poppet valve with a control spring, they cannot be changed to different flow rates without being re-manufactured. They also move open abruptly from a fully losed position to a fully-open position and, therefore, cannot transition smoothly from a closed position to an open position and cannot achieve a flow rate therethrough that is proportional to the amount of valve opening. 
   OBJECTS AND SUMMARY OF THE INVENTION 
   In accordance with the first aspect of the invention, a diaphragm operated regulator valve for maintaining a preset gas pressure in a potable storage container is provided with a relatively small diameter diaphragm and provides particularly effective at gas flow regulation as well as pressure regulation. The use of the word “fluid” as used herein can encompass both liquids and gasses. 
   The regulator valve is usable, e.g., as a potable fluid regulator valve rated at low fluid pressures. The valve includes a gas-balanced piston-tower diaphragm assembly that is freely supported, sealed, and operatively connected to a pressure-biasing adjustment. The diaphragm assembly permits axial movement relationships between valving channels or pathways, a valving-seal, and volume changes that take place in a low-pressure chamber. The valve 1) converts axial movement of the diaphragm into smooth transitional flow rates by varying the cross sectional areas of ingress and egress from an open valve position to a closed valve position and 2) has the ability to preset maximum flow rates. 
   The axial movement and sealing of valving channels exposed to fluid pressure occurs generally as disclosed in, U.S. Pat. No. 5,645,192 and U.S. Pat. No. 6,109,485, both of which are incorporated by reference in their entirety. This axial movement is the most important parameter in determining the sensitivity or responsiveness of the regulator valve to pressure changes. The valving channels or pathways are configured to cooperate with the associated valve seat so as to provide a smooth transition of gas flow between open and closed positions of the valve. 
   The regulator valve is very small in size (typically about 1 in. by 2 in. in diameter) and can provide regulated outlet-pressures as low as 1 psi at inlet-pressures above 2000 psi. By making use of threaded housings, fewer parts are required, and sub-assemblies can be used to improve automation of assembly and cost effectiveness. 
   Other features and advantages of the invention will be apparent from following drawings and graphs. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout, and in which: 
       FIG. 1  schematically illustrates a typical dispenser in which a regulator valve constructed in accordance with the present invention may be used; 
       FIG. 2  is a sectional side elevation view illustrating the gas regulator valve of  FIG. 1  as a complete assembly; 
       FIG. 3  is a sectional side elevation view illustrating one of the three units that make up the regulator valve; 
       FIG. 4  is a sectional side elevation view illustrating another of the three units that make up the regulator valve; 
       FIG. 5  is a sectional side elevation view illustrating still another of the three units that make up the regulating valve, 
       FIG. 6  is a partially exploded sectional side elevation view of the three units that make up the regulating valve; 
       FIGS. 7 and 7A  are a collection of sectional side elevation views of a portion of the regulator valve in its fully-closed position; 
       FIGS. 8 and 8A  are sectional side elevation views of a portion of the regulator valve its half-open position; 
       FIGS. 9 and 9A  are a collection of sectional side elevation views of a portion of the regulator valve in its full-open position; 
       FIG. 10  is an exploded side elevation view of the regulator valve; and 
       FIGS. 11 and 12  are a pair of graphs comparing operation of a regulator valve constructed in accordance with the invention to that of a prior art regulator valve 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to the drawings for a better understanding of the invention, and more particularly to  FIG. 1 , a dispensing storage container for liquids is shown generally at  1  and stores a potable liquid under a pressurized gas blanket or layer contained therein. A gas suitable for dispensing the liquid from the container may be carbon dioxide or some other non-flammable gas such as nitrogen. The gas is supplied by a source  3  that may, for instance, comprise a commercially available CO 2  cartridge. The pressure in the container  1  is controlled by a pressure regulator valve shown generally at  2 . The valve  2  is placed between the dispensing container  1  and the source of pressurized gas. The container  1  may comprise, e.g., a keg configured to dispense a beverage. It should be understood that the same valve  2  and other valves constructed in accordance with the present invention can be used in a variety of other applications including the dispensing of medicinal products, the dispensing of non-potable liquids, and any other application requiring the dispensing of a liquid or gas at a designated rate and/or a designated pressure. 
   Referring to  FIG. 2 , the valve  2  is formed from first, second, and third main units that are attached to one another to form a completed assembly in which a high pressure chamber  15  and a balance control chamber  33  are disposed at opposite ends of the valve  2  with a low pressure chamber  22  formed therebetween. The high pressure chamber  15  is connected to the high pressure source  3  via a hose or line connected to a threaded inlet  13 , and the low pressure chamber  22  is connected to dispensing container  1  either by direct communication or an intervening line or hose. All or nearly all valve components preferably are made of a plastic or another engineered polymer such as Polysulfone®. 
   Referring to  FIG. 3 , the first unit of the valve  2  includes a first housing  5  and a sub-assembly  9 ,  10  screwed into threads  18  formed on the inner diameter of a bore formed in a generally central portion of the housing  5 . The sub-assembly  9 ,  10  includes  1 ) a seal holder  10  threaded into a bore  34  in the housing  5  and  2 ) a seal  9 . The seal  9  has a plastic overlay and an elastomeric lip seal which is of the type disclosed in U.S. Pat. No. 5,645,192 and U.S. Pat. No. 6,109,485. The seal  9  functions as a valve seat to seal-off high pressure chamber  15  and high pressure source  3  from low pressure chamber  22  and container  1 . A replaceable flow-rate outlet orifice part  20  is screwed into low-pressure outlet threads formed in a radial bore  19  opening into the low pressure chamber  22 . The replaceable flow-rate outlet orifice part  20  can house any of a variety of different orifices  21  that set the rate of flow out of the low-pressure chamber  22  at a desired value. 
