BACKGROUND OF THE INVENTION

[0001] The manufacture of frozen edible products such as sherbets, frozen yogurts, ice cream, and other frozen dairy products typically involves gradual freezing of a prepared mixture of ingredients within a mixing apparatus until a semi-frozen product is formed. Continuous mixing of the mixture while the mixture freezes limits crystal size within a resulting finished product, thereby allowing a manufacturer to control the finished product’ s texture. Following this continuous mixing of the formed semi-frozen product, the product is typically transitioned to a subsequent freezer to complete the freezing process to form the completed frozen edible product.

[0002] Known mixing apparatuses include a generally cylindrical freezing tank, also referred to in the industry as a tube or a cylinder, and a dasher disposed within the freezing tank to accomplish mixing. The dasher is rotated continuously, and has knives that scrape an interior surface of the tank to drive mixture at a radially outer part of the tank inward. The dasher also includes features to pump the mixture present at a radially inner part of the tank outward towards the interior surface of the tank. Such features are commonly a pump tube, also known as a core, which extends parallel to the tank but is eccentric to the dasher’s axis of rotation. In other words, the core is off-center to the axis of the rotation such that as the dasher rotates, the motion of the mixture within the tank is asymmetric within the volume of the tank. The knives and pump tube cooperate to effect continuous agitation of the mixture within most regions of the tank.

[0003] However, this eccentric motion of the mixture within the tank of such existing systems is inefficient and causes excessive wear on the manufacturing system, requiring constant maintenance and large amounts of energy to operate. There is a need in the art for a more reliable and efficient dasher design, which is capable of making products of desirable textures and consistencies, while minimizing the wear and tear and energy demands of current designs.

BRIEF SUMMARY OF THE INVENTION

[0004] In one embodiment, the present disclosure includes a device for manufacturing a frozen edible product, including a cylindrical tank; and a dasher disposed within the cylindrical tank and configured to rotate in a direction of rotation on an axis of rotation, the dasher having: a generally cylindrical frame concentric with the tank and having a plurality of first gaps; deflectors extending from the first gaps, each deflector extending radially inward relative to the axis of rotation and circumferentially in the direction of rotation; and blades extending radially outward from the dasher.

[0005] In another embodiment, the present disclosure includes a device for manufacturing a frozen edible product, including a cylindrical tank and a dasher disposed within the cylindrical tank and configured to rotate in a direction of rotation on an axis of rotation, the dasher having a generally cylindrical frame concentric with the tank and having a plurality of first gaps, and deflectors extending from the first gaps, each deflector extending radially inward relative to the axis of rotation and circumferentially in the direction of rotation. The dasher may also include blades extending radially outward from the dasher. [0006] Further, the deflectors can be arranged in axially extending rows of deflectors and/or the blades can be arranged in axially extending rows of blades. Additionally, the rows of deflectors and rows of blades can be arranged in an alternating pattern around a circumference of the dasher. Moreover, the alternating pattern may be symmetrical such that the dasher has a balanced distribution of mass relative to the axis of rotation. The dasher can also include a plurality of second gaps such that the blades (if present) extend in the direction of rotation at least partially overlapping the second gaps. The dasher of this embodiment may also include a cylindrical core disposed concentrically within the frame, and a cavity can be defined between a radially inner surface of the frame and a radially outer surface of the core generally in the shape of a circular hollow cylinder. As such, the deflectors can extend radially inward into the cavity. If all present, the cylindrical tank, the cylindrical frame, the cylindrical core and the cavity of the dasher may all be arranged concentrically around the axis of rotation.

[0007] In yet another embodiment, the present disclosure includes a dasher assembly for manufacturing a frozen edible product, including a generally cylindrical frame extending along the axis of rotation, the frame including a plurality of first gaps in the frame and a plurality of deflectors, wherein each deflector extends radially inward and circumferentially in the direction of rotation from a respective first gap in the frame into the cavity, a cylindrical core disposed concentrically within the frame, and a cavity defined between a radially inner surface of the frame and a radially outer surface of the core generally in the shape of a circular hollow cylinder. Further, the cylindrical frame and the cylindrical core may have a balanced distribution of mass relative to the axis of rotation along a majority of a length of the frame. The dasher of this embodiment can also include blades extending radially outward from the frame, such that the deflectors are arranged in axially extending rows of deflectors and/or the blades are arranged in axially extending rows of blades. Additionally, the rows of deflectors and rows of blades may be arranged in an alternating pattern around a circumference of the dasher. Further, the frame and the core can have a constant, continuous circumferential shape around the axis and are co-axial with the axis.

