Patent GB-812022-A (GB)
Title: Improvements in and relating to the production of yarn of irregular denier
Inventor: KENNEDY WILLIAM
IPC: D01D5/20
Filed: 1956-06-27
Abstract: Apparatus for producing a slub yarn by superimposing pulses of fibre-forming liquid upon a constant supply of fibre-forming liquid to a spinning jet comprises a metering pump for maintaining a constant supply of a fibre-forming liquid through a supply pipe to the jet, and a plunger pump for injecting sharply defined pulses of fibre-forming liquid into the supply pipe.  The quantity of liquid delivered by each stroke of the plunger pump may be varied and also the number of strokes per minute.  As shown in Fig. 1, viscose is pumped at a constant rate by a standard gear pump 1 from a main 2 through a pipe 3 and a feed pipe 4 to a spinning jet 5 immersed in a spin bath (not shown) so that an artificial yarn 6 is produced. Pulses of viscose are also pumped into the feed pipe 4 from the main 2 through pipes 7, 8 by means of a standard fuel injection pump 9 (of the type used in Diesel engines) mounted on a bracket 34 and operated pneumatically by compressed air from a supply pipe 10 through a solenoid-operated valve 11 and pipe 12.  The solenoid 13 of <PICT:0812022/IV (a)/1> <PICT:0812022/IV (a)/2> the valve 11 is excited by electric pulses derived from any convenient source, for example by switching an electric circuit with a toothed cam or by an electronic unit switched by cosmic radiation, as described in Specification 703,697.  The pump 9, as shown in Fig. 2, has fitted on the operating end a cylinder 14 housing a free piston 15.  Compressed air from pipe 12 enters the cylinder 14 through a port 16 and drives the piston 15 against a sleeve guide 17 which in turn drives an injection plunger 18 to the left in the cylinder 19, masking inlet ports 28A, 28B. Viscose that has been previously drawn through these ports into a space 20 in the cylinder 19 in front of the head of the plunger 18 is forced through a channel 21 past a spring-loaded non-return valve 22 so that a pulse of viscose passes out through a port 23 into the pipe 8.  On the release of compressed air from the cylinder 14, the plunger 18, the guide 17 and the piston 15 return to the right under the influence of a return spring 24, and viscose is drawn into the space 20 through the ports 28A, 28B from the pipe 7 by way of a passage 25.  The volume of viscose passing through the port 23 per pump stroke may be predetermined by a known method of metering in the pump 9.  The head of the plunger 18 has a longitudinal groove 26 which communicates with a helical groove 27.  When the plunger 18 moves to the left viscose is forced into both grooves 26, 27.  At some point in the travel of the plunger 18, the helical groove 27 comes into register with the port 28B, through which the resistance to flow is less than through the channel 21 and valve 22, so that viscose remaining in the space 20 is forced back into the passage 25. The point at which the groove 27 and the port 28B register may be varied by rotating the plunger 18 by means of a rack 29 meshing with a pinion 30 on a sleeve 31 which is connected to the plunger 18 by a lug 32.  With this apparatus yarn 6 (Fig. 1) having short slubs 33 with sharply defined leading and trailing ends and with varying denier and length may be produced at a rate of up to 200 or more slubs per minute.