How Much PSI

[steamer]

Yes

I have seen this design many times. It has potential to be good ( or somewhat decent anyway) or bad...depending on who built it and how and with what. Ken's points are valid as I have threaded schedule pipe on my boat boiler in various locations and it hydro's just fine and I can assure you is well within ASME code stress levels and safety requirements...as I checked on my boat boiler anyway.

Schiezems. There are a good deal of books on the subject. I would suggest an investment in your education would be helpful and wise for all concerned. K.N. Harris's book is not bad, but I am sure there are others that are better. Learning the ins and outs of a model boiler is simpler if you start with a known design that performs well. Assembly issues will be minor and you'll have a known entity.

If you don't know what a hydrostatic test is ( a "hydro") It is a test used to safely test a pressure vessel prior to commissioning it with steam. It involves filling the boiler with water COMPLETELY. and then pressurizing it to some pressure above the maximum allowable working pressure ( 2X when new, and 1 1/2 X periodically there after....at least to my version of Section 1 sitting on the shelf).

If there is a failure of the vessel here, it will be a "plink" and a dribble of water. This is because water is not compressable and therefore doesn't store energy well...unlike superheated water and steam...which does with a vengeance!

These rules and procedures are there to protect you and the people around you from danger and have been created from first engineering principles and lots of experience.....ignore them I would NOT!

Welcome here and please ....be safe, and ask a lot of questions.....

Dave ( Steamer)

 

[Ken I]

Good point about the hydro test Dave.

If you don't have access to a suitable hand pump - fill the system with water and apply the test pressure with a grease gun (so you inject a little grease) via a good check valve (ball & spring) nipple.
For a small scale test this is fine - most grease guns can develop about 1000 psi.

Ken

 

[lennardhme]

Here in Oz, AALS [Australian Ass. of Live Steamers] sell a book of specs for copper boilers with all the info you will need to construct a safe boiler that can be approved for use in public places. Buying one would be a very good start for you, and youll end up with a safe boiler.
lennard

 

[ksouers]

Good point about the hydro test Dave.

If you don't have access to a suitable hand pump - fill the system with water and apply the test pressure with a grease gun (so you inject a little grease) via a good check valve (ball & spring) nipple.
For a small scale test this is fine - most grease guns can develop about 1000 psi.

Ken

Not to be contrary, Ken, just a warning: oil or grease in the boiler is not a good idea. It'll attach itself to the shell and carborize causing hot spots that will eventually burn through. Even a small amount will do it. Just need to make sure that the boiler gets a very thorough cleaning before it's maiden firing.

It'll be safer with a longish piece of tubing between the boiler and grease gun, just to make sure no grease can get to the boiler.

 

[Ken I]

Sorry - but that was supposed to be self evident - remove the grease after you have finished.

I like the tip of a longer pipe to avoid the problem in the first place.

You could also make up a little reservoir (a'la pipe bomb) to displace water from.

And just to pick up on Rake's warning at the top of the heading - make sure you conform to whatever local code is applicable.

Regards,
Ken