Need assistance on compressor and plasma.

[AdrianH]

Bit of a story!

I am having fun with plasma cutting, and notice as one would expect, the higher the air pressure then the cleaner the cut. One manual suggests I should be needing 90 Litres air per minute at 4.8 bar, the nozzle has a 1mm hole.
An on line calculator suggests that at those settings I should only need around 56 litres air per min, but I can run out of air no problems.

So I have this old SIP nimbus 25025 compressor and it was getting hot, not unexpected really, poor thing was just not coping was never intended for continuous running (only meant for 2.5 mins at a time).

So I got a petrol compressor with a 100 litre tank, and I can run out with that!!!

So something must be wrong and I am wondering if it is my set-up.

I am running via two regulators, one is quite small same size as on the back of the plasma and this is set to 6 bar, this then goes to the one on the plasma cutter and this is set to 5 bar.

So my questions is am I making my compressors work even harder by doing this, should I go and by a bigger regulator and do it in one stage.

I did it because I thought it would be better to do it this way but wondering if by forcing the system to have a higher pressures in the compressor tank I am making it less efficient and wasteful?

Both the Sip and the newer petrol compressor have a 250 litre displacement cylinder



Advice gratefully received even if how to link both units together?

Adrian

 

[123hotchef]

if they both work then link them together yes that should sort out you air needs

what u cutting and how long you cutting for

 

[AdrianH]

A job I was cutting today was just over 10 metres cutting distance on 1.5mm mild steel, travel speed for me is quite slow at a max of 900mm per min, 46 pierces and there is an after flow of air after cutting of 2.5 seconds, etc.
11.5 minutes of cut time or there a bout.

Thinking of getting one of these from machinemart to replace the two currently in use any thoughts



Adrian

 

[123hotchef]

i dont think swapping the 2 regs for that 1 reg is the answer, joining the 2 compressors together would help thing very much, I have done just that

 

[123hotchef]

i would use that reg and link both of the compressors into it, is it 1/2 ports?

 

[brightspark]

there half inch and can use the 3./8th reducers fitted on picture

 

[AdrianH]

Would I not get a problem with both compressors running into one?, may sound daft to ask, the 100 litre tank has one of these on it from the pump.


Sorry it is a bit blurred taken with phone, but it is direct from the pump head before a one way valve into the cylinder, could I put the smaller compressor into that, or should I parallel the outputs?

Adrian

 

[gaz1]

i think you need to add more storage of air cylinders if your running out of air with just 1 100 litre tank and another also running and not able to keep up then adding another tank should allow longer time for cutting however draw back is your compressor will run for extended times when filling or refilling the system back up

i have a 170 tank with the pump but that used 3 phase i dont have the motor anymore but with knowledge of the garage even that will run out of air very quickly more so at 22 cfm

 

[AdrianH]

Ok I will look to parallel the outputs of the tanks, I assume at these points there are no one way valves, the thing that got me is that 90 lpm is 3.2cfm the compressors I thought should have coped with that.

I will need to get a decent silencer on the the petrol engine.

Adrian

 

[123hotchef]

you could always add extra storage like I am doing now with a gas cylinder or 2