Cotton Polyester Blend Separation Mechanics during Mechanical Opening
Mechanical opening separates cotton and polyester blends when differences in fiber density, crimp, and friction cause differential transport and waste drop.
Pneumatic Conveying Velocity
Airflow Velocity
Aerodynamic velocity parameters in transport pipelines govern the movement of loose textile fibers from the opening room to the carding line. Maintaining the correct pneumatic conveying velocity is critical to prevent the fibers from settling inside the ductwork. If the velocity falls below the saltation limit, fibers accumulate and block the pipes.
Transport Boundary
High air velocities keep the fibers suspended in the center of the air stream, reducing contact with the pipe walls. However, an excessively high pneumatic conveying velocity causes the fiber tufts to roll and rub against the ducting. This friction generates rolled fiber defects known as neps, which degrade the final yarn quality.
Frictional Drag
Duct geometry and the number of elbows in the line influence the pressure drop and require adjustments to the fan speed. To balance these factors, the system must operate within a narrow range of twelve to eighteen meters per second. At this speed, the aerodynamic drag overcomes the gravitational settling force without causing fiber damage.
It also ensures that the fibers are delivered to the carding chutes in an opened, lofty state rather than compressed clumps.
Power Efficiency
Optimizing the airflow reduces the energy consumed by the high-pressure transport fans. Lowering the velocity to the minimum safe threshold saves electricity while maintaining consistent line productivity.