Vertical Roller Mill Bypass Device for Iron Particle Discharge
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Solution Overview
Problem
Vertical roller mills face challenges in efficiently discharging fine iron particles during the grinding process, leading to accumulation on the grinding table and increased energy consumption, which affects the mill's operation and product quality.
Innovation Solution
A vertical roller mill with a bypass device that creates a flow-calmed area between the nozzle ring and the discharge element, allowing for the removal of particles regardless of size and specific weight, reducing iron accumulation and improving throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If iron particles are discharged via the product flow through the classifier, then iron removal is achieved, but fine iron particles accumulate on the grinding table due to pneumatic transport difficulties and classifier rejection
Solution Approach 1:
The bypass device extracts fine iron particles directly from the nozzle ring area where they accumulate, separating them from the main product flow. This extraction mechanism removes the harmful accumulation source without relying on the classifier system that rejects fine particles.
Solution Approach 2:
The bypass device acts as an intermediary discharge path between the grinding table and the external circuit. It provides a dedicated route for fine iron particles that bypasses the classifier system, allowing these particles to be removed without undergoing the rejection process that occurs in the main product flow.
2Loss of substance
If the nozzle ring speed is reduced to eject fine iron particles, then fine iron discharge improves, but the load-bearing capacity and impulse for accelerating product particles to the classifier deteriorate
Solution Approach 1:
The bypass device extracts fine iron particles directly from the nozzle ring area, eliminating the need to reduce overall nozzle ring speed. This extraction approach removes fine particles while maintaining the high-speed operation necessary for proper product particle acceleration and load-bearing capacity.
3Loss of substance
If a magnetic separator is used in the external circuit to remove iron, then coarse iron particles are discharged, but fine iron particles are transported back to the plate due to high nozzle ring speed
Solution Approach 1:
The bypass device serves as an intermediary discharge path specifically for fine iron particles, positioned to intercept them before they are accelerated back onto the grinding table by the high-speed nozzle ring. This intermediate capture point allows fine particle removal while maintaining the high-speed operation needed for coarse particle discharge through the magnetic separator.
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 bypass device effectively prevents iron accumulation on the grinding table, reduces energy consumption, and enhances the mill's operational efficiency by enabling the discharge of fine iron particles, thus improving the grinding process and product quality.
Implementation Method 1
The iron must be transported pneumatically to the classifier
Implementation Method 2
The at least one bypass device creates a flow-calmed area at the location of the bypass device in the nozzle ring
Implementation Method 3
the iron particles fall through the nozzle ring and are then removed from the material flow in the external material circuit by a magnetic separator
Data Source
Figure 1~2
Figure 3a~3b
AI summary
The invention relates to a vertical roll mill (10) comprising a bypass device (70) for discharging particles that are difficult to grind, e.g. ductile particles such as iron particles, from the grinding process.