| 摘要 |
The invention relates to a multistage membrane distillation device comprising a heating stage (28), preferably multiple condensing/evaporating stages (12), and a condensing stage (36) through which a liquid to be concentrated is passed in succession. Each condensing/evaporating stage comprises at least one condensing unit (K) and at least one evaporating unit (V). Each condensing unit comprises a first steam chamber that is delimited at least partly by a condensation wall (16), and each evaporating unit comprises a second steam chamber that is delimited at least partly by a steam-permeable liquid-tight membrane wall (20). At least one flow channel which is formed between such a condensing unit K and such an evaporating unit V that adjoins said condensing unit and which conducts the liquid to be concentrated is provided in each condensing/evaporating stage so that the liquid to be concentrated is heated by means of the condensation wall, and the steam that is generated from the liquid to be concentrated reaches the second steam chamber through the membrane wall. The steam that is produced in a respective preceding stage is conducted into a condensing unit of the immediately following stage via a steam channel which exclusively conducts said steam and which exclusively further conducts said steam to the immediately following stage. |
