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View Full Version : Has anyone plumbed there compressor intake outside?



jkilroy
10-10-2008, 12:27 PM
I have heard that plumbing your compressor's air intake outside greatly reduces the sound levels. Has anyone done this and was it worth the effort? Putting the compressor outside, in my locale at least, is just asking for it to be converted to scrap metal. My compressor has two intakes that look like 1 1/4 NPT thread. I have been thinking of building a manifold out of black pipe and extending it outdoors with a large ID piece of hose. Outside I would mount a auto style air filter housing.

davidh
10-10-2008, 12:37 PM
you will notice a difference.

Jim Caudill
10-10-2008, 01:04 PM
I did it. It's been discussed before on the forum, see what Forrest had to say about it. Use at least 1 size larger pipe; Basically I relocated the air filter: I plumbed initally with black iron, then transitioned to PVC, and then reinstalled the air filter assembly. I simply ran mine to the upstairs attic. You could go all the way outside, but I was concerned about drawing moisture in.

tiptop
10-10-2008, 05:31 PM
Jim, I did it about 18 years ago and like it. Yes, the noise level went down. The inlet on my compressor head is oval, so i figurered out the square inches, doubled that, built a manifold adapter and plumbed with PVC. My compressor is located in a loft, so I ran the PVC down the inside wall and then outside. The stock air filter on my compressor was pretty cheesy, so adapted a housing and filter can from a JD tractor I had and ran that. It has about 50 times the surface area and since my compressor still works fine (knock on wood) I believe this was a good choice. Jay

CCWKen
10-10-2008, 05:48 PM
WHAAAAAAAAAAAAAT? I CAN'T HEAR YOU, MY COMPRESSOR IS RUNNING.

Simply adding a better air filter reduced the intake sound level on my painting compressor. It's a reed-valve type and they're always noisy. It doesn't make much difference on the Sullair though. The twin screws are quiet any way. Major sucking noise though. :cool:

For a while, I had a compressor setup outside and built a closet around it. That certainly reduced the sound level in the shop. The closet kept the compressor out of the weather. I mounted a box fan on one side and a louvered panel on the opposing side. The louvered panel was from an old house a/c condenser unit. That worked great for about 3 years. After that, I built a new shop and had more room and power. I'm now thinking of going back to the outside setup. :rolleyes:

Frank Ford
10-10-2008, 08:07 PM
Quite a while ago I received a 12 foot length of 1-1/2" reinforced hose by mistake along with some other stuff I'd ordered, and when I told the supplier, they said, "Just keep it." Later I used it for a quick and easy noise reducer on my 5hp Quincy:

http://www.frets.com/HomeShopTech/Shop/AirCompMuffler/aircompmuffler03.jpg

I just took off the stock air filter, connected the hose to the compressor and hung it loosely from the ceiling. Got a noticeable decrease in the noise level.

PS4steam
10-10-2008, 11:46 PM
Not sure what kind of use you have. I just set up a new 7.5 Quincy for my home shop - ie not high usage. I asked Quincy about the outside intake. There concern was mosture since I did not have any kind of refrigeration or dryer system. They strongly recommended I live with the sound - which is not as bad as I thought it would be. They also suggested I go with an inside muffler before attempting an outside setup.

Bob

A.K. Boomer
10-10-2008, 11:56 PM
might not be a bad efficiency move esp. in the cooler months, drawing in cold dense air is a big plus when compressing, perhaps longer comprendo life too,,, beats sucking it off a hot head...

GKman
10-11-2008, 10:03 AM
I asked Quincy about the outside intake. There concern was mosture since I did not have any kind of refrigeration or dryer system. They strongly recommended I live with the sound

Bob

Unless you are manufacturing air in your shop where do they think it comes from?

Paul Alciatore
10-11-2008, 01:39 PM
Kinda did the opposite. Had a large compressor at one TV station where I worked to supply compressed air for air bearings in the video tape recorders. It was mounted in an equipment room that was indoors but not air conditioned. Moisture was a constant problem and even one drop in an air bearing would produce instant downtime.

