Abstract:
A pressure/vacuum converting machine converts a positive fluid pressure input into positive and negative fluid pressure outputs. The machine also stores energy from the positive fluid pressure input for driving additional fluid pressure outputs. In one application, the pressure/vacuum converter forms a part of a dispensing machine which employs the pressure of water delivered to the machine into positive and negative air pressures used to dispense a beverage.

Description:
BACKGROUND OF INVENTION  
       [0001]     This invention relates generally to powered actuators and more particularly to a pressure/vacuum converting machine which employs line fluid pressure to power the machine.  
         [0002]     Machines in the form of pumps for dispensing metered quantities of fluent material frequently employ an electric motor as the prime mover. The motor may be coupled to a hydraulic or pneumatic pump which powers operation of the machine, or it may directly drive a actuator acting on the fluid. One example of such a machine is a beverage dispensing machine of the type shown in co-assigned U.S. papent application Ser. No. 10/351,006, filed Jan. 24, 2003, the disclosure of which is incorporated herein by reference. A motor and accompanying equipment place certain limitations on the design of the dispenser. They require that the machine be connected to a source of electricity, and add to the cost of the dispenser, and also to the bulk of the dispenser. Moreover, the motor and accompanying equipment may generate significant acoustical noise in the operation fo the dispenser.  
         [0003]     Dispensers of the type just described also frequently have valves associated with them to control the flow of fluent material. For example if the dispenser mixes two liquids and then dispenses them, it may be necessary to route the liquid within the dispenser. That will typically require one or more valves to accomplish. The valves themselves must be driven. Conventional drivers for such valves include pneumatic cylinders and solenoids. Pneumatic cylinders require a source of compressed air (e.g., from a compressor driven by the electric motor mentioned above). Solenoids require connection to an electrical outlet. In either case, the cylinder or solenoid take up space in the dispenser housing.  
       SUMMARY OF THE INVENTION  
       [0004]     The machine of the present invention is able to eliminate a prime mover in the form of an electric motor. In at least one embodiment, no electricity is required to operate the machine. The machine takes advantage of energy in the form of line pressure of fluid. For example, utility water is kept under a certain pressure so that it will flow. The present invention is able to convert the energy associated with the line pressure into motion of the machine. In a particular embodiment where the machine is used to dispense a mixture of water from a utility supply with an additive, the line pressure may be used to power movement of measured quantities of water and liquid. Moreover, valves used to control the flow of fluent material may also be beneficially driven by the line pressure.  
         [0005]     In one aspect of the invention, a pressure/vacuum converting machine for converting an input force from an expandable bladder into at least one pneumatic actuation force comprises a pressure vessel adapted to receive at least a portion of the bladder therein. The bladder as received in the pressure vessel defines a gas volume not occupied by the bladder within the vessel. The gas volume of the pressure vessel decreases as the bladder expands thereby increasing the gas pressure in the gas volume. A pneumatic actuator is in fluid communication with the gas volume of the pressure vessel such that pressure in the gas volume drives operation of the pneumatic actuator.  
         [0006]     In another aspect of the present invention, a fluent material dispenser powered by fluent material from a source of fluent material under pressure to act upon a flexible container to dispense fluent material used to power the dispenser. The fluent material dispenser comprises a first pressure vessel sized and shaped to receive a first portion of the flexible container therein in sealing relation with the flexible container first portion to define a gas volume within the first pressure vessel. A second pressure vessel is sized and shaped to receive a second portion of the flexible container therein in sealing relation with the flexible container second portion. A valve selectively connects the first portion of the flexible container to the source of fluent material under pressure such that the first portion is capable of expanding into the first pressure vessel to reduce the gas volume and increase the gas pressure in the first pressure vessel. A pneumatic actuator in fluid communication with the gas volume of the first pressure vessel is adapted for employing energy from the increased gas pressure caused by expansion of the first portion into the first pressure vessel to deflect the second portion and move fluent material within the second portion. The pneumatic actuator is also capable of storing energy to act on the first portion of the flexible container to displace fluent material therefrom when the valve is closed, whereby fluent material is dispensed.  
         [0007]     In still another aspect of the present invention a method for dispensing fluent material using the pressure of fluent material from a source of fluent material under pressure comprises admitting fluent material under pressure into an elastic first bladder such that the first bladder expands in volume. Expansion of the elastic bladder is converted into positive gas pressure to drive a pneumatic actuator to effect one of expansion and compression of an elastic second bladder to move fluent material within the second bladder. Energy is stored from the positive gas pressure. Admission of fluent material under pressure into the first bladder is shut off. The pneumatic actuator is driven by the stored energy to compress the first bladder and to effect the other of expansion and compression of the second bladder for use in dispensing fluent material.  
