Vertical Wet Grinding Mill With Interleaved Discs for Lower Wear
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Solution Overview
Problem
Existing wet grinding mills face inefficiencies due to high energy consumption, uneven bead distribution, and wear issues, particularly in vertical mills, which affect the grinding efficiency and maintenance costs.
Innovation Solution
A vertical wet grinding mill design with a cylindrical housing and interleaved rotor and stator discs, featuring wedge-shaped blades and adjustable annular channel dimensions, allows for uniform centrifugal forces and reduced tip speeds, enhancing grinding efficiency and minimizing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high tip speeds are used to create effective grinding in vertical mills, then grinding efficiency is improved, but energy consumption increases and heat generation causes wear issues
Solution Approach 1:
The patent changes the operating parameters by reducing tip speed from conventional high speeds (15-17 m/s) to lower speeds (5-10 m/s), while compensating through optimized mill geometry (height-to-diameter ratio) and bead size distribution to maintain effective grinding at the reduced speed
Solution Approach 2:
The patent introduces adjustable annular channel dimensions and variable bead size distribution to dynamically optimize the grinding environment, allowing the system to adapt to different material characteristics and operating conditions to maintain efficiency at lower speeds
2Productivity
If high centrifugal forces are used to create annular grinding area in horizontal mills, then grinding effect is improved, but the volume available for grinding becomes small compared to total mill volume
Solution Approach 1:
The patent inverts the conventional horizontal mill design by adopting a vertical orientation, allowing the full mill volume to be utilized for grinding rather than confining the grinding action to a thin annular region, thereby increasing the effective grinding volume while maintaining effective centrifugal forces
3Ease of repair
If polyurethane discs are used to reduce maintenance costs, then wear resistance is improved, but heat sensitivity causes reduced durability under high energy consumption conditions
Solution Approach 1:
The patent changes the operating parameters by reducing tip speeds and energy consumption, thereby reducing heat generation to levels that polyurethane discs can withstand without deforming or failing, thus maintaining both the maintenance cost advantage and reliability
4Duration of action of stationary object
If steel discs are used in slim high mills for soft materials, then tool lifetime is improved, but hydraulic pressure at the bottom causes highest wear in the bottom part
Solution Approach 1:
The patent applies different bead size distributions at different heights within the mill, with larger beads in the bottom region and smaller beads in the top region, creating localized grinding characteristics that reduce wear in the high-pressure bottom area while maintaining effective grinding throughout the mill volume
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 design achieves more efficient grinding with lower energy consumption and reduced wear, enabling the mill to handle abrasive materials like ores with improved operational efficiency and reduced maintenance needs.
Implementation Method 1
The rotating speed of the discs turns the coarse material comprising the material to be ground and grinding media, normally ceramic material referred to as beads, creating a centrifugal field with high pressure on the annular milling areas ensuring the grinding effect
Implementation Method 2
The force for accelerating the coarse material is produced by the friction between the coarse material and the surface of the discs. Most of the energy consumed for grinding is converted in to heat
Data Source
AI summary
A mineral liberation machine comprising vertical wet grinding mill (10) for grinding coarse material comprising a cylindrical housing (14) containing a rotatable shaft (15) creating an annular channel (17) with an input feed (16) for supplying coarse material and an output feed (18) for withdrawing ground product, in which the rotatable shaft (15) is equipped with a plurality of rotor discs (20) and the cylindrical housing (14) is equipped with one or more stators or stator discs (22), the discs (20, 22) on the rotatable shaft (15) and cylindrical housing (14) are interleaved such that the ratio of the height of the housing (14) to the diameter of the housing (14) is low with the diameter to height ratio being between 0.6-1.2.