Purification Mechanism
A sequential mechanical separation process extracts microscopic contaminants and undissolved gels from a viscous polymer melt before extrusion. This method of double pass filtration routes the fluid through two distinct, consecutive barrier stages of increasing fineness. Fine spinnerets used in synthetic yarn production require this treatment to prevent capillary blockages and filament breakages.
The purification mechanism of double pass filtration maintains the structural integrity of the extruded fibre.
Operational Sequence
The fluid first enters a primary screen that captures large agglomerates and foreign particulate matter. After this initial screening, the partially clarified polymer passes through a second, denser metal-powder or sintered-metal media. This secondary stage of double pass filtration removes the microscopic gels that escaped the initial pass.
Splitting the pressure drop across two stages reduces the risk of polymer degradation.
Performance Limit
High-viscosity polymers containing recycled content represent the limit where this system becomes economically challenging. While double pass filtration cleans recycled polyester melt effectively, heavily contaminated inputs cause rapid pressure spikes and frequent filter changes. Operators must balance the increased purity against the higher energy demands and downtime associated with servicing the dual housings.
Process Value
Implementing this two-stage method minimizes yarn defects like slubs and weak spots in polyester filament. Using double pass filtration ensures uniform dye uptake by removing gel particles that cause uneven dye absorption. Manufacturers achieve higher yield and fewer rejects during the high-speed texturizing process.
