Dynamic Variable Sieve Openings in Mill Discharge Grates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional mill discharge grates are prone to pegging and occlusion due to undersized media becoming wedged in fixed sieve openings, leading to reduced open area and frequent replacement needs.
Innovation Solution
A discharge grate with movable, 'floating' screen bars that dynamically expand and contract, utilizing resilient members and a holding frame with receiving openings to accommodate media and pulverized material, reducing pegging and occlusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fixed sieve openings are used in discharge grates, then structural simplicity and ease of manufacture are improved, but pegging and occlusion occur leading to reduced reliability and increased maintenance frequency
Solution Approach 1:
The patent applies the dynamics principle by transitioning from fixed sieve openings to movable screen bars that can dynamically adjust their positions. The screen bars are designed to move independently within guide openings, allowing the sieve opening dimensions to change dynamically in response to operational conditions, thereby preventing pegging while maintaining manufacturing simplicity
Solution Approach 2:
The patent implements parameter changes by allowing the geometric parameters of sieve openings to vary dynamically. The movable screen bars change the opening size and shape based on material flow conditions, transforming the static parameter regime into a dynamic one that adapts to prevent occlusion and maintain reliability
2Reliability
If movable screen bars are used to prevent pegging, then reliability and wear life are improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the discharge grate into multiple independent movable screen bars rather than using a single fixed structure. Each screen bar operates independently within its guide openings, allowing localized movement to prevent pegging without requiring complex coordinated mechanisms across the entire grate structure
Solution Approach 2:
The patent implements self-service through the self-adjusting capability of the movable screen bars. The bars automatically move in response to material pressure and flow conditions without external control, using the operational forces themselves to maintain optimal opening configurations and prevent pegging, thereby reducing the need for complex control systems
3Productivity
If fixed sieve openings become occluded, then open area is reduced requiring grate replacement, but using movable bars increases structural complexity
Solution Approach 1:
The patent uses the dynamics principle to maintain productivity by enabling the screen bars to dynamically adjust their positions to prevent occlusion. This continuous adaptation keeps the open area maximized throughout operation, eliminating the need for premature grate replacement while using relatively simple movable structures within guide openings
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 dynamic variable sieve openings enhance wear life, reduce pegging occurrences, and improve screening performance by allowing temporary expansion for media passage, thereby maintaining mill efficiency and reducing the frequency of grate replacements.
Implementation Method 1
The resilient member (213) may comprise a material which is configured to elastically deform
Data Source
AI summary
A discharge grate (200) for an internal discharge end (3) of a mill (1) may be characterized in that it has at least one dynamic variable sieve opening (206) defined between two adjacent floating screen bars (202). The floating screen bars (202) may be configured to a least temporarily move with respect to one another and/or with respect to a holding frame (201) receiving the floating screen bars (202). Temporary expansion of the at least one dynamic variable sieve opening (206) may permit undersized media to pass to the discharge chute (8) and reduce or eliminate pegging.