Making process control valve choices

Today’s process control valves offer an ever wider range of features and benefits

for industries that require precise control over fluids, steam and other gases. With so many control valves to choose from it is important to establish the

features that will deliver the most cost-effective design for a particular application.

Control valves are used to manage the flow rate of a liquid or a gas and in-turn control the temperature, pressure or liquid level within a process. As

such, they are defined by the way in which they operate to control flow and include globe valves, angle seat, diaphragm, quarter-turn, knife and needle

valves, to name a few. In most cases the valve bodies are made from metal; either brass, forged steel or in hygienic applications 316 stainless steel.

Actuators will use an on-board system to measure the position of the valve with varying degrees of accuracy, depending on the application. A contactless,

digital encoder can place the valve in any of a thousand positions, making it very accurate, while more rudimentary measurements can be applied to less

sensitive designs.