Patent Publication Number: US-6216913-B1

Title: Self-contained pneumatic beverage dispensing system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of the filing date of U.S. Provisional Application Serial No. 60/030,628, filed Nov. 8, 1996, and is a Continuation-in-Part of U.S. patent application Ser. No. 08/965,711, filed Nov. 7, 1997, now U.S. Pat. No. 6,021,922. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to a beverage dispensing system. More particularly, the present invention relates to a self-contained, high pressure pneumatic beverage dispensing system especially adapted for use on commercial aircraft, railcars, ships, and the like, as well as for installation in golf carts and other such small vehicles. 
     BACKGROUND OF THE INVENTION 
     Conventionally, beverage dispensing systems require electrical or gasoline power. Therefore, these systems tend to be bulky and usually are unsuitable for portable applications. Typically, such conventional beverage dispensing systems comprise a high pressure carbonator tank plumbed to a carbon dioxide (CO 2 ) cylinder through a pressure regulator in which the pressure to be supplied to the carbonator tank is reduced to approximately 90 pounds per square inch (psi). A motorized pump plumbed to a fixed water tap system is used to pressurize the water supplied to the tank to approximately 200 psi. The high pressure water flows into the carbonator tank, overcoming the rising pressure of the CO 2  gas contained therein. As the carbonator tank fills with this high pressure water, a pocket of CO 2  gas that exists above the water is compressed, forcing the CO 2  gas to be absorbed into the water, thereby creating carbonated water. 
     In that the conventional beverage dispensing systems described above require a constant source of power to operate the pump motor, use of such systems is generally limited to fixed installations. Although portable beverage dispensing systems that do not require electrical or gasoline powered pumps have been developed, these systems have several disadvantages. One such system is disclosed in U.S. Pat. No. 5,411,179 (Oyler et al.) and U.S. Pat. No. 5,553,749 (Oyler et al.). Similar to the systems described in the present disclosure, the systems described in these patents use high pressure CO 2  gas supplied by a CO 2  tank to pressurize the water that is supplied to a carbonator tank. Unlike the systems described in the present disclosure, however, the systems described in these patent references use low pressure carbonator tanks which typically operate at pressures below 100 psi. 
     Despite providing for some degree of water carbonation (typically approximately 2.5%), known systems typically do not produce beverages having a commercially acceptable level of carbonation (generally between 3.0% to 4.0%). Experimentation has shown that the pressurized water often must be cooled to a low temperature prior to entering the carbonator tank of these systems to achieve fill absorption of CO 2  gas into the water. Moreover, the CO 2  gas that is absorbed into the carbonated water can quickly be diffused from the water when it is heated to a warmer temperature. Accordingly, when the carbonated water is post-mixed with relatively warm liquids, such as concentrated syrups, juices, and the like, the relatively small amount of carbonation of the water quickly can be lost. 
     It therefore can be appreciated that it would be desirable to have a self-contained beverage dispensing system that is portable and which produces beverages having a commercially acceptable level of stable carbonation. 
     SUMMARY OF THE INVENTION 
     Briefly described, the present invention relates to a self-contained, pneumatic beverage dispensing system. In one embodiment, the pneumatic beverage dispensing system comprises a carbonator tank for facilitating absorption of CO 2  gas in water to produce carbonated water, a source of CO 2  gas under high pressure, the source of CO 2  gas being in fluid communication with the carbonator tank so as to fill the carbonator tank with CO 2  gas, and a source of water under high pressure, the source of water being in fluid communication with the carbonator tank so as to fill the carbonator tank with water. The system normally further comprises at least two liquid containers for containing liquids to be dispensed by the dispensing system, one of the liquid containers being in fluid communication with the source of CO 2  gas, and a pneumatic pump system in fluid communication with the source of CO 2  gas and the other of the liquid containers. In operation, the pneumatic pump system receives high pressure CO 2  gas from the source of CO 2  gas and uses it to pressurize air that is supplied to the other of the liquid containers. Finally, the system further includes a beverage dispensing valve in fluid communication with the carbonator tank and the at least two liquid containers, the dispensing valve used to dispense carbonated water from the carbonator tank and the liquids contained in the at least two liquid containers. 
     The features and advantages of this invention will become apparent upon reading the following specification, when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. 
     FIG. 1 is a schematic view of a first embodiment of a self-contained pneumatic beverage dispensing system constructed in accordance with the present invention. 
     FIG. 2 is a cut-away side view of a high pressure carbonator tank used in the beverage dispensing system of FIG.  1 . 
     FIG. 3 is a cut-away side view of the carbonator tank of FIG. 2 with a pneumatic water level switch mounted thereto, this switch also shown in cut-away view to depict the activated or fill position of the switch. 
     FIG. 4 is a cut-away side view of the carbonator tank of FIGS. 2-3 showing the pneumatic water level switch in the inactivated or full position. 
     FIG. 5 is a side view of a cart-mounted version of the beverage dispensing system of FIG.  1 . 
     FIG. 6 is an end view of the cart-mounted version of the beverage dispensing system of FIG.  5 . 
     FIG. 7 is an exploded view of a liquid container shown in FIGS. 5-6. 
     FIG. 8 is an upper perspective view of a bottle coupler shown in FIG. 5, the coupler being depicted in the closed position. 
     FIG. 9 is a lower perspective view of the bottle coupler of FIG.  8 . 
     FIG. 10 is an upper perspective view of the bottle coupler of FIGS. 8-9, the coupler being depicted in the open position. 
