BACKGROUND
Blast freezing is a known process for quickly exposing food products to air chilled to very low temperatures (e.g., −40° F./−40° C.) for a period of time sufficient to completely freeze the food products. FIG. 1 illustrates an example of a palletized product 10 suitable for blast freezing. Palletized product 10 includes a pallet 11 supporting a stacked arrangement of a plurality of food product containers 12 with spacers 13 between rows of containers 12. Such spacers are known in the art for allowing the passage of freezing air between the layers of food product containers. Alternatively or concurrently, the food product containers 12 may have openings in their sides to allow for air flow directly through the containers. In an example conventional blast freezing facility (not shown), a dedicated blast freezing room includes a pallet rack for seating multiple palletized products 10. Pallet rack includes pallet seats arranged in columns, rows, and layers. For example, pallet rack may include four (4) columns and four (4) rows with each row having a depth covering five (5) pallet seats. Thus, at max capacity, such a pallet rack could seat eighty (80) palletized products.
In operation, blast freezing room is maintained at approximately −40° F./−40° C. and air handling equipment (typically in the form of fans) is activated to direct a flow 15 of freezing air through the palletized products 10 at a specified flow rate to quickly freeze the palletized products 10. Ideally, the freezing air uniformly flows through spacers 13 to adequately freeze all of the palletized products 10 associated with a given pallet 11 within approximately the same amount of time. However, if unrestrained, much of the freezing air follows flow paths 17 around and between the palletized products 10 where there is less resistance than flowing through the palletized product 10. Less freezing air than desired follows flow paths through spacers 13, where flow paths 15 are in closer contact with the food to be frozen. The limitation in flow through paths is the natural result of flow paths 17 having less resistance to air flow than flow paths 15. Thus, in the context of a palletized product, there are often paths of less resistance along the outside edges and/or top and bottom sections of a pallet of product, such that it may be difficult and/or inefficient to adjust the temperature evenly across the entirety of the product.
Furthermore, the freezing air flowing through the pallets in flow paths 15 can pass through consecutive pallets and be sequentially warmed by each pallet, so as to make the cooling of the pallets on the exit side slower than those on the entrance side. The flow rate through the series of multiple consecutive pallets tends to have drag. The result is an increase in the amount of time required to adequately freeze all of the palletized products 10, accompanied by the use of colder temperatures from a separate freezing system dedicated to the blast freezing process.
U.S. Patent Application Publication No. 2006/0185528 to Gerald Tippmann et al. discloses an array of palletized products in a warehouse that have a dedicated fan to bring freezing warehouse air rapidly through the palletized products with only a single pallet thickness for the air path without having a dedicated refrigeration system associated with the air handler. U.S. Pat. No. 3,621,672 to Meredith discloses a blast cooling system that uses racks with seals around pathways from an air plenum to force cooling, non-freezing air through palletized food products in a refrigerated warehouse. Along similar lines, U.S. Pat. No. 7,017,366 to Bottom discloses both vertical and horizontal flexible seal elements to engage the palletized product to direct cooling, non-freezing air through palletized product, rather than around it. U.S. Pat. No. 6,340,043 to Paupardin discloses flexible seals for the sides of palletized products in a tunnel arrangement.
While systems using seals to conform to the shape of a stacked product may help prevent some edge leaks, they may be ineffective when the products do not have consistent shapes (e.g., mixed pallets) or other issues disrupting alignment of the seals. Accordingly, there is a need for pallet rack systems which provide a more balanced airflow across the dimensions of a palletized product, including accommodating products which are misaligned, or have irregular or mixed shapes.
Furthermore, attempts to fully seal or contain airflow to only blow through palletized products can burden air handling systems. For example, restricting the return air to product-exposed air can create a large temperature differential between the return air and target temperature of the recirculated air provided by a heating or cooling appliance. Such systems may also require that all positions of the rack be filled in order to effectively operate the system, or may require complicated mechanical doors or panels in order to close off empty pallet positions. There is therefore also a need for pallet rack systems which provide for effective airflow regardless of the number of seats filled and provide mixing of product-exposed air with ambient air to reduce burdens on an air handling system.
