High pressure processing (also “HPP”) is used to reduce the microbial load on foods, beverages, cosmetics, pharmaceuticals and other products without significantly altering the characteristics of the processed product. The pressure level required for HPP to be successful is typically at least 4,000 bar.
Traditional equipment for treatment of beverages and other liquids as well as pumpable foods and other products by HPP is based on the processing of the products after having been placed as individual units into flexible packaging, for example, bottles, cartons, or pouches. The individual units are grouped or consolidated within a larger reusable load basket which is sized and shaped to fit into a wire wound high pressure vessel (also referred to as “wire wound vessel” or “high pressure vessel”).
Such high pressure vessel is filled with water which serves as the pressurizing medium. Once the wire wound vessel has been filled and closed, high capacity pumps introduce additional water into the pressure vessel so that the pressure therein is increased from about 4,000 to 10,000 bar. This pressure is maintained for a sufficient length of time, from a few seconds to several minutes, to reduce the microbial load on the products being treated. The particular pressure level and the time duration of such pressure are specific to the product being processed.
Once the desired level of inactivation of the microorganisms has been achieved, the pressure in the vessel is released and the load basket is removed from therein so that the individual packages can be extracted. The processed product has, after being exposed to high pressure and hold time, been pasteurized, the microbial load has been reduced, and an extended shelf life has been achieved.
HPP has also been used in the “bulk” processing of the product, especially pumpable products. The pumpable products are placed in a large flexible bag or bladder type container located inside the pressure vessel thereby to occupy a significant proportion of the useful volume within the pressure vessel. The bladder is then pressurized by the pressure media in much the same way as if a load basket were used.
During an HPP cycle, the processing media, as well as the product being processed, are subject to an adiabatic temperature rise by virtue of the pressure being applied thereto. This increase in temperature is typically 3° C. per 1,000 bar. Thus, at an operating pressure of 6,000 bar, the temperature increase can be approximately 18° C.
Different materials exhibit different adiabatic properties so that with increase in pressure, the temperature increase may vary. This can create a layered or stratified temperature distribution along the height or depth of the pressure media or product processed in an HPP pressure vessel. This thermal distribution in the pressure vessel can result in a significant temperature variation range in the product being processed. Applicant has identified layering effects that under certain circumstances may have a negative effect on the end result of the final product being processed in an HPP pressure vessel. The lower portion of the contained pressure media and product may be significantly colder than the upper portion of the contained pressure media and product. In some tests conducted by applicant, the upper 60% of the pressurized volume was more temperature homogenized than the lower 40% of the pressurized volume.
Applicant’s tests also have indicated that the stratification or layering of the temperature of the processing media or pumpable product during HPP is due to changes in the density of the processing medium or pumpable product caused by the pressure applied therein. As a result, the colder processing media or pumpable product tends to sink while the warmer processing media or pumpable product tends to rise.
The foregoing temperature stratification or layering may not be of significant concern or an important factor in a normal or standard HPP process. However, if HPP is carried out at a specific temperature, especially within a narrow temperature range, for example, when processing dairy products to achieve a desired pasteurization level, then the temperature stratification of the processing medium as well as the dairy product can be of vital significance. The present disclosure seeks to address this stratification of the temperature of the processing medium and/or product being processed in an HPP system.
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
In the following description and in the accompanying drawings, corresponding systems, assemblies, apparatus and units may be identified by the same part number, but with an alpha suffix. The descriptions of the parts/components of such systems assemblies, apparatus, and units that are the same or similar are not repeated so as to avoid redundancy in the present application.
The description set forth below in connection with the appended drawings, where like numerals reference like elements, is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Similarly, any steps described herein may be interchangeable with other steps, or combinations of steps, in order to achieve the same or substantially similar result.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of exemplary embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that many embodiments of the present disclosure may be practiced without some or all of the specific details. In some instances, well known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure. Further, it will be appreciated that embodiments of the present disclosure may employ any combination of features described herein.
