WO2003096801A1

WO2003096801A1 - Perfect airtight-type cage system for protecting transition of pathogen

Info

Publication number: WO2003096801A1
Application number: PCT/KR2003/000993
Authority: WO
Inventors: Jae-Jin Jang; Han-Woong Lee
Original assignee: Orient Co., Ltd
Priority date: 2002-05-22
Filing date: 2003-05-20
Publication date: 2003-11-27
Also published as: AU2003235284A1; KR100479022B1; KR20030090896A

Abstract

Disclosed herein is a cage system for breeding experimental animals, in which the experimental animals are bred while being shielded from pathogens. The cage system includes a water tub (120) equipped with a tank having an opening, a nozzle, and a sealing lid having a bore for inserting the nozzle therethrough and plugged in the opening of the tank, and a fodder tub (130) having fodder discharging slots positioned at predetermined intervals. The cage system also includes a housing equipped with a main body acting as a space in which the experimental animals are bred and a cage cover having a water-tub receiving groove and a fodder-tub receiving hole. A fodder-tub receiving hole cover (108) functions to airtightly seal the fodder-tub receiving hole. Clamps (160) are mounted on a front and a rear side of the main body to combine the main body with the cage cover.

Description

PERFECT AIRTIGHT-TYPE CAGE SYSTEM FOR PROTECTING TRANSITION OF PATHOGEN

Technical Field

The present invention relates, in general, to a cage system for breeding experimental animals and, more particularly, to a cage system on which a feed canister and a water canister can be detachably mounted in an airtight manner so as to breed experimental animals in a safe atmosphere protected from being contaminated with various bacteria and airborne contaminants.

Background Art

As a rule, the development of new medicines is forced to pass validity experiments to confirm both the effects and safety of the new medicine in advance. In this regard, the experiments are usually made on animals in order to identify the clinical side effects of the newly developed medicines on humans in advance. Of the animals used for the testing validity of medicines, mice are the most preferable ones due to their high fertility.

In order to guarantee experimental reliability, experimental animals such as mice must be bred in clean rooms satisfying specific requirements. Because of the high costs of their installation and maintenance, clean rooms have been, in most cases, managed in large-scale facilities of companies. Actually, most of the laboratories of universities or small-to-medium-sized enterprises have brought experimental animal models from such companies because they are not equipped with clean rooms. However, such laboratories must secure reliability and safety in experiments with animals. For example, experimental animals should be kept alive despite infection in a long-term carcinogenicity study or toxicity experiments. Additionally, even though various kinds of animals, such as a group of germ-free animals and gnotobiotic animals, are bred, they are segregated from each other even in the same space so that they are prevented from interacting. As a matter of course, the breeder should be protected from being infected from the animals. In order to better understand the background of the invention, a description will be given of prior arts with reference to accompanying drawings.

Fig. 1 is a schematic perspective view showing a cage rack system for holding multiple cage systems for breeding experimental animals therein. A conventional experimental animal breeding cage system held in the cage rack system is shown in a perspective view in Fig. 2, in a partially exploded view in Fig. 3, in a front view in Fig. 4, and in a side view in Fig. 5. Fig. 6 is a sectional view showing a structure for seating a water canister on the cage system shown in Fig. 2. Fig. 7 is a sectional view showing a structure for seating a feed canister to the cage system shown in Fig. 2.

Each conventional experimental animal breeding cage system 1 is designed to breed five or six experimental animals, such as mice, at the same time. For practice, the experimental animal breeding cage system 1, as shown in Fig. 1, is disposed in the cage rack system 10 capable of accommodating several experimental animal breeding cage systems. However, the experimental animal breeding cage system 1 may be utilized alone with the independence of the cage rack system 10.

The cage rack system 10 comprises an air supply means 11 by which fresh air is drawn from the outside, filtered and supplied to the cage systems 1, and an air exhaust means 18 for discharging the air from the cage systems 1 to the outside. The air supply means 11 comprises an air supply nozzle 14 which supplies fresh air into the cage systems 10 therethrough, while the air exhaust means 18 comprises an air exhaust nozzle 15 which exhausts contaminated air from the interior of the cage systems 1 to the outside.

Mounted in the cage rack system 10, each cage system 1 is air-conditioned in a forced air circulation manner to receive fresh, aseptic air from the outside and exhaust contaminated air from the interior.

As shown in Figs. 2 and 3, the conventional experimental animal breeding cage 1, which may be formed of polycarbonate, is comprised of a box-shaped container 2, and a cage lid 3 that is engaged with the top of the container 2 to form a sealed housing 20 and that has a depressed receiving portion 21 in which both a feed canister 4 and a water canister 5 are seated, with the nozzles of the feed canister 4 and the water canister 5 inserted, in an airtight manner, into the interior of the container 2.

On the rear-side of the box-shaped container 2 are formed an air inlet unit 6 and an air outlet unit 7 which are designed to communicate with the air supply nozzle 14 and the air exhaust nozzle 25 of the rack system 10, respectively, when the container 2 is mounted in the rack system 10. A ventilation unit 8 is established on the cage lid 3 of the cage system 1 so that when the cage system 1 is separately utilized, filtered air can be supplied into the interior of the cage system 1 while the air inlet unit 6 and the air outlet unit 7 are closed.

