at one site the is abnormal sound from the actuators comparing to other actuators , note that these are installed on butterfly valves
any one can knows the reason ?
Type of actuator, - electric, air, hydraulic, spring return??
speed of actuator?
Manufacturer of actuator?
Model of actuator?
Do the valves close against flow or isolate a stationary flow?
what is an "abnormal sound"?
what is a normal sound?
what are the other actuators - different in any way?
does the sound come from the actuator or the valve?
How do you know?
How old is the equipment,
Have you asked the vendor?
What other investigations have you done?
Any pictures?
Any video / sounds able to be posted or linked to a you tube video?
Try to provide answers to that lot and then we might get somewhere
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
Pipe configurations near the valves.
What pipe sizes.
What valve sizes.
What is the flow rate and fluid velocity through each valve.
History of what maintenance was performed for each valve.
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