3 Stage Compressor Capable of 6000 PSI?

[CraigAClark]

When I worked for a Mako distributor here in Florida, he had a client that had a Coltri Compaq 90 that was running it to 6000 psi. This was a fire dept. that claims Coltri USA told them it was made for that final pressure. When I was sent to deal with a problem, I found that one of the main bearings was destroyed and the machine was toast. I was wondering if anyone else had heard of this 6000 psi working pressure claim by Coltri?

Craig

 

[iain/hsm]

Yes its pretty standard practice with compressor salesmen.
The salesman looks at the pressure gauge sees 6000 psi written on the dial
So of course its good for 6000psi

And sadly the customer is just too ignorant as to know any difference.

But yes 6000psi is not a problem, with a 3 stage or even a 2 stage compressor just not from ambient
pressure and not (IMHO) with the same piston sets as an ambient air scuba compressor model.

Not unless that is the first stage can take around 6 to 10 bar inlet pressure minimum then its quite possible using 3 stages.

The additional rod loading on the first stage can always be compensated to match what it used to with an ambient pressure model by reducing the piston diameter and ditto for the remaining stages.

The reduction in flow from reducing the 1st stage diameter can be compensated by making the first stage double acting ie by compressing both in the piston upstroke and the downstroke you double the flow back again etc etc or if they are cheating then simply jack up the RPM

But yes Coltri as anyone else can claim 6000psi discharge pressure with a 3 stage machine
just not (IMHO) with an 1 bar ATA ambient air pressure intake.

The rest is down to engineering capability experience and skill to make it reliable and maintainable and in that area sadly they as most others scuba compressor suppliers do not have the skill sets to make it happen........for long.