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Air compressor tank max pressure

kunkernator

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So, i recently came across a 60 gallon air tank. it is in 100% perfect condition, manufactured in 2009. The cylinder was just bad.

This is what I am planning on doing to it, but I want the internet's assistance on how safe it is. I currently have a 30 gallon compressor which shuts off at 150psi. I want to plumb this new 60 gallon tank in tandem to the 30 gallon compressor; so that the 30 gallon pump pressurises both tanks. I have no concern with the pump/motor because they are both rated at 100% duty cycle. My concern is with this new tank. The stock shutoff for this 60 gallon tank is at 125psi, the pressure relief valve is set for 150psi, and the tank is rated for MAWP (maximum allowable working pressure) at 150psi. Would it be alright to pressurise the tank to 150psi? From what I understand, it would be ok, given the working pressure maximum rating is 150psi. I would replace the pressure relief valve with one that is rated at 160psi.

So, to the point; is it safe to operate a MAWP@150psi tank at 150psi consistently? I say yes, what do you say?

EDIT: I might add that the MAWP is rated 150psi@400 degrees F......
 
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Rico.

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If the tank is rated to 150psi then it is safe to 150psi, regardless what the original
pressure switch attached to it was set at. As for having an escape valve set for 160psi,
that just seems perfectly logical to me... In the unlikely event of your pressure switch failing
the tank will only be at 7% over maximum pressure before you discover the problem.

I have always wondered what the industry standard for safe margins of air compressor
tanks was anyway. i.e... If a tank is rated for 150psi at what pressure does it truly become
dangerous... Obviously what ever that number is, it would get lower with each passing year,
but I am curious what a new 150psi rated tank is actually "safe" to.
 

thedark3rd

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You will be fine, the pressure relief valve, and check valve should be the same as the tank with the working compressor. All your ratings are based on the motor/pump (CFM,max PSI, Cutoff, and duty cycle). The new tank should have a label welded to it with all its specifications. If not, go to the hardware store, pick up a plug and inlet coupler you can connect to the new tank, along with a pressure guage, and try pressurizing the tank. Go in steps. Whatever you do, the new tank has to match the specs of the working compressor.
 
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kunkernator

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All of the specs i provided were off of the welded plate to the tank. I just want to make sure that if i pressurize the tank to 150psi that it is not going to rupture.
 

zkling

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What are the other specs on the tank out of curosity? Who made it?

One thing I would be concerned about is the long on time of your compressor. You are increasing the capacity to 3x of what it was designed to fill. You may end up putting too much strain (mostly heat) into the pump and motor. Although I see you say the pump and motor have a 100% duty cycle.

What compressor is it? Is it a single stage or dual stage? 150psi is a bit of a goofy cut off point.

One thing... I WOULD NOT replace the pressure relief valve, that valve was speced to that tank.
 
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TAMPAGT07

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What are the other specs on the tank out of curosity? Who made it?

One thing I would be concerned about is the long on time of your compressor. You are increasing the capacity to 3x of what it was designed to fill. You may end up putting too much strain (mostly heat) into the pump and motor.

What compressor is it? Is it a single stage or dual stage? 150psi is a bit of a goofy cut off point.

One thing... I WOULD NOT replace the pressure relief valve, that valve was speced to that tank.

This is what I was thinking....If your running an industrial compressor, this would be fine, but for a small garage, it might be overkill...
 
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theknurl

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look the safety factor up its an ASME spec

ASME diving tanks rated at 5,000 PSI have a 4 to 1 safety factor

:thumbup:


:beer:
 

zkling

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and boy are they fun when they blow.

A friend of mine's dad built or tried to build a compressor out of an old water heater when he was in his teens. :headshake said it took out the garage door. Every time the talk of pressurized tanks comes up, he reminds us of his adventure.
 

Jim Johnstone

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Forgive my green..ness, but I assume this means a 5000psi diving tank has been
tested to 20,000psi without it blowing up.

Not tested necessarily, but designed to burst at 20000 psi. Just out of curiosity what diving tanks do you have that are rated to 5000 psi working pressure? My highest are 3500.

Sent from my SGH-I727R using Tapatalk 2
 
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kunkernator

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What are the other specs on the tank out of curosity? Who made it?

One thing I would be concerned about is the long on time of your compressor. You are increasing the capacity to 3x of what it was designed to fill. You may end up putting too much strain (mostly heat) into the pump and motor. Although I see you say the pump and motor have a 100% duty cycle.

What compressor is it? Is it a single stage or dual stage? 150psi is a bit of a goofy cut off point.

One thing... I WOULD NOT replace the pressure relief valve, that valve was speced to that tank.

The current compressor i have is the HF 29 gallon. It is one badass pump, and i have had it run constantly for 30 mins, no prob. The 60 gallon i have ordered a rebuild kit and already started wiring up 240v. When done, i will have two pumps in the system (taking more strain off the 29 gal). The 60 gallon pump will cut off at 125psi (what it was designed for, and currently set to), and the 29 gallon pump with pressurize the system the remaining 25psi.

I proposed this idea to a friend/teacher today, he specialized in hydraulics and pneumatic brakes (with over 30 years field experience, plus 10 in the military), and he told me there should be no problem with the set up. The only thing he suggested was to not change the 60 gallon pump's cutoff up, because it may strain the pump as it was not designed for such use. That is how i came to the idea described above.

I think i should be all set. Last question being; what gauge wire should i use to run 240v? I need about 20 feet, i was thinking 8 gauge solid strand.
 
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