[0008] In yet a further embodiment, the present disclosure includes a method for manufacturing a frozen dairy product, including filling a device for manufacturing the frozen dairy product with an amount of dairy product mixture, the device comprising a cylindrical tank and a dasher positioned within the cylindrical tank and configured to rotate in a direction of rotation on an axis of rotation, the dasher comprising a generally cylindrical frame concentric with the tank and having a plurality of first gaps, and deflectors extending from the first gaps, each deflector extending radially inward relative to the axis of rotation and circumferentially in the direction of rotation, and rotating the dasher in the direction of rotation on the axis of rotation. Further, the dasher can also include a plurality of blades and a plurality of second gaps, whereby each blade may extend radially outward from the frame and at least partially overlapping a respective second gap, wherein during the rotating step the blades may direct a mixture into the frame through the second gaps, and the deflectors may direct the mixture out of the frame through the first gaps. Additionally, the device may include a cylindrical core disposed concentrically within the frame, such that a cavity may be defined between a radially inner surface of the frame and a radially outer surface of the core generally in the shape of a circular hollow cylinder, wherein during the rotating step the blades may direct a mixture into the cavity, and the deflectors may direct the mixture out of the cavity.

[0009] This method may further include the step of preparing the dairy product mixture prior to the filling step, wherein the filling step includes introducing the prepared dairy product mixture. Further, an amount of compressed gas may be introduced to the dairy product mixture prior to the filling step, wherein the filling step includes introducing the prepared dairy product mixture and compressed gas simultaneously. Additionally, the dairy product mixture can include at least a dairy component and optionally a flavor component, wherein the filling step may include independently adding to the device the dairy component, the optional flavor component, and compressed gas, wherein the rotating step may include mixing the dairy component, optional flavor component, and compressed gas to create the dairy product mixture. The rotating step of this embodiment may continue until the dairy product mixture is mixed and cooled into a semi-frozen dairy product, and the method may further include the step of moving the semi-frozen dairy product from the device into a freezer to further cool the dairy product and form the frozen dairy product.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a perspective view of a mixing apparatus according to an embodiment of the present disclosure.

[0011] FIG. 2 is a perspective view of a dasher in the mixing apparatus.

[0012] FIG. 3 is a view along section 3-3 of FIG. 2.

[0013] FIG. 4 is a close view of a blade of the dasher.

[0014] FIG. 5 is a cross-sectional view of a dasher according to an embodiment of the present disclosure illustrating a representative fluid flow within the dasher.

DETAILED DESCRIPTION

[0015] FIGS. 1-3 illustrate one embodiment of a mixing apparatus 10, including a cylindrical or generally cylindrical freezing tank 11 extending along an axis X. A radial direction R is defined perpendicular to the axis X. An elongate dasher 12 is disposed concentrically within the tank 11 along the axis X. As tank 11 and dasher 12 are positioned concentrically, the axis X is also an axis of rotation for the dasher 12.

[0016] FIG. 2 illustrates the dasher 12 in greater detail. The dasher 12 has a cylindrical or generally cylindrical frame 14 that extends along the axis X. A drive shaft 18 operatively connected to the frame 14 serves to enable the dasher to be driven by, for example, a motor in a direction of rotation D.

[0017] The frame 14 according to the illustrated embodiment includes circumferentially alternating rows of first gaps 22 and second gaps 26 that extend axially along the frame. According to the illustrated embodiment, the first gaps 22 are entry gaps and the second gaps 26 are exit gaps for agitated mixture. Mixture herein will be used to refer generally to any materials processed by the mixing apparatus 10. Ingredients for a frozen edible product such as ice cream will be described as an exemplary mixture throughout, but the contents of the present disclosure can be advantageously applied to a variety of substances and products, some of which are described below. The mixture may be one or more substances in any state of matter. Mixtures of solids, liquids, and gases are explicitly contemplated. Further, the mixture could be other than ingredients for a food product. Cosmetic and medical products are contemplated, as well as media for heat exchange. Generally speaking, the dasher of the present disclosure can be used with any mixture to make any product where manufacturing of the product may benefit from heat exchange and the introduction of gas into the mixture to result in a desirable texture and consistency. While any mixtures for which the dasher 12 may be beneficial are contemplated, many of the examples provided herein will be directed towards food products, namely frozen dairy products such as ice cream and other frozen confections.

