Butterfly valve switching issue
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On the dial of a butterfly valve, it is still possible to turn it further in the closing direction even after it has been set to 0; can this indicate a problem with the valve, or is it sufficient to turn it to 0 to consider the valve fully closed?
Is it a mechanical scale or an electrical signal display from the control cabinet? If it’s a mechanical scale, as long as the deviation isn’t too large, i.e., within 5%, you can simply reposition the scales. If the electrical signal display is inaccurate, it can be corrected using a multimeter; a scale range of 0-100 corresponds to 4-20 milliamps, so adjustment can be made on a proportional basis
It has mechanical scales; does the handwheel need to be rotated until it can no longer move to achieve complete shutdown?
If it’s a mechanical display, is it the turbine box? Generally, at the beginning or end, there is first a turbine clearance; only after going through these steps is the actual stroke completed
That’s correct; I test it that way on-site.
This post was last edited by Butterfly Valve Specialty Store on 2012-11-14 at 15:27. The handwheel needs to be rotated until it can no longer move in order to achieve a complete shutdown; there is a slight margin of error allowed.
That mechanical pointer can rotate; you need to check whether it has moved 90 degrees