   Referring to  FIG. 4 , the second unit of the valve  2  includes a second housing  4  having a sub-assembly  9 ,  10  mounted in a stepped bore  32  formed in the housing  4 . The bore  32  has an upper portion  23  and a lower portion  37  separated by a flange  38 . The sub-assembly  9 ,  10  is faced with a keeper disk part  8  screwed into threads  23  in the inner end of the upper portion  23 , which forms the inner end of a balance control chamber  340  of the valve  2 . The sub-assembly  9 - 10  is identical to the corresponding sub-assembly of the first unit, hence permitting the use of interchangeable parts in the first two units. Another sub-assembly  6 - 26  of the second valve unit faces a sub-assemble  7 - 27  screwed into threads in the outer end  37  of the balance control chamber  33 . The sub-assembly  6 - 26  is formed from a cap seal  6  and an adjustment cap  26  threaded into the bottom end  37  of the bore  32 , and sub-assembly  7 - 27  is formed from a bias spring cap  7  and bias pressure spring  27  which biases the second unit towards the valve-open position. 
   Referring to  FIG. 5 , the third unit comprises a sub-assembly  11 - 17  extending through the low pressure chamber  22  and into the high pressure chamber  15  and the balance control chamber  40 . The sub-assembly  11 - 17  comprises a diaphragm  11  and a rod tower  17  that together, form a gas-balanced piston-tower valve part. The diaphragm  11  is bonded to rod tower  17  and has 1) an O-ring  30  portion formed or otherwise provided therein. The rod tower  17  has an internal passage  16  formed therethrough end  2  a plurality of external graduated pathways  14  that selectively permit a controlled flow of high pressure fluid into the low pressure chamber  22  from the high pressure chamber  15  as detailed below. The pathways  14  are formed from a plurality of peripherally-spaced grooves formed in the exterior surface of the rod tower. The depth of the upper end of each pathway  14  is tapered to provide smooth opening and flow rate control as detailed below. 
   The diaphragm  11  is clamped between the first and second housing  4  and  5  of the first and second units seal the low pressure chamber  22  from the balance control chamber  33 . More specifically, referring to  FIG. 6 , the orientation of the third unit between the second unit and the first unit allows the capture and confinement of  0 -ring portion  30  of diaphragm  11  between sealing grooves  31  and  29 , respectively, by screwing the female thread  24  on the first housing  5  to the male thread  25  on the second housing  4 . This orientation of the third unit requires the upper end of rod tower  17  to pierce through the seal  9  of the first unit into the high pressure  15  and the lower end of the rod tower  17  to pierce through the seal of  9  of the second unit into the balance control chamber  33 . 
   Operation 
   Referring again to  FIG. 2 , upon coupling the pressurized gas from source  3  to the high high pressure chamber  15 , gas flow will bifurcate at the upper end of rod tower  17  via the internal passage  16  and the external pathways  14 . The gas passing through passage  16  places the balance control chamber  33  in constant fluid communication with the high pressure chamber  15 , thereby negating any high-pressure thrust force differential at the ends of rod tower  17 . With little or no high-pressure thrust present on rod tower  17 , the bias force of the spring  27  will have connective control over the free axial movement of a gas-balanced piston-tower valve part  11 - 17  of the third unit against the volume change of low-pressure chamber  22 . The gas passing through the external pathways  14  will flow past the rod tower  17 , into low pressure chamber  22 , and into the container  1 . 
     FIGS. 7B-9C  collectively show the volume change of the exposed areas of the pathways  14  from open to mid to close. Detail view  9 B shows the valving-seat cross section of seal  9  at sealing-lip  12  and one quarter of whole valving pathway  14  of rod tower  17  when the valve  2  is in its rest or full open position. As gas migrates past sealing lip  12 , through pathways  14 , and into low-pressure chamber  22 , gas pressure in low pressure chamber  22  rises against confinement and forces diaphragm  11  to impart downward axial movement onto rod tower  17 . This axial movement will begin to close off gas-flow from the source  3  by moving the rod tower  17  downwardly to a position in which only the upper tapered ends of the pathways  14  extend past the sealing lip  12 . Detail view  8 B shows the mid point of this closure, and detail view  7 B shows full gas cut-off which occurs when the sealing lip  12  seals against the rod tower  17  above the pathways  14 . The reduced gas flow rate by movement of the rod tower  17  and consequent reduction of pathway inlet area achieves balance of the preset pressure in container  1  and cuts off gas-flow from the pressurized source  3 . 
   The rate of gas flow into the low pressure chamber  22  is controlled by the shape of the pathways  14 , and numerous rates of flow can therefore be defined with a gradual and progressive widening and deepening of this shape along the length of the rod tower as the rod tower  17  seals to lip  12  from full open to close. The gas flow rate variation with rod tower movement is very smooth and sensitive as compared to a standard pop open/pop-close valve. 
   The graphs of  FIGS. 11 and 12  show the relationship of gas-flow of the illustrated embodiment of the invention curve  50  in. ( FIG. 11 ) as compared to a standard regulator employing a poppet valve curve  52  in. (FIG.  12 ). The operating curves are plotted using cross sectional square area (in 2 ) of exposed gas pathway found at a given axial stroke of valve element movement in (thousands of an inch) as the valve opens and closes. The curve  50  of  FIG. 11 , illustrating operation of the embodiment of the invention described above, is smooth and gradual, showing that flow rates vary gradually with stroke. The curve  52  of  FIG. 12 , illustrating operation of a standard poppet valve seat, is very sharp because the valve is either fully open or fully closed. The data plotted by these cures is reproduced by the following tables: 
   