[0018] Additionally, while any gas is envisioned to be used with the system including the dasher, to incorporate the gas into the mixture, typically compressed air, nitrogen or carbon dioxide are used. Further, such gas introduced into the tank is usually pressurized, or compressed, as the contents of the tank are typically under pressure. However, it is envisioned that there may be uses in which the gas need not be compressed into order to be introduced into the tank.

[0019] Knives 30 extend radially outward from the frame 14 and circumferentially in the direction of rotation D to interact with first gaps 22. As illustrated, the knives 30 may at least partially overlap the first gaps 22. Similarly, deflectors 34 extend radially inward from the frame 14 and circumferentially in the direction of rotation D to interact with second gaps 26. As illustrated, the deflectors 34 may at least partially overlap the second gaps 26. The knives 30 and deflectors 34 are arranged in circumferentially alternating rows in the illustrated embodiment, but other embodiments with differing arrangements are contemplated. For example, embodiments wherein the knives 30 and deflectors 34 alternate axially within a row, or wherein both a knife 30 and a deflector 34 extend over a single gap 22 and/or 26 are contemplated.

[0020] According to some embodiments, the deflectors 34 are of a unitary piece with the frame

14. Manufacturing a dasher 12 according to such embodiments may include, for example, producing a cylinder corresponding to the frame 14 and cutting openings in the cylinder, wherein each of the openings provides one of the second gaps 26 and a blank for one of the deflectors 34. Each resulting blank is then pressed or drawn radially inward to produce the deflectors 34 as illustrated. Such a manufacturing method enables the frame 14 and deflectors 34 to be manufactured from a single piece of material (e.g., as a monolithic structure) which may provide various benefits such as increased strength, since the entire structure is a single piece there are no connections between pieces which could flex or cause movement, and reliability, in that the lack of connections between pieces minimizes weak points which could break.

[0021] The relationship of these features relating to this particular embodiment are further illustrated in FIG. 3, which illustrates the dasher 12 and a cylindrical or generally cylindrical core 38 disposed along the axis X concentrically within the frame 14. A cavity 42 is thus defined between a radially inner surface of the frame 14 and a radially outer surface of the core 38 generally or exactly in the shape of a circular hollow cylinder. Stated another way, a radial distance or spacing 46 between the radially inner surface of the frame 14 and the radially outer surface of the core 38 is uniform or generally uniform around the circumference of the dasher 12 along a majority or entirety of a length of the dasher 12. As such, the dasher 12 according to the illustrated embodiment has a balanced distribution of mass relative to the axis X of rotation. According to various embodiments, the dasher 12 had a balanced distribution of mass relative to the axis X along the majority or the entirety of the length of the dasher 12. Similarly, though tank 11 is not shown in this FIG. 3, cavity 42, core 38 and frame 14, all of which being co-axial and concentric (or generally co-axial and concentric) with one another, are also co-axial and concentric (or generally co-axial and concentric) with tank 11.

[0022] According to the illustrated embodiment, the core 38 does not rotate with the dasher 12.

Instead, the core 38 is rotationally fixed relative to the tank 11. The mixing device 10 of the illustrated embodiment therefore has relatively few wear parts and, as a result, is likely to require less maintenance than some known devices. According to some embodiments, the core 38 is used as a channel for a hot or cold medium to allow for heat exchange with contents of the tank 11. In various examples, a cold medium in the core 38 could be used to cool, semi-freeze, or freeze contents of the tank, a hot medium could be used to warm or even roast contents of the tank, or the medium could be a working fluid in a heating or refrigerating cycle. According to some embodiments, the core also provides a displacement within the volume of tank 11 whereby the amount of volume within the tank 11 to be filled with the mixture is decreased by the amount consumed by the core. Such displacement may have certain benefits, such as by limiting the volume of mixture in the tank, the mixture will change temperature more quickly (because of the decreased volume in the tank as well as the increased surface area of the tank and/or core for heat exchange), and further has a lower residence time in the tank 11 to avoid over-mixing. In the example of the manufacture of ice cream, such displacement may have the benefits of limiting the formation of ice crystals due to faster freezing, resulting in a smoother texture and consistency of the ice cream, and limiting the residence time in the tank, which limits buttering due to over-mixing.

