How many types of butterfly valve are there?

There are several types of butterfly valves, each designed for specific applications, operating conditions, and performance requirements. The main types of butterfly valves include:

1. Concentric Butterfly Valve: This is the most common type of butterfly valve, characterized by a circular disk centered within the valve body. The disk rotates around the centerline of the valve shaft to open or close the flow passage. Concentric butterfly valves are suitable for a wide range of applications and offer good sealing performance.

2. Eccentric Butterfly Valve: Eccentric butterfly valves have a slightly offset or eccentric disk, which allows the sealing surface to be positioned away from the centerline of the valve shaft. This design reduces wear and friction on the sealing surfaces and provides a tighter seal, making eccentric butterfly valves suitable for high-pressure and high-temperature applications.

3. Double Offset Butterfly Valve: Double offset butterfly valves feature both a shaft offset and an offset in the geometry of the sealing surfaces. This design minimizes friction and wear between the sealing surfaces during operation, resulting in improved sealing performance and longer service life. Double offset butterfly valves are commonly used in applications requiring tight shutoff and high-performance capabilities.

4. Triple Offset Butterfly Valve: Triple offset butterfly valves have multiple offsets in the geometry of the sealing surfaces, including shaft offset, eccentricity, and cone angle. This design provides a bubble-tight seal even in high-pressure, high-temperature, and abrasive media applications. Triple offset butterfly valves are often used in critical and demanding applications, such as oil and gas, petrochemical, and power generation industries.

5. High-Performance Butterfly Valve: High-performance butterfly valves are designed to meet stringent performance requirements, such as tight shutoff, high-pressure capability, and extended service life. They may incorporate features such as metal-to-metal seating, laminated seals, or special coatings to enhance sealing performance and durability.

6. Wafer Butterfly Valve: Wafer butterfly valves are lightweight, compact valves designed for use in low-pressure applications where space and weight are limited. They are installed between flanges using bolts or studs and are suitable for applications requiring quick and easy installation and removal.

7. Lug Butterfly Valve: Lug butterfly valves have threaded or bolted lugs around the valve body, allowing them to be installed between flanges without the need for nuts or bolts on both sides of the flange. This design provides ease of installation and maintenance and is often used in applications where frequent disassembly is required.

These are the main types of butterfly valves, each offering unique features and advantages suited to different applications and operating conditions.