Addressing Ball Valve Limitations

You’re probably already familiar with the benefits of ball valves, but do you know how to get ball valve functionality and customized fluid compatibility without flow restrictions?  If not, you’re not alone.

General Ball Valve Limits

When ball valves were initially introduced in the 50’s they were optimized for shutoff applications, frequent on-off service, instantly large flow processes  (i.e. safety systems or cooling water systems), and systems where the pressure drop across the valve is expected to remain fairly constant (i.e. steady state systems).

In addition to its strengths, ball valves in general share inherent limitations. Across all styles, ball valves have known issues with stem leakage, seat leakage, high pressure recovery, stops not properly set or operators not mounted correctly. In addition, they are difficult to clean, which is why ball valves are not recommended for pharmaceutical, bioprocessing, or food and beverage applications. Because ball valves are basically go, no-go devices, they tend to also be lousy regulators unfit for permanent throttling. And its poor throttling characteristics make ball valves prone to cavitation which is why ball valves are commonly found in flowing systems on ships, fire safe protection services and chlorine manufacturers.

Specific ball valve styles have their additional problems. Floating ball valves, for example, encounter issues with high friction and hysteresis.  Segmented and trunnion style ball valves suffer from limited differential pressure.

Overcoming Ball Valve Limits

While the limitations and constraints of ball valves are well known, alternatives are not. Today, not only are there options, but additional benefits such as more configurable pressure, improved machine control solutions and a consolidation of multiple valve functions into one. EVSCO, for example, offers many different flow solutions to support engineering design.

Stack Valve Advantages Not an Option for Ball Valves

Stack Valves are modular systems that combine multiple control functions into a single assembly. Its improved design offers the flexibility to combine similar or dissimilar flow options with a single actuation. In one assembly you could now combine a broad choice of valves, configurations, actuation, and flow styles.

To accommodate the most complex OEM requirement, multiple flow paths with a single, manual, electric or pneumatic actuation are controlled in one operation system. These valves can be configured in parallel, but because they are modular, they allow for any 90 degree port mounting configuration to help eliminate space and ease design.

This functionality allows designers to include any combination of the 2-Way, 3-Way, 4-Way, and 5-Way flow paths in one stack valve system operated by one actuator. As a result, a single actuator driving two valves will improve performance and reduce costs.

EVSCO Modular Stack Valve Systems offer ball valve functionality, in-line cleaning and servicing, a choice of O-ring materials and inert valve body material. Stack valves eliminate the need to design around constraints, space limitations without flow restrictions and volume.  Its unique flow configurations enables the selection of the most appropriate valve for the most efficient system design. Each valve is air-tested under water before shipment for long life and trouble-free operation.

While ball valves have their advantages in specific situations, they are not always the optimal choice. So before replacing or specifying your ball valve, evaluate your options. Many alternatives might have been overlooked in the past or available but unknown. There are also many new entrants that were not previously in existence that could be the optimal valve for you.

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