Re: Vibration

You need to measure both the velocity and the frequency (we're using the Bentley Nevada instrument/recorder) of the pipe along its span. Then you need to check youre reading againts the severity chart. If outside the limit, then obviously a fix is needed. If the vib reading is OK, then there is nothing more to do except to monitor it from time to time.

If the limit has been exceed and you decided either to re-route the pipe or add support, then a stress calc needs to be performed. After the fix , then do another vib survey to validate the work. This is on the assumption that the process line is still in good shape and meets the spec.

You can find a copy of the severity chart either in EDI or Carmagen website.

• In PipingDesign@yahoogroups.com, Dacharaju Krishnamohan Rao <dk_rao@...> wrote:
  >
  > Mr Imran,
  >
  > visit "http://www.engdyn.com/pulsation/pipingfld.htm" which
  provides
  > some published papers on the subject.
  >
  > regards,
  > D.K.M.Rao.
  >
  >
  >
  >
  > "Farhad" <farhad_ss@...>
  > Sent by: <a href="/group/PipingDesign/post?postID=HrkopjMtjwFW2Ozh_5HANX3qe-j4_9YtkJkvBkIZGJ2fFjtIQvHmWPt5QSfJS1jOkG1rtvJiNK22m6eCs0bNUWn3hB4CJA">PipingDesign@yahoogroups.com</a>
  > 02/12/2007 03:15 PM
  > Please respond to
  > <a href="/group/PipingDesign/post?postID=HrkopjMtjwFW2Ozh_5HANX3qe-j4_9YtkJkvBkIZGJ2fFjtIQvHmWPt5QSfJS1jOkG1rtvJiNK22m6eCs0bNUWn3hB4CJA">PipingDesign@yahoogroups.com</a>
  >
  >
  > To
  > <a href="/group/PipingDesign/post?postID=HrkopjMtjwFW2Ozh_5HANX3qe-j4_9YtkJkvBkIZGJ2fFjtIQvHmWPt5QSfJS1jOkG1rtvJiNK22m6eCs0bNUWn3hB4CJA">PipingDesign@yahoogroups.com</a>
  > cc
  >
  > Subject
  > [PipingDesign] Vibration
  >
  >
  >
  >
  >
  >
  > Dear Imran,
  >
  > Definitely, you should use CAESAR II software to solve this
  problem.
  > There are a few steps as follows:
  >
  > 1- Collect field data (displacements, RPM of pumps, pipe support
  > configuration, etc.)
  > 2- Model piping system in CAESAR II.
  > 3- Run static analysis.
  > 4- perform Harmonic analysis and enter harmonic displacement at
  pump-
  > pipe node.
  > 5- Tweak some dynamic parameters to model exact problem.
  > 6- Add some stiffness (pipe support) to your piping system,
  wherever
  > possible.
  > 7- Run static then dynamic analysis to see changes.
  >
  > I hope it helps you.
  >
  > Regards,
  > Farhad
  >
  > --- In PipingDesign@yahoogroups.com, "Imran M Ahmed" <imahmed@>
  > wrote:
  > >
  > > Hello Guys!
  > >
  > >
  > >
  > > We are facing vibration problem in the piping system of our
  plant.
  > The
  > > scenario is that the lean Amine pumps operate with a vibration
  of
  > approx
  > > 6 mm/sec pk on DE and 3.8 mm/sec pk on NDE. The vibration gets
  > > transmitted through the piping into the standby pump which is
  not
  > in
  > > operation. The vibration recorded on the standby pump is
  > approximately
  > > 3.0 mm/sec pk. Do you have suggestion how to control this
  > vibration?
  > >
  > >
  > >
  > > Regards,
  > >
  > >
  > >
  > > Imran Ahmed
  > >
  > >
  > >
  > >
  > >
  > > [Non-text portions of this message have been removed]
  > >
  >
  >
  >
  >
  >
  >
  >
  >
  >
  >
  > -------------------------------------------------------------------
  

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