A detailed description will be given of the construction of the cage system with reference to Figs. 4 and 5. As shown in the drawings, a pair of locking units 22a and 22b are attached to both sides of the cage lid 3 so as to prevent the cage lid 3 from being undesirably separated from the container 2, after the cage lid 3 is engaged with the container 2 in an airtight manner. An O-ring 23 is fitted into a packing groove formed on the bottom surface of the peripheral portion of the cage lid 3 so as to allow the cage lid 3 to be securely engaged with the container 2 in an airtight manner.

The locking units 22a and 22b have such a structure that its upper ends are attached by hinges to the peripheral edge of the cage lid 3 and its locking members 22c and 22d inwardly projected from the handles of the locking units 22a and 22b are engaged with the fixing projections 2a and 2b.

The air inlet unit 6 and the air outlet unit 7 are similar in their sealing structure. In each of the units 6 an 7, a first bracket 93, in the depressed portion of which a center hole 93a is formed, is interlocked in an airtight manner with a second bracket 96, in which a center hole is formed, through a hole formed in the container 2. The fi-rst and second brackets 93 and 96 are fixedly attached to the box- shaped container 2 with their circumferential portions being sealed.

A moving member 97, partially inserted into the center hole 93a while being supported by an elastic spring 94 and provided with a plurality of air inlets 95, is elastically supported in the depressed portion of the first bracket 93. A stem 91b which extends from the center to the outside while closing the air inlets 95 formed on the moving member 97 is fixed by a nut 98 and attached to a sealing plate 91 at the peripheral portion of which a plurality of holes 91a are formed.

In a normal state in which the cage system 1 is not connected with the cage rack system 10, the sealing plate 91 is brought into tight contact with the moving member 97 by the elasticity of the elastic spring 94, thereby sealing the cage system 1 from the outside.

On the other hand, when the cage system 1 is mounted in the cage rack system 10, the elastic spring 94 is compressed by the pushing of an air supply nozzle 14 and an air exhaust nozzle 15. Accordingly, the moving member 97 is brought into contact with the depressed portion of the first bracket 93 and, simultaneously, the sealing plate 91 is moved into the interior of the container 2, thereby breaking the seal. As a result, the air supply nozzle 14 and the air exhaust nozzle 15 each communicates with the interior of the cage system 1 through a plurality of air inlet holes 95 formed on the moving member 97, so that air is supplied into and exhausted out of the interior of the cage 1. As depicted in Fig. 6, a water canister 5, made of transparent or translucent polycarbonate, is comprised of a water canister body 51 provided on its outer surfaces with scales indicating the amount of remaining water, a sealing member 52 tightly fitted into an opening 51a of the water canister body 51 and provided with an insertion hole 52a longitudinally passing through the sealing member 52, and a water canister nozzle 53, tightly fitted into the insertion hoie 52a of the sealing member 52, for discharging water contained in the water canister body 51 by suction therethrough.

The water canister nozzle 53 is detachably fitted, in an airtight manner, into a first airtight connecting unit 50 formed at the depressed receiving portion 21 of the cage lid 3. A feed canister 4 for feeding test animals, as shown in Fig. 7, is comprised of a cylindrical body 61 formed of transparent polycarbonates, open on its top and bottom to supply feed, and provided with a plurality of locking holes 64 oppositely situated on the peripheral edge of the lower end of the cylindrical body 61, a feed canister lid 63 for selectively opening or closing the top of the cylindrical body 61 and isolating the interior of the cylindrical body 61 from the outside when assembled with the cylindrical body 61 to prevent experimental animals and feed from being, contaminated, and a feed canister nozzle 62 formed of stainless steel to form a plurality of feed discharge holes 62a and attached to the bottom of the cylindrical body 61.

The feed canister nozzle 62 is detachably fitted, in an airtight manner, into an airtight connecting unit 60 formed in the depressed receiving portion 21 of the cage lid 3.

However, the cage system of the prior art suffers from the disadvantages of stress to the experimental animals and being difficult to manage.

While experimental animals are bred in the rack system, the rack system must be perfectly airtight except for the entrance and exit through the air supply nozzle and the air exhaust nozzle. However, when the cage system is mounted in the rack system, imperfect airtightness is found in the airtight connecting area, composed of a guide bush made of rubber and a bracket made of strainless steel, for mounting the feed canister on the cage system. Additionally, when the feed canister, composed of the feed canister nozzle and the cylindrical body, is detached out of the cage lid in order that the feed canister is washed or supplied with feed, the feed canister nozzle and the cylindrical body must be separated, causing an inconvenience while a user handles it.

As for the water canister for supplying animals with water, the water canister nozzle through which water is discharged by suction is so vertically attached to the airtight connecting unit for mounting the water canister on the cage lid that the experimental animals must hold their heads high to drink water, which builds up stress and thus negatively influences test data.

