Hi Gents:
I've been following this interesting discussion. It would nice to actually see what it is you're attempting to accomplish here, either graphically or in a drawing. However, question I ask is why not weld all the pipe if possible? Use a short leg or place a reducer with heavy duty clamps. On a project I worked on in Shreveport, LA, these were CV lines for steam or nitrogen cured medium voltage cables,, thermal expansion was a major issue with the line extending about three feet over the temp range. We used in case (1) high performance braided/spirally banded flexible hose and in case (2) flexible yoke style couplings (2 required) with a "bent leg" to take up travel due to the expansion of the line. In both cases, this was six inch pipe and extremely hot. Both worked but I can well imagine that they were not fail safe. We used case (1) due to space related issues and considered it a lesser solution, due to the possibility of failures over time. Outfits like UNAFLEX (800)327-1286 supply these, including bellows, high pressure expension compensators. You may have to check with them regarding your application, pipe schedule, sizes, flanging, etc.
Regards
Mike Waugh
www.waudesign.com
-----Original Message-----
From: Ken Nisly-Nagele [mailto:knislynagele@applied-e-s.com]
Sent: Thursday, May 20, 2004 6:43 PM
To: <a href="/group/PipingDesign/post?postID=zUlOZRHrFJmr-7N3TUjzhvwDbKrlL2ZWx--WTAcVeosEMciIqEoagN95emDVYjnlum3Z1Yepb7IQj8aZxYb6TkuTig">PipingDesign@yahoogroups.com</a>
Subject: RE: [PipingDesign] Modeling Hygienic Unions
These clamps are made by Tri-Clover, Waukesha, or Swagelok, and are rated to 200 psig. By meeting code, I mean to demonstrate that the unions will not leak during sterilization. I'm not concerned about the clamps working at the design pressure, but rather, I'm concerned with the clamps leaking when the piping in which they are installed undergoes bending during thermal expansion and causes the faces of the ferrules to spread apart and result in leakage. With standard flanges there are tools to predict leakage, but I am not aware of a way to check for leakage with a union of this type. It may be that the only solution is to ask the manufacturers to test and publish the data as a group or individually.
Ken A. Nisly-Nagele, P.E.
Project Engineer, Mechanical
Applied Engineering Services, Inc.
7999 Knue Road
Indianapolis, IN 46250
317-585-8920
-----Original Message-----
From: Christopher Wright [mailto:chrisw@skypoint.com]
Sent: Thursday, May 20, 2004 5:00 PM
To: ‡
Subject: RE: [PipingDesign] Modeling Hygienic Unions
>My apologies, my initial posting was not sufficiently clear.
No problem. Are you talking about clamps like the Grayloc or Tri-Clover
variety?
>The question is one of
>applying the unions and demonstrating compliance with the code.
I think the easy for doing this is to show that your clamp meets the code
rules for a pressure which produces a unit axial load equal to the
(calculated axial pressure stress + the calculated bending stress)/pipe
wall thickness. This is fairly conservative, but it'll meet the U-2(g)
requirements without a lot a extra work.
Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=8cxrjqq-bGlieBT9odoTg8z8XrZWq8x2ph8m2Vi9z0py5_yDVrEGBfdhJ3VgLdAsaerycsfB8ERjBpJ9">chrisw@skypoint.com</a> | this distance" (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)<a href="http://www.skypoint.com/~chrisw">http://www.skypoint.com/~chrisw</a>
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Yahoo! Groups Links Received on Thu May 20 19:35:00 2004
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