advice sought for air compressor

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flat6buster

flat6buster

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Hi - can anyone give me some pointers on what to look for when I buy an air compressor. It is to run a small piece of machinery that requires a 30 litre/minute supply.

It will be used inside so needs to be quiet and electric I guess.

Anything I should look for? Just go to machine mart?

Should I overspecify in case I get something else to run off it (which may happen - I may need 4 times the output in a year or two's time) or just get the basic and see how it goes?

Finally 3 phase or single phase? I have both available but I would probably have a natural preference for single phase as it would be more saleable should I ever want to gt rid and I think my air requirement is pretty paltry so a huge 3 phase thing would feel like using a sledgehammer to crack a nut.

Thanks for assistance - I've never had one so any input from you experienced folk gratefully received.
 
For a start, it's unlikely to be particularly quiet when running. I bought a compressor earlier this year, well, actually, I bought two.

The first was a cheap machine from a website offering lots of compressors at seemingly good prices, etc... However, when it arrived, I quickly found the quality to be rather lacking. I didn't even bother starting it up before sending it back for a refund.

The second machine is a Workhorse belt driven machine. It's far, far better. Yes, it cost considerably more, but the tank is UK made, although the company is Italian. It is pretty quick to fill, which cuts down on the time that noise is generated.

My machine is single phase, but the do a range of 3 phase machines, these being the bigger, higher capacity models.

I think, for 30l/min you will probably need a 3 phase, larger machine, so it's not going to be cheap. What machinery are you looking to run?
 
thanks Chris, I am running a liquid filling machine which is essentially a little hydraulic pump.
 
Take a look at FIAC compressors. Their UK company is Wilkinson Star - that's what mine is. I find the machine well designed and reliable, although my one does seem to eat 13 amp fuses!
 
The usual " men" rules apply here:

"We expand the job to fit the tools we have bought thereby ensuring that we need more and bigger tools"

Small compressors get breathless quickly and this can be a very real issue if you require a constant steady air flow? By bigger than you require and you will be safer.

They are usually really noisy!!

I have one and love it but I wish I had bought bigger. It will not crack off torqued up wheel nuts. But of you crack them first it will take them off with ease. Using a hammer wrench it will make short work of most nuts and bolts and save your back from endless pain.
 
brucemillar said:
The usual " men" rules apply here:

"We expand the job to fit the tools we have bought thereby ensuring that we need more and bigger tools"
Click to expand...

Love it!

As Tim The Toolman used to say in the American Sitcom Home Improvement

More Power, More Power.....
 
Bear in mind that if it's for home use a three phase device may cost a lot extra to have a three phase supply installed.

If your home already has a three phase supply then I doff my hat to you sir!
 
flat6buster said:
Hi - can anyone give me some pointers on what to look for when I buy an air compressor. It is to run a small piece of machinery that requires a 30 litre/minute supply.
Click to expand...

Is that the same as 1CFM?

If so a dental compressor is the one for you, small and silent.

No need for a 3 phase hydrovane I'd have thought?
 
In general, you get what you pay for.

Small direct drive compressors are noisy beasts, but for the occasional user, are probably OK. I bought a small compressor (Parkside PKO 400) at Lidl as it was cheap enough to be considered a disposable item:

Technical data
Mains connection: 230 V ~ 50 Hz
Motor rating kW: 2.2 kW
Operating mode: S1
Compressor speed min-1: 2850
Operating pressure bar: max. 8
Pressure vessel capacity (in liters): 50
Theoretical intake capacity (l/min): approx. 400
Effective delivery rate at 7 bar: approx. 160l/min
Sound power level LWA in dB: 97
KWAuncertainty: 4 dB
Protection type: IP20
Weight of the unit in kg: 44
Oil (15W 40): 0.3 l


It is 'grunty' enough to loosen wheel nuts (using a decent quality Ingersoll-Rand windy gun) and small enough to move around with reasonable ease - e.g. dragging up the garden to spray the shed. The air tank is only 50 litres and that's probably as small as you'd want to go if using any sort of 'greedy' air tools as the compressor will end up running a lot to keep the tank topped up. For example, I usually get about 2 sets of wheel bolts loosened before the compressor cuts in.

Belt driven compressors are much better in terms of performance and durability, but they are more likely to be pretty expensive and hefty beasts more suited to permanent installations. Three phase power is likely to be a requirement for bigger models too, so bear that in mind when considering costs.
 
nick mercedes said:
Is that the same as 1CFM?

If so a dental compressor is the one for you, small and silent.

No need for a 3 phase hydrovane I'd have thought?
Click to expand...

I reckon it is the same. I'll google dental compressor. I like the idea of silent!
 
First thing is to decide how much air you need and double it. The reason for this is that manufacturers tend to quote a displacement figure for output, and not Free Air Delivery (FAD) which is the one that matters. This is usually 1/2 - 2/3 of the displacement figure. Not only that, if you do decide to increase your needs, you may as well just go over the top initially and not have to worry about a replacement a couple of years down the line

Most compressor adverts give their figures in CFM, so for what you need (30 litre/minute) this works out at just over 1cfm, so pretty small by industrial standards.

For this output, 3 phase won't be necessary I wouldn't have thought, though if you want a quiet one, try to go for a belt drive as opposed from the direct drive linked to above by merc85 as these are loud, especially when constantly running.

If you want really quiet, have a look at Dental supplies (Bambi for example) though these are certainly not the cheapest.

Like Bruce says, buy big and you shouldn't have any issues for a few years to come. I have an old Wolf thing in the garage (14cfm/90 litre tank) and it's not big enough for my new found needs. It's also pretty loud though in a separate room.
 
If you have a 3 phase supply and require a reasonably large machine I would be inclined to use 3 phase- with 2 motors of the same hp output the 3 phase will be simpler smaller/lighter and more efficient in terms of power consumption than the single phase. Like for like --above a certain hp the 3 phase may actually be cheaper to buy also.
 
nick mercedes said:
T-NADO Air Compressor [COM] - £310.00 : MR. Dental

4cfm, silent, only 50% duty cycle though
Click to expand...

Yes just saw that. I don't mean to sound DELIBERATELY dim, BUT; I understand a 50/50 duty cycle means it cant be run all day every day. I need it to run continuously for 4 to 6 hours then not at all for a day or two, then 4 to 6 hours again.

A 50:50 duty cycle could mean run it only for 4 hours in an 8 hour shift, 7 days a week, or it could mean use it all day one day and not at all the next. Or it could mean run it for 5 minutes then give it 5 minutes rest?

Could any of you brainy types clear my confused mind?
 
flat6buster said:
Yes just saw that. I don't mean to sound DELIBERATELY dim, BUT; I understand a 50/50 duty cycle means it cant be run all day every day. I need it to run continuously for 4 to 6 hours then not at all for a day or two, then 4 to 6 hours again.

A 50:50 duty cycle could mean run it only for 4 hours in an 8 hour shift, 7 days a week, or it could mean use it all day one day and not at all the next. Or it could mean run it for 5 minutes then give it 5 minutes rest?

Could any of you brainy types clear my confused mind?
Click to expand...

It would be fine for your needs.

Given it's a 4cfm machine and you only need 1, it will lead a stress free life.
 
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