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air compressor box

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Project by Mainiac Matt posted 03-08-2012 12:54 AM 5671 views 29 times favorited 25 comments Add to Favorites Watch
air compressor box
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Anyone who has a larger capacity oiless type air compressor knows that these pigs are LOUD!!!

When I started occupying my newly finished basement shop, I wanted to have air, but knew I’d catch heck from my wife in the family room above, if I ran my aging Devilbus airless.

So I designed and built this noise dampening box.

3/4” plywood, lined with 1/2” sheetrock (to increase mass and give it some fire protection)

The compressor sits on a “floating deck” which is supported by polyethylene foam blocks. The key here is not to use so much foam that you never compresss the foam (like driving a 1-ton with an empty bed) , but not so little that it “smushes” (like driving a S10 with a pallet of bricks in the bed).

The sheet rock is covered with a fire retardant polyurethane egg crate foam.

The compressor does not contact the foam on the walls or ceiling.

Air connections are all made with rubber hose, so no sound transmits out hard piping.

I wired a switched recepticle inside the box, so the compressor is turned on via. the 20 amp switch on the wall above.

And I pulled the drain petcock and ran a hose to a ball valve on the outside for easy blow downs.

I keep the compressors regulater wide open, and mounted a salvaged industrial one on the exterior side for easy pressure adjustments.

There are air make up holes on the back side, below the floating deck.

1” birch plywood on the top makes for a sturdy work surface.

The door is gasketed and mounted with hinges and spring loaded twist latches.

All the air line are made up with quick disconnects, so I can open the door, pop the air lines, unplug the cord and wheel her out to the barn or a job site if needed…... though I broke down and bought a 100’ hose for when I need air in the barn.

Now the kiddies and mamma can watch t.v. in the room directly above and I never get a complaint whent he compressor cycles.

Finished it up back in the fall…. and it took way to long to complete. But now I have good air capacity without rattling the house down… and didn’t have to buy a new compressor.

Got the idea from this book…. Setting Up Shop

-- Pine is fine, but Oak's no joke!





25 comments so far

View KnotCurser's profile

KnotCurser

1843 posts in 1754 days


#1 posted 03-08-2012 01:03 AM

Great design, but wouldn’t the motor overheat with no air flow around it?

-bob

-- Robert Rhoades WoodWorks / Email: rrww@rhoadesclan.com / www.rhoadesclan.com

View Woodwrecker's profile

Woodwrecker

3632 posts in 2261 days


#2 posted 03-08-2012 01:05 AM

Man, this compressor box was right on time.
My one neighbor lady, (who always waves at me with one finger) was complaining about my oiless compressor when it cycles out in the shop when I have the door open.
(OK, so it loud, but I’m half deaf. It don’t bother me..lol)
Mine is an upright model but I am going to use a few of your nice design features to quiet that bad boy down a little.
Then I’ll wait for her to complain about something else .
Thanks for sharing your smarts.

-- All glory comes from daring to begin.

View Dusty56's profile

Dusty56

11663 posts in 2374 days


#3 posted 03-08-2012 01:13 AM

Interested in knowing what you did for intake air and ventilation / heat removal ?

-- I'm absolutely positive that I couldn't be more uncertain!

View markplusone's profile

markplusone

62 posts in 1641 days


#4 posted 03-08-2012 01:26 AM

Yeah you have to get some air circulation in there. The reason thes oiless compressors get the CFMs they do is from hi rpms. High rpms = high heat. Thats why there is that plastic shroud around the motor but more specifically the piston and its fins. You need to get some way of getting fresh cool air in to that cylinder head because otherwise youll fry the piston ring (which is a rubberized plastic) right out of it and your looking at a new piston and sleeve kit. Now this info I have is not just my own. It actually comes from the cambel hausfeld tech I talked to when I was having problems with pressure build on mine. Now the easiest way I can think to do this would to build a small tunnel 4”x4” maybe, lined with your foam stuff and having 2 90deg. turns and entering your box somewhere close to the bottom. Then another connected to the box at the top. Then I would run the compressor and see how much air is moving through the box. If not satisfied, I would mount a small fan at the entrance of the lower tunnel. Thats just my initial brain fart. Anyways, the whole thing is that to prolong the life of your pump, you need cool fresh air moving through that fan/motor shroud.

