Daily Question on Automation Theory Knowledge (7.29)

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Process and instrumentation are inseparable; to help everyone gain a better understanding of the basics of instrumentation, we have launched the \"One Question per Day\" campaign – just reply to get the answers. To encourage continued participation from everyone! Get a wealth reward just by participating! I hope everyone will participate actively, learn together, and make progress together! ! ! True or False: 15. Is it correct that the flow characteristic curves of control valves include fast-opening, linear, equal percentage (logarithmic), and parabolic types? The answer to this question is: Yes. (1) Linear characteristic refers to the fact that the relative flow rate of a valve is in a linear relationship with its relative opening degree; in other words, the constant change in flow rate that occurs per unit change in opening degree. (2) The logarithmic characteristic means that a change in the valve opening by one unit results in a relative flow change that is proportional to the relative flow at that point; in other words, the amplification factor of the control valve varies, increasing as the relative flow increases. (3) The parabolic characteristic refers to the fact that the change in relative flow rate resulting from a unit change in relative opening is proportional to the square root of the relative flow rate value at that point. (4) The quick-opening flow characteristic refers to a high flow rate at low valve openings; as the opening increases, the flow rate quickly reaches its maximum, and further increases in opening result in only minor changes in flow rate, which is why it is called a quick-opening characteristic. The flow characteristic of diaphragm valves is close to that of quick-opening valves; the flow characteristic of butterfly valves is close to that of equal percentage valves. The flow characteristic of gate valves is linear, while that of ball valves is linear during the stages of partial opening and closing, and equal percentage at intermediate openings.