compressor sound proofing

[pondy]

hope this is the right section, I will be starting this project in the new year but after some advice before I get started.

I have a little 50l, twin piston direct drive compressor, its in my garage which is in a block for the people in our close, my garage backs onto someone elses garden, I have only been here for 7 months and don't want to annoy my neighbours, its also to loud I usually get out the garage when its on, I downloaded a decibel app on my phone and measured it at 86db.

compressor


airline etc




the compressor sits under my work bench, I plan to build a wooden frame around the compressor then board it off with mdf or ply wood and have a door at the front so I can get the compressor and turn it on and off and drain water etc. all the joins would be sealed up with silicone sealant and a small rubber seal around the inside of the door so I closes tight with no gaps?

I want to line the inside with some sort of sound proofing but unsure whats best? I have never delt with anything like this before so just searched sound proofing on ebay and it brings up products like this

http://www.ebay.co.uk/itm/Acoustic-..._Acoustic_Treatments&var=&hash=item51ab415a0a

can be sprayed with adhesive and stick to all sides, roof and door, does any one have any experience with this product or anything like it?

my biggest thing is going to be ventilation and cooling. I have a few of these in my 'random bits box'



I could place one low down at the back of the box which would such in cool air and one high up on the door which would let warm air vent out from. there is a large van on the back of the compressor which sucks air in and blows in over the pump, problem being I don't want this box to take up to much space and at the moment I run the compressor hard against the wall, this fan is then around 1 inch off the wall, is this a problem? I was thinking of getting a bathroom extractor fan to put into the side of the box with the flexible ducting to direct cool at the back of this fan?

I want to remove the small air filter from the heads, and with the fittings and some hose running outside the box and mounted on the wall so I don't draw in warm air inside the box which will cause more water inside the tank? I need to find out what size the fittings need to be in the head, I know after using a gauge from my tap and die set that the pitch is 1.50, and my calipers show an external diameter of 15mm, it this a normal size?





one last thing for the time being in the hight of the box, the compressor stands 60 cm tall, my work bench that its under stands 95cm tall. I could build the box tight to the top of the compressor and have a little storage area on top or I could build the box right up to the bottom of my work bench is the top, giving me around 35cm of area for hot area to rise to and vent out, any input on that's best? Im thinking more of the second option

 

[ukracer]

hope this is the right section, I will be starting this project in the new year but after some advice before I get started.

I just made a temp box up lined with old carpet and was amazed how quiet it is. Next door said !what compressor! when I asked how the noise was

 

[normspanners]

One of the best ways to quieten it is to rubber mount the pump on the tank, as it acts as a large amplifier (like a bell), try hitting a large empty gas cyl. the pipe from the head to the tank would also need to be flexible to accommodate the movement. Also go to a hydraulic hose repairer and get a male male adapter which matches the head thread ie your filter and fit a screw on oil filter off a car with a similar thread.I have one compressor inside my house in the boiler room and I can only just hear it through the door to the kitchen.
sound deadening material is usually lumpy foam like they use as transport packing for computers or pcb's , another thing you can use is very large 48's? cardboard egg boxes glued on the inside of the box, it is the shape, it breaks up the sound waves and stops it 'slapping' the housing Then to allow air out of the top you could drill holes through the lid and the tips of the lumps on the egg boxes and make sure that the holes dont align / coincide so the sound has to do a zig zag to get out

 

[RBDIVE]

Material you find good at soundproofing would be rockwool bats, they sell them in wickes, also plasterboard is good if it's thick. After all that's what is specified for buildings.
Noise its all about providing resistance/deflection to the travel of noise, hence why carpet and egg boxed work

 

[pondy]

Thanks for the replys. The pump is isolated from the tank with rubber blocks. I have since purchased all my materials for this and will start at the weekend. For sound proofing im using 50mm insulation boards.
I'm worried about sound escaping via the intake and exhaust my of my box, should I make a z shape ducting on the vent?

 

[normspanners]

The rubber blocks, are they totally isolated, as per a car engine mount or exhaust mount, if it is just a bolt through a rubber pad they wont work.
If the vent is a direct line through there is not much point in all the sound deadening as the noise will just pass straight out.
I have taken apicture of proper sound proofing today I will upload it later.

 

[pondy]

they are just rubber pads around 5 mm think between the pump and the tank. so something like the link bellow would be better and change the solid hose between pump and tank with a rubber hydraulic hose etc?

http://www.ebay.co.uk/itm/Anti-Vibr...353?pt=LH_DefaultDomain_3&hash=item2586714db1

I wanted to add a periscope shape bit of ducting on the side of the box on the back of my vents, this would then give two 90 degree corners for the sound the try and get around while still allowing air flow? or put tumble dryer ducting on the back of the vent grilles in the s bend shape?