     FIG. 11 is a detailed schematic view of a pneumatic pump system shown in FIG.  1 . 
     FIG. 12 is a schematic view of a second embodiment of a self-contained pneumatic beverage dispensing system constructed in accordance with the present invention. 
     FIG. 13 is a cut-away view of a water pump used in the beverage dispensing system of FIG.  12 . 
     FIG. 14 is a schematic view of a first alternative carbonator tank and filling system. 
     FIG. 15 is a schematic view of a second alternative carbonator tank and filling system. 
    
    
     DETAILED DESCRIPTION 
     Referring now in more detail to the drawings, in which like numerals indicate corresponding parts throughout the several views, FIGS. 1-12 illustrate various components of a first embodiment of a self-contained pneumatic beverage dispensing system  10  constructed in accordance with the present invention. 
     FIG. 1 is a schematic view of the first embodiment of the self-contained pneumatic beverage dispensing system  10 . The system  10  generally comprises a source  12  of CO 2  at high pressure, a source  14  of high pressure water, a high pressure carbonator tank  16 , and a beverage dispensing valve  18 . The source  12  of CO 2  typically comprises a conventional refillable gas storage tank  20  that is filled with pressurized CO 2  gas. As is discussed in more detail below, the pressurized CO 2  gas contained within the gas storage tank  20  is used for various purposes including carbonating water in the carbonator tank  16 , pressurizing water to be supplied to the carbonator tank, and pressurizing various drink syrups and juices. 
     The CO 2  gas exits the gas storage cylinder  20  through a gas shut-off valve  22 . When the gas shut-off valve  22  is open, CO 2  gas travels through a gas outlet  24  and is supplied to three separate gas pressure regulators  26 ,  28 , and  30 . The gas traveling through the first pressure regulator  26  is reduced in pressure to approximately 95 psi and then travels to a supply line  32 . The supply line  32  directs the CO 2  gas to a gas inlet check valve  34  of the high pressure carbonator tank  16  so that the carbonator tank can be filled with pressurized CO 2  gas. In addition, the gas is directed to a fourth pressure regulator  35 . The CO 2  gas that travels through the fourth gas pressure regulator  35  further is reduced in pressure to approximately 75 psi. After exiting the fourth gas pressure regulator  35 , the CO 2  gas flows into a supply line  36  which is connected to a carbonator tank water level switch  40 , the configuration and operation of which is described below. 
     The CO 2  gas that travels through the second gas pressure regulator  28  is reduced in pressure to approximately 45 psi. After passing through this regulator  28 , the gas enters supply line  42 . As indicated in FIG. 1, this supply line  42  branches into two branches  43  and  242  such that the 45 psi gas communicates with one or more containers  44 , and with a pneumatic pump system  45  that is used to pressurize one or more other containers  44 . The containers  44  are connected to supply lines  47  that, in turn, are connected to a cold plate  48  which cools the liquids that flow from the containers to an appropriate mixing or serving temperature. From the cold plate  48 , the liquids can be discharged through the beverage dispensing valve  18 . A detailed description of the pneumatic pump system  45  as well as the containers  44  is provided below. 
     The CO 2  gas supplied to the third gas pressure regulator  30  is lowered in pressure to approximately between 195 psi to 200 psi. After passing through the third gas pressure regulator  30 , the CO 2  gas is ported through a gas supply line  50  that supplies this gas to the high pressure water source  14 . In the first embodiment shown in FIGS. 1-12, the water source  14  comprises a high pressure water tank  52 . Although capable of alternative configurations, this water tank  52  typically is constructed of a strong metal such as stainless steel. Inside the water tank  52  is a flexible diaphragm  54  that separates the interior of the water tank into two separate chambers  56  and  58 . The first or water chamber  56  of the water tank is adapted to store water that will be supplied to the carbonator tank  16  for carbonization. The second or gas chamber  58  is adapted to receive high pressure gas that is used to pressurize the water contained in the water chamber  56 . The flexible diaphragm  54  completely isolates each chamber from the other such that no mixture of the water and CO 2  gas can occur. 
     Connected to the water chamber side of the water tank  52  is a water supply line  60 . Among other functions discussed below, the water supply line  60  is used to refill the water chamber  56  of the water tank  52 . To refill this chamber, a refill inlet check valve  62  connected to a branch of the water supply line  60  is connected to a source of water having positive head pressure which, depending upon personal preferences, can be a source of purified water or a standard tap water source. Positioned along the supply line  50  between the third gas pressure regulator  30  and the water tank  52  is a three-way vent valve  63 . The three-way vent valve  63  is manually operable to control the pressurization or depressurization of the gas chamber  58  of the water tank  52 . When switched to an open position, the three-way vent valve  63  directs high pressure CO 2  gas into the gas chamber  58  of the water tank  52  which urges the pliable diaphragm  54  against the volume of water contained in the water chamber  56  to increase the pressure of the water to a level within the range of approximately between 195 psi to 200 psi. When the operator wishes to refill the tank  52  with water, the three-way vent valve  63  is manually switched to a closed position in which the supply of high pressure CO 2  gas to the tank  52  is shut-off and the high pressure gas contained in the gas chamber  58  of the water tank is vented to the atmosphere to relieve the pressure therein. Preferably, this gas is first directed to a first vent line  65  which leads to a diffuser  67  which, as is known in the art, gradually diffuses the vented gas into the atmosphere to reduce noise. Once the pressure within the tank  52  is reduced, the operator can refill the tank with any water source capable of supplying water at a positive bead pressure. 
