Abstract: A method and apparatus for purifying a fluid are disclosed. An evaporation unit and a condensing unit are employed. Each unit has a chamber and a plurality of spaced-apart fragmentation plates, each plate spanning at least a part of the width of the chamber and each defining the upper limit of an evaporation zone or condensation zone. Each evaporation zone is provided with a fluid vapour outlet and each condensation zone is provided with a fluid vapour inlet. The evaporation and condensation zones operate at different temperatures. The fluid vapour outlet of the evaporation zone operated at the highest temperature is connected to the fluid vapour inlet of the condensation zone operated at the highest temperature, and the fluid vapour outlet of the evaporation zone operated at the lowest temperature is connected to the fluid vapour inlet of the condensation zone operated at the lowest temperature.