Understanding Butterfly Valves Functions, Types, and Benefits

Butterfly valves are a class of quarter-turn rotational motion valves designed to stop, regulate, or start fluid flow in pipelines. These valves are widely used due to their lightweight construction, cost-effectiveness, and quick operation. The term "butterfly" refers to the disk/flapper inside the valve, which is connected to a rod. When the rod rotates the disk by 90 degrees, the valve either opens or closes, allowing or stopping fluid flow. Butterfly valves can be operated manually using handles and gears or automatically via actuators or motors.

Applications of Butterfly Valves

Butterfly valves are extensively used across various industries due to their efficiency and ease of operation. Some common applications include:

• Water supply and distribution
• Wastewater treatment plants
• Pumping stations
• Chemical processing plants
• Power generation facilities
• HVAC systems

These valves are particularly suitable for:

• Constant Load Applications – Ensuring a consistent flow of fluid.
• Space-Restrictive Applications – Their compact size makes them ideal for tight spaces.
• Throttling Applications – Used to regulate fluid flow efficiently.
• Specific Pressure-Used to isolate low and medium pressure medium(soft seat)

Components of a Butterfly Valve

1. Valve Body: Fits between two pipe flanges, with the most common designs being lug and wafer types.
2. Disk (Butterfly): Controls the flow of fluid; variations in design optimize sealing, flow, and torque.
3. Valve Stem: Can be a one-piece or two-piece shaft, designed to prevent galling between corrosion-resistant materials.
4. Valve Seat: Provides shutoff by forming an interference fit between the disk edge and the seat. It can be bonded & vulcanized, pressed, or locked into the body.

Types of Butterfly Valves

Butterfly valves are classified based on different factors such as disk closure design, connection design, actuation method, and seat material.

1. Based on Disk Closure Design

• Concentric Butterfly Valve
• Eccentric Butterfly Valve Single-Offset Double-Offset Triple-Offset

2. Based on Piping Connection

• Lug Type
• Wafer Type
• Flanged Type
• Butt-Welded

3. Based on Operation Method

• Manual Actuation Lever Operated Gear Operated
• Automatic Actuation Electric(motorized) Actuated Pneumatic Actuated Hydraulic Actuated

4. Based on Seat Material

• Soft Seated (Rubber-lined for improved sealing)
• Metal Seated (For high-temperature and high-pressure applications)

Advantages of Butterfly Valves

Butterfly valves offer numerous benefits over other valve types, including:

• Compact and space-efficient design
• Lightweight and easy to install
• Cost-effective due to fewer raw materials
• Quick operation with low torque requirements
• Minimal pressure drops and high-pressure recovery
• Long service life and low maintenance requirements
• Suitable for large-diameter applications
• Excellent rangeability between 30:1 and 100:1

Butterfly Valve vs. Ball Valve

While both butterfly and ball valves are quarter-turn valves used for controlling fluid flow, they differ significantly in structure, operation, and application.

Butterfly valves are designed with a disk mounted inside the valve body, while ball valves use a spherical closure element to control fluid flow. One of the key differences between the two is the pressure drop; butterfly valves typically have a higher pressure drop compared to ball valves, which allow for smoother flow with minimal resistance. In terms of sealing effectiveness, ball valves provide a tighter shut-off, making them more effective for applications that require complete flow isolation.

Another distinction lies in weight and space requirements. Butterfly valves are significantly lighter and require less installation space, making them a preferred choice for large-scale flow applications and throttling. Conversely, ball valves are heavier and need more room for installation. Cost-wise, butterfly valves are generally more affordable due to their simpler construction and lower material requirements, whereas ball valves tend to be more expensive.

When it comes to application, butterfly valves are ideal for regulating flow in large-diameter pipelines and throttling applications, while ball valves excel in providing tight shut-off in critical systems where leakage prevention is essential.

At Bell Oil & Gas, we partner with leading OEMs to deliver a wide variety of high-quality valves, including butterfly and ball valves. Our Valve Asset Management Plant is fully equipped to repair valves of all sizes. Additionally, we provide onsite repair services for operational efficiency.

In the near future, we will proudly introduce a Made-in-Nigeria valve, manufactured by Nigerians, from our advanced production plant. Trust us for top-tier valve solutions designed to meet your industrial needs. Contact us today to discuss your requirements! Send a mail to [email protected]