SUMMARY
The present disclosure provides for unique panels to separate pallet seats in a pallet rack system from an air plenum shared by the pallet seats and air handling equipment in a thermal processing facility. The panel can provide for improved distribution of airflow across the dimensions of a product subject to thermal processing. The panel can provide for improved distribution of airflow among multiple pallet seats in a pallet rack system, regardless of how many are filled with palletized product(s). Airflow distribution properties of the panels are derived from the placement and configuration of holes or perforations in the panel surface. The perforations may be arrayed across the surface or portions thereof in specific patterns to provide a chosen airflow distribution. The pattern of perforations may be symmetrical about one or more axes of the panel surface. In some embodiments, the perforations comprise multiple patterns, with a first pattern aligned along the center of the panel and a second pattern further outward from the center and toward one or both edges of the panel. The perforations can comprise additional patterns, including a third pattern arranged in segments outside of the second pattern. In a preferred variation, the patterns may have different hole sizes or areas, for example, the holes areas of the first pattern may be greater than the hole areas of the second pattern, the hole areas of the second pattern may be greater than the hole areas of the third pattern. The larger holes provide less resistance to airflow, thereby concentrating airflow through the larger perforations. By accumulating perforation areas toward the middle of the panel, more airflow can be driven through the middle of a pallet of products, thereby providing more balanced airflow and thermal adjustments of the subject products.
The disclosure includes pallet racks and thermal processing facilities incorporating such panels. A pallet rack of vertical and horizontal scaffolding may define pallet seats separated from a common air plenum by framed openings. A panel covering the opening may have an arrangement of perforations configured to more evenly distribute or balance airflow across a dimension of the opening and/or palletized products installed in the pallet seat. In some variations, an adapter substrate extends between segments of the frame to provide for convenient attachment of the panel to the rack structures. The adapter may itself contain holes or apertures and the panel may have corresponding perforations aligning with the apertures. The adapter may further include additional mounting points for attaching seals for further directing airflow through (rather than around) palletized products. Pallet racks may include guide rails spaced to receive and support a pallet and align the pallet with the frame and/or panel.
The disclosure includes thermal processing facilities and systems including the above items in combination with pallet rack assemblies, air handling equipment (e.g., fans), evaporators, condensers, heaters, plenums, and seals, with a preferred application being blast freezing systems. The disclosure also includes methods of adjusting the temperature of goods, for example but not limited to, blast freezing, using the unique panels and rack assemblies discussed herein. The improvements described here may provide various benefits, such as reducing the differential between the product goal temperature and the controlled environmental temperature, reducing capital and utility costs, and improving safety and working conditions for equipment operators. An additional advantage over prior art systems is the fact that the system can be operated when the rack is at any capacity without manual labor and/or complicated engineering required to reconfigure rack openings when inventory or operational needs require using fewer than all rack positions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a palletized product with horizontal ventilating spacers permitting air flow between adjacent layers of product as is known in the art.
FIG. 2 illustrates a perspective view of a blast freezing system including a pallet rack assembly incorporating a perforated panel.
FIG. 3 illustrates a perspective view of the perforated panel included in FIG. 2.
FIG. 4 illustrates a face view of a perforated panel of FIG. 2-3.
FIG. 5 illustrates a partial view of the interior of the pallet rack assembly of FIG. 2.
FIG. 6 illustrates a portion of the pallet rack assembly of FIGS. 2, 5 including a perforated panel, adapter, and side seals.
FIG. 7 illustrates a back or interior view of the subassembly of FIG. 6.
FIG. 8 illustrates a top-down partial view of pallet seat and pallet guide previously included in FIG. 2.
