Bolt Down Air Compressor Or Not & Antivibration Material ?

[dave*99]

I find nerd material quite interesting even when it’s over my head. LOL

My first assumption of noise production would be the piston. Assuming most of us have piston compressors. To get the frequency of the noise (piston cycles), take the motor speed, figure out the pulley ratio, do the math to get the compressor speed. Since the piston goes up and down in one revolution, divide the compressor speed by 2. Get the units in “events” per second. This is how many times the piston is going up or down essentially. This is the frequency.

Then, you put the frequency in this formula as the WH and solve for V0 which is the volume. Build your muffler with this volume. I suspect this may be the volume of the silencer boxes on the compressors. Something like this is how they ‘engineer’ the solution instead of completely guessing.

What Is Helmholtz Resonance and How Does It Work?

Explore Helmholtz Resonance: the core principle governing how air volume and openings control sound frequency.

engineerfix.com

Helmholtz resonance - Wikipedia

en.wikipedia.org

An audio spectrum analyzer app on your phone will make short work of identifying the frequencies of the sound.

 

[sparky 1971]

I have two 2'X2'X3/4" pieces of treated plywood screwed and glued together with the compressor mounted to those but rely on gravity to hold everything to the floor. So far it works well but I don't know how much the plywood reduces the noise if at all.

 

[ericm]

Not related to bolting it down but I just bought this compressor, and man is it quiet!
https://www.northerntool.com/produc...-90-psi-150-max-psi-230v-single-phase-5899641

Cool! Looks like they licensed Eaton's patent. https://patents.google.com/patent/US10578089B2/en?oq=10578089

 

[finn]

I have an 80 gallon, 2-stage Champion.
I bought a box of rubber floor tiles from Menards, used four of them and gave the rest away.
Not bolted down and it hasn't budged an inch.
For noise mitigation, it is in a tool / storage room closed off from the rest of the shed.

I have essentially the same compressor, but mine dates to 1970.

I put hockey pucks at the bottom of the legs. It’s not bolted down, and has moved maybe two inches since I got it maybe ten or twelve years ago. The only reason it moved is because the flexible hose connecting it to the regulator and black iron air distribution pipe was a little too long. After the initial run in it’s new home, it hasn’t budged..

I also have an old (1975) Rand 80 gallon compressor in the other garage that’s probably been there twenty five years. Same hockey puck and hose setup and it hasn’t moved either.

The champion is in the boiler / electrical room with no door. Noise from the compressor doesn’t bother me, but I normally work at the other end of the shop, 75’ away. I wear hearing protection when using most air tools, though.

The Rand is in its own room / closet with a door. It’s pretty loud even with the door shut. The door has an inch and a half gap at the floor for ventilation / makeup air, but if using the compressor for longer periods I have to leave the door open to control the room temperature.

 

[427HISS]

I have essentially the same compressor, but mine dates to 1970.

I put hockey pucks at the bottom of the legs. It’s not bolted down, and has moved maybe two inches since I got it maybe ten or twelve years ago. The only reason it moved is because the flexible hose connecting it to the regulator and black iron air distribution pipe was a little too long. After the initial run in it’s new home, it hasn’t budged..

I also have an old (1975) Rand 80 gallon compressor in the other garage that’s probably been there twenty five years. Same hockey puck and hose setup and it hasn’t moved either.

The champion is in the boiler / electrical room with no door. Noise from the compressor doesn’t bother me, but I normally work at the other end of the shop, 75’ away. I wear hearing protection when using most air tools, though.

The Rand is in its own room / closet with a door. It’s pretty loud even with the door shut. The door has an inch and a half gap at the floor for ventilation / makeup air, but if using the compressor for longer periods I have to leave the door open to control the room temperature.

I wish I could house my compressor in a outdoor shed, that would be fantastic. If I were younger, I would.