Abstract:
An aquatic housing system that has a frame that defines two or more housing levels. Each housing level has a plurality of tanks for housing aquatic animals. Each tank has a front mounted plumbing assembly that allows both water overflow and drainage to be conveyed away from the tank. A valve located in the drainage connection allows the tanks to be flushed or converted from a deep water animal to a shallow water animal without removing the tank from the frame.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a system for housing animals and, in particular, to an aquatic housing system for aquatic animals, such as fish, frogs and the like. 
     2. Description of the Prior Art 
     Aquatic housing systems are useful for breeding, feeding and maintaining aquatic animals. Aquatic housing systems have found particular use in the fields of developmental biology, pharmacology and medical research. 
     Aquatic housing systems generally have a rack construction that allows for several rows or levels of individual housing tanks to be stacked vertically. A water supply provides water to the tanks and a drainage assembly captures overflow water that exits an aperture near the top of the tank. An example of a known aquatic housing system is shown in U.S. patent application, Ser. No. 09/204,040, filed on Dec. 1, 1998 for Aquatic Housing System and assigned to the Assignee of this application. 
     A system for housing fish is currently available from Marine Biotech, Inc. of Beverly, Mass. This system has a rack construction that allows for several levels or rows of fish tanks to be stacked vertically. Each level has a tank shelf that serves a twofold purpose. First, it serves as a shelf to hold a row of fish tanks. Second it serves as drainage for water that empties, spills, splashes or overflows from the tanks. The shelf slopes downward to the back of the rack where a vertical waste column is formed along the entire width of the rack. A water manifold provides water to the tanks. 
     A system for housing frogs is also available from Marine Biotech, Inc. of Beverly, Mass. This system provides for overflow drainage via overflow apertures near the tops of the tanks. Only one species of frogs can be housed in this system at one time. 
     The aforementioned aquatic systems provide for drainage of water that overflows the tank. The tank must be removed for rinsing or flushing. 
     When frogs inhabit aquatic tanks, unconsumed food and other waste accumulate rapidly. Thus, there is a need for frequent cleaning by rinsing or flushing of tanks inhabited by frogs. The aforementioned aquatic housing systems utilize a circulating water system whereby overflow water is filtered and reused. When there is a lot of waste, filters tend to clog and need frequent replacement. Delay in replacing filters can result in harmful disease organisms remaining in the tanks that seriously affect the health of aquatic animals, such as frogs. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an aquatic housing system that allows in situ flushing of the tanks. 
     Another object of the present invention is to provide an aquatic housing system that provides for both overflow and drainage from an aquatic tank. 
     Still another object of the present invention is to provide an aquatic housing system with gravity assisted drainage and waste removal. 
     An aquatic housing system according to the present invention includes one or more aquatic tanks disposed on a tank frame. A water distributor provides continuous flow of water to the tanks. A drainage plumbing assembly is coupled with the tank and positioned to capture water overflow from the tank and is selectively operable to drain water from the tank. 
     The tank has an overflow orifice near its top and a drain orifice near its bottom that are coupled with the drainage plumbing assembly. The tank and/or frame are dimensioned so that the tank bottom slopes downwardly at a small angle to the horizontal to provide gravity assisted removal of waste from the tank via the drainage plumbing assembly. 
     The tanks are substantially opaque so that the vision of a frog housed within one of the tanks is limited to the tank. 
     In another embodiment of the invention, a drainage plumbing assembly is coupled with the tank and is selectively operable to drain water from the tank. The frame and/or tank is dimensioned so that the tank bottom slopes downwardly at a small angle to the horizontal to provide gravity assisted removal of waste from the tank via the drainage plumbing assembly. 
     In a further embodiment, an aquatic tank has a top, a bottom and at least one side wall. An overflow orifice located in the side wall near the top and a drainage orifice is located in the side wall near the bottom. A drainage plumbing assembly is connected to the overflow orifice and to the drainage orifice for receiving water overflow via the overflow orifice and drainage water via the drainage orifice. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Other and further objects, advantages and features of the present invention will be understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference characters denote like elements of structure and: 
     FIG. 1 is an elevational view of an aquatic housing system according to the present invention; 
     FIG. 2 is a front elevation view of the rack of the FIG. 1 aquatic housing system; 
     FIG. 3 is a side view of FIG. 2; 
     FIG. 4 is a cross-sectional view taken along line  4 — 4  of FIG. 1; and 
     FIG. 5 is an end view of the rack. 