         [0008]     In a further aspect of the present invention, a pneumatic valve system comprises a valve including a cylinder and a piston biased to one of a valve open and a valve closed position. A pneumatic actuator in fluid communication with the valve is capable of applying at least one of a positive and negative pressure to the valve. The actuator is connected to the valve to move the piston against its bias to the other of the valve open and valve closed positions upon application of said one pressure. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a perspective of an orange juice dispenser constructed according to the principles of the present invention;  
         [0010]      FIG. 2  is the perspective of  FIG. 1  with a front door of the dispenser removed;  
         [0011]      FIG. 3  is a front elevation of a flexible container of the present invention;  
         [0012]      FIG. 4  is a section taken in the plane including line  4 - 4  of  FIG. 3 ;  
         [0013]      FIG. 5  is a schematic of the dispenser prior to activation;  
         [0014]      FIG. 6  is the schematic of  FIG. 5  subsequent to activation;  
         [0015]      FIG. 7  is an enlarged, schematic longitudinal section of a pressure/vacuum converter of the present invention at one end of an outward stroke;  
         [0016]      FIG. 8  is the pressure/vacuum converter in an intermediate position; and  
         [0017]      FIG. 9  is the pressure/vacuum converter at an opposite end of its outward stroke. 
     
    
       [0018]     Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]     Referring now to the drawings and in particular to  FIGS. 1 and 2 , an orange juice dispenser constructed according to the principles of the present invention is indicated generally at  1 . The orange juice dispenser comprises a rectangular housing or cabinet  3  defining a compartment  5  containing flow control apparatus  7  constructed according to the principles of the present invention for dispensing a drink from a flexible container  9  acted upon by the flow control apparatus. The foregoing reference numerals designate their subjects generally. A stand  11  (which may be formed integrally with the cabinet  3 ) supports the cabinet in an elevated position above the stand providing a space for placing a cup C or other suitable container below an output nozzle  13  to receive the beverage dispensed (i.e., orange juice). Although the illustrated embodiments show the invention in the context of an orange juice dispenser, the invention may be used to dispense, or mix and dispense other liquid beverages (e.g., coffee), and non-consumable liquids (e.g., paint), as well as matter which is fluent, but not liquid.  
         [0020]     The cabinet  3  includes a front door  15  which is hinged to the remainder of the cabinet. The front door may be swung open to access the flow control apparatus  7  on the interior of the cabinet  3 . For simplicity and clarity of illustration, the front door  15  has been completely removed in  FIG. 2 . A button  17  on the front door  15  may be pressed to actuate the flow control apparatus  7  to dispense the beverage into the cup C. The drink dispenser  1  may operate to deliver a fixed volume of the beverage each time the button  17  is pressed. Of course, levers or other types of devices (not shown) for activating the dispenser may be employed.  
         [0021]     The flow control apparatus  7  is mounted on an upper slide and a lower slide (indicated generally at  19  and  21 , respectively), both of which are fixed to the cabinet  3  within the compartment  5 . Each slide  19 ,  21  includes telescoping sections which allow the flow control apparatus  7  to be moved out of the compartment  5  for servicing, such as by replacing the flexible container  9  with another flexible container (not shown, but of the same construction). A rectangular frame, generally indicated at  23 , is connected as by bolts to the slides  19 ,  21  and forms the basis for connection of the other components of the flow control apparatus  7 .  
         [0022]     A fixed shell member  25  is attached to the lower end of the frame  23  and a pivoting shell member  27  is attached by hinges to the fixed shell member for pivoting about a horizontal axis extending generally along the bottom edge of the fixed shell member  25  between a closed operating position and an open position. A pair of blocks  31  (only one is shown) mounted on an upper end of the fixed shell member  25  extend outwardly from the fixed shell member in the direction of the pivoting shell member  27 . The blocks  31  mount respective latch receptacles  33  (only one is shown) for releasably connecting respective latching mechanisms, generally indicated at  37 , attached to the pivoting shell member  27 . The latching mechanisms  37  each include a base  39 , a lever  41  pivotally mounted on the base operable to release the latching mechanism from the latch receptacle.  
         [0023]     The construction of the dispenser  1  is similar to that shown and described in co-assigned U.S. patent application Ser. No. 10/351,006. However, the pivoting shell member  27  provides a reaction surface for a lower portion of the flexible container  9 . No fluid pressure is applied to the flexible container through the pivoting shell member  27  in the illustrated embodiment, although such a construction is not excluded from the scope of the present invention. Other constructions for holding the flexible container  9  could be used without departing from the scope of the present invention. Among other things, it is envisioned that the flexible container could be sufficiently rigid to hold itself to the fixed shell member  25  using clips or the like (not shown) which do not completely cover one side of the lower portion of the flexible container  9 . In that event, the pivoting shell member  27  could be eliminated.  
