A method of making a duct member

摘要

A method of making a duct member comprises feeding sheet metal continuously from a roll, progressively folding the opposite edges of the sheet as it advances to form a respective folded metal catch (14', 16') along each edge. Each catch includes an upstanding wall (102, 104) defining with the main body (106) of the sheet a shallow tray across the width of the sheet. A thermal insulator is dispensed in flowable form into the shallow tray as the sheet advances so that the thermal insulator spreads out to fill substantially the full width of the tray between the upstanding walls. The liquid thereafter solidifies to form a solid thermally insulating layer (110). The sheet is cut transversely into individual panels (100) having a respective catch along each edge for in-use push fit connection to a cooperating catch along the edge of an adjacent panel.