Noise Insulation for shop compressor?

[MossRoad]

Not sure about compressor longevity, but for a fixed displacement compressor such as a piston compressor, it is most efficient when it is turned on and off.
If you have a check valve and a bleed down valve (so that the compressor starts unloaded), your motor should not have much startup load.


Aaron Z

Yeah, I do have all that. And I understand pretty well how it works. I was just thinking out loud, that if you run a compressor with no load will the supply air moving through it do any noticeable cooling to the compressor, or will the air friction and piston movement, etc.... generate more heat than the cool supply air could offset. The electric motor running under load also gets hot, running under lesser load would move some cool air through it.

Efficiency wise, it's a loss I guess. I think I read something about it taking 8 electric HP to create 1 compressed air HP.

 

[MossRoad]

I also read some comments/questions about running an air compressor outside in cold weather. Found several articles explaining it's more efficient to compress cold air VS hot air. The main concern was the moisture content of the air being compressed.

So lets say you're in your garage with the door open, it wouldn't matter, because the outside and inside air is about the same moisture and temp. If you have a heated shop with the doors closed, it would probably be less humid inside VS outside. Just a bunch of things to think about. Does it really make a difference to a light user like myself? I doubt it. But it may for someone that does shop work, small business, big hobby, etc...

 

[not2old]

I'm thinking Super Cold air would really multiply the amount of condensation in the tank. Think I'd rather try to lower the noise by other means first.

40 years ago I serviced compressors for while. The cold air intake will actually reduce the amount of water in the tank. We actually recommended an outside air intake for well used compressors in auto body shops. This was in Vancouver, B.C. where it rains all winter. The worst I saw was from a complaint about the compressor running constantly, without stop when using air. I drained over 60 gallons of water out of the 80 gallon tank and changed the oil. When testing performance afterwards it produced pressure and volume as new. It had never had an oil change or been drained of water in over 10 years.

 

[BukitCase]

Mark, if you don't wanna wait when sand blasting I think you're gonna need to "move up the food chain" a bit - my compressor is a DevAir TAPV-5052, REAL 5 horse Baldor 1725 rpm motor, 80 gallon vertical - pressure lubed pump, just under 20CFM @ 150 psi - pulls 22 amps/240 volts when running. Weighs right at 700#.

TAP Reciprocating Compressor | DV Systems

I STILL hafta wait for it a little bit if I blast continuous for more than a few minutes.

It cost me $1800 11 years ago, current price is a bit higher -

TAPV-552-3 5 HP COMPRESSOR 23/6/1 /6

Pump runs at around 700 rpm, I just checked sound level yesterday and at 6' away it's 85 dB A weighted, slow response (not a cell phone app, I've done video and audio production so have a REAL SLM) - that isn't so loud you can't carry on a conversation, but it's close...

I also used the spectrum analyzer app (mentioned previously) at the time, predominant frequencies run from a bit above 100 hZ up to 1500 hZ. The compressor is currently STILL bolted to its shipping pallet just inside my garage and I've done ZERO mods to it so far ( Other than adding an auto drain, 15 seconds once every 2 hours) much of my use of air is in the other shop, 100 feet away thru 3/4" lines, it's pretty quiet from there :laughing:

I haven't measured the SPL in the house, but it's almost inaudible - surprising, 'cause my crappy house very likely has ZERO insulation in the wall between house and garage :thumbdown:

When the garage eventually gets turned into more living space, the compressor will need a new home; at that time it may get it's own "dog house", as we ALL know there's no such thing as "un-used shop space"

Betcha you STILL haven't followed the John Sayers link I posted earlier :laughing: ... Steve

 

[Industrial Toys]

Since the water in the compressed air turns to steam, then condenses back to water, I guess a source of air that has the least amount of water in it to start with would be best. My compressor is in a heated unoccupied storage room. I have had very little condensation issues. But the air has to ultimately come from somewhere. It doesn't suck all the air out of my room.

 

[cqaigy2]

I'm thinking Super Cold air would really multiply the amount of condensation in the tank. Think I'd rather try to lower the noise by other means first.

Super cold air has very little moisture in it.

 

[ray66v]

You want as clean and dry intake air as you can get. So, cold outside air would be good.

However, starting an electric motor and a pump in freezing conditions is not so good for it. Our shop ended up with an external building, basically a shed, that housed the compressors. We had to heat that shed in the winter. It was not pleasant to hear they way they sounded if you didn't.

My compressor at home has a setting where the motor and the pump can run continuously. In this mode, the valves are held open on the pump and it does not compress air, unless the pressure switch calls for it. This is to allow the pump to run cooler when operating under heavy loads. I also usually run a box fan on it when the ambient temperatures are high.

