GB605302A - Method and apparatus for expressing oil - Google Patents

Abstract

<PICT:0605302/III/1> <PICT:0605302/III/2> Oil is obtained from oil-bearing nuts, seeds, &c. by heating (cooking) them for a relatively extended period, e.g. 30 to 90 minutes at a temperature appreciably, e.g. at least 10 DEG F. lower than the predetermined optimum oil-expressing temperature for the particular material, thereafter, and without substantial intervening loss of time or temperature, subjecting said material to a conditioning treatment to reduce and stabilize the moisture content, during a period of shorter duration, e.g. 7 to 15 minutes, than that of said heating treatment, but at a temperature higher than the first heating temperature, but not higher than said optimum oil-expressing temperature, and at the conclusion of said conditioning treatment, without substantial loss of time or temperature, subjecting said material at said optimum temperature to continuous expressing action for removing oil. The quantity of material at any time in the cooker may be over 25 times, e.g. 40 times the quantity then undergoing expression and may be continuously fed to the cooker, undergoing a gradual rise in temperature during its passage through this vessel to a value below the optimum oil-expressing temperature. In the illustrated embodiment of the invention the material supplied from the hopper 7 is continuously fed by means of the variable screw-type feeder 8 through a conduit 11 into the steam-jacketted horizontal elongated cooking vessel 6 of relatively large diameter, 6 is provided with vents 21 fitted with adjustable doors or dampers to control the rate of escape of any water vapour given off and with an automatic thermo-regulator 55, 57 and temperature recorder 58. The material is thoroughly agitated and made to advance slowly through the cooker to the discharge end by means of a combined agitator and conveyer consisting of two series of oppositely inclined spiral vanes 18 and 19 mounted upon the shaft 17. It is discharged through the conduit 24, short variable feeder (screw type) 25 and conduit 26 into the steam jacketted cylindrical conditioning vessel 5 which is of the same general construction as the cooker, but of smaller diameter. It has similar fittings, including a combined agitator and conveyer rotating at a higher speed than that in the cooker, and the material dehydrated to the required degree is continuously discharged from the conditioner through the feed chute 4 into the vertical feed press 3 from which it passes to the horizontal main press 2. The cooker and conditioner have capacities which respectively are, at least twenty-five to forty, and five times the capacity of the press. The process is said to increase the yield and quality of the oil and to conserve heat. Flaxseed and linseed yield cakes of improved quality and in the extraction of tung oil the desirable condition of reducing access of air to the material to a minimum may be achieved.