Compressor requirements....

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I tried asking on my local area community, since... they're really all pretty smart people.But that turned out to be a big fail, lol.I'm more or less trying to figure this out.Using conversions from http://www.pnconline.com/conversion.htm#Scubic foot per hour = 0.124676 x gallon per minutecubic foot (US) = 7.481 x gallon This means there are 7.481 cubic feet, per gallon.Correct?The item I'm powering, is https://www.mythermadyne.com/thc/en/...AddButton=trueArcAir K-3Flow Rate: 21 cfm (0.60m3/min)Pressure: 80 psi (5.6kg/cm2)There's the requirements.Nooowww what kind of compressor am I looking at?Specs are fine, exact models not needed.I'm assuming if I get a 175psi 80 gallon tank, the run time will be under one minute if the pump is not running, using the numbers above.What are the min specs of a compressor you guys would typically get to power such an item?I was trying to stay under $1000 (but looks like I'll be going quite a bit higher, which is ok), but with these requirements, that does not really seem possible. Seems like 16-17CFM @ 90psi compressors can be had for ~$800, but then when you jump up to 20+CFM the price jumps above $1500 as well.Ideally I would like to be able to use the K-3, without having the pump running and drawing power.But that doesn't seem very likely in a sub 150-200 gallon compressor.Edit:I'm also limited to 240v Single Phase, 50 amps max draw.Last edited by Hass; 10-23-2009 at 09:46 PM.
Reply:your looking at a fairly decent two stage compressor to reach those numbers they can be had in the $1000. range and will run at the power draw or less that you have available. If that's all the available juice you have you might look into a gas powered compressor more money but it would allow you to use both pieces of equipment at the same time.
Reply:Is this for a mobile or shop setup?If this is for a shop and you want to do that much air arcing, I would get an industrial rotary compressor that runs continuously.  They usually only put out 100-125 psi, but have huge flow, minimum 25 to 200 cfm, depending on size.  They are not cheap new, but I see them for sale used alot more lately.  They're usually powered with 3-phase motors.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Originally Posted by DesertRider33Is this for a mobile or shop setup?If this is for a shop and you want to do that much air arcing, I would get an industrial rotary compressor that runs continuously.  They usually only put out 100-125 psi, but have huge flow, minimum 25 to 200 cfm, depending on size.  They are not cheap new, but I see them for sale used alot more lately.  They're usually powered with 3-phase motors.
Reply:LArge piston compressors come in two varieties usually. Twin cylinder single stage, and two stage compressors.Twin cylinder single stage units are basicly 2 pumps attached to the same motor. Each one compresses intake air and sends it to the tank. Usually these are rated at a max of about 125psi, but at greater CFM's than 2 stage units of the same HP. They make large amounts of lower pressure air for high volume tools.Two stage units compress the same air twice. The air gets compressed by the 1st piston then goes into the 2nd piston where it is compresses again. These usually go up to 175psi, but because the still have only one intake they move fewer CFM's at a give pressure. These are usefull for tools that need high psi air, but don't need as much volume.Most small gas units are twin cylinder single stage compressors. As suggested screw machines are the way to go for volume. If you don't need this much everyday but only occasionally, you might look at renting a unit when needed. A standard tow behind jackhammer compressor ( they are screw machines) usually makes about 165-185+ CFM at about 125 psi. My local rental center rents one for $36 for 2 hrs or $98/ day..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:cubic foot per hour = 0.124676 x gallon per minutecubic foot (US) = 7.481 x gallonThis means there are 7.481 cubic feet, per gallon.Correct?
Reply:Originally Posted by Oldiron2I didn't try to follow your math, but know that 1 gallon = 231 cubic inches, so the highlighted statement can't be right.
Reply:WOW Hass  you could run a air compressor that has that kind of CFM output on a air / ar gouger with 50 amps @ 240 volts. But it would take a lot more input than that to run a gouger!Your friend, Doggie
Reply:Hmm? 1 Cubic foot = 1728 Inches. (12"x12"x12")So if there's 231 Cubic inches per gallon, that's 1728 / 231 = 7.48So using your own statement, it verifies the above highlighted statement?
Reply:Originally Posted by Oldiron2No, you got the terms inverted; it's 7.48 gallons per cubic foot!Solve for 'X':'X' gallons  = 1 cubic foot  ; substituting gives'X' (231cu in. /gal.) (1 gallon)  =  (1728cu in. / cubic ft.) ( 1 cubic ft.)  'X'  = 1728 / 231 = 7.48  .
Reply:Originally Posted by HassSo a 60 gallon compressor would equal to 448.8 Cubic feet?
Reply:Originally Posted by HassSo a 60 gallon compressor would equal to 448.8 Cubic feet?
Reply:Originally Posted by BoostinjdmNO.  8.02 cubic feet at atmospheric pressure.
Reply:wait nevermind, i failed on that one.Didn't realize I mistyped my first post -.-Thought he was disagreeing with me, when he was actually agreeing with me...because I had fudged it up.Was using this page...http://www.truetex.com/aircompressors.htmand in my confused state of crunching numbers and ****, i fudged it