What is the difference between butterfly valve and ball valve?

Rotary valves are used to control the flow of many different liquids and gases over a range of temperatures and pressures. This group of valves includes poppet and plug valves, as well as the more popular and widely used ball valves and butterfly valves. The latter two are usually preferred as they are low cost, durable and reliable.

Given their function, it makes sense that they are also called control valves because they restrict or allow substances to flow through pipes. The type you choose depends on what you do and the specific control valve characteristics you need.

In this article, we'll take a deep dive into the differences between ball valves and butterfly valves, and the pros and cons of each, so you can understand how to choose the right component for your product.

What is a butterfly valve?

Butterfly valves are metal discs mounted on a rotating shaft, and like ball valves, they are quarter-turn rotary valves used for throttling. When the disc is perpendicular to the fluid, the valve is closed and flow is restricted. When it rotates 90 degrees, it opens and allows liquid or gas to flow.

Advantages of Butterfly Valves

Butterfly valves are lightweight and easy to operate, have a compact design, and are available in a variety of sizes, including very large, to meet the needs of your specific application.

Other advantages include low pressure drop and high pressure recovery, high flow coefficients, good control capabilities and openness to reduce plugging.

Butterfly valve application

Butterfly valves are widely used in chemical, agricultural, water and wastewater treatment services, and since they are also available in small size, they are very effective in areas where space is limited.

Typical applications include cooling water and air; fire protection; mud service; high pressure, high temperature water and steam applications, and vacuum service.

Butterfly valves also tend to cost more than ball valves because some types of valves require additional control to function. For example, if you choose a high-performance butterfly valve, the cost will increase significantly.

What is a ball valve?

Essentially, a ball valve is a quarter turn rotary valve, which means you turn it 90 degrees to fully open or close it. It consists of a ball with a hole that stops, allows or slows the flow of a fluid or gas through a pipe, depending on the direction of its rotation.

Advantages of using ball valves

Ball valves are easy-to-use components with relatively low cost. They are excellent at maintaining and regulating large volumes, high pressures and high flow rates, making them versatile for many different types of applications.

Ball valves are also durable enough to provide years of reliable service, and they are easy to repair or replace. For these reasons, and the fact that they provide a tight seal with little leakage when fully closed, they are one of the most widely used types of rotary valves.

A note on ball valve pressure: The ball valve will turn regardless of the pressure from the supply side. Also, if the diameter of the hole through the valve is the same (or larger) than the diameter of the supply pipe, there will be little restriction or pressure drop when fully open.

Application of ball valve

Ball valves are typically used for high pressure gas or liquid lines, approximately 15 cm in diameter or less, that require complete shut-off.

Typical applications include air, gas and liquid applications requiring hermetic sealing; steam services; water services and systems, and low point drains and high point vents in liquid and gas services.

Compared to butterfly valves, ball valves offer better shut-off characteristics in high pressure applications. They also continue to turn easily without the need for a pressure equalization scheme.

Once you have the basics down, you should have enough information to make the right choice when choosing a valve. Whichever you choose, make sure you choose a high-quality, reliable product that will maintain the integrity of your project.