Abstract
In the end fitting, terminating a length of an API 17J type flexible pipe, there may be a need to provide more than one seal ring to allow both for testing the integrity of the primary seal, and to offer redundancy in the event of a primary seal ring failure. Specifically for the internal seal system at the pressure barrier there may be stress relaxation and creep of the polymer seal layer which could affect the integrity of the seal over time, or there could be galling between the two metals of the seal and the end fitting at the metal-to-metal seal location, which could result in poor or no seal at this location, which is not discovered until the final hydrotest of the completed pipe shows a leak past the end fitting primary seal.
This concept provides a means of secondary seal in incorporation with a primary seal ring, the event of a primary seal ring failure; the concept also doubles up as a test seal, allowing the use of the o ring(s) seal to validate the primary seal ring integrity. There are no new custom metallic sealing parts, and the concept only requires modifications to existing parts. This can be validated at small / mid-scale level. The O-ring metal to metal proven joint removes the need for a test seal ring and there are no additional parts other than O-rings.
The positioning of the O-ring seals – See below figures – nested in the seal ring (or in the opposing end fitting component) provides the ability to test between the O-ring and the metal-to-metal seal between the primary seal ring and the end fitting, ensuring that seal performance, and doing so at the earliest opportunity during the end fitting assembly process, minimizing additional costs which might result from inadequate seal performance.
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Recommended Citation
"Test Seal Ring Elimination and Condition Monitoring", Technical Disclosure Commons, (August 18, 2025)
https://www.tdcommons.org/dpubs_series/8474