DETAILED DESCRIPTION
For the purpose of promoting an understanding of certain principles of the claimed inventions, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the claims is thereby intended, and alterations and modifications in the illustrated device, and further applications of the principles of the inventions are herein contemplated as would normally occur to one skilled in the art. While the embodiments described below, for example, relate to blast freezing of various products (e.g., fruits, vegetables, meat, seafood, baked goods, etc.) for purposes of illustration, it will be appreciated that the principles of the present description are equally applicable to the blast freezing of any article, and are further applicable to other thermal processing operations driven by airflow, such as cooling, thawing, or warming. Additionally, while directional descriptions of vertical and horizontal dimensions such as upper, lower, above, below, inside, outside, etc., may be used in the context of describing the embodiments discussed herein, the principles discussed herein are applicable to other arrangements depending on the particular operating environment. As one example, the description and drawings may show an air handling fan on the top of a shared air plenum structure in connection with the inventive rack systems. It is nevertheless understood that air handling equipment could be relocated to another part of the structure, unless otherwise specifically described. As another example, the description generally relates to pallets with a foundation structure upon which goods or products are stacked above, as seen in FIG. 1. However, alternative constructions may be considered where the goods are suspended from a shelf, or products or their packaging could be configured to insert directly into a rack system. All of these variations are within the scope of the disclosure, even if not specifically illustrated.
FIG. 2 illustrates an exemplary blast system 20 including a unique pallet rack assembly incorporating a perforated panel 30. In FIG. 2, blast system 20 has pallet racks 21 which may contain an array of pallet seats 27 configured to received palletized products 10 (10a and 10b) supported by pallets 11. As shown in FIG. 2, the system may include two single-depth pallet racks 21, each with two columns and two rows of pallet seats 27. However, it is understood that different array configurations are compatible with the disclosure herein. Preferably, pallet racks 21 are single-depth pallet racks and system 20 has pallet racks 21 having arrays containing about one (1) to about forty (40) pallet seats 27. Pallet racks 21 may be separated by a plenum which can be sealed on opposing ends by panels 23. Fan 24 may be installed on top of the plenum to draw airflow through the palletized products 10, through panel 30, into the plenum, and expel air out the top of the system 20. Fan 24 may be any fixed or variable speed fan compatible with the airflow volumes needed to drive blast system 20 as known to those of skill in the art, preferably driven by an electric motor. Preferably, fan 24 may include a direct drive electronically commutated motor. Such a fan may be modulated between higher and lower airflow settings creating agitation that improves thermal transfer. The top of the rack assembly may be equipped with additional air handling and/or environment equipment.
While FIG. 2 shows two fans 24 at the top of system 20, it is understood that use of a different number of positioning of fans is consistent with the disclosures herein. In a preferred embodiment, pallet racks 21 may include additional side seals 25 to prevent excess airflow around the palletized goods and direct airflow through panel 30, as explained further below. Pallet racks 21 may include pallet guide 22 which is configured to align palletized products 10 with the pallet seat 27 to enhance airflow through the product and improve system efficiency. System 20 is adapted to receive products in differing or multiple heights, such as product 10a which is generally shown as the full height of a pallet seat, or product 10b which is at partial height. System 20 can also be operated with less than all positions or pallet seats 27 filled with product, as seen with open seat 29 in FIG. 2. Further, system 20 may be arranged with a single rack 21 adjacent to a plenum, rather than the two racks 21 seen on opposite sides of the plenum as shown in FIG. 2.
The quick blast systems 20 of FIG. 2 may be used in combination with other features of a thermal processing facility. For example, embodiments may include one or more additional pallet racks for storage separated from the plenum and air handling equipment, which may be arranged in aisles and serviced by fork lifts or other material handling equipment in a warehouse facility. System 20 may be housed in a dedicated freezing room separated from a storage room of the facility. The concentrated airflows provided by the disclosures herein provide rapid thermal adjustment of the palletized product. Upon reaching the desired temperatures, palletized products can be transferred to storage racks and then different inventory units can be processed by the quick blast system 20. Additionally, as system 20 can be operated at less than full capacity, products at desired temperatures can be moved to storage positions and replaced by unprocessed products on a continuous basis while the freezing (or other temperature adjustment) of products in the remaining positions continues uninterrupted.
