GB2351220A

GB2351220A - Water bottle arrangement for animal cage

Info

Publication number: GB2351220A
Application number: GB9912030A
Authority: GB
Inventors: Edwin Chalk; Robert H Gallagher
Original assignee: Modular Systems & Dev Co Ltd
Current assignee: Modular Systems & Dev Co Ltd
Priority date: 1999-05-25
Filing date: 1999-05-25
Publication date: 2000-12-27
Anticipated expiration: 2019-05-25
Also published as: GB2351220B; GB9912030D0

Abstract

An animal cage comprises a base 1 and a lid 3 removably sealed to the base. An air inlet 35 and an air outlet 37 are provided in one of the base and the lid. An animal-operable non-return valve 71 extends through and is permanently sealed to one of the base 1 and the lid 3 for the passage of drinking water. A bottle 15 may engage non-return valve 71 and remain isolated from the cage interior. The bottle 15 may be refilled through a valve (75, Figure 5) at its end away from valve 71. Details of a seal 29 between base 1 and lid 3 and a clip 55 to retain base 1 and lid 3 together are also disclosed. The air inlets 35 and outlet 37 may incorporate HEPA or roughing filters.

Description

2351220 WATER BOTTLE ARRANGEMENT FOR ANIMAL CAGE This invention relates to

a water bottle arrangement f or an animal cage, particularly a cage f or laboratory animals such as mice, rats, guinea pigs and the like.

It is often necessary to isolate laboratory animals from each other and from laboratory personnel and to this end laboratory animals are kept in sealed cages in order to protect the animals from contamination and/or to prevent contamination of laboratory personnel by such animals.

Nevertheless, it is very difficult to ensure there is no risk of cross -contamination, especially when servicing the sealed cages. In those cages in which a water bottle is contained entirely within the cage, that is those cages which provide isolation at relatively high levels, it is necessary to open and service the cage within a controlled and isolated environment. At lower levels of isolation it is not necessary to provide the water bottle within the cage, which greatly simplifies the daily servicing requirements, but it remains important to provide the maximum degree of isolation possible.

For example, there is described in EP-A-0 724 828 a cage for laboratory animals having various arrangements for a water bottle. A nozzle of the water bottle may extend through an aperture in the cage wall or, at a slightly greater level of isolation, a closure f lap, biased to a closed position, may be provided internally of the cage so as to close the aperture when the water bottle is not present. In order to provide a further level of isolation a frustoconical seal may engage against an outer surface of the water bottle. There are several disadvantages with such arrangements. In each case the nozzle of the water bottle is inserted into and removed from the interior of the cage, thereby inherently introducing cross contamination. In the embodiments providing lower levels of isolation, cross-contamination is possible even when the nozzle of the water bottle has been inserted through the aperture and extends into the interior of the cage.

It is therefore an object of the present invention to provide an animal cage having an external water bottle arrangement and which eliminates or at least reduces the risk of cross-contamination.

According to the present invention there is provided an animal cage comprising a base, a lid removably sealed to the base, an air inlet provided in one of the base and the lid, an air outlet provided in one of the base and the lid and an animal-operable non-return valve extending through and permanently sealed to one of the base and the lid for the passage of drinking water.

The non-return valve may be mounted in a depression provided in the lid, the depression being adapted to receive a water bottle.

The non-return valve may be sealed to the base or the lid by way of a resilient seal, for example of silicone rubber material. A water bottle may be mounted externally of the non-return 10 valve by way of a resilient apertured closure of the bottle. The water bottle may have valve means, for example resilient valve means, provided at a location remote from the apertured closure for introducing water into the drinking bottle from a nozzle of a filling device such 15 as a bottle, water supply line, pump or the like. The cage may incorporate first filter means to filter air flowing into the cage and second filter means to filter air flowing out of the cage The first and second filter means 20 may each comprise a roughing filter or a HEPA filter. The f ilter means may be a push fit with the remainder of the air inlet or air outlet. The lid may be removably sealed to the base by way of a 25 labyrinth seal extending around the peripheries thereof. The labyrinth seal may include an elastomeric seal extending continuously around the seal intermediate the base and the lid. The labyrinth seal may comprise a pair of continuous spaced protrusions provided on one of the base and the lid and a single continuous protrusion provided on the other of the base and the lid and adapted to be received in a space between the spaced protrusions.

The space between the spaced protrusions may be tapered so as to narrow progressively in the direction of insertion of the single protrusion. The elastomeric seal may be provided in the space between the spaced protrusions. The inner of the spaced protrusions may be shorter than the outer of the spaced protrusions so as to engage with the other of the base and the lid in a manner which limits compression of the elastomeric seal. The spaced protrusions may be provided on the lid, for example depending therefrom, and the single protrusion may be provided on the base, for example upstanding therefrom.

