| 摘要 |
A pressurised raw water stream is divided by a membrane separation process into a pure water stream and a service water stream. The raw water stream is subject to temporary changes in flow rate. Either the ratio of the flow rate of the pure water stream to the flow rate of the raw water stream is kept at least approximately constant, or a part-stream of constant flow rate is taken off from the raw water stream and divided in such a way that the ratio of the flow rate of the pure water stream to the flow rate of the raw water part-stream is constant. The apparatus for carrying out the first process variant includes an actuator for controlling the flow rate of the pure water stream, which itself can be controlled by the flow rate of the raw water stream. The apparatus for carrying out the second process variant includes a control valve (3) having overflow characteristics. This is installed, parallel to the primary side of the membrane module (4), into the bypass line (2) of the feed line (1) for the raw water stream and the outlet line (1) for the service water stream. The apparatus for carrying out the process can have at least one reservoir for the pure water. <IMAGE> |
