Great air, but bad squeal

[Chuck E Cobb]

Hi folks, I have a question and thought perhaps someone here may just know the answer. We just installed a new massive compressor at the wood shop I work at. The owner had 1" galv. pipe installed to 4 work stations each has a quick connect and it all is fine, except for the fact that at the compressor when ever someone uses air there is a loud squeal. Now I think the sound is coming from either the dryer or the regulator that is next to the compressor.

So the question is has anyone ever had this problem? and if you did, what did you do to fix it?

Thanks
Chuck

[Steve Clardy]

Strange.

Regulator diaphram possibly? Not sure

Is the compressor running when it does this?

[Chuck E Cobb]

No it's not running when it happens and I was also thinking it was the diaphram too, but ow to get it to stop? it is driving my crew nuts :) not that most of them are not already half way there anyway.

Chuck

[Lee Schierer]

Regulators need to be properly sized for the flow rate through them. It sounds, no pun intended, like yours may be improperly sized for the rate of air flow being run through it. I found this on the internet that may be of some help to you:

"Noise generated in a regulator is a function of flow rate, pressure drop, and pressure-drop ratio (the pressure drop divided by the absolute inlet pressure).

Most regulator manufacturers provide information showing variations in noise levels at a standard distance (e.g., 48-in. downstream, and 30-in. from the pipe) with different pressure-drop ratios, inlet pressures, and flow rates.

Flow rates through regulators smaller than 2-in., and with inlet pressures of less than 300 psig are unlikely to produce hazardous noise levels, as defined by Occupational Safety and Health Administration standards. That's not to say people won't complain about noise; volume should be carefully considered.

Noise does not generally come directly from the regulator, but from downstream piping. Using heavier walled pipe and/or insulation downstream of the regulator reduces noise, but also causes the noise to radiate further down piping beyond the heavier pipe and/or the insulation.

Coping with regulator noise can be handled in several ways; the best solution may combine approaches.

Common approaches to reducing regulator noise follow.

1. Locating the regulator farther from occupied spaces is often not feasible, but should not be overlooked as a viable solution.
2. Changing the pipe design to reduce flow rate or pressure-drop ratio at the regulator may require using diffusers, or multiple regulators installed in series or parallel.
3. Using heavier schedule pipe will reduce noise levels, however changing a 4-in. steel pipe from Schedule 40 to Schedule 80 reduces the noise only about 5 dB. (For reference, reducing noise by 6 dB is approximately equal to reducing sound pressure by half.)
4. Using 1-in. of thermal insulation reduces noise about 3 to 6 dB, up to a maximum of about 12 to 15 dB. Acoustical insulation is more effective and can reduce noise by 8 to 12 dB for each inch of insulation up to a practical maximum of about 24 to 28 dB.
5. Silencers, using similar principles as an automobile muffler, can provide 24 to 28 dB of noise reduction when installed immediately downstream of the regulator.
6. Regulators come in a variety of designs, some designs produce more noise. Selecting a regulator with a "quieter" design may cost more to purchase, but less to own after considering installation and maintenance costs. "