CIRCULAR ISOLATION DAMPERS
This type of unit consists of a short section of duct with flange type connections at each end. The blade rotates on stainless steel stub shafts which are welded to the blade on assembly:. It is impossible for the blade to become detached and lost down the duct. Units designed for isolation duty normally have a full metallic ledge type airstop, although alternatives such as soft or spring types are available. Balancing dampers are usually fitted with a simple stop.
The shafts are normally supported in Oilite type sintered phosphor bronze bushes which can be regarded zero maintenance. In the extremely unlikely event that they become worn or are damaged, they can be replaced with the damper in place.
The unit illustrated has a lever and quadrant type manual operator. However, any type of actuator can be supplied, including pneumatic, electric and hydraulic.