Abstract:
A combined agitator ( 30 ), carbonator ( 10 ) and soda pump arrangement ( 23, 24 ) for dispensing beverages uses a magnetic drive coupling ( 28, 29 ). The carbonator coolant tank ( 15 ) in which the agitator ( 30 ) works has an optional ice bank chiller ( 20 ).

Description:
FIELD OF THE INVENTION 
     The present invention generally concerns beverage dispensing equipment and in particular such equipment having a combined agitator, carbonator and soda pump arrangement using a magnetic drive coupling. 
     BACKGROUND OF THE INVENTION 
     Beverage dispensing equipment relative to the provision of carbonated beverages is well understood. Such beverages may include a syrup mixed with carbonated water (also known as soda). Such equipment which provides for such beverages typically have associated with them a carbonator for mixing carbon dioxide gas with water. The carbonator body may have surrounding it a reservoir containing a chilled coolant. For example, the carbonator may be located within an ice bank cooled water bath which chills the carbonator and its contents as well as the water to be carbonated. As is known, the ice bank is formed on an evaporator located with the water bath which evaporator is cooled by the operation of a mechanical refrigeration system. Examples of such arrangements are described in GB 2 307 975A and U.S. Pat. No. 5,399,300. 
     In practice, the carbonator may be closely adjacent to or remote from the beverage dispense point i.e., the point where a valve or tap is operated to dispense the beverage into a glass or similar container from which the consumer will drink the beverage. If the carbonator is remote from the dispense point, the soda may be kept chilled on its journey from the carbonator by ensuring that the supply tube is held within a thermally insulating sleeve which is sometimes known as a python. 
     A continuing problem with prior art carbonators concerns their ability to rapidly form carbonated water of the desired level of carbonation to adequately provide for needed volumes thereof during periods of high drink demand. 
     A further problem concerns the ability of the cooling equipment to provide for good heat exchange between the ice bank and the carbonator tank and the water or syrup coils wherein the water in the bath serves as the thermal exchange medium there between. Typically, agitators are used to stir the water in the bath tank to ensure proper heat exchange between the water and the ice bank and, in turn, the carbonator and coils. However, an agitator includes a separate motor and presents further equipment and energy consumption cost. 
     Carbonators also require a water pump to pump the flat or non-carbonated water therein and to pump the carbonated water therefrom to the dispense point. Such pumps also represent further cost and complexity. 
     Accordingly, it would be desirable to have an improved carbonator that can produce large volumes of properly carbonated water. And it also would be desirable to accomplish the foregoing in a manner that provides for good heat exchange between the carbonator and the cooling medium there around and do so in a manner that is cost efficient. It would further be desirable to provide for such heat exchange and for the pumping of water to and from the carbonator that does not require separate motors for each such function. 
     BACKGROUND OF THE INVENTION 
     According to one aspect of the invention, a carbonator is provided for use in beverage dispense, said carbonator comprising: 
     means for retaining a first liquid to be carbonated, said retaining means essentially comprising a closed tank having associated an entry for said first liquid and an associated exit for said first liquid when carbonated; 
     means for admitting carbon dioxide gas under pressure into said retaining means; pump means for said first liquid located within said retaining means, said pump means having drive means located externally of said retaining means, said pump means being driven via a magnetic coupling between the pump means and the drive means; 
     a reservoir in which said retaining means is located, said reservoir being adapted to hold a second liquid which surrounds at least part of said retaining means, and agitation means located below the retaining means for agitating said second liquid, said agitation means being directly connected with the said drive means. 
     A passageway may be provided through the retaining means through which passes a shaft extending from the drive means to the agitation means. The drive means may be located above the retaining means. The magnetic coupling between the pump means and the drive means may comprise two components, one of which is within the retaining means and coupled with the pump impeller, with the other component extending within the reservoir below the retaining means. This second component is typically attached to the lower portion of the shaft. The agitation means for the second liquid is typically located on said shaft below said latter component of the magnetic coupling. Means may be provided attached to the pump impeller for agitating the first liquid within the retaining means. 
     Optionally, the reservoir may contain means for chilling the second liquid. Such chilling means may include the evaporator portion of a refrigeration circuit. The evaporator may be in the form of a coiled tube which extends around the inside perimeter of the reservoir. The refrigeration system may be adapted to create and maintain an ice bank around the inside perimeter of the reservoir. Alternatively, the second liquid may be recirculated through a python to a remote chiller from where the second liquid is returned to the reservoir. The reservoir may be of a depth which substantially enables the retaining means to be covered with the second liquid or for the liquid to extend over a substantial portion of the external surface area of the retaining means. Within the reservoir there may be means for circulating a further liquid product and maintaining said further product chilled. Such further product could include a fruit or cola syrup. 
