Replaceable Turret Bearing Segmentation
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Solution Overview
Problem
Existing turret bearing systems for offshore vessels, such as those using integrated three-row roller bearings, lack the ability for in-situ replacement, leading to maintenance challenges and potential corrosion due to exposure to harsh sea environments, while wheel and rail bearings offer replaceability but with lower load capacity and exposure to corrosion.
Innovation Solution
A turret bearing system comprising three discrete bearings, including a sealed axial thrust roller bearing, a mid radial bearing, and an upper retaining thrust bearing, designed to be individually segmented and replaceable in-situ, with a removable axial spacer allowing for maintenance without disrupting the turret's alignment or rotation capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If integrated three-row roller bearings are used, then load capacity and reliability are improved, but the ability to replace components in-situ deteriorates
Solution Approach 1:
The bearing assembly is divided into separable components: an inner ring assembly that rotates with the turret and an outer ring assembly that remains stationary on the vessel. This segmentation allows the inner ring assembly to be removed and replaced independently in-situ, combining the high load capacity of roller bearings with maintainability.
2Ease of repair
If wheel and rail bearings are used, then ease of repair is improved, but load capacity and reliability deteriorate
Solution Approach 1:
The wheel-and-rail mechanical system is replaced with a roller bearing system that provides superior load capacity and reliability while maintaining replaceability through segmentation. The roller elements provide more efficient load distribution and higher reliability, yet the segmented design enables in-situ replacement similar to wheel-and-rail systems.
3Ease of manufacture
If bearings are exposed to sea environment, then ease of manufacture is improved, but corrosion and failure increase
Solution Approach 1:
A sealed enclosure is provided that isolates the roller elements and lubricant from the corrosive sea environment. The seal prevents water and contaminants from entering the bearing while retaining the lubricant, protecting against corrosion and failure without significantly complicating the manufacturing process.
4Object-affected harmful factors
If sealed bearing arrangements are used, then protection from corrosion is improved, but ease of repair deteriorates
Solution Approach 1:
The sealed bearing assembly is segmented into removable components, with the inner ring assembly designed to be detached as a unit from the outer ring assembly. This segmentation allows the sealed unit to be removed and replaced in-situ without requiring disassembly of the seal itself, maintaining both corrosion protection and ease of repair.
Data Source
AI summary
A turret/vessel bearing arrangement and method for replacing bearings in situ without removing other bearings. The bearings are capable of being separated. A removable axial spacer secures the vessel and the turret into engagement with the upper and lower thrust bearings. Removal of the spacer allows increased separation between vessel and turret flanges that sandwich the thrust bearings. The mid radial bearing assembly includes one or more radially arranged bearing pads that allow for limited axial displacement of the turret with respect to the vessel during thrust bearing replacement while still bearing radial loads and allowing rotation. The addition of a temporary thrust bearing allows the vessel to weathervane about the turret while thrust bearing are replaced in situ.