MULTI-LAYERED GASEOUS PHASE CULTIVATION

Abstract: This invention relates to a method of providing three-dimensional mass-cultivation of aquatic organims kept imme­ diately below multi-layered gaseous phases, in which the problem of oxygen supply is solved by fixing a large number of containers in the water and allowing air to stay in multiple layers. When air is supplied from below, it can pass from lower containers to upper containers through hollow tubes and a natural underwater environment can be produced at all points in the water. ABSTRACT The system comprises tray-like shallow vats placed upside down horizontally at intervals in a culture tank so as to pro­ vided air spaces partitioned in mid water. When the gas is sent via an air supply pipe into air space at the bottom, a good number of the artificial environment, being contact with an atmospheric environment as the natural surface of water, is efficiently provided in the culture tank.

Description: The present invention relates to a multi-layered, gaseus phase cultivation method for culturing aquatic organism in water with the features of first part of claim 1. In conventional cultivation tanks for culturing aquatic organisms, such as fish, violent aeration, using water-wheel-like machines or acrators, is applied so as to dissolve atmospheric oxygen into relatively shallow cultivation tanks or ponds. If deeper tanks or ponds are introduced for the purpose of mass culture, the oxygen concentration in the water tends to be insufficient for the growth of the organisms, which results in lower production efficiency. However, the use of shallow and large tanks or ponds decreases land utility efficiency and also aggravates the difficulty in collecting and removing feed debris and excretions, which sometimes results in environmental deterioration of the tanks and ponds. Furthermore, in conventional methods for culturing plant or animal cells or micro-organisms on a large scale, the damaged by aeration devices, such as water-wheel-like machines rotating violently to supply atmospheric oxygen into water. EP-A-0 103 685 discloses a method with the features of the first part of the claim. It is the object of the invention to provide a cultivation method for aquatic organisms which solves the problem of oxygen deficiency of cultivation tanks. This object is solved by the features of the only claim. The present invention will be explained in further detail with reference to the accompanying drawings. Fig. 1 is a sectional view showing an embodiment of the present invention and Fig. 2 is a side view showing another embodiment of the present invention. In Fig. 1, reference numeral 2 represents a culture tank and reference numeral 1 a tray-like shallow vat. A plurality of (four, in Fig. 1) vats 1 are disposed with their open surface facing downward as shown in Fig. 1. These vats 1 are disposed at four levels inside the tanks 2 with predetermined gaps between them by means of a support pole 3 which is located substantially at the centre of the tank 2. Reference numeral 5 represents an air supply pipe. The outlet of this air supply pipe 5 is extended in such a manner as to supply the air to the lower open surface of the vats 1 of the lowermost stage. Reference numeral 7 represents a round vent hole which is bored at part of the upper wall of each vat 1. The vent holes 7 are shown disposed at different positions to one another in the embodiment shown in Fig. 1. Reference numeral 6 represents a cylinder (partition wall) implanted at each vent hole 7 for guiding the air into each vent hole 7. The height of this cylinder 6 is a little lower than the height of the peripheral wall of the vat 1. Next, the function of the present invention having the construction described above will be explained. First of all, when the air is pressure-fed by the air supply pipe 5 via the lower open surface of the vat 1 of the lowermost stage, the gas accumulates in the vat 1 until the water level is at the base of the cylinders 6 of the vat 1 of that stage. When the supply of the air is continued, the air rises up through the vent hole 7 of the cylinder 6 and is again permitted to accumulate in the vats 1 of the next higher stage. When this air supply operation is repeated, the air is caused to accumulate in each space of each vat 1 which is disposed in the four stages. Thus, in accordance with the present invention, the unstable gas existing in water can be allowed to accumulate to the depth of the cylinder 6 and can be controlled accurately. Accordingly, the spaces of the vats 1 become the air zones and at the same time, become suitable cultivation places of aquatic organisms. Accordingly, a large number of air layers and a large number of cultivation places can be disposed inside one culture tank 2. In Fig. 2, for clarity, the air supply pipe, support pole and vent hole are not shown. H-shaped vats are formed as shown in the drawing, and sand grains or fine gravel 8 are put on the open spaces on their upper surface so as to form cultivation areas for aquatic organisms and to accomplish the atmospheric underwater environment which is the same as the environment below the natural water surface.

Claims: A multi-layered, gaseous phase cultivation method for culturing aquatic organism in water, comprising the steps of: disposing a plurality of tray-like shallow vats (1) in a culture tank (2) horizontally and upside down, each of said vats (1) including a substantially horizontal flat portion, a substantially vertical perimeter wall at the perimeter of said flat portion, a hole (7), passing through said flat portion, and a tube (6) surrounding and extending along a central axis of said hole (7); providing a supporter (3) to support said vats (1) in a stack with certain intervals between said vats (1) in such a manner as to divide said culture tank (2) into multiple spaces; feeding air from the bottom of said culture tank (2) to said one of said vats (1) disposed in the lowerst portion of said culture tank (2), via an air supply pipe (5); and reserving said air in an air space (4) in said vats (1) between said flat portion and said perimeter wall, characterized by putting sand grains or fine gravel on at least one surface of each horizontal flat portion so as to form each cultivation place for aquatic organism, and sending the air stored in said air space (4) to the next vat upward through each vat hole (7) in successive vats (1).

Inventors: NOJIMA HISATAKE, NOJIMA YOUKO, NOJIMA, HISATAKE, NOJIMA, YOUKO
Applicants: PARASIGHT YK, YUUGEN KAISHA PARASIGHT
Application year: 1988
Main classification: A01K63
IPC codes: A01K63