1. Main Duct Layout Guidelines
(1) Path Planning: The main duct should follow the shortest path principle, with straight sections accounting for no less than 70%. When a turn is necessary, a large radius of curvature (R≥3D, where D is the pipe diameter) should be used to reduce local resistance loss.
(2) Slope Design: Horizontal main ducts should maintain a slope of 0.5%-1%, sloping towards the dust collector to facilitate natural dust sliding. A dust removal port should be installed at the bottom of vertical ducts.
(3) Pipe Diameter Calculation: The pipe diameter is determined based on the total system air volume (Q) and recommended air velocity (v=18-22m/s). The calculation formula is: D=√(4Q/πv), with units converted to international standard units.
2. Branch Pipe System Configuration
(1) Material Selection: PVC or PP materials are recommended for branch pipes, as their friction resistance coefficient (λ=0.015-0.025) is significantly lower than that of metal pipes. For high-temperature conditions (>80℃), galvanized steel or stainless steel should be used instead.
(2) Connection method: The connection between the branch pipe and the main duct should use a 45° oblique joint or a baffle design to avoid vortices caused by right-angle connections. Flexible joints should be installed at the connection points to eliminate vibration transmission.
(3) Airflow balance: The airflow velocity in the branch pipe should be controlled at 70%-80% of that in the main duct. Airflow balance in each branch should be achieved through regulating valves, and the total system resistance deviation should be ≤15%.