I agree w/ u bill... sound like mind twisting 4 me, so whats the simplest formula?
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How Big An Air Tank?
A rule of thumb for air compressor receivers is that they should have 1 gallon of capacity for every CFM of compressor output. Therefore, since a 25 HP compressor can theoretically generate about 100 CFM at 90 PSI, the receiver for that compressor should be 100 gallons in size.
The receiver?s size relative to the downstream demand, will allow the compressor to build up a reservoir of compressed air at the desired pressure in the receiver.
Usually this volume will exceed all downstream demand for a period of time. Therefore, once the receiver is filled, your air-driven equipment downstream from the compressor can - perhaps - cycle on and off a number of times without the compressor having to cut in every few seconds to maintain the downstream pressure set point.
It is important then to have a receiver size large enough that the compressor has ?rest? time, not just to help prolong compressor life, but due to some other benefits to having a large receiver as noted below...
Dec 10, 2009
Tank vs Air Flow Rate by: Sorlozer
yes. it has some relationship. The formula FAD = (P2-P1)/Pa * Q / t * Tin / Tout Where: P2 = Final Pressure after filling; P1 = Initial Pressure after bleeding; Pa = Atmospheric Pressure; Q = Storage volume in m3 which includes receiver, after cooler and delivery piping; t = time required to build pressure to P2 Tin = inlet Air Temperature; Tout = outlet Air Temperature; FAD = Free Air Delivery, cfm or m³/min Based on the formula, the higher the receiver capacity, the higher the FAD. However, that is not only the point to consider.
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Thanks "Sorlozer", we appreciate the info. Folks, this formula is from a visitor to this website, and as such, I have no way either of proving or disproving it's accuracy.