Quiet compressors

[California]

... but wearing out or over working these small non continuous duty multiple motor/ pumps could be a reality.

So true! My cheap HF 10 gallon / 2 hp (claimed) compressor was rated more cfm than their inexpensive die grinder. Ha. First use, the die grinder exhausted the air and slowed to a crawl. I smelled smoke and the compressor was smoking severely - but it never shut off, it just ran and strained to get the pressure back up. I think in a few seconds more it would have burst into flames. I haven't tried the die grinder since. Beware HF's bogus hp and cfm ratings. They don't declare rated life, but it can't be very long. Less than hours if it were run continuous at low pressure like I did.

 

[sd455dan]

So true! My cheap HF 10 gallon / 2 hp (claimed) compressor was rated more cfm than their inexpensive die grinder. Ha. First use, the die grinder exhausted the air and slowed to a crawl. I smelled smoke and the compressor was smoking severely - but it never shut off, it just ran and strained to get the pressure back up. I think in a few seconds more it would have burst into flames. I haven't tried the die grinder since. Beware HF's bogus hp and cfm ratings. They don't declare rated life, but it can't be very long. Less than hours if it were run continuous at low pressure like I did.

Ha Ha I have like 3 of their d/a sanders
1 of the reasons I needed all that air is HF's da sanders eat like twice the air of what a quality D/A does, come to think of it the 1/4 die grinders are Real air Hogs to.

ps. used the wifes HF compressor (about the size you have) to air up some tires on my kids car out by the barn. The compressor was like 50% full so I plugged it in and it just growled at me - then noticed it had a little unloader air valve on top of the pump . pushed that and away she went, just not very confidence inspiring.

 

[strantor]

Interesting concept, a couple concerns- and I am sure I am probably being overly critical on this...


If using high demand tools for long periods (as an example a D/A sander) will likely push them all into continuous duty at the same time.



Most belt driven oil type pump compressors are rated for continuous duty (both the pumps and motors)
So if needed you can and likely will- run them non stop, don't have to worry about having to shut off the compressor to save either the pump or motor or being in the middle of an important job -say painting and have the compressor (gasp) turn off- to protect itself.

jmo but that would bother me more than the noise..

I run 2 parallel compressors ( IR 5 hp 60 gallon uprights) when needed.
They are not super quiet but run very smoothly and not what I would call irritatingly loud but surely louder than the small quiet compressors together. also provide 24+Cfm @90 psi If both are turned on.

Maybe these new direct drives are long lived but what I have been able to find for durability/ quoted lifespan it doesn't look real good...


15 cfm @90 psi that you quoted,using them in parallel sounds good, right up with the belt driven units

but wearing out or over working these small non continuous duty multiple motor/ pumps could be a reality.

I checked out California Air 4 hp quiet compressor for $1700....


it has a listed life cycle of 3000 hours... and it's competitors at less than 1500 hours
that is about about 1/8 of an average Quincy, IR or other name brand oil type belt driven compressor

if that is how long lived a $1700 direct drive oil less Quiet compressor is-

What can be expected out of a few sub $200 units hooked together?

California air quotes their small inexpensive line compressors at 3000 hours to which is a Good thing, with California Air asserting some competitors are less than 250 hour life cycle.

3000 hours to have a nice quiet compressor is probably worth it for many versus 25-50000 hours for a good brand name belt drive oil type that is louder.

the only thing that i would suggest with your plan/ build would be to buy compressors with a lifetime hour spec like California Air quoted so you can get decent service life from the multi compressor build.

Good points and I agree. I have not totally ignored compressor life, and another option I'm keeping on the back burner is this scroll compressor from Eastwood, with 100,000 hr lifespan. I'm not totally averse to spending money, but I try to avoid it when possible. If this multi-compressor scheme doesn't work out, I'll probably buy that. The good thing about the multi-compressor build is that I can ease into it. I can start out buying one or two compressors @ < $150/ea, measure their performance, compare to the MFG's advertised ratings, test for spontaneous combustion at continuous duty, all that, with just a little bit of money up front. It should be obvious at some point well before the full-blown 5-6 compressor rig that this isn't going to work, and I can reverse course before much is lost. If they crater, then all is not lost. I'll have an extra 10-15gal worth of reserve storage tanks to connect up to my new scroll compressor.

 

[shooterdon]

Good points and I agree. I have not totally ignored compressor life, and another option I'm keeping on the back burner is this scroll compressor from Eastwood, with 100,000 hr lifespan. I'm not totally averse to spending money, but I try to avoid it when possible. If this multi-compressor scheme doesn't work out, I'll probably buy that. The good thing about the multi-compressor build is that I can ease into it. I can start out buying one or two compressors @ < $150/ea, measure their performance, compare to the MFG's advertised ratings, test for spontaneous combustion at continuous duty, all that, with just a little bit of money up front. It should be obvious at some point well before the full-blown 5-6 compressor rig that this isn't going to work, and I can reverse course before much is lost. If they crater, then all is not lost. I'll have an extra 10-15gal worth of reserve storage tanks to connect up to my new scroll compressor.

That thing is $2k!

