Animal husbandry – Confining or housing – Often portable – small capacity – roofed housing structure
Reexamination Certificate
2000-04-18
2001-09-25
Jordan, Charles T. (Department: 3643)
Animal husbandry
Confining or housing
Often portable, small capacity, roofed housing structure
C119S458000
Reexamination Certificate
active
06293229
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to animal cages and, more particularly, relates to a flood prevention system for use in a ventilated small animal cage and to a cage having a flood prevention system.
2. Discussion of the Related Art
Ventilated cages are widely used in research facilities for housing lab animals such as mice and rats. The cages typically are provided in a cage and rack system in which a number of rows of cages are mounted on stacked shelves. In order to prevent the air in each cage from contaminating adjacent cages, all of the cages of the typical system of this type are ventilated using a common air supply duct that supplies air to the cages and a common exhaust manifold that draws air out of the cages, thereby leaving a slight positive pressure in the cages. The animals therefore remain isolated from one another to prevent the transfer of diseases. Systems of this general type are disclosed in U.S. Pat. Nos. 5,954,013; 5,349,923; and 5,148,766, all of which are assigned to Lab Products, Inc.
The cages may be supplied with drinking water either by individual water bottles or by a water supply manifold and a plurality of animal watering valves, one of which is accessible from each cage. When a water manifold and animal watering valves are employed to supply drinking water to the animal, each cage may be coupled to both the air supply duct and the water supply manifold by a common docking assembly that extends into the front wall of the cage.
Water supply valves and water bottles sometimes leak, potentially flooding the bottom of the cage and endangering the animals housed in the cage. If the cage is provided in a cage and rack system, the flooding danger extends to cages adjacent the cage with the leaking water bottle or watering valve. Prior known-cages lacked any measures to prevent cages from flooding and also lacked adequate measures to channel any water that leaked from a watering valve or bottle away from the cage. The need therefore has arisen to provide a drain for draining water from a leaking water supply valve or water bottle away from a cage, thereby preventing the cage from flooding. However, in order to minimize or prevent the air in the cage from contaminating the adjacent cage, an acceptable flood prevention system should not unnecessarily destroy the atmospheric integrity of the cage by allowing it to be contaminated with room air.
Even an adequate drain would not solve all problems associated with a leaking water bottle or watering valve. Most cages have wood chips or another water-absorbent bedding strewn about their floors. This bedding may become saturated if a water bottle or watering valve leaks and remain damp for a substantial period of time thereafter, even if all standing water were to be drained from or otherwise removed from the cage. Wood chips are particularly problematic because they act as wicks to draw water from the flooded portion of the cage to other portions that would otherwise remain dry. Damp bedding poses a substantial source of discomfort to animals housed in the cage and may pose hypothermia and other health risks to the animals. These risks are particularly high in ventilated cages because the animals may be chilled by airflow through them. The need therefore has arisen to provide a safe haven that remains dry even if the bedding in the cage becomes saturated from leaking or spilled water.
SUMMARY OF THE INVENTION
Pursuant to the invention, a method and an apparatus are provided for preventing a cage from flooding if water spills or leaks into the cage.
The apparatus comprises a self-sealing drain valve that is mounted in the floor of a ventilated cage that automatically opens to drain flood water from the cage and that otherwise is sealed to maintain atmospheric integrity within the cage. A preferred drain valve includes a perforated drain cup, a perforated seal cup, and a drain seal all held together by a connector such as a rivet. The perforated drain cup extends above the bottom surface of the cage a small amount so as to form a collector for water leaking into the cage, and the perforated drain seal extends downwardly from the drain cup to present a valve seat. The drain seal preferably comprises a resiliently flexible diaphragm which normally seals against the valve seat of the perforated drain seal. However, if the cage floods such that liquid accumulates in the perforated drain cup, the weight of the liquid forces the drain seal away from the valve seat on the perforated seal cup to permit the liquid to drain away from the cage.
The cage may also be provided with protective structures that provide a safe haven for an animal in the event of water bottle or water supply valve leakage. These structures are desirable because, even when the drain valve works properly, bedding within the cage may absorb a significant amount of liquid so that the cage remains damp even after the liquid drains out of the cage through the self-sealing drain valve.
For instance, a tray may be provided for the animal to climb into to avoid damp bedding within the cage. The tray may comprise a simple open-topped tray whose walls are sufficiently high to be above the level of the bedding in the cage but sufficiently low for the animals(s) in the cage to climb into. The animals can simply climb into the tray and stand in it if the bedding becomes wet, thereby providing the animals with the opportunity to remain dry until the cage can be cleaned. The tray preferably is made of metal or another structure that is too hard for animals to gnaw into.
In the alternative, a partition can be mounted or molded into the cage to separate the back end of the cage from the front end that contains the bedding. In a preferred embodiment, the partition is formed integrally with the cage and has a metal guard clipped over its upper edge to prevent the animal from gnawing into the partition.
These and other advantages and features of the invention will become apparent to those skilled in the art from the detailed description and the accompanying drawings. It should be understood, however, that the detailed description and the accompanying drawings, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
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Boyle Fredrickson Newholm Stein & Gratz S.C.
Edstrom Industries, Inc.
Jordan Charles T.
Shaw Elizabeth
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