Ran the intake through the nearby wall into an air conditioned space to pick up dryer air. I believe we used a reducing coupling to go up one pipe size at the compressor intake to insure there was no problem with flow. Had a filter on the intake end which aided in reducing noise, but we weren't really concerned as it was just a storage space.

But this was not the only moisture control measure. The exhaust from the compressor tank went to a 50 foot copper coil that was also mounted in the air conditioned space. Air flowed in an upward direction and moisture condensed and drained back toward the compressor end to a collection jar. Then more filter jars, a refrigeration dryer and some final filter jars. Finally the run to the point of usage was a long, upward slope with an additional (older) drip loop in the middle. One last filter jar at the tape recorders, just to be sure (it had to come downhill there so any moisture in the last part of the line would find it's way there). We never had even a single drop of water past the dryer. All filter jars were redundant with valves for maintenance while running.

Ran fine for years in south Florida climate. Probably still going.

NickH
10-12-2008, 05:04 PM
Yes,
I added a filter that was too big & heavy for mounting on the compressor so I stuck it on a length of plastic pipe, big noise reduction.
Then I did a 2-pack paint job, started getting a bit spacey halfway through & realised my airfed mask was getting inside air, threw the filter out after that :D
Nick.

brian Rupnow
10-12-2008, 07:17 PM
I did it in my last garage before where I live now. It does indeed make the air compressor quieter, and I never seen any bad effects from having the air inlet tube poked out through the wall. You do need a large air filter to keep the mud wasps from trying to build a nest in the air intake, and the tube from the compressor head out thru the wall should be as large as you can use from your cast air inlet manifold out through the wall, and kept as short as possible. If you plan on spray painting, there would be problems with air temperature in the winter time, but thats the only issue that I can think of.

jkilroy
10-13-2008, 06:52 PM
Thanks for all of the input. Moisture is not worth worrying about, my shop is 3 blocks from the Mississippi river, located in central Mississippi. The humidity is almost always high, inside or out. I have central air but try not to run it, really kills my wallet come electric bill time, I have a HUGE box fan instead. I do run a dehumidifier 24/7 and man that thing pulls out the water. I'm going to try the piece of hose intake silencer trick from Frank Fords post as an initial shot.

Lee in Texas
11-23-2008, 11:31 PM
Thanks for all of the input. Moisture is not worth worrying about, my shop is 3 blocks from the Mississippi river, located in central Mississippi. The humidity is almost always high, inside or out. I have central air but try not to run it, really kills my wallet come electric bill time, I have a HUGE box fan instead. I do run a dehumidifier 24/7 and man that thing pulls out the water. I'm going to try the piece of hose intake silencer trick from Frank Fords post as an initial shot.

FWIW- If you want a hose and filter exactly like he has, it's an intake for a "trash pump". I'm a plumber and I've used those for pulling water out of a trench. Check with home improvement stores. I believe I saw one at Lowes.

Evan
11-24-2008, 07:39 AM
Build a box from 3/4" MDF in the shape of a cube and provide a fitting with appropriate hose to the box and compressor at least a few feet long.

Cut a hole in the center of one of the faces of the box perpendicular to the face with the intake with a hole saw. Use a piece of PVC or ABS plastic pipe and make a port the same as a ported speaker. Experiment with the length of the port tube until most of the fundamental frequency of the sound pulses cancels out.

If you want to go step further and achieve nearly total silence from the intake install a cheap condenser mic in the hose near the compressor intake. Install a small midrange speaker with a poly cone in the face opposite the intake port with the speaker pointing into the box. Hook up a small amplifier with a few watts of output power and connect the mic to the input. Hook the speaker to the output and play with the speaker phasing and volume until the sound is at a minimum. You should be able to cancel just about all of the sound to the point it is inaudible.

This sort of situation is ideal for using active sound cancellation. Active cancellation is being used on industrial machinery and can cancel the sound of a large diesel engine by using the same trick on the exhaust as well as the intake to the point where the only noise it that radiated from the engine block.

noah katz
11-24-2008, 01:42 PM
Get an air filter and airbox from a car; they're designed to reduce noise and will certainly flow enough air.