The lid may be removably secured to the base, for example by clip means provided around the periphery of the cage, such as at opposite ends and/or sides of the cage.

The air inlet and the air outlet may be provided in the same one of the base and the lid, preferably the lid. The cage may include means for separating inflowing air from outflowing air to promote circulation of air within the cage.

Where the air inlet and the air outlet are provided in the lid, the first and second filter means may be provided within a cut-away portion of the lid. The cut-away portion may be provided with a removable cover.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which:

Figure 1 is a diagrammatic side view, partly cut-away, of one embodiment of an animal cage incorporating a water bottle arrangement according to the present invention; Figure 2 is a diagrammatic end view of the animal cage shown in Figure 1 looking in the direction of the arrow A in Figure 1; Figure 3 is a diagrammatic end view of the animal cage shown in Figures 1 and 2 looking in the direction of the arrow B in Figure 1; Figure 4 is a diagrammatic plan view of the animal cage shown in Figures 1 to 3; Figure 5 illustrates a modification of the water bottle arrangement of the animal cage shown in Figures 1 to 4; Figure 6 is a cross-sectional view of part of a rim of a lid of the cage shown in Figures 1 to 4; and Figure 7 is a cross-sectional view of a clip for securing a lid of the cage to a base thereof.

The animal cage shown in Figures 1 to 7 comprises a base 1 and a lid 3. The base and the lid may be made of a transparent or translucent plastics material such as polypropylene, polycarbonate or polysulphone.

In the illustrated embodiment, the base 1 is formed with a laterally protruding flange 5 having a continuous protrusion in the form of an upstanding peripheral rim 7.

The lower periphery of the flange 5 at each end of the base 1 is formed with a downwardly extending detent 21 which co operates with a retaining clip to be described hereinafter.

The lid 3 is formed with a laterally protruding flange 23 which has a pair of continuous laterally spaced protrusions in the form of a depending peripheral rim 25 and an inner depending rim 27 spaced laterally inwardly of the peripheral rim 25. The peripheral rim 25 extends downwardly beyond the inner rim 27. Thus a recess is formed in the space between the depending rims 25 and 27, the recess accommodating an elastomeric seal 29. The seal 29 may be, for example, of silicone rubber tube (which could have an outer diameter of about 4.4 mm and a wall thickness of about 0.7 mm) formed into a continuous circle or of a strip of cellular plastics material, for example a cellular urethane material (which could have a width of about 4 mm and a thickness of about 3 mm) again f ormed into a continuous loop, such as the material sold under the trade mark PORON.

When the lid 3 is f itted to the base 1, the upstanding peripheral rim 7 of the base extends into the recess between the depending rims 25 and 27 of the lid and compresses the elastomeric seal 29. Overcompression of the seal 29 may be prevented by engagement of the inner 10 depending rim 27 of the lid 3 engaging against the lateral flange 5 to limit penetration of the peripheral rim 7 into the recess between the depending rims 25 and 27. As can be seen from Figure 6, the peripheral depending rim is 25 is inclined outwardly at a small angle cx which may be, for example, about 3 degrees, while the inner depending rim 27 is tapered, being inclined outwardly on the inner face thereof at an angle 0 which may be, f or example, about 5 degrees and being inclined inwardly, more especially 20 towards the free end thereof, at an angle 6 which may be, for example, about 15 degrees. Because of the angles a and 5, the space between the rims 25 and 27 of the lid 3 is tapered and narrows progressively in the direction of insertion of the rim 7 and the rims 25 and 27 serve to 25 guide and lock the upstanding peripheral rim 7 of the base 1 within the recess formed between the depending rims 25 and 27.

The lid 3 is formed on an air inlet side with a gently curved airway guide portion 31 which extends above the food compartment for about two-thirds of the length of the lid.

The airway guide portion 31 terminates in a generally upright wall 33 which is provided with an air inlet aperture having an air inlet tube 35. The lid is formed on an air outlet side with a generally triangular depression 32 adapted to receive the water bottle 15, outflowing air passing to an air outlet aperture having an air outlet tube 37 by way of a region formed between upright wall 33 and a wall 34 spaced from and generally parallel to the wall 33.

