Stacked V-Packing Shaft Seal Structure for Sequential Wear
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Solution Overview
Problem
Conventional V-packings with stacked sealing portions pressed against each other experience significant wear, leading to a shortened useful lifetime of the shaft seal.
Innovation Solution
A shaft sealing structure featuring multiple V-packings or U-packings with thick-walled top portions and thin-walled inner and outer skirt portions, where adjacent skirt portions do not interfere with each other, allowing for sequential wear and prolonged sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple V-packings are stacked and pressed strongly against each other to achieve stable sealing, then sealing performance is improved, but wear on all packings progresses simultaneously leading to shortened lifetime
Solution Approach 1:
The sealing structure is divided into multiple independent V-packing segments stacked in sequence. Each V-packing can wear independently without affecting the others, allowing sequential replacement rather than simultaneous replacement. This segmentation transforms the wear problem from a system-level issue to individual component-level issues.
Solution Approach 2:
The V-packings are designed as consumable sealing elements that can be individually replaced when worn. Rather than designing for simultaneous longevity of all components, the system accepts that individual packings will wear and can be economically replaced one at a time, extending the overall system lifetime.
2Reliability
If V-packings are pressed strongly against the valve rod and valve body to prevent liquid leakage, then sealing performance is improved, but wear on the sealing portions increases
Solution Approach 1:
By dividing the sealing function into multiple V-packing segments, the wear burden is distributed across several components. Each packing experiences wear but the cumulative sealing performance is maintained longer, and worn packings can be individually replaced without affecting the entire sealing system.
Solution Approach 2:
The design accepts that V-packings will wear and become discarded, but this is manageable because they are modular components that can be individually replaced. The system recovers sealing performance by replacing only the worn individual packings rather than the entire sealing assembly.
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 structure maintains satisfactory sealing performance over an extended period by distributing wear among the packings, ensuring continuous effective sealing without simultaneous degradation.
Implementation Method 1
The inner side skirt portion (18) and the outer side skirt portion (20) are both formed to be thin-walled, and slide in contact with the rod (32) and the holder (34), respectively
Data Source
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AI summary
A shaft sealing structure (12) includes a plurality of V-packings (14a to 14c) that are stacked in multiple stages, and each of the V-packings is formed of a thick-walled annular top portion (16), a thin-walled inner side skirt portion (18), and a thin-walled outer side skirt portion (20). Adjacent ones of the top portions abut against each other, adjacent ones of the inner side skirt portions do not interfere with each other, and adjacent ones of the outer side skirt portions do not interfere with each other.