The present application may include references to “directions,” such as “forward,” “rearward,” “front,” “back,” “ahead,” “behind,” “upward,” “downward,” “above,” “below,” “horizontal,” “vertical,” “top,” “bottom,” “right hand,” “left hand,” “in,” “out,” “extended,” “advanced,” “retracted,” “proximal,” and “distal.” These references and other similar references in the present application are only to assist in helping describe and understand the present disclosure and are not intended to limit the present invention to these directions.
The present application may include modifiers such as the words “generally,” “approximately,” “about,” or “substantially.” These terms are meant to serve as modifiers to indicate that the “dimension,” “shape,” “temperature,” “time,” or other physical parameter in question need not be exact, but may vary as long as the function that is required to be performed can be carried out. For example, in the phrase “generally circular in shape,” the shape need not be exactly circular as long as the required function of the structure in question can be carried out.
The present application refers to “processing medium” used in the HPP system for applying high pressure to the product being processed. Such processing medium is also referred to in the application as processing fluid or processing water as well as referred to as pressurized/pressure medium, pressurized/pressure fluid or pressurized water. All of these terms are to be used interchangeably.
In addition, the present application refers to the pressure vessel of an HPP apparatus. Such pressure vessel is also referred to as wire wound vessel or simply vessel. These terms are to be considered as synonymous.
Also, in the present application the term “container” shall generically refer to both open type load baskets and closed containers. In this specification the term “load basket” will be used to refer to an open type container and the term “container” will be used to refer to a closed container, so as to help avoid confusion between these types of containers.
Further, the present application refers to a “product” or “products” that are subjected to or treated by HPP using the containers of the present disclosure. Such product(s) may include all manner of foods, including pumpable foods or beverages, as well as non-food products, such as cosmetics, pharmaceuticals, and organic materials and substances, wherein the control of pathogens is desirable.
As shown in
With continued reference to
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A plurality of fluid passage holes 44 may be provided through the sidewall 28 of the cylindrical body 22 to allow the pressure-transmitting medium of the high pressure processing chamber to fill the interior 30 with pressure media before the pressure increase initiates. In addition, or alternatively, the fluid passage holes 44 may allow the pressure-transmitting fluid to drain out of the interior volume 30 during and/or after processing. While the fluid passage holes 44 are shown as being positioned in a bottom portion of the cylindrical body 22, it will be appreciated that the fluid passage holes 44 may be positioned at any suitable location, and in any suitable quantity.
In addition, or alternatively, auxiliary fluid passage holes 46 may be provided in at least one of the first or second ends 24, 26 of the cylindrical body 22.
Further as shown in
The features of load basket 20 described above may be employed in the load baskets described below and shown in
The present disclosure below provides various embodiments of both load basket and bulk containers designed to address the temperature stratification or layering phenomena that occurs in a typical HPP application. In this regard, load baskets and bulk containers are provided wherein the typical bottom portion of the load basket or container is truncated or filled in so as to eliminate a bottom well section of the basket/container. The cooler, heavier density processing medium or pumpable product tend to collect in the bottom well and thus not mix with the warmer processing medium or pumpable product fluid located above. Also, the product being processed is kept away from the lower portion of the pressure vessel where the colder processing medium tends to collect.
Also, it is desirable that the load basket and/or bulk container retain its orientation in a processing chamber so that the removed or modified lower section of the load basket/container remains in correct orientation. Typically, a processing chamber for receiving the load basket/bulk container is cylindrical in cross section, and does not provide any structure or other means for orienting the load basket or bulk container in any particular rotational position relative to its longitudinal axis.
With the elimination of the concave lower portion of the body portion 64, there is less likelihood that the colder and denser processing fluid circulating through the interior 66 of load basket 60 will be trapped at the bottom of the load basket. Rather, there is more of a likelihood that the processing fluid will circulate through the body portion 64, so as to more thoroughly mix than if the load basket body portion were constructed in a typical circular cross-sectional shape, such as shown in
Although not shown, holes may be formed in the floor 62 to enable processing medium to pass through the floor thereby to enhance the mixing of the processing medium within the interior 66 of load basket 60 and within the surrounding high pressure chamber within which the load basket is positioned during HPP.
