Vertical Roller Mill Material Distribution Device
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Solution Overview
Problem
Vertical roller mills face issues with uneven material distribution on the grinding table, leading to non-uniform grinding bed heights and pressures, resulting in uneven wear, reduced efficiency, and increased vibrations, which limit the maximum operating speed and throughput.
Innovation Solution
A device is installed in front of each grinding roller to actively peel off material from the grinding table, ensuring a uniform material flow and density, allowing for higher rotational speeds and increased throughput by preventing material accumulation and compression variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If material is fed centrally into the grinding bowl and rotated to distribute evenly, then material distribution should be uniform, but non-uniform grinding bed height forms due to varying material flow and inner circulation
Solution Approach 1:
The invention introduces a material distribution device that actively distributes material across the grinding bowl surface before the grinding process begins. This preliminary action ensures uniform material spread and consistent grinding bed formation, addressing the issue of non-uniform material distribution caused by varying material flow and inner circulation patterns.
2Reliability
If grinding bed height varies across the bowl surface, then hydraulic damping must constantly adjust roller positions, but this leads to uneven roller wear and reduced grinding efficiency
Solution Approach 1:
The material distribution device performs preliminary spreading of material to create a uniform grinding bed before grinding rollers engage. This prevents height variations that would otherwise require constant hydraulic adjustment, thereby reducing uneven roller wear and improving grinding efficiency.
3Speed
If grinding bed is non-uniform, then vibrations occur during mill operation, but these vibrations limit maximum operating speed and throughput
Solution Approach 1:
The material distribution device creates a uniform grinding bed in advance, eliminating the source of vibrations caused by uneven material distribution. This allows the mill to operate at higher speeds without vibration-induced limitations, thereby increasing throughput and maximum operating speed.
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 solution achieves a uniform grinding bed, reducing vibrations and wear, enabling higher throughput and efficiency by ensuring consistent material supply to the grinding rollers, thus allowing the mill to operate at increased speeds and capacities.
Implementation Method 1
As the grinding bowl rotates, centrifugal force transports the material from the center towards the edge of the bowl, accelerating it in the direction of rotation.
Implementation Method 2
since this acceleration occurs solely through friction at the surface
Implementation Method 3
the grinding rollers are not supplied with a uniform flow of material to be ground in a uniform grinding bed
Data Source
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AI summary
The invention relates to a vertical roller mill having a rotatable grinding bowl on which, during operation, a grinding bed composed of material for grinding is formed. Furthermore, at least two stationary rotatable grinding rolls are provided which roll on the material for grinding during operation, wherein the material for grinding is fed to the grinding rolls by rotation of the grinding bowl. According to the invention, provision is made for a device for peeling the material for grinding to be arranged upstream of each grinding roll, and for a part of the peeled material for grinding to be removed upstream of the grinding roll.