| 摘要 |
<p>A pressure relief panel assembly (20) for rupture discs, explosion vents and the like has a plurality of frangible panel portions (140, 44, 50) which burst at different pressures to present a pressure relieving aperture having a cross-sectional area which varies in accordance with the number of panel portions (40, 44, 50) which have ruptured. In one embodiment of the invention, the assembly comprises two frangible panels (26, 30) positioned in face-to-face relationship in covering disposition to a vent opening, and the innermost panel has an orifice which functions as a pressure relieving aperture once the outermost panel ruptures; subsequently, further build up of pressure causes the innermost panel to burst and present a pressure relieving aperture larger than the orifice so that the structure to be protected is fully vented. In certain forms of the invention, a discontinuous pattern of perforated lines of weakness in the innermost panel serve as pressure relieving apertures once the outermost panel ruptures. In another embodiment, the assembly comprises a single panel (125) having one set of weakness lines (142) defining a first frangible panel portion (140) and a second set of weakness lines (142) surrounding the first set and defining a second frangible panel portion (144).</p> |
