Blown up compressor tank

[Aerogt01]

All this online engineering and I don't see that nobody has mentioned hoop stress. Amazing.

Hoop stress plus longitudinal stress at a weld plus rust and possibly cycles (if the max psi stress times a Kt is above the endurance limit)? That can absolutely happen if there is an overpressure.

 

[Dick in Wisconsin]

The mechanic was hurrying a side job, so he could get it out before the owner showed up the next day.

Things were doing OK at 2AM when the mechanic finally got his side job done and went home. Neglecting to shut down the compressor. About 4 AM the compressor kicked in. The screwdriver shifted and the compressor kept kicking in. And the blowoff couldn't kick in. And when the motor was about to melt from driving against 300+ psi in the 20 yo tank, the fuses weren't there to blow. And the tank did. It made an amazing mess.

Did the mechanic lose his job?

What about putting two or three blow off valves on the unit? Is that feasible?

Or two limit switches in series?

 

[TractorJeff]

I've posted it before, 200 gallons, riveted steel. Laid the steel out flat and flew it across the room! One end cap went through the ceiling and roof to be never found. Wood splintered out of the wall landing 100 feet out. A Farmer running a Haybine about 1/2 mile away heard the BOOM!
Cause?
Over Pressure!
Compressors old and new will fail at some point, can we be so paranoid that we bury them in concrete lined bunkers? No, I think out of the millions out there and the number that fail per year. You would have better chances of winning the Lottery!

 

[kaymccampbell]

Did the mechanic lose his job?

What about putting two or three blow off valves on the unit? Is that feasible?

Or two limit switches in series?

Lord knows. It was like 50 years ago. I think everyone lost their job as the garage was torn down and never reopened to my knowledge.

Yes and yes. My old120 gallon Wayne had two popoffs sticking out of it. And I imagine there are compressors with multiple pressure switches. Easiest thing is to test your popoff monthly. And replace when suspect. Which I did on the old one and still do on my much more recent vintage 60 gallon vertical.

 

[Dragster Racer]

All this online engineering and I don't see that nobody has mentioned hoop stress. Amazing.

Hoop stress plus longitudinal stress at a weld plus rust and possibly cycles (if the max psi stress times a Kt is above the endurance limit)? That can absolutely happen if there is an overpressure.

Cycles make no real difference if there is enough of an overpressure. Once can do it. But it is a hard one to prove given what we see. And there is no recordable evidence proving the overpressure. And what is the condition of the relief valve? I would be tempted to deadhead the pump and see what it will go to pressure wise. And certainly temperature can make a difference.

 

[Cyberbear]

Yes, the pictures look scary and are enough to make anyone apprehensive. But before we all jump to conclusions, more info is required. Without knowing all the details, no factual answer can be established as to what caused the explosion, only that it did. I've seen other examples of tank rupture explosions caused by over pressure, and that is what this resembles. I always test the safety devices when I acquire a new unit and once a year there after.

 

[lakeroadster]

Yes, the pictures look scary and are enough to make anyone apprehensive. But before we all jump to conclusions, more info is required. Without knowing all the details, no factual answer can be established as to what caused the explosion, only that it did. I've seen other examples of tank rupture explosions caused by over pressure, and that is what this resembles. I always test the safety devices when I acquire a new unit and once a year there after.

Visually you determine it is from over pressure? Explain... in detail.

After all you just wrote "before we all jump to conclusions".

In my experience in an over-pressure situation on a tank with dished heads (that are not hemispherical) the head ends up with what looks like a "dent" in the knuckle radius, a pronounced dent. It is a result of the head trying to go hemispherical, and pulling the metal.

I don't see that.

 

[Yv.]

Hope I never see that happen, really scary.

 

[dkmc]

I have 2 saftey valves on each of my 2 tanks, and I run 110PSI max.
I don't understand why people run 150 or 175PSI, it's asking for trouble.

 

[rlitman]

I have 2 saftey valves on each of my 2 tanks, and I run 110PSI max.
I don't understand why people run 150 or 175PSI, it's asking for trouble.

Because they have thicker walled tanks.
Do you understand why 2000 PSI is not fully filled in an oxygen cylinder?

 

[dkmc]

Because they have thicker walled tanks.
Do you understand why 2000 PSI is not fully filled in an oxygen cylinder?