In the cage system of the prior art, the 0-ring is fitted into the packing groove formed on the bottom surface of the peripheral portion of the cage lid so as to allow the cage lid to be airtightly engaged with the container. However, when the cage system is sterilized by autoclaving, the O-ring is exposed to a high temperature and pressure and thus deformed, so that it easily departs from the packing groove of the cage lid. As described above, the locking units, provided to lock the cage lid to the box-shaped container, are installed in the cage lid. However, when the locking units are loosened and the cage lid is lifted in order to wash the interior of the cage system, the locking members are caught on the circumference of the upper portion of the box-shaped container and thus are difficult to separate from the cage system. In addition, the locking units can function to engage the container with the cage lid even though the cage lid is not accurately positioned on the container. Accordingly, without great care, the experimental animals may be bred under the condition in which the cage system is not kept airtight. Moreover, while the air inlet unit and the air outlet unit of the prior cage system are not engaged with the air supply nozzle and the air exhaust nozzle, respectively, the moving member is brought into contact with the sealing plate to block the entrance and exit of air. However, it is difficult to keep airtightness between the moving member and the sealing plate because both of them are made of stainless steel.

Summary of the Invention With the above problems in mind, the present invention has an object of providing a cage system which is so airtight that experimental animals are bred therein with great safety by preventing the introduction of various bacteria into the cage system and which can be used even in a laboratory without a clean room.

It is another object of the present invention to provide a cage system for breeding experimental animals with much less stress. It is a further object of the present invention to provide a cage system for breeding experimental animals, which is easy to handle and manage.

In accordance with one aspect of the present invention, there is provided a cage system for breeding experimental animals, comprising: a water canister comprising a tank provided with an opening; a nozzle through which water is exhausted by the suction of the experimental animals; and a sealing member tightly fitted into the opening and provided with an insertion hole into which the nozzle is inserted; a feed canister provided with a plurality of feed exhaust slots at regular intervals; a housing comprising a conta^'iner for accommodating the experimental animals; and a cage lid on which a water canister-receiving depression and a feed canister-receiving depression are formed; a feed canister-receiving depression lid for blocking air from entering through the feed canister-receiving depression; and a pair of clamps, formed on front and rear sides of the container, for locking the cage lid to the container.

In the cage system, the feed canister-receiving depression is provided at its circumstance with an upwardly protruded flange with which the feed canister-receiving depression lid is engaged. The feed canister is provided with a fixing flange extending from the upper circumference of the feed canister, and the feed canister-receiving depression is provided on its inner circumferential surface with a support flange for supporting the fixing flange. The tank has a first inclined wall on which the opening is formed, and the water canister-receiving depression has a second inclined wall standing at an angle corresponding to that of the first inclined wall of the tank and is provided on the second inclined wall with an airtight connecting means for airtightly supporting the nozzle of the water canister.

The first inclined wall of the tank stands at an angle of 30-50 degrees.

Each of the clamps comprises a knob member whose upper portion is engaged with the container by a hinge, and a locking member whose lower portion is engaged with a middle portion of the knob member by another hinge and which has, at an upper portion thereof, a locking groove that is brought into contact with the external circumference of the cage lid when the clamps are applied to the cage lid, and the cage lid is provided with at its external circumference with a fixing projection which is interlocked with the locking groove. The cage system further comprises: a packing member provided with a plurality of connecting projections which are extended downwardly to airtightly engage the container with the cage lid; and a packing groove on which the packing member is mounted and which is formed on the upper circumference of the container and provided with a plurality of connecting holes at positions corresponding to those of the connecting projections .

The cage system further comprises: an air inlet unit, formed on a rear side of the container, for supplying air to the interior of the housing, and an air outlet unit, formed on the rear side of the container, for exhausting air out of the housing, each of the air inlet and outlet units being fitted into a hole formed on the rear side of the container, and comprising: a first bracket which is provided at its central depressed portion with a first center hole, at a periphery of which a plurality of air inlets are formed; a second bracket, having a second center hole at its center, interlocked with the first bracket through the hole with circumferential portions of the first and second brackets being sealed; a moving member, whose circumferential portion is elastically supported in the depressed portion of the first bracket by a spring and which is provided with a third center hole communicating with the first center hole and with a plurality of air inlets at the periphery of the third center hole; a sealing plate, in close contact with an inner surface of the depressed portion of the first bracket while being geared with the moving member so as to close or ^' open the air inlets of the first bracket; and a sealing ring attached to the contact surface of the sealing plate.

The air inlet unit comprises a protecting cap, provided in the inner side of the first bracket, for preventing generation of noise attributed to the contact with the experimental animals with the air inlet unit and averting impurities from being inserted into the air inlet unit.

The air outlet unit comprises a cage outlet filter which is detachably mounted on the first bracket and has a low density filter for filtering large-sized contaminants .

