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Replies: 12
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Oculus Spirit [93645]
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Engineering assistance needed.
Jun 30, 2019, 3:19 PM
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I am designing a vacuum press system using a vortex. I'm attempting to evaluate my compressor to see if it meets standards required by the vortex system I want to use.
So far I've determined that my compressor kicks in/on when tank pressure drops to 80 psi and kicks out/off when it reaches 120 psi 68 seconds later. My calculations produce a 4.2 cf/min. The requirements of the vortex system is " 1.8 CFM at 80 psi or 2.2 CFM at 90 psi requirement for compressor."
My calculations do not reveal the psi requirements. I only have the CFM number. How do I evaluate the psi requirements.
And ask me if I've check the lint trap or unplug it and plug it back up again.
OK, go ahead, I deserve it, you guys owe me a few.
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CU Medallion [50635]
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Re: Engineering assistance needed.
Jun 30, 2019, 3:24 PM
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Oculus Spirit [93645]
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Wouldn't it have been better to recommend a new air filter?
Jun 30, 2019, 3:39 PM
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Don't take this like I'm thinking I'm smarter than anyone else here. You have no idea how much I struggled to remember my Betty Crocker physics courses at Clemson.
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CU Medallion [50635]
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clearly the answer involves some Pi and a parabola or 2***
Jun 30, 2019, 4:10 PM
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All-TigerNet [11626]
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You're neglecting the tank volume.
Jun 30, 2019, 4:53 PM
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Your compressor can raise X Volume from 80 to 120 psi in 68 seconds. Work the volume to get your answer. Unless you have a very small tank, it sounds like your compressor will work.
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Oculus Spirit [93645]
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No, tank volume was used to calculate early in the process.
Jun 30, 2019, 8:01 PM
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The tank volume (13 gal) divided by the 7.48 gal/cuft took gals out of the equation using the factor's units method.
Tank volume is used only to do the math because tank volume is the experimental size used for the calculations. Any sized tank could be used I believe.
I'm thinking I agree with you about my compressor being sufficient but without knowing the rate (what I say 4.2 cfm?) without knowing how or why they specified a xxxcfm at yyypsi standard. Maybe it's a simple as the average between the 80 and 120 psi test. I suppose it would have been much different if the regulator on my compressor wasn't set up to kick in/on until the tank drained to 40 psi and didn't cut off until 120.
I'm not happy risking the money it takes to build a vortex system if it means there's a risk my compressor isn't sufficient. If I had a shop or garage I'd already own a two stage, 3 phase compressor and have a wall full of pneumatic tools. I love air.
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All-In [30825]
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Re: Engineering assistance needed.
Jun 30, 2019, 6:27 PM
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Heisman Winner [135792]
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Doesn’t one suck and the other one blow?
Jun 30, 2019, 9:26 PM
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You blow up your tires with a compressor and suck up your stuff with a vacuum
Sounds like you’re at cross purposes here
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Oculus Spirit [93645]
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That sound like a good Friday night.***
Jul 1, 2019, 6:39 AM
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Oculus Spirit [85229]
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Oculus Spirit [93645]
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You heard me!
Jul 1, 2019, 7:42 AM
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CU Medallion [64837]
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Re: Engineering assistance needed.
Jul 1, 2019, 11:15 AM
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Well if the lowest pressure you are seeing is 80psi, and you are calculating 4.2cfm, then surely your compressor meets the requirements of 1.8cfm at 80psi AND 2.2cfm at 90psi.
It seems odd to me that the requirement has a lower flow at the lower pressure and a higher flow at the higher pressure. That seems bass ackwards.
Compressors in that size range are cheap as crap. Buy one 2x as big as you think you need and just go with that one.... OR buy two that are sized to carry the load and call one an installed spare. If you end up needing both, they you can just turn the other one on.
It's checkers, not chess.
source: I just spec'd out a 8,000 CFM compressed air plant at 120psi. Three 350HP fixed speed compressors (two running and 1 spare, running at 100%) and 2 400HP variable speed compressors (1 running as a trim compressor and 1 spare). All Atlas Copco.
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Oculus Spirit [93645]
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Re: Engineering assistance needed.
Jul 1, 2019, 5:22 PM
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Yeah, I thought the requirements were a little bassackward too. I reckon they meant it the other way. 1.8cf @ 90 psi and...
I was uncertain my logic was sound but I'm not buying another compressor. Mind produced enough. Vacuum can mess up a piece of wood trim that comes in automobiles. They are made typically from thin aluminum bases with a thin wood on each side to balance the moisture expansion of the wood, a thin piece of wood for a base then the super thin veneer which is finished. The odd shapes make it really tough to support the trim without having it bent or wrinkle in a vacuum press.
I'm using a vac bag system for a containment and because there's no practical way to duplicate the contour of the face.
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Replies: 12
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