         [0024]     Referring now to  FIGS. 3 and 4 , the flexible container of the present invention comprises first and second opposed elements shown in the form of a tray  47  and a cover sheet  49 . The tray and cover sheet define a reservoir cell  51 , a concentrate metering cell  53 , a water metering cell  55  and a mixing cell  57 . The tray  47  and cover sheet  49  are generally sealingly connected at the peripheries of the respective cells, and are unconnected where they oppose each other in the cells, defining a volume for receiving a fluent material. The cells  51 ,  53 ,  55 ,  57  are sealed off except where they communicate with certain passages defined in the flexible container  9 . A first passage  59  leads from the reservoir cell  51  to the concentrate metering cell  53 . A second passage  61  provides a path for concentrate from the concentrate metering cell  53  and water from the water metering cell  55  to the mixing cell  57 . A third or outlet passage  63  leads from the mixing cell  57  out of the flexible container  9 . A fourth or inlet passage  65  allows water to be introduced into the water metering cell  55  from a source of water (e.g., utility water supply) outside the flexible container  9  and outside the dispenser  1 . Although a utility or mains water supply is referred to herein, any suitable source of water under pressure may be used. The tray  47  and cover sheet  49  are sealed together along the side edges of the various passages  59 ,  61 ,  63 ,  65 . The tray  42  and cover sheet  49  are unsealed over the passages and where the passages intersect the various cells  51 ,  53 ,  55 ,  57 .  
         [0025]     The tray  47  is made (e.g., vacuum formed) from a relatively rigid plastic (e.g., polyethylene) which generally holds its shape after formation. However, it is to be understood that a flexible container which is flexible everywhere, such as a flexible bag (not shown) made of two sheets of flexible plastic, may be used with the present invention. A face  47 A of the tray  47  lies generally in a single plane with other portions recessed for use in forming the cells and passages of the flexible container  9 . More particularly, the tray  47  is formed with depressions  47 B of various sizes and shapes which form parts of the aforementioned cells  51 ,  53 ,  55 ,  57  and passages  59 ,  61 ,  63 ,  65 . These depressions  47 B generally hold their shape and position relative to the face  47 A after the tray  47  is formed. The cover sheet  49  is a sheet of flexible plastic which is capable of resiliently stretching. The cover sheet  49  is sealed in a suitable manner to the face  47 A of the tray  47 , but is unsecured to the tray where it is in registration with the depressions  47 B formed in the tray. In this way, the cells  51 ,  53 ,  55 ,  57  and passages  59 ,  61 ,  63 ,  65  are formed.  
         [0026]     Referring to  FIG. 4 , the portion of the cover sheet  49  defining part of the reservoir cell  51  is shown distended as it would be when filled with orange juice concentrate. As will become apparent, the flexibility and elasticity of the cover sheet  49  allows the orange juice concentrate and water to be metered and mixed within the flexible container  9 . The more rigid tray  47  serves as a frame for the container  9  so that it can generally hold its shape when filled with orange juice concentrate and shipped. This has advantages, including making the flexible container  9  more robust in shipping and handling, as well as making it easier to pack together with other flexible containers in a small space (not shown). Materials other than orange juice concentrate may be packaged in the flexible container  9 , including inedible materials such as paint. Further, a single flexible container (not shown) may package more than one material in their own reservoir cells.  
         [0027]     Referring now to  FIG. 5 , a schematic illustration of the flow control apparatus  7  of the present invention is shown to comprise a first pressure vessel  69  which is formed by a recess in the portion of the surface of the fixed shell member  25  which faces the concentrate metering cell  53  of the flexible container  9  when the container is received in the flow control apparatus  7  as shown in  FIG. 2 . A second pressure vessel  71  is formed by another recess in the fixed shell member  25  facing the water metering cell  55  of the flexible container  9 , and a third pressure vessel  73  is formed by yet another recess facing the mixing cell  57 . An O-ring or other suitable sealing member (not shown) is held by the fixed shell member  25  in position around the periphery of each of the recesses. There is one O-ring for each recess, although a greater or lesser number of O-rings could be used within the scope of the present invention. Thus when the pivoting shell member is closed, it presses the cover sheet  49  of the flexible container  9  tightly against the O-ring so that each O-ring and the corresponding cell of the flexible container form a gas-tight seal of the respective pressure vessel  69 ,  71 ,  73 .  
         [0028]     The flow control apparatus  7  further includes a first pneumatic valve  77  mounted on the fixed shell member  25  and arranged for selectively closing and opening the first passage  59  from the reservoir cell  51  to the concentrate metering cell  53 . The valve  77  operates to close the first passage  59  by extending to engage the cover sheet  49  and deflect it downwardly into the depression  47 B in the tray  47  which forms the first passage. The cover sheet  49  stretches and resiliently deforms so that the first passage  59  is occluded and no concentrate may pass from the reservoir cell  51  to the concentrate metering cell  53 . When the first pneumatic valve  77  is retracted, the cover sheet  49  resiliently resumes its original condition spaced from the tray  47  so that concentrate may move through the first passage  59 . It is noted that gravity is used to feed concentrate to the concentrate metering cell  53  in concert with the vacuum applied by expansion of the concentrate metering cell  53 . However, it is envisioned that pressure could be applied to the reservoir cell  51  to facilitate flow of viscous fluent materials.  
