Re: Bolting Loose

We think that the problem probably is due to the variation cyclic of temperature. It would be recomended to make a study maybe in a software simulation of the whole system, including the column and the Reboiler? The Nylock that you are refering to is the same that the one called Nord LockŪ?

• In PipingDesign@yahoogroups.com, Christopher Wright <chrisw@s...> wrote:
  >
  > On May 17, 2005, at 9:18 AM, alejandroperezposada wrote:
  >
  > > I'm having some problems with the heads of a Heat Exchanger
  related
  > > with the bolts. The Bolts are loosening in operation.
  > Typically bolts loosen because they aren't tightened properly. When
  the
  > bolt is subject to cyclic loading the joint slips and the nut
  loosens.
  > There are lots of reasons why bolts won't maintain a preload, from
  > bolts that are too short or flanges that squash out over time or
  poor
  > understanding of the actual loading. Bellevilles and those worse
  than
  > useless split washers won't maintain a preload. Depending on the
  > circumstances, you might have some luck with thread locking
  compounds
  > or special locking threads. Nylock nuts sometimes work. As a last
  > resort you can stake the threads, but you can't reuse the bolt and
  it's
  > a bear getting it loose.
  >
  > Christopher Wright P.E. |"They couldn't hit an elephant at
  > chrisw@s... | this distance" (last words of Gen.
  > .......................................| John Sedgwick,
  Spotsylvania
  > 1864)
  > <a href="http://www.skypoint.com/~chrisw/">http://www.skypoint.com/~chrisw/</a>