Conical Impact Mill Cryogenic Comminution and Noise Reduction
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Solution Overview
Problem
Conically-shaped impact mills face inefficiencies in comminution at cryogenic temperatures due to initial particle temperature rise, inability to adjust particle size, and noise issues with power transmission, particularly when processing elastic particles and maintaining or replacing parts.
Innovation Solution
The impact mill design includes a conical rotor with impact knives, an adjustable grinding gap, and a segmented grinding track with variable knife configurations for enhanced comminution control, along with a sprocketed drive system for reduced noise and improved power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If particles are frozen using cryogenic fluids to enable effective comminution of elastic particles, then comminution effectiveness is improved, but temperature gradient causes rapid temperature rise reducing comminution effectiveness
Solution Approach 1:
The patent applies preliminary action by pre-freezing particles with cryogenic fluid before they enter the comminution zone, ensuring they are in a brittle state for effective comminution. The system prepares particles in advance at optimal low temperature before the comminution process begins.
Solution Approach 2:
The patent extracts the temperature control function by introducing a separate cryogenic fluid delivery system that independently manages particle temperature. This allows temperature control to be decoupled from the mechanical comminution process, addressing the temperature gradient issue.
2Reliability
If impact mills are designed with fixed dimensions to maintain structural integrity, then device reliability is improved, but particle size range is fixed and cannot be adjusted
Solution Approach 1:
The patent applies dynamics by making the mill casing adjustable rather than fixed. The mill casing can be repositioned to change the grinding gap between the rotor and stator, allowing particle size adjustment while maintaining structural integrity through controlled mechanical adjustment mechanisms.
Solution Approach 2:
The patent segments the mill structure into adjustable components, particularly the mill casing that can be divided into sections for independent adjustment. This allows modification of the grinding chamber dimensions without compromising the overall structural reliability of the device.
3Power
If conventional power transmission systems are used in impact mills, then power transmission is achieved, but noise levels are excessive
Solution Approach 1:
The patent replaces conventional mechanical power transmission systems (gears, belts) with a direct drive electric motor system. This substitution eliminates or significantly reduces the mechanical components that generate noise, while maintaining effective power transmission to the rotor.
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
This design initiates comminution at lower cryogenic temperatures, allows for precise particle size adjustment, and reduces noise levels during operation, enhancing comminution efficiency and maintenance efficiency while maintaining effective power transmission.
Implementation Method 1
Impact mills, on the other hand, rely on centrifugal force, wherein particle comminution is effected by impact between the circularly accelerated particles, which are constrained to a peripheral space, and a stationary outer circumferential wall
Implementation Method 2
The first expedient employed in changing particle size is changing the feedstock temperature by contact with a cryogenic fluid, e.g. liquid nitrogen, to freeze the elastic solid particles to a crystalline state
Data Source
Figure 1
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Figure 3~5C
AI summary
An impact mill including a base portion on which is disposed a rotor rotatably mounted in a bearing housing, the rotor having an upwardly aligned cylindrical surface portion coaxial with the rotational axis. The impact mill is provided with a mill casing within which is located a conical track assembly which surrounds the rotor to form a conical grinding path. The mill casing is provided with a downwardly aligned cylindrical collar which may be axially adjusted to set a grinding gap between the rotor and the mill casing. The rotor is provided with a plurality of impact knives complementary with a plurality of impact knives disposed on the inside top surface of the mill casing. In addition, the impact mill can be formed of separated conical sections. Finally, power is transmitted to the rotor of the impact mill by a synchronous sprocketed belt, accommodated by a sprocket drive sheave, wherein the belt is in communication with a power source.