[0023] Further, as discussed herein, the ability of the mixing device 10 to generate large amounts of turbulence and mixing forces may be even further increased by the core 38 remaining stationary, which increases friction and shear forces within the medium being mixed as between the rotating frame 14 and the stationary core 38 (and tank 11). Preferably, the core 38 does remain stationary along with the tank 11, such that only the rotating frame 14 is moving. This minimizes moving parts which may further improve the reliability of the system.

[0024] Attachment of one of the knives 30 according to the illustrated embodiment is shown in

FIG. 4. The knife 30 is attached to the frame 14 by a center attachment 58 and two lateral attachments 62. The lateral attachments 62 provide support in the direction of rotation D, that is, to maintain a free edge 70 of knife 30 in a leading position, while the central attachment pivotally fixes the knife 30 to the frame 14. The knife 30 is therefore fixed at an attached edge 66 to a certain circumferential and axial position on the frame 14, but can pivot such that its free edge 70 can move radially toward or away from the frame 14. When the dasher 12 is rotated in a filled tank 11, resistance from the mixture causes the free edge 70 to travel radially outward until it scrapes along an interior surface of the tank 11. Alternatively or additionally, the knives 30 may be biased outwards, away from frame 14, to provide additional force to ensure knives 30 scrape the mixture off of the inner wall of tank 11 to minimize loss of mixture, to provide improved consistency throughout the mixture in the tank 11, and the like. The knives 30 thereby dynamically adjust to the size of the tank 11 and any irregularities in the interior surface of the tank 11 so as to scrape a maximum amount of mixture from the interior surface. As such, the knives 30 are the only parts of the dasher 12 according to the illustrated embodiment that may move relative to the frame 14 during intended operation. While this is beneficial in many aspects for the mixing device 10 during operation, in certain embodiments, the dynamic adjustment of the knives 30 may allow for a simpler retrofitting process where the dasher 12 can be retrofitted into an existing system, which may or may not include an existing tank 11 into which the dasher 12 can be positioned.

[0025] During use, the knives 30 and deflectors 34, and associated first and second gaps 22 and

26, cooperate to effect continuous mixture within the apparatus 10. Continuing with the above embodiment in FIG. 3 for purposes of illustration, the circumferential and radially outward extension of the knives 30 from the frame 14 creates an inward flow 50 of a mixture when the dasher 12 is rotated in the direction of rotation D in a filled tank 11. The inward flow 50 brings mixture from outside the frame 14 into the cavity 42. Similarly, the circumferential and radially inward extension of the deflectors 34 into the cavity 42 creates an outward flow 54 of the mixture when the dasher is rotated in the direction of rotation D in the filled tank 11. As such, rotation of the dasher 12 continuously drives the mixture into and out of the cavity 42, thereby agitating and mixing the mixture.

[0026] A similar flow pattern according to an embodiment with a clockwise direction of rotation

D is depicted as a continuous flow 56 in FIG. 5. As described above with regard to FIG. 3, the knives 30 and deflectors 33 cooperate to drive the continuous flow 56 of the mixture into the cavity 42 through the first gaps 22 and out of the cavity 42 through the second gaps 26. Of course, while rotation is illustrated in a clockwise direction, the dasher could be set up in the reverse and operated instead in a counterclockwise direction. The dasher can thus be configured to run in a clockwise or counterclockwise direction as desired.

[0027] It should be understood that the flow patterns depicted in FIGS. 3 and 5 only represent flow along a single plane or cross-section of the mixing device 10. According to some embodiments, the mixture is fed in at a first end of the tank 11 and exits at a second end of the tank 11. Feeding the mixture generates an axial movement of the mixture from the first end to the second end, in addition to the circumferential/tortuous flow pattern depicted in FIGS. 3 and 5.

