Refrigeration – Means producing shaped or modified congealed product – With means for working congealing material – e.g. – beater
Reexamination Certificate
1998-05-15
2001-04-24
Tapolcai, William E. (Department: 3744)
Refrigeration
Means producing shaped or modified congealed product
With means for working congealing material, e.g., beater
C062S059000
Reexamination Certificate
active
06220047
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to semi-frozen food product producing machines, including frozen carbonated beverage (FCB) machines, and in particular to the cooling and beverage blending systems thereof and the drive and control systems therefor.
BACKGROUND
FCB making and dispensing machines are known in the art and generally utilize a freezing cylinder for producing a slush beverage therein. An evaporator coil is wrapped around the exterior of the cylinder for cooling the contents thereof. A scraper mechanism extends along the central axis of the cylinder and is rotated to scrape thin iced or frozen layers of the beverage or food product from the internal surface of the cylinder. A carbonator tank is used to produce carbonated water by the combination therein of water and pressurized carbon dioxide gas (CO
2
). The carbonated water and a syrup are then combined in the desired ratio and introduced into a separate blender bottle. The properly ratioed beverage is then delivered from the blender bottle into the freeze cylinder. A problem with this approach concerns the warming of the contents of the carbonator and blender bottle wherein high pressures are required to maintain the desired level of carbonation at such elevated temperatures.
An ongoing problem with FCB machines, and related to the foregoing, is the amount of cooling that is required to make and maintain a beverage in a semi-frozen state. This cooling demand is especially great during times of high use when, as drinks are being dispensed, new ambient temperature water and syrup are continually being added to the cylinder from the blender bottle. A strategy has long been needed to provide for high draw capacity in an FCB machine without resorting to the expedient of requiring ever larger refrigeration compressors and systems with their concomitant increase in machine purchase cost, cost of operation and noise of operation. A further problem with prior art FCB machines concerns their mechanical or design complexity. This complexity, in terms of numbers of parts, adds cost with respect to manufacture and maintenance, and also negatively impacts reliability. Accordingly, it would be very desirable to have an FCB machine that is less expensive and easier to manufacture and maintain.
A further drawback to FCB machines is the fact that the scraper mechanism inherently requires a shaft portion thereof to extend through a cylinder end for connection to a drive motor, thereby requiring a dynamic seal. This requirement stems from the fact that the drive mechanism is exterior of the cylinder and can not come into direct contact with the food product therein. Naturally, such seals are subject to wear and consequent leaking, especially where the beverage contents are under pressure, as is the case for a frozen carbonated beverage. Major service problems with such machines are related to failed or leaking scraper shaft seals. Accordingly, it would be very desirable to be able to eliminate such seals, yet have a scraper drive mechanism that does not create food compatibility/contact problems, and that has sufficient strength to operate the scraper against the considerable resistance it encounters when producing the desired frozen food product.
SUMMARY OF THE INVENTION:
In a preferred embodiment of the present invention, a dual purpose carbonator/blending bottle, “blendonator”, is connected to a source of beverage syrup, a source of potable water and to a source of pressurized carbon dioxide gas. A pair of ratio valves provide for metering the water and syrup, which combined beverage then flows into a serpentine heat exchange coil and then into the blending bottle. Both the blending/carbonating bottle are retained within an ice bank cooled water bath tank. A refrigeration system provides for cooling an evaporator located in the water tank for forming the ice bank thereon. The blending bottle includes an outlet for connecting the interior volume thereof to a freeze cylinder. The freeze cylinder also includes a further evaporator coiled around an exterior perimeter thereof. The freeze cylinder evaporator is connected to and cooled by the same refrigeration system that cools the evaporator in the water bath tank. A scraping mechanism within the cylinder provides for scraping frozen beverage from the inner surface of the cylinder. A control mechanism provides for controlling the refrigeration system and the cooling of both evaporators.
In operation, the dual purpose blending bottle combines the functions of the separate carbonator and blending bottle system found in the prior art. Thus, the improved blender bottle serves both to carbonate the beverage and to retain a volume of a finished amount thereof. As it is located in the water bath tank, the volume of beverage therein is cooled by heat exchange transfer with the ice formed on the ice bank evaporator. A further volume of the beverage is retained in the serpentine coil and also maintained at a suitably cool temperature by heat exchange contact with the cooled water of the water bath. The beverage is therefore pre-cooled to a temperature just above its freezing point before delivery to the freeze cylinder. Thus, far less cooling power is needed to reduce the beverage to a frozen state, as would be the case in prior art FCB machines where the beverage is typically at a much higher ambient temperature just prior to its introduction into the freeze cylinder. Those of skill will understand that the ice bank provides for this extra cooling, which ice bank is formed by operation of the refrigeration system to build ice on the water bath evaporator. In the present invention, this added cooling is attained with a similar or even smaller sized refrigeration system components than would be used in comparable output prior art FCB machines. This enhanced cooling ability is obtained by the strategy of building an ice bank on the water bath evaporator ostensibly during times of non-dispense and/or when the freeze cylinder evaporator is otherwise not being cooled.
A further advantage of the present invention is seen in the method of controlling the operation of the refrigeration system and the cooling of both evaporators thereof. The control system provides for directing refrigerant to either of the evaporators as is most efficient. Thus, if the FCB machine is in a “sleep” mode overnight when no drinks will be dispensed therefrom, the control can direct all the cooling ability if the refrigeration system be utilized to build up the ice bank at that time. Also, as is known in the art, when the beverage in the cylinder has reached its maximum desired viscosity, the cooling of the freeze cylinder evaporator must be stopped. Since a semi-frozen beverage can warm quickly to an unacceptably low viscosity the compressor must then be turned back on. However, and especially where the FCB machine has more than one freeze cylinder, the compressor can be turned on and off very frequently leading to damaging short cycling thereof. However, in the present invention, rather than stop the operation of the compressor, the control herein has an option to continue the operation of the compressor to cool the ice bank evaporator if further ice bank growth is needed or can otherwise be accommodated. Thus, when cylinder cooling is again required, refrigerant can again be directed thereto whereby a short cycling thereof can be avoided. This strategy of being able to alternate cooling between the cylinder evaporators and the ice bank evaporator presents a major advantage for compressor longevity, as most, if not all, short cycling can be avoided.
A further advantage of the present invention concerns the ability of the electronic control system thereof to obtain more efficient cooling of the freeze cylinders. The present invention uses a control strategy that can more accurately maintain a pre-selected temperature differential between the inlet and outlet temperatures of the freeze cylinder evaporators. A control algorithm utilizes a proportional integral differential control approach that safely permi
Shams Hassan
Valabh Rajesh
Vogel James D.
Weber Paul R.
Hakanson Sten Erik
IMI Cornelius Inc.
Tapolcai William E.
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