Is ball valve a control valve?

Have you ever wondered if the simple ball valve in your system can handle precise flow control tasks?

While ball valves are primarily designed for on/off operation, certain types can control flow. However, they are not ideal for precise throttling compared to true control valves.

Ball valve control function

I’ve worked with ball valves across various HVAC and plumbing projects. Many engineers ask if these valves can be used for flow control. Let’s break down the key characteristics and understand the limitations and use cases.

What is another name for a ball valve?

Have you heard people referring to ball valves by other names and felt unsure if they’re talking about the same thing?

Another name for a ball valve is a shut-off valve¹ or quarter-turn valve. These names reflect the valve’s function and quick operation method.

Different names, same valve

Ball valves are simple and widely used, so they have earned different names in various industries. In my experience, the two most common alternative terms are:

People sometimes casually refer to them as isolation valves because they are used to stop flow quickly. The term quarter-turn valve emphasizes how you can fully open or close the valve with a simple 90-degree turn of the handle.

In some specifications or catalogs, you might even see the term “ball-type valve.” Regardless of the name, the key feature is the spherical ball inside the valve body that rotates to control flow.

When I walk into a mechanical room and see a valve with a lever handle, I usually assume it’s a ball valve unless marked otherwise. Recognizing these alternative names ensures you’re clear when selecting or discussing valves with contractors or suppliers.

Can you control water flow with a ball valve?

Do you think adjusting the handle slightly can effectively control water flow?

Yes, you can control water flow with a ball valve by partially opening or closing it. However, they are not designed for precise flow regulation and may wear faster under throttling conditions.

Ball valves and flow control limitations

In many projects, I’ve seen ball valves² used to control water flow temporarily. Their design allows the internal ball to rotate, opening the passage partially and restricting flow. While this seems convenient, it comes with trade-offs.

Here’s why ball valves aren’t ideal for precise flow control:

While it’s possible to adjust flow roughly using a ball valve, I avoid this practice for long-term solutions. The valve’s seats and seals are optimized for full open or closed positions. Leaving the valve half-open accelerates wear and reduces lifespan.

If you need fine-tuned control over flow rates, I always recommend using a globe valve or a dedicated control valve instead. These valve types are designed to handle continuous throttling without degrading performance.

That said, in emergencies or temporary setups, I’ve used ball valves to limit flow in smaller pipelines. But I always switch to proper control valves when accuracy and longevity are essential.

Can I throttle a ball valve?

Have you tried using a ball valve for throttling and wondered if it’s safe?

You can throttle a ball valve by partially opening it, but this is not recommended for sustained use. Continuous throttling can damage the valve’s seats, causing leakage and reduced lifespan.

Why throttling is risky for ball valves

Throttling means controlling flow rate by partially restricting the valve opening. Many technicians, including myself early on, have tried using ball valves for this purpose. But here’s what I’ve learned:

Ball valves are best suited for fully open or fully closed positions. Their seats are usually made from soft materials like PTFE. When the valve is left partially open, water flow erodes the seat material. Over time, this results in poor sealing and increases leakage risk.

In one industrial project, I saw frequent failures where ball valves were used to throttle cooling water flow. The seats degraded quickly, and replacement became costly.

For systems needing precise throttling, I recommend control valves³ or globe valves, which are designed with flow regulation in mind. However, if temporary throttling is unavoidable, stainless steel ball valves with metal seats can handle the stress slightly better.

Still, as a long-term solution, I advise against throttling ball valves due to their wear and reliability issues.

Why is it called a ball valve?

Have you ever wondered why this valve type is named after a ball?

It is called a ball valve because its main internal component is a hollow, perforated ball that rotates to control flow. The ball’s rotation aligns or blocks the passageway.

How the ball design works

The key feature of a ball valve is the spherical element inside the valve body. This ball has a hole drilled through its center. When you rotate the handle or actuator:

• Ball opening aligned with the pipe → Flow is fully open.
• Ball turned 90 degrees → Flow is fully blocked.

The simplicity of this design makes ball valves reliable and easy to operate. Below is a table summarizing the ball valve’s internal mechanism:

The reason why it’s called a ball valve is simple—the valve uses a ball-shaped disc as the control element. This design allows for quick shut-off⁴, low-pressure drop when open, and reliable sealing.

When I explain ball valves to clients, I often compare their operation to a faucet handle. It’s straightforward—turn it a quarter turn, and the flow stops. This user-friendly nature makes ball valves popular in HVAC systems, water supply lines, and industrial setups.

The name reflects the function, making it easy for engineers and operators to understand how the valve works just by hearing its name.

Conclusion

Ball valves can control flow, but they are best used for on/off functions, not precise throttling. Understanding their limits ensures efficient, reliable system performance.