Small screw compressors - Eastwood QST alternative?

Hello,

I've had fun borrowing and playing with small 1-2hp piston compressors to run my new Speedio mill.

I'm looking for something like the Eastwood QST scroll, but I'd prefer it not be made in China. My shop space is tiny so the Eastwood 30 Gallon tank would be a nice fit relative to a 60gal horizontal tank. Is there a comparable 3-5hp screw on a 30-40 gallon tank that I should be looking at?

Thanks

Take a look at Kaeser. The benefit with them is that you can add more compressors later and they will all work together or in shifts, however you want to set it up.
We have a total of 4 in two buildings for a whopping 80 hp.
They aren't cheap, but they will probably outlast you.....
IIRC they are made in Germany.

Compaire hydrovane from the UK
Mattei from Italy

atlas copco gx4ff . No crazy computer like some of the others i've had thru here

Are Chicago Pneumatic QRS screw compressors decent? They look to have the same enclosure and layout as the Quincy, and and very similar to the Atlas but cost a bit less. Is it B-grade components, made overseas or just a different market direction (more automotive) and thus price points?

azander said:

Are Chicago Pneumatic QRS screw compressors decent? They look to have the same enclosure and layout as the Quincy, and and very similar to the Atlas but cost a bit less. Is it B-grade components, made overseas or just a different market direction (more automotive) and thus price points?

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They are the same compressors, all built in China by AirTec. Atlas Copco is the parent corp of all. AFAIK the only differences are in the electronics and enclosure designs and insulation, with Atlas Copco being the "high end" version.

The larger Atlas Copco's are built in Europe. The way to tell is if the oil cooler is mounted horizontally, it's a European compressor.

I have a GX5FF Atlas Copco, and I chased an oil leak around till it drove me crazy, then I found the bad O-ring and all has been fine since. That was over a year ago, I haven't had to add any oil since replacing the O-ring.

You can go all the way down to 3HP on these, but I would probably recommend at least 5HP if you have the power.

If I had it to do over again, I would not buy an integrated chiller, I would get a standalone unit. But I would not run without a chiller either way.

Atlas Copco, Quincy, and CP will all have a 53 gallon tank if you buy a tank-mounted unit. If you use much air it pays to have an external dry receiver (60 or 80 gal) close to the machine so you are not short-cycling the compressor all day long. I run 2 x 80 gallon dry receivers in my system, and cycle the compressor 3-4 times an hour for about 6 minutes per cycle.

guest said:

They are the same compressors, all built in China by AirTec. Atlas Copco is the parent corp of all. AFAIK the only differences are in the electronics and enclosure designs and insulation, with Atlas Copco being the "high end" version.

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Are they decently made for the price? I was looking at the DV Systems A5, which I understand is Made in Canada, however even the sales person dissuaded me from that one due to reliability or serviceability issues.

I looked at Hydrovane from Gardner Denver. They seem to be louder with their open top. Is rotary vane good for this, or is screw a bit better for intermittent start/stop use?

ChipSplitter said:

Take a look at Kaeser. The benefit with them is that you can add more compressors later and they will all work together or in shifts, however you want to set it up.
We have a total of 4 in two buildings for a whopping 80 hp.
They aren't cheap, but they will probably outlast you.....
IIRC they are made in Germany.

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We purchased two Ingersol Rand unigy VFD rotary screw compressors as replacements for earlier units. MAJOR piles of pure junk.
We got to know the I/R warranty guy real well, when the warranty ran out we dumped both of then to the tune of 36,000 dollar loss. Nobody wanted to touch them in a trade and I understand why. I purchased Kaesers and we are now going on year 6 and have never been happier.Now we only use Kaesers for our rotary screw needs.

I can vouch for the Atlas Copco quality at least in the larger units. I installed the GA30 model at my old employers, with bypass system, oil filters, and a Parker external dryer. 200-gallon receiver, 2-inch lines out into the plant.

Their application requires 24x7x365 and that is exactly what it has been doing for the last 4 years. When it finally burns up, it will have paid for itself anyway (air compressors are kind of consumable for them)

I'm going to ask a stupid question.

Besides NOISE, is there any other advantage to a scroll or a screw compressor?

How are they on energy consumption compared to a noisy piston compressor?

Bobw said:

I'm going to ask a stupid question.

Besides NOISE, is there any other advantage to a scroll or a screw compressor?

How are they on energy consumption compared to a noisy piston compressor?

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My theory on that-- the screws are more efficient because they aren't hammering a piston up and down, they run in one direction all the time. IDK, mebbe I'm wrong.
Also they last longer for the same reason.

Bobw said:

I'm going to ask a stupid question.

Besides NOISE, is there any other advantage to a scroll or a screw compressor?

How are they on energy consumption compared to a noisy piston compressor?

Click to expand...

