System for freezing ice cream   

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the manufacture of ice cream and, more particularly, to a system for freezing ice cream that uses brine as a freezing medium.

2. Description of the Related Art

Ice cream machines typically include an evaporator situated proximate a container which holds the material being chilled, e.g. an ice cream base or mix, etc. For example, the ice cream base is typically inserted into a freezing chamber or barrel associated with an evaporator and, after some time, is removed from the barrel as solid or semi-solid ice cream. The evaporator removes heat from the freezing chamber as a liquid refrigerant, such as, FREON®, ammonia, R-404a, HP62, or other liquid having a low boiling point, changes to vapor in response to the heat from the ice cream base or mix. Typically, the evaporator quickly becomes partially filled with vapor as the liquid refrigerant boils (i.e., becomes vapor) in the evaporator.

Since most heat transfer occurs when the liquid refrigerant is changed to vapor, the partially filled evaporator is less efficient than a flooded evaporator (an evaporator filled entirely with liquid refrigerant). The partially filled evaporator also tends to unevenly cool the ice cream because the parts of the evaporator, which are filled with vapor, are not able to cool as effectively as the parts of the evaporator filled with liquid.

Further, prior art ice cream machines have the additional disadvantage of not being able to maintain a constant temperature in the evaporator due to the accumulation of vapor. The quality of the ice cream and the efficient manufacture of ice cream are both dependent upon maintaining a constant evaporator temperature (i.e. a constant barrel temperature). If the ice cream is allowed to become too cold, the mix or ice cream base in the evaporator becomes highly viscous and can block the travel of the ice cream through the barrel. Blockage of the barrel in the freezing process is commonly known as “freeze up”.

Maintaining the temperature of the barrel at a constant level is particularly difficult, as ice cream flow rates through the machine vary and change the cooling load on the evaporator. For example, more heat dissipation is required as more ice cream is produced (i.e., the flow rate is increased). Additionally, if the barrel temperature is too low, refrigerant flood-back problems can adversely affect the operation of the compressor. For example, if the refrigerant is not fully evaporated as it reaches the compressor, the liquid refrigerant can damage the compressor. Further, using liquid refrigerants, such as, FREON®, ammonia, R-404a, and HP62 is hazardous.

SUMMARY

A system for producing ice cream, having a brine tank configured to cool a brine solution. The system includes a brine feed inlet line with a first end and a second end, the first end of the brine feed inlet line being coupled to the brine tank. A freezer is provided having a brine conduit and an ice cream mixing tank, the brine conduit being disposed around the ice cream mixing tank such that the brine solution cooled by the brine tank is in thermal contact with the ice cream mixing tank for removing heat from content in the ice cream mixing tank. The second end of the brine feed inlet line is coupled to a first end of the brine conduit for supplying the cooled brine solution to the brine conduit. A brine outlet line comprising a first end and a second end is provided, with the first end coupled to a second end of the brine conduit. A brine accumulator tank connected to the second end of the brine outlet line is also provided. A brine return line having a first end and a second end and in communication with the brine outlet line and the brine tank returns the brine solution from the freezer to the brine tank. A means is provided for measuring a property of the brine solution flowing out of the freezer in order to provide control for an adjustable baffle for regulating flow of the brine solution in the brine conduit in response to the measured property of the brine solution.

In one embodiment, the system has one or more scraper blades disposed in the ice cream mixing tank for mixing the ice cream mix.

In one embodiment, the measured property of the brine solution is one of temperature, density, light reflectivity, or color, and the means for measuring the property comprises one of a temperature sensor or a plurality of light sources and a plurality of light sensors.

In another embodiment, a system for producing ice cream is provided having a brine tank configured to cool a brine solution and a brine feed inlet line having a first end and a second end, with the first end of the brine feed inlet line being coupled to the brine tank. A mixing tank is provided for an ice cream mix. A first trough is coupled to a top surface of the ice cream mixing tank, with the second end of the brine feed inlet line being coupled to the first trough. The system also includes a second trough coupled a bottom surface of the ice cream mixing tank and in fluid communication with the first trough such that brine flows from the first trough around the ice cream mixing tank and into the second trough, and the brine solution that is cooled by the brine tank is in thermal contact with the ice cream mixing tank for removing heat from content in the ice cream mixing tank. A brine outlet line is provided having a first end and a second end, the first end of the brine outlet line being coupled to the second trough. A brine accumulator tank is also provided, with the second end of the brine outlet line coupled to the brine accumulator tank. A brine return line having a first end and a second end and in communication with the brine accumulator tank and the brine tank is provided for returning the brine solution to the brine tank from the brine accumulator tank. A means for measuring a property of the brine solution flowing into the first trough is used, and an adjustable damper is provided to control the flow of the brine solution out of the second trough in response to the measured property of the brine solution.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters refer to the same parts throughout the different views. Also, the drawings are not necessarily drawn to scale.

