Marine Propeller Shaft Seal Cooling via Dual Lubrication Circuits
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Solution Overview
Problem
The temperature increase of lubricants in shaft seal arrangements for propeller shafts of marine vessels leads to excessive lubricant consumption and wear of the seal arrangements.
Innovation Solution
Incorporating a heat exchanger system that transfers thermal energy between the lubricant circulation lines for the bearing and shaft seal, allowing for separate lubricant circulation and composition, with circulators to manage lubricant flow and prevent mixing, thereby cooling the lubricants and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shaft seal arrangement is used to seal the propeller shaft against sea water, then sealing effectiveness is improved, but lubricant temperature increases leading to excessive lubricant consumption and wear
Solution Approach 1:
The system separates the lubrication system into two independent circuits: a first lubrication arrangement for the bearing arrangement and a second lubrication arrangement for the shaft seal arrangement. This segmentation allows each circuit to be optimized independently, preventing heat transfer from the shaft seal to the bearing lubricant, thereby reducing lubricant consumption and wear in the shaft seal circuit while maintaining sealing effectiveness.
Solution Approach 2:
A heat exchanger is introduced as an intermediary component between the first and second lubrication arrangements. The heat exchanger transfers thermal energy between the two lubrication circuits, cooling the lubricant in the shaft seal arrangement without direct mixing of lubricants. This mediator component effectively manages thermal energy to reduce lubricant temperature, consumption, and wear while maintaining the sealing function.
2Reliability
If a shaft seal arrangement is used to seal the propeller shaft against sea water, then sealing effectiveness is improved, but wear of the shaft seal arrangement increases due to elevated lubricant temperature
Solution Approach 1:
By dividing the lubrication system into separate circuits for the bearing and shaft seal, the system prevents thermal coupling between the two components. The shaft seal lubricant can be cooled independently through the heat exchanger, maintaining optimal operating temperatures that extend the service life of the shaft seal while preserving sealing effectiveness.
Solution Approach 2:
The heat exchanger acts as a thermal intermediary that selectively cools the shaft seal lubricant without affecting the bearing lubricant. This mediated thermal management reduces the temperature of the shaft seal lubricant, thereby reducing wear and extending the duration of action of the shaft seal arrangement while maintaining its sealing function.
3Temperature
If separate lubrication arrangements are used for bearing and shaft seal, then lubricant temperature control is improved, but device complexity increases
Solution Approach 1:
The system combines the two separate lubrication arrangements through a shared heat exchanger component. While the lubrication circuits remain separate for temperature control, the heat exchanger serves both circuits, reducing the overall complexity compared to having completely independent cooling systems. This merging approach maintains effective temperature control while minimizing device complexity.
Solution Approach 2:
The heat exchanger is designed as a multi-functional component that serves both the first lubrication arrangement (bearing) and the second lubrication arrangement (shaft seal). By making the heat exchanger universal and capable of handling both lubrication circuits, the system achieves effective temperature control without proportionally increasing device complexity, as one component performs multiple thermal management functions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively lowers the temperature of lubricants, reducing their consumption and wear on the shaft seal arrangements, enhancing the longevity and efficiency of the sealing system.
Implementation Method 1
a first heat exchanger in thermal contact with the first lubricant circulation line and in thermal contact with the second lubricant circulation line for transferring thermal energy between first lubricant flowing in the first lubricant circulation line and second lubricant flowing in the second lubricant circulation line
Data Source
AI summary
An arrangement and a method for sealing a propeller shaft of a marine vessel. The arrangement includes a propeller shaft rotatable supported with at least one bearing, a bearing arrangement, a first lubrication arrangement including a first lubricant circulation line for conducting first lubricant to and from the bearing arrangement, a shaft seal arrangement for sealing the propeller shaft against sea water, and a second lubrication arrangement including a second lubricant circulation line for conducting second lubricant to and from the shaft seal arrangement. A first heat exchanger is in thermal contact with the first lubricant circulation line and in thermal contact with the second lubricant circulation line.