[TheForge] Compressor ratings

[Ray Miller]

Correct! As the true measure of the performance of the compressor, only 
CFM @ delivered psi is really important.

 If you are comparing a piston compressor versus a centrifugal versus a 
screw, HP is of no use.
The same issue of trying to get to volumetriuc flow at rated pressure is 
industry wide. In one of my past lives I was the Lead Engineer for GE 
Aircraft Engines test facility's compressor complex. (Total of 214,000 
CFM @ 650 psia). When we were looking at buying new machines we would 
have trouble getting CFM ratings that we could use for apples to apples 
comparisons. Some machines were rated at ISO conditions, something like 
a standard day, others used some other inlet temperature, pressure and 
humidity conditions. When I inquired into the variety of ratings from 
Ingersoll-Rand, Cooper Turbo, etc. they all agreed that the machine 
ratings were arbitrary and each company used the rating that made their 
machine look best.

So the simple answer for us smaller shop air compressor users is CFM @ 
delivered psi.

Sorry for the long answer. After spending many years working on large 
industrial compressors you get ate up with them.

Ray


Dave Brown wrote:

> At 21:15 08/11/02 -0400, you wrote:
>
>> I believe it to be consistent with many other measures of performance 
>> that are set by someone leading the field and the later entries have 
>> to use the same measure even if their product is not represented well 
>> by the measures:
>
>
> In other words, I should simply ignore the HP ratings and search out 
> the CFM/psi data?
>
>
> Dave Brown
> Heritage Smithing
> Green Bay, WI
> ABANA, UMBA, GoM, MODA, ARG
>
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