FIG. 3 is a perspective view of the perforated panel 30 included in FIG. 2. Panel 30 is generally sized to correspond to a framed opening in a panel rack assembly and may take on a variety of dimensions depending on the surrounding structure and installation requirements. Panel 30 has a planar surface 31 having a width dimension and a height dimension. Panel 30 may be relatively shallow in depth, on the order of one-half of one inch (½″). Shallow panel depth may make panel 30 more adaptable for retrofit installations into existing rack assemblies and reduce overall panel weight and material cost. As panel 30 does not have to support structural loads or moving parts, it may be made of lightweight, inexpensive, or easily machinable materials. One preferred material is high-density polyethylene (HDPE). Middle section 34 is configured to align with palletized products installed in a pallet rack, including an exposure width and exposure height which correspond to the expected dimensions of palletized products loaded into a pallet seat. Lower section 36 may be configured to align with the foundation, e.g., the pallet supporting products loaded into the pallet seat or rack assembly, and may align with a lower opening or lower segment of the opening in the framing of the rack assembly. The panel 30 may define an upper section 32 which extends above middle section 34 and/or product heights and is configured to cover the upper part of the opening behind the panel 30. Perforations 40 are arranged across the planar surface 31 to control airflow through the panel and adjacent product installed in the pallet rack, and are preferably arrayed across the middle section 34. The panel 30 may include mounting locations 38 such as holes for accepting fasteners, e.g., bolts, pins, etc., for attaching the panel to underlying structures associated with the pallet rack assembly. Embodiments of the disclosure includes perforated panel assemblies which include additional mounting points and/or hardware suitable for retrofit installation into existing thermal processing facilities and pallet racks.
FIG. 4 is a face view of the perforated panel 30 included in FIGS. 2-3. Perforations 40 may be symmetrical or substantially symmetrical along a central axis of the panel surface, marked line A-A in FIG. 4. Perforations 40 may comprise multiple patterns of hole shapes or sizes, for example, first pattern 41 adjacent to the central axis. A second pattern 42 may be located further away from the central axis relative to first pattern 41. In some embodiments, second pattern 42 has hole size or areas that are smaller than the perforations of first pattern 41. Perforations may comprise a third pattern 43 located still further away from central axis, which in turn may have smaller hole sizes or areas than second pattern 42 and/or first pattern 41. Middle section 32 of the panel may define an exposure height configured to align with the expected maximum height of palletized products above a pallet or foundation, which exposure height may have a horizontal midpoint or axis as shown by the line marked B-B in FIG. 4. In some embodiments, any one or combination of patterns 41, 42, 43 may be symmetrical or substantially symmetrical about the horizontal midpoint. In FIG. 4, there are additional perforations 44 arranged in arrays at the edges of panel 30, in between mounting locations 38. As seen in FIG. 4, edge arrays 44 are not necessarily symmetrical across the same plane marked B-B as the other perforation patterns 41, 42, 43. Nonetheless edge arrays 44 may be symmetrical about other horizontal planes, and/or may be symmetrical about central axis of the panel aligned with the dashed line A-A in FIG. 4. Edge arrays 44 may be aligned with openings in an adapter component of the pallet rack assembly described further below. Sizes or areas of holes in edge arrays 44 may be the same as or different from the other perforation patterns 41, 42, 43.
As thermal processing systems of this type tend to have airflow loss around the outer edges of the product stack, preferred embodiments may have smaller hole sizes toward the outside of the panel and larger hole sizes toward the center portion, thereby directing additional airflow through the center portions of the panel (and product). In the absence of panel 30 with specific perforations 40, a thermal processing system may provide unbalanced airflow properties across the dimensions of the products; in particular, the outer surfaces (including surfaces at the top of the product stack and bottom layers close to the pallet) are adjacent to unconstrained space where there is less resistance to airflow as compared to airflow through the product stack. Thus, the outer surfaces may be exposed to a greater quantity of airflow and therefore have temperatures adjusted unevenly throughout the product stack. The panel 30 with perforations 40 restricts airflow based on the sizes of perforations, thereby redistributing or providing more balanced airflow through the panel 30 and adjacent palletized products. Symmetrical perforation arrangements or geometries discussed above may provide for more balanced airflows (and resulting more even temperature adjustments) across the dimensions of the stacked products.
