Selection issues for control valves
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On a process pipeline, the medium is an alkaline solution. The normal flow rate is 9231.12 Kg/h, the pressure before the valve is 1.86 Mpa, the pressure after the valve is 0.55 Mpa, the operating temperature is 38, the operating density is 1153 Kg/m3, and the dynamic viscosity is 1.8 MPa·s. That’s about it for the conditions. Since I have just started working, I don’t know much about this. So, how should I choose a control valve? What type should I pick? I know that to select the right valve, it’s necessary to determine the flow coefficient Cv value. But to calculate Cv accurately, it’s first necessary to roughly select the valve type in order to obtain some initial parameter values. So how should I make my choice? And how should I determine the maximum and minimum flow rates? I hope fellow sailors can help; it would be best if the details were provided
Determine the material first, and then find a supplier to help you work out the cost
The Cv value can be calculated using some software; high precision isn’t required – the parameters you provided are sufficient. The valve diameter is then selected based on the calculated Cv value. The maximum and minimum flow rates should be specified; after making the selection, it is advisable to ensure that the normal flow rate falls within the range of 40%-70% of the valve’s opening degree.
If there is a P&ID diagram, it is possible to tell from the diagram whether it is a straight-through valve or a rotary valve. (Butterfly valves are typically used for larger pipe diameters.) Straight-through valves come in single-seat, double-seat, or three-way types ； Rotary valves mainly refer to butterfly valves or eccentric rotary valves. Find a calculation software from a certain manufacturer, such as KOSO or FISHER, and first select a valve type to calculate the Cv value. If the flow characteristics of this valve type (linear or equal percentage) also meet your control requirements, and if it can satisfy the needs for fast opening and closing as well, with no issues in terms of stroke verification, then it’s pretty good. Just trying to spark some discussion