Valve Stem Filler Sealing Structure to Prevent Graphite Loss
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Solution Overview
Problem
High-temperature normal-pressure valve stem sealing structures using graphite filler components experience material loss, leading to crawling and insufficient sealing, resulting in media leakage.
Innovation Solution
A straight-stroke no-material-loss high-temperature normal-pressure filler sealing structure is designed with a combination of scraper rings, primary-secondary fillers, support rings, and a graphite sealing ring, along with a drive load detection unit, to prevent material loss and maintain stable sealing. The structure includes an upper valve cover, valve stem, filler component, and filler gland, with a wedge-shaped metal ring connection and annular storage groove to enhance radial sealing force and reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If graphite filler components are used for valve stem sealing under high temperature conditions, then sealing capability is improved, but material loss occurs leading to insufficient sealing force and media leakage
Solution Approach 1:
The filler component is segmented into multiple layers including scraper rings, primary fillers, secondary fillers, and support rings. This segmentation allows each layer to perform specific functions: scraper rings remove excess graphite, primary/secondary fillers provide sealing, and support rings maintain structure. This prevents material loss by ensuring only necessary graphite contacts the valve stem.
Solution Approach 2:
The scraper rings are designed to discard excess graphite material that would otherwise be lost during operation. By scraping off surplus graphite, the system recovers material that would otherwise be wasted, while maintaining optimal sealing conditions without excessive material deposition.
2Reliability
If graphite material is deposited on valve stem surface during operation, then initial sealing is achieved, but valve stem crawling occurs and sealing force becomes insufficient
Solution Approach 1:
The harmful effect of graphite deposition is addressed by extracting the excess material through scraper rings. The scraper rings actively remove surplus graphite from the valve stem surface, preventing the accumulation that leads to crawling while maintaining the necessary sealing layer.
Solution Approach 2:
The graphite material that would normally cause harm through excessive deposition and crawling is converted into a benefit by using it as a controlled sealing layer. The scraper rings manage this material transformation, allowing graphite to provide sealing where needed while removing it where it would cause crawling.
3Device complexity
If traditional filler sealing structure is used, then simple structure is maintained, but material loss leads to frequent maintenance and reduced service life
Solution Approach 1:
The filler component is divided into multiple functional segments (scraper rings, primary fillers, secondary fillers, support rings) that work together to prevent material loss. This segmentation, while adding structural complexity, dramatically extends service life by preventing the material loss that would otherwise require frequent maintenance.
Data Source
AI summary
The present disclosure provides a straight-stroke no-material-loss high-temperature normal-pressure filler sealing structure, comprising: an upper valve cover with an accommodation cavity; a valve stem, passing through the accommodation cavity of the upper valve cover; a filler component, located in the accommodation cavity and sleeved on the valve stem; a filler gland sleeved on the valve stem, whose bottom is inserted into an opening of the accommodation cavity.