Re: Welding a small pressure test vessel...

Steve B wrote:

"Pete C." <aux3.DOH.4@xxxxxxxx> wrote in message
news:464397F7.67671F2E@xxxxxxxxxxx
I'm not a certified welder in any way, shape or form. Mostly self taught
though I did take an evening class at a tech school once. I do 95% TIG
on steel with my Syncrowave 250.

I have a project that I need to do which is a small pressure test
vessel. Max operating pressure is 150 PSI, air only, at least two safety
valves. Rough design is about a 12" length of 8" dia .5" wall steel
pipe, fixed welded on base plate and a removable top cap.

Figure the top cap should have say six bolts to secure it, most likely
hand knob style on a loosen and swing to the side out of slot in cap
type arrangement for convenience. The top cap will also need to have a
view port, presumably 1" lexan well reinforced with a couple steel cross
bars.

Recommendations on how to do this safely? Am I crazy to attempt it? It's
fairly low pressure and small enough to be overbuilt without excessive
cost. Were I able to do this as a hydrostatic chamber I'd be perfectly
comfortable, but as an air type chamber the potential catastrophic
failure mode makes me nervous.

Thanks,

Pete C.

I would suggest that you keep the area of the Lexan small. Look at other
plastics and compare strengths. As the other poster suggested, doing
allthreads with two caps would allow you to sandwich the plastic in there as
one layer, and you could make the hole in the top cap smaller in diameter
making the surface area of Lexan (whatever) smaller, thus a little beefier
in area/thickness ratio.

Interesting project.

Keep us posted.

Steve

The window does not need to be large, just enough to keep an eye on the
unit under test. The real testing is watching the pressure gauge after
shutting off the air supply to look for a drop in pressure indicating
air is leaking into the "sealed" device under test.

The tie rod design is not ideal from an operational standpoint as it
would require full removal of the hand knobs to remove the lid vs.
loosening and swinging to the side like the fasteners used on many trash
pump housings.

Pete C.
.

Relevant Pages

  • Re: Welding a small pressure test vessel...
    ... I have a project that I need to do which is a small pressure test ... Rough design is about a 12" length of 8" dia .5" wall steel ... Figure the top cap should have say six bolts to secure it, ... Easier yes, but way too expensive, like 5X what it should cost to build ...
    (sci.engr.joining.welding)
  • Re: Welding a small pressure test vessel...
    ... I have a project that I need to do which is a small pressure test ... Max operating pressure is 150 PSI, air only, at least two safety ... Rough design is about a 12" length of 8" dia .5" wall steel ... Were I able to do this as a hydrostatic chamber I'd be perfectly ...
    (sci.engr.joining.welding)
  • Re: Welding a small pressure test vessel...
    ... I have a project that I need to do which is a small pressure test ... Max operating pressure is 150 PSI, air only, at least two safety ... Figure the top cap should have say six bolts to secure it, ... is no catastrophic failure mode potential. ...
    (sci.engr.joining.welding)
  • Re: Welding a small pressure test vessel...
    ... I have a project that I need to do which is a small pressure test ... Rough design is about a 12" length of 8" dia .5" wall steel ... Figure the top cap should have say six bolts to secure it, ... Plunger has been removed from a HF $10 grease gun. ...
    (sci.engr.joining.welding)
  • Re: Welding a small pressure test vessel...
    ... I have a project that I need to do which is a small pressure test ... Max operating pressure is 150 PSI, air only, at least two safety ... Rough design is about a 12" length of 8" dia .5" wall steel ... Were I able to do this as a hydrostatic chamber I'd be perfectly ...
    (sci.engr.joining.welding)