Patent GB-704460-A (GB)
Title: Improvements in or relating to a process of removing mineral oil from vegetable fibres
Inventor: OLIVER RALPH RICHARD
Filed: 1950-12-28
Abstract: Mineral oil is removed from vegetable fibres, particularly cotton, linen, hemp, jute or kapok, by soaking the fibres in an aqueous medium, removing excess aqueous medium from the fibres so that they retain approximately 45-55 per cent of the aqueous medium based on the dry weight of the fibres, subjecting the fibres to currents of air heated to approximately 120-160 DEG C until the water content of the fibres is approximately 30 per cent, and continuously withdrawing the vapours of mineral oil and water from the fibres.  After such treatment, the fibres may be further dried by air at a lower temperature.  Thus the water content of the fibres may be reduced from approximately 30 per cent to about 15 per cent by subjecting them to currents of air heated to 90-120 DEG C, and the fibres may be further dried at temperatures well below the boiling point of water. The aqueous medium used for soaking may be water or an aqueous solution of a material which, when applied to or absorbed by the fibres, makes them flame-resistant. Suitable flame-proofing materials are mixtures of borax with boric acid, ammonium phosphate, ammonium sulphate or ammonium sulphonate.  The aqueous medium may also contain a surface active agent such as an alkyl aryl sulphonate, to ensure a thorough wetting of the fibres.  In Figs. 1 and 1a, the fibrous material is fed into tank 5, containing <PICT:0704460/IV (c)/1> <PICT:0704460/IV (c)/2> the aqueous medium, preferably at 45-65 DEG C.  Rotating paddles 7 submerge the fibrous material in the aqueous medium and also propel the fibrous material through tank 5.  Rake 9 withdraws the fibrous material from tank 5 and feeds it to rollers 12 which remove the excess of aqueous medium and are so adjusted that the fibrous material discharged to conveyer 14 contains approximately 45-55 per cent aqueous medium based on the dry weight of the material.  Blower 15, picks up fibrous material on conveyer 14 and injects it, through tube 16, into the drier which is divided into three compartments by means of horizontal partitions 21 and 22.  The fibrous material passes along conveyer 25, down shoot 27, along conveyer 30, down shoot 34 and along conveyer 35, and finally leaves the drier through orifice 39. Blower 42 supplies air to the uppermost compartment via passage 41 and duct 43, a heater 40 being arranged in passage 41 so that the air enters the uppermost compartment at 120-160 DEG C.  Similarly blower 50, with the aid of heater 51 and duct 52, supplies hot air at 90-120 DEG C to the middle compartment of the drier and blower 60, with the aid of heater 61 and duct 62, supplies hot air not materially above 90 DEG C to the lowermost compartment of the drier. Blower 45 withdraws air together with oil and water vapours, from the drier via ducts 46, 47 an 49.ALSO:Mineral oil is removed from vegetable fibres, particularly cotton, linen, hemp, jute or kapok, by soaking the fibres in an aqueous medium, removing excess aqueous medium from the fibres so that they retain approximately 45-55 per cent. of the aqueous medium based on the dry weight of the fibres, subjecting the fibres to currents of air heated to approximately 120-160 DEG C. until the water content of the fibres is approximately 30 per cent., and continuously withdrawing the vapours of mineral oil and water from the fibres.  After such treatment, the fibres may be further dried by air at a lower temperature.  Thus the water content of the fibres may be reduced from approximately 30 per cent. to about 15 per cent. by subjecting them <PICT:0704460/III/1> <PICT:0704460/III/2> to current of air heated to 90-120 DEG C., and the fibres may be further dried at temperatures well below the boiling point of water.  The aqueous medium used for soaking may be water or an aqueous solution of a material which, when applied to or absorbed by the fibres, makes them flame-resistant.  Suitable flame-proofing materials are mixtures of borax with boric acid, p  ammonium phosphate, ammonium sulphate or ammonium sulphamate.  The aqueous medium may also contain a surface active agent, such as an alkyl aryl sulphonate, to ensure a thorough wetting of the fibres. In Figs. 1 and 1a the fibrous material is fed into tank 5. containing the aqueous medium, preferably at 45-65 DEG C.  Rotating paddle wheels 7 submerge the fibrous material in the aqueous medium and also propel the fibrous material through tank 5. Rake 9 withdraws the fibrous material from tank 5. and feeds it to rollers 12 which remove the excess of aqueous medium, and are so adjusted that the fibrous material discharged to conveyer 14 contains approximately 45-55 per cent. aqueous medium based on the dry weight of the material.  Blower 15, picks up fibrous material on conveyer 14 and injects it through tube 16, into the drier which is divided into three compartments by means of horizontal partitions 21 and 22.  The fibrous material passes along conveyer 25, down shoot 27, along conveyer 30, down shoot 34 and along conveyer 35, and finally leaves the drier through orifice 39. Blower 42 supplies air to the uppermost compartment via passage 41 and duct 43, a heater 40 being arranged in passage 41 so that the air enters the uppermost compartment at 120-160 DEG C.  Similarly blower 50, with the aid of heater 51 and duct 52, supplies hot air at 90-120 DEG C. to the middle compartment of the drier and blower 60 with the aid of heater 61 and duct 62, supplies hot air not materially above 90 DEG C. to the lowermost compartment of the drier. Blower 45 withdraws air, together with oil and water vapours, from the drier via ducts 46, 47 and 49.