QUICK FREEZE PALLET RACKS WITH VARIABLE LOUVERED DOORS

Pallet racking systems are designed to quickly freeze items using thermal transfer by moving air through palletized products. Air is pulled through the palletized product to a negative air plenum behind the pallet rack. Back panels of the pallet racks provide variable-height airflow by use of louvers which are individually pressed open by the palletized product to accommodate differing product heights. The panels allow more efficient system operation with any number of rack positions filled.

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.1illustrates an example of a palletized product10suitable for blast freezing. Palletized product10includes a pallet11supporting a stacked arrangement of a plurality of food product containers12with spacers13between rows of containers12. 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 containers12may 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 products10. 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 products20.

In operation, blast freezing room is maintained at approximately −40° F./−40° C. and air handling equipment (typically in the form of fans atop the pallet rack) is activated to direct a flow15of freezing air through the palletized products10at a specified flow rate to quickly freeze the palletized products10. Ideally, the freezing air uniformly flows through spacers13to equally freeze the palletized products10within approximately the same amount of time. However, much of the freezing air follows flow paths17around and between the palletized products10where there is less resistance than flowing through the palletized product10. Less freezing air than desired follows flow paths through spacers13, where flow paths15are in closer contact with the food to be frozen. The limitation in flow through paths is the natural result of flow paths17having less resistance to air flow than flow paths15. Furthermore, the freezing air flowing through the pallets in flow paths15can 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.

Additionally, 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 products10, 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. Meredith discloses that the air flow can be in either direction as may be desired. 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. U.S. Patent Application Publication No. 2011/0107784A1 to Tippmann et al. discloses blast freezing systems with panels that are adjusted by inserting pins at discrete heights to adjust panel opening to accommodate pallets of different heights. However, such systems are labor-intensive, requiring manual adjustment of each of the panels in each rack position. When considered in relation to the variety of shapes and sizes of palletized products and the fact that freezing warehouses may have hundreds of rack positions, the burden of manually adjusting the panels is substantial and renders large-scale deployments of such systems impractical.

Accordingly, there is a need for pallet rack systems with airflow panels which adjust automatically to the height of the palletized goods which are to be subjected to temperature adjustments through thermal transfer of airflow.

SUMMARY

The present disclosure provides for rack systems with airflow openings which are automatically adjusted to open to different heights corresponding to the different heights of various palletized goods placed in the rack for freezing, cooling, or other thermal adjustments. These variable-sized openings increase airflow through the palletized goods, rather than around the edges of the pallet where there would be less resistance, increasing the rate at which the temperature of the goods can be adjusted, which benefits overall system efficiency. Heat transfer may be improved by decreasing turbulence around the pallet. Such improvements 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 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, as the louvered doors automatically seal unfilled rack positions from airflow, thereby preventing wasted resources on cooling (or heating) an empty space. This advantage also avoids manual labor and/or complicated engineering required to reconfigure rack openings when inventory needs require using fewer than all rack positions. Such rack systems may include additional side sealing elements to further increase system efficiencies.

In one embodiment, the disclosure provides a door panel for use in pallet rack assemblies that has a series of louvers mated with a frame, such that the louvers are pivotable to open and close independently to permit airflow through the panel at a variety of different height positions. The louvers may include lever arms which tilt the louvers to the closed position in the absence of pressure from a pallet of goods seated on the rack and against the panel. When palletized goods are placed against the louvers, the lever arms in contact with the goods are pushed to rotate the louvers into the open position, thereby directing airflow through the palletized goods. Preferably, such panels are used in conjunction with a sealed plenum in a single depth pallet rack. Optionally, such louvers (or a portion of such louvers) can be configured such that a certain amount of negative air pressure in the plenum will open the louver, providing an overpressure relief device to prevent the air handling equipment from excess strain.

The disclosure includes pallet racks containing an array of pallet seats adjacent to a plenum, wherein a frame between a pallet seat and the plenum includes a pivoting louver to selectively open the pallet seat to airflow when a pallet is placed in a given seat. Flexible side sheets oriented substantially perpendicular to the frame are deformable upon introduction of airflow to press against the sides of the palletized product, thereby sealing the sides of palletized product from excess airflow and directing more air through the product. In some embodiments, the frame includes uprights with sawtooth openings to receive the louvers, providing easy access for tool-less installation, removal, or replacement of the louvers.

The disclosure includes thermal processing facilities 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.

DETAILED DESCRIPTION

For the purposes 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.

