Patent Application
20090120853
The present invention relates in general to a fish tank, either portable or installed in a boat as a livewell, for keeping fish or bait alive in a healthy condition and, more specifically, to a portable fish tank or a livewell that provides an artificial current in the water for species of fish that require continuous movement to keep them in a healthier and less stressed environment.
In order to maintain species of fish that require continuous movement through the water, an artificial current must be provided in portable tanks or livewells to ensure their survival. Fast swimming fish will school in the current along the perimeter of the tank. The size of the fish that can be maintained is limited by the diameter of the tank. Larger fish would need an extremely large tank to ensure that they can swim without their bodies being continuously curved and causing them damage. These types of tanks are not only stressful for the fish, but cumbersome, and take up valuable deck space for passengers, increase the weight of the boat, and may also cause safety hazards.
Japanese Patent Application JP 59-167396 A discloses a live-fish tank 2 in a fishing boat in which a water jet pipe 3 is provided in a position slightly higher than the bottom face of the live-fish tank having a hatch 4 at the center of its ceiling. A number of jet holes, which jet out water deflected from the center of the tank 2 are provided on the jet pipe. By jetting out sea water, a whirling stream A is generated in the upper part of the tank 2 for live fish to swim in (see
The object of the invention is therefore to overcome the above-mentioned drawbacks of the prior art live-fish tanks and to provide a fish tank, either portable or installed in a boat as a livewell, that (a) will provide an environment to allow small or large fish to swim in a more natural state, and (b) is smaller and lighter than the conventional bait and fish tanks, and thus save deck space and reduce the weight added to the boat.
The above object is achieved by producing continuous water movement in one direction in a long and narrow rectangular tank. The tank includes an inner container for fish to swim in and an outer container for facilitating water circulation. The water enters the inner container at one end through an entry hole and exits the inner container into the outer container at the other end of the inner container through an exit hole, and then returns to the entry hole back into the inner container. This creates an endless stream in the inner container. During the circulation of the water, it can also provide aeration required for fish within the inner container. This tank simulates a more natural movement of water for fish survival. The fish will swim upstream and in one direction. Water speeds may be adjusted according to the swimming speeds of the species of fish contained in the inner container by a pump installed in the outer container.
The endless stream fish tank or livewell according to the invention has the advantage that it requires less space than the conventional large round, oval or square tanks or livewells. It is long and narrow and can be placed alongside the gunwales of a boat allowing more passenger space.
The inner container of fish tank is designed to ensure a continuous stream of water with minimal eddies of water. The bottom of the inner container and/or the outer container of the tank can have a semi-circular shape to further reduce the size and weight of the tank by reducing the amount of water needed. The side walls of the outer container can be formed in corrugated shape to increase tank stability and reduce weight.
The fish tank or livewell according to the concept of the present invention can also be designed as a double tank configuration with each tank having a similar structure to the inner container of the single tank configuration as described above. The pump(s) may be installed between the two single tanks. In one embodiment, aeration can occur by metering gasses between two pumps. Air or pure oxygen can be inserted by either venturi or pressure. The downstream pump will allow continuous pressure to the upstream pump. This will allow maximum gasses to mix with the upstream pump without any deterioration of pump pressure in the line. This is required for fish that require continuous fast movement through the water.
If a slower moving fish needs to be maintained within the tank, the downstream pump can be bypassed. Metering of gases will occur between the pumps, or downstream of the upstream pump. Metering of gases downstream of the upstream pump will allow the speed of the upstream pump to be variable while maintaining water aeration. Water speed can be slowed almost to the point where the pump will start to cavitate in order to accommodate slower swimming species.
Both the single tank and double tank designs of the invention can be utilized as a portable fish tank or in permanent boat installations. The livewell can be a simple design, and plumbing can be hidden under the boat decking.
The single tank configuration allows all water flows required to be within the tank, and thus reduces plumbing requirements and hazards.
There are shown in the drawings, embodiments which are presently preferred. It is expressly noted, however, that the invention is not limited to the precise arrangements and instrumentalities shown.
The inner container 30 has a first end 31 and a second end 33. An entry hole 32 is formed in the first end 31 and an exit hole 34 is formed in the second end 33. The water enters the inner container 30 at the first end 31 through the entry hole 32 and exits the inner container 30 into the outer container 40 at the second end 33 of the inner container 30 through the exit hole 34. After passing through the space between the inner and outer containers 30, 40, the water then returns to the entry hole 32 and back into the inner container 30. This creates an endless stream in a straight direction in the inner container 30 for fish to swim against. The water circulation direction is shown in the diagram of
The inner container 30 of the fish tank 100 is designed to ensure a continuous stream of water with minimal eddies of water. The bottom of the inner container and/or the outer container of the tank can have a semi-circular shape to further reduce the size and weight of the tank by reducing the amount of water needed (see
If slower moving fish needs to be maintained within the tank, the downstream pump 120′ can be bypassed. Metering of gases will occur between the pumps, or downstream of the upstream pump. Metering of gases downstream of the upstream pump will allow the speed of the upstream pump to be variable while maintaining water aeration. Water speed can be slowed almost to the point where the pump will start to cavitate in order to accommodate slower swimming species.
All variations of the endless stream tanks, including portable single tanks, portable double tanks, and permanently installed boat livewells can utilize a raw water entry at the inlet of the tank with an overboard discharge 170 (see
The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are also merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.