Your comment is senseless....
There's no good reason to run those high pressures.
Most air tools, including impact guns are rated at 90PSI.
The higher the pressure, the more stress there is on all
components.

 

[rlitman]

Your comment is senseless....
There's no good reason to run those high pressures.
Most air tools, including impact guns are rated at 90PSI.
The higher the pressure, the more stress there is on all
components.

Your comment is senseless. There are plenty of reasons to store gases at all sorts of pressures. There is no good reason to store gas at a pressure higher than that a tank is rated for; sure. But tanks come in all sorts of pressure ratings.

 

[dkmc]

I give up

 

[sublimate]

Your comment is senseless....
There's no good reason to run those high pressures.
Most air tools, including impact guns are rated at 90PSI.
The higher the pressure, the more stress there is on all
components.

Storage volume is the reason.
You have 4 times the useful air stored at 170psi vs 110psi.

 

[WhiffySpark]

I give up

110 psi at the tank is way less at your tool

 

[dkmc]

Storage volume is the reason.
You have 4 times the useful air stored at 170psi vs 110psi.

Not a good reason. Get a bigger tank and run lower pressure.
Easier on all the components, makes less heat, less water in
the tank and lines.

 

[CNGsaves]

^ ^ ^ You STILL do NOT get it. In demanding environment (auto body shop with air sanders running all day, etc) having just 110psi in lines would be ****. With only 20psi over what the end device is drawing down pressure (ie 90psi), the pressure in airline system could dip down to low pressure bogging down the tool.

It's very reason there are TWO-STAGE and even 3 and 4-stage compressors. Demanding environments NEED that higher pressure to get things done. Simple.

Safety warning that you are leaning towards is good advice for inadequate compressor tanks or airline systems to NOT try to operate beyond their INTENDED Working Pressures. Pressure vessels (tanks) have both Max pressure and working pressures listed on the tag.

 

[sublimate]

Not a good reason. Get a bigger tank and run lower pressure.
Easier on all the components, makes less heat, less water in
the tank and lines.

LOL. Maybe not a good reason to someone who doesn't do any real work.
Why not run with no tank at all if you're so scared of a little air?
I've got 2 x 80gal tanks. 8 tanks would be stupid for so many reasons.

Do you drive down the highway at 30mph? It's a lot easier on you car, wastes less gas, safer if you get in an accident?

 

[rlitman]

Do you drive down the highway at 30mph? It's a lot easier on you car, wastes less gas, safer if you get in an accident?

No, the speed limit should be 25 MPH. It's much safer around pedestrians.

 

[roguegts]

I give up

Wait... so you want to buy 4x's as many tanks and compressors, so you can run them at a lower pressure? When they are perfectly safe to operate at 170-200psi? And no, it doesn't create any more water if you work off equal volume. Heat yes, but this isn't the intake charge on a racecar, what difference does that make? If you're so concerned run a big screw compressors and never look back.

 

[G_P]

^ ^ ^ You STILL do NOT get it. In demanding environment (auto body shop with air sanders running all day, etc) having just 110psi in lines would be ****. With only 20psi over what the end device is drawing down pressure (ie 90psi), the pressure in airline system could dip down to low pressure bogging down the tool.

It's very reason there are TWO-STAGE and even 3 and 4-stage compressors. Demanding environments NEED that higher pressure to get things done. Simple.

Safety warning that you are leaning towards is good advice for inadequate compressor tanks or airline systems to NOT try to operate beyond their INTENDED Working Pressures. Pressure vessels (tanks) have both Max pressure and working pressures listed on the tag.

Exactly. When I worked in a propeller shop, we had a massive 3phase compressor and an equally large refrigerated air dryer. IIRC it had 20hp motor, a 3 stage pump that looked like a radial airplane engine, and made well over 200psi. We needed it because we had multiple media blasters, air sanders, air grinders, blowguns for clearing dust, and multiple paint booths. We used massive amounts of air and if we ran the compressor at even 150psi, it would never be able to keep up with the demand when we were busy and everything was being used at once.
Turning off the compressor at night was strictly enforced. Outside the compressor room was a large red light that would be on whenever the compressor was powered up so it was very hard to forget to turn it off when leaving for the night.

