Ball Valves: A Comprehensive Guide to Types and Applications

author: ATHENA GROUP

2023-08-22

A ball valve features a spherical disc to open and close the flow of the fluid. As a result of their design, they guarantee very tight and leak-free sealing even after years of operation. Floating valves and trunnion valves (side or top entry) are the two main types of ball valves. A ball valve's body can be cast or forged, and monolithic or split (in two or three pieces). API 6D and ASME B16.34 are the key specifications.

What Is a Ball Valve?

A ball valve is a type of quarter-turn valve that uses a hollow, perforated, and pivoting ball to control the flow of liquids or gases through a pipeline or system. The ball inside the valve has a hole through its center, which, when aligned with the flow path of the pipeline, allows the fluid to pass through, and when rotated 90 degrees, blocks the flow by closing the hole.

Advantages and Disadvantages of Ball Valves

This type of valve has the following advantages:

Provide a very tight seal without having to apply excessive torque to ensure a very tight seal.
With the turn of a quarter, the door can be quickly opened and closed.
Despite being both on/off devices, ball valves have a compact design (this is the most significant difference between ball valves and gate valves.

The disadvantages are:

Designed for pipeline shut-off rather than flow modulation (this is an ideal function for globe valves), this valve has poor regulating and throttling capabilities: throttling causes the partially exposed seat to erode due to the high flow and pressure it experiences. As a result of wear, the valve may leak gradually.
The valve cannot be used for slurries as suspended particles and debris may solidify in the cavities near the ball and seats and cause the valve to leak. Gases and liquid fluids (even challenging chemicals such as dry chlorine, hydrofluoric acid, hydrochloric acid, and oxygen) can be handled much more efficiently with ball valves.
Depending on the design, cleaning may be a challenge (except for the top entry design).

Ball Valves: How Do They Work?

Ball valves operate through a straightforward yet effective mechanism that involves a hollow, perforated ball positioned within the valve body. This ball can be rotated using a stem connected to an external handle or actuator. The ball has a hole, or bore, drilled through its center, and its position determines whether fluid can flow through the valve or not.

Here's how ball valves work:

Open Position:

When the ball valve is in the open position, the bore of the ball is aligned with the flow path of the pipeline. This allows the fluid to pass through the valve without obstruction. In this configuration, the valve offers minimum resistance to the flow of liquids or gases.

Closed Position:

When the ball valve is rotated by 90 degrees, the bore of the ball becomes perpendicular to the flow path, blocking the passage for the fluid. In the closed position, the ball acts as a barrier, preventing the flow of liquids or gases through the valve. This position ensures a tight seal, reducing the risk of leakage.

The lever or actuator attached to the stem of the ball valve provides a visual indicator of the valve's position. When the lever is parallel to the pipeline, the valve is open, and when it is perpendicular to the pipeline, the valve is closed. Any angle in between indicates a partially open or partially closed position, allowing for some flow control.

Ball valve vs gate valve

Essentially, this valve is a gate valve, which shuts off flow. The difference between a ball valve and a gate valve is that the former opens/closes the flow with a spherical ball, while the latter opens/closes the flow with a disc sitting on a seat. This means that these two valves differ in design and compactness.

Ball valve vs globe valve

As these valves are generally positive (at 0, 45 and 90 degrees) rather than incremental positions, they are not as precise at controlling fluid flow as globe valves. The valve would also be damaged if it were partially opened (or repeated open/close operations) over time (which is not a problem with globe valves).

Types of Ball Valves

Ball valves exhibit a diverse classification based on several distinguishing factors:

1. Design:
Ball valves encompass various design categories, including the floating design, trunnion mounted configuration, and the double bleed and block design.

2. Number of Ports:
These versatile valves come in multiple port arrangements. The standard variant comprises two ports, catering to a single inlet and outlet. However, the 3-way design offers distinct possibilities, featuring one inlet and either two outlets or vice versa.

3. Bore Size:
Bore size choices further define ball valves. This entails the option of a full bore (FB) or a reduced bore (RB), with the inclusion of the V-notch configuration.

4. Body Assembly:
The assembly of the valve body results in varied configurations. These include the unibody design, characterized by the ball body being crafted from a single piece of cast or forged steel. Alternatively, the valve body can take the form of two pieces or three pieces, achieved through the assembly of separate components.

5. Ball Access:
The accessibility of the ball within the valve structure is another parameter of differentiation. The options here are the side entry approach or the top entry approach. This distinction hinges on whether maintenance access to the ball is obtained from the valve's side or its top.

6. Seat Type:
The type of seat integrated into the valve plays a pivotal role. Choices here encompass both metal and soft (Teflon) variations, each offering distinct advantages and attributes.

In summary, the realm of ball valves is marked by a spectrum of classifications based on their design, port configurations, bore sizes, body assembly methods, ball access mechanisms, and seat types. This array of options caters to diverse applications and operational requirements across a multitude of industries.

Forged Steel Floating Ball Valve

Introducing the Forged Steel Floating Ball Valve, expertly designed with a compact two-piece structure, making it ideal for medium/low pressure operations. Its streamlined build accommodates a small diameter, ensuring efficient performance. Notably, the valve seats are seamlessly integrated into the body, enhancing durability and simplicity.

Distinguished by its ingenious design, the valve's free-floating ball is propelled against the downstream seat by upstream flow pressure. This innovative mechanism guarantees leak-free sealing, maintained over years of service due to the resulting compression. The top-mounted stem facilitates easy quarter-turn movement, ensuring swift valve operation.

We are Athena Engineering S.R.L, a renowned specialist in the field of ball valves. As prominent valve manufacturers based in Italy, we excel in delivering top-notch solutions. For any inquiries or requirements, please don't hesitate to reach out to us at sales@athenavalve.com. We are here to cater to your needs with expertise and precision.