Brief Description of the Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a schematic perspective view showing a typical cage rack system for breeding experimental animals; Fig. 2 is a perspective view showing one of conventional experimental animal breeding cage systems installed in the cage rack system of Fig. 1;

Fig. 3 is a partially exploded perspective view showing the experimental animal breeding cage system of Fig. 2;

Fig. 4 is a front view showing the cage system shown in Fig. 2;

Fig. 5 is a side view showing the cage system shown in Fig. 2; Fig. 6 is a sectional view showing a structure for seating and connecting a water canister in the cage system shown in Fig. 2;

Fig. 7 is a sectional view showing a structure for seating and connecting a feed canister in the cage system shown in Fig. 2;

Fig. 8 is a perspective view showing a cage system according to an embodiment of the present invention; Fig. 9 is an exploded perspective view showing the cage system shown in Fig. 8;

Fig. 10 is a cross sectional view showing a cage lid of the cage system, on which the water canister is mounted; Fig. 11 is a partial cross sectional view taken along line A-A of Fig. 9;

Fig. 12 is a perspective view showing a clamp of the cage system according to the present invention;

Fig. 13 is a partially enlarged view of part "B" of Fig. 10;

Fig. 14 is a cross sectional view showing an air inlet unit of the cage system according to the present invention;

Figs. 15a and 15b are a front view and a side view showing a protecting cap of the cage system of the present invention, respectively;

Fig. 16 is an exploded perspective view of the cage outlet filter of the cage system of the present invention; and Fig. 17a and 17b show a rotating plate of a cage lid filter included in the cage system according to the present invention in a plan view and a cross sectional view taken along line A-A of Fig. 17a, respectively.

Detailed description of the Invention

The application of the preferred embodiments of the present invention is best understood with reference to the accompanying drawings, wherein like reference numerals are used for like and corresponding parts, respectively. As depicted in Fig. 1, five or six experimental animals, for example, mice are bred in an experimental animal breeding cage system 1 of the present invention. The experimental animal breeding cage system 1 is utilized while being disposed in a cage rack system 10 capable of accommodating several cage systems therein. However, each experimental animal breeding cage system 1 of the present invention may be utilized alone, while not being disposed in the cage rack system 10. When the experimental animal breeding cage system 1 of the present invention is mounted in the cage rack system 10 and air-conditioned in a forced air circulation manner, aseptic, fresh air is supplied by the air supply means 11 having air supply nozzles 14 from the outside into the cage system 1 and contaminated air is exhausted by an air exhaust means 18 having air exhaust nozzles 15 from the cage system 1 to the outside. However, when equipped with a cage lid filter 109, as will be described later, the cage system 1 can be separately utilized without being mounted in the cage rack system 10.

With reference to Figs. 8 and 9, there is shown an experimental animal breeding cage system 100 according to an embodiment of the present invention in a perspective view and in an exploded perspective view, respectively. As shown in the drawings, the experimental animal breeding cage system 100 of the present invention comprises a box-shaped container 102 on the rear of which an air inlet unit 140 and an air outlet unit 150 are formed for supplying air to and exhausting air out of the container 102, respectively, when the cage system 100 is used depending on the cage rack system 10, and a cage lid 104 that is engaged with the open top of the container 102 to form a sealed housing and, on which a water canister 120 and a feed canister 130 are detachably mounted.

A pair of position-fixing guides 103a and 103b are formed at opposite sides of the container 102. When the cage system 100 is disposed in the cage rack system 10, the position-fixing guides 103a and 103b are engaged with a pair of position-fixing brackets (not shown) formed in a frame of the rack system 10 to fix the position of the cage system 100 in the rack system 10. The cage lid 104 comprises a water canister- receiving depression 105 for mounting the water canister 120 on the container 100 at one half portion of a front region of the cage lid 104, a feed canister-receiving depression 107 for mounting the feed canister 130 on the container 102 at the other half portion of the front region, and a cage lid filter 109 at a rear region of the cage lid 104, through which air is filtered when air goes into and out of the container 102 with the air inlet unit 140 and the air outlet unit 150 closed, thereby enabling the cage system 100 to be used independently of the cage rack system 10.

In order to prevent the entrance of air through the feed canister-receiving depression 107 which is formed in a rectangular shape on the cage lid 104, a feed canister-receiving depression lid 108 with a shape corresponding to that of the depression 107 is provided.

The feed canister-receiving depression 107 of the cage lid 104 is provided at a circumference thereof with an upwardly protruded flange 111 with which the feed canister-receiving depression lid 108 is engaged. In addition, as will be stated later, flanges 112 and 113 for supporting the feed canister 130 are extended from the lower portions of the front and rear sides of the feed canister-receiving depression 107, respectively. The feed canister 130, made of stainless steel, as shown in Fig. 9, consists of two side plates, each increasingly narrowing from the top to the bottom, a plurality of longitudinal wires 133 which are bent in the same form as those of the side plates, a plurality of transverse wires 134 for fixing the longitudinal wires 133 at regular intervals, and fixing flanges 135 and 136 extended from the tops of the feed canister. The longitudinal wires 133 are disposed at such regular intervals as to form feed exhaust slots 137 which are somewhat smaller than the grains of the feed supplied. That is, as long as experimental animals do not compulsorily pull out intact grains, the slots do not allow them to fall into the interior of the cage system 100. Thus, the experimental animals admitted to the cage system 10 can gnaw the feed partially protruded through the feed exhaust slots 137. When the feed becomes smaller than the slots as the experimental animals gnaw the feed suspended from the wires, it falls into the interior of the container 102. The feed canister 130 is mounted on the cage system 100 in such a way that the fixing flanges 135 and 136 of the feed canister 130 are supported by the supporting flanges 112 and 113 formed at the lower portions of the front and rear sides of the feed canister-receiving depression 107 which is perfectly sealed by putting on the lid 108 while the upwardly projected flanges 111 of the depression 107 are engaged with the lid 108.