         [0029]     A second pneumatic valve  79  is located by the fixed shell member  25  to engage the cover sheet  49  over second passage  61  when the valve is in its closed position to occlude the second passage and prevent orange juice concentrate and water from entering the mixing cell  57 . A third pneumatic valve  81  is located by the fixed shell member  25  to deform the cover sheet  49  into the third passage  63  in a closed position of the valve. Closure of the third passage  63  prevents the concentrate and water mixture from passing out of the mixing cell  57  to the outlet nozzle  13  ( FIG. 2 ). The operation of the second and third pneumatic valves  79 ,  81  to occlude the second and third passages  61 ,  63  is substantially the same as for the first pneumatic valve  77 . It is noted that the first, second and third pneumatic valves  77 ,  79 ,  81  all are spring-biased to their closed positions. All of the pneumatic valves are in fluid communication with an air line branch  83 . The details of their pneumatic actuation will be described below.  
         [0030]     A first mechanical valve  87  is positioned for engagement with the cover sheet  49  over the fourth (inlet) passage  65  to deflect the cover sheet into the fourth passage to prevent the flow of water into the water metering cell  55 . The valve  87  is schematically illustrated as being attached to an inlet lever  89  mounted on a first pivot  91 . A spring  93  urges the inlet lever  89  to a position in which the valve  87  is closed. A second mechanical valve  95  is arranged for engaging the cover sheet  49  over a branch  61 A of the second passage  61  leading from the water metering cell  55  to deform the cover sheet into the second passage branch and prevent water from exiting the water metering cell  55  in the second passage. The second mechanical valve  95  is schematically illustrated as being mounted by a spring  97  to an outlet lever  99  mounted on a second pivot  101 . The spring  97  biases the outlet lever  99  and valve  95  to an open position permitting flow of water out of the water metering cell  55  into the second passage  61  and to the mixing cell  57 . A catch  103  is located adjacent to an end of the outlet lever  99  on the opposite side of the second pivot  101  from the second mechanical valve  95 . The catch  103  is mounted for pivoting and has a notch  103 A which captures the end of the outlet lever  99  when it pivots to a closed position ( FIG. 6 ). A spring  105  urges the catch  103  to pivot counterclockwise (as oriented in  FIG. 5 ) to capture and hold the end of the outlet lever  99  in the notch  103 A. A linkage, schematically represented by a single link  107  in  FIG. 5 , connects the outlet lever  99  to the inlet lever  89  so that pivoting of one produces pivoting of the other, as will be more fully described.  
         [0031]     The second pressure vessel  71  (associated with the water metering cell  55 ) is connected by a conduit  111  to a pressure/vacuum converter (indicated generally at  113 ), and forms part of the pressure/vacuum converter. Enlarged, fragmentary views of the pressure/vacuum converter  113  in different stages of operation are shown in  FIGS. 7-9 . The pressure/vacuum converter  113  includes a first cylinder  115  connected to the conduit  111  for fluid communication with the second pressure vessel  71  and a second cylinder  117  mounted generally co-axially with the first cylinder. A piston generally indicated at  119  includes a first head  121  located in the first cylinder  115  and a second head  123  in the second cylinder  117  connected to the first head by a cylindrical tube  125 . Thus, the piston  119  of the illustrated embodiment is essentially a hollow cylinder. The first head  121  mounts an O-ring  127  which engages the inner surface of the first cylinder  115  in sliding, sealing engagement. Several O-rings are shown and described in the illustrated embodiment, it being understood that other suitable sealing arrangements may be employed without departing from the scope of the present invention. The O-ring  127  and first piston head  121  fluidically divide first cylinder  115  into a first region  129  (corresponding to the portion of the interior of the cylindrical tube  125  located within the first cylinder  115 ), and a second region  131  (see  FIG. 8 ).  
         [0032]     A leg  133  extends from a peripheral edge of the second piston head  123  and through the second cylinder  117  to a location exterior of the second cylinder. The end of the leg  133  has an outwardly projecting foot  135 . The leg  133  and foot  135  move conjointly with the second head  123 . When the piston  119  reaches the position illustrated in  FIG. 6 , the foot  135  engages the catch  103 . Further movement of the piston  119  in the outward stroke pivots the catch  103  in a clockwise direction against the bias of the spring  105 . The end of the outlet lever  99  is released from the notch  103 A. The spring  97  associated with the second mechanical valve  95  moves the outlet lever  99  back to the position shown in  FIG. 5 . This also allows the spring  93  to move the first lever  89  and first mechanical valve  87  from the position shown in  FIG. 6  back to the  FIG. 5  position.  