     In addition to providing for refilling of the water tank  52 , the water supply line  60  further is used to transport the pressurized water in two separate directions. In a first direction, the water is supplied to a water valve  64  that is positioned intermediate the water tank  52  and the carbonator tank  16 . Typically, the water valve  64  is pneumatically actuated to open or close to thereby permit or prevent the flow of water therethrough. In a preferred arrangement, the water valve  64  comprises a normally closed, gas actuated, high pressure bellows valve. Considered suitable for this use are HB Series bellows valves manufactured by Nupro. Coupled with a pneumatic signal line  66 , the water valve  64  and water level switch  40  are in fluid communication with one another. When supplied with a pneumatic pressure signal sent from the water level switch  40 , the water valve  64  opens, permitting high pressure water supplied by the water tank  52  to pass through the valve and into a carbonator tank supply line  68 . In use, the water is transported into the tank  16  through a water inlet check valve  70  that is mounted to the carbonator tank. 
     In addition to transporting high pressure water in the first direction to the water valve  64 , the water supply line  60  transports high pressure water in a second direction to a water pressure regulator  72 . This pressure regulator  72  reduces the pressure of the water supplied from the water tank to approximately 45 psi to 60 psi. From the water pressure regulator  72 , the water flows through a flat water supply line  74  and then through the cold plate  48  to be dispensed by the beverage dispensing valve  18  when activated by the operator. 
     FIG. 2 illustrates, in cut-away view, the carbonator tank  16  preferred for use in the embodiment shown in FIGS. 1-12. As depicted in the figure, the carbonator tank  16  comprises a generally cylindrical tank  76 . Mounted to the top of the cylindrical tank  76  are the gas inlet check valve  34  and the water inlet check valve  70  as well as a safety relief valve  78 , all of which are of conventional design. Further mounted to the top of the carbonator tank  16  is a carbonated water outlet  80  that is fluidly connected to a carbonated water supply line  82  (FIG.  1 ). Inside the carbonator tank  16  is a carbonated water supply tube  84  that extends from the bottom of the tank up to the carbonated water outlet  80  such that, when the beverage dispenser valve  18  is activated to produce carbonated water, the pressurized carbonated water from the bottom of the carbonator tank is forced through the supply tube  84 , out of the carbonated water outlet  80 , through the carbonated water supply line  82 , through the cold plate  48 , and finally out of the dispensing valve into a suitable beverage container C. 
     The carbonator tank  16  further comprises a mechanical water level indicator  86 . This indicator  86  includes a hollow float member  88  having a rod  90  extending upwardly from the top portion of the float member. Positioned on the top of the rod  90  is a magnetic member  92  normally in the form of a magnetic cylinder. When the carbonator tank  16  is empty, the float member  88  rests on the bottom of the carbonator tank. While the tank is situated in this empty configuration, part of the magnetic member  92  is positioned within the tank and part is positioned within an elongated hollow tube  94  that extends upwardly from the top of the carbonator tank. This hollow tube  94  permits travel of the rod  90  and magnetic member  92  in the upward direction, the purpose for which will be explained herein. Presently considered to be in accordance with the above description is the Model M-6 carbonator available from Jo-Bell. 
     As the carbonator tank  16  is filled with water, the buoyancy of the float member  88  causes it to float towards the top of the tank. To maintain the float member  88 , rod  90 , and magnetic member  92  in correct orientation, a mechanical stabilizer  96  is provided. As illustrated in the figure, the stabilizer  96  can comprise a retainer band  98  that is wrapped around the float member  88  and a slide member  100  which is disposed about the carbonated water supply tube  84  and to which the retainer band is fixedly attached. Configured in this manner, the float member  88  will continue to rise within the carbonator tank  16  as the water level within the tank increases. Similarly, the magnetic member  92  will rise within the elongated hollow tube  94  so that water level sensing means can detect when the tank  16  is full, so that water flow into the tank can be halted. 
     As described above, the water level within the tank  16  is monitored and controlled by a carbonator tank water level switch  40  that is mounted to the carbonator tank. FIGS. 3 and 4 illustrate the water level switch  40  and part of the carbonator tank in cut-away view. Preferably, the water level switch  40  comprises an outer housing  102  that is adapted to be positioned in close proximity to the hollow cylinder  94  of the carbonator tank  16 . Located within the housing  102  is a pneumatic three-way magnetic proximity switch  104  and a lever arm  106 . While the proximity switch  104  is fixed in position within the housing  102 , the lever arm  106  is free to pivot about a pivot point  108  such that the lever arm is pivotally mounted within the water level switch  40 . Mounted to the lever arm  106  are first and second magnets  110  and  112 . The first magnet  110  is mounted to the arm at a position in which it is adjacent the proximity switch  104  when the lever arm is vertically oriented as shown in FIG.  3 . 