While shown with four distinct patterns 41, 42, 43, 44 in FIG. 4, it is understood that the panels 30 with a different number of patterns are contemplated and within the scope of the disclosure. For example, the number of distinct patterns may be in the range one to twenty (1-20). Likewise, while perforations 40 are shown in discrete blocks 41, 42, 43, 44, perforations may be provided with holes sizes that generally increase in size from the outer edge toward the central axis, e.g., each vertical column of perforations may have increasing size or area as one moves inward from the edge of panel 30. FIG. 4 illustrates one set of perforations 40 which are configured for use with generally regular product packaging that will have a flat surface pressed against or near the panel. Other configurations of perforations 40 can be adapted for other types of products and/or packaging. For example, a pallet may support pails or barrels which have curved or irregular surfaces adjacent to the panel 30. If the pallet has, for example, four pails across the width of the loaded pallet, perforations 40 could be arranged in patterns configured to align with and concentrate airflow toward the middle of each exposed pail and more restricted airflow in other areas.
While shown as generally circular in FIG. 4, perforations 40 and/or patterns 41, 42, 43, 44, may comprise holes of different shapes, and the shapes of one pattern do not necessarily require using the same shape as another pattern on the same panel 30. Similarly, all holes of a given pattern do not need to be the same shape and/or size. It is also understood that perforations do not need to be uniform areas throughout their depth, i.e., one cross-section of the hole could be narrower or broader than other cross-sections of the hole. The perforations 40 may be generally perpendicular to planar surface 31 as seen in FIG. 4, but in other embodiments may also be angled or slanted, for example, to aim airflow exiting the back side of panel 30 in specific directions that would aid circulation and operation of the overall thermal processing system. For example, panels 30 installed in a bottom layer of a thermal processing system with fans on the top of the air plenum may have perforations more steeply angled to direct airflow upward toward the fan appliance. Thus, perforations 40 may reduce turbulence and more efficiently circulate air through the thermal processing system, thereby reducing utility consumption.
FIG. 5 is a partial view of the interior of the pallet rack assembly 21 of FIG. 2, incorporating perforated panels 30. A combination of horizontal supports 51, 53 and vertical supports 54 define pallet seats 27. For example, the two-by-two array of seats seen in FIG. 5. Horizontal supports 51, 53 may take different forms depending on where the part is used in the assembly. For example, supports 51 are located at the top of the structure shown, but supports 53 are located at the base of a pallet seat 27. Supports 53 may, accordingly, also function as part of a pallet guide structure described further below. A combination of horizontal supports 51, 53 and vertical supports 54 define frames for an opening which is filled or covered by the panel 30. FIG. 5 also shows adapter substrates 55 which may span between segments of the frame. The adapter 55 may provide for convenient attachment of components to the frame and rack assembly 21. For example, adapter 55 may provide for attachment of panel 30 to the rack 21 and/or side seals 25.
FIG. 6 illustrates a mounting arrangement of side seals 25, panel 30, and adapter 55 as viewed from a perspective angle the outside of a pallet rack assembly. Side seals 25 mount to adapter 55 along or outside of the outer edges of panel 30. FIG. 6 also shows edge perforation arrangements 44 as overlapping with the adapter substrate 55.
FIG. 7 is a back or interior view of the subassembly of FIG. 6 showing adapter substrate 55 and perforated panel 30. Adapter substrate 55 may be configured as a casing 71 which defines openings 73 exposed to the panel 30. Openings 73 provide for additional airflow through the panel 30 and any products loaded into the corresponding pallet seat. Perforations in edge arrangement 44 may be aligned with openings 73 to enhance airflow through the panel assembly. Adapter 55 may include frame mounting receivers 77 which are configured to align with mounting locations or hardware of frame or pallet rack structure. Adapter 55 may include panel mounting receivers 78 which align with the mounting locations of the panel (seen best as part 38 in FIG. 3). Seal mounting receivers 79 may be aligned with corresponding mounting locations or hardware of the side seals 25 (seen in FIGS. 2, 5, 6). Receivers 77, 78, 79 may generally be through-holes for receiving standard fasteners such as bolts, pins, screws, etc. The shape of adapter 55 may be modified to accommodate different combinations of pallet racks, pallet seat configurations, or panels. As one example, rather than two adapters 55 as seen in FIG. 7, the adapter could include casing across the upper and lower sections of the opening, effectively defining a smaller, inset opening within the framing of the pallet seat. Accordingly, a standardized or optimized panel and pattern(s) of perforations could be adapted to fit in existing rack assemblies or facilities.