    
    
     DESCRIPTION OF THE DRAWING 
     A more thorough understanding of the structure, function, operation, objects and advantages of the present invention can be had by reading the following detailed description of the preferred embodiment which refers to the following drawing: 
     FIG. 1 shows a schematic elevation partly in cross-section of f the carbonator of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     One embodiment of the invention will now be described, by way of example only, with reference to the accompanying FIG. 1. A carbonator of the present invention for use with an associated beverage dispenser has a carbonator body  10  of cylindrical shape and made from stainless steel. The carbonator body has an upper end cap  12  and a lower end cap  13  which together with the body  10  provide means for retaining a body of water  11  which is being carbonated. The lower end cap  13  is made of non-ferromagnetic material e.g. a plastics moulding, and the assembly is made pressure tight to accommodate the required degree of carbonation. Upper end cap  12  can also be made of plastic, as seen in U.S. Pat. No. 5,792,391, which patent is incorporated herein by reference thereto, and both caps  12  and  13  can be secured to carbonated body cylinder  10  as seen therein. 
     A central passageway having an annular wall  14  and a top fluid tight shaft seal  14   a  and a bottom fluid tight shaft seal  14   b,  extends vertically through the carbonator body  10 . The carbonator body  10  is located within a coolant reservoir  15 , the coolant typically being glycol or water based. The level of the coolant is shown by numeral  16 . 
     The carbonator body  10  has entry means  17  to enable fresh water to pass into the carbonator. An exit  18  for carbonated water extends through the wall of the lower end cap  13  and has tubing (shown schematically by dashed lines) which takes the carbonated water from the carbonator and transfers it to one or more associated beverage dispensers. A carbon dioxide gas inlet  19  is provided in the upper end cap  12  whereby carbon dioxide gas under pressure may be admitted into the carbonator body and into the water  11  retained within said body  10 . 
     As seen in FIG. 1, an optional evaporator  20  is used to chill and/or freeze the coolant adjacent the inner walls of reservoir  15 . This may create an ice bank whose inner perimeter is illustrated in dashed line at  21 . Optional product coils  22 , through which syrups or colas may pass and be chilled, are shown extending within the coolant in the reservoir  15 . 
     Within the annular carbonator body  10  is a pump housing  23  which is co-axial with central passageway  14 . Within pump housing  23  is a pump impeller  24 , again co-axial with central passageway  14 , which may be driven to pump soda water from carbonator body  10  via exit  18 . A vane  25  is attached to the pump impeller  24  so that it rotates with it to agitate the water  11  within carbonator body  10  to assist in the absorption of carbon dioxide. The pump impeller  24  is driven indirectly by a motor  26  positioned above the carbonator body  10 . A drive shaft  27  extends downwardly from motor  26  through central passageway  14  and through dynamic seals  14   a  and  14   b  to below the level of the lower end cap  13 . The indirect driving means is provided by magnetic drive components  28  and  29 , first component  28  of which is attached to drive shaft  27  and extends radially therefrom closely adjacent to and below the bottom surface of the lower end cap  13 . The second component  29  of the magnetic drive means extends annularly and is free to rotate within carbonator body  10  closely adjacent the upper surface of the lower end cap  13 . The pump impeller  24  is attached to the second magnetic drive component. The principles of operation of such magnetic drives are well known. 
     An agitator  30  for the second liquid, namely the coolant within reservoir  15 , is attached to the remote end of drive shaft  27  such that the agitator  30  is below the level of the first magnetic drive component  28 . Agitator  30  serves to homogenise the coolant and avoid stratification of such coolant into zones of differing temperature. It also serves to move the coolant relative to the surface of an ice bank when such is present within the reservoir and also to ensure that syrup within tubes  22  is maintained at a substantially constant temperature. 
     In operation, motor  26  operates to drive shaft  27  and to directly drive agitator blade  30  secured thereto. Rotation of shaft  27  also rotates magnetic drive component  28 , which then imparts rotation to drive component  29 . Drive component  29  then causes rotation of impeller  24  and agitator  25  attached thereto. The water in carbonator  10  is then carbonated by the mixing action of agitator  25  and is also pumped therein along line  17  and therefrom along line  18  by the action of impeller  24 . Thus, those of skill will appreciate that carbonator  10  can provide for agitation of the heat exchange fluid there around and for the agitation of the water and therein as well as for the necessary pumping of water therein and carbonated water there from through the use of a single motor  26 .