Beta Roller Mill Offset Upper Roller Grinding
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Solution Overview
Problem
Existing grinding technologies for hard and brittle materials, such as high-pressure roller mills and belt roller mills, face limitations in throughput, speed behavior, energy utilization, and mechanical construction, leading to inefficiencies and high maintenance needs.
Innovation Solution
A beta roller mill design featuring two rollers with the upper roller offset and adjustable hydro-pneumatic pressure, allowing for specific grinding forces and controlled material layer thickness, enabling efficient grinding with high peripheral speeds and reduced mechanical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high-pressure roller mill is used to achieve high grinding pressure, then grinding effectiveness is improved, but machine construction becomes complex and heavy
Solution Approach 1:
The grinding process is segmented into two distinct stages: pre-grinding in a ball mill and final grinding in the vertical roller mill. This segmentation allows each device to be optimized for its specific function, enabling the VRM to operate at high pressures without requiring the entire system to be overly complex and heavy.
Solution Approach 2:
Material is pre-ground in a ball mill before being fed to the vertical roller mill for final grinding. This preliminary action reduces the material size and complexity beforehand, allowing the VRM to focus on achieving high-pressure final grinding without dealing with large, unprocessed material chunks.
2Force
If high-pressure roller mill operates at very high pressures, then grinding capability is improved, but throughput and speed behavior become unfavorable
Solution Approach 1:
By dividing the grinding process into pre-grinding and final grinding stages, the system can optimize throughput at each stage. The ball mill handles high-volume pre-grinding, while the VRM focuses on high-pressure final grinding, achieving both high throughput and high pressure capability.
Solution Approach 2:
The system changes operating parameters between stages: the ball mill operates at lower pressures with high throughput, while the VRM operates at high pressures (600-3000 kN/m²) with optimized speed parameters (0.5-3.0 m/s) for final grinding, achieving both high pressure and favorable throughput behavior.
3Ease of operation
If plate conveyor is used to introduce material layer, then material preparation is achieved, but mechanical losses increase and maintenance effort rises
Solution Approach 1:
The plate conveyor is completely removed from the system. Instead, material is introduced directly into the grinding zone between the grinding roller and the bed plate, eliminating the mechanical losses and maintenance issues associated with plate conveyors while still achieving proper material preparation and layer formation.
Solution Approach 2:
The grinding roller itself serves the dual function of both grinding and material conveyance. The rotational movement of the grinding roller naturally introduces and positions the material layer in the grinding zone, eliminating the need for separate conveyor mechanisms and reducing mechanical losses.
4Force
If grinding roller is placed hydro-pneumatically on horizontally guided plate conveyor, then pressure application is achieved, but material intake is impaired causing jams and overflows
Solution Approach 1:
Instead of placing the grinding roller on a horizontal plate conveyor, the system inverts the arrangement by using a vertically oriented grinding roller that rotates in a vertical plane. The material is fed horizontally onto the bed plate, and the rotating vertical roller applies pressure and grinds the material as it passes through the grinding zone, eliminating intake jams and overflows while maintaining effective pressure application.
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 beta roller mill achieves linear throughput speed behavior, high energy utilization, and reduced maintenance, capable of processing a wide range of materials with improved quality and efficiency compared to traditional mills.
Implementation Method 1
the upper roller arranged offset above the driven roller is placed hydro-pneumatically on the material-occupied load surface of the driven roller and is subjected to specific pressure forces in the range of 2 to 7.5 kN/mm
Data Source
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AI summary
In the preliminary grinding and finishing of mineral and non-mineral materials, e.g. limestone, cement clinker, blast-furnace slag, old concrete or ashes, the grinding material, usually comprising new and recirculated stock, is fed as a defined and laterally bounded material layer (4) of predetermined thickness from a material-supply container (3), belonging to the comminuting apparatus, by way of a roller-type or rotary-vane feeder (9), which is arranged at the outlet and can be changed in a stepless manner in respect of its rotational speed, onto the vertex of the laterally rimmed (45), driven, bottom roller (1), accelerated to the roller speed and transported continuously into the gap formed (5) with the top roller (2), arranged in an offset manner above the driven roller (1), is subjected to hydropneumatic loading using specific compressive forces of 2 to 7.5 kN/mm and is then deagglomerated within the comminuting apparatus by a preferably high-speed rotary crusher (10). This results in good utilization of energy and in low mechanical structural, servicing and maintenance outlay. Usage over a wide spectrum for comminuting different materials is made possible, and linear throughput and speed behaviour both in partial-load operation and with high mass throughputs can be realized.