HoleeCrapp. Air compressor explosion

The company I work for was tasked with inspecting the damage caused by an explosion at an EAF furnace at Timken Steel. Water cooled furnace and water was the issue. Sad to say, three workers were splattered with molten steel and unfortunately one of them passed.

Nothing to do with this post other than an explosion

 

Yup, water and molten steel is no joke...makes a steam explosion and blows molten steel everywhere...its a nasty cleanup, at the very least.

 

So, the video in the original post is interesting. Around 2:45 we get a better view inside the tank. There is at least a handful of loose rust still present in receiver tank on the left side.

There is a follow up video where the owner says the compressor is 10 years old at the time of failure. He drained it regularly and the relief valve worked. The follow up video speculates the failure started at the seam weld that was at the bottom of the tank. I would agree with that. The owner says he had no indication of a weak tank, but I believe he did....he rewelded the factory bung the drain valve is threaded into. In the video part of the bung is factory paint and part is rusty weld.

I think the tank failed along the seam but original failure was where the wheel brace was welded to the tank body. Then the crack propagated along the HAZ of the weld. Then butterflied as the air put a twisting motion on the newly freed side of the tank. The fact some of the welds were rewelded leads me to believe the welds were of poor quality, poor penetration, porous, bad heat management..... And possibly crappy steel.

I've seen some pretty bad Chinese steel in the last 10 years. I've seen some pictures where some bad welds were hidden under caulk that was applied to look like weld beads before painting.

And it all looks good with a shiney coat of paint

 

I worked besides induction furnaces that were water cooled. It is intimidating. We always inspected the crucibles after every melt.
Last thing anyone wanted is that failing and causing a major explosion. Fortunately no major mishaps besides mold blowouts on the occasion.
Everytime I fill my scba tank I always get nervous. You see what 125/150 psi does, at 4500 psi they probably will be scraping me off what 2x4's they can find.
I usually start it, check it and leave the room and re-check it every few minutes until it is close to full. I probably should buy some choke cables for my lines..

 

I was in my 20's when I got my scba compressor. We were really rural back then an blew up everything that we could find. Had a hole in the ground to put stuff in. When things get past 2-3k psi things get interesting quick.

 

Go look at some of the cheap compressors being sold now. In 10-20 years hearing about ruptures will be common.

 

Just looked at mine! It's rarely used.

 

Nice catch....and I wonder how many pig tanks at work and the farm are out of date. I do know we have some that have been on the farm for 40 years.

 

Ours says Oct 2014

 

I wish I'd kept the pic, but about 15 years ago i had a pic of a locomotive aux reservior that blew. Those are puffed up with 140#, are 18" in diameter, and 6' or 7' long. They are placed horizontally.
When it blew, the steel deck was well bend up. I'd hate to have been anywhere near that when it went, and we walk by those hundreds of times a day.
I'd also hate to be anywhere near the main mover when a catastropic failure occurs. Ive seen pics of 10" pistons having exited a locomotive & gone through someones roof, and lodged in their interior wall.
Lotsa energy there!

 

Drained my compressor after seeing this thread.

 

This was brought to me today to see what could be done with it.
I said scrap it!!
He left it, has nice wheels on it though.

 

I inherited a portable compressor and the drain was plugged and it had a bunch of water sloshing inside. I don't use it anymore and it has been replaced with an old westinghouse, which turns out to have a bad pressure switch which sometimes does not turn off on time and it ran up to at least 275 psi. I walked into the shop and saw 275 on the gauge and almost crapped my pants. (It was not running) I cracked the drain and walked away. The tank is rated to 300 or 325 psi, but it still scared me real bad. It was like stepping on a mine and wondering if it would go off. I had forgotten the tank rating and I never dreamed that compressor and little motor could ever make that much pressure.

 

Years ago I went to help at a friend's family farm.
I was asked to go to the shop and start the compressor. I got there and I found a old refrigeration compressor on a few hundred gallon propane tank.
No pressure switch, no gauge, no safety valve..... nothing.
I went and asked about it and was told to reset the circuit breaker and when it's full the breaker will trip.
He had no clue what pressure it stops at just that it's been that way for years!

 

Those compressors will make 4-500 psi or more. I would not want to be anywhere near that if it blew. Talk about a bomb....

 

I turned it on but didn't stick around!!
As a kid open refrigeration compressors were quite plentiful. The ones with eccentrics instead of crankshafts could well exceed 1000 psi. With a old gas bottle as a reciever we blew up so much stuff!!