Abstract: In general, a sealing apparatus for substantially preventing the flow of air through a damper assembly having a plurality of movable vanes includes a first, rigid sealing member having a generally circular cross-section and adapted to be attached to a first edge of a first movable vane. The first edge is movable through a first arc between a damper-open position and a damper-closed position. A second resilient sealing member has a generally rectangular cross-section and is adapted to be attached to a second edge of a second movable vane. The second edge is movable through a second arc between the damper-open and damper-closed positions. The sealing members make substantially line contact one with the other as the edges are moved toward the damper-closed position and are in substantially gas flow-preventing area contact one with the other when the vanes are in the damper-closed position.

Abstract: A multiple bladed air damper unit for heating, ventilating and air conditioning systems includes separate and individual end edge seal elements sealing off the end edges to the frame in the closed position. The seal elements are mounted in end-to-end relation and define an essential continuous flat sealing surface in opposed, abutting alignment with the individual flat planar end edges of the blades. Each seal element is a thin, spring-like resilient metal plate of a length essentially identical to that of the end edge of the blades. The metal seal element has a crowned cross-section defining a central, generally flat seal portion integrally interconnected by inclined walls to mounting edges. A central opening is provided for the blade pivot shaft. The element is compressed between the end of an aligned blade and the damper frame to establish a resilient, sliding engagement between the blade and flat seal portion.

Abstract: A pneumatic actuator includes a cup-shape cylinder body housing a piston and having a generally flat base with a mounting hub projecting outwardly. A piston rod is slidably mounted in the hub and connects to a load such as a damper in an air mixing box. The base is formed with a bearing recess or depression means encircling the hub. The recess defines a spherical sector offset from the center of a complete sphere of the same radius. An annular swivel ring includes an inner diameter adapted to loosely fit over the hub and includes an outer periphery which is generally spherically shaped and defines a central spherical sector having a maximum planar diameter slightly larger than that of the sector defined by recess. The swivel ring is a two-part member having interconnecting slot and projection elements providing a snap joint connection, with the mounting plate firmly clamped therebetween. The swivel ring with the attachment plate fits over the mounting hub.