Tool Holder Throttling for Liquid CO2 Cooling Pressure Retention
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Solution Overview
Problem
Existing tool holders fail to maintain high pressure and prevent premature evaporation of alternative cooling fluids like liquid CO2, which is essential for effective cryogenic process cooling, leading to inefficient cooling performance.
Innovation Solution
A tool holder design with a throttle point arranged in a sealing piece that is elastically flexible or oscillating about a longitudinal axis, maintaining high pressure by positioning it close to the tool shank and allowing gradual throttling along the fluid channel, with a cross-sectional ratio less than 0.5 to prevent excessive evaporation, and separate fluid channels for CO2 and conventional cooling lubricants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid CO2 is pumped through the tool holder to cooling holes, then cooling effect is achieved, but premature evaporation occurs due to pressure drop
Solution Approach 1:
The throttle point is positioned upstream in the fluid supply path, before the cooling holes, to pre-establish high pressure conditions. This preliminary throttling action ensures that liquid CO2 maintains sufficient pressure throughout the tool holder, preventing premature evaporation before reaching the cutting edge.
Solution Approach 2:
The patent introduces an intermediary throttling mechanism (throttle point with adjustable throttle element) that mediates between the high-pressure supply and the cooling holes. This intermediary component controls the pressure transition, allowing liquid CO2 to remain in liquid phase longer while still achieving the desired cooling effect at the tool.
2Stress or pressure
If throttle point is positioned close to tool shank, then pressure is maintained high, but cooling distribution may be uneven
Solution Approach 1:
The fluid supply system is segmented into multiple cooling holes distributed throughout the tool holder and tool. The throttle point feeds liquid CO2 to these multiple outlets, ensuring that pressure is maintained across all cooling points while distributing the cooling effect uniformly across different areas of the tool and workpiece.
Solution Approach 2:
The patent implements local quality by positioning multiple cooling holes at different locations (e.g., in the tool shank, tool body, and near the cutting edge) with potentially different orientations and sizes. This allows each location to receive optimized cooling based on its specific thermal requirements, while the upstream throttle point ensures sufficient pressure reaches all locations.
3Temperature
If conventional cooling lubricants are used, then cooling is achieved, but alternative fluids like liquid CO2 provide better cooling for demanding materials
Solution Approach 1:
The tool holder is designed with universal adaptability to accommodate multiple cooling concepts. The fluid supply system with adjustable throttle point can handle both conventional cooling lubricants and alternative fluids like liquid CO2 or liquid nitrogen. The system's pressure control mechanism and cooling hole configuration can be adapted to optimize performance for different fluid types and machining applications.
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 maintains high pressure for the cooling fluid, reducing evaporation and ice formation, providing a uniform and effective cooling effect at the tool cutting edge, while allowing for targeted cooling and reduced thermal load.
Implementation Method 1
the throttle point is arranged in a sealing piece which rests against the tool shank and is elastically flexible and/or oscillates about a longitudinal axis in a stop part arranged in the tool holder. This ensures that the pressure of the fluid is kept high for as long as possible and thus no premature evaporation of the fluid occurs.
Implementation Method 2
Only at the actual point of action, i.e., as close as possible to the tool cutting edge, should the remaining liquid CO2 expand and cool the tool cutting edge by absorbing evaporation energy from the environment.
Implementation Method 3
In the so-called snow jet cooling process, liquid CO2 is pumped to the point of action, where it expands and forms a mixture of dry ice and cold gas.
Implementation Method 4
the sealing piece which rests against the tool shank and is elastically flexible and/or oscillates about a longitudinal axis
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A tool arrangement comprising a tool holder 1 and a tool 2, wherein the tool arrangement includes at least one fluid channel 24 for supplying a fluid to the tool 2. To enable improved supply of alternative fluids to the tool, the fluid channel 24 has at least one throttling point 49 upstream of the throttling point 49 for maintaining pressure within the fluid channel 24, which is suitable for maintaining the pressure on the fluid at a level sufficient to prevent excessive premature evaporation of the fluid.