| 摘要 |
<p>A duct insulation board grooving apparatus (20) cuts a plurality of parallel grooves (66) into duct boards (46) with a plurality of rotary saw blades (50) which are spaced on 1.57 inch or 3.14 inch centers. The saw blade (50) have peripheral teeth (62) which project outwardly on both sides (64) of the saw blades to form grooves (66) in a first major surface of a duct board (46) which are wider than the saw blades. The grooves (66) have sidewalls which extend perpendicular to the first major surfaces of the duct board and have a depth from 70 to 90 of the thickness of the duct board. The first major surface is typically coated and a second surface of the duct board normally has a facing adhered thereto. After the duct board (46) is grooved, the duct board can be curved to conform to the curvature of a tubular metal shell (80), with the parallel grooves (66) of the duct board (46) extending parallel to the axis of curvature, and placed in the tubular metal shell (80) as a liner to form an insulated air duct.</p> |
