Replaceable Seat Seal Assembly for BOP Ram Cavity Refurbishment
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Solution Overview
Problem
The prolonged and costly process of repairing and refurbishing blowout preventers (BOPs) due to wear and tear, which can lead to performance issues and the risk of cracks if not done properly, necessitates a more efficient and reliable solution.
Innovation Solution
A replaceable seat seal assembly for BOPs that includes machining pockets in the worn areas of the ram cavity and throughbore to accommodate inserts, forming a new seal that matches the original's tolerances, allowing for field replacement without extensive welding or heat treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional repair and refurbishment process (machining, welding, heat treatment) is used to restore BOP body, then the BOP can be brought back to operative condition, but the process takes approximately 45 days and carries high risk of crack development
Solution Approach 1:
The invention divides the BOP body into two segments: a permanent outer shell and a replaceable inner liner. The liner contains the wear-prone ram cavity and throughbore surfaces, allowing it to be independently replaced without refurbishing the entire BOP body. This segmentation enables quick replacement of worn surfaces while preserving the intact outer shell, reducing refurbishment time from 45 days to a fraction of that time.
Solution Approach 2:
The inner liner is designed as a consumable component with a finite service life. When the liner becomes worn or damaged, it is replaced rather than refurbished. This approach treats the liner as a short-living component that can be economically replaced, avoiding the costly and time-consuming process of welding and heat treatment required to restore the permanent outer shell.
2Manufacturing precision
If traditional repair process (welding and heat treatment) is used to refurbish BOP body, then worn surfaces can be restored, but there is high chance of crack development affecting performance
Solution Approach 1:
By segmenting the BOP body into a permanent outer shell and a replaceable inner liner, the invention isolates the wear and repair issues to the liner component only. The outer shell maintains its original manufacturing precision and remains crack-free. The liner can be replaced when worn, eliminating the need for welding and heat treatment on the critical outer shell structure.
Solution Approach 2:
The invention extracts the wear-prone ram cavity and throughbore surfaces from the permanent BOP body structure by placing them inside the replaceable liner. This extraction allows the critical outer shell to remain untouched and free from repair-induced cracks, while the liner bears the wear and can be replaced without affecting the structural integrity of the main body.
3Reliability
If extensive machining and welding is performed to refurbish BOP body, then the original seal can be restored, but the process is prolonged and costly
Solution Approach 1:
The invention segments the refurbishment task by isolating the seal-critical surfaces (ram cavity and throughbore) into a separate replaceable liner component. This allows the permanent outer shell to remain intact, and only the liner needs to be replaced when seals wear. The liner replacement process is much faster and less costly than traditional welding and heat treatment, significantly improving refurbishment efficiency while maintaining seal integrity.
Solution Approach 2:
The liner is designed as an economical, replaceable component with a defined service life. When the liner's seal surfaces become worn, the entire liner is replaced rather than refurbished. This approach is more cost-effective and time-efficient than performing extensive machining and welding on the expensive permanent BOP body, while ensuring seal integrity is restored through a like-new liner installation.
Data Source
AI summary
A replaceable seat seal assembly is used to form a replaceable portion of the ram cavity in a BOP that allows the central portion of the ram cavity to be replaced when wear occurs. A method is provided to refurbish a BOP that has a worn ram cavity with a replaceable portion of the ram cavity. The replaceable seat seal assembly includes a plurality of inserts such as a top insert, bottom insert, and two side inserts. The inserts of the replaceable seat seal assembly are positioned within one or more pockets or recesses machined into the ram cavity and throughbore. The inserts can be readily replaced for convenient maintenance without the need for heat treatments, welding, and the like that is normally needed to repair a used ram cavity.