Cryogenic Fluid Supply Valve for Stable Machining Pressure Control
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Solution Overview
Problem
Conventional machining methods require significant cooling and lubrication, leading to environmental pollution, high costs, and reduced machining performance due to the use of cutting fluids, while existing alternatives like dry machining and cryogenic machining have limitations in maintaining optimal cooling and lubrication conditions, especially in high-temperature cutting zones.
Innovation Solution
A system that supplies cryogenic fluids like liquid nitrogen to the machining zone, utilizing a control/command device and a 'cold box' to regulate pressure and flow, ensuring safe communication with the machine-tool command cabinet, and employing a self-regulating cryogenic control valve to maintain optimal temperature, pressure, and two-phase rate, with purging and heating functions to prevent blockages and maintain tool integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cutting fluids are used for cooling and lubrication, then machining performance is maintained, but environmental pollution and operational costs increase significantly
Solution Approach 1:
The patent applies inert atmosphere by using liquid nitrogen as a cryogenic cutting fluid替代 conventional cutting oils. Liquid nitrogen provides cooling and lubrication in the cutting zone without producing harmful environmental pollution, chemical pollution of swarf and machined surfaces, or harmful fumes. The inert nitrogen atmosphere eliminates fire hazards and environmental concerns associated with traditional cutting fluids.
Solution Approach 2:
The patent changes the physical parameters of the cutting fluid by using liquid nitrogen at cryogenic temperatures (around -196°C) instead of conventional cutting oils at ambient or elevated temperatures. This parameter change enables effective cooling of the cutting zone while eliminating the harmful effects of traditional cutting fluids. The system controls temperature, pressure, and two-phase rate parameters to optimize machining performance.
2Object-generated harmful factors
If dry machining or micro-lubrication is applied to reduce cutting fluid consumption, then environmental impact is reduced, but machining performance capabilities are degraded
Solution Approach 1:
The patent utilizes phase transitions of liquid nitrogen (liquid to gas) to achieve both cooling and lubrication functions. The liquid nitrogen is supplied in liquid form for efficient cooling, and during the machining process, it undergoes phase transition to nitrogen gas, providing lubrication and swarf removal. This phase transition mechanism enables cryogenic machining to achieve superior machining performance compared to dry machining or micro-lubrication methods.
3Reliability
If liquid nitrogen is supplied to the machining zone, then cooling and lubrication effectiveness is improved, but system complexity and safety requirements increase
Solution Approach 1:
The patent implements self-service through an automated control system that manages liquid nitrogen supply based on machining conditions. The command cabinet communicates with the cryogen implementation equipment to automatically control fluid supply, temperature, pressure, and two-phase rate parameters. The system self-regulates to maintain optimal machining conditions without requiring manual intervention, thereby managing system complexity through automation.
Solution Approach 2:
The patent employs feedback control mechanisms where the command cabinet receives information about machining conditions and adjusts liquid nitrogen supply accordingly. The system monitors and controls parameters such as temperature, pressure, and two-phase rate, providing feedback loops that maintain optimal cooling and lubrication effectiveness while adapting to varying machining requirements.
4Temperature
If high flow rates of cryogenic fluid are used to ensure adequate cooling, then cooling effectiveness is improved, but tool weakness and premature breakage occur
Solution Approach 1:
The patent applies dynamics by making the liquid nitrogen flow rate adjustable and adaptable to specific machining conditions. Rather than using constant high flow rates that could weaken tools, the system dynamically adjusts flow parameters based on the machining operation, tool type, and cutting conditions. This dynamic control ensures adequate cooling effectiveness while preventing tool weakness and premature breakage.
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 system provides efficient and safe cryogenic fluid supply, maintaining optimal machining conditions, reducing tool wear, and enabling consistent machining performance across various machining methods like turning, milling, and drilling, while minimizing environmental impact and tool changes.
Implementation Method 1
The cryogenic fluid can be nitrogen and CO2... providing cryogen (for example, nitrogen) to be provided in liquid form
Implementation Method 2
cooling and lubrication of the cutting zone... heat transfer fluid
Implementation Method 3
a valve which is able to self-regulate its degree of opening as a function of the downstream pressure required, so as to deliver a constant, adjustable pressure and therefore a constant, adjustable flow rate
Data Source
AI summary
A method for machining workpieces, having a cryogenic fluid intake in a machining zone, including locating a valve on the line connecting a fluid source to a machining tool in the machining zone, the valve self-regulates the degree of opening according to the pressure required downstream thereof, the valve is located inside a cold box for implementing the cryogenic fluid and provides a fixed and adjustable pressure, and a fixed adjustable flow, to the machining tool, irrespective of the tool that is used, and the number of orifices and the diameter of the fluid ejection orifices in the tool.