What is a Butterfly Valve?

What is a butterfly valve? In short, butterfly valves are quarter-turn rotational valves used in pipelines primarily for flow shut-off. They’re widely used across water supply, distribution, and pumping applications, offering reliable flow isolation. Their simple, compact design makes them lighter, more cost-effective, and quicker to actuate than many other valve types. They are usually categorised into two types, but what are they?

Lugged and Tapped Butterfly Valves

A diagram explaining the main characteristics of a lugged & butterfly valve.

The most distinctive feature of this valve style is the series of threaded lugs on the body. Typically, the valve would sit between two flanges, but it can also be used as an end-of-line service. The lugs are used to bolt the valve to the flanges on a system. They are manufactured to be compatible with actuators, both pneumatic and electric(Edit)

Valves can also be used with actuators, levers or gearboxes.

Wafer Type Butterfly Valves

A diagram explaining the main characteristics of a wafer-type butterfly valve

Wafer-type valves are also bolted between flanges but do not include threaded lugs. Unlike lugged & tapped valves, wafer-type valves cannot be used as end caps, but can be used with actuators

Process Suitability

Butterfly valves are a versatile product suitable for use across the oil & gas, chemical, HVAC and water industry, among others. You’ll find butterfly valves suitable for almost any process media.

Common Butterfly Valve Questions

How does a butterfly valve work?

A butterfly valve works by rotating a central disc to control flow. In the open position, the disc turns to let fluid pass through, and when closed, it pivots across the pipe to stop the flow.

Are butterfly valves bi-directional?

Most butterfly valves are built to operate bidirectionally, allowing flow in either direction. However, certain systems may favour a specific flow direction to reduce torque, increase efficiency, and extend the valve’s service life.