Referring to Fig. 10, there is shown a section of the cage lid 104 on which the water canister 120 is mounted. As for the water canister 120, as shown in Fig. 10, it consists of a tank 123 with an opening 121, a nozzle 125 through which water is drawn by the suction of the experimental animals, a hole 126 into which the nozzle 125 is inserted, and a sealing plug 127 fitted into the opening 121. A first inclined wall of the tank 123 on which the opening 121 is formed stands at an angle of 30-50 degrees and preferably at an angle of 40 degrees to a horizontal upper wall of the tank 123. The water canister-receiving depression 105 of the cage lid 104, as shown in Fig. 10, has a second inclined wall which, when the water canister 120 is mounted in the water canister-receiving depression 105, stands at the angle corresponding to that of the first inclined wall of the tank 123 on which the opening 121 is formed. To the second inclined wall is provided an airtight connecting means 129 for airtightly supporting the nozzle 125 of the water canister 120.

Therefore, the hole 126 of the sealing plug 127 connected to the opening 121 formed on the first inclined wall of the tank 123 is positioned at the corresponding angle. This inclination is also found in the nozzle 125 inserted into the hole 126 and in the airtight connecting means 129 of the water canister- receiving depression 105, so that the nozzle 125 is positioned at the angle in the interior of the housing when the water canister 120 is mounted in the depression 105. Accordingly, the structure of the water canister 120 allows the experimental animals bred in the cage system 100 to hold their heads a little to drink water, therefore minimizing the stress which is given to the experimental animals during the ingestion of water. Functioning as a medium through which the tank 123 containing water communicates with the water canister nozzle 53, the sealing plug 127 made of silicon is in an airtight relation with the tank 123, thereby preventing a leakage of water through the water canister nozzle 125 while the experimental animals do not drink water.

A protector 115 formed of stainless steel is fixedly attached to the lower surface of the water canister-receiving depression 105 so as to prevent the lower portion of the depression 105, in which the water canister 120 is accommodated, from being damaged by experimental animals. Referring to Fig. 11, a partial section view, taken along line A-A' of Fig. 9, partially shows the circumference of the upper end of the container 104. As shown in the drawings, a packing groove 141 is formed along the circumference of the upper end of the container 102 so as to accomplish an airtight connection between the container 102 and the cage lid 104. Into the packing groove 141 is fitted a packing member 145 for maintaining the airtight conditions. The packing member 145 has a plurality of connecting projections 147 which extend downwardly. A plurality of connecting holes 143 are formed at the positions corresponding to those of the connecting projections 147. In ^'more detail, the connecting projections 147 of the packing member 145 are narrow in their necks and wide in their heads while the connecting hole 143 is smaller in the size than the heads of the connecting projections 147 but larger in the size than the necks. Accordingly, only the insertion does not suffice the mounting of the packing member 145 on the packing groove 141. The connecting projections 147 are fitted into the corresponding connecting holes 143 in such a way that the heads of the connecting projections 147 completely pass through the connecting holes 143 to form a locking structure which is hard to unlock without intention. Returning to Fig. 9, a pair of clamps 160 are mounted on the front and rear sides of the container 102 to firmly lock the cage lid 104 to the container 102. Fig. 12 shows one of the two clamps 160 in a perspective view. As seen in Figs. 9 and 12, the clamp 160 comprises a knob member 161 whose upper portion is engaged with the container 102 by a hinge, and a locking member 165 whose lower portion is engaged with the middle portion of the knob member 161 by a hinge and which has, at an upper portion thereof, a locking groove 163 that is brought into contact with the external circumference of the cage lid 104 when the clamps 160 are applied to the cage lid 104. With reference to Fig. 13, an end portion of the cage lid 104 is shown in an enlarged view. As shown, a plurality of fixing projections 167 are provided at the external circumference of the cage lid 104, making more reliable the engagement of the container 102 with the cage lid 104. In this structure, it is impossible for the clamp 160 to perform its function when the fixing projections 167 are not accurately inserted into the locking grooves 163. Therefore, there is no possibility that the experimental animals bred in the cage system 100 are exposed to unfiltered air while the cage lid 104 is engaged with the container 102 by the clamps 160. Besides, the fixing projections 167, which are formed over the entire external circumference of the cage lid 104 as well as in the central portion of the front and rear ends of the cage lid 104 engaged with the locking grooves 163 of the clamps 160, play a role in preventing a distortion of the cage lid 104, in combination with deformation-preventing reinforcements 195 as will be described later.

On the external circumference of the cage lid 104, as shown in Fig. 8 and 9, a plurality of reinforcements 195 are provided. Thanks to the presence of the reinforcements 195, the cage lid 104 is prevented from being undesirably deformed, e.g. distorted upon autoclaving.

