GB811128A - Improvements relating to the production of artificial filaments - Google Patents

Abstract

<PICT:0811128/IV (a)/1> <PICT:0811128/IV (a)/2> <PICT:0811128/IV (a)/3> Apparatus for supplying a spinning solution to a jet to form slub yarns comprises a metering pump provided with an intermittently opened by-pass valve, which permits the intermittent connection of the output side of the pump with the input side, and a throttle valve, in series with the by-pass valve, to enable the differences in cross-sectional area of the yarn to be varied. As shown in Figs. 1 and 2, the pump body consists of end plates 1, 2, a shell 3 and a coverplate 4. The pump members are two meshing gear-wheels 5, 6, wheel 5 being freely rotatable in the shell 3 and wheel 6 being secured by a pin 8 to a driving shaft 7 journalled in the plates 1, 2. An inlet passage 9 is formed in the plate 1 and an outlet passage 10 in the plate 2, these passages opering on opposite sides of the nip of the gear-wheels 5, 6, as shown in Fig. 1. The shaft 7 also carries a rotary valve member 11 housed in a cavity 14 of the cover-plate 4 and secured to the shaft by a pin 12. As shown in Fig. 2, this valve member is a disc having four notches 13 formed in its periphery. These notches may be equally or unequally spaced, and may be of equal or differing circumferential extent. The outlet passage 10 in the plate 2 opens into the cavity 14 at 15. A by-pass passage is formed by a port 16 in the left-hand side of the plate 2, as shown in Fig. 2, leading to a transverse bore 18 in the plate 2 which leads to a bore 19 opening into the cavity 14 in the cover-plate 4 in such a position that it is alternately uncovered and covered by the notches and lands of the valve member 11. The port 16 is on the inlet side of the gears 5, 6. The bore 18 is formed with a valve seat 20 and houses a needle valve 21 on a screw-threaded spindle 22, so that the valve can be adjusted in relation to the seat 20 to regulate the rate of flow of spinning solution through the by-pass passage. As the gear-wheels 5, 6, shaft 7 and valve member 11 rotate, the valve member 11 alternately covers and uncovers the port 19, causing intermittent escape of spinning solution from the delivery passage 10 to the inlet passage 9. In an alternative construction (Fig. 3), a conventional metering pump 28, which may be of the geared type, delivering spinning solution to a jet 27, is by-passed by a pipe 29 which includes a throttling needle valve 23 and a rotary valve 24 having a number of ports 25. The valve 24 may be driven by the same source of power as the pump 28, or independently, and the valve 23 may be adjusted continuously and automatically, for example by a cam 26 driven by the pump or valve motor, or independently. Specification 589,038 and U.S.A. Specification 2,391,973 are referred to.