Slurry Blasting Descaling Cell for Sheet Metal Scale Removal
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Solution Overview
Problem
The existing methods for removing scale from sheet metal, such as pickling and oiling, are costly, environmentally hazardous, and require significant space and resources, with pickling lines being expensive and oiling processes being time-consuming and labor-intensive, while also necessitating immediate application to prevent oxidation.
Innovation Solution
A slurry blasting process using a descaling apparatus with centrifugal impellers that propels a grit-containing slurry across the sheet metal surfaces, removing scale and creating a rust inhibitive layer without the need for acids or oils, reducing operational costs and space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pickling and oiling process is used to remove scale from sheet metal, then scale removal effectiveness is improved, but operational costs increase and environmental hazards worsen
Solution Approach 1:
The patent replaces the chemical pickling system with a mechanical slurry blasting system that uses abrasive particles to remove scale. The slurry blasting apparatus propels abrasive-laden slurry against the sheet metal surface at high velocity, achieving scale removal through mechanical impact rather than chemical dissolution, thereby eliminating environmental hazards associated with acid baths and oil applications
Solution Approach 2:
The patent employs hydraulic principles by using a slurry (liquid-particle mixture) that is propelled through a piping system and delivered to the sheet metal surface. The slurry blasting system utilizes fluid dynamics to transport and deliver the abrasive slurry efficiently, replacing the chemical bath approach with a controlled fluid delivery mechanism that reduces environmental impact
2Manufacturing precision
If pickling lines are installed to remove scale, then scale removal capability is improved, but capital costs and space requirements increase
Solution Approach 1:
The patent extracts the essential scale removal function from the complex pickling line infrastructure. By isolating the scale removal capability into a standalone slurry blasting apparatus, the system eliminates the need for extensive pickling line equipment, large acid storage facilities, and complex waste treatment systems, thereby reducing capital costs and space requirements while maintaining effective scale removal
3Reliability
If oiling process is applied immediately after pickling, then oxidation prevention is improved, but labor costs and processing time increase
Solution Approach 1:
The slurry blasting process provides self-service oxidation protection by creating a surface condition that inherently resists oxidation. The abrasive blasting action produces a clean, activated surface that forms a protective layer during the blasting process itself, eliminating the need for separate oiling operations and associated labor and time costs
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 slurry blasting process effectively removes scale, producing a rust inhibitive product that eliminates the need for pickling and oiling, reducing operational costs by 30-50% and capital costs by 66%, while minimizing environmental impact and space usage.
Implementation Method 1
The eductor has a nozzle adapted to produce a vortex flow
Implementation Method 2
A slurry blasting process using a descaling apparatus with centrifugal impellers that propels a grit-containing slurry across the sheet metal surfaces
Implementation Method 3
propelling a scale removing medium, specifically, a liquid/particle slurry, against the surfaces of the material passed through the apparatus
Implementation Method 4
The rate of slurry impact against the sheet metal is controlled such that the slurry impact alone removes substantially all of the scale from the metal
Data Source
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AI summary
A method is provided for removing iron oxide scale from sheet metal and producing a sheet metal surface with rust inhibitive properties. The sheet metal is advanced through the descaling cell and a slurry mixture is propelled against at least one of the top surface and bottom surface of the sheet metal across the sheet metal width as the material is advanced through the descaling cell. The rate of slurry impact against the at least one of the top surface and bottom surface of the sheet metal is controlled in a manner to remove substantially all of the scale from a surface of the sheet metal, and in a manner to create a passivation layer on the descaled surface of the sheet metal. The passivation layer comprises at least one of silicon, aluminum, manganese and chromium and inhibits oxidation of the descaled surface of the processed sheet metal.