I like your concept of multiple units and I do not need a lot of compressed air. My cheapie, and loud, oil less unit stopped working a couple of weeks ago so I need to fix it or replace it. Buying a couple of smaller units and tying them into that tank makes sense. I will not worry about the control system you are considering. Not a bad idea but overkill for my use. If both compressors turn on at about the same time, they will have about the same hours on them anyway. KISS

BTW, it may make more sense NOT to try and balance the hours. There would be more frequent replacement of the first one or two units in your system, but the remaining units will have less hours and more reliable redundancy. Just another way to look at it. And I suspect for 80% of the time, two units will handle the load.

 

[Oldoak]

Yep, what strantor plans to do makes absolutely no sense to me. There are much better alternatives that I would pursue.

But like I always said: "To each, their own". What ever we as individuals makes us happy.

 

[strantor]

That thing is $2k!

I like your concept of multiple units and I do not need a lot of compressed air. My cheapie, and loud, oil less unit stopped working a couple of weeks ago so I need to fix it or replace it. Buying a couple of smaller units and tying them into that tank makes sense. I will not worry about the control system you are considering. Not a bad idea but overkill for my use. If both compressors turn on at about the same time, they will have about the same hours on them anyway. KISS

BTW, it may make more sense NOT to try and balance the hours. There would be more frequent replacement of the first one or two units in your system, but the remaining units will have less hours and more reliable redundancy. Just another way to look at it. And I suspect for 80% of the time, two units will handle the load.

Eastwood does sales from time to time. I should have bought that unit when I first saw it; it was much less.
You might be on to something though. I could make everything much simpler by having a "designated failer." Put a red X on one of them, set its pressure switch to turn on at 125PSI. Set the next one to 120, and the next to 115, and so on. The #1 compressor fails first, and then red X gets painted on #2 compressor....

I see the merit in it but I'm not sure I'm sold on it. I will give it some more thought.

 

[ultrarunner]

Scroll Technology or sometimes called Claw has been around for a long time for a price.

I remember seeing my first one many years ago at a sandblaster... it was quiet and provided all the air needed and it was cleaner air too...

Overkill for most but if you have a serious shop with air tools, painting, etc AND long life, sound and space are issues... scroll is very attractive.

The Eastwood offering is made in China and why I suspect it is available for under 2k price plus $250 flat rate shipping.

 

[rScotty]

Eastwood does sales from time to time. I should have bought that unit when I first saw it; it was much less.
You might be on to something though. I could make everything much simpler by having a "designated failer." Put a red X on one of them, set its pressure switch to turn on at 125PSI. Set the next one to 120, and the next to 115, and so on. The #1 compressor fails first, and then red X gets painted on #2 compressor....

I see the merit in it but I'm not sure I'm sold on it. I will give it some more thought.

That is a clever theoretical idea and I thank you for that. But I don't think it applies in today's real world of pumps and complicated mechanical devices. The idea might work for a very simple single motion device.....something like a single spring undergoing repeated stress to failure.

For a "designated failer" idea to work, the main reason for failure has to be running time. That's makes interesting math, but it doesn't translate well into the world of real mechanical devices. The reason is simply that most mechanical devices just aren't that accurately or consistently made....and that goes double for the cheap ones.

I've been doing mechanics for a long time, and have found that operating hours in the real world is just as often an indication of reliability as of failure. It would be nice if "new" equalled "perfectly good", and if we could then say that operating hours was an indication of lifespan....but it just isn't true except in the most general sense.

I do agree with your theoretical point, that in a very large and consistent mechanical population - which I doubt these cheap pumps represent - you should begin to see some correlation between failure and operating hours after sorting all the other types of failure. But I think that it would be accidental if that correlation held for five pumps.
thanks for the interesting idea,
rScotty

 

[LittleBill21]

for you guys with the dual compressors, i did the same thing but made it portable, the concern though, is they were connected after the regulators, so i bought a one way air valve, because i've been told back pressure on a regulator output will make them explode. i used it a couple times and it worked ok. im happy to hear the cheap air impacts use more air, i am switching out compressor's because i can't run the impacts, to much air loss through the regulators.

 

[strantor]

That is a clever theoretical idea and I thank you for that. But I don't think it applies in today's real world of pumps and complicated mechanical devices. The idea might work for a very simple single motion device.....something like a single spring undergoing repeated stress to failure.

For a "designated failer" idea to work, the main reason for failure has to be running time. That's makes interesting math, but it doesn't translate well into the world of real mechanical devices. The reason is simply that most mechanical devices just aren't that accurately or consistently made....and that goes double for the cheap ones.

I've been doing mechanics for a long time, and have found that operating hours in the real world is just as often an indication of reliability as of failure. It would be nice if "new" equalled "perfectly good", and if we could then say that operating hours was an indication of lifespan....but it just isn't true except in the most general sense.

I do agree with your theoretical point, that in a very large and consistent mechanical population - which I doubt these cheap pumps represent - you should begin to see some correlation between failure and operating hours after sorting all the other types of failure. But I think that it would be accidental if that correlation held for five pumps.
thanks for the interesting idea,
rScotty

Good point, I agree. And this applies as much to my original idea (tracking run time on all compressors and forcing them to run an equal amount) as it does to the "designated failer." So maybe the best way to go about this is the simplest way. Just connect all the compressors in parallel straight out of the box without any adjustments to pressure switches, and let them kick on, run, shut off, last forever, or prematurely fail in whatever order they are destined to, as predicated by their inconsistent quality.