Re: Re: Butt Welded HDPE Pipe

From: <Pete''s>
Date: Mon May 17 2004 - 20:31:00 EDT

Steve
I've been following the bead situation. I just want to hear how you resolve it. Don't leave us hanging. I'm curious how you are going to get rid of it too.

Pete

• Original Message ----- From: Steve McKenzie To: PipingDesign@yahoogroups.com Sent: Monday, May 17, 2004 2:39 AM Subject: RE: [PipingDesign] Re: Butt Welded HDPE Pipe

   Thanks Tony
   I reckon the Re is about 2 million so there you have it. Surprised the    laminar transition would have such an effect. Must check it out. One    day.............

   Cheers

   Steve

   -----Original Message-----
   From: Tony Paulin [mailto:tony@paulin.com]    Sent: Monday, May 17, 2004 5:01 PM
   To: PipingDesign@yahoogroups.com
   Subject: [PipingDesign] Re: Butt Welded HDPE Pipe

   Re: Weld beads and pipeline friction

   Hans Bos passed on the following comment I thought might be helpful:

   Whether it is important or not depends on the Reynolds number. If flow is    low and the design Reynolds number is in the laminar tubulence transition    the bead could make the boundary layer change to turbulent and then the    friction increases. If the flow is turbulent anyway the bead should hardly    be of importance.

   Tony

   -----Original Message-----
   From: Steve McKenzie [mailto:mechproj@xtra.co.nz]    Sent: Friday, May 14, 2004 4:35 PM
   To: PipingDesign@yahoogroups.com
   Subject: [PipingDesign] Butt Welded HDPE Pipe - Friction Loss Due To    Weld Beads

   Gents
   an HDPE supplier/installer has been asked by his client to debead the    weld inside an HDPE pipeline. The reason given is thought to be    increased pipeline friction due to the weld beads.    The line is 1400mm OD (18m lengths), 56mm wall and the beads are said    to be 10mm high (which seems a little low to me). I did a few rough    sums treating the weld as an orifice plate. The outcome was that the    weld friction loss is less than 3% of the pipe friction loss, which    didnt surprise me.
   I am looking for an authoritative (quotable) study/reference on this    subject.
   Any leads?
   Thanks

   Steve

   [Non-text portions of this message have been removed]

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[Non-text portions of this message have been removed] Received on Mon May 17 20:31:00 2004