Ball Valve vs. Butterfly Valve – A Deeper Look At Pros & Cons

Ball Valve vs. Butterfly Valve – A Deeper Look At Pros & Cons

Valves are fluid control devices that are used to manage the flow of media in a piping system. This involves directing, controlling and regulating flow. There are various types of valves that, though they perform the same function of fluid control, are of different builds or best suited for different applications.

This article comparatively explores ball valves and butterfly valves, two of the most commonly used quarter-turn valves. The following explains their construction, mode of operation, applications, benefits, and limitations, before analysing the different scenarios in which each valve will be best suited.

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Ball valves

Ball valves are quarter-turn valves that are either manually controlled or automated using electrical or pneumatic actuators. Ball valves operate using a horizontally hollowed-out sphere/ball to control flow. The ball swivels on the vertical axis and is connected to an externally located lever via a stem.

The lever is used to control the valve. It also indicates the position – open or closed – of the valve at any given time. As ball valves are quarter-turn valves, i.e. the ball can only turn 90°. When the hole is perpendicular to the flow direction, the valve is closed, and the ball's solid portion shuts off the flow. On the other hand, when the valve is open, the hole is aligned with the flow path, allowing the fluid to flow through.

Ball valve

However, ball valves do not operate in open and closed positions only. These valves can be set to partially open/partially closed positions using the lever. This feature of ball valves makes them suitable for not only blocking/permitting flow, but also for regulating it.

Types of ball valves

There are numerous types of ball valves that can be classified according to different categories. Some of these are as follows.

By number of ports

While most ball valves are 2-way, i.e., having two ports, there are also 3-way and 4-way ball valves that serve different circuit functions. 3-way ball valves rank immediately after their 2-way counterparts in terms of ubiquity. These ball valves typically have either L-shaped or T-shaped bores, allowing them to achieve circuit functions such as distribution and mixing of flows. 3-way valves are commonly referred to as T valves because of their semblance to the letter “T.”

3-way ball valve with manual lever

By ball design

Ball valves are also classified by ball design – into floating and trunnion valves. In the floating ball design, the ball is held in place by the valve seats. On the other hand, the trunnion ball design sees the ball also supported at the top and the bottom. The trunnion ball design is used for large diameter ball valves with high operating pressures.

By housing assembly

Another category for classifying ball valves is the housing assembly. The housing, which is the main valve body that encloses the ball, may be one-piece, two-piece, or three-piece. One-piece valve housings are a single unit. While these are the least expensive, they cannot be disassembled for repair or cleaning.

On the other hand, two-piece valves can be dismantled. However, they have to be disconnected from the pipe to do this. Lastly, three-piece pipes are made of different pieces that are bolted together. The centre section of these valves can be disassembled or removed without having to uninstall the end connections from the pipe.

By build variation

Apart from the loosely defined standard ball valve construction, some ball valve types may have certain extra features for specific purposes. One such type is the vented ball valve. At first glance, vented ball valves look like regular ball valves. However, these valves' balls feature a small orifice drilled into the solid portion of the valve.

This feature allows pressure or any trapped medium to escape when the valve is closed. It is critical in high-pressure and extreme temperature applications.

Vented ball valve

Ball valves also vary by connection ports. A ball valve may have a threaded, welded, flanged, tri-Clamp, or true union connection.

Applications of ball valves

Ball valves are used in countless applications across various industries. This wide usage results from their availability in a wide range of builds, sizes, and materials and their excellent control abilities. They can be used for start/stop operations, as well as mixing, directing, and regulating flow.

These valves have numerous domestic and industrial uses and can be found in gas plants, water systems, industries, refineries, distilleries, homes, and many others.

Benefits of ball valves

Ball valves are quick-acting, requiring only a 90-degree turn to completely open or close.

They provide tight sealing, completely preventing the flow of media once in the closed position.

They allow for precise and reliable flow regulation

The spherical build of the stopping mechanism allows it to withstand high pressures

When in the fully open position, ball valves rarely cause pressure drops as the ball doesn't interfere with the flow

A ball valve will always turn, regardless of the inflow pressure

Limitations of ball valves

Ball valves are relatively expensive

They are larger and heavier than their counterparts of the same capacity, making it impossible to use them in certain scenarios.

Butterfly valves

Like ball valves, butterfly valves are quarter-turn valves that control the flow of the medium. These valves may be manually controlled or automated using actuators. The closing mechanism in a butterfly valve is an upright, flat, circular disc that turns on the vertical axis.

