Butterfly damper

Function

Butterfly damper, which is also known as wafer damper, is used for regulation or on/off application in flue & air duct. For butterfly damper with small diameter, it could play both functions. For the one with big diameter, regulation is not so precise, on/off is the main purpose.

Types

• By operation: manual, electric, pneumatic.
• By fabrication process: casting, welding
• By material: cast iron, carbon steel, stainless steel, rare earth treated steel
• By number of shaft & disc: single, multiple

Features

Typical butterfly damper is single shaft & disc structure. For small units, bearing journal adopts inner support and outer gland seal. Sliding bearing sleeve is used for support.

To meet with high requirement for large units like 600MW, 900MW, 1000MW, we expand model specifications and optimize structure of butterfly damper. The maximum diameter is up to DN8000 now. New design adopts inner seal and outer support for bearing journal. Packing material is featured with good sealing, no leakage, heat resistant. Self-lubricating, self-aligning bearing could compensate concentricity deviation of shaft supports to ensure small resistance, no jamming, smooth on & off operation.

Double eccentric heat resistant butterfly damper uses metallic seal to improve its shutoff performance in hot environment. Hard seal by alloy overlaying goes through finish machining to ensure flatness of sealing surface. It is used in following occasions:

• Ash content in fluid is high, and air tightness is critical
• Guillotine damper can’t be used due to limited space

For example, flue gas recirculation pipeline, pulverized coal purging pipeline, etc.

Wearing resistant butterfly damper is fabricated with raw earth treated steel or lined with ceramics. It has not only good resistance to wearing, but also high temperature. Its service life is 3-5 times of common product.