A damper for a vent system of a safety cabinet, the damper comprising:
- a body, the body extending along a longitudinal axis and having a first end and a second end, the ends disposed in spaced relationship to each other along the longitudinal axis, the body defining a passage with a first opening disposed at the first end and a second opening disposed at the second end;
- a valve plate, the valve plate disposed within the passage of the body such that the valve plate is intermediately disposed along the longitudinal axis between the first end and the second end of the body, the valve plate being movable between an open position and a closed position, the valve plate permitting air flow between the openings of the passage of the body when the valve plate is in the open position, and the valve plate substantially occluding the passage of the body when the valve plate is in the closed position;
- a pivot assembly, the pivot assembly including a valve support assembly, a biasing system, and a fusible link, the valve support assembly mounted to the body and the valve plate, the valve support assembly adapted to support the valve plate such that the valve plate is movable between the open position and the closed position, the biasing system mounted to the body and at least one of the valve plate and the valve support assembly, the biasing system adapted to bias the valve plate to the closed position, and the fusible link interconnected between the body and the biasing system to form an interconnection therebetween such that the valve plate is disposed in the open position, the fusible link constraining the valve plate from moving from the open position to the closed position via the interconnection of the fusible link between the body and the biasing system, and the fusible link being configured to melt at a predetermined temperature to thereby disengage the interconnection of the fusible link between the biasing system and the body and to thereby allow the biasing system to move the valve plate to the closed position;
- wherein the body includes an exterior surface and an interior surface, the interior surface being generally cylindrical and defining the passage thereof, the exterior surface being in outer radial circumscribing relationship to the interior surface, the body defining a pair of cross bores, the cross bores being in opposing relationship to each other and each extending radially from the exterior surface to the interior surface, and wherein the valve support assembly includes a pair of trunnion members, the trunnion members being connected to the valve plate such that the trunnion members extend, respectively, from the valve plate into the cross bores, the trunnion members and the valve plate being pivotable about a pivot axis with respect to the body;
- wherein the biasing system includes a drive sleeve, a pivot arm, and a spring, the drive sleeve extending along the pivot axis through one of the cross bores of the body, the drive sleeve including an inner end and an outer end, the inner end of the drive sleeve coupled to the valve plate such that rotational movement of the drive sleeve about the pivot axis correspondingly rotates the valve plate, the outer end of the drive sleeve being disposed in outer relationship to the exterior surface of the body, the pivot arm being mounted to the drive sleeve adjacent the outer end thereof such that a distal end of the pivot arm projects from the drive sleeve, the spring being mounted to the body and to the pivot arm such that the spring exerts a spring force against the drive sleeve configured to rotate the drive sleeve about the pivot axis in a closing direction to move the valve plate from the open position to the closed position, the fusible link retentively connected to the body and to the pivot arm to constrain the rotational movement of the drive sleeve about the pivot axis such that the valve plate is disposed in the open position;
- wherein the interior surface of the body includes a first projection and a second projection, the first and second projections extending radially inwardly toward each other, and the valve plate being in contacting engagement with the first projection and the second projection when the valve plate is in the closed position, the valve support assembly being adapted to support the valve plate such that the valve plate is rotatably movable about the pivot axis between the open position and the closed position, the valve plate rotating about the pivot axis in a closing direction when moving from the open position to the closed position, the first projection includes a first valve seat surface extending radially inwardly and facing the second end of the body, and the second projection includes a second valve seat surface extending radially inwardly and facing the first end of the body, wherein the valve plate includes a first face and a second face in opposing relationship to the first face, the first and second valve seat surfaces being configured to interferingly engage the first and second faces of the valve plate, respectively, when the valve plate is in the closed position to prevent the valve plate from rotating from the open position further about the pivot axis in the closing direction.