old compressor explosion risk?

[zardoz]

After seeing an old compressor explode in a youtube vid i started to wonder about my own old compressor. I know they should have bleed valves regularly tapped to get rid of moisture in the air condensed to water. But even so it will still eventually rust on the inside, and with the preponderance of cheap cylinders there days, who knows how many are in our garages waiting to blow.

Anyone know of a way of checking them?

 

[brightspark]

yes tip it over and tap all along the bottom with a ball pein hammer if it easily dents its weak they all go rusty in side .that films a load of ****** no way would that open up like that .ive seen leaky rusty tanks and they would pinhole well before they would open up or split i did a test a year ago on a one gallon oil can and it took 50 psi before the crimped base blew out i showed the picture of it on one of my posts on here with it

 

[Robotstar5]

Don't know if there's a DIY method, but we had the works ones inspected using ultrasonic/ultrasound? the insurance guy would put some gel onto the receiver and run the sensor over it and it gave a thickness reading.

 

[optima21]

I had a compressor that rusted out from the inside after being about 15 years old, it was only noticeable as it lost pressure over time, you couldnt even hear the air leaking when it was switched off, certainly not catastrophic failure.

thinking about it, its also possible that the solenoid which switches the motor off had stuck on, which would have then just carried on increasing the pressure, and if there wasn't a safety valve fitted (the compressor of mine that rusted out didnt have one) then untimately it would have ruptured.

I think for model steam boiler testing, they hydraulically test them with water to twice the normal working pressure, and if it doesnt leak its fine.

 

[brightspark]

.......

I think for model steam boiler testing, they hydraulically test them with water to twice the normal working pressure, and if it doesnt leak its fine.

steam boilers are hydraulically tested at twice pressure when first built from new then subsequently tested at 1and a half times pressure thereafter

 

[lshigham]

Don't know if there's a DIY method, but we had the works ones inspected using ultrasonic/ultrasound? the insurance guy would put some gel onto the receiver and run the sensor over it and it gave a thickness reading.

Our Zurich assessor just has a peek inside with a torch every year, means I get a fun day of removing bungs!

 

[Rig Pig]

Ours are UT inspected annually and condemned long before they are any danger, I keep meaning to pop the end cap of mine for a peep inside to see what it's like.

 

[rtbcomp]

At what sort of age do they get condemned?

 

[MattF]

Only time I've personally come across photo's of spectacular results like that, someone has usually run the compressor tank to above it's standard pressure. Suppose it could happen though under normal use. Freak accidents wouldn't be freak accidents if they were normal.

 

[brightspark]

a pipe bomb filled with sodium chlorate and weedkiller dont even open up that flat

 

[brightspark]

heres the post http://www.mig-welding.co.uk/forum/threads/testing-a-pressure-vessel-oil-can.25381/

 

[Rig Pig]

The age varies I would guess 6 to 8 years, but they live in a very corrosive environment, a home garage would be much kinder to them.

 

[doubleboost]

You just get a leak no way can it explode like that

 

[rtbcomp]

This may give a clue, from here http://ncsp.tamu.edu/reports/WorkCover/Alerts.htm

How can an air receiver tank explode?
During operation, deposits of lubricating oil tend to build up in the line supplying compressed air from the compressor cylinder to the air receiver. As the diameter of the supply line decreases, the already high temperature of the compressed air rises further to a point where it is possible for the contaminant to ignite.

Sparks are then carried into the air receiver where oil from the compressor, which is often present as a mixture with air in the air receiver, burns explosively. As the pressure relief valve is not designed for such an event, rupture of the air receiver vessel is likely to occur. In other air compressor accidents, static electricity sparks have also been identified as a source of fires and explosions.

 

[doubleboost]

This may give a clue, from here http://ncsp.tamu.edu/reports/WorkCover/Alerts.htm

How can an air receiver tank explode?
During operation, deposits of lubricating oil tend to build up in the line supplying compressed air from the compressor cylinder to the air receiver. As the diameter of the supply line decreases, the already high temperature of the compressed air rises further to a point where it is possible for the contaminant to ignite.

Sparks are then carried into the air receiver where oil from the compressor, which is often present as a mixture with air in the air receiver, burns explosively. As the pressure relief valve is not designed for such an event, rupture of the air receiver vessel is likely to occur. In other air compressor accidents, static electricity sparks have also been identified as a source of fires and explosions.

Good reply

 

[rtbcomp]

It's something that never occurred to me, quite frightening really.

 

[lshigham]

At what sort of age do they get condemned?

Not known one fail yet and some of the recievers have been used since the mid 80's, the air is all refrigerant dried and they all have auto drains which probably contributes to their lifespan.

 

[Wallace]

That tank doesn't even look particularly badly corroded inside but the weld has been positioned at the bottom where water would sit. Is there a HAZ on the weld shown @2:48 showing a possible repair?

 

[MrFluffy]

I just put mine inside a dedicated block small outbuilding and dont go in there when its got power to it or has pressure in the tanks and have a switch in the workshop that energises power to it. I did this because it has a welded repair already where a previous owner screwed up the drain bolt and another bung had to be welded in to fix the mess but that was about 9 years and about a zillion pressure cycles ago now. Side benefit, I dont go deaf from the compressor running and now I've got hard airline running all over my workshops so no trailing hoses or cables.

 

[AndyStobbs]

Surely every receiver under the sun has a HAZ on it, from bosses being welded on, the seam of the cylinder and the end seams.