The disc is usually attached concentrically or eccentrically to the top and bottom of the valve, with the stem running along the disc's side. The stem extends out of the valve, where it is connected to the controlling lever.

Butterfly valve

Butterfly valves turn by 90°, moving from the fully open to the fully closed positions and vice versa. The disc's turning motion resembles the motion of a butterfly's wing, hence the name “butterfly valve.”

When the valve is fully open, the disc is perpendicular to the flow direction, with the thin edge of the disc facing the flow. On the other hand, when it is fully closed, the disc's flat face aligns with the flow, completely blocking it.

Butterfly valves can be placed in partially open/partially closed positions, but this is used more for reducing flow rate than precise regulation.

Types of butterfly valves

There are various types of butterfly valves that each combine a set of features. As a result, butterfly valves can be classified according to different categories, using these features.

By disc design

Based on disc design, butterfly valves can be classified as concentric and eccentric. Concentric butterfly valves are more common, with the stem passing through the disc's centreline. These valves are also known as zero offset valves. On the other hand, in eccentric butterfly valves, the stem doesn't pass through the disc's centreline.

Eccentric butterfly valves may be single offset, in which the stem is located directly behind the centreline; double offset, in which the stem is placed behind the disc, but with an extra offset along the lateral axis of the disc; and triple offset, in which there is an additional offset between the disc and the seat contact axis.

By build

Butterfly valves are of different builds, with the major difference between them being the mounting features. The most common butterfly valve builds are lug butterfly valves and wafer butterfly valves. The lug variants feature threaded lugs around the valve flanges. These lugs are used to connect the valve with bolts. Wafer valves, on the other hand, do not have attachment lugs. Instead, they are sandwiched between pipe flanges.

Applications of butterfly valves

Butterfly valves are sought after due to their versatility and functionality. They come in a wide range of sizes. Butterfly valves can be found in industrial plants, wastewater processing plants, water supply systems, and many others.

Benefits of butterfly valves

Butterfly valves are quick-acting, requiring only a 90-degree turn to completely open and completely close.

They provide good open/close control.

They are cheaper than ball valves of the same capacity

Because of their design, butterfly valves are smaller and lighter than their ball counterparts. This makes it easy for them to fit into tight spaces and complex circuits

Limitations of butterfly valves

They do not provide 100% sealing and are relatively leak-prone

By design, the disc is always in the flow path. While the interference may be minimal, it still has the potential to result in a pressure drop

Butterfly valves are not suitable for high-pressure applications as the disc is unable to reliably withstand such pressures.

There are inflow pressure limits above which the valve may fail to turn.

Ball valves vs. butterfly valves

Both ball and butterfly valves are used in a wide range of applications. These quarter-turn valves are used to control the flow of fluid in piping systems. They are available in numerous materials, including brass, PVC, stainless steel, steel, copper, etc.

Butterfly valves provide good start/stop control. For applications in which only this is required, butterfly valves are sufficient. When cost is a major consideration, butterfly valves are the better option. However, their relatively fragile build makes them unsuitable for high-pressure applications. They are also not suitable in applications requiring precise control as they may leak. For such applications, the sturdy build of ball valves makes them a better choice.

On the other hand, ball valves are relatively large and cumbersome compared to butterfly valves of the same capacity. This makes butterfly valves great for tight spaces.

A Quick Comparison Between Ball And Butterfly Valves

Valves are used by engineers to control the flow of liquid and gas for different applications. Valves help regulate the flow at any temperature, velocity and pressure. The two types of valves commonly used in industries are butterfly valves and ball valves.

Wafer valves: Wafer valves are standard valves installed with nuts, studs or bolts between two flanges. It is less expensive than lug valves and is an excellent option if you do not want to disconnect a side of the piping system.

Lug valves: Lug valves are used for applications that require temporary fixtures. It uses threaded metals as inserts to hold the bolt of the valves. Hence, nuts are not required. A set of bolts secures both sides of the flange. Such a design offers more flexibility as you can leave one side of the piping system untouched and still disconnect the other side.

Butterfly valves are lightweight and resemble a butterfly wing. It comes in one- or two-piece designs. Valves with a one-piece design will have a disk placed on a shaft that rotates a pipe. A two-piece valve allows full flow with the sections held inward and lies flat as it gets closed. Butterfly valve manufacturers in India design two different types of butterfly valves, namely:

What Is A Ball Valve?

