Session: CT-01-01 Design and Analysis of Bolted Flange Joints-1

Paper Number: 124123

124123 - A Simple Method for Calcualting Accurate Gasket Stresses for Octagonal Ring Joints 

Abstract

The goal of this paper is to serve as a guide to end-users that are developing torque guidelines for use with octagonal ring joint gaskets.  Surprisingly, there is no readily available resource to guide end-users in determining the gasket seating stress on octagonal ring joint gaskets.  To fill this void, this paper describes the trigonometric relationships that determine the gasket seating stress on the sloped sealing surfaces of octagonal ring joints using a simplified cross-sectional model of the rings.  Furthermore, it describes a basic conceptual model that simplifies the formulae, reducing them to a load/area relationship.  Finally, it shows that the simplified cross-sectional model used in this study – and also used by major refining organizations – induces a significant error.  We show the formulaic corrections that eliminate this error – resulting in improved seating stress modeling.

The greater accuracy of these results leads to meaningful questions – raised in the concluding discussion.  In light of this data, what reasonable limits are needed to prevent over-compression of the ring at assembly, ensure minimum stud stress, prevent flange rotation, and seal robustly at MAWP?  While some tentative answers are offered, further discussion with industry stakeholders will undoubtedly be needed before such guidance can be included in PCC-1.       

Presenting Author: David Clover LGG Industrial

Presenting Author Biography: David Clover is the Senior Gasket Product/Application Specialist with LGG Industrial (Formerly ERIKS North America), with 40-years' experience in the gasket industry. His principal roles are:
• Engineering problem solving. Discovering the underlying causes of leakage, and recommending solutions based on improved materials and procedures.
• Teaching. Building and conducting technical seminars across North America.

David is a voting member of the ASME B16.20 Committee.

He lives on a 10-acre farm in Spokane, Washington, with Shirley, his wife of 40-years, and an assortment of horses, chickens, cats and dogs.

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