Filaments Velocity in a Slit-Type Interlacer: Role of Supplied Air Pressure

For the purpose of making clear the mechanism of interlacing process in a slit-type interlacer, an effect of supplied air pressure on both filaments velocity and its characteristics was studied using a high-speed video camera and particle image velocimetry. Results obtained are as follows: (1) Filaments must produce an opening state of twin spirals to generate tangling parts. It was confirmed that the tangling parts were generated at smaller amount of filaments movement at high supplied air pressure and the opening state became longer time at low supplied air pressure. In addition, filaments in an opening state in left and right regions of the yarn passage need to change their relative positions by crossing the symmetric plane of yarn passage to different region above 300 to 400 filaments. This series of processes produces an interlaced yarn owing to twists accumulated at both ends of opening part. (2) Either fast filament motion or long opening state time can generate tangling parts even when the twin spiral motion of filaments was asymmetric. (3) As the supplied air pressure increased, the position-time-mean angular velocity became large, thus an increment of supplied air pressure was effective to generate tangling parts. (4) In the tangling state, the time-position-mean of magnitude of velocity increased with increasing supplied air pressure, but the time-position-mean of magnitude of its deviation was almost constant, because filaments formed one bundle. On the other hand, in the opening state, the time-position-mean of magnitude of velocity increased with increasing supplied air pressure from 0.1 MPa to 0.3 MPa, but indicated almost the same value in the supplied air pressures between 0.3 MPa and 0.5 MPa. However, the time-position-mean of deviation of magnitude of velocity was independent of the supplied air pressure. (5) This and our previous studies are available for design guideline of an optimum interlacer.