         [0033]     The second cylinder  117  includes a central column  139  which extends into the first cylinder  115  and terminates in a disk-shaped divider  141  supported by the column and separating the first cylinder  115  and the second cylinder. The central column  139  extends through the second piston head  123  in an opening containing an O-ring  143  (or other suitable seal) in sliding, sealing engagement with the central column. The periphery of the second piston head  123  mounts another O-ring  145  which is capable of slidingly and sealingly engaging an interior surface of the second cylinder  117 . The sealing connection of the second piston head  123  with the interior surface and the central column  139  allows the second piston head to fluidically divide the second cylinder  117  into a first region  147  and a second region  149  ( FIG. 8 ). It is noted that the second region  149  is defined within the piston  119  as it moves into the second cylinder  117 .  
         [0034]     As will be described more fully below, the seal between the second piston head  123  and the second cylinder  117  is selectively broken in operation. For this purpose, a first arcuate channel  153  in the inner surface of the second cylinder  117  extends in a circumferential direction of the second cylinder near the first cylinder  115 . An arcuate slot  154  in the second cylinder  117  near the first arcuate channel  153  opens to the ambient pressure air surrounding the second cylinder. A second arcuate channel  155  is located near end wall  157  of the second cylinder  117 . A conical spring  159  is located in the second cylinder  117  between the second piston head  123  and the end wall  157  of the second cylinder opposite the first cylinder  115 . The conical spring  159  biases the piston  119  to the position shown in  FIG. 7 .  
         [0035]     The divider  141  mounts an O-ring  161  in a circumferential surface for sliding and sealing engagement with an inner surface of the cylindrical tube  125  of the piston  119 . The divider  141  acts like a third piston head, dividing the interior of the piston  119  two regions (corresponding to the first region  129  of the first cylinder  115  and the second region  149  of the second cylinder  117 ). The seal of the O-ring  161  is selectively broken in operation, as will be described hereinafter. In that regard, the inner surface of the cylindrical tube  125  is formed with a first arcuate channel  163  extending in a circumferential direction near the first piston head  121 , and a second arcuate channel  165  near the second piston head  123 . It will be understood that the interior of the cylindrical tube  125  of the piston  119  acts as a third cylinder in the pressure/vacuum converter  113 . The central column  139  has two axially extending passages which open through the end wall of the second cylinder  117 . A first of the passages  167  also opens through the divider  141  into the first region  129  of the piston  119 , continuously providing fluid communication between the first region and atmosphere. A second of the passages  169  turns through 180° within the divider  141  to open into the second region  149  of the second cylinder  117 .  
         [0036]     A first air line  171  is connected to the second passage  169  of the pressure/vacuum converter  113  and extends to the first pressure vessel  69  and to all three of the pneumatic valves  77 ,  79 ,  81  by way of the branch  83  of the air line ( FIG. 5 ). The first air line  171  is in fluid communication with the second region  149  of the second cylinder  117 . Fluid pressure communicated through the first air line  171  operates on the concentrate metering cell  53  of the flexible container  9  and controls operation of the pneumatic valves  77 ,  79 ,  81 . It may be seen that the first air line branch  83  enters the first pneumatic valve  77  at a location behind a head  77 A of the valve. Thus when the first air line  171  and branch  83  experience positive pressure, a spring  77 B of the valve  77  is allowed to close the first pneumatic valve, shutting off the flow of concentrate from the reservoir cell  51  to the concentrate metering cell  53 . Vacuum pressure in the first air line branch  83  results in the head  77 A of the first pneumatic valve  77  being moved to the open position against the bias of the spring  77 B so that concentrate may flow from the reservoir cell  51  to the concentrate metering cell  53 . The second pneumatic valve  79  connects to the branch  83  of the first air line  171  at a location on an opposite side of a head  79 A of the valve from a spring  79 B. Accordingly, positive pressure in the first air line  171  results in the second pneumatic valve  79  being opened. Vacuum pressure in the first air line branch  83  closes the valve in concert with the spring  79 B. The third pneumatic valve  81  is connected to the branch  83  of the first air line  171  in the same way as the first (on the same side of a head  81 A of the valve as a spring  81 B), and operates in the same fashion in response to positive and negative air pressure in the first air line branch  83 .  
         [0037]     A second air line  173  is connected to the second cylinder  117  in an opening  175  in the end wall  157  of the second cylinder so that the second air line communicates with the first region  147  of the second cylinder (see  FIG. 7 ). The second air line  173  extends to the third pressure vessel  73 . It will be apparent that positive and negative air pressure in the second air line  173  will operate on the mixing cell  57  of the flexible container  9 . Although the lines are referred to as containing “air”, any gas or other fluent material capable of transmitting pressure to the various components could be used without departing from the scope of the present invention.  
