john banks

Looking for a 5CFM FAD (say 7-8 CFM displacement) 240V air compressor which is not as quiet and expensive as the 50dB fridge types, but not deafening like the 97dB cheapie direct drive types. Many of the "professional/industrial" types which are piston but belt driven don't quote their noise level. Those that do seem to lie, we ordered a Sealey that was over 96dB at 1m using an iPhone (I know, but it is about right) whereas the manual quoted 72dB(A), but didn't say it was probably at 7 or 10m or some other trick.

Budget up to about £750, maybe £1000. Oil free might be better as it could otherwise oil up optics, but we can filter.

Are we asking too much for this combination? Something that you can hold a normal conversation next to would be good as we'll locate it to an upstairs eaves cupboard above the workshop and hopefully 15m away where a neighbour's house is it won't sound any louder than their oil fired boiler, and it will be easy to hold a conversation in person or on the phone in the workshop.

ALi-B

iTrader: (1)

Unfortunately I think its case of getting what you pay for I think your best bet is trying to find one second hand.

You can have lots of cheap air with lots of noise, (piston compressor)
Quiet and cheap, but hardly any air, unless doubled up, then it gets expensive (rotary fridge type compressor)
Or quietish, and more air, but expensive (screw/rotary/vane compressor).

The latter of which I think you'll struggle getting in single phase.

We have the latter (larger and in three phase), and TBH it is quieter than the equivelent piston type. But its cooling fan is almost as loud as the compressor, which is comparable to standing next to an idling motorised mini street sweeper/vacuum. But it is housed in a small store room and once the door is shut I can barely hear it. The main beauty is its very smooth and doesn't vibrate, the old piston V-twin one used to shake everything around it..

So maybe part of the answer lies in somehow sound proofing the room its stored in? (don't forget isolating it from the floor joists if upstairs).

andy97

iTrader: (1)

Run it from another building or a shed outside and use a long airline

stuart2008sti

iTrader: (1)

John what are you going to use the compressor for,I will give you some options of motor and reciever size.

www.1stsupplieswales.co.uk is my website.

john banks

It is for a laser cutting machine. When we cut wood, if we use 1-2 bar the charring disappears and it dramatically reduces the clean up time after a job. The air is being introduced just below the final lens, so it also keeps the lens clean, hence the preference for oil free if possible. The nozzle size if 4.5mm so that may or may not tell us what airflow we need at 1-2 bar?

Present compressor is a Hailea ACO 500 which is designed for an aquarium (continuous duty, no receiver, oil free), it has decent flow but only runs about 0.4 bar, and through the 4.5mm nozzle doesn't blast away the smoke from the cut well so the wood chars a bit and resin splatters. You can clean or sand it, but it take time. On my shorter focal length lens I can reduce the nozzle to 2mm and this dramatically improves the air velocity even with the small compressor. However, a longer focal length lens gives a straighter cut in thicker wood, but we can't narrow the nozzle because the laser beam would hit it as it is wider with this lens.

So we need more air.

We have a 0.25m^3/min (not sure if displacement or FAD, that is what it says on its plate) Chinese compressor which says it is 2.2kW but occasionally blows a 13A fuse on startup (I could give it a higher fuse rating on a spur I suppose). It is belt drive and has oil and water filters, and the results are good, but the sound is like the horsemen of the apocalypse. Putting it in a soundproof area might be possible, but I'm sure we can do better.

stuart2008sti

iTrader: (1)

Hi John

Because the budget is upto £1000 you have no option but go for a piston compressor which are very noisy,you can enclose this to reduce the noise but this will only go so far.If possible try and pickup a second hand screw machine.If you only have single phase 3hp is the max or 6hp with a duplex piston machine.Screw machines start around 3hp if you can find one second hand and service parts are not expensive if you go for non oem items which are on most occasions made for oem with different numbers on them which we have full access to.

Thanks

Stuart

john banks

Thanks Stuart. I fitted the supplied filters to the noisy Chinese compressor and it has made it much quieter, plus I've hidden it away in an outbuilding and ordered tube to connect it, so will see how that goes with some slow blow fuses or failing that a 16A feed.