I discovered a great new series of YouTube videos from the Emerson team managing the Fisher Valves & Instruments brand of products. Two of the three recent videos are part of the Control Valves Basics playlist which also has quite a number of other videos to quickly ramp you up the learning curve on basic knowledge of control valves.
The three new videos include:
- What Is a Control Valve? (2:04 runtime)
- What Are the Different Types of Control Valves? (3:31 runtime)
- What Are Control Valve Selection Criteria? (4:04 runtime)
Let’s recap the third one about control valve selection to give you a flavor for the content.
The video opens highlighting the fact that there are many styles of valves with many variations. The goal is to select the proper valve to reliably satisfy the requirements of its intended application. Having a flow coefficient is not sufficient to successfully select the right control valve.
From an economic perspective, it’s important not just to consider the upfront capital cost of control valves but to consider the entire lifecycle and life expectancy. Another selection consideration is maintenance schedule. Will there be routine shutdowns and if so, what are their frequency? The location of the valve and its accessibility need to be considered too.
Cost to maintain is another consideration as is the impact on the process if the valve were to fail, since this downtime may lead to lost revenue. Controllability is another consideration. How close to setpoint does it need to operate? Based on the processing characteristics is 10% good enough or does it need to be 1% or even ½%.
Another selection consideration is the applicable code requirements, such as the ASME B16.34 Valves—Flanged, Threaded, and Welding End standard and any industry-specific regulations. Materials of construction requirements may include NACE or ISO corrosion resistance standards. The specifics of the application and environment in which the valve will operate can add additional requirements.
It’s important to remember that no two processes are identical, even in the case of repeating units and plants. A successfully applied valve in one application will not necessarily be successfully applied in another very similar application. Improperly selected valves can struggle to maintain setpoint and have to work extra hard in trying. This can lead to quality issues, wasted feedstock and damage to the valve’s internals.
Work with your local Impact Partner or Emerson office to determine the best valve to meet the selection requirements for your application. Visit the Fisher Valves & Instruments section on Emerson.com for more on control valve sizing & selection, quote on valve parts, drawing and toolkits to help you successfully apply the right valve for the application.
