Compressors - drain every day or leave pressured?

[Tom Veatch]

And I doubt that you will hear of one caused by rust through. Failure of a pressure relief valve along with simultaneous failure of a pressure shut off valve could cause overpressurization to the point of catastrophic failure in a tank in good condition. Rust through will weaken a tank wall to the point that pinhole leaks will develop at the weakest points. Those pinholes could grow due to the escaping airflow, but in doing so, would act as a pressure relief valve reducing the tank pressure. Catastrophic, shrapnel producing tank failure due to rust through is a very low probability occurrence.

My opinion, unsupported by any indepth analysis, is that being brained by a meteorite is about as likely as being injured by a rust through failure of a shop compressor tank.

And no, I'm not saying rust through failures don't occur and people have been hit by meteorites. I'm sure someone's second cousin thrice removed has a neighbor who knew someone who'd heard of about a pressure tank exploding due to rust through..

[Puckdropper]

Tom Veatch wrote in news: [e-mail]:

Water would tend to collect in the bottom of the tank first, and that's where the rust would occur, right? So by the time the bottom of the tank has rusted out, the sides and top of the tank would still be in good shape. Should the right conditions occur, I think it more likely a compressor tank act as a rocket and not a bomb.

Puckdropper

[Leon]

NO! Like a glass of ice water the water would collect on all cooler surfaces, basically every square inch of the interior surface of the tank. Compared to the very hot compressed air going into the tank, the tank is quite cool in contrast. Then as the moisture condensed more, it would run down to the bottom and collect, but the whole tank is going to be wet.

So by the time the bottom of the tank

No, see above.

Should the right conditions occur, I think it more likely a

No, Pin holes will develope all over the surface. I had an old 80 gallon compressor, that I inherited, develope pin holes near the center of the sides of the tankfirst, none were at the bottom.

The above is true if the compressor is use regularily. If you store it for years on end with water in side and bring up the pressure the bottom may fall out then.

[Puckdropper]

"Leon" wrote in news:PI6dnegbKaDxYIzXnZ2dnUVZ [e-mail]:

Ah, I see there's more to the story than I had originally thought. Would a light-use (that doesn't cycle often) compressor tend to act like the stored tank?

Puckdropper

[Leon]

I was referring 10-20+ years with water stored inside. If it simply sat the condensation would eventually settle to the bottom. Then it may fail in a particular area. If it sat long enough that there was considerable rust around the perimeter of the stored water and you then added pressure there might be a more dramatic failure, if the large rust area suddenly gave way. Typically however the weakest point will be a pin point leak that could grow in size over time

[Jack Stein]

Does that mean you think it will do something different? If so, what and what makes you think so? I've never heard of one going boom but even then, I would think it would be less than spectacular.

Well, what do you think makes tanks that are constantly wet last for 30

- 50 years and more?

I've been around stuff, and doing stuff that OSHA would have cardiac arrest over for my entire life. So far, even though I may have been lucky a time or two, I'm still alive and well, no serious damage. I feel somewhat comfortable with my judgment so far. As for insurablity, I've never needed a sure thing to survive, and wouldn't want to live that way anyway. When I got my first mower that the mower deck shut off when you went in reverse, I immediately disconnected the dammed thing... I like living on the "edge" and don't need no stinking insurance company, or government, to force me to their levels of safety. I've been using table saws without a guard for close to 50 years, and have no plan on sticking one on now. They look downright dangerous to me...

Well, I can dance with a sufficiently loose definition of the word dance, and sufficiently large enough consumption of alcohol, and there is a fine line between being able to "dance" and being unable to walk to the dance floor...

[Jay Giuliani]

I would be more worried about the lost capacity in the tank if it not drained regularly.

I have never seen a tank go south and that includes reservoirs on ships that were 40 years old.

I lean toward small pumps but like to mount reservoirs in the system for pressure stability.

I have two small compressors selected for their noise level and kept in clean areas in the basement.

They have automatic float type drains but small tanks.

Since water does not compress like air, I would be more worried about loss of air stowage.

I don't think I have ever had a pump outlast a tank.

Piping is a different issue especially with all the oil free pump ends that are out there nowadays.