A damper is a valve or plate that stops or regulates the flow of air inside a duct, chimney, VAV box, air handle, or other air handling equipment. Its operation can be manual or automatic.
Manual dampers are turned by a handle on the outside of a duct. Automatic dampers are used to regulate airflow constantly and are operated by electric or pneumatic motors.
In a chimney flue, a damper closes off the flue to keep the weather out and warm or cool air in.This is usually done in the summer, but also sometimes in the wintet between uses. In some cases, the damper may also be partly closed to help control the rate of combustion.
Dampers are available for a wide variety of application in round ductwork, where low-leakage isolation, flow control, or a combination of the two is desired. Varying degrees of isolation can be obtained from 90 to 99,9% depending on the seal arrangement.
PED shaft seals provide a low-cost, heavy-duty design that suitable for applications up to 700oC gas temperature. Dampers are equipped with a standard outboard bearing and a frame-mounted shaft seal arrangement. This categorization allows for packing replacement without bearing removal.