MQL Lubrication Pump Control for Continuous High-Pressure Flow
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Solution Overview
Problem
Current Minimum Quantity Lubrication (MQL) systems face challenges in achieving consistent and continuous lubricant delivery due to varying fluid viscosity and high pressure requirements, leading to pulsed output and calibration issues, especially in through-the-spindle metal-cutting environments.
Innovation Solution
A method involving a dual-action positive displacement pump system with a high modulus of elasticity lubricant supply line and a controller to maintain a constant and continuous lubricant flow rate, using a combination of pneumatic and fluid control systems to accurately deliver lubricant and air, minimizing expansion and entrapped air for precise fluid delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a metering element is used to control fluid flow by opening and closing rapidly, then the amount of fluid can be controlled, but the system becomes sensitive to viscosity changes and requires manual calibration
Solution Approach 1:
The patent replaces the mechanical metering element system with a volumetric pump system that uses positive displacement to deliver fluid. This substitution eliminates the need for rapid opening/closing mechanical valves and their associated calibration issues, providing consistent fluid delivery based on volumetric measurement rather than time-based metering that is sensitive to viscosity changes.
Solution Approach 2:
The patent changes the control parameter from time-based metering (valve open duration) to volume-based delivery (pump displacement). By measuring and controlling the actual volume of fluid delivered through the volumetric pump, the system becomes insensitive to viscosity changes and eliminates the need for manual calibration of metering elements.
2Stress or pressure
If a volumetric pump is used to deliver fluid at high pressure, then the required pressure can be achieved, but the output rate is much higher than required for MQL applications
Solution Approach 1:
The patent uses a variable speed drive to dynamically adjust the pump's operating speed, allowing the system to deliver the required high pressure while precisely controlling the output rate to match the low flow requirements of MQL applications. The pump speed can be varied to maintain optimal pressure and flow conditions.
Solution Approach 2:
The patent changes the operational parameters of the volumetric pump by adjusting its speed and displacement to achieve the required pressure while limiting the output rate. By controlling the pump's volumetric delivery rate through speed adjustment, the system can provide high pressure (up to 10 bar) while maintaining the low flow rates needed for MQL (1-500 ml/hr).
3Stress or pressure
If a single piston pump is used to deliver low volume fluid shots, then the pump can operate at required pressure, but the output is pulsed and not continuous
Solution Approach 1:
The patent divides the single piston pump into multiple pistons (at least two) that operate in sequence or simultaneously. This segmentation of the pumping action ensures that while one piston may be at the end of its stroke, another is delivering fluid, thereby maintaining continuous output while operating at the required high pressure.
Solution Approach 2:
The patent implements a multi-piston configuration where the pumping action of multiple pistons overlaps and complements each other. This ensures that fluid delivery is continuous without interruption, as at least one piston is always in the delivery phase of its cycle, eliminating the pulsed output characteristic of single piston pumps while maintaining high operating pressure.
4Ease of operation
If the lubricant supply line is flexible, then installation is easier, but the line expands under high pressure causing flow rate variations
Solution Approach 1:
The patent applies different material properties to different sections of the lubricant supply line. The section between the pump and the tool uses a low-expansion material (such as metal or rigid plastic) to maintain flow rate consistency under high pressure, while other sections may use flexible materials for ease of installation. This local differentiation of material quality resolves the contradiction between flexibility and flow consistency.
Solution Approach 2:
The patent employs composite construction for the lubricant supply line, combining materials with different properties. The supply line may use a rigid inner layer or section to prevent expansion under pressure, combined with outer protective or flexible layers. This composite approach allows the line to resist pressure-induced expansion while maintaining installation flexibility through appropriate material selection and design.
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 approach ensures a precise, continuous, and consistent lubricant supply even at high backpressures, reducing calibration needs and minimizing errors, thereby enhancing the accuracy and reliability of lubrication in MQL systems.
Implementation Method 1
a lubricant supply line having a high modulus of elasticity and having at least a portion that is non-expandable and at least a portion that is minimally expandable
Implementation Method 2
at least one volumetric flow pump...supplying a continuous supply of lubricant...at a lubricant flow rate
Data Source
AI summary
A minimum quantity lubrication system for accurately measuring and controlling a volume and pressure of a lubricating fluid provided to a machining tool during minimum quantity lubrication machining operations. The minimum quantity lubrication system can further include measuring and controlling a volume and pressure of air provided during machining such that atomization of the lubricating fluid with the air can be controlled. Use of a continuous volumetric flow pump provides a continuous flow of lubricating fluid to the tool during machining operations.