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Choosing Pilot-Operated Control Valves Over Direct-Acting Control Valves


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Control Valves

In various industrial sectors like oil and gas, chemical processing, and water treatment, control valves are vital components for regulating fluid and gas flow. These valves enable precise control of processes, optimizing efficiency and safety. Two commonly utilized types of control valves are direct-acting control valves and pilot-operated control valves. In this article, we will delve into the advantages of pilot-operated control valves, comparing them to their direct-acting counterparts.


Understanding Pilot-Operated Control Valves

Pilot-operated control valves represent a more sophisticated version of direct-acting control valves, engineered to deliver improved accuracy and responsiveness in flow control. Both types operate based on the same principle, with a valve plug or disc modulating flow in response to changes in the process variable (e.g., pressure, flow rate, or fluid level). However, their key differences lie in how the valve is being actuated.


In direct-acting control valves, the control signal (e.g., electric current, pressure, or flow) directly operates the valve opening/closing. Conversely, pilot-operated control valves utilize a smaller pilot valve to govern the actuation of the main valve.


Advantages of Pilot-Operated Control Valves

Pilot-operated control valves are known to be more accurate in their ability to regulate pressure/flow of a system as compared to their direct-acting counterparts. The use of a pilot valve in pilot-operated control valves allows for fine-tuning of the main valve's position, providing enhanced precision in regulating the flow of fluids or gases. This level of control enables pilot-operated valves to maintain a more consistent and precise flow rate, making them particularly suitable for processes that require strict adherence to specific setpoints.


In comparison to direct-acting control valves, pilot-operated valves experience less friction and wear. The smaller size and lower actuation forces of the pilot valve alleviate mechanical stress on valve components, resulting in a longer service life and reduced maintenance requirements, leading to cost savings.


Pilot-operated control valves exhibit versatility across a broad spectrum of applications, including high-pressure and high-flow scenarios. Their design equips them to handle larger flow rates and pressures more effectively than direct-acting valves while maintaining the use of the same type of pilot valve. As a result, pilot-operated control valves serve as ideal solutions for diverse industries with varying operational needs.


The pilot-controlled actuation ensures enhanced stability during fluctuating process conditions. Pilot-operated valves facilitate smooth and gradual opening or closing of the main valve, minimizing the risk of abrupt pressure changes or flow instabilities that can lead to water hammering and potential damage to systems.


Choosing your control valves

Pilot-operated control valves present several distinct advantages over their direct-acting counterparts, making them the preferred choice in numerous industrial applications. With their accurate control, high flow capacity, wide pressure range, and increased reliability, pilot-operated control valves provide a reliable solution for optimizing process control. While both types of control valves have their merits, pilot-operated control valves stand out as an excellent choice for critical systems that demand accurate and dependable fluid controls.


We at Val-Technik would be able to provide professional opinion on the appropriate setups for pilot-operated control valves and suggest optimal sizing for the valves to function effectively in piping systems.


For more information and consultation regarding the different types of pilot-operated control valves and their suitability for a system, please email us at sales@val-technik.com.sg or call 6742 2770.



References

https://www.valvemagazine.com/articles/solenoid-valves-direct-acting-vs-pilot-operated




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