Liquid purification or separation – Structural installation – Closed circulating system
Reexamination Certificate
2001-01-12
2003-06-03
Prince, Fred (Department: 1724)
Liquid purification or separation
Structural installation
Closed circulating system
C210S175000, C210S232000, C210S235000, C210S238000, C210S416100, C210S460000, C210SDIG008, C099S408000
Reexamination Certificate
active
06572764
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to deep-fat fryers and, more particularly, to a deep-fat fryer cooking oil filtration arrangement.
BACKGROUND OF THE INVENTION
A typical deep-fat fryer will include a fryer vat containing a heating bath of cooking oil. The cooking oil is adapted to receive baskets of food products such that the food products will be immersed within and cooked by the heated cooking oil. Such fryers may also include a heat exchanger and a pump. The pump is responsible for continuously pumping the cooking oil from the fryer vat, through the heat exchanger and back into the fryer vat such that the cooking oil remains at a substantially constant temperature, thereby allowing the food products to be evenly and consistently cooked within the fryer vat. More recently, fryers have been manufactured with in vat fire tubes and associated burners, with combusted gases being passed therethrough to heat the oil, eliminating the need to constantly pump the oil from the vat through a heat exchanger.
To extend the useful life of the cooking oil, it is a common practice to filter the particulate food matter from the cooking oil to minimize the carbonization of such food matter within the cooking oil. Some conventional fryers utilize a batch filtration system, in which the cooking oil is drained from the fryer vat and then manually or mechanically filtered before returning the cleansed cooking oil back to the fryer vat. Other conventional fryers utilize a continuous filtration system, in which a continuous filter is placed within the fluid path of the cooking oil, so as to continuously filter the cooking oil as it is being recirculated between the fryer vat and the pump/heat exchanger.
Previously known batch filtration systems have included oil receiving filtration pans or tanks into which oil from the fryer vat is drained, with a filter assembly placed flat over an outlet port in the bottom of the tank. Such filter assemblies typically utilize a paper filter with a diatomaceous material, sometimes in combination with a screen. These assemblies require some structure atop the paper and filter assembly for holding it in place. Dealing with paper filters can be cumbersome and messy. Similarly, the structure used to hold filters in place can be difficult to handle. Other paperless filter assemblies have been used, with a coupling member separate from the filter assembly providing attachment. Again, such systems can be difficult to handle.
Another issue with prior art filtration systems includes difficulty in cleaning the filtration tank as necessary between filtering operations. Portable filtration tanks/systems on wheels have been used for movement between different fryer devices. Tanks or pans within drawers at the bottom of the fryer device have also been used, but their removability has been limited due to excessive weight, commonly the result of structures attached thereto such as pumps. Further, mating couplers which have been provided in the past with drawer type units have been subject to heavy wear or even damage due to positive latch mechanisms which have been used to hold the drawer in a closed position, as well as due to exposure of seals when the drawer is in an open position.
Additionally, previously known filtration systems have not provided suitable mechanisms for emptying oil into separate containers. For example, one prior art system requires the use of a separate attachment which can be screwed in line with an oil drain path to divert oil away from the normal drain container and into a separate container.
In any deep fat fryer there may also be the problem of debris/particulate build-up in the fryer vat if the particulate does not drain out of the vat during a filtering operation. This has typically been addressed by a manual cleaning of the bottom of the vat which is a less than desirable technique.
Accordingly, it would be desirable to provide an improved fryer filtration arrangement.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a filtration arrangement for a fryer includes a pan for receiving oil from a fryer vat, the pan including an outlet opening, the outlet opening defining a first coupler. A filter assembly includes an interior defined at least in part by an outer filter screen material, a second coupler connected to the filter assembly and defining a passage which extends from the exterior of the filter assembly into the interior. The first coupler and second coupler are sized and shaped for slidingly mating with each other. The first coupler is mated with the second coupler so that oil traveling out of the pan during a filtration operation travels from the pan, through the outer filter screen material, into the interior of the filter assembly, and out of the interior of the filter assembly through a flow path defined by at least one of the first and second couplers.
In another aspect of the invention, a filtration arrangement for a fryer includes a fryer vat and a pan for receiving oil drained from the fryer vat, with a filter assembly within the pan for filtering oil passing through the pan. An oil drain path leads from an outlet opening of the fryer vat to the pan, and an oil return path leads from the pan back to an inlet opening of the fryer vat. A lower portion of the fryer vat is shaped to direct particulate matter which settles in the fryer vat into a substantially linear region along a bottom surface of the vat. The fryer vat inlet opening is positioned at one end of the substantially linear region and the fryer vat outlet opening being positioned at an opposite end of the substantially linear region for causing oil being circulated during a filtration operation to flow from the fryer vat inlet opening, along the substantially linear region and out the fryer vat outlet opening to push particulate matter lying in the substantially linear region toward and out of the fryer vat outlet opening for delivery to the pan.
Still another aspect of the invention provides a filtration arrangement for a fryer including a fryer vat and a pan for receiving oil drained from the fryer vat, with a filter assembly within the pan for filtering oil passing through the pan. An oil drain path leads from an outlet opening of the fryer vat to the pan, and an oil return path leads from the pan back to an inlet opening of the fryer vat. A latch-free drawer is movable between open and closed positions relative to a fryer frame, and the pan is positioned in the drawer. During a filtration operation oil is drawn out of the pan along the oil return path and delivered back to the fryer vat. The oil return path is defined in part by a return coupler connected to and extending from a portion of the pan. The return coupler is aligned for slidingly mating with a corresponding coupler on the fryer frame when the drawer is moved to a closed position. The oil is drawn out of the pan along the oil return path in a manner which creates a suction force for holding the return coupler of the pan to the corresponding coupler of the fryer frame so as to maintain the drawer in a closed position during a filtration operation.
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Illinois Tool Works Inc.
Prince Fred
Thompson Hine LLP
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