Butterfly valves are a crucial component in fluid handling systems across a wide range of industries, including water treatment, HVAC, oil and gas, food processing, and chemical manufacturing. Known for their simple design, compact size, and cost-effective performance, these valves regulate flow using a rotating disc inside the valve body. Understanding the types of butterfly valves is essential for selecting the right valve for your specific application and achieving optimal efficiency and reliability. You can explore a full range of quality options at Types of butterfly valves for various industrial uses.
At their core, all butterfly valves operate with a disc mounted on a rotating shaft. When the valve is closed, the disc blocks the passage of fluid; when it is open, the disc rotates a quarter-turn to allow flow. What distinguishes the types of butterfly valves is how the disc interacts with the seat and how the valve is installed and operated. Let’s explore the main categories and their unique advantages.
The most common and cost-effective variety is the concentric butterfly valve, also known as a zero-offset valve. In this design, the shaft is centered in the middle of the disc, and the disc is centered within the valve body. The seat typically surrounds the disc and is made of rubber or elastomer, providing a tight seal when the valve is closed.
These valves are ideal for low-pressure and low-temperature applications, such as water distribution, irrigation, and some chemical services. They’re simple, reliable, and easy to maintain, though they’re not suitable for high-pressure or high-temperature conditions due to the limitations of their soft-seat materials.
The double-offset butterfly valve moves the shaft slightly off-center from both the disc and the pipe’s centerline. This design reduces wear and friction between the disc and the seat during operation. As a result, these valves can handle higher pressures and temperatures and have longer service lives compared to concentric types.
Double-offset valves are often used in systems requiring precise flow control, such as power generation plants, petrochemical facilities, and HVAC systems. They offer better sealing capabilities and less torque for operation, making them efficient and durable in demanding environments.
The most advanced and robust of the types of butterfly valves is the triple-offset butterfly valve. It features three distinct offsets: two from the shaft and one angular offset, which ensures that the disc contacts the seat only at the final point of closure. This eliminates friction, reduces wear, and allows for bubble-tight sealing even under extreme conditions.
These valves are designed for high-pressure, high-temperature, and critical applications, including steam systems, chemical processing, and offshore oil platforms. The metal-to-metal seal construction enhances their durability and allows them to function where other valve types would fail. They also meet many international standards for safety and performance in critical operations.
In addition to offset classifications, types of butterfly valves are also defined by their body styles and connection methods. Lug-style butterfly valves have threaded inserts (or lugs) that allow the valve to be bolted to pipe flanges on both sides. They can be removed independently of the system, which is useful for maintenance or replacement.
Wafer-style butterfly valves, by contrast, are designed to be sandwiched between two pipe flanges. They are held in place by the bolts that run through the flanges, making them lighter and more cost-effective. However, they must be removed by disconnecting the piping system, which can be a drawback for some users.
Flanged butterfly valves feature integral flanges for direct connection to piping systems, typically using bolts. They provide a secure and leak-proof seal and are ideal for larger pipe diameters or systems that undergo frequent disassembly and reassembly.
Butt-welded butterfly valves are permanently welded into the piping system. This type is used in high-pressure applications where a strong, seamless connection is required, such as in power plants and industrial process lines.
Another way to categorize the types of butterfly valves is by their method of actuation: