What Is a Butterfly Valve and How Does It Work?

When it comes to fluid control systems, the butterfly valve is one of the most popular choices for both industrial and commercial applications. But have you ever wondered how exactly a butterfly valve works? Let’s break it down in a simple and practical way.

1. Basic Concept of a Butterfly Valve

A butterfly valve is a type of quarter-turn valve used to regulate or isolate flow. The name comes from its structure — a metal disc (like a butterfly’s wings) mounted on a rotating shaft inside the pipe. When the valve is turned 90 degrees, it opens or closes the flow of gas, water, oil, or other fluids.

Compared with gate or ball valves, butterfly valves are lighter, more compact, and quicker to operate. That’s why they’re often used in pipelines that require fast shut-off and frequent operation.

2. Main Components of a Butterfly Valve

A typical butterfly valve includes several key parts:

• Valve Body – The main casing that connects to the pipe.

• Disc – The rotating element that controls flow.

• Stem or Shaft – Connects the disc to the actuator.

• Seat – Provides sealing to prevent leakage.

• Actuator – Manual handle, electric motor, or pneumatic device that drives the valve.

Even though the structure seems simple, the material and design greatly affect the valve’s performance. For example, acid/alkali butterfly valves need corrosion-resistant materials, while cryogenic butterfly valves must perform reliably under extreme low temperatures.

3. How It Works

Here’s the fun part!
When you rotate the handle (or actuator), the disc turns around the shaft.

• When the disc is parallel to the flow, the valve is fully open — allowing fluid to pass freely.

• When it’s perpendicular, the valve is closed — blocking the flow entirely.

It’s super easy to control and adjust the flow rate, which is why butterfly valves are widely used in gas, water, steam, and oil pipelines.

4. Common Applications

Butterfly valves are versatile and used in:

• HVAC systems

• Chemical and petrochemical plants

• Water treatment facilities

• Power generation systems

• Marine pipelines

Depending on the medium, you can choose from gas butterfly valves, electric ventilation butterfly valves, or hydraulic check valves for safety and reliability.

5. Why Choose Shanghai Rogers Valve

Shanghai Rogers Valve Co., Ltd. provides high-quality industrial valves including Gas Butterfly Valves, Water/Steam/Oil Butterfly Valves, Acid/Alkali Butterfly Valves, Electric Ventilation Butterfly Valves, Cryogenic Butterfly Valves, and Hydraulic Check Valves.
All products are designed for durability, precision, and long service life — ensuring efficient fluid control for global customers.