When the pneumatic butterfly valve is closed, it experiences severe vibration
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On-site, there is a pool with a height of six meters, and at its bottom there is a pneumatic butterfly valve for drainage, which is opened and closed regularly. It is discharged into a gutter, using an open-drain system with almost no consideration given to system backpressure. When the valve is opened, everything is normal; however, severe vibration and noise occur when it is closed. The vibration should occur 1-2 seconds after the valve is fully closed; I would like to know why this happens
This should be checked to examine the positioning – one is the positioning adjustment bolt of the valve body itself, and the other is the limit adjustment on the actuator. Oh, and the sealing of the valve ports.
I checked all the limit bolts of the cylinder; there are no issues. The valve seals are in good condition as well, and no water flows when it is closed. Could it be that the exhaust from the cylinder is too rapid, causing vibration? I installed a damper at the exhaust port of the solenoid directional valve – would this help improve the situation?
Add two small throttle valves to the exhaust port and try adjusting the exhaust speed. The pipes might be vibrating too fast
1 When a fluid medium is in motion, it possesses kinetic energy; when the flow pattern changes rapidly and the flow stops, all of this kinetic energy is converted into pressure energy. The liquid impacts the valve disc, resulting in vibrations. The greater the fluid density, the longer the pipe, the higher the initial flow velocity, and the faster the valve is closed, the more pronounced the water hammer effect becomes. When all other conditions remain unchanged, extending the time taken to close the valve can significantly reduce the severity of water hammer
The butterfly valve experiences fluttering, which may affect its performance over time.
There may be water hammer; it is recommended to change the valve closing time. As you suggested, install a flow restrictor on the cylinder exhaust.
Vibration is normal when shutting down; there is a throttling effect during this process, the flow rate decreases gradually, which leads to a sudden increase in pressure in the pipeline and thus vibration
The shutdown speed is too fast, causing water shock.