Duct Flange

A duct flange is a standardized mechanical interface used to connect ductwork sections in industrial ventilation and fume extraction systems. It consists of a flat, ring-shaped plate with evenly spaced bolt holes that align with corresponding flanges on adjacent duct sections. When bolted together with gaskets, it creates a secure, airtight connection that prevents leakage of contaminated air, maintains system pressure, and allows for modular assembly and disassembly for maintenance. In fume extraction hood applications, flanges are critical for maintaining negative pressure and ensuring efficient capture of hazardous fumes, vapors, and particulates at their source.

The duct flange operates on the principle of mechanical compression sealing. When two flanged duct ends are aligned and bolted together with an intermediate gasket, the applied torque creates uniform pressure across the gasket surface. This compression deforms the gasket material to fill microscopic imperfections in the flange faces, creating an airtight barrier. The flange's structural rigidity distributes mechanical loads from duct weight, thermal expansion, and system pressure evenly across the connection, preventing distortion and maintaining alignment. In fume extraction systems, this sealed connection maintains the designed airflow velocity and negative pressure necessary for effective contaminant capture.