     Being attracted to the proximity switch  104 , the first magnet  110  maintains the lever arm  106  in the vertical orientation when the tank  16  is not full. When the lever arm  106  is in this vertical orientation, positive contact is made with the proximity switch  104 , thereby activating the switch and causing it to send a pneumatic pressure signal to the water valve  64  to remain open so that the carbonator tank  16  can be filled. As the water level rises, however, the magnetic member  92  within the hollow tube  94  rises, eventually moving to a position in which it is adjacent the second magnet  112  mounted on the lever arm. Since the magnetic member  92  is constructed of a magnetic metal, such as magnetic stainless steel, the second magnet  112  of the lever arm  106  is attracted to the cylinder. In that the attractive forces between the second magnet  112  and the magnetic member  92  are greater than those between the first magnet  110  and the proximity switch  104 , the lever arm  106  pivots toward the magnetic member  92  as depicted in FIG.  4 . By pivoting in this direction, magnetic contact between the first magnet  110  and the proximity switch  104  is interrupted, thereby deactivating the proximity switch and shutting-off the supply of pressurized CO 2  gas to the water valve  64 , causing the normally closed valve to cut-off the flow of water to the carbonator tank  16 . 
     FIGS. 5 and 6 illustrate the beverage dispensing system  10  of FIG. 1 integrated with a cart  114  suitable for use on a passenger vehicle such as an airplane. As indicated in this figure, the cart  114  comprises an interior compartment  116  that houses the majority of the system components including the source  12  of CO 2  and the source  14  of high pressure water. Also stored in this compartment  116  is a plurality of the containers  44  identified in FIG.  1 . As indicated most clearly in FIG. 7, each of the containers  44  typically comprises a bottle  118  and a bottle coupler  120  which, when disposed in a cart as shown in FIGS. 5 and 6, can be stored within the compartment  116  in an inverted orientation. The bottle  118  normally is formed from a polymeric material and is provided with a mouth  122 , a shoulder  124 , and a neck  126 . 
     The bottle coupler  120  is shown in detail in FIGS. 8-10. As indicated in these figures, the bottle coupler  120  generally comprises an outer member  128  and an inner member  130  that is slidingly disposed within the outer member. The outer member  128  is substantially tubular in shape so as to be formed as an elongated, hollow cylinder having a first end  132  and a second end  134 . Formed at the first and second ends  132  and  134  of the outer member  128  are first and second collars  136  and  138 , respectively. As indicated in FIGS. 8 and 9, each of these collars  136 ,  138  are non-continuous in nature in that both are interrupted by a notch  140  and  142 , respectively. Pivotally connected to the outer member  128  at the notch  140  is a bottle release lever  144 . In the closed position of the lever  144  shown in FIG. 8, the lever extends from the first collar  136  of the outer member  128  and generally parallel along the length of the outer member. 
     Pivotally mounted to the bottle release lever  144  is a needle valve lever  146 . The needle valve lever  146  is provided with a cam surface  148  that, when the bottle release lever  144  is in the closed position, normally contacts a needle  150  of a needle valve (not shown) that is located within the inner member  130 . This needle  150  extends beyond the outer member  128  through a first opening  152  formed in the side of the outer member. As indicated in FIG. 9, the outer member  128  further includes a second opening  154  that extends from the second notch  142  along a portion of the length of the outer member. For reasons described below, this opening  154  comprises a first portion  156  adapted to receive the mouth  122  of a bottle  118 , and a second portion  158  adapted to receive the shoulder  124  of the bottle. 
     The inner member  130  normally is formed as an elongated, substantially solid cylinder having a first end  162  and a second end  164 . Positioned on its first end  162  is liquid outlet port  166 , a gas inlet port  168 , and a vent port  170 . The liquid outlet port  166  is in fluid communication with the bottle  118  mounted thereto through a liquid passage  172  that extends from the outlet port to the second end  164  of the inner member  124  at which point it forms a valve seat  174 . Formed within the liquid passage  172  is an internal reservoir  176  that is adapted to hold a predetermined amount of liquid as well as a valve closure member  178  such as a ball that is sized and configured to rest within the valve seat  174 . 
     The gas inlet port  168  similarly is in fluid communication with the bottle  118  through a gas passage  180  that extends from the inlet port to an external conduit  182  that, as shown in FIG. 5, is adapted to extend deep into the bottle  118  when the bottle is mounted to the bottle coupler  120 . The vent port  170  is in fluid communication with the needle valve located within the inner member  130  through a vent passage  184 . The needle valve, in turn, is selectively placeable in fluid communication with both the liquid passage  172  and the gas passage  180 . As indicated in FIG. 9, the second end  164  of the inner member  130  is countersunk so as to form an annular space  186  in which the mouth  122  of a bottle  118  can be disposed. Within this annular space  186  is a gasket  188  that is used to form an airtight seal between the bottle  118  and its coupler  120 . 
     As indicated in FIGS. 8 and 10, the bottle coupler  120  further comprises a link member  190  that is pivotally attached to the bottle release lever  144  at one end, and pivotally attached to the inner member  130  at its other end. In that the pivot point of the lever member  190  is outwardly displaced from the pivot point about which the bottle release lever  144  can pivot, manipulation of the bottle release lever effects linear displacement of the inner member within the outer member. When the lever  144  is in the closed position shown in FIG. 8, the inner member  130  extends downwardly into the first portion  156  of the second opening  154  of the outer member such that a bottle  118  disposed within the annular space  186  cannot be removed therefrom. As the bottle release lever  144  is lifted, however, the link member  190  is displaced so as to effect linear displacement of the inner member  130  along the interior  160  of the outer member  128 . FIG. 10 shows the bottle release lever  144  in the fully open position. Once in this position, the second end  164  of the inner member  130  is clear of the first portion  156  of the outer member second opening  154  such that a bottle  118  can be inserted into or removed from the coupler  120 . 