FIG. 1 is a schematic diagram of a system for producing ice cream, according to one embodiment of the invention.

FIG. 2 is an illustrative diagram of a freezer barrel used for producing ice cream in the system of FIG. 1.

FIG. 3 is a schematic diagram of a system for producing ice cream, according to another embodiment of the invention.

FIG. 4 is an illustrative diagram of a freezer barrel used for producing ice cream in the system of FIG. 3.

FIG. 5 is a schematic diagram of a system for producing ice cream that includes input and output manifolds, according to still another embodiment of the invention.

FIG. 6 is an illustrative diagram of a freezer barrel used for producing ice cream in the system of FIG. 5.

DETAILED DESCRIPTION

Referring to FIG. 1, in one embodiment a schematic diagram of a system 100 for producing ice cream is shown. The system 100 includes a brine tank 102 that is configured to cool a brine solution, a brine feed inlet line 104, and a freezer barrel 106, which includes a brine conduit 108 such as a pipe or cylinder, and an ice cream mixing tank 110. The system 100 further includes a brine outlet line 112, an ice cream line out 114, a pump 134 for the ice cream mix, an ice cream output pump 132, an ice cream mix line 122, a brine accumulator tank 124, a brine return line 126, a first means for measuring a property of the brine solution, such as a temperature sensor 116, and a second means for measuring a property of the brine solution, such as a temperature sensor 118. The system 100 still further includes one or more brine flow rate controls such as adjustable baffles or valves 120a and 120b, which affect the flow of brine through the brine outlet line 112. Cooling coils 128 are disposed inside the brine tank 102. The system further includes a drive mechanism 136 for driving mixing/scraper blades 202 in the ice cream mixing tank 110 as shown in FIG. 2.

The ice cream mix is a mixture of ingredients that are well known in the art for producing ice cream as well as other frozen dessert foods such as sorbet, sherbet, etc. The ingredients may include, by way of non-limiting example, cream, milk, sugar, water, fruit and flavoring.

Referring to FIGS. 1 and 2, in one embodiment the brine tank 102 is filled with a brine solution 130. The brine solution 130 is cooled to a viscous, crystal-laden consistency with a temperature of about −40° C. via cooling coils 128. The viscous brine solution 130 flows, via gravity, into the brine feed inlet line 104 and into the brine cylinder 108. The first temperature sensor 116, which is disposed on the brine cylinder 108 proximate to the brine feed inlet line 104, measures the temperature of the entering brine solution. The temperature value can serve as an indicator to adjust the cooling coils 128 to either increase or decrease the temperature of the brine solution in the tank 102, as is known in the art.

An ice cream mix is pumped, via the ice cream mix pump 134, into the ice cream mix line 122, and then pushed into the ice cream mixing tank 110 at the same end as where the brine solution enters the brine cylinder 108.

Concurrent with the flow of the viscous brine solution 130 through the brine cylinder 108, the ice cream mix is fed through, and mixed in, the ice cream mixing tank 110 via the scraper blades 202. As the ice cream mix flows through the ice cream mixing tank 110, the viscous, crystal laden brine solution 130 in the brine cylinder 108 absorbs heat from the ice cream mix, thus evenly cooling and ultimately freezing the ice cream. Consequently, as the brine solution 130 absorbs the heat from the ice cream mix, the crystals melt and the brine solution 130 thins. The thin brine solution 130 eventually flows out of the brine cylinder 108 via the brine outlet line 112 and into the brine accumulator tank 124 under the force of gravity. The second temperature sensor 118 measures the temperature of the brine solution 130 flowing out of the brine cylinder 108.

The baffles 120a and 120b control the rate of flow of the brine solution 130 out of the brine cylinder 108. Specifically, the baffles 120a and 120b are configured to adjust the flow of the brine solution 130 out of the brine cylinder 108 in response to the property measured by the second means 118 for measuring a property of the brine solution. As mentioned above, in the embodiment shown, the second means for measuring a property of the brine solution is the second temperature sensor 118 and the measured property is the temperature of the brine flowing out of the brine cylinder 108.

