Electric Arc Furnace Lance Positioning via Articulated Linkage
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Solution Overview
Problem
Existing steelmaking lance positioning systems for electric arc furnaces face challenges such as large dimensions, limited reach, complex control systems, and increased heat losses due to the need for a wide opening in the furnace wall, which restricts the range of positioning angles and complicates maintenance.
Innovation Solution
A compact positioning apparatus with an articulated quadrilateral linkage and rotation mechanism that allows the lance to be tilted and rotated within the furnace, minimizing the side wall opening required and enabling optimal injection angles, while maintaining ease of maintenance and use of conventional straight lances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a long arm supporting structure is used to allow the lance to reach the bath, then the injection position can be reached, but the structure becomes heavy and the angle between the lance and bath plane deviates from optimal
Solution Approach 1:
The patent employs a movable supporting structure with articulation joints that allow dynamic adjustment of the lance position and angle. The structure can move between different configurations to maintain optimal injection angles while reaching various positions in the bath, rather than being fixed in a long rigid arm configuration.
Solution Approach 2:
The invention introduces multiple degrees of freedom through articulation joints and movement capabilities along different axes. This allows the lance to reach positions in three-dimensional space while independently controlling the injection angle, separating the constraints of reach distance from angle optimization.
2Ease of operation
If the slag door is left open to allow lance operation, then the lance can be positioned, but heat losses and air flow rate increase
Solution Approach 1:
The supporting structure is divided into separate articulated segments that can be independently positioned. This allows the lance to be inserted through a minimized opening while the rest of the structure remains outside the furnace, reducing the size of the opening required and thereby minimizing heat losses and air infiltration.
3Manufacturing precision
If a complex positioning system is used to optimize lance position, then positioning precision improves, but device complexity and control system complexity increase
Solution Approach 1:
The articulated supporting structure utilizes passive mechanical linkages and gravity-assisted positioning where possible. The system's geometry and mechanical constraints naturally guide the lance to optimal positions without requiring complex active control systems, reducing electronic complexity while maintaining positioning precision.
4Ease of operation
If internal lances are used to maintain optimal injection angle, then injection angle is optimized, but reagents are injected near refractory lining causing erosion
Solution Approach 1:
The supporting structure is designed with dynamic positioning capabilities that allow the lance to maintain optimal injection angles relative to the bath surface while adjusting the distance from the refractory lining. The articulation joints enable independent control of angle and position, preventing the lance from being forced too close to the lining.
Data Source
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AI summary
The present invention relates to a positioning apparatus (100,100',100") for steelmaking lances (300) of an electric arc furnace (200) comprising: - a supporting structure (150,150') for a steelmaking lance intended to be introduced into said furnace (200) through an opening (230) of said furnace - a linkage (110;120;130;160) associated to said supporting structure (150,150') and intended to position a carriage (115) linearly movable with respect to said linkage (110;120;130;160) wherein said linkage (110;120;130;160) is an articulated quadrilateral intended to cause said at least one steelmaking lance (330) to be moved from a parking position outside said electric arc furnace to an operating position wherein at least a part of said lance is inside said electric arc furnace and said positioning apparatus (100,100',100") further comprises rotation means to cause at least said carriage (115) to rotate about an axis (X) substantially vertical in the assembly condition; further aspects of the inventions are also a system and a method for steelmaking.