    
    
     DESCRIPTION OF THE INVENTION 
     With reference to FIGS. 1 through 5, there is provided an aquatic housing system generally represented by numeral  20 . Aquatic housing system  20  includes a frame or rack  30 , a plurality of housing levels  24 A and  24 B, a plurality of aquatic animal tanks  21 , a water distributor  22 , a drain conveyor or pipe  26  and a plurality of drainage plumbing assemblies  28 . 
     Rack  30  includes front corner posts  31  and  32  and back corner posts  33  and  34 . As best seen in FIGS. 3 through 5, front corner posts  31  and  32  extend to the bottom of housing level  24 A and back corner posts  33  and  34  extend above housing level  24 A. Rack  30  also includes a plurality of side members that connect corner posts  31  and  33  at each housing level  24 A and  24 B. Thus, side members  35  and  36  (FIG. 3) connect front corner post  31  and back corner post  33  and side members  37  and  38  (FIG. 5) connect front corner post  32  and back corner post  34 . Front corner posts  31  and  32  are interconnected by cross members  40  and  42 . Back corner posts  33  and  34  are interconnected by cross members  44 ,  46  and  48 . The connections of these members to the corner posts may be any suitable fasteners, such as bolts. 
     Corner posts  31  through  34 , side members  35  through  38  and cross members  40 ,  42 ,  44 ,  46  and  48  are preferably stainless steel, but may be constructed with fiber glass material. 
     Water distributor  22  has a pipe  52  disposed above housing level  24 A and a pipe  54  disposed above housing level  24 B. Pipes  52  and  54  are joined with a water feed pipe  55  via a tee connector  57 . Pipes  52  and  54  include a plurality of valves  56  located above tanks  21 . Valves  56  are selectively operable to supply water to individual ones of tanks  21 . Referring to FIG. 4, pipes  52  and  54  are supported by rack  30  by means of holders, such as J-bars  58  toward the back of rack of  30 . 
     Drain pipe  26  has a pipe  62  disposed below housing level  24 A and a pipe  64  disposed below housing level  24 B. Pipes  62  and  64  are joined with a drain pipe  66  via a tee  68 . Drain pipe  66  leads to a drain. Referring to FIG. 4, drain pipes  62  and  64  are supported by rack  30  with J-bars  70  at the front of rack  30 . Drain pipes  62  and  64  include a plurality of tee connectors  72  located to the front and below each of tanks  21 . 
     Aquatic animal tanks  21  have a bottom  80  and a top  82  that are joined by at least one side wall, as , for example for a cylindrical geometry. For a preferred embodiment, the tank geometry is box shaped with four sides  84 ,  86 ,  88  and  90 . Top  82  may be completely open for aquatic animals that do not jump, for example, frogs of the Xenopus species such as Xenopus Laveis and Xenopus Tropicalis. Top  82  is partially open enough to admit water from valve  56  for aquatic animals that are capable of jumping, for example frogs of the Rana species, such as Rana Pipiens and Rana Catesbeiana. 
     Xenopus frogs tend to get nervous when humans are in the vicinity of aquatic housing system  20 . Xenopus frogs react by repetitively bumping into the side walls, thereby incurring self-inflicted injury. For this reason, tanks  21  are preferably opaque, when used for Xenopus frogs, to limit the vision of the frogs to the tank. Tanks  21  are preferably constructed of molded polyethylene. 
     Referring to FIGS. 1 and 4, each tank  21  has an overflow orifice  92  located in side wall  84  near top  82  and a drainage orifice  94  located in side wall  84  near bottom  80 . 
