Rotating Coalescer with Directed Liquid Drainage Gap
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Solution Overview
Problem
Rotating coalescers in crankcase ventilation systems face inefficiencies due to liquid carry-over, which reduces filtration efficiency and complicates the positioning of gas flow outlets, as centrifugal forces eject coalesced liquid droplets back into the airflow, potentially re-entraining them into the filtered stream.
Innovation Solution
A rotating coalescer design with a housing that includes a gap between the filter media and the coalescer housing, featuring a circumferential ring near the gas outlet to prevent liquid re-entrainment, and angled or ribbed surfaces to facilitate liquid drainage away from the gas outlets, ensuring separated liquids are directed to a separate outlet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotating coalescer is used to enhance filtration efficiency through centrifugal force, then particle capture and liquid separation are improved, but liquid droplets are ejected along the axial height and may be re-entrained into the filtered gas stream
Solution Approach 1:
A stationary housing structure is introduced as an intermediary between the rotating coalescer and the gas outlet. This housing provides a controlled environment where centrifugal forces can act on liquid droplets without allowing them to reach the gas outlet, effectively mediating between the separation process and the filtered gas discharge
Solution Approach 2:
The design transitions from a simple axial discharge arrangement to a multi-dimensional housing structure with radial and axial components. The housing creates a three-dimensional flow path that allows filtered gas to exit axially while liquid droplets are contained and drained radially or axially through separate pathways
2Productivity
If rotation speed is increased to enhance centrifugal separation, then liquid separation efficiency is improved, but liquid droplets are ejected with greater force towards the gas outlet
Solution Approach 1:
The housing structure converts the harmful effect of high-speed liquid ejection into a beneficial separation mechanism. The centrifugal forces that would otherwise eject liquid toward the gas outlet are instead utilized to press liquid droplets against the housing walls, where they can be efficiently collected and drained through dedicated liquid outlets
3Productivity
If gas outlet is positioned directly opposite the rotating coalescer outer diameter for optimal flow, then gas flow efficiency is improved, but separated liquid droplets are directly ejected towards the outlet
Solution Approach 1:
The housing structure segments the discharge functions by providing separate outlets for gas and liquid phases. The gas outlet is positioned for optimal flow efficiency while the liquid outlet is positioned to receive centrifugally ejected droplets, eliminating the conflict between flow efficiency and contamination prevention
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 effectively prevents liquid re-entrainment into the filtered gas stream, enhancing filtration efficiency and allowing for flexible positioning of gas and liquid outlets, thereby improving the overall performance of the coalescing process.
Implementation Method 1
By rotating the filter media, inertial impaction and gravitational forces are enhanced by the additional centrifugal force
Implementation Method 2
the contaminants (e.g., oil droplets suspended and transported by blowby gases) are separated inside the filter media of the filter cartridge through the particle capture mechanisms of inertial impaction, interception, diffusion, and gravitational forces onto the fibers
Implementation Method 3
the contaminants (e.g., oil droplets suspended and transported by blowby gases) are separated inside the filter media of the filter cartridge through the particle capture mechanisms of inertial impaction, interception, diffusion, and gravitational forces onto the fibers
Implementation Method 4
Additionally, the rotation of the filter cartridge can create a pumping effect, which reduces the pressure drop through the filtration system
Data Source
AI summary
A rotating coalescer having an ejected coalesced liquid separating device is described. The separating device prevents re-entrainment of liquid into a stream of filtered gas. The rotating coalescer includes a rotating filter element or coalescing cone stack positioned within a rotating coalescer housing. The outer surface of the rotating filter element or the outlet of the coalescing cone stack is displaced from the inner surface of the rotating coalescer housing. The gap between the rotating filter element or the coalescing cone stack and the rotating coalescer housing allows for ejected coalesced liquid, such as oil, to accumulate on the inner surface of the rotating coalescer housing for drainage and allows for filtered gas, such as air, to exit through a clean gas outlet of the rotating coalescer housing.