The present invention relates to ice cream and more particularly to an apparatus and method for cryogenically manufacturing ice cream.
Conventional ice cream has existed for many years in many embodiments. However, manufacturing ice cream often requires extensive time in complex rotary barrel and hardening freezers. These devices can require expensive and complicated equipment to operate and maintain, such as compressors, evaporators, motors, condensers, and other equipment.
Also, such rotary mechanisms tend to freeze ice cream slowly, and from the outside in, so that large ice crystals are formed therein. If ice crystals formed during the freezing process are too large, the taste and mouthfeel of the ice cream can be watery and diluted. Consequently, a method and apparatus for using cryogenics to freeze ice cream from the inside out is desired.
This invention has as its primary objective a method and apparatus for cryogenically freezing ice cream that does not require or greatly reduces the requirement for the equipment and complexity typically associated with a rotary barrel style ice cream freezer and hardening chamber or hardener, and that freezes from the outside in rather than from the inside out. A further objective of the present invention is to achieve the freezing process more quickly and save on electricity.
These and other objects and advantages of the invention will become readily apparent as the following description is read in conjunction with the accompanying drawings and claims.
Before explaining the disclosed embodiment of the present invention in detail it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown, since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.
A system 100 for cryogenically manufacturing ice cream is shown in
Multiple separate production systems 100 such as that shown in
The process of making of ice cream starts with liquid ingredients, including dairy products, being delivered to a mix tank 104 and blended therein. The blended liquids are conveyed to a rotary barrel freezer 108 where mixing continues and the mixed ingredients are chilled. Unlike the barrel freezers of the prior art, this chilling is achieved cryogenically through a variety of means, including a supply 180 for blowing or sputtering cryogenic air through the ice cream mixture while it is whipped or agitated. Within the present invention, the air from the supply 180 can include a cryogenic gas such as Liquid Nitrogen (LN2) with a nitrogen percentage such as but not limited to 80%. LN2 is advantageous because it is liquid at atmosphere pressure at temperatures below −320° F. (−195.8° C.), and is completely sanitary and can be applied directly to food products. However, other cryogenic gases could also be used, but potentially would require modifications to the system 100 of the present invention.
The forced movement of such exceptionally cold air assists in freezing the ice cream with smaller ice crystals that are more effectively dispersed. This in turn results in a less watery, less diluted frozen product which is tastier and has a smoother texture and mouthfeel.
Within all embodiments of the present invention, the LN2 can come from bulk tanks or supplys 180a-d which must occasionally be purged or let off some discharge, particularly during long periods of disuse. Because the LN2 stored therein is so exceptionally cold, atmospheric heat from normal room temperature storage can lead to a buildup of pressure within the supplys 180a-d. Consequently, channeling the excess LN2 could lead to additional cost savings because the expectation is that in any LN2 storage, some discharge will inevitably occur. It is advantageous to channel that inevitable LN2 discharge into some productive use.
Within the barrel freezer 108, the mixed ingredients are chilled to a temperature of 0°-17° F., although the present invention should not be considered as limited to this temperature only. Consequently, all equipment shown in the embodiments of
Additionally, existing prior art implementations tended to keep the semi-soft ice cream mix at 20° F. until it reaches the hardening chamber. This was partly so less ruggedized and lower horsepower equipment could be used, but also because the ice cream mix is somewhat easier to handle at this temperature, having a lower viscosity. As shown in
It is true that the semi-solid ice cream still must be pumpable and manageable before going into the container 172. However, the aerated and pre-hardened ice cream of the present invention needn't be completely hardened before going into the container 172, although it will have a high viscosity and thus a high resistance to movement, likely higher than in mechanisms of the prior art. Accordingly, the present invention will require equipment capable of generating high torque and thus will probably need significant horsepower and possibly a transmission or some type of torque conversion means.
For example, using N2 gas and LN2 within the system 100 of the present invention as described herein, the ice cream mix 0-17° F. could still move, but would be more resistant to movement. Despite this, it is still an advantage that the ice cream mix at 0-17° F. is sufficiently cold to go directly into the inventory freezer 156, so that no hardening chamber 144 is necessary.
