What type of valve cage design allows flow capacity to increase by an equal percentage with incremental changes in plug travel?

The equal percentage cage design is specifically engineered to allow for a flow capacity that increases by a constant percentage for equal increments of plug travel. This characteristic makes it particularly useful in applications where the flow must be finely controlled across a wide range of operating conditions. The design enables the valve to provide a non-linear flow response that gives operators the ability to make more precise adjustments, especially at low flow rates where traditional linear and quick-opening designs may not provide sufficient control.

In contrast, quick-opening cages cause the flow to increase rapidly for a small amount of plug travel, which can lead to less precision in control. Linear opening cages provide a uniform increase in flow capacity, meaning flow rate changes proportionally with plug movement, but do not account for the increasing demands of non-linear systems. Low-noise trim refers to designs meant specifically to reduce noise produced by the valve during operation and doesn’t focus on the flow coefficient relationship to plug travel.

Thus, the equal percentage cage stands out because of its ability to maintain consistent control across varying flow requirements by offering a predictable and scalable flow response.