     To connect a full bottle  118  of liquid, for example soft drink syrup, to a selected bottle coupler  120 , the bottle coupler first is arranged so that it can be attached to the bottle in a manner in which the bottle is maintained in an upright position during connection. Where the beverage dispensing system  10  is integrated into a cart  114  as shown in FIGS. 5 and 6, this step comprises extending the bottle coupler  120  out from the cart interior compartment  116  and inverting the coupler. This extension and reorientation is possible due to the flexible, retractable tubes  192  with which each bottle coupler  120  is connected to the remainder of the system (FIG.  7 ). Assuming the selected bottle coupler  120  is not presently coupled to a bottle  118 , the bottle release lever  142  is moved to the fully open position depicted in FIG. 10 so that the inner member  130  is axially displaced within the outer member  128  towards its first end  132 . The mouth  122  and shoulder  124  of the bottle  118  then are positioned into the interior  160  of the outer member  128  by passing the bottle through the second opening  154  formed in the outer member. Once the mouth  122  and shoulder  124  of the bottle are disposed within the interior  160  of the outer member  128 , the bottle shoulder will be in abutment with an interior shoulder  194  formed at the second end  132  of the outer member. At this point, the bottle release lever  144  can be moved to the closed position shown in FIG. 8 to axially displace the inner member  130  toward the mouth  122  of the bottle  118  and, eventually, firmly urge the gasket  188  against the mouth of the bottle. If it is not already in the closed position, the needle valve lever  146  can be closed by orienting it in the position shown in FIG.  8 . When in this position, the valve needle  150  is in the fully depressed position which opens the gas passage  180  and closes the vent passage  184  such that gas cannot vent out from the bottle. CO 2  gas can then flow into the bottle  118  through the external conduit  182  to pressurize the liquid contained within the bottle such that the liquid will flow out from the bottle, along the liquid passage  172 , and out through the outlet port  166  when the particular fluid is needed. 
     If the operator wishes to change the bottle  118  (e.g. if it is empty), the operator first rotates the needle valve lever  146  outwardly. The lever&#39;s cam surface  148  is oriented such that, as the lever is rotated, the needle  150  is permitted to extend outwardly from the coupler  120  until, at a predetermined point, the needle valve located within the inner member  130  closes the gas passage  180  and opens the vent passage  184  to the bottle to permit the gas remaining within the bottle to vent to the atmosphere through the vent port  170 . At this point, the bottle  118  can be removed from the bottle coupler  120  by again moving the bottle release lever  144  to the fully open position illustrated in FIG.  10 . 
     FIG. 11 illustrates a detailed schematic view of the pneumatic pump system  45  shown in FIG.  1 . The pump system  45  generally comprises a gas side  196  and an air side  198 . The pneumatic pump system  45  further comprises a double acting pump  200  that extends through both the gas side  196  and the air side  198  of the system. The double acting pump  200  typically is arranged as an elongated cylinder having an outer tube  202  having a first end  204  and a second end  206 . Positioned intermediate the first and second ends  204  and  206  is a central dividing member  208  that airtightly separates the pump  200  into a first or air chamber  210  and a second or gas chamber  212 . Extending through the central dividing member  208  is a piston rod  214  having first and second ends  216  and  218 . Rigidly connected to each of these ends  216 ,  218  is a first piston head  220  and a second piston head  222 . Each of these piston heads  220 ,  222  is provided with at least one seal that prevents the passage of gas or air around its periphery during use. Disposed within the gas side  196  of the pump  200  are first and second proximity sensors  226  and  228  that, as is described below, send pneumatic signals to a master control valve  230  that controls operation of the pump. 
     The double acting pump  200  is provided with a plurality of pneumatic line connections schematically represented in FIG.  11 . With respect to the gas side  196 , the pump  200  is provided with first and second gas supply lines  232  and  234 . As shown in the figure, the first gas supply line  232  connects to the pump  200  adjacent the central dividing member  208 , and the second gas supply line  234  connects to the pump adjacent its second end  206 . These gas supply lines  232 ,  234  extend from the pump  200  to the master control valve  230 . Also connected to the pump  200  on the gas side  196  of the system  45  are first and second signal lines  236  and  238 . The first signal line  236  is in fluid communication with the first proximity sensor  226  and the second signal line  238  is in fluid communication with the second proximity sensor  228 . As with the gas supply lines  232 ,  234 , the first and second signal lines  236  and  238  similarly connect to the master control valve  230 . In addition to their connections to the signal lines  236 ,  238 , the proximity sensors  226 ,  228  further are in fluid communication with a sensor gas supply line  240 . This center gas supply line  240  is connected to a main gas supply line  242  that receives CO 2  gas at approximately 45 psi from the second pressure regulator  28 . The gas side  196  further includes a vent line  244  which extends from the master control valve  230  to the first vent line  65  (FIG.  1 ). As indicated in FIG. 1, this vent line  244  normally includes a check valve  246  that is placed between the pneumatic pump system  45  and the diffuser  67  such that high pressure gas venting from the water tank  52  cannot be transported directly to the pneumatic pump system  45 . 
     With respect to the air side  198  of the pneumatic pump system  45 , the double acting pump  200  includes an air supply line  248  that, as shown in FIG. 1, is connected to an air filter  250 . The air supply line  248  is connected to first and second air passage lines  250  and  252  that connect to the pump  200  at its first end  204  and adjacent the central dividing member  208 , respectively. The air side  198  of the pneumatic pump system  45  further includes an air output line  254  that, like the air supply line  248 , is connected to two air passage lines, namely a third air passage line  256  and a fourth air passage line  258 . Positioned intermediate each of the air passage lines is a check valve  260  which ensures that air can pass through the lines only in a single direction. 
