Can the control valve be adjusted to any opening degree?
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When tuning control valves, we usually operate them through positions of 0, 25, 50, 75, and 100. However, the client requires that we be able to set the opening degree arbitrarily, for example at 5%, and if the valve does not respond, they claim that we have not done a proper tune-up. I would like to ask whether the smart locator allows the opening degree to be set arbitrarily
Of course, the opening degree can be set arbitrarily; 0, 25, 50, 75, and 100 are just conventional values used during debugging.
During debugging, the stroke was 0, 25, 50, 75, 100. The client requires 5%, so it’s necessary to check whether the valve operates
What does it matter? High-performance valve systems require calibration in increments of 0.5 valve positions
The customer's special requests should be met.
We have never requested it that way; usually it’s 0, 50, 100%, and 25, 75 – those options are rarely tried.
A valve position of 5% is used to test the sensitivity and dead zone of your valve; the opening degree can be set arbitrarily! As long as it is within the specified dead zone!
This post was last edited by FightingNow on 2015-12-22 at 17:44. Of course, the degree can be set however you like! …The several debugging sampling points are there to allow the valve to operate once, so that samples can be taken for analysis; if the valve positions at these points are all correct, then the valve should function properly! ! The deadband sensitivity of the valve can be adjusted using the valve positioner; it should not be too sensitive, nor too sluggish!
I thought about the dead zone of control valves, and I’m also confused! Can this thing actually be adjusted? Is it determined at the time of production? It’s a mandatory standard!
A small valve opening is indeed not good for the valve core
It can be adjusted to any opening degree, but there is one issue: when the valve is opened to a small degree, adjustment is affected by the dead zones present in both the actuator and the valve itself. If adjustments are to be made within the range of 5%-10%, then the quality of the valve stem’s construction and that of the actuator become important factors. If these two aspects are not of high quality, the valve’s adjustment performance will be poor. The adjustment performance of control valves is better within the range of 10%-90%, with 50%-60% being the optimal range for adjustment. Therefore, it is necessary to calculate the CV value in order to select the appropriate size for the valve stem. If the customer requires adjustments at small opening degrees, special attention must be paid to the valve stem and the actuator.