My experience on that is, they are better on the electric bill, but they are also louder -- think like a shop-vac going all the time. BUT maybe that was only the screw compressors that I've used. Maybe other ones are quieter if they don't have to run continuously.

From the numbers I've worked up screw compressors are a little bit less money to *run* when outputting the same CFM of air... However running a screw compressor can cost *significantly* more than a piston if you're in a low demand application because most screw compressors will run unloaded for some period of time after reaching the pressure set-point.

You would think that they wouldn't pull a lot of current when running unloaded but I was quickly disabused of that notion by just putting a clamp meter on mine. It pulls 11A loaded and 9A unloaded. So if you're only starting it 4-5 per hour to fill the tank, and then it's running another couple of minutes each time unloaded then the unloaded running time could quickly double the electricity cost relative to a piston compressor supplying the same air, as the piston will run much less time.

The reason they run unloaded is because screws are designed for high demand applications and if they stopped/started the motor all the time it would exceed the allowable number of starts per hour of the motor, and it would burn up from overheating. Worth noting too that startup is potentially the highest wear part of the cycle for a screw compressor 'air end' (the bit that actually does the compression) because it's the time when it has the least oil in the head. So running in a low demand application could reduce the number of hours the compressor lives for (like highway miles versus city miles on a car). However screws are rated for such long lifespans I don't think this will really be an issue.

I bought a used 10HP Kaeser SM10 for a stupid small amount of money. It has 60K hours on it and still runs like a champ after a service. If you've never stood next to one it's worth noting that they are not quite as quiet as you'd imagine. There is a really big fan inside that runs whenever the compressor is running and it's the largest source of noise. Mine is 75db when running. I found a setting on mine that drastically shortens how much it runs after each cycle and overall I'm happy with it.

Coming from a 5HP dual stage piston compressor that was close to 100db the screw is a huge improvement, but it's not as quiet as I had imagined it would be given how others talk about them.

The reason I went with the Kaeser is because once a week or so I do a fair amount of sandblasting which uses a lot of air.

If you don't have large air demands then I think something like the Eastwood will be:
- Quieter
- Simpler
- Smaller
- Cheaper to buy
- Cheaper to run

When compared to a screw, or piston compressor. Downside is that the long-term reliability has not been proven yet. I have looked at a *lot* of quiet compressors while trying to get rid of my 5HP piston, and if I hadn't found my deal of a Kaeser I would have bought a pair of the Eastwood compressors.

EDIT: just saw in another thread that apparently a clamp meter can give false readings when a motor is not loaded up, because the motor could be pulling high current but with a low power factor. Take the idea that running unloaded is expensive with a grain of salt, but it's definitely still going to cost more than a machine that is not running after it hits the pressure set point!

I have the three horse single phase 30 gallon version of this

Scroll Tankmount Systems | POWEREX

made in USA but how much who knows.

Several years ago there was a scroll compressor being made in the Chicago area. Scrollex I believe. I looked at buying their CMM after they ceased operation.

Bobw said:

I'm going to ask a stupid question.

Besides NOISE, is there any other advantage to a scroll or a screw compressor?

How are they on energy consumption compared to a noisy piston compressor?

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For me, the less noise alone was worth the price of admission.

But also an expectation of thousands of hours of clean reliable air without excessive fussing around with compressors. They are more expensive to own, oil and filters are expensive and you have to do the services on schedule.

I replaced 2 5hp recips with one 7.5hp screw, so I can't really make a good comparison on power consumption.

clean air, and no special oil needed.....:
Kobelco- Kobe Steel Group

digger doug said:

clean air, and no special oil needed.....:
Kobelco- Kobe Steel Group

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How important is the "Special Oil" in a screw compressor? Can AW46 or P&O46 be used instead? Engine driven portable.

aarongough said:

If you don't have large air demands then I think something like the Eastwood will be:
- Quieter
- Simpler
- Smaller
- Cheaper to buy
- Cheaper to run

When compared to a screw, or piston compressor. Downside is that the long-term reliability has not been proven yet. I have looked at a *lot* of quiet compressors while trying to get rid of my 5HP piston, and if I hadn't found my deal of a Kaeser I would have bought a pair of the Eastwood compressors.

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Seems like there's no clear alternative to the Eastwood - decently quiet and the small footprint helps. I suppose it's a decent start. If it doesn't hold up after the warranty period, I'll probably invest in a Kaeser.

dkmc said:

How important is the "Special Oil" in a screw compressor? Can AW46 or P&O46 be used instead? Engine driven portable.

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The manuf's all made a big deal out of using their "special oil"....so I dunno.

azander said:

Seems like there's no clear alternative to the Eastwood - decently quiet and the small footprint helps. I suppose it's a decent start. If it doesn't hold up after the warranty period, I'll probably invest in a Kaeser.

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I guess you didnt see the link

USA made

Scroll Tankmount Systems | POWEREX