 

[dkmc]

It's very reason there are TWO-STAGE and even 3 and 4-stage compressors.

Better check on those 4 stage units.....might be your imagination.
Nobody needs 150-200 psi in their garage at home, which is what this thread is about.

 

[RustFarmer]

I don't understand why people run 150 or 175PSI

These pressures are necessary to inflate load range G and H truck tires. While your compressor's 110 psi may be at or slightly above what you want in the tire,airing up from 80 to 105 with 110 psi air will take a loooong time.

 

[Busted_Knuckles]

These pressures are necessary to inflate load range G and H truck tires. While your compressor's 110 psi may be at or slightly above what you want in the tire,airing up from 80 to 105 with 110 psi air will take a loooong time.

I can think of several tools that dont function well or at all, at 110 and down.

Ive got mine set at 150/175. While I dont hope to blow it up, running under 125 is frustrating.

 

[CNGsaves]

Better check on those 4 stage units.....might be your imagination.
Nobody needs 150-200 psi in their garage at home, which is what this thread is about.

Well . . . I DO have 4 stage compressor . . . . it's for Natural Gas / CNG !!

It's pressure cutoff is 3,600 psi so it DOES quite a bit of work to get the job done filling up CNG tank in vehicle. Fuelmaker is designed for this very purpose and tank in vehicle is rated from safety pressures over 5K psi so I don't worry a bit.

Now, I'm not Darwin candidate and try to pump 3,600 psi into an inadequate 3K psi tank or heaven forbid something less.

When systems are properly designed and maintained, they really DO work !!

 

[dkmc]

These pressures are necessary to inflate load range G and H truck tires. While your compressor's 110 psi may be at or slightly above what you want in the tire,airing up from 80 to 105 with 110 psi air will take a loooong time.

There's some useful information.
I do the Machine Shop thing, so I don't need to fill large tires.
But I have topped off forklift tires at 100PSI, and it doesn't seem to take
much time. Maybe an extra minute or 2

Lookie here......this company makes 3 AND 4 stage compressors.
http://lmcompressor.com/products_3_and_4_stage/
For those of you that want to run 550PSI to 1530PSI....

 

[rlitman]

Better check on those 4 stage units.....might be your imagination.
Nobody needs 150-200 psi in their garage at home, which is what this thread is about.

Here's a video of a 5-stage compressor.

It looks pretty clear, and not like a "dream scene" flashback, so I'm going to go out on a limb and say it is probably not imaginary.

I fill my bicycle tires to 130 PSI. Bicycle fork shocks usually get well over 200 PSI.

A compressor that tops out at 110 PSI, is cycling on at say 80 or 90 PSI.
But the time that reaches my plasma cutter, that's not enough pressure for it to run, so it would cycle off at the bottom of every compressor cycle.
I need a constant minimum of 130 PSI in the tank to deliver 120 PSI in the lines downstream of my regulator. Which means that my pressure at a minimum would have to top out around 150 PSI.

You're using the same argument as my state's A-hole governor who thinks that nobody needs more than 7 bullets in a firearm. Funny how his body guards have more than that. Anyway, nobody needs to be told what they "need" from someone who obviously doesn't understand their needs.

 

[srr]

I have an 80 gallon 2 stage compressor in my garage it's a CH made in 1977 with a tank rated at 200 PSI working pressure. Works perfect. I used to have it set to go off @ 160 PSI. I also have a 50' hose reel at each end of the 30' garage with 1" copper pipe connecting the two with a regulator on each one. Nothing I do out runs this compressor and I even use it to blow down the driveway after weed whacking. I have since turned it down to go off @ 120 PSI and on @ 90 PSI. Since I fixed all the air leaks (Hoses went bad on both reels) I'm lucky if it kicks on twice if if I'm out there all day in the garage working. I turned the PSI down to see if it made a difference in the power bill. It did. I don't get too much water in the tank and when I drain it, it's never rusty. I wouldn't go any lower PSI settings than this because then it will short cycle which is harder on the compressor than a longer run cycle.

 

[Busted_Knuckles]

Better check on those 4 stage units.....might be your imagination.
Nobody needs 150-200 psi in their garage at home, which is what this thread is about.

