Patent ID: 7276139

Claim:
A method for concentrating a solution in which a solute is dissolved in a solvent, comprising steps of: generating a solvent gas from said solution in a concentrating tank to concentrate said solution; condensing said solvent gas in said concentrating tank to recover said solvent gas as a condensed solvent, providing said concentrating tank with a tank main body, for containing said solution, and with a roof disposed on said tank main body, providing an inclined inner surface on said roof to form a condensing surface for condensing and recovering said solvent gas, inserting in and concentrating tank at least one flash nozzle, disposing said at least one flash nozzle under a liquid surface of said solution in said concentrating tank so as to discharge a fresh solution into said concentrated solution, and attaching a draining pipe to a bottom of said tank main body for draining said concentrated solution from said concentrating tank.