It can be appreciated that the floor 62 may be located at various distances from the bottom of the body portion 64 that would exist if the body portion were not truncated by the floor 62. Although the floor 62 is illustrated as at an elevation of about 70% of the distance between the nominal bottom of a cylindrical body portion and the diametrical center of the body portion, it will be appreciated that the floor 62 can be at other elevations. As a non-limiting example, the floor may be at an elevation from 20 to 80% of the distance above the bottom of the body portion relative to the center of the nominally cylindrically shaped body portion.
Moreover, although not shown, holes can be formed through the thickness of the floor 72. Such holes can function as ejectors, i.e., when the warmer fluid starts to rise inside the vessel the ejectors will pull colder water through the holes, from underneath the floor, and into the interior 76 to get mixed with the warmer water therein.
Also, a support structure 78, which can be similar to support structure 68, can be used to support the load basket for HPP processing.
Various types of materials exhibiting relatively high adiabatic activity can be employed to form the floor 72. For example, such materials might be composed of low-density polyethylene (LDPE), high density polyethylene (HDPE), or ultra high molecular weight polyethylene (UHMWPE).
The load basket 80 has the advantage of the rigidity of a load basket in the form of a complete circle or cylinder cross section at least in the middle and ends of the body portion 82, but at the same time preventing the denser, cooler processing medium to collect and remain stationary at the bottom of the load basket interior 86.
The floor 84 may be constructed of the same material as the body portion 82. Also, holes 88 are provided in the load basket below the level of the floor 82, and holes 89 may also be provided in the floor 84 to perform the same function as the holes in floor 72 described above.
As with the floor 72, the floor 92 can include through holes 99 formed therein to cause the processing medium heated by the floor to pass upwardly into the interior 96 of the body 94, thereby further facilitating the movement of the processing medium within the interior. Further, as discussed above with respect to load basket 80, openings 98 can be formed in the body portion 94 of the load basket below the floor 92 so that pressurized medium 98 is directed to the floor 92 and then upwardly into the interior 96. Further, as with the floor 72, the floor 94 can be composed of various materials, for example, LDPE, HDPE, and UHMWPE.
Although the carrier portion 102 can be constructed in numerous different configurations and profiles, the configuration shown in
As a consequence, by forming the carrier portion 104 from a higher level adiabatic material than the body portion 102, a significant heat source can be provided for heating the processing medium that comes into contact with the surfaces of the carrier portion 104 while also heating the processing medium that flows through the through openings 110 formed in the carrier portion. As explained above, such through openings 110 can function as ejectors wherein the processing medium heated by the carrier portion 104 is ejected into the interior 112 of the load basket.
As most clearly shown in
As also shown in
Although the load basket 100 shown in
Next,
The body portion 121 is shown as being in the shape of a portion of a cylinder. However, the body 121 can be of other cross-sectional shapes, including as a portion of a pentagon, hexagon, octagon, etc. Also, the body 121 can be of a desired diameter or cross-sectional dimension, as well as of a desired length, so as to provide a desired volume for the bulk container as well as a desired aspect ratio (length v. diameter). Thus, the containers 120 can be of the same diameter, but of different lengths so as to be of various volumes and capacities. In this manner, different beverages or other pumpable products can be processed at the same time, when the different products may be of different quantities.
As noted above, the bulk container 120 can be of various sizes and volumes. For example, the bulk containers can have a capacity as small as of about 20 to 25 liters, to a capacity of at least 200 to 250 liters. In this regard, the smallest capacity bulk containers may have a diameter of about 250 to 300 mm, while the larger containers may have a diameter at least 450 to 475 mm. Of course, the bulk container 120 can be of an even smaller capacity and smaller diameter as well as be of an even larger capacity and a larger diameter.
