Fluid-Activated Shaft Seal Using Expanding Gel
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Solution Overview
Problem
Conventional shaft seals, such as the ND-type seal, prematurely activate and fail due to friction-induced wear when dry, and are inadequate in sealing effectiveness at low pressure differentials, leading to excessive leakage in industrial applications like shipbuilding, where self-activating and fluid-tight seals are required for various shaft diameters.
Innovation Solution
A fluid-activated shaft bulkhead seal system utilizing a gel material that expands when exposed to fluid, separating from the shaft in the absence of fluid to prevent wear and only engaging with the shaft when a fluid is present, thereby reducing friction and ensuring a tight seal across a range of diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional shaft seals are designed to rotate with the shaft during operation, then sealing effectiveness is improved, but friction-induced wear causes premature failure
Solution Approach 1:
A bearing is introduced as an intermediary component between the seal assembly and the shaft. The bearing supports the shaft and enables it to rotate independently, while the seal assembly remains stationary. This mediator allows the shaft to pass through and rotate without causing the seal to rotate, thereby eliminating friction-induced wear on the seal components while maintaining effective sealing.
2Duration of action of moving object
If shaft seals are designed to be stationary to prevent wear, then seal component life is improved, but sealing effectiveness against rotating shafts deteriorates
Solution Approach 1:
The sealing system is segmented into distinct functional components: a stationary seal assembly and a rotating shaft supported by a bearing. The seal assembly remains fixed to prevent wear, while the bearing handles the rotational motion. This segmentation allows each component to perform its specific function optimally - the seal provides static sealing without wear, and the bearing manages dynamic rotation.
3Reliability
If shaft seals activate at low pressure differentials to ensure fluid-tight sealing, then leakage prevention is improved, but accelerated wear occurs leading to premature failure
Solution Approach 1:
The bearing acts as a mediator that supports the shaft and absorbs the effects of pressure differentials and rotational forces. By introducing this intermediary, the seal assembly can remain stationary and only activate when truly needed, rather than continuously reacting to pressure changes. This reduces accelerated wear while maintaining fluid-tight sealing capability.
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
The gel material expands to create a robust, reversible seal that significantly reduces leakage rates and prolongs seal life by minimizing friction and ensuring compliance with stringent industrial leakage specifications, even under low pressure differentials.
Implementation Method 1
a fluid-activated shaft bulkhead seal system that incorporates a gel material and a seal
Implementation Method 2
contact between the sealing components and the shaft while the sealing components are dry leads to premature failure of the sealing components caused by the associated friction-induced wear
Data Source
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AI summary
Systems and methods associated with a fluid-activated shaft seal are provided. The systems, which feature multiple components, include a support component (804) defining an exterior surface (848), a carrier component (808) including an interior surface (832) to slideably engage the exterior surface of the support component, and a seal (812) disposed relative to the carrier component. The seal (816) includes a lip portion and a fluid- responsive gel material that expands when exposed to a fluid to urge the lip portion towards or into contact with a shaft. The gel material contracts in the absence of the fluid to form or increase the size of a gap between the shaft and the lip portion. Methods of assembling and installing such a. system are also described. A system for confining and/or securing an alignment/interface ring is described.