The rotary barrel freezer 108 is shown in more detail in
Within the present invention, it is also contemplated that the freezing barrel 108 may not rotate at all. The complexity and rigor of hooking extra tubes, nozzles, and measurement equipment onto a rotating barrel 108 may not be necessary. It may be possible instead for the barrel 108 to remain stationary, since the auger 188 is providing the left-right movement, and also because the actual freezing is occurring more through the LN2 nozzles 505 and less through contact with the side-surfaces of the barrel 108. In either case, the auger 188 or some other type of propulsion or scraping means moves the higher-viscosity frozen material from left to right, eventually being outputted through the output valves 506.
A comparison of
Within the system 100 of the present invention, it is desired to have a large proportion of LN2 make contact with the liquid ice cream mix. This is because an overabundance of N2 gas bubbles could expand within the ice cream and cause huge overrun (undesired increase in volume and reduction in density), resulting in as much as 300% or 400% overrun. The resulting product would almost be like a whipped cream, fluffy and low-density, which is an undesired characteristic.
Thus, it is desired for at least some of the LN2 to stay liquid LN2 as long as possible, and not turn to gas N2. The exact proportion of gas/liquid can vary. LN2 can stay liquid if the surrounding metal of the nozzles and pipes are pre-cooled, and thus won't turn into gas until it directly hits the ice cream mix. In this way the desired amount of whipping or aerating or pre-aerating can be achieved, and is accomplished using both LN2 and N2, and not solely gas N2.
There is another way to reduce overrun, by controlling pressure within the freezing barrel 108. It is possible to entirely fill the freezing barrel 108 with liquid ice cream mix, and let off excess gas or increase gas, yet don't let out any of the high viscosity semi-soft ice cream. This way it is not possible for the ice cream product to expand in volume. One change in such an implementation is that the freezing barrel 108 may no longer rotate. In prior art barrel freezers, the ice cream was created by contact with the sides of the ever-rotating barrel, and then scraped from the sides as a semi-solid, and then moved from left to right within the barrel. Finally, the overrun problem could be overcome by using a combination of gas N2 and liquid LN2.
It is also important to manage the amount of refrigerant going into the barrel 108. In other words, it is important to regulate the volume of LN2 to match the volume of ice cream mix going thru the barrel 108. Too much LN2 and/or gas N2 means too much overrun, too little density, too much whipping and aeration. One way to do this is to measure and regulate the volume of gas coming out of the LN2 bulk tanks 180, but it is also possible to measure volume/pressure of ice cream mix. The second could be used as a check on the first, or vice-versa. Between the two measurement systems, it is possible to obtain an accurate reading of both volumes, and therefor manage the overrun to keep it within the desired guidelines, or to eliminate overrun entirely.
Using the cryogenic system 100 of the present invention, the improvement in quality of the resulting ice cream product will be noticeable. Also, eliminating the hardening chamber 144 will also generate significant savings in both time, package handling, equipment, electricity, and other measurable quantities too numerous to mention.
Returning to
It will be further understood that flavor dispensers 116 are preferably capable of selectively dispensing one or more flavorings depending upon the desired end flavor mixture. For example, a dispenser 116 may hold cherry, strawberry, or chocolate flavoring ingredients, whether solid, cryogenically frozen, semi-solid, or liquid, in individual compartments or chambers within the dispenser 116. Because some of these flavorings by themselves may not be suited to cryogenic liquids and gases, the process controlling mechanism 124 can direct a flavor dispenser 116 to selectively dispense one or more of these flavoring ingredients either before or after the ice cream mix has been pre-hardened.
The package fillers 118 of the present invention are customized to be specific to a particular package. Thus, if filling half gallon rectangular cardboard “brick” containers, the package filler would be specifically designed to completely fill and close the one half gallon brick container. Alternatively, if filling half gallon or quart round tubs, a different package filler designed for such a package would be used.
In
As shown in
After the container 172 is filled with ice cream mix, a lid must be placed upon it or its flaps must be closed. These functions are performed at the packager 132 where an optional shrink wrap may also be applied. Shrink wrapping can be done at this point to ease handling of the finished product and improve efficiency of the overall package-handling operation. Adding shrink wrap prior to hardening can also increase the resulting package's resistance to changes in temperature. In any case, whether shrink-wrapped or not, the packaged ice cream products are then conveyed to a hardener 144 where they will reside for varying times while the ice cream contained in the container is chilled and hardened. The exact durations of time spent in the hardening chamber 144 can be arrived at through experimentation, partially depending on the particular mix of ingredients.
