100 LB Propane Tank as Main Displacer "Open Source"

[RogerAS]

Link

All,

On another forum, the walking beam Stirling forum, I have started a thread about using the tall 100 LB propane tank as the main displacer body in a simple Stirling engine. This is going to be an "Open Source" effort where any and all are welcomed and encouraged to participate as long as the documentation is offered free to the public. I am shooting for a 100 watt engine, which I feel is a goal well within reach. I actually hope millions of folks build these in their back yards!

Thanks all.

RS

[cognos]

I like it. I'm there. Don't know what I can contribute, but I'd love to build one, just to tinker with.

[Dail R H]

Got a link, I googled it n couldn't find it. Goes back to my earlier comment about using the older principles n new approaches / technology.yes they would be large n cumbersome , and ineffecient, but probably thourly reliable for those with a steady fuel supply.

[Carlb]

Got a link

Just click on the word link in blue in his post

carl

[RogerAS]

All,

My first steps to build this prototype have begun. I have selected what seems to be an average 100 LB tank. I have taken measurements and am in the process of developing a scaled drawing in 3 views. A lot of my time is being diverted in math problems/conversions rather than design. Since I'm attempting to build something anyone can make (walking beam engine) these drawings and measurements are rather important. When I finish these drawings (and parts lists) I will post them on the net and beg for input.

I can export files in AutoCAD format if others want to make revisions/improvements and have machine shop (CNC) access.

I expect to have first drafts of these drawings by next weekend (late). It may take a day or two to generate a parts list to match the drawings.

RS

[LowGear]

Hi,

You can copy (Ctrl-A ..... Ctrl-C) to Paint and saveas to JPG and then post them just about anywhere. 

Casey

[RogerAS]

Hi,

You can copy (Ctrl-A ..... Ctrl-C) to Paint and saveas to JPG and then post them just about anywhere. 

Casey

LowGear,

Heh, I have top end drawing software, and several years in graphic/web design, but thanks for the tips. I was just making it clear that if there are those out there with CNC capabilities and AutoCAD support I can supply those files on request in addition to the web ready files.

RS

[Crumpite]

This sounds like a very interesting project.
Last summer I went to an old engine show, and they had an old Ericsson style pumping engine going.
They are quite small, about four feet tall and about two feet square.
I've heard that they were rated at about 1/8 hp, and it sat there for days pumping drinking water for the folks.
They only needed to throw in a couple of small pieces of firewood every half hour or so.

Pretty amazing.

It didn't do much work, but it did it constantly with very little attention.
I could see one pumping water for irrigation or to water your livestock.

There isn't too much to wear out on them either.

I'd guess that something with a 100lb tank as a displacer could do some real work !

Please keep us posted !
Crumpite

[LowGear]

Sorry!  I didn't mean to step on anyone's toes but not everyone has top end software but everyone, even Macs I think, can open JPG files to see what the heck you're talking about.  I taught introductory computer classes for a couple of decades and it always sat me back in my seat as to how ignorant some of the "Hot Shots" were as to simple Windows 3.1 keyboard shortcuts.  I had a tutor stop by a couple of years ago to help me put a irrigation plan together and he was pretty surprised how compliant Auto-cad 2007LT was to the simpler OS commands.

Anyway:  I do have a collection of propane tanks and a supply of WVO that's too nasty for me to try do anything with except maybe play with my neighbors Turk (SP?) burner.  I have heard of Stirling engines but never these "do it yourself" units.  I think I might be up to some of the quality assurance standards that a few of the units shown on the link.  Any guesstimate as to how many horsepower one of the 100 gallon cannons would produce?

Casey

[mike90045]

Don't propane tanks have a big weld seam in them that would have to be ground down for a piston ?

[Crumpite]

Don't propane tanks have a big weld seam in them that would have to be ground down for a piston ?

Well, first it's going to be used as a displacer, not a piston, so the clearances are much more relaxed.
Second, I think a little quality time with a hand grinder would make it smooth enough pretty quickly.
You usually need an air gap around the displacer anyways (depending upon it design.)
Hope I didn't misunderstand your question.

What I'm wondering about is what is the displacer cylinder is going to be made out of.
That could make or break the project.

Crumpite

[LowGear]

Do you have a link to the design you're most enthused about for this propane tank concept?

Casey

[RogerAS]

Do you have a link to the design you're most enthused about for this propane tank concept?

Casey

Well, LowGear, the whole idea is my brain fart so far. I rally am hoping to inspire others to take up the idea and run with it. That's where the open source part comes in. I am NOT interested in making any money off this idea. I just think there is a need and my 100 watt goal doesn't seem too out of reach.

If one follows the link in the OP to the site where Stirlings are featured the "walking beam" design can be seen. I plan on using this design basis and will expand on things as I go.

As for the displacer I'm thinking of a thin aluminum sheeting with spokes for internal support. It needs to be tough and light, and may take several tries to get right.



More to come.

RS