Vibration in control valve opening? ?
Thread Content
This post was last edited by wwxxss_1 on 2010-2-24 07:51. The opening degree of the control valve keeps changing; the indication on the on-site locator is completely normal, but the valve keeps shaking and fails to settle in position. For some reason, the valve is from Samson
It generally occurs on valves used to regulate flow! Valve positioners use mechanics
It is caused by an unstable output signal from the valve. Check whether there is a possibility of signal overlap in the output circuit of the signal, and verify that there is no repeated signal accumulation on a single output within the soft circuit. Or else, the driving force of the fluid flowing inside the pipeline is too high. This prevents the valve from closing.
Readjust the valve positioner.
How to set the valve positioner? Parameters or mechanical position?
I think what was said on the third floor makes a lot of sense; it’s about learning*, but I think you should also take the manufacturing process into consideration
It’s probably caused by an excessive pressure difference; check what type of pressure reduction method SAMSON uses. If the valve vibrates and its position fluctuates up and down, it won’t last long – within at most 2 months the valve core will be damaged. The issue of valve selection.
It might be due to the locator not being installed in an appropriate location
Vibration of the control valve. The fault symptoms and causes are as follows: 1. The control valve vibrates at any opening degree. ①Unstable support ； ②There is a vibration source nearby ； ③The valve core and bushing are severely worn. 2. The control valve vibrates when it is near the fully closed position. ①If the control valve is chosen to be too large, it is often used at a low opening degree ； ②In a single-seat valve, the flow direction of the medium is opposite to the closing direction. I don’t know what the problem is on site; you should check these aspects first!
1. If it is in automatic adjustment mode, it may be due to changes in the control signal input; instability in the process environment should also be considered. 2. If the control output current remains stable, then it might be because the instrument air pressure isn’t properly adjusted, and this can very likely cause disturbances in the valve operation. 3. There is a problem with the air circuit of the positioner; impurities in the instrument air flowing through it can also cause disturbances in the valve. 4. It is also necessary to consider the size of the cylinder’s valve… In such cases, it is important to check whether the selected actuator is suitable. Wait, wait... Hehe... There could be many reasons
There might be a problem with the valve positioner; another possibility is that the pressure difference is too large!