Cryogenic Milling Chamber with Cooling Jacket for Heat Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current milling technologies face challenges in scaling up cryogenic milling operations due to equipment design limitations, contamination risks with cryogenic liquids, and mechanical integrity issues at cryogenic temperatures.
Innovation Solution
A novel design for a cryogenic milling chamber that uses a monolithic body with a cooling jacket for efficient heat exchange, allowing for cryomilling without direct contact between the cryogen and the powders, and featuring improved thermal control and mechanical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional milling is performed at ambient temperature, then the milling process is simple to operate, but the material softens and welds to the milling media and chamber walls, reducing milling effectiveness
Solution Approach 1:
The patent applies parameter changes by transitioning the milling process from ambient temperature to cryogenic temperatures (using liquid nitrogen cooling). This temperature parameter change prevents material softening and cold welding, maintaining milling effectiveness while operating continuously without interruptions for cooling or material replacement.
Solution Approach 2:
The patent introduces liquid nitrogen as an intermediary cooling medium that circulates through a cooling jacket surrounding the milling chamber. This intermediary system provides continuous cooling without direct contact between the cryogen and the material being milled, resolving the contradiction between operational simplicity and milling effectiveness.
2Temperature
If cryogenic milling is performed with direct contact between cryogen and powders, then cooling efficiency is maximized, but contamination of the powders with cryogenic liquid occurs
Solution Approach 1:
The patent segments the cooling system into two separate zones: the milling chamber containing the powders and milling media, and the cooling jacket containing the cryogenic liquid. This segmentation allows efficient heat transfer through the chamber walls while preventing direct contact and contamination of the powders with the cryogen.
Solution Approach 2:
The chamber walls act as an intermediary thermal conductor, transferring heat from the powders to the cooling jacket without requiring direct contact between the cryogen and the material being processed. This resolves the contradiction between cooling efficiency and contamination prevention.
3Manufacturing precision
If milling is performed at cryogenic temperatures, then material brittleness increases improving particle size reduction, but mechanical components may lose structural integrity
Solution Approach 1:
The patent applies parameter changes by carefully controlling the temperature parameter within the cryogenic range, maintaining it above the ductile-brittle transition temperature of the milling chamber and component materials. This allows the processed material to become sufficiently brittle for fine size reduction while the structural components retain their mechanical integrity.
Solution Approach 2:
The patent employs composite material selection for the milling chamber and components, using materials with appropriate ductile-brittle transition temperatures that allow the processed material to become brittle while the chamber materials remain ductile and structurally sound at operating temperatures.
4Productivity
If scale-up of cryogenic milling is attempted, then production capacity increases, but equipment design complexity and cooling system requirements increase significantly
Solution Approach 1:
The patent applies universality by designing a modular cooling jacket system that can be adapted to milling chambers of various sizes. The same basic cooling jacket design principle applies across different scales, with the system serving multiple functions: cooling the chamber, removing heat from the milling process, and preventing contamination. This modular approach enables scale-up without proportionally increasing design complexity.
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
Enables efficient and reliable cryomilling operations at various scales, preventing contamination and maintaining mechanical integrity, while ensuring uniform temperature conditions and improved powder refinement and alloying efficiency.
Implementation Method 1
The milling chamber is equipped with a cooling jacket that facilitates efficient heat exchange
Implementation Method 2
The unique aspect of this novel design addresses the mechanical loads and stresses induced by the thermal gradients within the milling chamber and between the milling chamber and the motor housing mounting plate
Data Source
AI summary
An apparatus and method of mechanical milling and grinding of various materials at temperatures ranging from sub-ambient conditions to well-below their ductile-brittle transition temperature (DBTT) are presented. In one embodiment the present invention entails the design of a cryogenic milling chamber compatible with horizontal high-energy mills. The new design and configuration of the milling vessel provides robust and efficient cryomilling of various materials with no contact between the cryogen and the powders. Some embodiments of the invention improve the heat removal rate from the non-uniform heat load generated by the impact energy deposited into the chamber wall by the milling media.