     
       
             
           
             
             
           
             
             
           
         
             
               TABLE 1 
             
           
           
             
                 
             
             
               FLOW CHARACTERISTICS OF REGULATOR 
             
             
               WITH INVENTIVE VALVE 
             
           
        
         
             
               Rod tower stroke distance (in) 
               Pathway cross sectional flow area (in 2 ) 
             
             
                 
             
           
        
         
             
               0.14 
               0.000188 
             
             
               0.13 
               0.000188 
             
             
               0.12 
               0.000188 
             
             
               0.11 
               0.000188 
             
             
               0.1 
               0.000188 
             
             
               0.09 
               0.000188 
             
             
               0.08 
               0.000169 
             
             
               0.07 
               0.000134 
             
             
               0.06 
               0.000115 
             
             
               0.05 
               0.000096 
             
             
               0.04 
               0.000063 
             
             
               0.03 
               0.0000321 
             
             
               0.02 
               0.0000104 
             
             
               0.01 
               0.0000054 
             
             
               0 
               0 
             
             
                 
             
           
        
       
     
   
   
     
       
             
           
             
             
           
             
             
           
         
             
               TABLE 2 
             
           
           
             
                 
             
             
               FLOW CHARACTERISTICS OF REGULATOR 
             
             
               WITH POPPET VALVE 
             
           
        
         
             
               Rod tower stroke distance (in) 
               Pathway cross sectional flow area (in 2 ) 
             
             
                 
             
           
        
         
             
               0.14 
               0.000188 
             
             
               0.12 
               0.000188 
             
             
               0.11 
               0.000188 
             
             
               0.1 
               0.000188 
             
             
               0.09 
               0.000188 
             
             
               0.08 
               0.000188 
             
             
               0.07 
               0.000188 
             
             
               0.06 
               0.000188 
             
             
               0.05 
               0.000188 
             
             
               0.04 
               0.000188 
             
             
               0.03 
               0.000188 
             
             
               0.02 
               0 
             
             
               0.01 
               0 
             
             
               0 
               0 
             
             
                 
             
           
        
       
     
   
   While a preferred embodiment of the present invention has been illustrated in detail, it is apparent that modifications and adaptations of the preferred embodiment will occur to those skilled in the art, and it is to be expressly understood that such modifications and adaptions of the preferred embodiment will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention as set forth in the following claims.