Low cost beverage carbonating apparatus and method
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to beverage dispensing equipment and, in particular, to carbonating systems for beverage dispensing apparatus. 
     2. Background of the Invention 
     Post-Mix beverage dispensing equipment generally includes a carbonating tank for producing carbonated water. Such carbonating tanks typically have a still water inlet and a carbon dioxide inlet, as well as a carbonated water outlet for delivery of the carbonated water to a dispensing valve or valves. A high level of carbonation is generally desirable and a water pump is often employed for pumping the still water into the carbonation tank to provide the pressure head necessary for adequate carbonation. In high volume beverage dispensing environments, such as bottling plants or fast food restaurants, the size or cost of equipment to pressurize the carbonation tank is not a significant factor. However, beverage dispensing equipment is increasingly finding applications in low volume environments, such as private offices, and small retail outlets. The cost and size of equipment designed for such applications is always of prime concern. Therefore, a beverage dispensing apparatus that provides for high levels of carbonation, yet at a cost substantially lower than through the use of conventional carbonating systems, would be highly desirable. 
     SUMMARY OF THE INVENTION 
     The carbonating system of the present invention includes a pivotally mounted carbonating tank having a water inlet, an inlet for connecting to a pressurized source of carbon dioxide, a carbon dioxide vent outlet, and a carbonated water outlet. An electric motor is connected to the tank by an off-set or rocking mechanism for imparting a regular synchronous wave movement to the water in the tank. 
     As is known in the art, agitation of carbonated water results in release of the carbon dioxide dissolved therein. However, in the present invention the carbonation levels were found to be significantly improved by a gentle rocking motion being imparted to the carbonator and, hence the water contained therein. Specifically, a wave motion is created that provides for increased carbonation of the water above what would be provided by the pressure of the carbon dioxide alone. 
     As is known in the art, water is more easily carbonated at lower temperatures. Thus, in the preferred form of the present invention, the electric motor that imparts the motion to the carbonator also includes a fan for providing a circulation of cooled air from an evaporator over the pivotally mounted carbonating tank. As a further cooling strategy, the carbonating tank water inlet is connected to a source of pre-cooled water, such as heat exchange tubing extending in a serpentine fashion through an ice bank. The use of pre-cooled water further enhances the ability of the present invention to attain satisfactory levels of water carbonation. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     A better understanding of the structure, operation, and objects and advantages of the present invention can be had in view of the following detailed description, which refers to the following figure, wherein: 
     FIG. 1 shows a schematic representation of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The carbonating apparatus of the present invention is seen in FIG. 1 and generally referred to by the numeral 10. Carbonating apparatus 10 includes a carbonator 12 and a pivotal mounting means 14 secured to the rigid structure of apparatus 10, such as a wall of a housing 16, shown in phantom outline. Carbonator 12 includes a water inlet 18, a carbon dioxide inlet 20, a carbonated water outlet 22, and a carbon dioxide vent outlet 24. An electric motor 26 includes a reduction drive 28 for connecting to a reciprocating means 30, which reciprocating means 30 is secured to carbonating tank 12. Motor 26 further includes a fan 32 being positioned adjacent an evaporator or cooling coil 34. As is understood by those of skill in the art, evaporator 34 is connected to a further refrigeration apparatus, such as a compressor and condenser (not shown). Vent outlet 24 includes a carbon dioxide vent solenoid 36. Inlet 20 includes a carbon dioxide control valve 38, and is connected to a source of pressurized carbon dioxide (not shown). Water inlet 18 includes a check valve 40 which is connected to a pre-cooling tank 42. Tank 42 is, in turn, connected to a source of potable water (not shown). Tank 42 is cooled, as for example, by placement in a refrigerated air space. Carbonated water outlet 22 is connected to a plurality of beverage or carbonated water dispensing valves (not shown). 
     A control 44 is connected to an upper liquid level switch 46 and a lower liquid level switch 48. Control 44 is also connected to vent solenoid 36, carbon dioxide solenoid 38, a manual regeneration switch 50, and a low carbonated water indicator light 52. 
     In operation, cooling tank 42 provides for the delivery of precooled water through inlet 18 into tank 12. As is understood in the art, check valve 40 prevents the reverse flow of carbonated water from tank 12 through inlet 18 towards the potable water source. When a sufficient volume of carbonated water has been withdrawn from carbonating tank 12, as sensed by low level sensor 48, control 44 closes carbon dioxide solenoid 38 and opens vent solenoid 36. As the water pressure from the potable water source is typically much lower than the carbon dioxide gas pressure, it can be appreciated that the coordinated closing of valve 38 and opening of valve 36 will permit the flow of water into tank 12. When sensor 46 indicates a sufficient volume of water in tank 12, control 44 then provides for the closing of valve 36 and the opening of valve 38. 
     Operation of motor 26, through reduction drive 28, serves to provide for a relatively slow oscillating or reciprocating movement of tank 12 about pivot 14. Thus, the carbon dioxide and water are gently mixed, in a manner below the level of agitation that would result in a release of carbon dioxide from the water, that instead provides for facilitating or enhancing the carbonation level of the resulting carbonated water. For example, in a cylindrical carbonation tank having an approximate internal volume of 3.5 liters, it was found, that pivoting movement about one end thereof through a total arc of approximately 30 degrees at 60 cycles per minute provided for a carbonation level of 3.8 volumes at 38 degrees temperature. One cycle being travel of the carbonator from, for example, a low point 15 degrees below to a high point 15 degrees above level and back to the low point. This carbonation level could be maintained with a flow rate of 400 oz. per hour. Moreover, in the present example, control 44 provided for oscillating of the carbonator five minutes each time sensor 48 signals control 44 to replenish carbonator 12 with water. The particular point of maximum carbonation is, of course, highly dependent upon the volume and structure of the carbonation tank; however, it is believed that the optimum carbonation is achieved in a manner substantially synchronous time of propagation of a wave movement of the water from one end of the tank to the other. It will be apparent to those of skill that many other cycling time approaches could be used depending upon design requirements. In particular, a constant cycling could be employed. The cyclical speed that yields maximum carbonation is, of course, highly dependent upon the volume and structure of the carbonation tank; however, it is believed that the optimum carbonation is achieved wherein the time required to move from a high position to a low one, or vice-versa, is substantially synchronous with the time it takes for a wave propagated by such motion to move from one end of the tank to the other. 
     In addition, the present invention can optionally include the cooling fan 32 for providing a circulation of cooled air from evaporator 34 across carbonating tank 12. In this manner, the carbonation level can be further enhanced. It will also be understood that the carbonation level can be further improved by providing pre-cooling of the water supply to tank 12, such as through the use of pre-cooling tank 42. Various other pre-cooling means can be used, such as a length of heat exchange tube extending in a serpentine fashion through an ice bank. It can be appreciated by those of skill that carbonation system 10 is most advantageously used in combination with a complete beverage dispensing equipment wherein such an ice bank is typically included. 
     As will be understood by those of skill in the art, various modifications can be made to the present invention and still remain within the scope thereof. For example, the point of pivotal attachment of the carbonating tank and the particular dimensions thereof are a matter of design choice.