     The primary components of the pneumatic pump system  45  having been described above, normal operation and use of the system will now be discussed. As identified above, pressurized CO 2  gas exits the second pressure regulator  28  and travels down supply line  42  to the pneumatic pump systems main gas supply line  242 . The main gas supply line  242  transports this gas to the master control valve  230  which, in turn, either directs this gas into the first gas supply line  232  or the second gas supply line  234 , depending upon the desired direction of travel of the second piston head  222 . For instance, if it is desired that the second piston head  222  travel toward the central dividing member  208  of the pump system  45 , the gas supplied by the main gas supply line  242  is directed into the second gas supply line  234  and, thereby, into the gas chamber  212  adjacent the second end  206  of the pump outer tube  202 . As this gas collects in the gas chamber  212 , its pressure urges the second piston head  222  toward the air side  198  (upward in FIG.  11 ). In that the second piston head  222  is fixedly connected to the first piston head  220  with the piston rod  214 , this axial displacement of the second piston head effects a similar axial displacement of the first piston head. As the first piston head  220  travels toward the first end  204  of the outer tube, the air in the air chamber  210  is forced outwardly from the outer tube and into the third air passage line  256  such that this air can travel through the check valve  260  and into the air output line  254 , and finally into one or more of the liquid containers  44  (FIG.  1 ). To facilitate this movement of air, and avoid the creation of a vacuum, fresh air is provided to the air chamber  210  behind the first piston head  220  with the second air passage line  252 . In particular, air from the atmosphere is taken in through the air filter  250  and supplied to this second air passage line  252  with the air supply line  248 . 
     Once the second piston head  222  within the gas side  196  of the system  45  reaches a point adjacent the central dividing member  208 , the piston head makes contact with the first proximity sensor  226 . In particular, the piston head depresses a valve needle  262  of the proximity sensor that sends a pneumatic signal along the first signal line  236  to the master control valve  230  to cause the control valve to redirect the high pressure gas supplied by the main gas supply line  242  from the second gas supply line  234  to the first gas supply line  232  so as to urge the second piston head  222  in the opposite direction. As the second piston head  222  travels toward the second end  206  of the pump  200 , the gas in front of the piston head is evacuated through the second gas supply line  234  (which previously had supplied high pressure gas to the gas chamber  212 ). The gas evacuated in this manner through the second gas supply line  234  is directed within the master control valve  230  to the vent line  234  such that this evacuated gas can pass through the check valve  246  and eventually through the diffuser  67  and out to the atmosphere (FIG.  1 ). As before, travel of the second piston head  222  effects similar travel of the first piston head  220 . Accordingly, the first piston head  220  now travels toward the central dividing member  208 . As the first piston head  220  travels in this direction, the air within the air chamber  210  is forced outwardly from the outer tube  202  this time through the fourth air passage line  258 , through its check valve  260 , and finally out through the air output line  254 . While the first piston head  220  travels in this direction, the roles of the first and second air passage lines  250  and  252  are reversed, i.e., the first air passage line  250  provides fresh air to the air chamber  210 , and the second air passage line  252  is closed by its check valve  260 . 
     Operating in this manner, the pneumatic pump system  45  supplies pressurized air to one or more of the containers  44  such that the liquid contained therein will be urged outwardly therefrom when this liquid is needed. In that air is supplied to these containers  44  as opposed to gas, carbonation of the liquid within these containers can be avoided. Accordingly, the pneumatic pump system  45  is particularly useful for pressurizing containers  44  that contain liquids for non-carbonated drinks such as juices and juice concentrates. It is to be noted, however, that the pneumatic pump system  45  can be used to pressurize all of the containers  44  of the system, if desired. 
     With reference back to FIG. 1, the first embodiment of the beverage dispensing system  10  can be used to dispense carbonated and noncarbonated mixed beverages, as well as any carbonated and noncarbonated unmixed beverages, in liquid form. To use the system  10 , the water tank  52  is filled with water via the water tank refill check valve  62  and water supply line  60 . Once the water tank  52  has been filled to an appropriate level, the three-way vent valve  63  is manually switched to the gas open position such that the gas chamber  58  of the tank and the supply line  50  are in open fluid communication with one another. 
     To initiate the dispensing system  10 , the operator opens the shut-off valve  22  of the gas storage tank  20  so that high pressure CO 2  gas flows to the three gas pressure regulators  26 ,  28 , and  30 . After passing through the first pressure regulator  26 , CO 2  gas flows into the carbonator tank  16 , raising the pressure within the tank to approximately between 90 psi to 110 psi. In addition, this gas is directed to the fourth pressure regulator  35  which then delivers the gas to the water level switch  40 . The gas supplied to the water level switch  40  is used, as needed, to send pneumatic pressure signals to the water valve  64 . At approximately the same time, the high pressure CO 2  gas also flows through the second and third pressure regulators  28  and  30 . After passing through the third pressure regulator  30 , the high pressure gas passes through the supply line  50 , through the three-way vent valve  63 , and into the gas chamber  58  of the water tank  52  to fill and pressurize the water within the tank. 
     As the CO 2  gas continues to flow into the gas chamber  58 , the water is forced out of the tank  52  and flows through the water supply line  60  to travel to both the carbonator tank water valve  64  and the water pressure regulator  72 . The water that passes through the water pressure regulator  72  is piped into and through the flat water supply pipeline  74  to be cooled by the cold plate  48  and, if desired, dispensed through the beverage dispensing valve  18 . 
