Understanding the design, functionality and configurations of 3-way ball valves
In fluid control systems, understanding how a 3-way ball valve works is crucial for optimising performance, safety and space efficiency. 3-way ball valves offer unique advantages over traditional two-port configurations. Their ability to divert, mix or shut off flow between multiple ports makes them invaluable in industrial applications where space optimisation, operational safety and versatility are key. Bonomi Industries, a global leader in the production of high-performance flow control components, including ball valves, offers highly engineered three-way valves designed to exceed standard market requirements, both in terms of performance and construction quality.
Core components of 3-way ball valves
Before delving into the operating principles of 3-way ball valves, it's important to identify the key mechanical components that form the basis of their function. All ball valves, including three-way configurations, share the same fundamental components:
- Body: the main pressure-containing structure, often made of brass, stainless steel or other robust materials. In RuB valves, the body is precision-machined for tight tolerances and excellent sealing.
- Stem: connects the handle or actuator to the ball and enables its rotation.
- Sealing system: comprising seats and O-rings, seals ensure fluid-tight operation. Bonomi Industries utilises high-quality materials to maximise chemical compatibility and pressure resistance.
- Thread connections: valves’ terminals are threaded for standard pipelines.
- Handle or actuator interface: manual versions are fitted with a lever, while versions with ISO 5211 flanges can be automated using pneumatic or electric actuators.
How 3-way ball valves work
Having examined the core mechanical components of a three-way ball valve, it's important to understand how these elements work together to control flow. A 3-way ball valve functions by rotating a perforated ball inside the valve body to redirect flow between three different ports. The orientation of the ball bore determines which ports are connected. As the handle or actuator turns the stem, the ball rotates to align its internal passage with the desired ports. Depending on the port design (L-port or T-port), the valve can either divert the flow from one inlet to two possible outlets or mix flows from two inlets into a single outlet.
Flow configurations in 3-way ball valves: L-port vs T-port
Building on the basic operating principle described in the previous section, it's important to explore how internal flow configurations impact the functionality of a 3-way ball valve. These functional differences in three-way ball valves are defined by the internal bore of the ball, which governs how the media flows between ports. This configuration determines whether the valve will serve a diverting or mixing role, giving rise to the two primary types: L-port and T-port designs, each tailored to specific application needs.
L-Port design (diverting function)
The L-port design, named after the L-shaped bore within the ball, is a type of 3-way ball valve used specifically for diverting applications. It allows the fluid to be directed from one inlet to one of two outlets. This configuration is commonly used when a system requires the flow to be directed between two separate lines. A typical example would be diverting flow to one of two tanks.
RuB S.7600 series is a 2-seat valve with L-port geometry. These valves perform a 90° rotation to alternate the flow direction. There is no “off” position — at any given time, one inlet and one outlet are connected. Thanks to their simplified internal structure with only two seats and one end-cap, RuB valves reduce the number of potential leakage points compared to traditional three-seat models on the market.
T-Port design (mixing or distributing function)
The T-port configuration demonstrates another way a 3-way ball valve works—either mixing two inlet flows or distributing flow to two outlets. It can connect all three ports simultaneously, mix fluids from two inlets into one outlet, or distribute flow from one inlet to two outlets, depending on the ball orientation.
The RuB S.7300 series by Bonomi Industries exemplifies this configuration. These 4-seat valves offer multiple flow paths and up to 180° or 360° ball rotation, making them suitable for complex mixing or distribution applications. Unlike many competitors, Bonomi Industries integrates the actuator flange directly into the body, complying with the ISO 5211 standard, eliminating the need for mounting brackets and reducing installation space.
Two-seats vs Four-seats design in 3-way ball valves
When evaluating how a 3-way ball valve works, the number of seats in the valve is a crucial factor influencing both performance and application suitability. Bonomi Industries offers two distinct designs in its range of 3-way ball valves: the 2-seat configuration (S.76 series) and the 4-seat configuration (S.73 series), each tailored to specific flow control requirements.
- 2-seat valves (S.76 series): featuring a straightforward design, these valves are optimal for flow diversion tasks. Their compact size, cost-efficiency and dependable performance make them ideal for standard industrial operations involving L-port flow paths.
- 4-seat valves (S.73 series): built for more demanding applications, these valves support complex flow patterns such as T-port configurations. The four-seat design enhances sealing integrity and allows for more precise control in multi-directional systems.
A key innovation that sets Bonomi Industries apart in the 3-way ball valve market is the single end-cap design. Unlike most competitors who use three endcaps—each adding potential leakage points—RuB valves feature only one. This significantly minimises the number of sealing interfaces, improving overall reliability, reducing the risk of leakage, and lowering maintenance demands over the valve's lifecycle.
Operational options: manual and automated 3-way ball valves
A key aspect in understanding how a 3-way ball valve works lies in its actuation method. Bonomi Industries provides both manual and automated options, offering flexibility for a wide range of industrial applications. The wide selection of available configurations can be explored within the dedicated RuB valves product line, which includes 3-way ball valves and actuator-ready models.
- Manual version with lever: ideal for straightforward on-site control, this configuration allows operators to manually rotate the ball to achieve the desired flow path, whether diverting or mixing.
- Actuator-ready version: designed with an integrated ISO 5211 flange, these 3-way ball valves can be easily connected to pneumatic or electric actuators. This simplifies installation and enables remote operation or automated control in high-cycle or hard-to-access environments.
By offering both actuation types within its 3-way ball valve product line, Bonomi Industries ensures seamless integration into complex systems while maintaining the performance and reliability required in critical fluid control scenarios.
If you're looking for a high-quality solution and want to learn more about how a 3 way ball valve works in your specific application, get in touch with the Bonomi Industries technical team today. We're here to help you find the ideal configuration for your system's needs.