As an example, if the temperature of the brine solution 130 exiting the brine cylinder 108 is below about −40° C., then the brine solution 130 is flowing out of the brine cylinder 108 too quickly, and not absorbing as much heat as possible from the ice cream mix. In this case, in response to the temperature from the second temperature sensor 118, the baffles 120a, 120b would decrease the flow of the brine solution 130 out of the brine cylinder 108 so that the viscous, crystal laden brine solution 130 can absorb more heat from the ice cream mix before the brine exists the brine cylinder 108. Likewise, if the temperature of the brine solution 130 that exits the brine cylinder 108 is higher than about −40° C., then the brine solution 130 is exiting too slowly, and absorbing too much heat from the ice cream mix. In this case, in response to the temperature read from the second temperature sensor 118, the baffles 120a, 120b would increase the flow of the brine solution 130 out of the brine cylinder 108 so that the brine solution 130 does not absorb as much heat from the ice cream mix before it exits the brine cylinder 108.

It should be appreciated by those with ordinary skill in the art that rather than, or in addition to, measuring a brine solution parameter, such as the temperature and using that measurement to adjust the flow of the brine solution, a parameter of the ice cream (e.g., temperature, etc.) exiting the freezer can be measured and that value can be used to increase or decrease the speed of the brine solution out of the brine cylinder or to increase or decrease the flow rate of the ice cream mix through the freezer.

In another embodiment, either the flow rate of the brine or the flow rate of ice cream mix, or both, can be varied depending on the temperature of the ice cream mix at the start of the ice cream freezing process to achieve optimal flow rates so the optimal amount of heat is absorbed from the ice cream mix into the brine solution.

As mentioned above, the thin brine solution 130 eventually flows out of the brine cylinder 108 via the brine outlet line 112 and into the brine accumulator tank 124, preferably by way of gravitational force. The thin brine solution 130 that is collected in the brine accumulator tank 124 is pumped back into the brine tank 102 via the brine return line 126. Because the brine solution 130 has thinned from absorbing the heat from the ice cream mix, the brine solution 130 can be pumped back into the brine tank 102 with less resistance and less power than conventional freezing liquids.

The frozen ice cream is eventually pumped out of the ice cream mixing tank 110 into the ice cream line out 114 via the ice cream output pump 132 for further processing (as necessary) and/or for packaging.

Referring to FIGS. 3 and 4, a schematic diagram of another system 300 for producing ice cream is shown. The system 300 includes a brine tank 302 that is configured to cool a brine solution, a brine feed inlet line 304, an ice cream mixing tank 306, a brine outlet line 312, an ice cream line out 314, an ice cream mix pump 334, an ice cream output pump 332, an ice cream mix line 322, a brine accumulator tank 324, a brine return line 326, and a means for measuring a property of the brine solution, such as a temperature sensor 316. The system 300 further includes an upper trough 308 disposed on top of the ice cream freezer barrel 306 and a lower trough 310 disposed on the bottom of the ice cream mixing tank 306. A plurality of dampers 309 are disposed in the lower trough 310. Cooling coils 328 are disposed inside the brine tank 302. The system further includes a drive mechanism 336 for driving mixing/scraper blades 402 in the ice cream mixing tank 306 as shown in FIG. 4.

As in the system of FIGS. 1-2, the brine tank 302 is filled with a brine solution 330 which is then cooled to a viscous, crystal-laden mix with a temperature of about −40° C. via cooling coils 328. The thick brine solution 330 flows, via gravity, into the brine feed inlet line 304 and then into the upper trough 308 disposed on top of the ice cream freezer barrel 306. The temperature sensor 316, which is disposed on the end of the upper trough 308 that is farthest from the brine feed inlet line 304, measures the temperature of the brine viscous solution.

An ice cream mix is fed, via the ice cream mix pump 334, into the ice cream mix line 322, and then pushed into the ice cream mixing tank 306 at the same end that the viscous brine solution enters the upper trough 308. The thick brine solution 330 fills the upper trough 308 and flows down and around the outside of the ice cream mixing tank 306 and into the lower trough 310.

Concurrent with the flow of the thick brine solution 130 flowing from the upper trough 308 to the lower trough 310, the ice cream mix is fed through, and mixed in, the ice cream mixing tank 306 via the scraper blades 402.

As the ice cream mix flows into and through the ice cream mixing tank 306, the viscous, crystal laden brine solution 330 flowing from the upper trough 308 to the lower trough 310 absorbs heat from the ice cream mix, thus evenly cooling and ultimately freezing the ice cream. Consequently, as the brine solution 330 absorbs the heat from the ice cream mix, the crystals melt and the brine solution 330 thins. The thin brine solution 330 eventually flows out of the lower trough 310 via the brine outlet line 312 and into the brine accumulator tank 224 under the force of gravity.

