Can a butterfly valve be used as a control valve? And, if so, what is the correct application? The answer depends on the application and the amount of money allotted for your project, as well as other variables that can change from project to project. So, what is the right application for butterfly control valves? Let’s take a closer look.
A Choice Between Cost and Accuracy
Before deciding on the type of control valve to put in your application, consider:
- What is the application?
- How much control is required?
- What is your project budget?
A butterfly valve works well as a control valve and doesn’t cost as much as a globe style valve or other type of control valve, but only if your application can accept limited accuracy. The conditions of your processes often dictate the type of butterfly control valve needed, such as resilient seated or high-performance. Other aspects that influence this decision to use a butterfly valve for control purposes include:
- Less expensive installation costs
- Smaller physical size which means each valve costs and weighs less.
- Lower profile/weight means you can use fewer braces and supports
- More compact sizing and fit
- Have fewer parts and are easy to maintain
Limitations of Butterfly Valves as Control Valves
A butterfly control valve won’t be suitable for every application and shouldn’t be chosen simply to cut project costs. These valves have limits. For instance:
- Most butterfly valves have a flow characteristic that’s essentially closed until it’s opened to a 40-degree angle: Between a 40-degree and 80-degree angle, flow dramatically increases from 20% to 90% of capacity or more. The movement isn’t precise, and the inability to turn down appropriately means a butterfly valve often isn’t fit for applications that require precise control.
- Butterfly control valves’ recovery factors are typically poor compared with a conventional control valve. They often have cavitation issues and experience permanent pressure drop as they throttle flow.
- It’s challenging to reach exact control that you can repeat: This is especially true with low flow rates.
Summary: When Is It OK to Use Butterfly Control Valves?
While butterfly control valves aren’t suitable for every process application, such as those requiring exact control, you shouldn’t discount them altogether.
Butterfly control valves are perfect for applications where there isn’t much space. These valves offer throttling and regulation of flow while a butterfly control valve’s pressure loss is much less than that of a Globe valve.
In the majority of applications, a butterfly control valve can take the place of other control valves because they:
- Offer nearly the same essential functions
- Have more safety features
- Perform better
A butterfly control valve in your applications can:
- Minimise the need for maintenance
- Provide accurate, stable, modulating flow control
- Reduce disaster risks, such as leaks
Overall, yes, butterfly valves can be used in applications requiring control. In fact, it could mean a significant difference in project costs. Book an appointment or reach out to us on Facebook to learn more about using butterfly control valves in your next project.