| 摘要 |
The vacuum distillation assembly has a flash evaporator, a vapor compressor (12) and a following multi-stage condenser. The condenser has a system to feed back at least part of the condensation from a condensing stage into the bottoms product. Rectifications (14) are between the condensing stages, using two to four stages. The base product is used as a heat carrier fluid for the condenser, before return to the evaporator. The condensation from the final condensation stage is wholly or partially returned to the evaporator, where there are two stages. The condensation is passed back to the base product, to be mixed with it to be fed to the evaporator. The bottoms product is given a forced circulation through the condenser, using a recirculation pump. A pre-vacuum pump is used in addition to the compressor, using a oil-powered fluid pump or a membrane pump (16a, 16b). A system separates solid and/or liquid components from the head product, carried with it during the flash evaporation. An Independent claim is included for a distillation technique where the solution is relaxed under a vacuum, for the head product to be moved onwards as a volume for compression. The head product is condensed in a number of stages, to be divided into heavy and light volatile fractions. At least part of the bottoms product from at least one stage is returned to the vacuum stage until the required concentration is achieved. Preferred Features: When using a binary solution, the process is in two stages, with at least part of the condensation from the second stage returned to the bottoms product. The condensation is returned in a sufficient volume to maintain a constant water:alcohol ratio in the bottoms product. The bottoms product is distilled using the flash evaporation. The concentration is set in a watery ethanol vegetable drug extract with an ethanol content of at least 20 vol% and preferably 30-70 vol%.
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