Stack Damper

All of the furnaces used in process operations are equipped with fairly tall stacks (chimneys). The purpose of these stacks is to release flue gas at a high altitude to allow adequate dispersion.

The stacks are also used to create draft. The term "draft" refers to the static pressure inside the furnace. Due to the chimney effect created by the stack a slight vacuum is created at the bottom of the stack. This vacuum creates a suction effect, and draws flue gases through the furnace into the stack.

To control the flow of flue gas, stacks are provided with a stack damper. Usually a stack damper has a large butterfly-valve type construction. To control the flue gas flow through the stack, the position of the stack damper is varied. It is very important for the operators to keep an eye on the stack damper. The position of the stack damper also controls the draft in the furnace.