MetalworkingFun Forum

I have one that was designed for a fresh air inlet to a welding helmet, its capable of either cooling or heating the air.

Arvid,
I have seen the Otto site - he says it should be a plastic tube or at least insulated if metal. The one I made used Aluminium tube and I have to say didn't work as well as I thought it would.
I hadn't seen the 'instructables' thanks

Seems from the Otto site there are some sizes (or ratio of sizes) that are important.

DaveH

Jack,
Got any pics or information?

DaveH

(03-29-2013, 02:29 PM)DaveH Wrote: [ -> ]Seems from the Otto site there are some sizes (or ratio of sizes) that are important.

DaveH

There seems to be some theoretical work out there for dimensions but getting thru them would seem like more of a career opportunity than something to do as a hobby ...

http://www.me.berkeley.edu/~gtdevera/not...extube.pdf

http://www.me.berkeley.edu/~gtdevera/not...extube.pdf

And then there is this which at least has dimensions on it ... http://www.visi.com/~darus/hilsch/.

Thanks Arvid,
I'll need to sit and read them
I made mine about 1994 I didn't have quite so much access to information then. So mine was more guess work than any thing else. Like Tom said it "eats" the air.
Now there are commercial ones about so, me being me I thought I might copy one of those - I'm not proud

These commercial ones seem to do the job - I think

DaveH

Here's mine. It's the Vortex name, made by 3M and just as loud as I remember. It does work well though, 23ºF on one end and 95ºF on the other. I might try using it again with some snap lock coolant hose. That might quiet it down a bit, but it's still an air hog.

Tom

I used to have a Snap-On "choke tester" until someone "borrowed" it out of my tool box when I wasn't around/looking.

It worked really well but as Tom said, they are very CFM hungry. I have a Snap-On air operated vacuum pump (venturi type) that is an air hog also.

Maybe this will help a bit?

[attachment=4850]

Here's some interesting reading on the subject, and some plans (sort of).

http://www.rexresearch.com/ranque/ranque.htm

Thanks guys for all your help.
I was hoping there would be something that would run on 50 psi and use .5 SCFM - seems not to be at the moment.

I still may look at trying to make a 'small' one and see what happens.
Although I don't think it will work that well (not after reading all the info), because of the lower energy input. I'm sure it will blow hot one end and cold the other but the difference may not be enough to make it useful.
Thanks for all your inputs

DaveH