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From: "Tom Dasto *"
To: jdotson@belmont.astro.nwu.edu (Jessie Dotson)
Date: Tue, 30 Jan 1996 17:07:49 EST
Subject: do's & don'ts
Cc: sean@irastro.gsfc.nasa.gov (Sean Casey), Scc1960@aol.com,
jdotson@belmont.astro.nwu.edu (Jessie Dotson), Scc1960@aol.com
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Jessie,
Here is the list you wanted. If I think of anything else, I'll
update it.
SPARO DOwar (& Don'twar) Ideas
In the following tables are listed specific DO's & DON'T's relating to the
design of the SPARO dewar.
Disclaimer: Items listed below may or may not be meaningful in a Helium 3 system.
DO
1 Utilize vapor cooling
2 Attach shields to vent tube at locations closer to the reservoir than predicted
3 Use thick vent tube attachment plates
4 Align bolt patterns between all "shells"
5 Use metal o-rings (smallest diameter possible)
6 Design o-ring glands for stock rubber o-rings (useful during initial phases)
7 Use as many bolts as can fit in the pattern when sealing components with metal
8 Place o-rings on the "up" side of all components
9 Design with Pro/E
10 Use flathead screws between shields
11 Attach end-support rings to shields to maintain circularity during assembly
12 Build a stable work/assembly stand
13 Try to design an adjustable structure (thermal and mechanical tweaking)
14 Design a shorter/fatter dewar over a longer/skinnier dewar (more top plate real-estate)
DON'T
1 Use small tolerances for frequently assembled components
2 Leave less than 0.1" material in a threaded blind hole
3 Use doublers/rivets on shields
4 Underestimate friction in mechanisms
5 Design without Pro/E
P. S. I was really stretching for some of these!
Tom