GB719563A - Improved apparatus for high vacuum distillation - Google Patents

Abstract

High vacuum distillation apparatus comprises a plurality of chambers disposed in series for the continuous gravity flow therethrough of the liquid to be treated, one or more of the chambers being used for degassing the liquid before it is distilled, means for creating in the chambers a vacuum which increases from one chamber to the next in the direction of the flow, means for maintaining the interior of the chambers at temperatures increasing from the first chamber to the last, a rotary member mounted in each chamber to receive the inflowing liquid and project it on to a surrounding wall so that a thin and regular film of liquid flows down the wall, a heated surface positioned in the last chamber to receive the liquid from the relevant surrounding wall, a cooled surface for condensing the vapours disposed close to the heated surface, <PICT:0719563/III/1> and conduits provided with liquid-seals for the continuous withdrawal of distillate and distillation-residue from the last chamber. In the apparatus shown, the liquid is degassed in chambers A1 and A2 which are separated by funnel 5 and liquid seal 6. Discs 9 and 10, rotated by shaft 11, are disposed in chambers A1 and A2 respectively. The cylinders 1, 2, bounding the chambers are heated by passing heating medium through jackets 14, 15; chamber A2 being maintained at a temperature higher than that of chamber A1. Chamber A1 is evacuated via pipe 17 to create a vacuum therein of the order of 1/10 mm. Hg.; and chamber A2 is evacuated via pipe 18 to create a vacuum therein of the order of 1/100 mm. Hg. The liquid enters chamber A1 through pipe 20, and is projected by rotating disc 9 against the internal surface of heated cylinder 1 in the form of a thin film; and is thereby degassed. The liquid then flows through seal 6 into chamber A2 where rotary disc 10 distributes it over the internal surface of cylinder 2. The liquid which collects at the base of chamber A2 is entirely freed of gas. The degassed liquid flows via pipe 22, liquid seal 23 and pipe 24 into distiller B. The liquid is supplied to rotary disc 28, from which it is distributed over the internal surface of cylinder 27; it then flows over the external surface of cylindrospherical body 32, which is heated by circulating heating medium through pipes 36 and 37. The interior of the distiller is evacuated to 10-3-10-4 mm. Hg. by a multi-stage pump attached to pipe 39. The distilled vapours are condensed on cylinder 25 which is cooled by passing refrigerating medium through jacket 38. A ring 40, for maintaining distillate and distillation-residue separate, is disposed between the body 32 and the cylinder 25 at the base of the distiller B. The distillate is withdrawn, via heated pipe 41 and liquid seal 43, to receiver C1. The distillation residue collects in the interior of ring 40, and is withdrawn via cooled tube 411 and liquid seal 431 to receiver C2. The apparatus may be constructed of steel, copper or glass; the surfaces which are in contact with the hot metal being polished or chromed.