     Each drainage plumbing assembly  28  is connected to a different one of tanks  21  to capture water overflow as well as water drainage. Each drainage plumbing assembly  28  includes an overflow connector  102  and a drainage connector  104  that are joined by a tee  106  with a down connector  108 . Overflow connector  102  is coupled to overflow orifice via an overflow fitting  96  and drainage connector  104  is coupled to drainage orifice via a drainage fitting  98 . Down connector  108  is positioned in the upper extension of tee  72 , whereby overflow and drainage water flow through connectors  102 ,  104 , tee  106  and down connector  108  to pipe  62  or  64 , tee  68  and pipe  66  to a drain. Connectors  102 ,  104 ,  106  and  108  may be any suitable plumbing conduit, rigid or flexible. Also, tee  106  can be omitted and connectors  102  and  104  shaped to direct overflow and drainage water directly to drain pipe  62  or  64 . 
     Each drainage plumbing assembly  28  includes a selectively operable valve  110  that is manually operable from a closed position in which water is not drained from tank  21  and an open position in which water is drained from tank  21 . Valves  110  allow tanks  21  to be drained, rinsed or flushed in situ without being removed from rack  30 . Valves  110  may any suitable water valve, such as a single ball valve. 
     Down pipe  108  has a smaller diameter than that of tee  72  so that it merely slips in and out of tee when it is desired to remove a tank  21  from rack  30  for replacement, repair or washing. 
     Referring to FIG. 5, rack  30  and/or tanks  21  are dimensioned so that bottoms  80  of tanks  21  are at a slight angle α to the horizontal. By sloping bottoms  80 , waste that settles on bottoms  80  tends to gravitate toward and localize near the front wall  84  of tank  21 . This facilitates waste removal via drainage orifice  94  when valve  110  is open for a flushing operation. Angle α is preferably in the range of about 3° to 15°, more preferably in the range of about 3° to 10° and is most preferably 5°. As shown in FIGS. 2 through 5, rack  30  is designed so that back cross members  44  and  46  are higher than front cross members  40  and  42 . Side members  35  through  37  slope downwardly by angle α from back corner posts  33  and  34  to front corner posts  31  and  32 . 
     Referring to FIG. 5, a shelf  112 A extending the width of rack  30  rests on back cross member  46  and front cross member  42 . Shelf  112 A has a downwardly extending back lip  114 A that engages cross member  46  so as to prevent shelf  112 A from sliding and maintain it in place. A shelf  112 B extending the width of rack  30  rests on back cross member  44  and front cross member  40 . Shelf  112 B has a downwardly extending back lip  114 B that engages cross member  46  so as to prevent shelf  112 B from sliding and maintain it in place. Tanks  21  rest on shelves  112 A and  112 B. Shelves  112 A and  112 B have upwardly extending front lips  116 A and  116 B, respectively, to keep tanks  21  from sliding off rack  30 . 
     For Xenopus frogs, drainage plumbing assembly  28  is operated with valve  110  closed. Tank  21  will fill to the level of overflow orifice  92 . When this level has been achieved, continued water flow results in an overflow via orifice  92  and drainage plumbing assembly  26  to drain pipe  26 . Such continued water flow allows water in tank  21  to be constantly flushed via overflow orifice  92 . 
     For a flushing operation, valve  110  is opened. Water in tank  21  rapidly drains via drainage orifice  94  to the level of drainage orifice  94 . Continued water flow acts to flush away waste and/or debris. 
     Rana frogs need a shallow water environment. To house Rana frogs, valve  110  is opened. If tank  21  is empty, water fills tank  21  to the level of drainage orifice  94 . If tank  21  is full and valve  110  is opened, water drains via drainage orifice  94  to a level even with drainage orifice  94 . Continued water flow results in water exiting via drainage orifice  94  and drainage plumbing assembly  28  to drain pipe  26 . 
     The location of drainage plumbing assemblies  28  on front wall  84  of tanks  21  enables caretaker control of flushing and change over from housing Xenopus frogs to Rana frogs. 
     The aquatic housing system of the invention allows caretaker control of drainage and tank changeover from one type of aquatic animal to another. The opaque tanks shield caretakers and others from the vision of frogs. Aquatic housing system  20  can be concurrently used for multiple frog species. 
     It will be apparent to those skilled in the art that the size, shape and number of housing levels of rack  30  and the size, shape and number of tanks  21  depend on the needs and specification of the end user. The size of pipe for water distribution and drainage depends on water volume and water flow rate required by the end user. 
     The present invention having been thus described with particular reference to the preferred forms thereof, it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the present invention as defined in the appended claims.