     Assuming the carbonator tank  16  to initially not contain water, the float member  88  contained therein is positioned near the bottom of the tank and the water tank level switch  40  is in the activated position shown in FIG.  3 . Because the water tank level switch  40  is in this activated position, pneumatic pressure is provided to the water valve  64 , keeping it in the open position so that water can flow into the carbonator tank  16 . As the water continues to flow from the water tank  52  and fills all lines connected thereto, the pressure of the water begins to rise sharply. Eventually, the pressure of the water in the water chamber  56  and the lines in fluid communication therewith reach a pressure equal to that of the high pressure CO 2  gas contained in the gas chamber  58 . Accordingly, water enters the carbonator tank  16  at high pressure, typically between 195 psi to 200 psi. 
     Since the carbonator tank  16  is relatively small when compared to the CO 2  container and water tank, it fills quickly. Therefore, carbonated water is available soon after the system  10  is initiated. As such, the operator can use the beverage dispensing valve  18 , commonly referred to as a “bar gun,” to dispense either flat water supplied by the flat water supply line  74  or carbonated water supplied by the carbonated water supply line  82   
     Once the carbonator tank  16  is full, the water level switch  40  becomes oriented in the inactivated position (FIG.  4 ), thereby shutting-off the supply of gas to the water valve  64 . Not having the pressure signal needed to remain open, the water valve  64  closes, cutting the supply of water to the carbonator tank  16 . As the water level within the carbonator tank  16  is again lowered, the water level switch  40  is again activated, restarting the process described above. The system  10  therefore cycles in response to the volume of water contained in the carbonator tank. The cycle occurs repeatedly during use of the system  10 , until either the gas or water supplies are depleted. At this time, either or both may be refilled, and the system  10  reinitiated. 
     Occurring concurrently with the water pressurization and supply described above, the pressurization and supply of the liquid contained in the containers  44  is effected under the influence of pressurized CO 2  gas. First, CO 2  gas at approximately 45 psi travels from the supply line  42  directly to one or more containers  44 . Normally, these containers  44  will contain liquids that are to be used in carbonated drinks, such as soft drink syrups. When one of these liquids is selected by activating the appropriate control on the dispensing valve  18 , the supply line  47  is opened to the valve and the liquid flows from its container  44 , under the pressure of the CO 2  gas, to the dispensing valve. The CO 2  gas travelling along the supply line  42  also is directed to the pneumatic pump system  45  which, as described in detail above, pressurizes air and supplies it to selected containers  44 . Normally, these containers contain liquids used to make non-carbonated drinks such as juices and the like. The pump  200  of the pump system  45  will continue to cycle back and forth in response to the activation of the proximity sensors  226 ,  228  until equilibrium is reached between the air chamber  210  and the interior of the bottles  118  that are pressurized therewith. At this point, the pump  200  stalls and will remain so until a demand for more pressurized air is received (e.g. when an amount of liquid is dispensed from one of the containers  44 ). 
     So described, the beverage dispensing system  10  of the first embodiment can be used to dispense carbonated and non-carbonated drinks without the need for an external water source or electricity. Accordingly, the system is self-contained and, therefore, well-suited for portable beverage dispensing applications. 
     FIG. 12 is a schematic view of a second embodiment of a self-contained pneumatic beverage dispensing system  300 . Since the second embodiment is substantially similar in structure and function to the system  10  of the first embodiment except as to the source of water and the pressure levels provided to the various components, the following discussion of the second embodiment of the invention is focused on the water source  302  and these pressure levels. 
     In this second embodiment, the high pressure water tank  52  of the first embodiment is replaced with a low pressure water tank  304  and a high pressure water pump system  306  that includes a pneumatic water pump  308 . The low pressure water tank  304  has first and second chambers  310  and  312  that are separated by a pliable diaphragm  314 . Since a high pressure pump  308  is included in the system, the water within the water tank  304  need not be at high pressure. Accordingly, instead of being supplied with CO 2  gas at approximately between 195 psi to 200 psi, the water tank  304  is supplied with gas at pressures approximately between 25 psi to 60 psi. Since it will not be subjected to high pressure CO 2  gas, the low pressure water tank  304  can be constructed of mild steel as opposed to stainless steel which tends to be substantially more expensive. As with the water tank  52  of the first embodiment, pressurized water can leave the first chamber  310  of the tank through a water supply line  60 . In one direction, the pressurized water supplied by the water tank  304  flows to the pneumatic water pump  308  to fill the pump with water. In a second direction, the water flows through flat water line  74  to the cold plate  48 . 
     Instead of being directed to the water tank  304 , the high pressure gas supplied by supply line  50  is directed to a pneumatic water pump control valve  316 . As shown in FIG. 12, in addition to the supply line  50 , the control valve  316  is connected to a pump gas supply line  318 , and to first and second pneumatic signal lines  320  and  322 . The pump gas supply line  318  connects in fluid communication to the pneumatic water pump  308  at its first end  324 . The pneumatic signal lines  320 ,  322  connect to first and second piston sensors  136  and  328 , respectively. The first piston sensor  326  is mounted to the pump  308  adjacent its first end  324  and the second piston sensor  328  is mounted to the pump adjacent its second end  330 . Each of the piston sensors  326 ,  328  is connected to a sensor gas supply line  332  which is in fluid communication with the supply line  50   
     As shown in FIG. 13, the pneumatic water pump  308  comprises a piston cylinder  334  and a rodless piston head  336 . The rodless piston head  336  comprises a central magnet  338  that is positioned intermediate two piston end walls  340  and  342 . Located between the magnet  338  and each of the end walls  340 ,  342  are seals  344  and  346 . Typically, these seals  344 ,  346  comprise an inner resilient O-ring  348  and an outer lip seal  350 . Configured in this manner, the seals  344 ,  346  prevent fluids from passing between the piston head  336  and the piston cylinder  334 , but permit sliding of the piston head along the cylinder. 
