Patent GB-1422949-A (GB)
Title: Process and apparatus for the production of bulked and crimped yarn
IPC: D02G1/16
Filed: 1972-10-12
Abstract: 1422949 Bulking; crimping and heating yarns JOHN HEATHCOAT & CO Ltd 16 May 1973 [17 May 1972 (2) 12 Oct 1972] 23070/72 23071/72 and 47082/72 Heading D1F In a method of continuously producing uniformly bulked and crimped yarns by use of apparatus whereby yarn is propelled e.g. into a stuffer-box (which may have a loaded end flap) or crimping tube or onto a moving restrictive surface, to form an elongated "package" or "plug" to one end of which yarn is added and to the other end of which it is removed in bulked &c state, the deviation of the position of the removal end of the "package" from a predetermined datum position is detected and a generated signal indicative of the magnitude of the deviation is used to control correctively the temperature of the yarn being fed to the apparatus whereby the bulking rate is adjusted to restore the removal end of the package to datum position. In the apparatus of Fig. 1, as the removal end of a package 12 in a stuffer tube 8 moves across a beam of light 11 emitted from a component e.g. a light bulb, 10 so a varying quantity of light impinges on a photo-electric cell 13 to generate a signal which is transmitted to electric control means 14 to effect appropriate regulation of a heating element 5 located in chamber 4 constituting heat-exchange means 3 for hot gas entering a part 2 of a nozzle assembly 1 to advance yarn 6 into the tube 8. Component 10 may emit a long narrow beam 11 which passes to component 13 by way of a set of optical fibres the light input ends of which are spaced logarithmically. The change in position of the package end may be detected by a beam of sound waves directed across the tube 8 to be received by a transducer component which transmits an electrical signal to control the operation of the heat-exchanging means. Another detector comprises electrodes disposed at opposite sides of tube 8 to form a capacitor of value which varies according to the position (or absence) of the end of the package 12 therebetween. An electro-pneumatic sensing device, Fig. 6, comprises a gas nozzle 22 the pressure within which and between a retricting orifice 25 and outlet 23 varies according to the degree of obstruction of outflow of gas by the package end and is applied to a pressure-sensitive transducer 26 which generates corrective electrical signals. In processes wherein the untreated yarn (or several such yarns) is projected, as by fluid nozzle(s) or nip rollers, onto a single moving surface e.g. a rotary drum, to form one or more side-by-side elongated packages thereon, Figs. 4 and 7 (not shown), a photo-sensitive device such as 13 may be replaced by a television camera which provides information for monitoring the behaviour of the end(s) 12, or by mechanical finger(s) actuating switching devices which control the current in electrical heat-exchange apparatus e.g. a tube surrounded by an induction coil connected to the control circuit including a high frequency generator. In other heating devices, Figs. 8, 9, 11, 12 (not shown) the yarn approaching nip rollers by which it is propelled into a stuffer-tube 8 passes around a drum or in sliding contact with a plate heated by internal or proximity electrical elements, or a portion of tube 8 is surrounded by a jacket receiving hot fluid (arranged to pass through a heat exchange apparatus) or by an induction heating coil. The apparatus of Fig. 10 comprises a drum 19 mounted at one end on a stub axle 37 and carrying several packages 12 fed simultaneously onto the surface, the other end being open to a duct 38 connected to a fan or air extractor. Light sensitive components 10 are mounted outside the drum at the removal ends of packages 12 and corresponding photosensitive components 13 are supported within the drum.