Shovel Rotor Encapsulation of Superhard Particles
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Solution Overview
Problem
Existing methods for manufacturing encapsulated superhard materials, such as diamond and cBN, face challenges including slow deposition rates, agglomeration, and non-uniform composition, particularly when using fluidised beds or rotating pans, which impact commercial viability and throughput.
Innovation Solution
A method utilizing a shovel rotor with a vessel equipped with shovels or baffles to rotate and translate superhard material particles, combined with a mixture of organic binder, solvent, and coating materials, allowing for high coating rates with minimal agglomeration by ensuring uniform deposition and mixing of particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fluidised bed method is used to coat particles, then good separation of core seeds is achieved ensuring single core per pellet, but deposition rate is relatively slow and equipment capacity requirements increase cost
Solution Approach 1:
The process is divided into two distinct stages:第一阶段 uses fluidised bed for precise single-core encapsulation,第二阶段 uses rotating pan for rapid mass buildup. This segmentation allows each stage to optimize for its specific function, resolving the contradiction between precision and productivity
Solution Approach 2:
The fluidised bed stage performs preliminary encapsulation to ensure each pellet contains exactly one core seed before transferring to the rotating pan. This preliminary action establishes the precision requirement first, then enables faster subsequent processing
2Quantity of substance
If high density particulate coating material is used, then encapsulating material mass increases, but equipment capability to maintain suspension is exceeded
Solution Approach 1:
The system transitions from a static fluidised bed to a dynamically rotating pan system. The rotation creates centrifugal forces and continuous motion that maintain suspension of high-density materials, allowing greater material mass to be processed without exceeding equipment capabilities
Solution Approach 2:
The process changes the operational parameters by switching from fluidised bed conditions to rotating pan conditions, where gravity, centrifugal force, and rotational speed parameters enable handling of higher density materials with improved suspension maintenance
3Stability of the object's composition
If coating with mix of powders of different densities and particle shapes is performed, then composition uniformity is intended, but material segregation occurs in fluid bed
Solution Approach 1:
The rotating pan creates dynamic conditions with continuous motion, varying contact points, and gravitational effects that prevent material segregation. Unlike the static fluidised bed where density-based separation occurs, the rotating system maintains homogeneous mixing of powders with different densities and shapes throughout the coating process
4Productivity
If rotating pan method is used to build up pellets, then encapsulating material deposition is efficient and pellet mass increases quickly, but agglomeration of cores and early pellets occurs in initial stages
Solution Approach 1:
The fluidised bed stage performs preliminary encapsulation to form stable single-core pellets with proper initial coating. This preliminary action prevents agglomeration by establishing a protective layer around each core before the high-speed rotating pan process begins
Solution Approach 2:
The process segments the encapsulation into two phases:第一阶段 in fluidised bed for precise single-core encapsulation with controlled deposition,第二阶段 in rotating pan for rapid mass buildup. This segmentation allows agglomeration control in the initial stage while achieving high productivity in the subsequent stage
5Manufacturing precision
If slow deposition rate is used in rotating pan method, then agglomeration is avoided, but overall processing time increases and throughput is reduced
Solution Approach 1:
The process divides encapsulation into two segments with different deposition rates:第一阶段 in fluidised bed with controlled slow deposition for precision,第二阶段 in rotating pan with faster deposition for productivity. This segmentation allows both agglomeration avoidance and high throughput to be achieved in different stages
Solution Approach 2:
The system changes operational parameters between stages, using controlled slow deposition in fluidised bed to prevent agglomeration, then transitioning to faster deposition conditions in the rotating pan where the established coating structure prevents agglomeration while enabling higher throughput
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 shovel rotor method achieves high deposition rates comparable to pan granulators while minimizing agglomeration, resulting in efficient production of encapsulated superhard particles with high hit rates and uniform composition, significantly improving the commercial viability of producing encapsulated abrasives.
Implementation Method 1
combining the superhard material and the mixture in the shovel rotor such that the superhard material is carried over the shovels or baffles which add additional rotation and translation thereto; and rotating the rotor at a velocity such that the superhard material is encapsulated by the mixture
Implementation Method 2
providing a mixture comprising (i) an organic binder; (ii) a solvent or fluid medium selected from water, deionised water and organic solvents; and (iii) a coating or encapsulating material selected from metal, metal alloy, ceramic and/or cermet powders or combinations thereof
Data Source
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AI summary
The invention relates to a method of manufacturing encapsulated superhard material, the method comprising the steps of providing a source of superhard material, providing a mixture comprising an appropriate binder, a solvent or fluid medium and the intended coating or encapsulating layer, combining the superhard material and the mixture in a shovel rotor comprising a vessel including a rotor, the vessel adapted to receive a stream of gas; and rotating the rotor at an appropriate velocity such that the superhard material is encapsulated by the mixture. The invention further relates to an encapsulated superhard material produced by a method as hereinbefore described.