GB821179A - A method and a device for crimping thermoplastic threads in a stuffer box - Google Patents

Abstract

821,179. Crimping yarn. ONDERZOEKINGSINSTITUUT RESEARCH N.V. April 2, 1957 [May 24, 1956], No. 10791/57. Class 120(3) In a method of crimping thermoplastic threads in which the threads are fed by clamping rollers into a heated portion of a stuffer box against the action of a mechanicalpressure, cooled in another portion of the box and finally released therefrom, a thread is led upwardly into a box containing balls the diameter of which are such that, above the nip of the rollers, two or more balls may simultaneously find a berth on both rollers and the number of balls is such that they fill the box to above the rollers when piled thereon and entirely cover the compressed thread during the crimping operation. At the commencement of crimping, the halls prevent the thread from fouling the junction between the ends of the rollers and the box; as crimping proceeds; the balls are propelled upwardly and form, on top of the compressed thread, one or more layers which promote uniform release of the thread and provide or contribute (together with a conventional piston) to the mechanical pressure. In the apparatus shown in Figs. 2 and 3, representing the static and crimping conditions, a tubular stuffer box 3 having a polytetrafluorethene lining 13 cooling ribs 4 and an apertured closure lid 14 carries a chamber 10, connected to a discharge (or delivery) pipe 11 and communicating with the box interior by radial channels 12, and is formed to accommodate and is urged by a spring 8 to engage spring-loaded driven clamping rollers 1, and contains balls 16. The thread may be preheated by passage through a capillary tube 18 of a tube system 17 which receives air from a pipe 21 heats it e.g. to 160‹C, by means of an electric element 22 and ejects it in the nip of the rollers 1 through the apertures formed at each side of the flattened end of a tube 19; this hot air and also the downwardly moving cool air passing through the compressed thread in the lower and upper part of the box are withdrawn through channels 12 and chamber 10. The lower end of the box 3 may be surrounded by a supplementary heating device and preheated air supplied to the box, above the rollers, e.g. from the chamber 10, may be further heated thereby e.g. to 190‹C. In the latter case, all hot air and the countercurrent of cooling air entering through the aperture 15 are withdrawn from the box at a point intermediate the supplementary heating device and the top of the compressed thread; the tube system 17 may be omitted.