Process Engineering Division – Instrumentation and Automation Section – Daily Topics – Topic No. 2020-12-28
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Process Engineering Division – Instrumentation and Automation Section – Daily Topics – Topic No. 2020-12-28: Discussion question: 340. There is a split-range control system with two control valves; the tuning ratio for each valve is R1=R2=30. The maximum flow rate for the first valve is 100 m3/H, while that for the second valve is 4 m3/H. What is the maximum achievable tuning ratio? (5 points are given only to those who provide the correct answer; additional points are awarded for a correct calculation process or detailed explanation.)
There is a proportional control system with two control valves, whose adjustable ratio is R1=R2=30. The maximum flow rate for the first valve is 100 m3/H, while that for the second valve is 4 m3/H. What is its maximum adjustable ratio? Solution: The minimum flow rate for the first valve = 100/30 = 3.33 m3/H; the minimum flow rate for the second valve = 4/30 = 0.133 m3/H. The maximum adjustable ratio R = 100/0.133 = 752. Answer: The maximum adjustable ratio is 752.
The maximum adjustable ratio is the ratio of the maximum flow rate of the first valve to the minimum flow rate of the second valve, that is: 100*30/4 = 750
The minimum flow rate for the first valve is Q1min = 100/30 = 3.3 m3/h, while the minimum flow rate for the second valve is Q2min = 4/30 = 0.134 m3/h. Therefore, R = Q1max/Q2min = 100/0.134 = 740; thus, the adjustable ratio can reach 740.
The maximum adjustable ratio is the ratio of the maximum flow rate of the first valve to the minimum flow rate of the second valve, that is: 100*30/4 = 750
100*30/4= 750
The maximum adjustable ratio is the ratio of the maximum flow rate of the first valve to the minimum flow rate of the second valve, that is: 100*30/4 = 750
The maximum adjustable ratio is the ratio of the maximum flow rate of the first valve to the minimum flow rate of the second valve, that is: 100*30/4 = 750