[dinger]

This story was in the Fresno Bee today. The net version is shortened a bit.http://www.fresnobee.com/updates/story/1136067.html try this again:
http://www.fresnobee.com/updates/story/1136067.html
The air compressor tank had been repaired at this shop, they were testing it when it blew up. One man killed immediately.

[oldred]

That reads like so many I have seen in safety bulletins from years past, while fortunately it is not a common occurrence it does happen far more than most people realize. Of the one's I have read about and the two I witnessed first-hand most were related to attempting a repair which should of course NEVER, EVER be done! Both of the tank explosions I looked at were caused by rust/metal fatigue but repairs accounted for the largest number of the one's I read about. Sometimes these explosions involved injury and sometimes a fatality and I can only guess at how many close calls went unreported since unless an injury or fatality was involved it was not included in those bulletins. I remember one in particular where a large tank of about 200 gals at a sawmill blew the end out and the main portion of the tank body was found nearly 1/4 of a mile away!

[metalmeltr]

My dad has a 60 gallon cambell hasfeld 2 stage compressor that is probly 20+ years old and it works great. We had to change the pressure switch and magnetic starter a couple years ago but other than that it is all good. There are a few leaks in our air lines so it will bleed down overnight, but i usally forget to turn it off so it stays pressurized. If bleeding don the comressor is bad is using auto drains also bad. As far as tank explosions are concerned I have taken pop bottles both2 liter and smaller ones and drilled a hallf in hole in the cap put a valve stem in the bottle the fits snuly in the neck and the cap holds it in and presurize it as high as I can get it abuot 120 psi and poke a hole in it with a nail in the end of the stick andthe blast is like a shotgun and it ecoes in the suronding woods, the first time i did it i heldit and just poked the hole but now I stand back and whack it with the stick with a nail in it since my hand was numb after doing that. any way when i do ths the bottles can fly 20' and that is not with much pressure

[oldred]

If that compressor is bleeding down to zero (or nearly so) every night you should find out why and stop it, probably a simple shut-off valve at the tank will do it. Having to refill a compressor tank from zero every day puts a tremendous amount of unnecessary wear on the pump because of the long run time and heat build-up, occasionally dropping the tank to near zero will not not hurt anything but it adds up fast. If this happens, for example, 250 days out of a year and takes 7 minutes to refill from empty that is about 29 hours of wasted hard run time per year not to mention the wasted power. The bigger problem though is the fact that the tank has to expand and contract through each of these cycles which will greatly shorten it's service life and as old as yours is it likely will not have a lot of time left anyway so you need to go easy on it. Most people don't realize that a tank undergoes expansion and contraction during discharge/recharge but it does, not much during the normal discharge/recharge cycle but all the way down to zero and than back up to pressure causes a lot of expansion/contraction which will eventually lead to tank failure due to metal fatigue. Obviously letting the tank drain to zero is a REALLY bad idea and you really need to address this problem as soon as possible, especially considering how old that compressor is.

[dinger]

Originally Posted by oldred

If that compressor is bleeding down to zero (or nearly so) every night you should find out why and stop it, probably a simple shut-off valve at the tank will do it.

What Red says, a valve would be a good way to stop this drain down. Another thought, if you have a few leaking hoses, these hoses probably aren't far from total failure. Blow a hose, have the compressor run continuously until someone shuts it down can't be a good thing. I shut mine down EVERY time I quit for the day. Thevalve would be good insurance for the forgetful.
Dan

[66GMC]

I've got a buddy that only runs his compressor when he wants to use it.
Having to wait for that ... what a pain!

I have a ball-valve shut-off on mine, so it stays at 125 PSI all the time. It runs very seldomly (if ever), and air is available any time I want it.

Think of air as "kinetic energy", and spend the time to find and repair any line leaks that you can. Doing so will save you money, time, and aggravation.

Spend the extra money on good quality couplers, plugs, teflon tape and hoses ... they'll pay for themselves over time.

[oldred]

I just came across this little incident on another forum and since this old thread was revived recently I thought some of you might find it interesting.


The fella that was telling what happened said his uncle had a small compressor that was about 20 years old and they had forgotten to unplug it and the tank let go on the thing during the night. He described the tank as "opening up like a banana peel" and going through the metal siding of their small garage where it left a hole big enough for a man to crawl through. They found the tank about fifty feet away from the building and the pump about 100 feet away, he said they could not even find the motor! He ended the story by saying he has become a big fan of hydo testing after seeing that!

While tank ruptures are not exactly an everyday occurrence they do happen and sometimes it can get real serious. Injuries and even fatalities are sometimes the result of these failures and property damage besides the compressor itself is likely in the event of a failure so it is a very good idea to treat these things with respect and DON'T TAKE CHANCES!