displacer gasket insulating material?

Discussion on Stirling or "hot air" engines (all types)
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spinningmagnets
Posts: 27
Joined: Sat Aug 02, 2008 7:34 pm
Location: NW Kansas, USA

displacer gasket insulating material?

Post by spinningmagnets » Mon Aug 04, 2008 2:56 pm

I read a post that indicated when a running Gamma had its displacer cylinder made thinner by machining, and it reduced the heat flowing over to the cooler side. After this, the hot side was hotter, and the cool side stayed cooler, leading to a more powerful engine.

(I also plan on using the flywheel spokes as a fan to cool the cool end, with air flowing from the tip towards the center).

I'd like to put a thin ring of insulating material between the hot and cool ends of a gamma displacer cylinder.

Any material suggestions?

speedless
Posts: 36
Joined: Fri Apr 06, 2007 1:58 pm

Post by speedless » Wed Aug 06, 2008 1:13 pm

Hi
Look at this:
http://uk.rs-online.com/web/search/sear ... 4294954657
Very expensive!
Jan

spinningmagnets
Posts: 27
Joined: Sat Aug 02, 2008 7:34 pm
Location: NW Kansas, USA

Post by spinningmagnets » Thu Aug 07, 2008 2:17 pm

Thanks, Jan.

I will keep this in mind. I know the space shuttle has insulating tiles that are replaced every trip, so the old ones are sold to tourists very cheap, but they would be awkward to cut and use.

I may just put an engine together, and then add the insulating gasket later.

spinningmagnets
Posts: 27
Joined: Sat Aug 02, 2008 7:34 pm
Location: NW Kansas, USA

Post by spinningmagnets » Sat Aug 09, 2008 9:25 pm

I know asbestos is unfashionable, but if you don't breathe in the tiny fibers, it works well.

Mica is starting to look good. I'm assuming I'll be making the displacer cylinder out of aluminum, and the displacer itself out of thin stainless steel.

I just need something to thermally isolate the hot end from the cool end.

The search continues...

ABEC1971
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Joined: Sat Sep 20, 2008 7:36 am
Location: Illinois, USA

Post by ABEC1971 » Tue Oct 07, 2008 7:49 pm

I'm very new to the hobby, but to me, it would seem that you'd want the displacer to be a thermal insulator. I'm in the process of designing a gamma type engine and I was planning of making the displacer from plastic (UHMW or similar) with only thin metal caps on either end. Am I correct in my thinking?

Cartech
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Location: Northern Nevada

Post by Cartech » Wed Oct 08, 2008 12:44 pm

I see no problem with it as long as you stay within it's temperature limits.

RichD
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Insulator

Post by RichD » Wed Nov 26, 2008 4:42 am

You could use the kitchen counter top underlayment sheet material. I believe it is 1/2" thick and sort of like cement with a fiber mesh inside. You can saw it and drill it using regular tools.
Rich DeMartile

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