| 摘要 |
<p>1351519 Fish tanks MARINE PROTEIN INTERNATIONAL CORP 19 April 1971 [5 March 1970] 23347/71 Heading A1A Fish are reared at high density, e.g. over 6 lb/U.S. gallon, in a tank which is continuously supplied with air or oxygen at the bottom to obtain nearly complete saturation, and throughout which the water rises substantially vertically to overflow over the entire periphery of the top of the tank side walls. The water is fed under gravity from a storage tank 18 (Fig. 2 not shown) through the tanks and to a pond in which more fish are reared. Alternatively the water is pumped and the speed varied intermittently. Each tank, Fig. 4, comprises a water space 53 at the bottom of which a conduit 23 discharges from the previous tank and at the top of which water passes through screen 42 into channel 40. The water discharges through outlet 44 and splashes into a cone in the entry funnel 48 of the next conduit 23, the resulting turbulence assisting the loss of carbon dioxide and ammonia to and absorption of oxygen from the atmosphere. The water pours over the edge of the cone into conduit 23 where the flow draws in air through pipe 50. Air or oxygen is pumped into chamber 54 and through porous, e.g. carborundum stone, floor 59 to form bubbles between 0.1mm and 0.5mm diameter in the tank. Alternatively the gas may be pumped through a lattice of nylon mesh tubes. The screen 42 is cleaned with a brush after closing outlet 44 and opening a similar waste outlet so that the dislodged material is washed away. The tanks may be closed over and artificial lighting and temperature control employed.</p> |
