RE: [PipingDesign] RTJ gasket behaviour under pressure.

Kevin ,
  i am just sharing my thoughts as i have a very little experience of 4 years,expert in this group can focus more on this issue .

1. your 1st question- what happens when the lines expand due to high pressure ?- my answer -When system becomes operational, and temperature and pressure builds up, flanges are subjected to Pressure pulls and bending due to moment created. Much of this gets countered by Bolts which are tightened as per pressure rating of the flanges.Gaskets also go under the deformation and provides the leak tightness. But gaskets should not be crushed all together by the external forces/moments to continue providing leak tightness. Yes gaskets do bounce back to fill in the minute openings which are created due to above reasons to maintain the leaktightness
2. your 2nd question -Do these gaskets have enough resilience to bounce back the amount equal to the gap that is created due to pressure expansion and maitain leak tightness? Normally how much gap these flanges make (of course this would depend upon the internal pressure) that is covered by ring's resilience? my answer- Not none to me, but all depands how much bending moment flanges can take which is again dependent on flange rating (PCD of bolts, No of bolts, bolt types etc)
3. your 3rd question -So does this create any leakage problem in case of ring type gaskets?

  my answer- Resilience type gasket information need to be obtained from the vendor who can tell you about the crushing strength it may have. I am not sure about the sprial or ring type but resilience type gaskets are better for leak tightness.

With Regards

Shailendra Kulkarni
Stress Analysis Dept.

Black and Veatch Consulting Pvt. Ltd,
Pride Parmar Galaxy 10/10+A, 3rd floor,
Sadhu Vaswani Chowk, Pune 411001,
Maharashtra, India
Ph: 020-30537325
Cell:9850585122
Email- kulkarnis2@bv.com

From: PipingDesign@yahoogroups.com [mailto:PipingDesign@yahoogroups.com] On Behalf Of Kevin Green
Sent: Monday, May 19, 2008 4:43 PM
To: PipingDesign@yahoogroups.com
Subject: [PipingDesign] RTJ gasket behaviour under pressure.

Dear All,
The rtj gasket ring deforms when the flange bolts are tightened. The deformed ring makes the shape of the groove in the flange. The ring (I believe) undergoes the plastic deformation. This deformation is beyond the elastic range of both soft iron and other materials for gaskets. SO...
What happens when the lines expand due to high pressure? Do these gaskets have enough resilience to bounce back the amount equal to the gap that is created due to pressure expansion and maitain leak tightness?
Normally how much gap these flanges make (of course this would depend upon the internal pressure) that is covered by ring's resilience? So does this create any leakage problem in case of ring type gaskets? And finally, is the behaviour of ring type gasket better than spiral wound as far as leakage is concerned?
kg

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Received on Tue May 20 05:17:00 2008