The dampers 309 control the rate of flow of the brine solution 330 out of the lower trough 310. Specifically, the dampers 309 are configured to adjust the flow of the brine solution 330 flowing out of the lower trough 310 in response to the property measured by the property measuring means. As mentioned above, in the embodiment shown the property measuring means is the temperature sensor 316, and the measured property is the temperature of the brine flowing out of the upper trough 308.

As an example, if the temperature of the brine solution 330 that is flowing out of the upper trough 308 is below about −40° C., then the brine solution 330 is exiting the lower trough 310 too quickly, and not absorbing the ideal amount of heat from the ice cream mix. In this case, in response to the temperature read from the temperature sensor 316, the dampers 309 would decrease the flow of the brine solution 330 out of the lower trough 310 so that the thick, crystal laden brine solution 330 will travel more slowly through the trough 310 whereby more heat from the ice cream mix can be absorbed by the brine solution before it is allowed to flow out of the lower trough 310. Likewise, if the temperature of the brine solution 330 exiting the upper trough 308 is higher than about −40° C., then the brine solution 330 is flowing out of the lower trough 310 too slowly and, consequently, absorbing too much heat from the ice cream mix. In this case, in response to the temperature read from the temperature sensor 316, the dampers 309 would increase the flow of the brine solution 330 out of the lower trough 310 so that the brine solution 330 does not absorb as much heat from the ice cream mix before it is allowed to flow out of the lower trough 310.

As with the embodiment shown in FIGS. 1 and 2, either the flow rate of the brine or the flow rate of ice cream mix, or both can be varied depending on the temperature of the ice cream mix at the start of the ice cream freezing process to achieve optimal flow rates so the optimal amount of heat is absorbed from the ice cream mix into the brine solution.

As mentioned above, the thin brine solution 330 eventually flows out of the lower trough 310 via the brine outlet line 312 and into the brine accumulator tank 324 under the force of gravity. The thin brine solution 330 that is collected in the brine accumulator tank 324 is pumped back into the brine tank 302 via the brine return line 326. As mentioned above, because the brine solution 330 has thinned from absorbing the heat from the ice cream mix, the brine solution 330 can be pumped back into the brine tank 302 with less resistance and less power than conventional freezing liquids.

The frozen ice cream is eventually pumped out of the ice cream mixing tank 306 into the ice cream line out 314 via the ice cream output pump 332 for further processing and/or packaging.

In still another embodiment, another way of controlling the flow of the brine around the ice cream mixing tank 306 is accomplished by regulating the volume of brine in the upper trough 308 by including a plate disposed along the entire length of the bottom trough 310 in place of the dampers 309. The plate is hinged at the end farthest from the brine outlet line 312. The pitch of the plate can be changed (i.e., the plate pivots at the hinge) in response to the temperature read by the temperature sensor 316 to restrict or increase the flow of the brine out of the lower trough 310.

Another embodiment of a system 500 for producing ice cream is illustrated in FIGS. 5 and 6. The system 500 includes a brine tank 502 that is configured to cool a brine solution, a brine feed inlet line 504, a brine input manifold 560 with a plurality of ports 564, and a barrel 506, which includes a brine cylinder or conduit 508 and an ice cream mixing tank 510. The system 500 further includes a brine output manifold 562 with a plurality of ports 566, a brine outlet line 526, an ice cream line out 514, an ice cream mix pump 534, an ice cream output pump 532, an ice cream mix line 522, a first means for measuring a property of the brine solution, such as a temperature sensor 516, a second means for measuring a property of the brine solution, such as a temperature sensor 518, and a drive mechanism 536 for driving mixing/scraper blades 568 inside the ice cream mixing tank 510 as shown in FIG. 6. The system 500 still further includes an adjustable baffle or valve 520 for regulating the flow of brine in the brine outlet line 526. Cooling coils 528 are disposed inside the brine tank 502.

Referring to FIGS. 5 and 6, the brine tank 502 is filled with a brine solution 530 which is cooled to a viscous, crystal-laden mix with a temperature of −40° C. via the cooling coils 528. The viscous brine solution 530 then flows, via gravity, into the brine feed inlet line 504 and into the brine input manifold 560. The viscous brine solution 530 then flows through the plurality of ports 564 into the brine cylinder 508. The first temperature sensor 516, which is disposed on the brine feed inlet line 504, measures the temperature of the entering brine solution.

An ice cream mix is pumped, via the ice cream mix pump 534, into the ice cream mix line 522, and then pushed into the ice cream mixing tank 510. Concurrent with the flow of the thick brine solution 530 through the brine cylinder 508, the ice cream mix is pushed through, and mixed in, the ice cream mixing tank 510 via the scraper blades 568.

