Valve Insights Blog

Specifying Control Valves for Severe Service Applications

Written by Christian Conesa | Mar 6, 2025 2:00:00 PM

Control valves in severe service applications face extreme operating conditions, including high pressures, extreme temperatures, corrosive substances, and abrasive media. Traditional control valves often fall short, leading to frequent maintenance, performance issues, and costly downtime. Specifying the right control valves ensures long-term reliability and their ability to withstand the harshest conditions.

Understanding Severe Service Application Demands

Severe service conditions subject control valves to challenges like cavitation, flashing, and noise, which are often the result of high fluid velocities and major pressure drops.

  • Cavitation occurs when local pressure drops below the fluid’s vapor pressure, forming bubbles that collapse and erode valve surfaces downstream.
  • Flashing happens when vapor bubbles travel downstream without collapsing, carrying abrasive particles that damage valves and piping.
  • Noise results from high fluid velocities and turbulence, leading to vibration, wear, and unsafe working conditions.

Another severe service phenomenon is choked flow, where fluid flow reaches a limit despite higher pressure. This condition increases cavitation and flashing risks, making it critical to specify valves that can handle extreme environments.

Key Considerations for Specifying Severe Service Control Valves

When specifying control valves for severe service, several design elements become essential for performance and durability.

Material Selection

Choosing the right materials is vital in harsh, high-temperature environments. Hardening processes like CVD-5B, a boron diffusion treatment, resist erosion and corrosion, tolerate temperatures up to 1200°F, and extend valve life. Trimteck’s valves also use alloys like Hastelloy, Monel, and titanium for resistance to chemicals and extreme temperatures.

Trim and Flow Control

In severe service, managing fluid flow within the valve reduces cavitation and noise. Multi-stage trims like Trimteck’s ST-2 and ST-3 handle high pressure by gradually reducing it across restrictive paths. This process prevents bubble formation, reducing erosion risks. The ST-3 trim also cuts noise by up to 30 dBA, minimizing pressure and turbulence.

For lower cavitation risk, Trimteck offers single-stage trims like the ST-1, which directs bubbles toward the cage center to protect valve surfaces.

Valve Seat and Seal Design

Valve seats must deliver a tight shutoff while withstanding erosion from high-velocity, abrasive flows. Trimteck’s ST-5 Venturi seat manages flashing by directing erosive force away from key components to replaceable sections. Similarly, our ST-4 stacked disc trim uses grooved discs to gradually lower pressure, providing erosion resistance for abrasive flows.

Valve Specification Software

Trimteck’s AccuValve™ software simplifies severe service valve specification by analyzing fluid properties, operating pressures, and flow rates to recommend optimal configurations. AccuValve’s™ features include:

  • Fluid property analysis: AccuValve™ calculates the cavitation index (Sigma) and noise potential, ensuring the valve and trim match specific conditions. It uses Sigma to identify cavitation risks and guides engineers to the ideal multi-stage trim.
  • Customized recommendations: Data-driven recommendations specify the trim type, materials, and valve size, extending operational life and minimizing maintenance. AccuValve™ follows ISA-RP75.23-1995 guidelines for precise, tailored choices.

30 Years of Control Valve Experience

With over 30 years of experience, Trimteck has become a leader in severe service control valves, helping industries like oil and gas, power generation, and petrochemical. Our team collaborates with clients to meet the unique requirements of severe service, equipping each valve with the best materials, trims, and designs.

To learn more about Trimteck’s severe service solutions or to explore how AccuValve can help you specify the ideal control valve, reach out to a Trimteck representative or try out our AccuValve software.