GB1054774A - - Google Patents

Abstract

1,054,774. Liquid diffusion apparatus. G. G. HAVENS. July 2, 1966 [July 10, l962], No. 26132/63. Headings B1X and B2K. A solvent separation apparatus includes a plurality of elongate rigid porous tubes having a semipermeable membrane on either the inner or outer surface thereof, the tubes being operative to pass water at a higher rate than dissolved salts and means for circulating a solution at a pressure exceeding the osmotic pressure difference across the membrane. Saline water is maintained at 1000 to 1500 p.s.i. by pump 12, the water being circulated by way of tubes 14, tank 18 and pump 20. A salinity monitor automatically bleeds off brine at valve 22 when the salt concentration is high. Tierods 44 through end supports 36 hold the porous tubes against gasket 40 in the pressure vessel 24. The tubes are made from a glass fibre screen, mesh or fabric impregnated with a phenolic resin thereby giving a porous tube upon curing. The tubes are manufactured by winding with a bias ribbons of resin impregnated fabric on a mandrel coated with a parting agent. The wound mandrel is wrapped in cellulose acetate, cured at 180‹C for 2 hrs. and the cellulose acetate removed. A solution of cellulose acetate, acetone and aqueous magnesium perchlorate is used to coat the porous tubes which is subsequently treated at room temperature, 0‹, 30 to 50‹ and finally 80‹C. The porous tubes may be modified by interposing a layer of unimpregnated fibre e.g. a spiral wrapping of glass fibre roving, between the impregnated tube and the semi-permeable membrane. A further modification is the use of a pattern of grooves to promote the formation of conical pores or gaseous inclusions which aid diffusion speeds. An alternative embodiment (Fig. 5, not shown) incorporates a series of cylindrical tubes closed at one end within a pressure vessel, the vessel containing saline water while the membrane is on the outside of the tubes.