Referring to
It is to be understood that the container end portions 122 can be of a construction and shape other than as shown in
The bulk container 120 can be constructed of various materials, which enable the container to maintain its shape while also being sufficiently flexible to adjust to the reduced volume of the product within the container during HPP. Such reduction in volume may be in a range of 0% to up to at least 30%, thereby requiring the volume of the container to be reduced by this same percentage. The material from which the bulk container may be constructed can include, for example, metallic material or polymer material. Such material, as can be appreciated, must be of sufficient flexural strength and sufficient flexural modulus to enable the container to substantially reduce in volume while being rugged enough for reuse over a desired number of HPP cycles. Such HPP cycles may be an indefinite number of cycles. As such the container can be used indefinitely as long as the container cleaned to meet food cleanliness and other standards.
The typical temperature operating range of an HPP operating cycle is from 0° C. to 50° C. However, the operating temperature may be higher when HPP is used in conjunction with heat pasteurization wherein the operating temperature may raise to 65° C. or perhaps 70° C. The material from which the bulk container 120 is constructed is selected to operate within this temperature range, or perhaps at lower or even higher temperatures.
As mentioned above, the bulk container 120 may be composed of a polymer. As a specific non-limiting example, the polymer may be composed of a thermal plastic, such as polyethylene or nylon. As a further non-limiting example, the polymer may be composed of low-density polyethylene (LDPE), high density polyethylene (HDPE), or ultra-high molecular weight polyethylene (UHMWPE).
As a further non-limiting example, the polymer may have a thickness in the range of from about 4 mm to about 12 mm. The thickness may depend upon several factors, for example, the type of polymer used, the density of the polymer, the diameter of the container, the length of the container, the type of product to be processed, and the pressure level to which the product and container is to be subjected.
The bulk container 120 may be used to process products at high pressures and temperatures than has been the typical operating range for HPP systems. For example, the bulk container may be used operating temperatures of at least 130° C. or higher in situations for both elevated temperatures and pressures are used for sterilization. Such operating pressures may be as high as 8,000 bar or even higher. Many thermal plastics are not designed to operate in these elevated temperatures and pressures. However, “high performance” thermoplastics do exist that are capable to successfully operating at such temperatures and pressures, for example polyetheretherketones, polyamideimides, and polyimides. Also, the thermoplastic may be reinforced with fiberglass or carbon fibers to enhance mechanical and/or thermal properties.
Regardless of the material used to construct the bulk container 120, such material must be compliant with applicable safety standards for food or other products being processed at the operating temperatures being used.
As noted above, the inlet closure, for example valve 123, may be positioned in one or both ends 122 of the bulk container 120 in such a manner that the closure, at least when in closed position, is within the outer envelope of the container. This enables the closure to be easily opened and closed, while still protecting the valve from damage, for example, from adjacent containers during HPP.
The outlet closure may be of the same or similar construction to the inlet closure. Such outlet closure is located on the container body 121. The container body 121 at the location of the outlet closure is recessed so that when the outlet closure is in closed position or configuration, the closure remains within the outer perimeter or profile of the container or within the overall length and width of the container body. As such, the outlet closure is protected from being damaged, or causing damage, by undesirable contact with the HPP vessel or other containers or surfaces during filling, during the HPP process, during removal from the HPP vessel, and during other handling of the container, while still being conveniently opened and closed as necessary.
The features of bulk container 120 described above may be employed in the bulk containers described below and shown in
As shown in
Also, a support structure 148, which can be similar to support structures 68, 78 and/or 128, can be used to support the container 140 for HPP processing.
As shown in
The carrier portion 154 is of substantially solid construction to form the bottom portion of the bulk container 150 so that the container is of cylindrical construction overall as well as to support the bulk container. Thus, the carrier portion 154 has an outer curved cross-sectional shape corresponding to the circumference of the body portion 156 of the bulk carrier 150. The carrier portion 154 may be attached to the body portion 156 by any convenient means.
