Selection of control valve type
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I work in the process industry, so I may not know much about instruments. I would like to ask everyone: regarding valves of the type that use a valve core for regulation, which ones have high sensitivity in terms of regulation, such as ball valves, butterfly valves, globe valves, etc.?
All control valves have flow curves, typically including fast opening, equal percentage, and linear types. The choice of type depends on the process requirements; equal percentage should be selected for automatic control.
Choosing different flow curves (usually rapid opening and equal percentage) results in varying sensitivities at different opening degrees; for example, rapid opening is more sensitive at low opening degrees, while equal percentage is more sensitive at high opening degrees
If high sensitivity is required for automatic regulation at low flow rates, a control valve with linear characteristics should be selected.
For control valves, there are generally no butterfly valve types; they are mostly ball valves. However, gate valves do come in butterfly valve form. Overall, butterfly valves have higher sensitivity because their opening and closing radius is smaller than that of ball valves
Regulating valves also include disc valves, which are widely used in water treatment systems and the chlor-alkali industry. The choice of valve generally depends on factors such as the properties of the material, flow coefficient, and flow characteristics. Currently, equal percentage and linear methods are most commonly used, as these two flow characteristics offer high linearity and rapid response. Additionally, the adjustment sensitivity also depends on the PID parameters.