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Unread 01-02-2015, 00:07
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Re: Help Calculating time to recharge air tanks

Quote:
Originally Posted by Michael Hill View Post
I'm not sure I trust Viair's CFM data...has anyone actually measured it. It doesn't jive mathematically if you look at the 0.5 gallon and 1.0 gallon performance...(assuming my calculation is right). If there's a math mistake please late me know.
I'm not sure exactly what you're doing in your spreadsheet, but I certainly do find it suspicious that you wind up with a temperature of over 1000R (550F). I believe that this temperature would cause plastic tubing (and maybe tanks) to soften and rupture. This may be correct for an adiabatic compression of air, but there is certainly some temperature equalization taking place.
I did the calculations based on constant temperature (not right, but probably closer), and came up with 2 minutes and 9 seconds for 0-120 on a 1 gallon tank. This is still shorter than Viair's 3 minutes, but a good bit closer. There does seem to be a disagreement between the "performance" and "fill rate" data.
Attached Files
File Type: xlsx Pneumatics-1.xlsx (181.7 KB, 13 views)