     In an initial filled state, with the piston head  336  positioned adjacent the first end  324  of the pump, piston sensor  326  senses the proximity of the piston head due to the magnetic attraction therebetween. When such a condition is sensed, the sensor  326  is activated and sends a pneumatic pressure signal to the control valve  316 , causing the control valve to open. While in the open position, high pressure gas flows through the control valve  316 , along the pump gas supply line  318 , and into the gas side of the pump  308 . The high pressure gas ejects the water contained on the water side of the piston head  336 , eventually pressurizing the water to approximately between 195 psi to 200 psi. 
     From the pump  308 , the pressurized water flows to the carbonator tank  16  similarly as in the first embodiment. When nearly all of the water is driven out of the pump  308  with the piston head  336 , the second piston sensor  328  activates in similar manner to the first piston sensor  326 , and sends a pneumatic pressure signal to the control valve  316  that causes the valve to cut-off the supply of gas to the pump  308  and vent the pump cylinder  334  so that the relatively low pressure water can again fill the pump. Once the pump  308  is completely filled, the first piston sensor  326  is again activated, and the system cycles again. 
     Although the system  302 , as described above, is believed to be complete and effective, the system can further include a pump reset switch  352  and/or an accumulator tank  354 . As shown in FIG. 12, the reset switch  352  receives high pressure water from the pump  308  through water supply line  356 . The reset switch also receives low pressure CO 2  gas from the supply line  42  through gas supply line  358 . Linking the reset switch  352  and the pump control valve  316  is a pneumatic signal line  360  which connects to line  322 . So arranged, the pump reset switch ensures that there is adequate amount of carbonated water to meet demand. For instance, if the piston head  336  is positioned at some intermediate point along the length of its stroke and the carbonator tank  16  is filled, shutting off the water valve  64 , equilibrium can be achieved, dropping the pressure of the water, therefore indicating that the water pump  308  is not full. Upon sensing this water pressure drop, the reset switch  162  sends a pneumatic pressure signal to the control valve  316 , causing the valve to close and vent the gas pressure in the pump so that the pump can be refilled and a full piston stroke then executed. 
     Another optional component that ensures adequate supply of high pressure water is the accumulator tank  354 . The accumulator tank  354  contains an internal diaphragm (not shown) which separates a first chamber of the tank a second chamber of the tank. In the first chamber is a volume of nitrogen gas. In operation, the second chamber fills with high pressure water supplied by the pump  308 . As the accumulator tank  354  is filled, the nitrogen gas contained in the first chamber is compressed. In this compressed state, the gas can force the water out of the accumulator tank  354  during situations in which carbonated water demand is high and the pump  308  is in the refill portion of its cycle. 
     FIG. 14 illustrates a first alternative carbonator tank and filling system  362  for use in either of the above described dispensing system embodiments. The system  362  comprises a conventional electrically sensed, high pressure carbonator tank  364  and an electric power source  366 . Considered suitable for this application is any of the electrically sensed carbonator tanks produced by McCann. To ensure portability, the power source  366  typically comprises a battery. Electrically connected to the carbonator sensor (not shown) are both the power source  366  and a low voltage pneumatic interface valve  368 . The interface valve  368  is in fluid communication with both a source of pressurized CO 2  gas and a pneumatic water valve  370 . 
     When the electric sensors within the carbonator tank  364  detect that the carbonator tank is not full, the sensors electrically signal the interface valve  368 . This signal causes the valve  368  to open and thereby send a pneumatic pressure signal to the pneumatic water valve  370  to cause it to open so that the carbonator tank  364  can be refilled in the manner discussed above. 
     FIG. 15 illustrates a second alternative carbonator tank and filling system  372  for use with either the beverage dispensing system which comprises a conventional high pressure carbonator tank  374 . The carbonator tank  374  is mounted to a vertical surface with a spring loaded carbonator mounting bracket  376 . Coupled to this mounting bracket  376  is a pneumatic three-way valve  378  that is in fluid communication with a high pressure CO 2  gas supply line  380  and a pneumatic signal line  382  which, in turn, connected to a pneumatic water valve  384 . 
     When the carbonator tank  374  is empty, it is supported by the carbonator mounting bracket  376  in an upright orientation. While in this upright orientation, the pneumatic three-way valve  378  is open, thereby sending a pneumatic pressure signal to the water valve  384  to remain open. Once the tank  374  is nearly full, however, its weight overcomes the strength of the spring within the bracket  376 , causing the tank to tilt. This tilting action closes the three-way valve  378 , which, in turn, closes the water valve  384  and shuts-off the supply of pressurized water to the carbonator tank  374 . 
     While preferred embodiments of the invention have been disclosed in detail in the foregoing description and drawings, it will be understood by those skilled in the art that variations and modifications thereof can be made without departing from the spirit and scope of the invention as set forth in the claims.