One type of hardener 144 is a roller bed hardener, although the present invention should not be considered as limited exclusively thereto. Roller bed hardeners have roller conveyors inside of insulated rooms wherein chilled air is circulated to remove heat from the ice cream and chill the product down to a low temperature, typically 0° F. (−18° C.) or less. To accommodate these rollers and also have convenient access to the products contained therein, a very large room is required. Keeping such a room sufficiently cold can incur substantial energy costs.
A second type of hardener 144 is known as a contact plate freezer. Contact plate freezers work best with rectangular or cubic products having one or more flat surfaces such as half gallon cardboard ice cream containers, but don't work quite as well with round tubs. The containers are packed closely together and very cold aluminum plates are placed on the top and bottom of the containers chilling them by direct contact with the cold metal. The metal plates can be kept cold using cryogenic means such as direct application of LN2 to the plates, or can have electrical or electronic elements which cause the metal to consistently sustain low temperatures. The times necessary to reach appropriate hardening temperature vary. The hardeners 144 described above can be large and expensive to install and are thus most cost-effective with very large production runs. However, the size, complexities, and energy consumption of the hardener 144 can be reduced or even eliminated by using the pre-hardening techniques of the system 100 of the present invention.
Following the hardening process to completion, in all embodiments of the present invention the finished ice cream product is conveyed to an inventory freezer 156 prior to sale and shipping. In prior art systems such as that shown in
As shown in
As stated, the filler 118 acts to completely fill the containers 172 in a quick automated manner. However,
In the embodiment where the nozzles 181 are in direct contact with the ice cream mix inside the container 172, the nozzles can be operated at a pressure and velocity sufficiently low that the ice cream mix is not spattered or splashed outside the container. A diffusion mechanism (not shown) such as a bayonet fitting or other type of pressure regulator can be attached to the surface of the nozzle 181 so that unwanted gusts of LN2 and the resultant spattering of ice cream do not occur, and instead the flow of LN2 is carefully regulated.
In an alternative embodiment, the nozzles 181 and the blown air therefrom can cause a limited, controlled amount of tunneling or holes into the actual finished ice cream product. The supercooled product could have a tunneled, swiss cheese type of look and finish, although taste and texture would not be affected. Because ice cream is sold by weight, a slightly larger package can be used to accommodate the product's increased volume which results from the tunnels and or holes caused by the nozzles 181, yet still maintain a chosen specific product weight per unit. Thus, a customer would not be paying a premium for all the extra air in their package. In such an embodiment, the package filler 118 described earlier would be altered so as to not act to remove air voids in the container 172.
The nozzles 181 can also act as temperature probes, or have adjoining temperature probes attached therewith, so as to feed back information to the centralized controlling mechanism 124 which can make decisions about sufficiency of frozenness. As stated, the controlling mechanism 124 can be located near the hardening chamber 144, but also can be located off-site and communicate wirelessly with a relay mechanism (not shown) in direct mechanical and electrical contact with the nozzles/probes 181 or other devices within the system 100. Again, all such computer and communication equipment must be sufficiently ruggedized to withstand these extremely low temperatures.
In such an environment, the hardening time required of any ice cream product is greatly reduced, so that the hardener 144 may not be necessary at all (hence the dashed lines in
Additionally, within the configuration shown in
If solid ingredients are used, they may be cryogenically frozen into chunks, pieces, particles, or beads prior to being incorporated inside the ice cream at ingredient feed 160. Thus, the ice cream product can be frozen from the inside out, as well as from the outside in using the techniques and equipment described herein. A mechanism for cryogenically freezing ice cream into ultra-cold beads is shown in U.S. Pat. No. 5,126,156, the contents of which are hereby incorporated by reference.
Referring now to
It is an advantage of the embodiment shown in
The various aspects of the present invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described herein. It is anticipated that various changes may be made in the arrangement and operation of the system of the present invention without departing from the spirit and scope of the invention, as defined by the following claims.
This application claims priority to U.S. Provisional Patent Application No. 60/505,641, which was filed on Sep. 24, 2003.
Number | Date | Country | |
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60505641 | Sep 2003 | US |