 

[normspanners]

go to your local exhaust supplier and get some exhaust bobbin mounts thats what I use
On the 'silent' pumps I work on the air vents are lined with sound deadening if you look at the photo I took today you can see the texture of the deadening on inside of the doors. that is the secret of it, the shape breaks up and absorbs the sound wave

 

[pondy]

Thanks for the picture, I have already ordered two large sheets of dense insulator board, but its still a flat surface now I have given it more thought. tHe stuff in your picture is not cheap, this was £25. I will see how it works, im sure rubber mounts, enclosure and sorting the air filters will make a big differance

 

[the snooper]

those decibel apps are not accurate as they cant be calibrated to the microphone on the phone, as for your air vents the trick there is to put as many turns in the outlet / inlet as possible as sound doesn't travel well round corners. its reflected and will make a huge difference, you can also make an exhaust silencer using the same method

 

[normspanners]

many turns in the outlet / inlet as possible as sound doesn't travel well round corners. its reflected and will make a huge difference, you can also make an exhaust silencer using the same method

BUT you have to careful it can increase it !! see quote below.
A labyrinth trap, speakers use the same but for your app putting sound deadening on each of the turns makes a HUGE difference. but a compressor doesnt have an exhaust actually I think you can get a head to receiver pipe silencer similar to turbo silencers.

What Is Labyrinth Slot Venting?

Labyrinth Slot Venting is a form of "porting" on a much higher level verses cutting a hole in a box and dropping in a port tube.

The Labyrinth Design increases the amount of bass your woofer produces without adding any additional power to your system.

As with all porting designs, the Labyrinth opens up the back side of the woofer so more sound can escape from the inside chamber of the box. By utilizing both the "push" and "pull" motion of your sub woofer the design of the enclosure is magnifying the sound of the sub woofer without exterior power added.

However, the porting process can also decrease sound if done improperly. This is done when the enclosure is tuned incorrectly to the ideal requirement of your sub woofer. A simple explanation would be the sound waves traveling from the "pull" of the woofer will cancel out the sound waves firing from the "push" of the woofer. Not only will the sound be adversely effected but continued play will cause permanent damage to the sub woofer.

The design of the Labyrinth Slot Vent brings a controlled sound level increase. By its "MAZE" design, long low frequency sound waves easily escape while short high frequency waves remain trapped unable to cause unwanted cancellation and distortion. In turn, this gives you the listener, loud clean bass a sealed or basic port design can not deliver.

 

[Wallace]

After you have built the box cooling is going to be your next biggest problem. The compressor cooling fan has a very high flow rate and with only air vents in the box it will recirculate the warm air inside raising the ambient temperature within and those direct drive V twins don't like heat. For the compressor to be free-standing and not overheat the box will need a flow of cool air through it greater than the compressor cooling fan flow to take the heat away. Ducting the compressor cooling fan inlet from outside the box so it can only draw cool air in and an exhaust vent in the line of airflow would remove heat by semi pressurising the box but it will still get warm in there particularly as you are using heat insulation for sound deadening.

 

[pondy]

I don't think I put enough thought into this project. This compressor is only used for an impact gun, tyre inflator, blow gun and schutz gun, it is not running constantly, runs every so often to top the tank up. I have ordered the rubber mounts and the hose is at the hydraulic shop to get a flexy pipe fitted.

I plan to install a baffle as shown in a picture and install some flexy ducting onto this routed to the compressor to make the most of the compressor fan

 

[normspanners]

Run a hose and put the air filter outside of the box or in the labyrinth so it at least draws cool air that will help with the cooling.

 

[the snooper]

BUT you have to careful it can increase it !! see quote below.
A labyrinth trap, speakers use the same but for your app putting sound deadening on each of the turns makes a HUGE difference. but a compressor doesnt have an exhaust actually I think you can get a head to receiver pipe silencer similar to turbo silencers.

HMMMMM id doubt you would hit the right port size for it to be resonant AND a road compressor does have an exhaust

 

[MattF]

I don't think I put enough thought into this project.

I think it's the opposite way; you seem to be over-thinking it. Just go with the damper mounts and flexible hose and see what you need to do from there. They'll likely be enough on their own.

If you still decide to go with an enclosure then, just duct tape a 4" or 6" flexible ducting from outside the enclosure to the intake vent on the compressor motor shroud and pop a couple or more of those vents in the top, or near the top, of the enclosure. The amount of air the motor fan is dragging through that ducting should sort circulation and keep things cool enough. It's easy enough to run a hose from outside the cabinet for the compressor intake if it's still getting a bit warm in there. If you make the cabinet from something like 3/4" MDF, that's fairly sound deadening on its own.

 

[pondy]

Small update, fitted rubber cotton reel mounts between the tank and pump, got a hydralic shop to modify my hose, fitted it all and its made no difference,

 

[Wallace]

That's a shame. Have you tried any of the 50mm board stood around it while running to see what the effect is?

 

[pondy]

I expected some thing but even though the db app on my phone is not accurate I got the same reading before and after. Going to start building enclosure tomorrow hopefully. Im going to extend the air filters outside the box when its complete, I did a mock up just adding a metre of hose betwen the filter and head, this reduced noise by 4db

 

[MattF]

What did your ears tell you? There must have been some notable difference in noise level. The dB meter will most likely show the exact same else very similar level if you point it directly at the actual compressor head/motor unit, but overall noise level must have been reduced somewhat. The ears are always a far better indicator than a meter.