FIG.2illustrates a unique pallet rack assembly incorporating a variable-louvered door. InFIG.2, blast system20has pallet racks21which may contain an array of pallet seats27configured to received palletized products10supported by pallets11. As shown inFIGS.2and3, the system includes two single-depth pallet racks21, each with two columns and two rows of pallet seats27. However, it is understood that different array configurations are compatible with the disclosure herein. Preferably, pallet racks21are single-depth pallet racks and system20has pallet racks21having arrays containing about one (1) to about forty (40) pallet seats27. Pallet racks21may be separated by a plenum which can be sealed on opposing ends by panels23. Fan24may be installed on top of the plenum to draw airflow through the palletized products10, through variable louvered doors26and into the plenum and expel air out the top of the system20. Fan24may be any fixed or variable speed fan compatible with the airflow volumes needed to drive blast system20as known to those of skill in the art, preferably driven by an electric motor. Preferably, fan24may 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. WhileFIG.2shows a single fan24in place for the system20, it is understood that use of additional fans is consistent with the disclosures herein. In a preferred embodiment, pallet racks21may include additional flexible side seals25which adapt to the side profile of the given product10and prevent excess airflow around the palletized goods, as explained further below. Pallet racks21may include pallet guide22which is configured to align palletized products10with the pallet seat27to enhance airflow through the product and improve system efficiency.

FIG.3illustrates an alternate view of the assembly ofFIG.2showing closed doors26in the empty pallet racks. Pallet rack21is shown without any pallets or palletized products in the pallet seats. Side seals25have an arcuate profile that narrows toward the plenum side of the pallet rack21. Each pallet seat is equipped with a variable louvered door assembly26and pallet guide22for aligning a palletized product with the louvered door26, both detailed further below. The quick blast systems20ofFIGS.2-3may 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 trucks in a warehouse 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 system20.

FIG.4is a perspective view of an inventive door panel26included inFIGS.2-3. A frame41surrounds an opening which, when installed in pallet rack assemblies as seen for example inFIGS.2-3, is in between a pallet seat and the plenum. The frame41includes uprights42which are configured with one or more engagement points43. The engagement points receive pivoting elements of louvers44. InFIG.4, there are ten louvers and ten engagement points on each upright, but it is understood that either a larger number or a smaller number of louvers may be used in connection with the inventions claimed herein. Each louver44is equipped with a lever arm45which may bias the louvers to a closed position. For example, lever arms45may be weighted relative to the rest of the louver44such that pressure or force applied to the lever arm45is needed to rotate the louver44to an open position. The preferred arrangements include louvers44oriented to span horizontal sections of the opening between the pallet seat and the plenum. Embodiments of the disclosure includes door panel assemblies which include additional mounting hardware suitable for retrofit installation into existing thermal processing facilities and pallet racks.

FIG.5is a side view of upright42ofFIG.4, showing engagement points43and an edge51. Edge51may have a sawtooth pattern or profile52defining the engagement points43. Although one form of sawtooth pattern is shown inFIG.5, it is understood that other edge profiles are compatible with the disclosures herein. When installed, edge51is preferably oriented facing into the pallet seat (away from the plenum), such that the engagement points are accessible from the outside of the rack structure and blast system. This allows for easy access and installation, removal, replacement, or repair of louvers or louver door assemblies. For example, louver pivots (shown more clearly inFIGS.6A-6C) can be set in or lifted out of engagement points43through the sawtooth pattern52without the use of tools or special equipment. In alternative embodiments (not shown), engagement points43may comprise holes, bushings, bearings, sockets, brackets, or any other receiver member suitable for receiving the pivoting louvers as described herein.

FIG.6Ais a perspective view of a louver compatible with the doors26ofFIGS.2-4. Louver44includes plates47and48which may be referred to as upper plate47and lower plate48relative to the orientation of the louver when installed in doors seen inFIGS.2-4. Louver44includes pivot46associated with plates47,48. Preferably, lever arm45is weighted relative to plates47,48such that the center of mass tends to rotate the louver44about pivot46toward the lever arm45. When installed, upper plate47of one louver may rest against the lower plate48of an adjacent louver to establish a closed position wherein air flow is restricted or diminished. (In the uppermost louver, the upper plate47may rest against a portion of the frame41in the closed position. Similarly, the lower plate48of the lowermost louver may rest against a lower section of frame41in the closed position, rather than another louver.) This has the effect of closing off the pallet seat from the plenum in the horizontal areas of the opening spanned by each louver. InFIG.6A, lever arm45is shown as a generally cylindrical tube or rail which projects from one end of upper plate47, bends to extend along the length of upper plate47, and then bends to return to attach to the other end of upper plate47. However, other forms of lever arms are compatible with the disclosure, for example, one or more bars, tubes, plates, rods, or other structures may extend from the louver plates at a position suitable to bias the louver to a closed position. When the lever arm45is pressed, the louver may rotate the plates47,48relative to the pivot such that the upper plate47is no longer resting against plates of the adjacent louver, establishing an open position where air flow is unimpeded. This is shown and discussed further in connection withFIG.7, below.

FIG.6Bis a rotated perspective view of the louver ofFIG.6A. As seen inFIG.6B, pivots46may be formed from the ends of rod49which extends along the length of louver44. However, other pivot elements such as pins or axles fixed to the ends of the louver44are also compatible with the inventions provided by the disclosure.FIG.6Cis an end view of the louver44ofFIGS.6A-6B. As seen inFIG.6C, preferably, the angle61formed by upper plate47and lower plate48may be obtuse, however, other configurations are possible. In some embodiments, louver44may comprise one plate with an upper section and a lower section. Similarly upper plate47and lower plate48may be oriented at a straight angle (180°). Orienting the plates47,48at an obtuse angle61may facilitate the selective, variable opening of individual louvers44as disclosed herein.