FIG. 8 is a top-down partial view of pallet seat and pallet guide 22 previously included in FIG. 2. Thin perforated panel 30 is toward the back or inward side of the pallet seat. Pallet guide 22 includes back rail (or stop rail) 81, and front rail 82, and side rails 85. Back rail 81 may be mounted to, or integrated into, a framing segment of the overall rack assembly. For example, back rail 81 may be integral with horizontal support 53 seen in FIG. 5. Front rail 82 may be below the plane of side rails 85 as part of the framing structure, thereby providing one open side for access to the pallet seat, as seen in in FIG. 2. This reduces potential for collisions and errors in pallet loading and unloading and provides greater flexibility in system configuration and usage. Returning to FIG. 8, pallet guides 22 may be installed in pallet racks to align palletized products with the plenum openings and panels 30. Side seals 25a and 25b may be substantially mirror images of each other. While seals may be constructed from a variety of materials with different configurations and properties, in a preferred embodiment, seals 25 are substantially rigid panels that direct and concentrate airflow through loaded product and toward the panel 30. In FIG. 8, seal 25 has back portion 86 which is generally parallel or aligned with the side rails 85 and substantially perpendicular to back rail 81. Front portion 88 of seal may be angled outward from the center of pallet guide 22. While flexible seals that conform to the shape of a product are known in the art, such flexible materials may be difficult to work with, particularly with repeated iterations of loading and unloading pallets and contact between the palletized products and the flexible materials. Rigid panels can provide ease and savings in construction, materials, and operation while still providing benefits in concentrating airflow through the products. Rigid panels are likewise compatible with operating the system with open pallet seats, and may assist in squaring the pallet or stacked products in the pallet seat and placement against the panel, improving airflow through the products as well as stability of the stacked products.
This disclosure also includes unique methods associated with making, installing, or operating the structures and systems discussed herein. Methods for adjusting the temperature of goods (e.g., freezing, thawing, cooling, heating) may include loading an unprocessed product into a rack assembly adjacent to an air plenum with a perforated panel installed between the rack and the plenum, operating an airflow system to apply airflow through the unprocessed product and the perforated panel to adjust the temperature of the unprocessed product and thereby create a processed product. In a preferred embodiment, the perforations are configured to concentrate airflow toward a vertical central axis of the perforated panel and restrict airflow toward the outer edges of the perforated panel and may take on a variety of geometries or symmetries and have multiple sets of patterns of perforations, as discussed above. The processed product may be unloaded from the rack assembly, with or without disabling the airflow system driving air through the panel. The rack assembly may be located in a dedicated freezing room of a thermal processing facility, or may be included in a room with storage capacity, for example, storage racks that are not attached to air handling structures. The processed product may be moved to a storage position, such as a storage rack. Storage structures or rooms may be operated at ambient temperatures different from the operating temperatures of the airflow system used in connection with the rack assembly or airflow system used to adjust the temperature of the product.
Making a perforated panel may include various steps, such as: identifying the dimensions and mounting requirements of a pallet seat or rack assembly; providing a panel compatible with the identified dimensions and mounting requirements; identifying a common configuration of goods or packaging that will be subjected to thermal processing; designing a set of perforations configured to concentrate airflow in a desired area of the common configuration of goods or packaging; perforating the panel in accordance with the design. Sizing and perforating the panel may be accomplished using standard machining and fabrication techniques, including drilling, punching, cutting, pressing, casting, blasting, milling, grinding. The panel may be installed in a rack assembly as discussed above. Additional steps may include mounting the panel to the framed opening, with or without an adapter substrate as discussed previously. Adapter substrates may be designed and made in the same manner and in conjunction with the construction of the panel to be compatible with any or all of the framing and mounting requirements of the rack assembly, the perforations and patterns of the panel, and the common configurations of the goods or packaging for a particular installation site.
Patent Application
20250230967
