Planetary Roller Mill High Moisture Feed Drying
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing roller mills are not configured to efficiently process high moisture feed materials, as they lack sufficient heat for drying and calcining, and are limited by speed and vibration issues that restrict throughput and particle size refinement.
Innovation Solution
A planetary roller mill with a grinding assembly designed to operate at high air temperatures, eliminating the need for lubricants, and featuring a unique support plate configuration to optimize air flow and contact pressure between rollers and the grinding ring, allowing for efficient drying and calcining of high moisture feed materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional roller mills are used to process high moisture feed material, then the grinding function is provided, but insufficient heat is available for drying and calcining the material
Solution Approach 1:
The patent combines the grinding function with drying and calcining functions in a single integrated system. The grinding assembly is positioned within a drying assembly that provides heated air flow, allowing simultaneous grinding, drying, and calcining of high moisture feed material without requiring separate equipment.
Solution Approach 2:
The grinding assembly serves multiple functions: it grinds the feed material while simultaneously exposing it to heated air for drying and calcining. This multi-functional design eliminates the need for separate drying and calcining equipment, directly addressing the insufficient temperature issue in conventional roller mills.
2Temperature
If high air temperatures are used for drying and calcining, then moisture removal is improved, but lubricants required for roller operation degrade or fail
Solution Approach 1:
The patent eliminates the need for lubricants by removing the vulnerable journal assembly and bearing structures from the high-temperature zone. The rollers are designed to operate without traditional lubrication systems, extracting the problematic lubricant component entirely from the high-temperature environment.
Solution Approach 2:
The grinding assembly is designed to operate autonomously without external lubrication systems. The rollers function through direct mechanical contact and gravitational force, eliminating dependency on lubricants that would otherwise fail under high temperature conditions.
3Productivity
If the mill operates at high speed to increase throughput, then productivity improves, but vibrations increase and restrict further speed increases
Solution Approach 1:
The patent employs dynamic balancing of the rotating grinding assembly to minimize vibrations at high operating speeds. The planetary roller configuration and support structure are designed to accommodate and dampen vibrational forces, enabling sustained high-speed operation without excessive vibration that would restrict throughput increases.
4Manufacturing precision
If contact pressure between rollers and grinding ring is increased to improve grinding efficiency, then particle size refinement improves, but the risk of roller damage or wear increases
Solution Approach 1:
The patent optimizes the contact pressure parameters between rollers and grinding ring to achieve effective particle size refinement while maintaining roller structural integrity. The support plate configuration and roller positioning are designed to distribute contact forces evenly, preventing localized stress concentrations that could cause roller damage or premature wear.
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 planetary roller mill effectively processes high moisture feed materials by providing sufficient heat for drying and calcining, while reducing vibrations and increasing throughput, enabling the production of finely ground calcined products.
Implementation Method 1
an air supply system having an outlet in communication with the opening in the grinding ring for supplying air through the opening
Implementation Method 2
configured for grinding the feed material at a grinding zone air temperature of at least 177 degrees Celsius (350 degrees Fahrenheit)
Data Source
AI summary
A planetary roller mill for processing a feed material includes a vessel with a grinding ring having an opening and a first area. The grinding ring is in sealing engagement with an inside surface of the vessel. At least two non-circular support plates are secured to a rotatable shaft. Each plate has an axially facing surface. A plurality of rollers are rotatably mounted to and positioned between the two support plates. Each of the plurality of rollers are in grinding communication with the grinding surface. The planetary roller mill includes an air supply system having an outlet in communication with the opening in the grinding ring. Areas of the two support plates are of magnitudes configuring a flow area through the opening of at least 30 percent of the first area to provide a predetermined quantity of heated air to remove moisture from the feed material in the mill.