-- Dont carry that which you dont hold with.

View pitchnsplinters's profile

pitchnsplinters

262 posts in 2124 days


#5 posted 03-08-2012 01:43 AM

Looks hot in that box.

-- Just 'cause a cat has kittens in the oven, it don't make 'em biscuits.

View lizardhead's profile

lizardhead

518 posts in 1527 days


#6 posted 03-08-2012 01:44 AM

What he is not telling us is that the compartment was so air tight that when the compressor ran it sucked in the cabinet.

-- Lizardhead---Yeah but it's a dry heat--Tempe, Az

View Martyroc's profile

Martyroc

2708 posts in 992 days


#7 posted 03-08-2012 01:50 AM

That’s a great idea, please repost when you get the air circulation gets hammered out. I want to do the same thing. With the DC, TS and AC going I can’t hear anything in my shop, and since it’s my garage on the common wall is my dining room it gets pretty loud in the house.

-- Martin ....always count the number of fingers you have before, and after using the saw.

View Mainiac Matt 's profile

Mainiac Matt

4136 posts in 1014 days


#8 posted 03-08-2012 02:01 AM

As far as air supply to be compressor…. there are holes in the back wall low, below the floating deck. This allows air to come in and flow around the deck to the main volume.

As far as air flow for cooling goes, that is a definate concern.

Mitigating factors are:
>I live in the north.
>I don’t leave the system on when I’m not using it. So it’s not cycling all day.
>This is a hobby thing for me, so at best, I fire it up a couple nights a week…. it comes up to pressure quickly, I fire some brads, blow some air and shut it off. The die grinder has been the biggest air hog that I use, and even then, with a 20 gal tank, it may cycle two or three times b4 I’m done.
>It’s in the basement, so ambient temp is pretty cool…

I’ve opened up the door and checked the temps after some extended work sessions and though it’s been warm, it’s never been what I would call hot.

None the less, you have pegged the weekness of the design and I need to keep an eye on it. If it looks like it’s going to become a problem, I’ll have to hook up a fan and put some vent holes in. Right now I’m not willing to give up a decrease in the noise reduction.

Then again, if I fry the compessor… I’ve got a legitimate “need” and can lobby my wife for a new twin cylinder, crank case type model. Or maybe I could retrofit a crank case type pump on this platform.

-- Pine is fine, but Oak's no joke!

View Rickert's profile

Rickert

11 posts in 979 days


#9 posted 03-08-2012 03:06 AM

Nice design ssnvet. As far as cooling the compressor, is there any way to make a false ceiling, similar to the false floor, letting hot air to escape?

—another Mechanical Engine Ear

-- Christianity, if false, is of no importance, and if true, is of infinite importance. The only thing it cannot be is moderately important. -- C.S. Lewis

View Mainiac Matt 's profile

Mainiac Matt

4136 posts in 1014 days


#10 posted 03-08-2012 03:09 AM

“False ceiling”

That’s a good idea…

-- Pine is fine, but Oak's no joke!

View MrMeasureTwice's profile

MrMeasureTwice

115 posts in 1107 days


#11 posted 03-08-2012 04:57 AM

ssnvet – sweet design, simple, yet effective.

