Connection Type
Lug
- Protruding lugs that have bolt holes to match with those in the pipe flange.
- Allows dead-end service or downstream piping removal.
- Threaded bolts around the entire area make it a safer option.
- Offers end-of-line service.
- Weaker threads mean lower torque ratings.
Wafer
- Without protruding lugs and instead sandwiched between the pipe flanges with flange bolts surrounding the body. Features two or more centering holes to help with installation.
- Does not transfer the weight of the piping system through the valve body directly.
- Lighter and more economical.
- Wafer designs do not transfer the weight of the piping system directly through the valve body.
- Cannot be used as a pipe end.
Double Flanged
- Complete flanges on both ends to connect with the pipe flanges (flange face on both sides of the valve).
- Popular for large size valves.
Body Material
Butterfly valves are typically made from a variety of materials, including:
- Cast iron: Durable, heavy and cost-effective, used in non-corrosive applications.
- Ductile iron: A type of cast iron that is more flexible and resistant to wear and tear, used in high-pressure applications.
- Steel: Strong, versatile and resistant to corrosion, used in high-temperature applications.
- Stainless steel: Resistant to corrosion, high-temperature, and rust, used in harsh, corrosive environments.
The choice of material depends on the operating conditions, such as temperature, pressure, and corrosiveness, as well as the desired cost, weight, and longevity of the valve.
Disc Material
The disc of a butterfly valve is one of the critical components that helps to regulate the flow of fluids. Different materials are used for the disc based on the type of fluid, pressure, temperature, and other environmental factors. The most common materials used for butterfly valve discs are:
- Ductile Iron: Ductile iron is a popular material for butterfly valve discs because of its high strength, good corrosion resistance, and low cost.
- Stainless Steel: Stainless steel is used for high-temperature and high-pressure applications, as it has good corrosion resistance, high strength, and durability.
- Aluminum Bronze: Aluminum bronze is a corrosion-resistant material that is well-suited for marine and chemical processing applications.
The choice of disc material depends on the specific application requirements, such as temperature, pressure, corrosiveness, and compatibility with the fluid being transported.
Shaft Material
The shaft of a butterfly valve is a critical component that transfers the torque from the valve handle or actuator to the disc, allowing it to rotate and open or close the valve. The material used for the shaft affects the strength, durability, and corrosion resistance of the valve. Common materials used for butterfly valve shafts include:
- Stainless steel: Resistant to corrosion, high-temperature, and rust, used in harsh, corrosive environments.
- 410SS - Standard on all iron body valves
- 316SS - Standard on all 316SS body valves
- 304SS - Standard on all 304SS body valves
Seat Material
The seat of a butterfly valve is the surface that seals against the disc to prevent fluid from leaking through the valve. The material used for the seat affects the performance, durability, and corrosion resistance of the valve. Common materials used for butterfly valve seats include:
- EPDM (Ethylene Propylene Diene Monomer): Resistant to heat, ozone, and chemical exposure, used in high-temperature and harsh chemical applications.
- NBR (Nitrile Butadiene Rubber): Resistant to oils and fuels, used in petroleum and petrochemical applications.
- Viton (Fluoroelastomer): Resistant to high temperatures and chemicals, used in high-temperature and harsh chemical applications.
- PTFE (Polytetrafluoroethylene): Resistant to chemicals and high temperatures, used in corrosive environments.
- Neoprene: Resistant to oil, ozone, and weather, used in industrial and marine applications.
- Silicon: Resistant to high temperatures and chemicals, used in high-temperature and corrosive applications.
- Hypalon: Similar to Nitrile and EPDM applications. Applications such as chloride, peroxide and acids.
The material selected for the seat of a butterfly valve has an impact on its performance, durability, and resistance to corrosion. The type of material used will depend on various operating factors such as temperature, pressure, and the presence of corrosive substances, as well as the required performance, cost-effectiveness, and longevity of the valve.
Actuator Types
Actuators are devices that control the movement of a butterfly valve, allowing it to open and close as needed. The following are common types of actuators used with butterfly valves:
- Manual Handles: Simple, manual devices that allow the valve to be opened and closed manually using a handle or lever.
- Gearboxes: Mechanisms that convert rotary motion into linear motion, used to drive the valve disc open or closed.
- Pneumatic Actuators: Devices that use compressed air to drive the valve open or closed, typically used in industrial and commercial applications.
- Electric Actuators: Devices that use electrical power to drive the valve open or closed, typically used in control systems.
- Hydraulic Actuators: Devices that use hydraulic fluid to drive the valve open or closed, typically used in high-pressure applications.
The choice of actuator will depend on the operating conditions, such as temperature, pressure, and corrosiveness, as well as the desired level of automation of the valve.
