GB787706A - High vacuum distillation apparatus - Google Patents

Abstract

In high-vacuum distillation apparatus comprising a vessel 1 through which passes a horizontal rotary shaft 8 carrying spaced discs 11 whose lower segments dip into the distilland in the sump of the vessel, condensing surfaces 12 being disposed between the upper segments of the discs, displacement bodies 25 are provided in the sump-space between the discs in order to reduce the volume of distilland necessary in the sump for maintaining the required minimum immersion of the discs. The vessel is connected to vacuum pumps by pipe 3. In continuous <PICT:0787706/III/1> distillation, the distilland is fed continuously from reservoir 6 through pipe 5 into one end of the sump where it is heated by electric-heater 37. Shaft 8 passes out of the vessel through stuffing-box 10, and is rotated by any suitable drive. Evaporation takes place from the film of distilland on the upper surfaces of the discs. Condensation takes place on condensers 12 which are supplied with cooling medium via pipes 13 and 14. The distillate collects in troughs 15, and is withdrawn via pipes 16, 16a, 16c into one or other of the receivers 18a, 18b. The distillation-residues are withdrawn via pipe 20 into receiver 23, the level of distilland in the sump being adjusted by the height of pipe 20, which can be moved in stuffing-box 21. The displacement bodies 25 may have either transverse bores or groove-like recesses to facilitate the movement of the distilland towards the outlet. In another embodiment, which is very suitable for very heat-sensitive liquids, the rotating discs are hollow, and the distilland is heated by passing heating-medium through them. In this case, the displacement bodies are also hollow, but cooling-medium is circulated through them. Specification 667,285 is referred to.