The area between the base of the upright wall 33 and the end of the lid is closed by a laterally extending portion 39. The upright wall and the laterally extending portion form a cut-away region which accommodates two filters 41 and 43 such as roughing filters or HEPA filters of conventional design for filtering inflowing and outflowing air. The height of the wall 33 is such that the filters terminate at a level below the top of the wall. The f ilter 43 for outflowing air may incorporate an upstream pre filter to extend the useful life of the primary filter.

Within the curved airway guide portion 31 is an upright dividing wall 45 which extends from the top of the guide portion 31 substantially to the level of the base of the upright wall 33 between the walls 33 and 34. The dividing wall continues as an external wall 46 beyond the wall 34 along the remainder of the airway guide portion 31 and defining one side wall of the generally triangular depression 32. A second side wall 48 of the generally triangular depression is spaced inwardly of the inner peripheral rim 27 and a connecting wall 50 extends between the two side walls 46 and 48 to completely close the depression 32. The dividing wall separates inflowing air from outflowing air and, in combination with the profile of the airway guide portion 31, encourages circulation of air within the cage.

An end of one face of the connecting wall 50 connects with the lower end of the upright wall 34 and a valved drinking spout 71 is permanently mounted (sealed) through the face of wall 50 by way of a resilient seal 73 of silicone rubber or like high-temperature-resistant material allowing a degree of movement. The drinking spout 71 is provided at the end thereof within the cage with a non-return valve which can be operated by the animal(s) in the cage in order to allow water to pass and to obtain a drink. Non-return valves of this type are known per se. Thus the drinking spout 71 protrudes into the space within the cage without substantially endangering the isolation of the atmosphere within the cage. The drinking bottle 15 can be mounted on and removed from that end of the drinking spout 71 protruding externally of the cage by way of a resilient closure having a suitable aperture therein in order to provide fresh drinking water for the animals within the cage.

Figure 5 illustrates a further stage of isolation in which that end of the water bottle 15 remote from the drinking spout 71 is provided with a resilient valve member 75, for example a resilient X-flap valve, which enables the water bottle 15 to be refilled by inserting the spout of a filling device 77, such as a bottle, water supply line, pump or the like, through the valve member 75 in order to refill the bottle 15: thereafter the filling bottle is removed from the valve member 75 which promptly closes to maintain the isolation of the cage.

The filters 41 and 43 are secured to the inlet and outlet tubes 35 and 37 by friction resulting from a taper fit as is widely used for such filters. Inflowing air is supplied to the filter 41 and outflowing air is exhausted from the filter 43 by means of a conventional push fit connection (not shown) employing multiple resilient flanges as is well known for such applications.

The free ends of the filters 41 and 43 terminate within the boundary of the lid 3 and this permits the f ilters to be enclosed within a removable cover 47. The cover 47 slides onto the laterally extending portion 39 of the lid 3 and is secured with a clip 49 which engages in a recess 51 formed at the top of the upright wall 33. An end wall of the removable cover 47 is provided with two apertures 52 and 53 to facilitate passage of the push fit connections (not shown). The removable cover 47 conforms to the general prof ile of the airway guide portion 31 and is aesthetically attractive: however, in addition the cover protects the filters 41 and 43 against accidental knocks and the like.

A grating 9, f or example of metal wire, is supported around the periphery thereof by the flange 5 and is formed with a depression having inclined faces 11 and 13 for receiving food and a water bottle 15. The sides of the depression are closed with metal plates 17 and the food is received in 10 a compartment separated by a metal plate 19. The drinking spout 71 extends through the grating wall of the other compartment formed by the metal plate 19. The lid 3 is removably secured to the base 1 by means of a 15 retaining clip 55 provided in the illustrated embodiment at each end of the lid and co-operable with the downwardly extending detents 21 provided on the lateral flange 5. The clip arrangement is shown in more detail in Figure 7. The retaining clip 55 is pivotably mounted on the depending 20 peripheral rim 25 and is formed with an upwardly extending portion 57 for engaging with the peripheral rim 25 in a resilient manner for limiting opening movement of the clip and with a hooked portion 59 for engaging with the downwardly extending detent 21 of the base 1. Operation of 25 the clip is by way of a depending lever portion 61.

The retaining clip 55 can be opened with minimal movement which is useful in the restricted circumstances of a protective environment. Accidental opening of the clip can be prevented by inserting a locking tie or a padlock (neither of which is shown) between a protrusion 63 formed on the depending peripheral rim 25 and a co-operating protrusion 65 formed on the retaining clip 55.

In use of the animal cage shown in Figures 1 to 7 the filters 41 and 43 and the non-return valve in the drinking spout 71 provide complete and effective isolation at cage level at all times, whether or not the cage is in position on a rack, which has not previously been possible. In combination with a conventional HEPA filtered air supply the animal cage according to the present invention can provide double HEPA filtered air, both in and out of the system.

