Stainless steel pipe chamber

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Rich Feldman
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Re: Stainless steel pipe chamber

Post by Rich Feldman » Thu Jun 29, 2017 7:09 pm

You can clean up sawed pipe ends with an angle grinder. If the pipe is cut to length at a metals store, they might do it with a bandsaw that could make a pretty straight cut.

It doesn't take much wall thickness to make a strong enough cylinder. The ends are another matter, if you are talking about flat material and pipe diameter over 6 inches.

Look up a fusor thread by David Kunkle (?) a couple of years ago, as he was planning an 18 or 20 inch cylindrical chamber, and talking about strength of materials.
After running the numbers for flat disk thickness requirement, he went with ready-to-weld convex "tank heads", same wall thickness as the cylinder.
For somewhat smaller cylinders, have you considered hemispherical heads?
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ian_krase
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Re: Stainless steel pipe chamber

Post by ian_krase » Thu Jun 29, 2017 11:09 pm

Yeah depending on circumstances a sphere with nonstructural "ends" might be easier.

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Rich Feldman
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Re: Stainless steel pipe chamber

Post by Rich Feldman » Fri Jun 30, 2017 11:43 pm

Oops, just saw that the early posts talk about a flat (cyclotron-like) chamber. If the cylindrical section's length is to be much less than it radius, and dished or hemispherical heads are out...

1. For end plate thickness requirements, try searching for "plate deflection calculator" or "plate deflection formula". Here's one: http://www.roymech.co.uk/Useful_Tables/ ... lates.html which has, right at the top, "circular plate, uniform load, edges simply supported" and "edges clamped". Note the factors of t cubed and r to the fourth.
plate2.PNG
plate2.PNG (18.86 KiB) Viewed 210 times
2. How about making the cylindrical section out of a flat strip (aka thin rectangular bar), bent into a circle, instead of starting with a tube? Then the surfaces where it joins the end plates would be nice to begin with. You would have more choices of material and thickness, and infinite flexibility on the diameter. Cutting would be minimal if cylinder length matches the width of a stock product.
Richard Feldman

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Rich Feldman
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Re: Stainless steel pipe chamber

Post by Rich Feldman » Sat Jul 01, 2017 4:13 am

Just saw the flat strip idea posted by Ian, within the first few replies to OP. For some reason I can't edit my post from a couple hours ago, to add that acknowledgement.

As for end plate thickness:
I bet Chris will find that the minimum for strength (not bursting under load; optionally springing back to original flatness when load is removed)
is less than the minimum for stiffness (i.e. not deflecting so much that it looks alarming, or interferes with other workings).
Same applies to the design of floor joists in buildings, when the span between supports is large.

Chris, in OP you mention grooves for Viton gaskets. Parker Hannifin's O-Ring Handbook has a wealth of information about design of glands for elastomeric seals. Here's a bit about face seals. https://promo.parker.com/promotionsite/ ... Type-Seals
One non-expert reader, me, notes that the O-ring compression is predictably determined by metal to metal contact. O-ring's job is to seal, not to bear the axial clamping force. Unlike, say, engine head gaskets, or classical bell jars.
Last edited by Rich Feldman on Sat Jul 01, 2017 4:46 am, edited 1 time in total.
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ian_krase
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Re: Stainless steel pipe chamber

Post by ian_krase » Sat Jul 01, 2017 4:36 am

Yeah, ignoring that rule ends badly. Of course rather than grooves you can use shims (like kf centering rings) or chamfers (like O Ring Boss hydraulic fittings).

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