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Re: Hello I am new, and I need advice for presssure vessel

Posted: Mon Oct 18, 2010 1:02 am
by Junkie
Hi,
you didn't say, but from your dimensions and descriptions, can I assume that this a LTD engine, perhaps running off a cup of water ?
--so first question is: is it better to have center of pressure vessel of some heat insulating material or all vesel of one material (steel).
My pressure vessel is of 3 parts top and botom is top and bottom of steel paint can (height of each part is 20mm) and center is sewage pipe (height 40mm) I think that material of pipe is PE plastic, ID of all parts is 110mm.
Sounds fine to me.
--second question is: is it ok rate of pressure vessel diametre vs height D=11/H=8, and what is recomended height and diameter of displacer.
Displacer is D=95mm ; H=40mm I cant get better fit with steel wool
I'm not sure about these ratios, sorry.
--third.. I have three displacers two was in operation one not yet. first cardboard with loot of wood glue (seems like perfect airtight), second styrofoam , and third steel wool
so I have problems with steel wool, my steel wool is very fluffy and it scratch on pressure chamber becouse of that i have big gap betwen vessel and displacer, how you solve that problem?
Displacer is relatively low for its diameter D/H=10/4 anybody make that type of displacer of steel wool?
Styrofoam should work best in my opinion. I use polystyrene in my LTD Stirling engine without problems.

I think you'll have trouble making a displacer for an LTD using wire wool. It works great in my coke can Stirling engines but the diameter is very small. I think wire
wool will be too weak for this kind of engine.
--forth.. what is better type of sealing element for displacer rod, pipe or one middle chamber with two holes (upper hole atmosphere lower hole pressure vessel).
I get better fit with holes for middle chamber.
I just use one hole for the displacer bushing and one for the diaphragm. Keeping friction to a minimum is critical to get these engines working.

--Admit that I am boring :D I thinking about idea to extend PE pipe and turn upside down upper part of paint can, than i get pool for water on top but then I loosing side cooling area. OK or NOT?
No problem :)
perhaps is good to mention that I am mechanical engineer and I understand very good theory but I do not have experience.
this prototype have no power (when I moving up and down styrofoam displacer, rubber membrane have no force) I dot know where is problem.
I would like to get low and wide engine.
There must be a leak if there's no force on the diaphragm. What heat source are you using ? In my LTD the diaphragm will move about 10mm if you move the displacer rod up and down.

Re: Hello I am new, and I need advice for presssure vessel

Posted: Sat Oct 23, 2010 10:42 am
by jimlarsen
I have a paint can stirling engine on my website. You might find it helpful. Http://StirlingBuilder.com.

Paint cans will work but they are not ideal. The material is so thin that they flex with the pressure changes.

My website has some links to some video on YouTube that shows the engine running.