Food or edible material: processes – compositions – and products – Processes – Packaging or treatment of packaged product
Reexamination Certificate
1999-10-18
2001-02-27
Brouillette, Gabrielle (Department: 1761)
Food or edible material: processes, compositions, and products
Processes
Packaging or treatment of packaged product
C426S401000, C426S405000, C426S412000, C426S520000, C426S521000, C099S483000
Reexamination Certificate
active
06194015
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to heat exchange systems and, more specifically, to apparatus and methods for heating or cooling product containers, for example, filled with liquid-based food product.
BACKGROUND OF THE INVENTION
In many food processing operations, such as in the processing of fruit and vegetable products, the food product must be heated and maintained at a sterilizing temperature and then cooled sufficiently to allow further packaging and transport. After proper heat sterilization, the product is either cooled and then packaged under aseptic conditions, or the product is immediately packaged in a heated, sterile condition and then cooled to a temperature sufficient for additional packaging and shipping. The product may also be packed cold in a container, and then sealed, sterilized and cooled in the container. Cooling the sterilized food product while the product is sealed within a container, such as a flexible bag, eliminates the need for filling sterile bags with cooled, sterile food product under aseptic conditions. Instead, the bag may be filled with heated, sterilized food product and sealed to ensure that the food product remains sterile. To achieve acceptable cooling times, complex cooling equipment has generally been designed to accommodate specific package types. On the other hand, simpler conveying systems that merely spray the packages with chilled liquid result in longer cooling times and, therefore, higher processing costs.
Many different systems have been proposed and used for continuously heating and/or cooling containers of food product along a moving production line. As mentioned above, some of the more complex systems include mechanisms or structure for agitating the food contents as the containers are heated or cooled by liquid or gas heat transfer media. For example, cans of liquid-based food product have been agitated back and forth or rolled as a conveyor moves the cans past nozzles that spray the cans with a heat transfer liquid. With other equipment, pouches or bags have been manipulated by rollers or rocked back and forth on specialized carriers while the pouches are conveyed through a heat transfer media.
To address various problems of the past, it would be desirable to provide apparatus and methods for heating and/or cooling product quickly and uniformly, whether the product is packaged in a rigid or flexible container.
SUMMARY OF THE INVENTION
The present invention therefore generally provides apparatus for transferring heat between a heat transfer liquid and a plurality of flexible or rigid containers filled at least partially with food product. The apparatus may comprise essentially one module or a series of modules linked to form a longer system. The apparatus generally comprises a perforated conveyor having a conveying surface for supporting the containers and transferring the containers through a housing structure. A conveyor pan receives the perforated conveyor and includes an open top portion and at least one drain. The conveyor pan holds a continuously recirculating pool of heat transfer liquid at a level disposed above the conveying surface of the perforated conveyor. In this manner, heat is transferred between the pool of heat transfer liquid and the contents of the containers. In addition, a heat transfer liquid distributor is spaced above the perforated conveyor and showers the containers with heat transfer liquid directed through the open top portion of the conveyor pan. This effects further heat transfer between the showering liquid and the contents of the containers. Finally, a vibrator unit is operatively connected with the conveyor pan and vibrates the conveyor pan, the perforated conveyor, the pool of heat transfer liquid and the containers of food product as the containers are moved by the conveyor. Uniform, efficient heat transfer therefore occurs between the heat transfer liquid and the food product in the containers. The apparatus accomplishes this result while also being easily incorporated into existing processing operations and being versatile enough to accommodate a wide variety of container sizes and types.
In the preferred embodiment, a conveyor support contacts the perforated conveyor and is mounted along a bottom surface of the perforated conveyor pan to transmit vibrations between the vibrator unit and the perforated conveyor. A liquid return pan is mounted below the conveyor pan for receiving the heat transfer liquid from the drain. The liquid is drained in a continuous manner or, in other words, in a manner which maintains a predetermined liquid pool level that partially submerges the containers moving along the conveyor. The drain of the conveyor pan preferably comprises multiple perforations in a lower surface of the conveyor pan. These perforations generally occupy an area opposed to the conveying surface such that the pool of heat transfer liquid drains across the conveying surface in a generally uniform manner. The perforated conveyor is a continuous conveyor that has a lower portion passing through the liquid return pan. The perforated conveyor additionally includes a plurality of high friction elements on the conveying surface for maintaining the containers in contact with the perforated conveyor and moving through the pool of liquid. Other structure may be provided for this purpose in addition or as an alternative to the high friction elements.
The housing structure includes an inlet end and an outlet end and the perforated conveyor is more specifically a flexible belt having portions disposed generally at the inlet and outlet ends. Guide elements contact these portions of the belt and direct the belt downwardly into the conveyor pan. The liquid distributor is preferably a liquid distributing pan adapted to hold a volume of the heat transfer liquid. The liquid distributor pan includes a lower, perforated surface generally occupying an area opposed to and covering the conveying surface of the perforated conveyor. Therefore, the liquid distribution pan uniformly showers the containers on the conveying surface with chilled or heated liquid. A heat exchanger receives the heat transfer liquid in a recirculation path generally between the conveyor pan and the liquid distributor pan to continuously heat or cool the liquid. Finally, a plurality of pneumatic vibration dampeners are mounted between the housing structure and the conveyor pan and, more preferably, between a conveyor pan support structure and the conveyor pan. These devices isolate vibrations of the conveyor pan from the remaining portions of the housing structure, and provide height adjustment to maintain the conveyor pan at optimum operational height.
The invention is also directed to methods for effecting heat transfer between a plurality of containers filled with food product and a heat transfer liquid. These methods may be performed using apparatus as generally described above, and involve moving the plurality of containers along a perforated conveyor which is positioned to partially submerge the containers within a pool of the heat transfer liquid. Heat transfer liquid showers the containers as they move along the perforated conveyor. The pool of heat transfer liquid is drained to maintain a level that partially submerges the containers. Finally, the perforated conveyor, the pool of heat transfer liquid, and the containers are vibrated during the conveying and showering operation to agitate the product within the container and effect more uniform heat transfer.
Various additional objects, advantages and features of the invention will become more readily apparent to those of ordinary skill in the art upon review of the following detailed description of the preferred embodiment taken in conjunction with the accompanying drawings.
REFERENCES:
patent: Re. 31513 (1984-01-01), Glen
patent: 1570235 (1926-01-01), Fooks
patent: 1835799 (1931-12-01), Meyer
patent: 1948790 (1934-02-01), Grayson
patent: 1961337 (1934-06-01), Cornell
patent: 2254420 (1941-09-01), Cleveland
patent: 2274292 (1942-02-01), Hiller, J
Brouillette Gabrielle
Dauerman Sherry A.
FMC Corporation
Wood Herron & Evans L.L.P.
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