         [0038]     Having described the construction of the dispenser  1  and its flow control apparatus  7 , its operation to dispense a metered quantity of orange juice mixed from concentrate and utility water will be described. It is noted that the dispenser  1  operates without requiring electricity. As an initial matter, a flexible container  9  previously packaged with orange juice concentrate will be installed in the dispenser. The door  15  of the dispenser  1  is opened and the flow control apparatus  7  is moved out using the slides  19 ,  21  ( FIG. 2 ). The pivoting shell member  27  is unlatched and swung down so that a lower portion of the flexible container  9  may be placed against the fixed shell member  25 . The flexible container  9  is hung on the frame  23  so that it remains in this position. The pivoting shell member  27  is swung back up and latched to hold the flexible container  9  securely against the fixed shell member  25  and promote sealing of the flexible container around the pressure vessels  69 ,  71 ,  73  defined in the fixed shell member  25 . In this installation process, the flexible container  9  is attached to a utility water line (not shown). The flexible container  9  is hooked up to the output nozzle  13  and the flow control apparatus  7  slides back into the dispenser compartment  5 . The door  15  is shut and the flow control apparatus  7  is cycled a as necessary so that a diluted volume of orange juice is held in the mixing cell  57 . The dispenser  1  is ready for operation.  
         [0039]     Someone desiring orange juice places the cup C below the output nozzle  13  of the dispenser and presses the button  17 . Prior to the button being depressed, the configuration of the flow control apparatus  7  is as shown in  FIG. 5 . The first mechanical valve  87  is closed, preventing water from the water line and fourth (inlet) passage  65  from entering the water metering cell  55 . The second mechanical valve  95  is open. The conical spring  159  of the pressure/vacuum converter  113  urges the piston  119  so that the first head  121  abuts an end wall  177  of the first cylinder  115 , applying a positive gas pressure to the second pressure vessel  71  and flexible cover sheet  49  over the water metering cell  55 , which collapses the cover sheet against the tray  47 .  
         [0040]     The first air line  171  (and branch  83 ) is at ambient pressure. Referring to  FIG. 7 , the second passage  169  and second region  149  of the second cylinder  117  are in fluid communication with the first region  129  of the first cylinder  115  because the O-ring  161  of the divider  141  is in registration with the second arcuate channel  165  of the piston  119 . The first region  129  is continuously vented to atmosphere by the first passage  167 . Therefore, the air line  171  and branch  83  are also at atmospheric pressure. In that condition, all of the pneumatic valves  77 ,  79 ,  81  are closed and neutral pressure is applied to the concentrate metering cell  53  in the first pressure vessel  69 . The first region  147  of the second cylinder  117  and second air line  173  are also vented to atmosphere in this position. More specifically, the first region  147  (to which the second air line  173  is connected) communicates with ambient pressure surrounding the pressure/vacuum converter  113  because the O-ring  145  associated with the second piston head  123  is in registration with the first arcuate channel  153  of the second cylinder  117 . Thus, air is able to pass the O-ring  145  into the first region  147  to maintain the region at atmospheric pressure. As a result, no positive or vacuum pressure is applied via the second air line  173  to the third pressure vessel  73  or to the cover sheet  49  overlying the mixing cell  57 .  
         [0041]     As the button  17  is depressed, the outlet lever  99  is pivoted clockwise (in the orientation shown in  FIG. 5 ) from the  FIG. 5  position to the  FIG. 6  position. One end of the outlet lever  99  pushes the catch  103  to pivot clockwise against the bias of the spring  105  until the end is aligned with the notch  103 A. The spring  105  then moves the catch  103  counterclockwise so that the end of the outlet lever  99  is captured in the notch  103 A, holding the outlet lever in position. The movement of outlet lever  99  brings the second mechanical valve  95  into engagement with the second passage  61  to prevent fluid from exiting the water metering cell  55 . At the same time the outlet lever  99  is pivoting, link  105  transfers this motion to inlet lever  89 , causing it to pivot in the clockwise direction and move the first mechanical valve  87  away from the inlet passage  65 .  
         [0042]     The opening of inlet passage  65  allows water under, for example, normal water main pressure, to enter the water metering cell  55 . The water fills the cell  55  and distends the portion of the cover sheet  49  defining part of the water metering cell  55  into the second pressure vessel  71 . In the illustrated embodiments, the water metering cell  55  of the flexible container  9  constitutes “a first bladder” and the cover sheet  49  is the portion of the first bladder which expands into the second pressure vessel  71 . The concentrate metering cell  253  constitutes “a second bladder” and the cover sheet  49  is the portion of the second bladder which expands into the first pressure vessel  69 . It is to be understood that a bladder within the scope of the present invention may have other configurations. The movement of the cover sheet  49  into the second pressure vessel  71  causes the air pressure in the vessel to increase. The higher air pressure is communicated to the second region  131  of the first cylinder  115  through conduit  111  to the first head  121  of the piston  119 . The piston begins to move to the right (in the orientation of  FIGS. 5-9 ) against the bias of the conical spring  159  as air flows into the second region  131  of the first cylinder  115  from the second pressure vessel  71 .  
