Metal seated ball valve noisy/ Juddering

[Anant64]

Dear all,
We have pneumatic actuated metal seated - Starline ball valve with Rotork CP actuator. 4 inch, reduced bore- 900# rating with CP - 250 actuator. The valve while opening & closing is noisy- juddering sound. Actuator is separately tested & works smoothly. Valve tested without controls - results are noisy operation. When we apply oil on the Ball sides the noise subsides & it works smoothly & again becomes noisy after few open close cycles. Air pressure min 5 bar & max 8.5 bar & noise remains.
Does this mean due to lubrication valve is making noise & is juddering. Or there is something else at play. Appreciate if any one have faced similar problem & have solution.
Download link of videos attached - we transfer.

https://we.tl/t-P0JKkLb4LM

https://we.tl/t-bpmMSkCjnv

Thanks,
Anant

 

[mk3223]

Sorry , not able to open the links.

For reference, we once had a ball type control valve with air operated actuator which had a "squeaking" sound while opening or closing. After the valve packing replaced, the valve operated smoothly without any trouble.

 

[aiyadude]

1. It could be the valve torque is high and the actuator is undersized.
2. Ball and Seat itself might be damage.
3. Remove actuator and try to stroke it manually and see if there is any issue.

Cant comment much as no video.