Apparatus for the production of fixed point multifilament yarns

Apparatus for the interlacing of multifilament yarns to produce fixed point multifilament yarns, the apparatus comprising

• an interlacing unit having a bore, a rotatable body arranged in said bore, a longitudinal passage for accommodating multifilament yarns during treatment therein, said passage having a longitudinal direction with a first portion formed in said rotatable body and a second position formed by a wall portion of said bore, an elongate lateral slot intersecting said bore;
• means for moving the multifilament yarns through said passage under tension at speeds in excess of 1000 meters per minute;
• a pneumatic positioning motor for rotating said rotatable body to position said first portion of said passage in a threading position in alignment with said slot, whereby multifilament yarns can be inserted through said slot into said first portion of said passage and whereby said lateral slot is closed by said rotatable body on rotation of said rotatable body to an operating position in which said first portion of said passage is aligned with said second portion of said passage;
• a blasting nozzle in the form of De Laval nozzle having a convergent section leading to a throat and a divergent section extending through said interlacing unit to open into said passage transversely to said longitudinal direction at an angle in the range of from 60.degree. to 90.degree. to said longitudinal direction, said divergent section having an opening at a junction with said passage extending peripherally of said passage in the range from 0.2 to 0.5 times the peripheral length of said passage;
• gas source means for blowing gas under pressure into said De Laval nozzle to cause the gas to emerge in a stream through said opening into said passage at a desired speed to effect interlacing;
• means for varying said gas pressure to select said desired speed;
• a gas supply line extending from said means for varying said gas pressure to select said desired speed to said De Laval nozzle;
• and
• means for connecting said pneumatic positioning motor to said gas supply line whereby on supply of gas to said De Laval nozzle, said positioning motor is actuated to move said rotatable body from said threading position to said operating position.