A flanged butterfly valve is a type of butterfly valve installed in pipeline systems via flanged connections. Its core function is to control medium flow or achieve shut-off by rotating the disc (0°–90°). It is widely used in water supply/drainage and gas pipelines for industries such as water treatment plants, power plants, chemicals, food, and pharmaceuticals.
Structural Features
Connection Method
The valve body comes with flanges on both ends, directly bolted to pipeline flanges for reliable sealing and easy installation, especially suitable for high-pressure and large-diameter applications.
Compared to wafer-type butterfly valves, flanged versions do not rely on pipeline flange compression, offering higher sealing stability and independent disassembly for maintenance.
Valve Body Design
Manufactured via casting or forging to ensure sufficient strength and rigidity to withstand pipeline medium pressure.
Streamlined internal cavity design minimizes fluid resistance and turbulence, enhancing flow capacity and reducing energy consumption.
Disc Structure
The disc is a circular or elliptical thin plate that rotates around its axis to control medium flow.
Materials include stainless steel, copper, nylon, rubber-coated, or PTFE, selected based on operating conditions.
High-end designs use double or triple eccentric structures to eliminate friction, extend service life, and adapt to extreme conditions (e.g., ultra-high temperature/pressure).
Sealing Types
Soft Seal
Materials: Nitrile rubber (NBR), EPDM, fluororubber.
Features: Excellent sealing but limited temperature resistance (≤65°C), suitable for low-temperature/low-pressure applications (water, gas, oil).
Applications: Water supply/drainage, HVAC, food/pharmaceutical industries.
Hard Seal
Materials: Stainless steel or cobalt-based hard alloy welded onto seat/disc sealing surfaces.
Features: High-temperature resistance (≤550°C), high-pressure (up to PN25+), long lifespan, but slightly inferior sealing compared to soft seals.
Applications: Harsh conditions in chemical, oil, and steam pipelines.
Composite Seal
Structure: Laminated metal sheets (e.g., flexible graphite + stainless steel).
Features: Combines advantages of hard and soft seals, adapting to high-temperature, high-pressure, and corrosive media.
Applications: Heating, gas, oil, and acid/alkali pipelines.
Working Principle
Opening/Closing Control
The disc rotates 0°–90° around the stem to allow or block medium flow.
When fully open, the disc thickness is the only resistance, ensuring minimal pressure drop and excellent flow control.
Sealing Mechanism
Soft Seal: The seal ring elastically deforms under medium pressure to seal against the disc.
Hard Seal: Double/triple eccentric designs separate the seat and disc during operation to eliminate friction and achieve zero leakage.
Application Scenarios
General Conditions
Water/Power Plants: Control water flow and prevent leaks.
Chemical Industry: Regulate flow ratios of corrosive media.
Food/Pharmaceutical: Ensure medium purity and avoid contamination.
Special Conditions
High-Temperature/High-Pressure: Steam pipelines in oil/metallurgy.
Corrosive Media: Acid/alkali pipelines or seawater systems (use corrosion-resistant materials like stainless steel or PTFE-lined).
Bidirectional Sealing: Pump discharge check valves to prevent backflow.
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