3. DENSITY CURRENT GENERATOR
The prototype machine for generating the density current was researched and made by the authors. 1) 2) The purpose of the machine is to make a density current and agitating the stratified sea water in the enclosed bay very calmly, and prevent the pollution such as the formation of low oxygen water, red tides, water blooms, etc.
Fig.2 shows a conceptual schema and general arrangement of the prototype density current generator. Waters from the surface and bottom layers of the sea are sucked through bell-mouths and vertical pipes, and mixed up by the motor-driven impeller which has blades on both sides of the disc, then the mixed water is discharged horizontally toward all directions within the middle layer from the ring-nozzle formed in the pump casing, whereupon the water spreads through the layer as a density current. The electric power for driving the impeller motor is supplied by solar battery on the supporting pontoon.
The machine has been installed at Hasamaura of Gokasho Bay in Mie Prefecture Japan (about 100 km southward from Nagoya City) since June 1997, and is working continuously for more than 2 years at the point of 15 m water depth shown in Fig.3. This sea area is a enclosed bay with a length of approximately 2km and a width of about 500 m. The total amount of sea water is approximately 12,000,000 m3.
To achieve a turnover of this water during the summer in a period of about 100days, we designed the machine can create a mixed water of approximately 120,000 m3/day.