[0028] Compared to some known mixing equipment, the dasher 12 described herein provides more thorough and consistent mixing of the mixture. According to certain embodiments, the deflectors 34 are sized relative to a radial dimension of the cavity 42 to reduce or eliminate dead zones and “coring,” meaning caking of mixture on the core 38. The reduction of dead zones is accomplished in part by the greater turbulence generated by the deflectors 34 relative to some known devices. In certain applications, the additional turbulence can provide improved mixture of ingredients. For example, the additional turbulence can improve the efficiency with which gas is mixed into ingredients for ice cream, thereby benefitting production time and texture in the finished product.

[0029] This agitation and mixing can occur in any cycle or manner desired, for example, it can occur in a continuous manner, by constant rotation of dasher 12, or in an intermittent manner, by performing a cycle of starting and stopping the dasher at intermittent intervals. Depending on the type of mixture in the apparatus 10, the type of texture or consistency desired, or other such variables, the apparatus 10 may be operated in any manner desired. Furthermore, the speed (i.e., the revolutions per minute, or rpm) at which the dasher rotates can be adjusted dependent upon similar such variables, and such speed of the dasher can be adjusted prior to initiation of the manufacturing process or on the fly at any time during the manufacturing process. Still further, the dasher 12 may be rotated in the direction opposite to direction D, which may be useful in situations where the dasher may be clogged, for example.

[0030] An exemplary mixture to be mixed and turned into a semi-frozen consistency in the mixing apparatus 10 is a mixture of ingredients for ice cream. An exemplary mixture of ingredients for ice cream includes at least a dairy component and optionally a flavor component. To these ingredients is added an amount of gas, typically compressed air, which causes increased overrun (defined as the amount of gas pushed into the mixture) in the ice cream, which can be particularly useful in manufacturing low fat ice cream products, which include minimal fats and thus a thinner dairy component, to nevertheless develop a creamy and smooth textured product.

[0031] The mixture may be prepared prior to being filled into the tank 11, meaning the dairy component and the optional flavor component would be introduced to the tank 11 simultaneously. Further, an amount of gas, such as compressed air, may be introduced into the mixture prior to the tank 11 being filled with the mixture. The gas and mixture may then be introduced to the tank 11 simultaneously. Alternatively, any or all of the dairy component, the optional flavor component, and the gas may be kept separate and added to the tank 11 independently from the other elements to be added to the tank. Regardless, rotating the dasher 12 after adding the dairy component, the optional flavor component, and the gas to the tank 11 mixes the substances in the tank 11 to create the ice cream product.

[0032] Though the foregoing description generally relates to production of ice cream, the mixing device 10 of the present disclosure is suitable for a variety of applications. The mixing device 10 is suitable for continuous agitation of products as, for example, coffee beans (e.g., roasting, or other processing, of coffee beans or brewing coffee liquor, such as for freeze dried coffee), grains or cereals (e.g., roasting, cracking, or other processing of grains at various production stages), tomato paste, and for processing various products including hand creams, sorbets, and beverages (whether frozen or all-liquid), any of which may benefit from increased turbulence, which in the presence of a gas such as compressed air, can result in a higher overrun. Further, though the foregoing description explains agitating a product while it freezes, the mixing device 10 could instead be used to agitate a product while it is being heated, temperature regulated, roasted, or the like. In another example, the mixing device 10 could be used within a scraped surface heat exchanger. [0033] Furthermore, in other embodiments, rather than a single inflow into and a single outflow out of the mixing device, more than one inflow and/or outflow may be incorporated into the mixing device, and such inflow(s) and outflow(s) may be positioned anywhere along the length of the mixing device 10 desired. Further, the actual opening into the tank volume for any of these inflow(s) and outflow(s) could be anywhere desired, such as on the end surfaces of the mixing device, on the outer cylindrical surface of the tank, or even through the core 38 (e.g., through one more holes in the core, including in some instances a core that is perforated with one or more holes at one location on the length or along at least a portion of the length, or along the entirety or substantially the entirety of the length). Similarly, any of the inflow openings discussed above could be dedicated to one of the mixture or the gas, or any combination thereof.

[0034] Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.