Refrigeration – Processes – Congealing flowable material – e.g. – ice making
Reexamination Certificate
2002-02-19
2002-12-10
Tapolcai, William E. (Department: 3744)
Refrigeration
Processes
Congealing flowable material, e.g., ice making
C062S303000, C062S342000
Reexamination Certificate
active
06490872
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to improvements in semi-frozen, frozen food product or beverage refrigeration machines, and more specifically, relates to improved structures and methods for improving the quality, consistency, and efficiency of operation while improving product yields and ease in cleaning of machinery utilized in the manufacturer and dispensing of semi-frozen, frozen food products or beverages.
Clean-in-Place (Cleaning of the Machine)
Conventionally, softserve machines require daily cleaning and/or sanitizing to insure that undesired bacteria and the like are eliminated. Because of the intricate parts of such machines, traditionally the machines must be disassembled and each part that contacts food thoroughly decontaminated and cleaned. The machine is then reassembled. This process can require trained personnel and personal attention several hours a day. Moreover, this procedure usually occurs after normal operation hours requiring overtime or additional personnel. What has long been desired, is a machine design which allows for “Clean-in-place” and employs a method of cleaning that is reliable and safe, is quick and which does not require disassembly and reassembly of the machine while insuring cleanliness of the machine. That is accomplished by a softserve product refrigeration machine designed in accordance with the present invention. As will be seen, special machine construction allows for complete “Clean In Place” operation without disassembly of the machine for cleaning.
In order that the reader may better understand the nuances of the softserve refrigeration and freezing process, it is believed essential that an understanding of the entire machine operation must be understood. To that end, the following material is tendered, and directed towards various features of the copending applications set forth above.
Increasing Refrigeration Cycle Efficiency
Normally, semi-frozen, frozen confection food product or beverage (hereinafter “softserve product”) is drawn from a freezing cylinder or chamber (evaporator) at intermittent times. However, the product must be in a proper state for serving when it is needed. Conventionally, to maintain product temperature and/or viscosity at an ideal state, the main refrigeration system is required to run quite frequently. Moreover, dependent upon the draw of the softserve product, additional quantities of product mix, usually kept at a refrigeration temperature below 41 degrees Fahrenheit to prevent spoilage, requires an increase draw of such mix, proper aeration or “overrun”, which of course, creates further cycling of the main refrigeration system.
Numerous attempts have been made to reduce this refrigeration system recycling so as to increase the efficiency of the system. For example, in U.S. Pat. No. 5,386,709 (issued on Feb. 7, 1995), methods and apparatus are disclosed for incorporating thermal storage and other low temperature reservoirs with a secondary or retrofitable refrigerant circuit to increase the thermal operating capacity and efficiency by subcooling refrigerant condensate with subcoolers. However, auxiliary power equipment is required, once again lowering the overall system efficiency making it undesirable for softserve product dispensing refrigeration machines. In other systems, such as in U.S. Pat. No. 4,643,583 (issued on Feb. 17, 1987), a eutectic liquid is introduced into a space intermediate an inner metal vessel and an outer case. The purpose of the provision of a eutectic liquid is purportedly to maintain the vessel at a nearly constant temperature so as to ensure whisking (or commonly referred to as scraping) of the ice cream mixture within the cold storage container. But this system also requires a second refrigeration system in order to maintain the container at the whisking temperature.
During the transition from active freezing of the product to the Idle State of the refrigeration system, the temperature of the Evaporator must be raised to prevent “Sticking” of the scraping or beater blades upon subsequent restarts. To accomplish this, the evaporation temperature should be preferably raised to within a few degrees of the product temperature. In this manner, “sticking” of the scrapers on the next restart does not occur. This is accomplished in the described apparatus by a novel method and means without necessitating a second refrigeration system.
Overrun
It is well-known that it is essential for consistency of softserve product that an amount of gaseous matter such as air should be incorporated into the liquid ice cream mix at the time of freezing. “Overrun”, which is defined as a percentage, may be determined in a number of ways, one such way is:
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Overrun is accomplished either with a feed tube and air orifice in a gravity style freezer, such as illustrated in U.S. Pat. No. 5,706,720 (issued on Jan. 13, 1998) or a pump in a pressurized freezer. The feed tube method does not provide accurate control of overrun because the liquid fill rate is dependent upon the mix level in the hopper and the air flow rate is affected by “barrel” pressure. Thus, when product is being dispensed from the freezer, a pressure drop is sensed in the barrel (the feed tube or conduit which supplies applying mix and air to the freezer unit) changing the overrun percentage. Thus, with this type of apparatus, at best, a limited overrun range is provided and it is difficult to control the percentage (%) of overrun.
In a pressurized freezer, a pump is employed which provides somewhat improved accuracy allowing for a greater range of overrun but requires physical component change to vary the overrun settings. Moreover, the pump also adds a degree of complexity to the freezer operation because of the number of components that must be cleaned, lubricated and reassembled. Once more, the control of overrun by the pump is effected by the draw rate of the softserve product. Since the pump is a positive displacement device for the liquid portion and a pressure sensitive device for the air portion, while the liquid mix flow rate is not affected by changes in barrel pressure, which can vary with the draw rate, the air flow rate, being pressure sensitive, will vary as the barrel pressure changes. Such a system is shown in U.S. Pat. No. 4,457,876 (issued on Jul. 3, 1984). Once again, it would be desirable to provide a system which would allow control of overrun by an accurate setting of the overrun. Moreover, the system provided should be easily cleaned, preferably without removing or disassembling the system such as necessary with a pump system.
Beater or Scraping Blades
Once the mix and proper air mixture has been fed into the freezer, it is vital that the mix be moved or beaten so that a continuous folding or blending of the nearly frozen mixture occurs in the freezing cylinder, and that the material as it freezes in the freezing cylinder is whisked or scraped off and dropped back into the mix for further blending and movement within the cylinder. Most beater designs have involved a framework of stainless steel bars and castings. In fabrication, these designs required a large amount of welding or brazing to complete the manufacture. Moreover, welding oftentimes proves to be less sanitary than desired and the brazing operation also lacked compatibility with highly acidic mixes. While there have been many designs recommended for beater construction (see Re. 32,159 of May 27, 1986, which utilizes insertable blades), and the design illustrated in U.S. Pat. No. 512,002 (issued on Jan. 2, 1894), all of these designs require massive constructions and are difficult to fabricate in order to arrive at a strength sufficient to be ab
Beck Norman L.
Boyer George C.
Duncan David C.
Mrugala Ronald J.
Sonnenschein Nath & Rosenthal
Specialty Equipment Companies, Inc.
Tapolcai William E.
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