Daily Question on Automation Theory Knowledge (9.1)

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This post was last edited by 18663069001 on 2017-9-3 at 11:04. Process and instrumentation are inseparable; to help everyone gain a better understanding of the basic principles of instrumentation, we have launched the \"One Question per Day\" campaign – just reply to view it. To encourage continued participation from everyone! Get a 3-wealth reward just for participating! Higher rewards for correct answers! I hope everyone will participate actively, learn together, and make progress together! ! ! Multiple-choice question: 47. When a control valve is often operated at a low opening degree, it is advisable to choose a ( ) characteristic. A. Equal percentage B. Quick opening C. Linear D. Two-position. Hint: The main flow characteristics include linear, equal percentage (logarithmic), parabolic, and quick opening. 1. The 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, it is the constant by which the flow rate changes for each 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 situation in which a large flow rate is achieved at a small opening degree; as the opening degree increases, the flow rate quickly reaches its maximum value, and further increases in the opening degree result in only minor changes in flow rate, which is why it is called a quick-opening characteristic. The answer to this question is: A