High Noise Through Nitrogen Line-Increase Line Size??
High Noise Through Nitrogen Line-Increase Line Size??
(OP)
We are having noise problems near a nitrogen line that flows through a 2" pipe. The nitrogen goes through a presure reducing valve that causes the flow to be choked (80 psig coming in and 3 coming out of the valve). How could we reduce the noise? Would increasing the line size help reduce it? The flow is choked, so flow rate would not decrease if we increase the line size correct? This should decrease velocity and therefore decrease noise.
Thanks
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RE: High Noise Through Nitrogen Line-Increase Line Size??
In this case you must focus your efforts on reducing the single stage pressure drop ratio at the valve- your ratio of 95psia/18psia tells the whole story. Reducing the aerodynamic noise is usually done using staged trim, outlet diffuser, or both. Check with the representative of the valve to see what your options are. Increasing the line size will not help.
best wishes, sshep
RE: High Noise Through Nitrogen Line-Increase Line Size??
RE: High Noise Through Nitrogen Line-Increase Line Size??
example
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RE: High Noise Through Nitrogen Line-Increase Line Size??
RE: High Noise Through Nitrogen Line-Increase Line Size??
Hope this would help
Cheers
RE: High Noise Through Nitrogen Line-Increase Line Size??
The line size of 2" would seem to have a moderate cost for a two or even three stage set of regulators, i.e first regulator 80 psi drop to 20 psi, second regulator 20 psi drop to 3 psi. It might be less cost than staged trim in a single regulator.
Flow velocities over approximately 150 feet per second will tend to have more noise. The acoustical insulation on piping will reduce transmission of noise, as noted by liberoSimulation. Heavier wall pipe will also reduce the noise. The major noise source is in the regulator / control valve disk - seat area. The piping might generate some noise from flow turbulence in the pipe and fittings if velocities are high. That would be where a larger downstream pipe size would have benefit. Given the ratio of the pressure drop, the downstream pipe size could be 3" or 4", depending on mass flow required.
RE: High Noise Through Nitrogen Line-Increase Line Size??
Thanks.
RE: High Noise Through Nitrogen Line-Increase Line Size??
The noise is generated at the valve. If you took off the down stream piping you would still have the noise. You have to attack the problem where it is occuring to have an impact.
Stonecold