Multiple barrel frozen product dispenser

Abstract

A frozen product dispenser is characterized by at least two product freeze barrels for receiving product therein and for freezing the product for dispensing, and a refrigeration system for chilling the at least two barrels. The refrigeration system has at least two evaporators for and heat transfer coupled to each barrel, separate and controllable expansion valves each having an outlet coupled to an inlet to an inlet to an associated one of the evaporators, at least two compressors having outlets coupled to inlets to the expansion valves and inlets coupled to outlets from the evaporators, and at least one condenser in fluid circuit between outlets from the compressors and inlets to the expansion valves. The refrigeration system is controllable to selectively operate one or more of the compressors and one or more of the expansion valves in accordance with the cooling requirements of the barrels to provide an improved turndown ratio for improvements in efficiency of operation of the refrigeration system in response to changing cooling load requirements of the product barrels.

Description

[0001] This application claims benefit of provisional patent application Ser. No. 60 / 799,818, filed May 12, 2006.FIELD OF THE INVENTION [0002] The present invention relates to frozen product dispensers, and in particular to a frozen product dispenser having an improved refrigeration system that efficiently handles large variations in cooling load demands of a plurality of frozen product barrels of the dispenser. BACKGROUND OF THE INVENTION [0003] The load requirements of frozen beverage product dispensers are highly variable, since customer demand for beverages can vary from no drinks dispensed per minute to as many as 3 or 4 or more drinks served per minute. This volatile variation in customer demand results in a very broad range of cooling load requirements for a typical frozen product dispenser, such for example as is shown by the chart of FIG. 2. As can be seen, depending upon ambient temperature and during periods when no product is being drawn, the maintenance cooling load of ...

AI Technical Summary

Benefits of technology

[0006] A primary object of the present invention is to provide a frozen product dispenser having an improved refrigeration system that chills, and efficiently handles large variations in cooling load demands of a plurality of, frozen product barrels.

Problems solved by technology

That represents a 12:1 turndown ratio, which the conventional refrigeration system 20 is not well equipped to efficiently handle.

However, for efficient operation the fixed speed compressor 22 requires refrigerant flow at a relatively constant rate, so when refrigerant flows are changed to meet changing cooling load requirements, refrigeration system balance becomes disturbed and saturated evaporator temperatures drop as loads drop and rise as loads rise, yielding poor control over evaporator temperature.

The result is that during periods where the compressor 22 is not reasonably well matched with the cooling load requirements of the product barrels, the refrigeration system will operate less efficiently and use more energy than would otherwise be required.

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