 

[dragoneggs]

Okay a bit deeper dive into my Husky 3.7hp 60gal compressor...

Pulleys
Motor = 4in
Compressor 12in
Centers 10in

Motor = 3450rpm
Compressor = 1150rpm



Compressor is mounted on double sheet of 3/4in plywood and HF 3in polyurethane casters.

Noise (pretty much against wall)

88dB @3ft
85dB @6ft

Noise (compressor 3ft from wall and rotated 90deg so front/back not facing wall)

86dB @3ft
83dB @6ft

Compressor intake on top with filter on side. 2 intake ports about 1.25in by .5in (a little smaller but couldn't fit my calipers)

 

[BukitCase]

I had a Campbell-Hausfield 2 horse compressor with a similar intake; never did get around to modding it for a real filter - it's doable, but would probably be a quicker (and more effective) project to build a doghouse outside ... Steve

 

[Doofy]

Okay a bit deeper dive into my Husky 3.7hp 60gal compressor...

Pulleys
Motor = 4in
Compressor 12in
Centers 10in

Motor = 3450rpm
Compressor = 1150rpm

View attachment 667348

Compressor is mounted on double sheet of 3/4in plywood and HF 3in polyurethane casters.

Noise (pretty much against wall)

88dB @3ft
85dB @6ft

Noise (compressor 3ft from wall and rotated 90deg so front/back not facing wall)

86dB @3ft
83dB @6ft

Compressor intake on top with filter on side. 2 intake ports about 1.25in by .5in (a little smaller but couldn't fit my calipers)

View attachment 667351 View attachment 667352

Informative write-up. My silencers should be here later this week so I will be experimenting to get the decibel numbers down. I am glad my intake is tapped for pipe behind that ridiculous plastic box. At least yours has something that actually resembles an air filter.

 

[dragoneggs]

Informative write-up. My silencers should be here later this week so I will be experimenting to get the decibel numbers down. I am glad my intake is tapped for pipe behind that ridiculous plastic box. At least yours has something that actually resembles an air filter.

Yeah adding a muffler on mine looks to be a challenge. If anyone has any bright ideas I'm all ears.

 

[downsizingnow48]

Hard to know if it is worthwhile, maybe the existing setup is attenuating the sound pretty well. You could test the db with and without.

But it could be done simply I think. Make a replacement top plate of 1/4" aluminum, drilled to take one or two of the standard air cleaner/mufflers. Screw on with existing screws. Then block off the existing opening with whatever is handy and set in with some adhesive. Might be worth an hour or two to do that.

 

[Doofy]

Yeah adding a muffler on mine looks to be a challenge. If anyone has any bright ideas I'm all ears.

It does look challenging. It appears like the reed valves are right there with no pipe fittings to use. Interesting. I will know if the silencers are worth messing with later in the week.

 

[ruffdog]

Polar Air runs a bigger pump at a slower speed and has a huge silencer box that the intake lines are plumbed to.

Polar Air by Eaton Compressor Whisper 1 Silent air Compressor - YouTube

 

[dragoneggs]

Or I could just settle on this...

Amazon.com: California Air Tools 6DCADC Ultra Quiet, Ultra Dry Oil-Free 4. Hp: Home Improvement

Is 75dB worth it?

 

[ruffdog]

Is 75dB worth it?

When you drop from 90dB to 75dB, the noise level drops 5x............that is a huge difference.

 

[pmsmechanic]

When you drop from 90dB to 75dB, the noise level drops 5x............that is a huge difference.

I agree that's a huge difference, but at $3,520.09..... The question was "Is it worth it?" I say no.

 

[dragoneggs]

When you drop from 90dB to 75dB, the noise level drops 5x............that is a huge difference.

I get the log scale for dB and that is a huge drop, but honestly I don't have a clue what 5x means in terms of audible sound. Need to hear it side by side.

I agree that's a huge difference, but at $3,520.09..... The question was "Is it worth it?" I say no.

Worth it... nope. Got other tools I 'need' first. Time to get on with the design of the outhouse for the compressor. Doghouse is covered... that is my shop. Recently plumbed for a sink and small fridge, just need a foldable cot. :laughing:

 

[Doofy]

75dB is about as loud as a toilet flushing or a vacuum cleaner. That level will not damage your hearing. Usually, anything above 85 dB could possibly cause problems with extended exposure. I will get my compressor down to 75-80dB for hopefully less than $30.

 

[ruffdog]

Would this one for $1400 shipped be ok?

California Air Tools CAT-60040CAD 60040CAD Ultra Quiet & Oil-Free 4-HP 60-Gallon Steel Tank Air Compressor w/ Auto Drain