to the interconnected points application_number US 1277179 A description as shown in fig1 the system will be described commencing with the yarn strands being withdrawn from sliver containers 10 and 11 the yarn strands 12 and 13 being subjected to a drafting or drawing process by pulling the yarns between drafting rolls yarn 12 being drawn by drafting rolls 14 and 15 and yarn 13 being drawn by rolls 16 and 17 roll 15 typically is driven at a surface velocity greater than that of roll 14 and roll 17 is driven at a surface velocity greater than roll 16 the yarns can then be passed through primary twist jets yarn 12 being passed through primary twist jet 18 and yarn 13 being drawn through primary twist jet 19 the primary twist jets operate to impart and maintain twist at the critical point where the otherwise flat sliver ribbon leaves the draft delivery rolls yarn strand 12 is passed through a singles twist jet 20 and yarn 19 is passed through a singles twist jet 21 wherein the twist is inserted in the yarn strands air pressure under the control of apparatus not shown is supplied to jets 20 and 21 through conduits 22 and 23 respectively such control apparatus may be fluidic valves electrical valves or mechanically operated valves such apparatus being conventionally available an example thereof is to be found.