As the ice cream mix flows through the ice cream mixing tank 510, the thick, crystal laden brine solution 530 in the brine cylinder 508 absorbs heat from the ice cream mix, thus evenly cooling and ultimately freezing the ice cream mix. Consequently, as the brine solution 530 absorbs the heat from the ice cream mix, the brine crystals melt and the brine solution 530 thins.

The thin brine solution 530 eventually flows out of the brine cylinder 508 into the brine output manifold 562 via the plurality of ports 566. The thin brine solution 530 then flows from the brine output manifold 562 into the brine outlet line 526. The second means for measuring a property of the brine solution (e.g., second temperature sensor 518), which is disposed on the brine outlet line 526 proximate to the brine output manifold 562, measures a property (e.g., temperature) of the brine solution 530 flowing out of the brine cylinder 508.

The baffle 520 controls the rate of flow of the brine solution 530 out of the brine cylinder 508. Specifically, the baffle 520 is configured to adjust the flow of the brine solution 530 out of the brine cylinder 508 in response to the property measured by the second means for measuring a property of the brine solution. As mentioned above, in the embodiment shown, the second means for measuring a property of the brine solution is the second temperature sensor 518 and the measured property is the temperature of the brine flowing out of brine cylinder 508.

As an example, if the temperature of the brine solution 530 that is flowing out of the brine cylinder 508 is below −40° C., then the brine solution 530 is flowing out of the brine cylinder 508 too quickly, and not absorbing the optimal amount of heat from the ice cream mix. Thus, the brine flow would be restricted to slow down the flow rate. If the temperature of the brine solution is above about −40° C., the brine flow could be increased.

As with the embodiment shown in FIGS. 1 and 2, either the flow rate of the brine or the flow rate of ice cream mix, or both can be varied depending on the temperature of the ice cream mix at the start of the ice cream freezing process to achieve optimal flow rates so the optimal amount of heat is absorbed from the ice cream mix into the brine solution.

As mentioned above, the thin brine solution 530 eventually flows out of the brine cylinder 508 into the brine outlet manifold 562 and into the brine outlet line 526. The thin brine solution 530 then flows back to the brine tank 502 to be re-cooled.

The frozen ice cream is eventually pumped out of the ice cream mixing tank 510 into the ice cream line out 514 via the ice cream output pump 532 for further processing and/or packaging.

In yet another embodiment, the heat absorption of the brine solution can be measured by the density of the crystals in the brine solution in the brine conduit or cylinder 108 (FIG. 1). In this embodiment, one or more light sensors and light sources are disposed inside the brine cylinder 108 along the flow path of the brine solution from the brine feed inlet line 104 to the brine outlet line 112. The light from the light sources is reflected by the crystals in the brine solution. Based on the amount of light reflected by the crystals in the brine solution, the density of crystals in the brine solution can be determined. Further, once the density of the crystals in the brine solution is known, the heat absorption of the brine solution can be determined. Moreover, the baffles 120a and 120b are configured to adjust the flow of the brine solution 130 out of the brine cylinder 108 in response to the determined density of crystals in the brine solution.

In other embodiments, the measured property of the brine solution can be color, which is an indication of density. Further, the means for measuring a property of the brine solution can include a means for detecting the color of the brine solution.

The brine solution can be any composition suitable for freezing an item, such as any of the brine solutions disclosed in U.S. Pat. Nos. 4,601,909; 4,654,217; 4,657,768; 4,689,963; 4,743,343; 4,840,034; 4,840,035; 5,001,047; and 6,248,381.

Preferably, the brine solution comprises at least about 0.005% by weight of cruciferous oil. More preferably, about 0.005% to 0.018% by weight of cruciferous oil such as rapeseed oil may be used. Alternatively, the amount of cruciferous oil may be selected such that a maximum amount of the oil is dissolved in the brine.

The brine solution preferably comprises propylene glycol and water. It is also preferable that the brine composition contains calcium chloride. The water used in the composition is preferably deionized before being added into the brine composition.

In accordance with one embodiment of the present invention, the brine composition in a desired balance comprises about 0.01% by weight of rapeseed oil, about 43.18% by weight of water, about 44.06% by weight of propylene glycol, and about 12.75% by weight of calcium chloride.

In accordance with one embodiment of the present invention, the brine may be cooled to a predetermined temperature of below about −20° C., preferably −30° C. to about −43° C., and more preferably about −38° C. to −40° C.

Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps, which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.