Pressure test / hydro test of portable air compressor - save yourself from exploded air tank...
Vložit
- čas přidán 25. 04. 2023
- Portable air compressors have been around for a while now. The horizontal tanks are vulnerable to corrosion along the length of the tank side-wall due to condensation water inside. Failure of a rusted-out tank can be catastrophic and lethal. It is possible to safely proof-test these tanks using high pressure water. In this video, I show how to configure a manifold setup for using the pressure washer to perform this test.
- Auta a dopravní prostředky
As a stationary engineer we performed many hydrostatic tests on boilers over the years. One detail not mentioned in your procedure is the temperature of the vessel/water. Both need to be at least 68F or 20C. The vessel's metal can become brittle at lower temps.
That's a very good point. The pressure washer has a 27kw electric heater for hot water power washing. The supply of water feeding the machine is from the domestic hot water tap in the workshop. Without the pressure wash heater turned on, the water is the temperature from the hot water tap. It's just a workshop without dishwashing or laundry so the hot water is only around 120°F for hand washing. For the test in the video, the pump was delivering this "bathwater" temperature water which is quite well over 68°F. Thankfully here in Alabama it's warmed up nicely already so it might not have been a problem even without the heated water. But this is a good point and I didn't consider it during the test.
Scary that that rusty old thing is probably safer than a brand new compressor from harbor freight or home depot. Good idea on the valves for testing
Made in USA to an actual pressure vessel standard. Definitely would be more worried about a thin walled HFT tank under similar conditions.
I saw that same video of the compressor aftermath when it blew out. Crazy the amount of energy stored. The guy in the video said it blew the windows out of the garage and the compressor hit the ceiling. I have my dad's old air compressor from when I was a kid. The tank had a pin hole in it when I powered it up years ago. No way am I going to mess around with that tank. I will be buying a new tank and probably go to a vertical tank when I do. What is scary is I didn't know the dangers of this when I powered up that compressor years ago. I'm fortunate the tank didn't rupture on me.
Yes the vertical tanks are much safer due to the failure point from rust-out being the low point at the center bottom head, around the drain fitting. That won't cause a split to form along the entire side of the tank.
I have done similar tests, and have yet to have one fail. I test every tank that is new to me. One thing I'd add is that if there is heavy rusting along the bottom, I no longer trust it. I have an 80 gallon one from 1961 that had an enormous amount of rust in the bottom, so I didn't use it. It sat outside for years after that, then I decided to test it for fun. It held 300 lbs, though it did have a very slight leak. Amazing how overbuilt the old American iron was.
I don't blame you for testing every tank new to you.
In my testing, two have failed. They just spray when a small tear opens, or multiple pinholes open up. Nothing too exciting. The two which failed were 4 or 5 years old flea market tool store tanks which were suspiciously light in weight.
Your commitment to safety is clear :) Same with how you make sure to ground the cabinet on all the fridges you work on, and ensure the overload is set up properly.
Thanks. Working in the industry where I do, safety is very important. Once it gets engrained into your way of thinking, you bring it home as well to the hobby workshop.
Very good information, all compressors need to be drained of water at the bottom, a few years ago I took a nice looking sixty gallon tank and made a bbq smoker out of it, when I cut it open for the door you could see the rust and deep pitting inside So just because a tank looks great outside doesn't mean it is good inside.
Exactly. My friend was a little disappointed when I would not allow the compressor to build pressure when we first got the motor running yesterday. I explained it the same way that you cannot tell by looking and his already had water in it which had been sitting a long time.
This is excellent information. I have a 35 year old compressor (i bought new) that appears new, externally, but I have wondered what it is like internally. I am going to duplicate this setup and test it. Thanks for the video.
Thanks for your comment!
Great video David! What a clever way to pressure test. I have been wanting to hydro test my old compressor's tank - now I know how. As always, great commentary and explanation! Thanks for posting!
Thanks!
That’s one sturdy craftsman even with that rust on it and water sitting in it for who knows how long.
Thanks, I too will be testing my tank. It looks great from the outside, but it's tough to know how much material is left in the bottom.
Very detailed and easy to understand explanation. Thanks for posting this video.
Very glad you found it helpful.
Excellent pressure test video
Thanks!
Nice video. You can add link to your video 'Popping an air tank with high-pressure water...' to the description if anyone want to see it
I need to do that!
I used to work at a place that manufactured refrigeration units for ice rinks and we made our own heat exchangers so we had our own testing rig, they used to do tank testing for other companies as well as pretty much any tank people would bring in.A small compressor tank like that was $50.00 back then.There are a number of places that will test a tank for you and it seems the newer cheap units let go more than the old ones, in any case they should all be tested on a fairly regular basis, I do mine every year.
Neat job you had there. Interesting about the ice rink refrigeration systems!
It's great that they offered this service to hydro test tanks for outside clients.
Yes the old tanks were build to ASME pressure vessel standards; whereas the imported ones are built to a standard but likely that standard doesn't require the same engineering margin as the ASME pressure vessel standards. Simply picking up an ASME tank versus a new import tank will speak volumes....
i believe i have the same compressor , but mine is a dayton brand . cast iron pump and flywheel . built to last .
I would imagine many of those failures resulted from a lack of maintenance i.e. draining the water from the tank once a day.
No doubt! That's one of the things nobody thinks about.
My question is, what if it failed the test and exploded with you standing near it?
Oh, you explained it would not explode since water is in it, right?
Hi Rickey. Considering it is "only" 250 PSI and the tank is full of water, the worst which would happen is I get sprayed with water. The water comes from the domestic hot water tap in the shop, which is just for hand washing so it is only warm. So I would have been sprayed with warm water if that happened. I closed off the pump supply and trapped the pressure in the tank before making the up-close inspection, as well. If it leaked it would have just been a small spurt.
I have had these fail before, and it's quite underwhelming. They just develop a small tear or pinholes in the bottom as the pressure is applied and water sprays out.
Does an air pressure gauge work with water?
Once the tank is filled to the top with water, could you use another air compressor to add air pressure for the test? Seems to me that this would also be safe ? (if you could get a high enough pressure).
I would hesitate to do that. My concern would be an unnoticed leak allowing more air than desired to get into the tank. Also it if ruptured with an air cushion over the water, that air would expand and greatly prolong the water discharge, maybe even causing the tank to be propelled.
@@davida1hiwaaynet What if as pressure source i will use long water filled hose which i will pressurize it with air? Also adding check valve and/or restriction near tested tank is a good idea? Check valve on will stop water/air flow if tank ruptures, restriction will just slow down water near tank inlet.