| 摘要 |
<p>A vacuum relief and access door assembly, for use on a duct downstream of a fire or control dampers, comprises a frame including a duct facing surface with a seal member thereon, a closure member having side edges in sealing engagement with the seal member, and cooperative retaining members mounted on the frame and closure member and resiliently urging the closure member into sealing engagement with the seal member, yielding to allow the closure member to displace toward the duct to allow air flow thereby for vacuum relief and returning into sealing engagement with the seal member said retaining members being releasable for removal of said closure member.</p> |