Ive got a bristol 4 stage 10hp in my shop. They do exist. Not saying I have a good use for it, but have it none the less.

 

[srr]

Some of the older tanks were made from materials that had very poor qualities at cold temperatures and were prone to brittle fractures, such as SA-216 and SA-515. That means if it does fail it can be catastrophic. Most of these materials have been eliminated.

Always look for an ASME stamp and data plate on any tank you purchase. If it doesn't have one, don't buy it.

http://www.inspection-for-industry.com/pressure-vessel-certification.html

Agreed!

 

[lakeroadster]

Better check on those 4 stage units.....might be your imagination.
Nobody needs 150-200 psi in their garage at home, which is what this thread is about.

Your still not getting it.. it's about storage space.

P1*V1 = P2*V2

100 PSI * 20 Gallon Tank = 200 PSI * 10 Gallon Tank

You only need half the tank size at the higher pressure....

As a fella who designed pressure vessels for a living, before I retired, I can assure you the safety factor on a 100 psi ASME tank is exactly the same as a 200 psi ASME tank.

Neither is "safer" than the other.

 

[rlitman]

As a fella who designed pressure vessels for a living, before I retired, I can assure you the safety factor on a 100 psi ASME tank is exactly the same as a 200 psi ASME tank.

Yes, BUT, most hobbyist compressors do not come with ASME rated tanks.
You start to see ASME ratings in the larger tanks (everything 80 gallon and up), but it's pretty uncommon in the smaller tanks (I haven't seen an ASME plate on anything imported for example).

So, knowing that, I would actually say that the people here who own dual stage compressors with ASME tanks that are running 175 PSI, probably have a larger margin of safety than the people here who have single stage non-ASME tanks running at 100 PSI. That stands exactly counter to dkmc's argument.

 

[WhiffySpark]

What is your pressure at the end of your hose when you only run 110 in the tank? I would think you'd have a ******** in your hand pretty much.

I know my impact ***** *** with less than 90 at the end of hose

 

[BDT/NWMN]

175psi is a normal setting on many commercial grade compressors... If this pressure was senseless, why would compressor manufacturers build such units?? Some of Us do the same work at home that is done in commercial shops; and can justify these larger, higher pressure units..

Some people will state that they do not understand why some of Us need this pressure..
I certainly agree with them on this:::they do not understand!!!:

Agree?

 

[lakeroadster]

Yes, BUT, most hobbyist compressors do not come with ASME rated tanks.

File that under Caveat Emptor... Buyer Beware

Don't buy a "pressure vessel" that doesn't have an ASME stamped tank. Problem solved.

Look for one of these types of cloverleafs:

New ASME stamp:


-----------------------
Previous ASME stamp:


-----------------------
And the data stamping is very similar to this:

 

[roguegts]

Better check on those 4 stage units.....might be your imagination.
Nobody needs 150-200 psi in their garage at home, which is what this thread is about.

Well that's a damn presumptuous statement to make isn't it? How do you know what I require in my garage?

 

[03fan]

This is why I have my air compressor wired up to an on/off switch with a pilot light. I only turn the air compressor on when I need it and make sure it's off before I leave.

 

[1redTA]

where did the no shrapnel guy go?

 

[ms fowler]

Agreed!

I had one of them fail. 80 gallon tank of unknown age or condition. Yes, I now realize I was stupid ( and lucky). I rebuilt the compressor and never gave the internal condition of the tank a thought. I located it outside my home garage/shop in a protected area under a 2nd floor deck. One endplate blew off at about 110-115 PSI. It destroyed several shelving units and parts books, and tool boxes. My neighbor, who worked at Aberdeen Proving Ground came out looking for human remains. he said it sounded like a grenade. VERY lucky no personal injury.

I now have a healthy respect for air tanks AND the people who can weld pressure vessels.

 

[gasman23]

Your still not getting it.. it's about storage space.

P1*V1 = P2*V2

100 PSI * 20 Gallon Tank = 200 PSI * 10 Gallon Tank

You only need half the tank size at the higher pressure....

I worked at a plant where they had a high pressure compressor and air tank.
Pressure in the 500 gallon tank is 500 psi.
Downstream of the tank is a pressure reducer, pressure in the 2" lines is only 120psi
The "smaller" tank saved a lot of valuable space.