Thermo-Mechanical Test of Seal System in Flexible Pipe End Fittings

Lars Banke

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    Abstract

    The purpose of the end fitting seal system is to provide a leak tight termination in a flexible pipe. The seal system in a NKT flexible pipe end fitting consists of a number of ring gaskets mounted on the polymeric internal pressure sheath of the pipe. When the seal is energised the gaskets are driven radially into the barrier layer and supported by the surrounding steel casing. In order to verify the integrity of the concept the seal system is subjected cyclic pressure and temperature variations to simulate the service conditions.The aim of the testing is to demonstrate the sensitivity of the seal system geometry and its tolerances necessary to maintain a tight seal. The test is carried out in a purpose built autoclave, in which the seal system can be tested while undergoing variations in pressure and temperature.The paper will present a study on the importance of the geometry of the gasket and the inner liner. The inner and outer diameter of the gasket are varied to see the effectiveness of the seal mechanism. The effect of varying the width of the gasket as well as the surface roughness of the components in the seal system is analysed. Finally, it is investigated how the seal system is affected by minor scratches in the surface of the inner liner.For each test the gasket is subjected to a variation in pressure and temperature. The pressure is cycled at controlled rate to 75000 psi and the temperature to 130oC to simulate relatively onerous operational conditions that could be expected in typical offshore pipeline applications.
    Original languageEnglish
    Title of host publicationMarinflex
    Place of PublicationLondon
    Publication date1999
    Publication statusPublished - 1999
    EventMarinflex - London
    Duration: 1 Jan 1999 → …

    Conference

    ConferenceMarinflex
    CityLondon
    Period01/01/1999 → …

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