Patent GB-620440-A (GB)
Title: Improvements in or relating to continuous processes for the production and treatmentof artificial threads and apparatus therefor
IPC: D01F2/06
Filed: 1947-01-17
Abstract: <PICT:0620440/IV (a)/1> <PICT:0620440/IV (a)/2> <PICT:0620440/IV (a)/3> <PICT:0620440/IV (a)/4> Means are provided for facilitating starting-up at the beginning of an operation or after a break in the continuous production and collection of artificial threads by a method involving treatment of the newly-spun thread with hot water or hot dilute acid and at the same time stretching the thread to 110-180 per cent of its length by interposing a godet between the spinning bath and the hot treatment bath and passing the thread from this bath to a pair of mutually inclined rollers revolving at a greater peripheral speed than that of the godet, traversing the thread round the rollers in a succession of helical loops whilst it is being washed and dried, and then collecting the thread.  For facilitating starting - up, the diameter and surface of the godet are made such as to allow slippage of the thread at contact angles of less than 180 degrees whilst ensuring a grip on the thread at greater contact angles, e.g. between 300 and 360 degrees, and means are provided for diverting the thread from the direct path between the spinneret and the rollers to a path which includes the godet and the hot treatment bath, and for diverting the path of the thread near to and on one side or on both sides of the godet so as to vary the contact angle. A godet of about 6 1/4 inches diameter and having a surface of smooth ebonite without serrations may be used.  Provided the surface of the godet is thoroughly wet with the coagulating liquor the surface of the godet may be of glazed, fine mat or mat porcelain.  The presence of a wetting agent in the coagulating liquor ensures easy wetting of the godet. If the thread is to be stretched by a small extent only, e.g. 10-25 per cent, the tension on the thread is low and a godet of smaller diameter, e.g. 4-5 inches may be used.  As shown in Fig. 1, artificial thread issues from spinneret 1 and passes from coagulating bath 2 to a pair of inclined rollers 3, 4, round which it passes in helical loops.  A freely rotating runner 6 is caused to engage the thread and draw it over godet 5 and down into the hot bath 7.  The runner 6 then takes up a permanent position 8 as shown in Fig. 2. The contact angle of the thread as it passes over the godet 5 is at this stage below 180 degrees so that slippage occurs.  Freely rotating runners 9, 10 are then applied to the thread below the godet so as to increase the contact angle to 330-360 degrees.  The thread then follows the path shown in Fig. 3, and stretching between the godet and the pair of rollers 3, 4 takes place.  If desired, the runners 9, 10 may be taken to positions such as those shown in Fig. 5.  Movable low-friction guides may be used in place of the freely rotating runners 6, 9, 10.  The godet 5 may supply one or more pairs of skew rollers, each pair having separate spinneret, runners and guides.  If desired, the godet may be placed between the two baths at the same level or below them.