Refrigeration – Means producing shaped or modified congealed product – With means for working congealing material – e.g. – beater
Reexamination Certificate
2001-11-02
2003-04-29
Tapolcai, William E. (Department: 3744)
Refrigeration
Means producing shaped or modified congealed product
With means for working congealing material, e.g., beater
C222S146600, C251S335200
Reexamination Certificate
active
06553779
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 for improving the quality, consistency, and efficiency of operation while improving product yields and ease in cleaning of machinery utilized in the manufacture and dispensing of semi-frozen, frozen food products or beverages.
Dispensing Door Construction
An important structure in a softserve product refrigeration machine is the dispensing door construction, which usually also carries with it the product dispensing valve mechanism utilized for removing product from the freezing cylinder (evaporator). An ideal door would be one which minimizes condensation so that it does not have to be continuously attended to by an attendant; one that provides an excellent seal for the freezing cylinder when the door is closed; is designed so that the seal between the door and the freezing cylinder does not create an obstruction which catches the softserve product, or inhibits proper drainage of product/cleaning and/or sanitizing fluids therefrom when the freezing cylinder is being cleaned. Many designs have utilized a flat gasket between the door and freezer, such as the Clifford patent (U.S. Pat. No. 3,050,960, issued on Aug. 28, 1962), which construction requires a high pressure being exerted to effect a proper seal. Other designs have utilized an O-ring captured inside the freezing cylinder and projecting or protruding from the interior surface of the freezing cylinder. While an O-ring eliminates the need for high forces, it obstructs the proper drainage of product from the freezing cylinder. In essence, the O-ring design requires that the product exit port be raised above the bottom edge of the freezing cylinder by an amount equal to the width of the O-ring seal. In this manner, it is difficult to provide proper drainage of product or cleaning and/or sanitizing fluids when cleaning both the door and the freezing cylinder. It should be mentioned that U.S. Pat. No. 2,916,044, issued on Dec. 8, 1959, does illustrate a cover and serving valve for freezers utilizing an insulation which is primarily for inhibiting condensation due to the capturing of the retard (or baffle) in the cover.
Dispensing Valve Mechanism
Another important aspect of a properly designed softserve product refrigeration machine is the dispensing valve mechanism. While valve mechanisms have varied, it is absolutely essential that the mechanism be easy to clean. That is, the valve mechanism must have no physical internals which allow for food product retention such that it can be easily cleaned by flushing with sanitizers. Valve designs which use a plunger with O-rings have small crevices between the moving parts where food product becomes lodged and is difficult to remove in the cleaning process. These designs, moreover, allow leakage of food product past the O-ring and this leakage of food product makes it incapable of effective cleaning in a clean-in-place process. Moreover, this kind of design must be lubricated, which usually requires disassembly. Another desirable feature of an ideal dispensing valve is that all product in the dispensing spout should be forced from the valve leaving no residual product to later melt and dip.
In order that the reader may better understand the nuances of the softserve refrigeration and freezing process, the following material is tendered, and directed towards various ones 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 novel softserve 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:
(
W
L
W
P
-
1
)
×
100
W
L
=Weight of volume (test) of raw liquid mix
W
P
=Weight of an equal volume of product (including air)
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 i
Boyer George
Meserole Michael
Mrugala Ronald J.
Sonnenschein Nath & Rosenthal
Specialty Equipment Companies, Inc.
Tapolcai William E.
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