Flexible Bellows Seal for Coiled Spring Assembly Dust Protection
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Solution Overview
Problem
The existing coiled spring assembly in pulverizer mills, such as bowl mills, lacks a suitable seal that allows for visual inspection of the spring stud while maintaining a seal against atmospheric pressure, leading to premature failure due to coal dust ingress.
Innovation Solution
A cylindrical, flexible seal is integrated into the coiled spring assembly, secured to both the spring adjustment bolt and bearing assembly and the mounting ring, allowing axial, radial, and angular movement of the preload stud while preventing coal dust from entering the bushing area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid extension cap is used to seal the spring assembly, then coal dust ingress is prevented, but visual inspection of the spring stud becomes impossible without removal
Solution Approach 1:
The patent replaces the rigid extension cap with a flexible bellows seal that can accommodate axial movement of the spring stud while maintaining seal integrity. The bellows structure allows the seal to expand and contract with spring stud motion, enabling continuous visual inspection without compromising protection against coal dust ingress.
2Ease of operation
If the extension cap is removed to inspect the spring stud, then visual inspection is enabled, but coal dust can enter the bushing assembly causing premature failure
Solution Approach 1:
The flexible bellows seal provides continuous protection against coal dust while allowing the spring stud to move axially for inspection purposes. This eliminates the need to remove the seal entirely, thereby preventing coal dust ingress that would otherwise cause premature bushing failure.
Solution Approach 2:
The bellows seal transitions from a static rigid cap to a dynamic flexible structure that adapts to the moving spring stud. This dynamic capability allows the seal to maintain its protective function throughout the full range of spring stud motion, including during inspection operations.
3Reliability
If a seal is added to the coiled spring assembly, then coal dust ingress is prevented, but the complexity of the assembly increases
Solution Approach 1:
The bellows seal, while adding a component, uses a simple yet effective flexible membrane structure that accommodates motion without requiring complex mechanisms. The bellows design provides seal integrity through its inherent flexibility rather than through complex active control or multiple components.
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
Enables continuous visual inspection of the spring stud without removing the extension cap, maintaining a positive seal and preventing coal dust from entering the assembly, thus extending the lifespan of the bushing and spring stud.
Implementation Method 1
a seal being substantially cylindrical shaped and flexible at least along a central axis thereof
Data Source
AI summary
A coil spring assembly for connection with a separator body to apply a spring force to a grinding roll of a journal assembly to pulverize solid fuel. The coil spring assembly includes: a preload stud having a first end in communication with the journal assembly and an exposed opposite second end extending from the coil spring assembly; a spring adjustment bolt and bearing assembly being fixed relative to the preload stud extending therethrough; and a seal being substantially cylindrical shaped and flexible at least along a central axis thereof. The seal has a first end operably secured to the spring adjustment bolt and bearing assembly and an opposite second end operably secured to the second end of the preload stud thereby sealing a bushing area corresponding to a portion of the preload stud surrounded by the spring adjustment bolt and bearing assembly from ground solid fuel dust and allowing movement of the preload stud at least along the central axis thereof to apply the spring force from the coil spring assembly to the grinding roll.