         [0043]     Movement of the piston  119  from the initial position shown in  FIGS. 5 and 7  causes the second piston head  123  and O-ring  145  to move out of registration with the first arcuate channel  153  in the second cylinder. As may be seen in  FIG. 8 , the O-ring  145  engages the interior wall of the second cylinder  117 , fluidically isolating the first region  147  of the second cylinder from ambient. Accordingly, air pressure builds in the first region  147  and this is communicated by the second air line  173  to the third pressure vessel  73 . The pressure deforms the cover sheet  49  against the tray  47  in the mixing cell  57  so that a mixture of orange concentrate and water (i.e., ready to drink orange juice) is forced out of the mixing cell  57 , through the outlet passage  63 , to the nozzle  13  and into the waiting cup C. The mixing cell  57  is sized so as to dispense an amount of orange juice (e.g., 6 oz.) suitable for a single serving. Of course, the mixing cell  57  and dispenser could be configured to dispense any suitable amount. In the following description, it will become apparent how the mixture of water and orange juice came to be in the metering cell  57  for dispensing to the cup C.  
         [0044]     Referring to  FIGS. 6 and 8 , the travel of the piston  119  to the right moves the cylindrical tube  125  of the piston so that the divider  141  and O-ring  161  are out of registration with the second arcuate channel  165  in the piston. The O-ring  161  now seals with the cylindrical tube  125  around the full circumference of the O-ring. The second region  149  is fluidically isolated from ambient, and begins to expand in volume. The expansion produces a vacuum pressure within the second region  149  which is communicated to the first air line  171  by way of the second passage  169 . The first air line  171  transmits the vacuum pressure to the first pressure vessel  69  and to the portion of the cover sheet  49  defining part of the concentrate metering cell  53 . The part of the cover sheet  49  associated with the concentrate metering cell  53  expands into the first pressure vessel  69  for drawing concentrate from the reservoir cell  51  into the concentrate metering cell. The amount of concentrate drawn into the metering cell  53  is determined by the volume of the recess  47 B in the tray  47  plus the volume of the first pressure vessel  69 . In this way, a metered dose of orange juice concentrate is measured out for subsequent mixing and dispensing by the dispenser  1 .  
         [0045]     The vacuum pressure applied to the first air line  171  is used to open the first passage  59  and the outlet passage  63 . The vacuum pressure is communicated to branch  83 , which is connected to the pneumatic valves  77 ,  79 ,  81 . The first pneumatic valve  77  opens upon application of vacuum pressure against the bias of the spring  77 B to open the first passage  59 , allowing concentrate to flow from the reservoir cell  51  to the metering cell  53 . The vacuum pressure in the branch  83  causes the third pneumatic valve  81  to open so that the mixture of orange juice concentrate and water can pass out of the mixing cell  57  through the outlet passage  63  to be dispensed. However, the connection of the branch  83  to the second pneumatic valve  79  causes the valve to remain closed so that concentrate from the concentrate metering cell  53  and water from the water metering cell  55  cannot flow into the mixing cell  57 .  
         [0046]      FIG. 6  illustrates the pressure/vacuum converter  113  as the piston  119  nears the end of its (outward) stroke to the right (as oriented in  FIG. 6 ). The foot  135  of the leg  133  extending from the second piston head  123  of the piston  119  is shown just as it engages the catch  103 . Continued movement to the right to the end of the stroke of the piston (shown in  FIG. 9 ) moves the catch  103  up against the bias of the spring  105  so that the end of the outlet lever  99  moves out of the notch  103 A of the catch. The spring  97  of the second mechanical valve  95  then causes the outlet lever  99  to pivot counterclockwise back to the  FIG. 5  position. The second mechanical valve  95  moves to an open position so that water is permitted to move out of the water metering cell  55 . Movement of the outlet lever  99  is actuated by the spring  93  of the inlet lever  89  through the link  107 . The outlet lever  89  also pivots in a counterclockwise direction to close the fourth passage  65  so that mains water is prevented from flowing into the water metering cell  55 . At this time, a vacuum is being applied to the concentrate metering cell  53  and water metering cell  55  so that there is substantially no flow of concentrate or water out of either cell.  
         [0047]     When the piston  119  reaches the end of its rightward stroke as shown in  FIG. 9 , the conical spring  159  is pushed nearly flat against the end wall  157  of the second cylinder  117 . The O-ring  145  on the second head  123  of the piston  119  is aligned with the second arcuate channel  155  in the interior wall of the second cylinder  117 . The first region  147  and second air line  173  are now open to the ambient pressure because air can pass around the second piston head  123  and O-ring  145  in the second arcuate channel  155  and thence through the arcuate slot  154 . The pressure in the first region  147  and second air line  173  returns from a positive pressure to ambient. Accordingly, the air pressure in the third pressure vessel  73  over the mixing cell  73  is relieved and the cover sheet  49  moves back to a relaxed configuration spaced from the tray  47 .  
