| 摘要 |
The invention relates to a method for evaporating a solution and an evaporator applied to it. The evaporator ( 1 ) has parallel plate heat exchanger elements ( 3 ) fitted inside a jacket ( 2 ), consisting of a flexible plastic film, for example, and a liquid distribution space ( 4 ) common to the elements, from where the solution to be evaporated can be spread, through supply channels ( 6 ), on the heat transmission surfaces ( 4 ) of the elements to run from the top downwards. The solution ( 10 ) that has not evaporated on the surfaces is recycled from the bottom of the evaporator back to the liquid distribution space, and from there to the heat transmission surfaces ( 4 ) of the elements for re-evaporation. In connection with evaporation, precipitate is separated from the solution as a result of over-saturation, ending up in the recirculation flow with the solution and being separated from the solution in the liquid distribution space ( 14 ) that works as a separator for the precipitate. The recirculation flow is fed into the space ( 14 ) so that the precipitate in it is separated under the effect of its weight and/or kinetic energy, while the flow of the solution is directed upwards, ending up in the supply channels ( 6 ) leading to the heat transmission surfaces ( 4 ) of the elements. The space ( 14 ) can consist of an elongated duct, the flow being fed to its end from a downward curving recirculation line, or the space can consist of a trough, which is provided with lamellas ( 16 ) or a perforated intermediate bottom, which separate the precipitate. |