A ball valve has a floating ball that has a hole through it. The hole will block, open or partially block the flow of gas and liquid when the valve gets activated. The tight seal of ball valves is ideal for a system that requires gas flow. These valves are used for high-pressure application of both gas and liquid lines of six inches and lesser diameter. It can operate at temperatures ranging from -30 degrees to 230 degrees. Even if the supply side has high pressure, it offers no resistance when you turn the valves. Different types of ball valves manufactured in India include:

V-port Ball Valve:

These valves will have a V-shape seat or ball. It ensures a stable flow from the small end of the V to the wide end. V-port ball valves are the best choice when there is a high velocity or you require more control on the flow. They are sturdier and withstands high velocity compared to other types of valves.

Full-port Ball Valve:

These valves offer no loss of friction as the hole inside the ball is of the same size as the pipeline.

Trunnion Ball Valve:

The ball is fixed to the bottom and top of this valve. It is used in high pressure or large-scale application wherein it prevents issues with the seating mechanism and the ball from floating away.

Cavity Filler Ball Valve:

This type of valve is mostly used in the healthcare and food industry because the cavity plugs prevent any residue build-up and contamination.

Reduced-port Ball Valve:

In these valves, the hole inside the ball is smaller than the pipe, restricting the flow. It is the least expensive valve.

Difference Between Ball Valve And Butterfly Valve

Based on the project, you need to select the ideal valve considering factors like the quality of seal, pressure difference, or pipe size. There are applications where you can use either of the valves; in such cases, the choice will be based on availability and pricing. However, other applications have specific valve design requirements. If we look at the similarities, both valves can turn 90 degrees and control the flow. That’s about it. There are some subtle differences in the characteristics and applications of the two types of valves. The differences are:

Butterfly valves are used for water-based systems for low-pressure applications, while ball valves are mostly used for gas-based applications with varying pressure and temperature.

Butterfly valves have a simpler design, are lightweight and cost less. Ball valves can have simple to complex designs, and the price will vary accordingly.

Butterfly valves either have flanged ends or can be installed sandwiched between pipe flanges. Ball valves, too, have flanged ends but with socket, threaded, ringed glove, RTJ, tube, sanitary tri-clamp and cam lock.

As the leading industrial valve suppliers in India, we produce high-quality industrial valves by maintaining utmost consistency and following the latest production practices. Please do contact our customer executives, to learn more about the different types of valves we produce.

Differences Between a Ball Valve & a Butterfly Valve

Ball valves and butterfly valves are both quarter-turn (90-degree turn from fully opened to fully closed) rotary valves. The family of rotary valves also includes cone and plug valves. They are used to control the flow of most types of gases or liquids across a wide range of temperatures and pressures. Butterfly and ball valves are both popular for their relatively low cost, long service life and dependability. However, there are a few differences to help the user choose between them.

Ball Valves

A ball valve is (in simplest terms) a ball with a hole running through it. Turning the valve positions the hole to either block, partially block or complete the line of flow through the valve.

Advantages of ball valves include a good seal, or little to no leak-by when the valve is fully closed. A ball valve will turn regardless of the pressure on the supply side. If the hole through the valve is as large or larger than the supply pipe inner diameter, the ball valve will offer essentially no pressure drop or restriction when fully opened.

Ball valves are often used in high pressure liquid or gas lines, usually 6 inches or less in diameter, where a complete cut off is important.

Butterfly Valves

A butterfly valve is a disk mounted on a rotating shaft. When fully closed, the disk completely blocks the line. When fully opened, the disk is at a right angle to the flow of gas or liquid.

One of the advantages for butterfly valves is that they are relatively inexpensive to build and maintain. They are the most common valve for large volume water systems such as municipal water works. They can be used for dirty liquid applications such as sewage or controlling river water.

The butterfly valve disk is still in the valve flow line when fully open, so there will always be a pressure drop across a butterfly valve. Also, if the pressure difference across the butterfly valve is great, it may be difficult to open the valve. Some applications require a bypass valve to bring the pressure difference down before large butterfly valves can operate.

Differences

Butterfly valves are less expensive and generally lighter weight than other types of valves. A butterfly valve for a large diameter pipe is much smaller than its ball valve equivalent.

Butterfly valves do not seal as completely as ball valves and are rarely used to control gas flows. Ball valves provide a reliable seal.

In high pressure applications, the ball valve will provide superior cut-off characteristics as well as having no trouble turning or needing a pressure-balancing scheme.