         [0048]     The first arcuate channel  163  in the cylindrical tube  125  of the piston is aligned with the O-ring  161  of the divider  141  at the right end of the piston stroke ( FIG. 9 ). This places the second region  149  of the second cylinder  117  and the first air line  171  in communication with air at ambient pressure by way of the first passage  167  in the column  139 . Air is able to flow around the O-ring  161  in the first arcuate channel  163  into the second region and into the first air line  171  via the second passage  169  in the column  139 . Vacuum pressure is relieved from the first pressure vessel  69  and concentrate metering cell  53  which is now filled with orange juice concentrate. Ambient pressure is communicated through the branch  83 , so that the first pneumatic valve  77  is pushed closed by the spring  77 B, closing the first passage  59  from the reservoir cell  51 . The second pneumatic valve  79  remains closed even though the vacuum pressure under the head  79 A is removed because of the bias of the spring  79 B. The third pneumatic valve  81  closes under the force of its spring  81 B so no additional liquid from the mixing cell  57  is dispensed.  
         [0049]     The conical spring  159  begins to push the piston  119  back to the left (as oriented in  FIGS. 5-9 ) from the position shown in  FIG. 9 . As the second head  123  of the piston  119  moves away from the end wall  157 , the O-ring  145  moves out of registration with the second arcuate channel  155  of the second cylinder  117 , again sealing the first region  147  of the second cylinder from atmosphere. The first region  147  expands in volume, creating a vacuum in the region which is communicated by way of the second air line  173  to the third pressure vessel  73 . The part of the cover sheet  49  which defines a portion of the mixing cell  57  expands into the third pressure vessel  73  to draw in concentrate and water from the concentrate metering cell  53  and water metering cell  55  (respectively).  
         [0050]     As the first head  121  of the piston  119  moves in a return stroke from the  FIG. 9  position back toward the  FIG. 8  position, the volume of the second region  131  of the first cylinder  115  is reduced. Therefore, pressure is applied through the conduit  111  to the second pressure vessel  71  and against the portion of the cover sheet  49  forming part of the water metering cell  55 . The cover sheet  49  is pushed, as the piston  119  progresses further to the left, down against the tray  47  in the region of the water metering cell  55 , causing water to be forced out of the cell, into the second passage  61  and to the mixing cell  57 .  
         [0051]     Movement of the piston  119  to the left also causes the first arcuate channel  163  to be moved out of registration with the O-ring  161  of the divider  141 . The second region  149  of the second cylinder  117  is again sealed from ambient so that continued movement of the piston  119  causes fluid pressure to build in the second region. This pressure is communicated via the second passage  169  in the column  139  to the first air line  171  and the first pressure vessel  69 . The part of the cover sheet  49  which defines a portion of the concentrate metering cell  53  is collapsed toward the tray  47  of the flexible container  9 . Orange juice concentrate is thus forced out of the concentrate metering cell  53  into the second passage  61  and to the mixing cell  57 . The concentrate mixes with the water from the water metering cell  55  as both travel to the mixing cell in the second passage  61  at substantially the same time. Thus, it is not necessary for any additional mixing to occur within the mixing cell  57 .  
         [0052]     As the piston  119  reaches the end of its return stroke, the O-ring  145  on the second head  123  comes into alignment with the first arcuate channel  153  of the second cylinder  117 . The first region  147  of the second cylinder is again able to communicate with ambient pressure through the first arcuate channel  153  and arcuate slot  154 . Vacuum pressure in the first region  147  and in the second air line  173  is relieved. The mixing cell  57  is also no longer subject to vacuum pressure. However, the mixed orange juice is not dispensed because the third pneumatic valve  81  remains closed, and as will be momentarily described, the second pneumatic valve  79  also closes. Thus, the orange juice is held in the mixing cell  81  pending the next activation of the dispenser  1 .  
         [0053]     The end of the return stroke of the piston  119  also places the second arcuate channel  165  in the cylindrical tube  125  of the piston in registration with the O-ring  161  of the divider  141 . The second region  149  of the second cylinder  117  communicates with ambient pressure by way of the second arcuate channel  165  and the first passage  167  in the column. The positive pressure in first air line  171  is also relieved to ambient. The portion of the cover sheet  49  associated with the concentrate metering cell  53  may then return under its own resiliency to a relaxed position from a position abutting the tray  47  in the recess  47 A defining part of the concentrate metering cell. A return to ambient pressure in the branch  83  of the first air line  171  has no effect on the first pneumatic valve  77  which remains closed because of the force of the spring  77 A, or on the third pneumatic valve  81  which remains closed under the force of the spring  81 B. The second pneumatic valve  79  moves from an open position by operation of the spring  79 B as pressure is relieved under the head  79 A to a closed position blocking entry of liquid into the mixing cell  57 . The dispenser  1  is now ready to dispense mixed orange juice when the button  17  is depressed.  
         [0054]     In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.  
         [0055]     When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.  
         [0056]     As various changes could be made in the above without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.