Referring to Fig. 14, there is shown a cross section of the air inlet unit 140. The air inlet unit 140 and the air outlet unit 150 are similar in their sealing structures. In each of the units 140 and 150, a first bracket 151 provided at its central depressed portion with a first center hole 151a at the periphery of which a plurality of air inlets 151b are formed, is interlocked in an airtight manner with a second bracket 153 provided with a second center hole 153a, through a hole formed in the rear of the container 102 while the circumferential portions of the first and the second bracket are sealed.

A moving member 157, partially inserted into the center hole 151a while being supported by an elastic spring 94 and provided with a third center hole 157a connecting to the first center hole 151a and with a plurality of air inlets 157b at the periphery of the third center hole 157a, is elastically supported in the depressed portion of the first bracket 151. While being geared with the moving member 157, a sealing plate 158 is brought into close contact with the inner surface of the depressed portion of the first bracket 151 so as to close or open the air inlets 151b of the first bracket 151. In the central portion of the sealing plate 158 is formed a stem 158a which passes through the third center hole 157a and protrudes outside. The stem 158a is fixed by a nut 158b and engaged with the moving member 157. In addition, a sealing ring 159 is attached to the contact surface of the sealing plate 158, that is, the surface which is in contact with the first bracket 151 so as to further improve the airtightness, thereby almost completely blocking the inflow and leakage of air through the air inlet unit 140 and the air outlet unit 150 to enable the cage system 100 to be used independently of the rack system.

Unlike the air outlet unit 150, the sealing plate 158 of the air inlet unit 140 through which external air is introduced is provided with an extended circumference 158c at which a plurality of holes 158d are formed. Thus, air can be introduced from the air supply nozzle at a slow rate and widely distributed in the housing, thereby eliminating stress that may be exerted on experimental animals when the air is directed onto the experimental animals.

On the rear side of the container 102, the air inlet unit 140 and the air outlet unit 150 are, as described above, diagonally positioned to maximize the distance between them, so that fresh air supplied from the air inlet unit 140 is uniformly circulated through the interior of the cage system 100 and, thereafter, is discharged to the outside through the air outlet unit 150, thereby allowing all experimental animals to be exposed to fresh air. When the cage system 100 is mounted in the cage rack system 10, the elastic spring 155 is compressed by the pushing of both the air supply nozzle and the air exhaust nozzle. Accordingly, the moving member 157 is brought into contact with the depressed portion of the first bracket 151 and, simultaneously, the sealing plate 102 is moved into the interior of the container 102, thereby breaking the seal. As a result, the air supply nozzle 14 and the air exhaust nozzle 15 of the rack system 10 communicate with the interior of the cage system 100 through a plurality of air inlet holes 157b formed on the moving member 157 and a plurality of air inlet holes 151b formed on the first bracket 151, so air is supplied into and discharged out of the interior of the cage system 100.

Positioned at a lower portion of the rear side of the container 102, the air inlet unit 140 may directly contact with the experimental animals. A protecting cap 170 is additionally provided to the inner side of the air inlet unit 140, as depicted in Fig. 15, with the aim of preventing the noise generation attributable to the contact of the experimental animals with the air inlet unit 140 and of averting the air flow interruption attributable to the insertion of the bedding spread on the bottom of the container 102 into the air inlet unit 140. The protecting cap 170 is provided on its circumferential surface with connecting slits 171 which are designed to interlock with fixing projections (not shown) of the first bracket 151 when the fixing projections are inserted into the connecting slits 171 and rotated. The protecting cap 170 is also provided with a plurality of vent holes 173.

Turning now to Fig. 16, there is shown a cage outlet filter 180 in an exploded view. Like the air inlet unit 140, the air outlet unit 150, as shown in Fig. 16, is provided at its inner side with a cage outlet filter 180. On the first bracket 151 of the air outlet unit 150, fixing projections (not shown) are formed for interlocking with the cage outlet filter 180. The cage outlet filter 180, which is detachably mounted on the first bracket 151 of the air outlet unit 150, is comprised of a filter container lid 183 provided through it with a plurality of vent holes 181 and on its circumferential surface with a plurality of connecting slits 182, a low density filter 185 for filtering large- sized contaminants, and a filter container 188 provided on the circumferential surface of its front portion with connecting projections 186 to be interlocked with the connecting slits 182 of the filter container lid 183 and on the circumferential surface of its rear portion with a fixing recess 187 to be interlocked with the fixing projection (not shown) of the first bracket 151.

As described above, since the air outlet unit 140 includes the cage outlet filter 180, large-sized particles, such as dust from the bedding spread to provide comfort to the experimental animals and to reduce stress caused by the excrements of the experimental animals or fur removed from the experimental animals, can be primarily filtered by the low density filter 185. Accordingly, it is possible to prevent problems in that exhausted impurities stop the air exhaust nozzle 15 of the rack system 10 and are stacked in the tube communicating with the air exhaust nozzle 15. It is preferred that the air inlet unit 140 and the air outlet unit 150 are diagonally positioned to maximize the distance between them. In this case, fresh air supplied from the air inlet unit 140 is uniformly circulated through the interior of the cage system 100 and, thereafter, is discharged to the outside through the air outlet unit 150, thereby allowing all experimental animals to desirably breathe fresh air.

