RE: Modeling Hygienic Unions

From: <Ken>
Date: Thu May 20 2004 - 18:42:00 EDT

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=eR3yDk7ToM2xORzXhu9mx5V4w6_oV65E3XBRhSrp8viD9I2mi996owz9vrYbOgGtvsUoMSwKrpTF">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 18:42:00 2004