Two-Stage Filter Device for Cooling Lubricant Degassing
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Solution Overview
Problem
Existing filter devices are not efficient in separating gas bubbles, particularly air, from fluids like cooling lubricants, leading to foaming and overflow issues in machining processes due to the inability to effectively coalesce and remove finely dispersed air bubbles.
Innovation Solution
A two-stage degassing filter device with inner and outer filter elements having specific fold densities (0.1-3 folds/cm and 3-7 folds/cm respectively) that coalesce and separate gas bubbles through a combination of coalescence and Salvinia effect mechanisms, allowing for efficient gas separation and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single filter element is used for gas separation, then the device structure is simple, but the gas separation efficiency is insufficient
Solution Approach 1:
The filter device is divided into two distinct filter elements with different pleat densities. The first filter element has a higher pleat density (3-7 pleats/cm) for initial gas separation, while the second filter element has a lower pleat density (0.1-3 pleats/cm) for final gas release. This segmentation allows each element to perform its specific function optimally, resolving the contradiction between structural simplicity and separation efficiency.
2Area of stationary object
If filter elements have high pleat density, then filtration area is increased, but gas bubble coalescence is reduced
Solution Approach 1:
Different regions of the filter device are assigned different pleat densities based on their specific functions. The first filter element (inner region) uses high pleat density to maximize filtration area for capturing fine gas bubbles, while the second filter element (outer region) uses low pleat density to create larger void spaces that facilitate gas bubble coalescence and release. This local differentiation resolves the contradiction between filtration area and coalescence capability.
3Reliability
If filter elements have low pleat density, then gas bubble coalescence is improved, but filtration area is reduced
Solution Approach 1:
The filtering function is segmented between two filter elements. The first element with high pleat density provides the necessary filtration area for capturing fine bubbles, while the second element with low pleat density provides the coalescence environment. This segmentation allows both high filtration area and effective coalescence to coexist in the overall system.
4Device complexity
If only one filter stage is used, then device complexity is low, but gas discharge rate is insufficient
Solution Approach 1:
The gas separation process is segmented into two stages: first, the high pleat density filter element captures and separates fine gas bubbles from the liquid, and second, the low pleat density filter element facilitates coalescence and release of larger gas bubbles. This two-stage segmentation significantly increases the overall gas discharge rate compared to a single-stage system, while maintaining reasonable structural 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
Significantly improves gas discharge rates and prevents foaming by effectively coalescing and removing air bubbles from cooling lubricants, ensuring stable fluid levels and preventing overflow in machining processes.
Implementation Method 1
a suitable media layer with coalescence properties is used. This layer consists of a fleece with a predetermined pore size gradient, which, starting from a fine structure at the innermost point, gradually transforms into a coarse structure toward the downstream side. As fluid flows through the outer filter medium, this results in the bubbles, which are usually finely dispersed in the fluid, being combined into volumetrically larger units due to the coalescence properties of the media layer
Implementation Method 2
A larger gas bubble generally has a higher buoyancy force, so that it can be more easily removed from the liquid by rising more quickly within it
Implementation Method 3
DE 10 2018 118 139 A1 discovered that hydrophobic surface structures in the form of grid-like structures could retain a layer of gas on the surface underwater. This property is technically known as the Salvinia effect, which describes the stabilization of an air layer on a surface beneath a liquid.
Data Source
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AI summary
2. Filter device comprising at least two filter elements (10, 12) arranged one behind the other in the direction of fluid flow, characterized in that the two filter elements (10, 12) serve to separate gases from the fluid, each encompassing an interior space (28) with its inner circumference (30, 14), wherein, in the direction of fluid flow, the outer filter element (12) has a pleat density of 0.1 to 3 pleats per cm measured along its inner circumference (14) and the inner filter element (10) has a pleat density of 3 to 7 pleats per cm measured along its inner circumference (30).