Meanwhile, the cage lid filter 109 is provided to a portion of the cage lid 104 in the experimental animal breeding cage system 100 of the present invention. Accordingly, the cage lid filter 109 is used to filter the fresh air which is being supplied to the interior of the cage system 100 and the contaminated air which is being exhausted out of the interior in the case where the cage system 100 is transported with the experimental animals being bred therein, or separately used without being mounted in the rack system 10.

To this end, the cage lid filter 109 is fitted into a cylindrical flange 193 that is vertically extended from the cage lid 104. The cage lid filter 109, as shown in Fig. 9, is comprised of an openable cap 190 detachably attached to the upper end of the cylindrical flange 193 as to open the cage system 100 in use or as to close the cage system 100 which is not in use, a filter 196 for filtering off contaminants, a fixed plate 198 for supporting the filter 196, attached to the lower end of the cylindrical flange 193 on which a plurality of vent holes are formed, and a rotating plate 199, positioned on the upper portion of the fixed plate 198 to fix the filter 196 onto the fixed plate 198 and to prevent air from entering through the edge of the flange 193 without filtration. Figs. 17a and 17b show the rotating plate 199 of the cage lid filter 109 in a plan view and a cross sectional view, respectively. The cylindrical flange 193 is provided on its inner surface with three locking grooves 194 of a depressed shape for fixing the rotating plate 199 and at its inner circumferential edge with an inner circumferential rim 191, extended from the lower end to the center, for supporting the filter 196. The rotating plate 199 is provided on its circumferential surface at regular intervals with three locking projections 200 for engaging with the locking grooves and at its lower circumferential portion between the inner circumferential rim 191 and the filter 196 with a sealing rim 201, slightly projected downwards, for preventing air from entering through the edge of the filter 196 without filtration. In addition, the rotating plate 199 is also provided with a handle 202 for handling the rotating plate 196.

In order to prevent the deformation of the cage system 100 upon autoclaving, the container 102, the cage lid 104 and the tank 123 of the water canister 120 are preferably formed of polysulphone. The components of the cage system 100 may be formed of polycarbonate, but may be deformed during the autoclaving executed at 120 °C under high pressure because polycarbonate has a thermal deformation temperature of about 135 °C. In contrast, polysulphone is thermally deformed at about 174 °C, as well as being superior in durability and chemical resistance to polycarbonate. Alternatively, polyetherimide may be employed because of its excellent thermal resistance, strength, durability and chemical resistance. The cage system 100 of the present invention can be used to breed not only mice, but rats and rabbits by increasing the size of the cage system 100 according to the size of the experimental animal.

Meanwhile, a label holder is attached to the front of the cage lid 104 to hold a label on which data, such as the name of experimental animals, the dates of experiments, etc., are recorded. In such a case, a user can record the name of an experiment performed on the experimental animals contained in the cage system 100 on the label held in the label holder, so the user can easily follows the experiments that the experimental animals undergo. Additionally, after experiments are performed on experimental animals while the cage system 100 is removed from the cage rack system 10, a user can easily get data concerning the experimental animals.

Industrial Applicability

As described above, a cage system is provided for breeding experimental animals, which has a perfectly airtight structure that is adapted to airtightly and detachably mount a feed canister and a water canister on the cage system and supply feed and water to the feed canister and the water canister, respectively, without opening its cage lid, so that not only can the air contaminated in the interior of the cage system be prevented from leaking, but also external contaminants can be averted from entering the interior of the cage system. When being bred in the cage system, therefore, experimental animals are safe from disease due to contaminated air even in a laboratory without a clean room. Additionally, the cage system enjoys the advantage of being simple in structure and being freely moved thanks to its perfect airtightness.

Moreover, the cage system is less stressful for the experimental animals than conventional cage systems. Therefore, more reliable experiment data can be obtained from the animals. Furthermore, the cage system is not deformed by autoclaving, in addition to being convenient for a user to handle.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

What is Claimed is :

1. A cage system for breeding experimental animals, comprising: a water canister comprising a tank provided with an opening; a nozzle through which water is exhausted by the suction of the experimental animals; and a sealing member tightly fitted into the opening and provided with an insertion hole into which the nozzle is inserted; a feed canister provided with a plurality of feed exhaust slots at regular intervals; a housing comprising a container for accommodating the experimental animals; and a cage lid on which a water canister-receiving depression and a feed canister- receiving depression are formed; a feed canister-receiving depression lid for blocking air from entering through the feed canister- receiving depression; and a pair of clamps, formed on front and rear sides of the container, for locking the cage lid to the container.

2. The cage system as defined in claim 1, wherein the feed canister-receiving depression is provided at its circumstance with an upwardly protruded flange with which the feed canister-receiving depression lid is engaged.

3. The cage system as defined in claim 2, wherein the feed canister is provided with a fixing flange extending from the upper circumference of the feed canister, and the feed canister-receiving depression is provided on its inner circumferential surface with a support flange for supporting the fixing flange.