The labyrinth seal arrangement between the base 1 and the lid 3, preferably with the elastomeric seal 29, effectively prevents egress or ingress of air other than by way of the filters 41 and 43 under both positive and negative pressure regimes. In addition, the filters 41 and 43 allow a certain amount of safe ventilation when the air supply is not present.

All major components of the cage can be washed and autoclaved for cleaning purposes.

Claims

1. An animal cage comprising a base, a lid removably sealed to the base, an air inlet provided in one of the base and the lid, an air outlet provided in one of the base and the lid and an animal-operable non-return valve extending through and permanently sealed to one of the base and the lid for the passage of drinking water.

2. An animal cage as claimed in claim 1, wherein the nonreturn valve is mounted in a depression provided in the lid, the depression being adapted to receive a water bottle. 15

3. An animal cage as claimed in claim 1 or 2, wherein the non-return valve is sealed to the base or the lid by way of a resilient seal.

4. An animal cage as claimed in claim 3, wherein the 20 resilient seal comprises silicone rubber material.

5. An animal cage as claimed in any preceding claim, wherein a water bottle is mounted externally of the nonreturn valve by way of a resilient apertured closure of the 25 bottle.

6. An animal cage as claimed in claim 5, wherein the water bottle is provided with valve means at a location remote from the apertured closure for introducing water into the drinking bottle from a nozzle of a filling device.

7. An animal cage as claimed in claim 6, wherein the valve means is resilient.

8. An animal cage as claimed in any preceding claim and including first filter means to filter air flowing into the cage and second filter means to filter air flowing out of the cage.

9. An animal cage as claimed in claim 8, wherein the first and second filter means each comprise a roughing filter.

10. An animal cage as claimed in claim 8, wherein the first and second filter means each comprise a HEPA filter.

11. An animal cage as claimed in claim 8, 9 or 10, wherein the first filter means is a push fit with the remainder of the air inlet.

12. An animal cage as claimed in any one of claims 8 to 11, wherein the second filter means is a push fit with the remainder of the air outlet.

- is -

13. An animal cage as claimed in any preceding claim, wherein the lid is removably sealed to the base by way of a labyrinth seal extending around the peripheries thereof.

14. An animal cage as claimed in claim 13, wherein the labyrinth seal includes an elastomeric seal extending continuously around the seal intermediate the base and the lid. 10

15. An animal cage as claimed in claim 13 or 14, wherein the labyrinth seal comprises a pair of continuous spaced protrusions provided on one of the base and the lid and a single continuous protrusion provided on the other of the base and the lid and adapted to be received in a space 15 between the spaced protrusions.

16. An animal cage as claimed in claim 15, wherein the space between the spaced protrusions is tapered so as to narrow progressively in the direction of insertion of the 20 single protrusion.

17. An animal cage as claimed in claim 15 or 16 when dependent on claim 14, wherein the elastomeric seal is provided in the space between the spaced protrusions.

18. An animal cage as claimed in claim 17, wherein the inner of the spaced protrusions is shorter than the outer of the spaced protrusions so as to engage with the other of the base and the lid in a manner which limits compression of the elastomeric seal.

19. An animal cage as claimed in any one of claims 15 to 18, wherein the spaced protrusions are provided on the lid, for example depending therefrom, and the single protrusion may be provided on the base, for example upstanding therefrom.

20. An animal cage as claimed in claim 19, wherein the spaced protrusions depend from the lid and the single protrusion expends upwardly from the base.

21. An animal cage as claimed in any preceding claim, wherein the lid is removably secured to the base, for example by clip means provided around the periphery of the cage, such as at opposite ends and/or sides of the cage.

22. An animal cage as claimed in claim 21, wherein the lid is removably secured to the base by clip means provided around the periphery of the cage.

23. An animal cage as claimed in claim 22, wherein the clip means are provided at opposite ends and/or sides of the cage.

24. An animal cage as claimed in any preceding claim, wherein the air inlet and the air outlet are provided in the same one of the base and the lid.

25. An animal cage as claimed in claim 24, wherein the air inlet and the air outlet are provided in the lid.

26. An animal cage as claimed in claim 25, wherein the first and second filter means are provided within a cut10 away portion of the lid.

27. An animal cage as claimed in claim 26, wherein the cut-away portion is provided with a removable cover.

28. An animal cage as claimed in any preceding claim and including means for separating inflowing air from outflowing air to promote circulation of air within the cage.