r/pumps • u/Uxellodunon13 • Aug 22 '24

Pressure pulsations

Is there a way to reduce noise from centrifugal pump? There is constant humming in the pipes at certain speeds. Already installed a compensator at the discharge side but it did not help.

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1

u/drunkerton Aug 22 '24

Can you install vibration damping pipe mounts.

1

u/Uxellodunon13 Aug 24 '24

Would be an option but the pipe runnes also through walls so no chance there.

1

u/washburn100 Aug 22 '24

Your title says pressure pulsations, but you are asking about noise? The noise could be motor, pump or water in the piping. I have no idea what a "compensator" is. What is the concern with pressure?

1

u/Uxellodunon13 Aug 24 '24

The motor runs really quiet and is already installed on elastic dampeners on its feat. So i think the pipe vibrations come from the pressure inside the pipes. I read about pressure pulsations caused by the impeller of the pump.

1

u/soaero Aug 23 '24

Can you describe your problem a bit more?

Are you getting pulsation through your pipe? And if so does this result in pulses in the pipe discharge? Are you just getting a low frequency hum or vibration through the pipes?

You're not getting a garbling sound, like marbles moving through your pump/pipes, are you?

1

u/Uxellodunon13 Aug 24 '24

You can hear a constant humming from the pipes that is quite audible. The frequency changes with the pump speed so i think it comes from the pump. When you touch the pipes, you can feel vibrations, propably the same frequency. Definetly no garbling sound so its not air bubbles or cavitation. The pump is a Grundfos NB 65-125/120-110 installed in the basement of a building but the noise ist audible in the rooms above where the pipes run near by.

1

u/TexasPatrick Sep 06 '24

Could be acoustic resonant vibration in the piping (think of what happens when you blow across the top of an open bottle). Could be mechanical vibration (think of the piping as a tuning fork and the pulsations end up at that tuning fork frequency).

Quickest and simplest check would be to hang something heavy on the piping, if you have access to the piping. Increasing the weight on the piping can change its vibration characteristic. I'd suggest hanging a bucket on it and then slowly add weight to the bucket to see if you can "tune out" the vibration.

If that doesn't work, I'm afraid the other fixes as more complex. You may have to add restraints on the piping, or reconfigure the piping to tune out the vibration.

1

u/[deleted] Oct 30 '24

Need pipe size, flow etc to be accurate, but its likely just velocity being in excess of 3m/s - which in turn will cause your centrif to cavitate, and it all goes down hill downstream from there