4. The cage system as defined in claim 3, wherein the tank has a first inclined wall on which the opening is formed, and the water canister-receiving depression has a second inclined wall standing at an angle corresponding to that of the first inclined wall of the tank and is provided on the second inclined wall with" an airtight connecting means for airtightly supporting the nozzle of the water canister.

5. The cage system as defined in claim 4, wherein the first inclined wall of the tank stands at an angle of 30-50 degrees.

6. The cage system as defined in claim 1 or 5, wherein each of the clamps comprises a knob member whose upper portion is engaged with the container by a hinge, and a locking member whose lower portion is engaged with a middle portion of the knob member by another hinge and which has, at an upper portion thereof, a locking groove that is brought into contact with the external circumference of the cage lid when the clamps are applied to the cage lid, and the cage lid is provided with at its external circumference with a fixing projection which is interlocked with the locking groove.

7. The cage system as defined in claim 6, further comprising: a packing member provided with a plurality of connecting projections which are extended downwardly to airtightly engage the container with the cage lid; and a packing groove on which the packing member is mounted and which is formed on the upper circumference of the container and provided with a plurality of connecting holes at positions corresponding to those of the connecting projections.

8. The cage system as defined in claim 1 or 7, further comprising: an air inlet unit, formed on a rear side of the container, for supplying air to the interior of the housing, and an air outlet unit, formed on the rear side of the container, for exhausting air out of the housing, each of the air inlet and outlet units being fitted into a hole formed on the rear side of the container, and comprising: a first bracket which is provided at its central depressed portion with a first center hole, at a periphery of which a plurality of air inlets are formed; a second bracket, having a second center hole at its center, interlocked with the first bracket through the hole with circumferential portions of the first and second brackets being sealed; a moving member, whose circumferential portion is elastically supported in the depressed portion of the first bracket by a spring and which is provided with a third center hole communicating with the first center hole and with a plurality of air inlets at the periphery of the third center hole; a sealing plate, in close contact with an inner surface of the depressed portion of the first bracket while being geared with the moving member so as to close or open the air inlets of the first bracket; and a sealing ring attached to the contact surface of the sealing plate.

9. The cage system as defined in claim 8, .wherein the air inlet unit comprises a protecting cap, provided in the inner side of the first bracket, for preventing generation of noise attributed to the contact with the experimental animals with the air inlet unit and averting impurities from being inserted into the air inlet unit.

10. The cage system as defined in claim 9, wherein the air outlet unit comprises a cage outlet filter which is detachably mounted on the first bracket and has a low density filter for filtering large-sized contaminants.

11. The cage system as defined in claim 10, wherein the cage lid is provided with a vertically extended cylindrical flange and the cage lid filter comprises an openable cap detachably attached to the upper end of the cylindrical flange; a vent fixed plate attached to the lower end of the cylindrical flange; a filter positioned on the vent fixed plate; and a rotating plate whose circumferential portion is so closely attached to the filter as to prevent air from entering without filtration.

12. A cage system, comprising: a water canister comprising: a tank provided with an opening at a first inclined wall thereof; a nozzle through which water is exhausted by the suction of the experimental animals; and a sealing member tightly fitted into the opening and provided with an insertion hole into which the nozzle is inserted; a feed canister provided with a plurality of feed exhaust slots at regular intervals and with a fixing flange extended from the upper circumference; a container for accommodating experimental animals, on a rear side of which an air inlet unit for supplying air into the container and an air outlet unit for exhausting contaminated air out of the container are formed; a cage lid comprising: a water canister-receiving depression provided with a second inclined wall standing at an angle corresponding to that of the first inclined wall of the tank and provided on the first inclined wall with an airtight connecting means for airtightly supporting the nozzle of the water canister; a feed canister-receiving depression provided at the inner circumference with a rim for supporting the fixing flange of the feed canister and at the circumference with an upwardly protruded flange; and a plurality of locking projections formed on the^' front and rear circumferences of the cage lid; a housing comprising a packing member provided with a plurality of connecting projections which are extended downwardly to airtightly engage the container with the cage lid; a feed canister-receiving depression lid, engaged with the flange of the feed canister-receiving depression, for blocking air from entering through the feed canister-receiving depression; and a pair of clamps, each comprising a knob member whose upper portion is engaged with the container by a hinge, and a locking member whose lower portion is engaged with the middle portion of the knob member by another hinge and which has, at an upper portion thereof, a locking groove that is brought into contact with the external circumference of the cage lid when the clamps are applied to the cage lid; and a cage lid filter comprising a filter through which air passes into and out of the housing.

13. A cage system for breeding experimental animals, comprising a cage lid provided with first and second depressions for mounting a feed canister and a water canister thereon, and a container for accommodating the experimental animals, the cage system comprising: a lid to cover the first opening so as to prevent the entering of contaminants through the first opening into the container.

14. The cage system as defined in claim 13, wherein the water canister comprises a nozzle through which water is discharged by the suction of the experimental animals, said nozzle being positioned to be inclined.