Safely Linking 2 x Compressors To Increase Air Supply For Spraying

[JonnyAlpha]

Hi;

I have access to 2 x compressors which I was thinking of piggy backing in order to run a spray gun using a 'Y' connector. Each compressor has a short coiled Air Line so I was planning on connecting both of these to the 'Y' connector and then connecting a 10 or 15m Air Line from the 'Y' connector to the Spray Gun or Tool in use?

The 2 x compressors are as follows:
SIP Airmate T2/25-0: its a 2HP 25Ltr Tank (Nearest specs to this are the SIP Airmate TS2.0/25-0) free air delivery is 5.2cfm / Piston Air Displacement 8.0cfm, Maximum Air Pressure 118 PSI (About 8 Bar I believe).

Amac Magnum Beaver: its also a 2HP 25Ltr Tank, 8Bar (about 116 PSI) and a sign on the side of a cylinder head with 258 L/Min which converts to 9.11 cfm, but this too could be Piston Air Displacement?

Before I buy an Air Line and some connectors I'm guessing I need to make sure that the Air Line safe working pressure will be sufficient for this rig and possible future use if I ever get a larger compressor.

Question:

1. When dealing with Air Pressure do you add the maximum Air Pressure from each compressor to calculate the combined delivery i.e. 8 Bar + 8 Bar = 16 Bar?

2. Would this be the same for cfm i.e. 8.0 cfm + 9.11 cfm = 17.11cfm?

Or are there a whole load of other factors involved.

 

[Bill Edwards]

The pressure will not be any higher than the 118 psi that the highest pressure one produces. They're very well matched actually and will shut off almost at the same time.

For the CFM output, add the two together.
They should be safe to couple together. Both compressors will have a safety valve in place so if you added another compressor that ran at higher pressure nothing could actually go bang. Normal airline hoses and fittings are rated in excess of 150 psi so will be fine on any conventional setup.
If you get another compressor then you would want the pressure to be similar to the ones you currently have, this could mean turning the new one down or the existing ones down if they aren't close enough (i.e a new one could be set to 100 psi so you'd want to tweak the others down to match, or if the new one was 130 psi you'd turn it down a bit).
You want the compressors to come on at a similar time, but not the exact same moment as 2 or 3 motors stating up at the same time could test your electric supply.

 

[JonnyAlpha]

The pressure will not be any higher than the 118 psi that the highest pressure one produces. They're very well matched actually and will shut off almost at the same time.

For the CFM output, add the two together.
They should be safe to couple together. Both compressors will have a safety valve in place so if you added another compressor that ran at higher pressure nothing could actually go bang. Normal airline hoses and fittings are rated in excess of 150 psi so will be fine on any conventional setup.
If you get another compressor then you would want the pressure to be similar to the ones you currently have, this could mean turning the new one down or the existing ones down if they aren't close enough (i.e a new one could be set to 100 psi so you'd want to tweak the others down to match, or if the new one was 130 psi you'd turn it down a bit).
You want the compressors to come on at a similar time, but not the exact same moment as 2 or 3 motors stating up at the same time could test your electric supply.

Thanks Bill - so the net effect is i'll get around 17 cfm @ 118 PSI, (I think the Amac is slightly less than 9.11 so i'll probably get 16 cfm) with 50 Ltrs of Air Capacity?

 

[Bill Edwards]

The CFM figure could be at a lower pressure - manufacturer CFM figures are to be taken with a pinch of salt as they usually don't tell you what pressure the displacement is at. But otherwise yes, you'll have a 50l capacity, 118 psi and combined CFM figure of some sort!

 

[JonnyAlpha]

The CFM figure could be at a lower pressure - manufacturer CFM figures are to be taken with a pinch of salt as they usually don't tell you what pressure the displacement is at. But otherwise yes, you'll have a 50l capacity, 118 psi and combined CFM figure of some sort!

Works for me thanks :-)

 

[rtbcomp]

It's best to connect the tanks before the regulator and use a single regulator to supply your spray gun.

http://www.mig-welding.co.uk/spray-painting.htm

 

[Rig Pig]

When you connect 2 compressors one of the is normally lazy - the pressure switch will be a bit behind the lead unit, not too much of a problem to adjust but if you don't then one unit will be doing all the work on moderate air demand and may overheat. I assume the compressors are not 100% duty?

