GB553765A - Improvements in or relating to the production of textile fibres - Google Patents

Abstract

553,765. Treating flax straw. FRAZER & HAUGHTON, Ltd., and BUTTERWORTH, E. Aug. 29, 1941, Nos. 11073/41 and 2794/42. [Classes 120 (i) and 120 (iii)] [Also in Group IV] Flax straw, especially unretted flax straw, from which line fibre is to be extracted by mechanical means, is pretreated by subjecting it for a relatively short time to the joint effect of heat and aqueous moisture, e.g. by steaming, so as to cause condensations or deposit of moisture on the fibre layers limited to a degree such that the fibre layers are moistened and softened while the woody core remains comparatively unaffected; the differential moistening effect thus obtained reduces or obviates brittleness and cutting of the fibre during the mechanical treatment and avoids undue wetness or softening of the woody core which would give difficulty in separating it from the fibres. Straw having a moisture content of the order of 11 to 14 per cent by weight of the straw is subjected to steaming for about half a minute to about five minutes and the treatment may increase only or mainly the moisture content of the fibe layers so that the total moisture content is about 13 per cent to 15 per cent. The straw may be heated and then subjected to moistening in a saturated or nearly saturated atmosphere or to moistening by a spray of water or a steam jet. The straw may be conveyed through a steaming chamber 3, Figs. 1 and 3, by a conveyer 1 driven at a controlled speed by rollers 2; the chamber has a side slot 5 and end slots 4 and a controlled supply of steam is released in the chamber, below the top flight of the conveyer, from a pipe 6. The width of the chamber is such that the top or seed ends of the stalks do not pass through it or the slotted side wall may be inclined so that the top ends are given a progressive steaming treatment or it may be stepped so that the top ends receive a shorter steaming treatment or the part of the slot in the chamber receiving the top ends may be wider than the part receiving the remainder of the stalks. The steaming apparatus may be combined with a breaking and/or scutching machine.