Selection of control valves and flow meters
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This is a clumsy device; now it is necessary to select the control valve and the flow meter. I have just started working with chemical process instruments. I hope I can get some help with everything I don’t understand. Regarding the control valves on the drawings, how should I choose the right type for them? Regarding flow meters, under what circumstances should a mass flow meter be used and when should a vortex flow meter be used? Can a pneumatic single-seat control valve combined with Xuzhou Aka’s ZDP2000 electrical positioner be used for the control valve in the diagram? Since it is an old project, all control valves and flow meters need to be removed from the discarded equipment.
The selection of control valves takes into account factors such as the medium, temperature, pressure, and flow rate; therefore, re-calculation is required before making a selection
There’s actually no need for too much complexity when it comes to projects that involve reusing existing components; there’s no need to calculate everything in detail, as the results might not be useful after all… If the diameters are similar and the Cv values are roughly the same (even if they differ significantly, it’s still possible to use them), then just use them as is. The control performance might not meet expectations, but this can be compensated for through appropriate algorithms! The valve can be used with a reduced diameter, but it is best not to use it with an increased diameter. . . . As long as the flow meter is within its specified range and meets the installation requirements, there will be no problems.
The original poster had better compile the following on their own: 1. Flow meter parameters (such as diameter, temperature and pressure resistance, electrode material, lining material); 2. Parameters of the fluid being measured (such as medium type, flow range, temperature, pressure); 3. Valve diameter, valve type, valve Cv value, and the valve’s resistance to pressure and temperature. Try not to dump a bunch of mixed materials out
Main pressure ratings and CV value sizes.
Whether it is possible to reuse existing components depends mainly on the production process conditions. Control valves do not have standard designs like manual valves; they need to be recalculated based on the specific requirements of your process – it’s not sufficient simply to match the diameter. Mass flow meters can basically measure all types of media, but they may not always be suitable for use; it depends on the flow rate and whether it meets the requirements. Vortex flowmeters should not be used to measure materials that are too viscous or dirty; whether they are suitable or not also depends on whether the flow rate falls within the designed range
It’s necessary to check the parameters of the original control valve and compare them with the current process parameters in order to determine whether it can be used; I’m not sure about the flow meter
Main pressure ratings and CV value sizes.
There are too few parameters, and it’s hard to tell what function you’re trying to implement. Regarding flow meters, it is necessary to consider your actual operating conditions, as well as your existing flow meters (range, tolerance to temperature and pressure, etc.)