FIGS.7A-7Cshow a palletized product in contact with louvered door assemblies ofFIGS.2-6. InFIG.7A, palletized product10is placed against louvered door26. Upper louvers71are not contacted by the palletized product10and remain in the closed position. Lower louvers75are contacted by the palletized product10and rotated to the open position, exposing horizontal openings76which improve airflow through the product10.FIG.7Bis a view ofFIG.7Awith the palletized product hidden so that the openings76are more clearly visible in the drawing.FIG.7Cis a rotated view ofFIG.7Ashowing that lever arms45of the upper louvers71are not contacted by the palletized product. As the louvers are biased to the closed position, the assembly shown can automatically adapt to any height of palletized product10which is placed into contact with the variable louvered door26. Thus, each of the louvers are rotatable about their respective pivots independent of the rotation of the other louvers. By restricting airflow from going around the product10in the areas of the closed upper louvers71, more airflow is driven through the product10in the areas of the open louvers75, providing for more efficient thermal treatment of the product10. As seen inFIG.7A-7B, open louvers75may be oriented to direct airflow at an upward angle into the plenum and toward fans and air handling equipment (shown inFIGS.2-3). Thus, louvers in the open position act as turning vanes to reduce turbulence and more efficiently circulate air through the thermal processing system, thereby reducing utility consumption.

Although the drawings generally show the louvers44in identical or substantially similar configurations, the louvers may have different properties to enhance operations in particular usage situations or installations. For example, one or more louvers may be configured to overcome the weight of the lever arm to rotate to the open position upon application of sufficient negative pressure from the plenum behind the door panel. Thus, the louver door may act as an overpressure device protecting the air handling equipment from excess strain if an insufficient number of pallets are installed to permit airflow.

FIG.8shows a flexible side seal25first shown above in connection withFIGS.2-3. The view inFIG.8is from the perspective of the front of the pallet rack and shows a left side seal25, although the parts can simply be mirrored about a vertical axis A to provide a corresponding right side seal. Seal25includes a sheet81, back panel82, and front panel83. Back panel82may be affixed to the louver door frame or adjacent structures of the pallet rack surrounding the opening into the plenum. Preferably, as shown more clearly inFIG.10A, back panel81is attached to the a portion of the pallet rack enclosing the plenum space while still permitting access to the uprights and sawtooth openings of the door frame to provide enhanced accessibility to the louver assemblies as described above. Similarly, front panel may be affixed to a front portion of the pallet rack assemblies. Top edge84and bottom edge85are curved such that back panels82of a pair of left and right seals are closer together than front panels83of the pair of seals. This directs airflow through adjacent palletized products (not shown) rather than permitting airflow around the product and through the louver door. Sheet81may be substantially perpendicular to the horizontal door openings. Preferably, sheet81is flexible and deforms under air pressure to conform to the shape of adjacent palletized product. This tight seal forces maximum airflow through the palletized goods, particularly in combination with the variable height doors discussed herein.

FIG.9illustrates pallet guide22previously described in connection withFIGS.2-3above which border pallet seats27(seeFIGS.2-3). InFIG.9, pallet guide22includes side rails91, back rail92, and mounting hardware93for attaching the guide22to pallet racks. Preferably, pallet guide22does not include components on the side of the pallet seat opposite the plenum, thereby providing one open side for access to the pallet seat. This reduces potential for collisions and errors in pallet loading and unloading and provides greater flexibility in system configuration and usage. Pallet guides22may be installed in pallet racks to align palletized products with the plenum openings and louvered doors discussed above. Careful alignment, variable-height door openings, and flexible side seals all contribute to increased airflow through the palletized product and improved thermal transfer and system efficiencies.

FIGS.10A-10Billustrate a partial pallet rack assembly ofFIGS.2-3showing the above-described components ofFIGS.4-9in combination and more detail as a single pallet seat27.FIG.10Ais a perspective view showing pallet seat27bounded by variable louvered door26, flexible left side seal25, flexible right side seal25′, and pallet guide22. As seen inFIGS.2-3, pallet seats27may be arrayed in multiple rows and columns adjacent to a plenum and related air handling equipment and fans. Palletized products may typically be provided on standard heights of pallets such that pallet guides22can be in a fixed height relative to plenum opening provided by door panel26. However, pallet guides22may be provided at differing heights or adjusted to accommodate different sized pallets as needed. Thus, the bottom edge of containers12(seeFIG.1) may be aligned with the bottom of door26when seat27is filled with a palletized product.FIG.10Bis a top view of the pallet seat27ofFIG.10A. As seen inFIG.10B, curved sheets of seals25and25′ may extend inward of the rails of pallet guide22, ensuring a tight fit when palletized products are loaded into seat27. Upon application of airflow, side seals25and25′ will seal against the side of the containers, and airflow above the palletized product containers will be obstructed by the closed louvers of the door26and/or surrounding framing components. Such combinations provide enhanced airflow through the palletized products and increase thermal transfer and system efficiency.