 

[JonnyAlpha]

It's best to connect the tanks before the regulator and use a single regulator to supply your spray gun.

http://www.mig-welding.co.uk/spray-painting.htm

I have some spare copper pipe in the garage 15mm I think and some joints so all I need is a regulator and some fittings to make the simple DIY solution, are the ball valves simply manual on / off valves? The simply DIY solution does not have any rises and drops noted to assist with water removal? The 2 x Compressors I have are oil free so I guess I don't need an oil reg?

 

[JonnyAlpha]

When you connect 2 compressors one of the is normally lazy - the pressure switch will be a bit behind the lead unit, not too much of a problem to adjust but if you don't then one unit will be doing all the work on moderate air demand and may overheat. I assume the compressors are not 100% duty?

Sorry what do you mean by '100% duty'?

 

[brightspark]

if they run continuously and the duty cycle is 100% thats fine if it was 60% they would overheat after a period of time

 

[rtbcomp]

............ are the ball valves simply manual on / off valves? The simply DIY solution does not have any rises and drops noted to assist with water removal? The 2 x Compressors I have are oil free so I guess I don't need an oil reg?

Ball valves are on/off. You will still need provision to drain the pipes and filter moisture out as you will get water condensing in them.

If you use 15mm that will be fine, the compression joints have 1/2in BSP threads on them, so it will be easy to connect to a 1/2 in regulator.

 

[JonnyAlpha]

if they run continuously and the duty cycle is 100% thats fine if it was 60% they would overheat after a period of time

Just tried to read up on what duty cycle is and still don't quite get it?? I have never run these compressors??

 

[rtbcomp]

With a compressor duty cycle is measured over a 15min period. 50% duty cycle would mean 7.5 mins on, 7.5 off. A 33.33% duty cycle would mean 5 mins on 10 mins off and so on. The duty cycle rating for your compressor should be in the literature or on the rating plate, although it seldom is!

 

[Rig Pig]

If your plan is to use the setup hard for hours at a time you would probably be better off selling the two smaller units and buying a larger belt drive unit that is built to take a bit of stick. They run a bit quieter too.

 

[JonnyAlpha]

I now have the 2 x compressors in my possession and the bad news is both have different size connections!!!!

Both have Female Quick Release fittings at the compressor but both are different sizes one is fatter and shorter than the other.

The SIP Airmate is the one on the top and the AMAC Magnum Beaver on the bottom. Looking at my March 2014 Screwfix, from the shape alone, it looks like the SIP Airmate is a UNI Connector and the AMAC is 1/4.

However to complicate things even more the SIP Airmate coiled hose has a female threaded nut about 1/2 Inch at each end as seen below:

Whereas the AMAC Magnum Beaver has male threaded nut about 5/8 Inch as seen below:

I need to be able to connect both these compressors together???

 

[JonnyAlpha]

With a compressor duty cycle is measured over a 15min period. 50% duty cycle would mean 7.5 mins on, 7.5 off. A 33.33% duty cycle would mean 5 mins on 10 mins off and so on. The duty cycle rating for your compressor should be in the literature or on the rating plate, although it seldom is!

OK I'm starting to understand now, is the Duty Cycle measured when the compressor is in use i.e. with your finger pressed on an air tool using Air or just when sitting idle?

 

[rtbcomp]

When the motor's running

 

[JonnyAlpha]

I now have the 2 x compressors in my possession and the bad news is both have different size connections!!!!

Both have Female Quick Release fittings at the compressor but both are different sizes one is fatter and shorter than the other.

The SIP Airmate is the one on the top and the AMAC Magnum Beaver on the bottom. Looking at my March 2014 Screwfix, from the shape alone, it looks like the SIP Airmate is a UNI Connector and the AMAC is 1/4.

However to complicate things even more the SIP Airmate coiled hose has a female threaded nut about 1/2 Inch at each end as seen below:

Whereas the AMAC Magnum Beaver has male threaded nut about 5/8 Inch as seen below:

I need to be able to connect both these compressors together???

Am I correct?

I have a plan to connect them together but I need to confirm the fittings. If the AMAC is a 1/4 Inch then I could rig up a water displacement system with a 1/4 Female Quick Connect which the AMAC 1/4 Inch Male will connect into? The SIP Airmate coiled airline could be screwed into a 1/2 BSP Male Thread?

 

[Rig Pig]

The fittings are easily changed, the thread behind the short one looks like 1/4 BSPT - eBay or any local hydraulic shop or even car shop should be able to sort you out.

 

[anjum]

If you've got both types of connectors it's worth fitting an outlet of each type. Keep the older type for air tools that need a lubricator and the later type for spraying and air fed mask, Fit the appropriate fittings on two airlines to keep them separate and avoid contaminating your paint with oil.