Pressure Test of Vessel - Home Visit

[WvW]

Ok chaps, apologies for the delay - first i had to wait for some stillsons to turn up so i could get the expansion port open, then i thought id better get a endoscope which can take photos, rather than trying to take photos of a screen. That being said, some of the photos are not that sharp, but i wonder if thats more me than the camera (I was trying to hold a light in there as well). Anyway, my first impressions (noting i am not in any way qualified) is that the corrosion is minimal, and the welds look clean and uncorroded, so its a goer. Anybody think otherwise?

These first ones are all looking down, at the bottom of the vessel, and the best i could of the weld. The drain port is just visible (with a slightly more orange rust circle around it).

These two are looking up towards the top.

 

[WvW]

And these are looking straight at the lower weld, and where it meets the weld along the vertical axis of the vessel (The halo seems to appear when the light is insufficient, and isnt part of the vessel):

 

[brightspark]

I have a borescope camera and wouldn't bother even looking

 

[Brad93]

Nowt wrong with that

 

[WvW]

I know what you mean - I wasnt going to look, but I scared myself when I thought about it giving way, particularly when I didn't know for certain it had been well looked after. And it's right next to the neighbors shed.

Overkill probably, but I feel better for looking.

 

[RWD3M]

As Brad says, I don't see too much wrong with that.

 

[brightspark]

when they do leak its only rust pinholes and u hear a slight hiss and a bit of water on the floor so its no big deal and isn't going to burst on you

 

[Farside]

when they do leak its only rust pinholes and u hear a slight hiss and a bit of water on the floor so its no big deal and isn't going to burst on you

This fella probably thought so, too.

I imagine there was some brown on the ground.

 

[Keith 66]

I had a big old broomwade compressor when i had the boat workshop up the farm. I had a look inside the tank & cleaned a load of rusty sludge out of it. Date on the tank was 1946 & it was made from heavy 1/2"steel plate.
The Romac compressor in my workshop now has two tanks under it that are 6" dia with 3/4" wall thickness, i dont worry about that one as there is quite a bit of corrosion redundancy there.
The burst compressor tank in the photo above probably started life at 3mm thick. No room for corrosion there.

 

[Seadog]

It does look paper thin. My 1969 I-R is at least 5/16", probably 3/8" and has been hydraulically tested to 240psi.

 

[Munkul]

There's a good reason why newer receivers made to SPVD standard have to be visually inspected every 12 months. They're horribly cheap and mass produced. I'd wager that propane bottles are made to a higher standard.

Stupid idea. Should have stuck to making vessels to proper codes like PD 5500.

Anyway that guy in the video had advance warning... Looks like he had to weld up some corrosion leaks around the drain.

 

[rtcosic]

Anyway that guy in the video had advance warning... Looks like he had to weld up some corrosion leaks around the drain.

That probably saved him from a worse outcome. Usually, the domed ends are the weakest part of a pressure vessel and if it fails there it becomes an unguided missile. Failure along the seam is less common and the vessel tends not to fly quite so far.

I'm sure @Parm has access to hundreds of photographs, videos and reports of pressure vessel failures. Most are probably due to external fire, but some will be simple mechanical failure or overpressure.

 

[Munkul]

That probably saved him from a worse outcome. Usually, the domed ends are the weakest part of a pressure vessel and if it fails there it becomes an unguided missile. Failure along the seam is less common and the vessel tends not to fly quite so far.

I'm sure @Parm has access to hundreds of photographs, videos and reports of pressure vessel failures. Most are probably due to external fire, but some will be simple mechanical failure or overpressure.

I was taught that generally cylindrical vessels fail along the longitudinal axis - just like that one in the video.
It stands to reason too, as generally, hoop stress is much higher than longitudinal stress.

Flat ends are a different matter of course.

 

[rtcosic]

I was taught that generally cylindrical vessels fail along the longitudinal axis - just like that one in the video.
It stands to reason too, as generally, hoop stress is much higher than longitudinal stress.

Flat ends are a different matter of course.

Quite correct, but the dished ends I am most familiar with are torispherical heads which are usually the weakest link. I was extrapolating from industrial-scale vessels down to mass-produced small scale stuff and my assumptions may indeed be wrong.

Sorry about that.

 

[Brad93]

The thing is proper receivers aren’t even that expensive.

We've got a cheap clarke receiver up at the minute.

Next time I want to put a galvanised vertical receiver outside under the lean to and get the compressor out there too, be a bit quieter in the workshop.

 

[Farside]

Next time I want to put a galvanised vertical receiver outside under the lean to and get the compressor out there too, be a bit quieter in the workshop.

Now there's an idea.
I'd thought of putting mine outside, but the prospect of losing it to thieves is too high.
However, having the whirly bits inside (I don't mind the noise of a belt drive unit) and the tank outside in its own wee shed - that would work, and nobody's going to nick the tank.

 

[RWD3M]

The thing is proper receivers aren’t even that expensive.

We've got a cheap clarke receiver up at the minute.

Next time I want to put a galvanised vertical receiver outside under the lean to and get the compressor out there too, be a bit quieter in the workshop.

It's always surprised me why receivers aren't galvanised It just seems such a sensible precaution.

The 270ltr tank on my Clarke will be getting galvanised when I strip it down for a good overhaul in a year or two.

 

[Seadog]

The Bambi silent compressors have receivers that are painted internally.