Thank you for your service – I have the utmost respect for bubbleheads. After taking a 5 day cruise on the USS Permit I got a really good idea of what submarine service is like. It was pretty cool sleeping on a torpedo for 5 nights though… :-) Now THAT was hot-racking!!!
(I am ex-Navy, 1984-1992, P-3C Orion In-Flight tech – we used to hunt subs)

-- -- Jim “Mr. Measure Twice” Marchetti -- http://www.mrmeasuretwice.com/

View jmanleisure's profile

jmanleisure

18 posts in 1294 days


#12 posted 03-08-2012 03:07 PM

Great design and idea… perhaps all you need to cool the air is some type of cheaply made heat exchanger-like cold water flowing through copper tubing around the existing vent holes. Then again, if its not hot and it works, no need to mess with a good design.

View rodneyh's profile

rodneyh

127 posts in 1350 days


#13 posted 03-08-2012 04:45 PM

I haven’t worked on anything like this, but I have worked on a lot of heat transfer problems. You should be able to get around the box heating up problem by adding a small fan inside the box aimed at the cooling fins. Here’s the equation: Q = hADT where Q is the heat transfer out of the fins (what the compressor really cares about), h is the heat transfer coefficient, A is the fin area and DT is the temperature difference between the fins and the air in the box. By putting in a small fan you increase h by a factor of about 10 (compared to what it is with no air movement). This then allows DT to be 10 times larger and still have the same cooling. Now I have no idea how hot the fins are normally, but it must get pretty hot if they’re shrouding it. If you conservatively estimate it to be 120F and a 70F normal environment, that’s a DT of 50F. 10X that is 500F and you’re still extracting the same heat from the fins. Your box isn’t going to get anywhere near that hot even with only your small air “breather” holes. If it does, you’ve got way bigger problems (involving melting and flames and such). I’m sure there are other parts of the compressor that can’t handle extreme box temps, but the compressor head itself should be fine. I’d also point a fan at the motor for the same reasons. Note that you will only get this increased cooling on components that are actually generating heat. A switch or similar component would still be at the same increased box temp and may not be rated for that.

View Mainiac Matt 's profile

Mainiac Matt

4136 posts in 1014 days


#14 posted 03-08-2012 08:03 PM

we used to hunt subs

Now be honest shipmate…. you used to “try” to hunt the subs :^)

But we always appreciated you guys flying donuts in the air to make our comms more ‘resilient’.

Q = hADT

Are you tryin’ to give me flashbacks and bad dreams Rodney? :^O That’s a great right up though…. and illustrates well that temp difference is only one factor.

These oiless style compresors have the motor direct driving the air pump, with a plastic fan mounted on the motor shaft on the opposite side. The plastic housing serves to duct the air accross the air pump fins and then the motor itself….. (as well as keeping your pinkies out of the moving parts).

I only know this because two summers ago, I built a 30’ x 20’ pole barn and ran the compressor pretty hard running two nail guns and a impact driver (to drive big lag bolts) and that little squirrel cage fan came off and broke. I had hired help on site so I couldn’t shut down and wait days for the part…. so I ran her for a few days with the cover off and no fan, untill I got the part.

Since the box is up against an exterior wall, and I still have part of the ceiling left open and can see the sill. I think I’ll plumb some 3” PVC up through the sill like a snorkle and maybe put a PC cooling fan or two in the line to move some air. I could wrap the pipe with insulation to help dampen any vibs and keep the noise down.

One more project to the list :^(

With my luck, the tank will probably rust through a week after I have it all wrapped up.

-- Pine is fine, but Oak's no joke!

View Dennisgrosen's profile

Dennisgrosen

10850 posts in 1801 days


#15 posted 03-08-2012 08:20 PM

good idea
making a box like this … you have to think loudspeaker …. sort of when it comes to the two 90 turns
and the air intake
though you have to make a few more corners .. sort of by placing two halfwalls
in the tunnel one on each side to make a trap for the noise but not restrict the airflow
and then isulate the hole tunnel

Lizardhead :
you have to make a second wall that is both isulated and flooding ,free from the ceilling , the floor and walls
the best wuold bee if you cuold diconnected the shop and the house with a rubber sealing around
on the ceilling,walls and floor .... so no sound can be transfered thrugh the wall , ceilling and floor

thanks for sharing

Dennis

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