Need conversion of air supply at pressure/volume to liters/time
Need conversion of air supply at pressure/volume to liters/time
(OP)
I think we have a units misunderstanding on this project. The process designer says they need 5000liters/sec. This is for a approx. 180 hand tools on an automotive assembly line. I think this number has been normalized and is not 5000liters/sec at 6 bar. Our estimate for this amount of tools was 4025 cfm(MAX) at 80 psi. The building contractor is not supplying a large enough compressor for either but I can't compare the numbers and strighten this situation out. I am far removed(Rüsselsheim, Germany) from my engineering library in MI and have been searching every where for a conversion or something to determine pressurized air to normalized air. Any help would be deeply appreciated.
Thanks
Thanks





RE: Need conversion of air supply at pressure/volume to liters/time
1 Liter/Sec = 2.1189 Cu-Ft/Min
1 Bar = 14.5038 Lbs/Sq-In
5000 Liter/Sec * 2.1189 = 10,594.5 Cu-Ft/Min
6 Bar * 14.5038 = 87.0228 Lbs/Sq-In
Hope this helps!
RLJ
RE: Need conversion of air supply at pressure/volume to liters/time
The situation is very hectic and I wasn't very clear. I guess I am asking if anyone has spec't compressors and is there a comparison of a compressor suppling a volume of air at "atmosphere" versus suppling air at pressure? I realize there is an obvious load difference on the compressor. I guess I am tyring to figure out how these volume could be so different? I did get them into common units
Thanks,
Tim
RE: Need conversion of air supply at pressure/volume to liters/time
SCFM (atmospheric pressure). This is also known as "free air".
The ratio of compression for 80 PSIG is (80 + 14.7)/14.7 = 6.44, so for 4025 SCFM (if I understand you correctly), the volume at 80 PSIG would be 4025/6.44 or 625 cubic feet.
Spirax Sarco in the UK used to publish a booklet called "Compressed Air Practical Study PS 12". I've only ever seen the single copy I have. Even the Spirax Sarco people around here haven't seen any for years. I'd really like to get one with North American pipe dimensions rather than British Standard, so if anyone knows where I can get one, I'd really appreciate it.
RE: Need conversion of air supply at pressure/volume to liters/time
In my experience dealing with gas compressors and fans, manufacturers will normally rate their equipment for a particular flowrate in Actual CFM (acfm) which is takes into account the pressure. If the flowrate has been "normalized", I assume you mean stated in reference to a standard state (like 60 deg F, 1 atm). THis flow would normally be stated in SCFM (standard CFM). Anyway, the common denominator of the two quantities would be the MASS flow rate which is actually constant and is related to the ACFM by the DENSITY of AIR: If you want the units in ACTUAL cfm then you should use the density of air at 80 psig. To get standard CFM (scfm), then you would use the denisty at "standard" conditions.
i.e. mass flow (lb/m) = Q (Acfm) x Density (Lb/ft)@ 80 psig
I would use a table of AIr properties to obtain the denisty.
Hope this helps.
-JK
RE: Need conversion of air supply at pressure/volume to liters/time
RE: Need conversion of air supply at pressure/volume to liters/time
...is about 1/6 as much standard volumetric flow.
dns