Building an enclosure for the treatment plant air pump - ideas and tips?

[Tom]

Hi all. I've got to get round to building a soundproof enclosure for our treatment plant air pump as I'm fed up with the faint drone when I'm sat outside.

We've got a Conder, so the air pump currently sits under the main lid of the unit. I'm thinking I need to build a structure with some mass to prevent transmission of sound, so was thinking I'd pour a small slab, say 50cm2, then build a tiny enclosure with concrete blocks. I guess I'd include a short length of ducting up through the slab for the power and air hose. Is this the right way to go? I'm not sure what I'd use for a "door" on the front, or what to use as a roof - I have some (block and) beam offcuts so could use these to make a flat solid concrete roof perhaps, with some corrugated tin over the top.

Has anyone built their own enclosure, have any tips for what works well or even some pictures? 

Thanks all!

[ProDave]

Before you get too carried away, I quietened our Conder simply by placing a standard 100mm concrete block in the chamber so the pump sits on that now, not the plastic that it used to sit on.

 

Still not silent but a LOT quieter.

[JohnMo]

Ours is a separate box really noisy so buried the bottom part in soil - way less noise - most the noise is vibration induced.

[Gone West]

Our box was remote and designed to be half buried in soil. It was quiet if more than a metre away.

[Nickfromwales]

23 hours ago, Tom said:

with some corrugated tin over the top

Don't use this, as it will be thin enough to be a resonator / acoustic radiator. Concrete paving slab would be weathertight and have some weight to it to help out here.

[saveasteading]

It's poor if they haven't designed the pump to be quiet. It is probably cobbled in to the already designed tank as an afterthought, with plastic and screws.

I agree with the earth and concrete slab principle if that works.

[Alan Ambrose]

I'm wondering whether modulating the speed down, if that's possible, will make it quieter?

[Nickfromwales]

26 minutes ago, Alan Ambrose said:

I'm wondering whether modulating the speed down, if that's possible, will make it quieter?

That would be in 'violation' of the MI's?

 

Deal with the noise pragmatically, and don't compromise the functionality of the STP!!!

 

If folk are reading this, ahead of an intended install, then they will be forewarned / forearmed sufficiently to avoid the issue with more robust methodology.

[Roger440]

7 hours ago, saveasteading said:

It's poor if they haven't designed the pump to be quiet. It is probably cobbled in to the already designed tank as an afterthought, with plastic and screws.

I agree with the earth and concrete slab principle if that works.

Im not sure any of them are "quiet".

 

The vortex i had was hopeless in that regard.

 

Much work was carried out to make it quiet. Whilst 90% better, i was never happy with it. If id stayed, i would have moved it some distance away into a summerhouse we had there. Would have needed a bigger compressor due to distance though.

[saveasteading]

5 minutes ago, Roger440 said:

Im not sure any of them are "quiet".

Can't hear the Marsh Ensign pump. Well I can't anyway.

[Roger440]

As Nick said, mass is what you need. No tine, just concrete.

 

Then line the inside with that egg crate noise absoroption foam.

 

And most important rubber mounts. If i was doing it again, it would be double insulated, ie compressor rubber mounted to a frame using proper rubber mounts, like a car gearbox mount or similar,  wood frame  if you can, which is in turn, rubber mounted to the concrete slab base.

 

Keep an eye on the air delivery hose, this was resting on the base of the plastic duct, which then transmitted resonance to the tank.

 

Sadly it appears beyond the wit of man to design a "silent" sewage treatment plant. Once again, the building industry is miles behind. I guess if you live in a releatively noisy environment it bearable, but when its really quiet on a nice evening all you can here is the bloody pump running!

[Roger440]

Just now, saveasteading said:

Can't hear the Marsh Ensign pump. Well I can't anyway.

Well thats good news, but as above, really depends on background noise. Mind you, the average ASHP will drown it out.

[SteamyTea]

Is there any way, without violating the warrantee, to baffle the intake.

Induction can be one of the noisiest parts of a pump.

[saveasteading]

1 hour ago, Roger440 said:

really depends on background noise

If I can't hear it above the breeze in the trees, or the birds singing, then that isn't sound let alone noise.

 

38 minutes ago, SteamyTea said:

to baffle the intake.

Do we have any sketch or description?

It's just a small box with air hoses in and out, and a cable, isn't it? So maybe just a lump of foam between it and an adjacent surface?

[SteamyTea]

2 hours ago, saveasteading said:

maybe just a lump of foam between it and an adjacent surface

Bit more sophisticated than that.

While this is for variable speed and multi cylinder ICE induction systems, the theory is the same.

 

https://www.researchgate.net/publication/326440306_A_STUDY_ON_THE_DESIGNS_OF_THE_RESONATOR_FOR_REDUCING_RESONANCE_NOISE_OF_INTAKE_SYSTEM_IN_VEHICLE