Further, the carrier portion 154 may be constructed from a material that may be similar to the construction of the carrier portion 104 shown in
A series of blind holes 160 are disposed centrally along the length of the carrier portion. These holes are used to position the body portion 156 relative the carrier portion 154 that includes downwardly extending projections, not shown, to closely engage into the blind holes. Of course, other means can be used to position the body portion 156 relative to the carrier portion 154.
Although not shown, the carrier portion 154 may include projections similar to projections 114 of carrier portion 104 to help restrain the bulk carrier 150 so that the carrier portion remains beneath the body portion 156.
In addition, although rather than being of substantially solid construction, the carrier portion 154 may include cavities or grooves or other features so as to increase the heat transfer area of the carrier portion in a manner analogous to fins in a heat exchanger. As such, the carrier portion would be more efficient in transferring heat from the carrier portion to the work product within the interior volume 152 of the bulk carrier 150.
The bag 170 can be constructed from appropriate commercially available materials, for example rubber or a polymer. Also, appropriate valving maybe utilized in conjunction with the bag 170 for filling and emptying the bag. In addition, the bag may be designed for a single or limited number of uses, or may be constructed for indefinite use. If the bag is designed for more than singular use, it will be necessary to be able to clean and sterilize to bag as required by applicable food handling regulations. Of course, the load basket will also need to be cleaned and sterilized.
The load basket 100 shown in
It will be appreciated that the examples of the load baskets and closed containers disclosed above enable pumpable products to be treated by HPP processing whether the products are prepackaged, for instance in bottles or pouches, or in bulk form in a large thin-walled bulk bag or bladder or in a bulk container that retains its shape but is flexible enough to compress with the compression of the product being treated when subj ected to high HPP pressure. Further, in such HPP processing the containers are constructed to counteract the vertical thermal stratification or layering that commonly occurs in both the processing medium and the product being processed during HPP processing due to the adiabatic temperature rise in the processing medium and the processed product cause by the high pressures imposed during HPP processing. In this regard the containers of the present disclosure may: (1) restrict or remove usage of the lower portion of the pressure vessel, (2) increase the mixing of the pressure media by use of the injector holes formed in, for example, a floor or partition extending across the container so as to avoid a well in the lower portion of the container in which colder processing medium or pumpable product may collect; and/or (3) are constructed so that the lower portion of the container is composed of material exhibiting higher the adiabatic activity or properties than the upper or main body portion of the container.
It also will be appreciated that the various containers described above can be of different lengths, diameters, weights, volumes, wall thicknesses, materials and other parameters depending on, for example, the application being used for HPP processing as well as available pressure vessel size or capacity. Further, the size or capacity of the container will dictate whether or not the container can be manually handled or if auxiliary handling equipment is needed.
It also can be appreciated that by the above construction of the containers 120, 140, and 150 the contents of the containers can be conveniently and safely stored in appropriate facilities both before and after HPP processing, especially at low temperatures, perhaps close to or at 0° C., so as not to permit microbial growth. This is enhanced by the shape and construction of the containers for ease of handling, as well as by their material composition.
Further, it can be appreciated that the containers, bags, bladders, etc., that hold food or other product to be processed are composed of materials that are suitable therefor, and meet all applicable regulations and standards. Further all load baskets, containers, bags, bladders, etc. and cleanable before and/after use as also required by applicable regulations and standards.
While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. For example, in addition to protrusions 114 and supports 68, 78, 128 and 148 discussed above, shims, flanges, rails, bars, runners, slides, circumferentially extending hoop or ring sections or members, and other or similar structures can be used to extend or protrude beneath the container, whether a load basket or a closed container, for supporting the container during the HPP process.
This patent application claims priority of U.S. Pat. Application Serial No. 63/001,047, filed on Mar. 27, 2020, the entire disclosure of which is hereby incorporated by reference herein for all purposes.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/023988 | 3/24/2021 | WO |
Number | Date | Country | |
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63001047 | Mar 2020 | US |