Rotary Vane Compressor Oil Separation With Centrifugal and Mesh Stages

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Solution Overview

Problem

Rotary vane compressors face challenges in efficiently separating oil from compressed gas due to the high-speed rotation and turbulent flow, leading to reduced efficiency, wear, and potential contamination of downstream equipment, especially in vehicle applications where space is constrained.

Innovation Solution

A two-stage oil separation unit comprising a centrifugal separator and a knitted mesh filter is integrated within the compressor housing to leverage the mass inertia and coalescence of oil droplets, enhancing separation efficiency by utilizing centrifugal forces and filtration methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single-stage filtration system is used, then device complexity is reduced, but oil separation efficiency deteriorates

Engineering Contradiction:
Improvefiltration system complexityVSAvoidoil separation efficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The filtration system is divided into two distinct stages: a centrifugal separator for bulk oil removal and a mist separator for fine particle filtration. This segmentation allows each component to specialize in removing different sizes of oil particles, achieving high overall separation efficiency without requiring an overly complex single-stage system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The centrifugal separator acts as an intermediary component between the compressor outlet and the mist separator. It pre-treats the compressed air by removing large oil droplets and water condensate, reducing the load on the downstream mist separator and enabling the entire system to achieve high efficiency without excessive complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a multi-stage filtration process is used, then oil separation efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveoil separation efficiencyVSAvoidfiltration system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system segments oil particle removal into two distinct functional zones: a centrifugal separation zone for bulk removal and a mist filtration zone for fine particles. This segmentation achieves superior separation efficiency while keeping each stage relatively simple in design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system exploits changes in oil particle characteristics during the separation process. Large droplets are removed first by centrifugal force, then smaller aerosol particles are captured by the mist separator. This parameter-based approach (size-based separation) achieves high efficiency with a straightforward two-stage configuration.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the oil sump housing is undersized, then device complexity is reduced, but oil separation efficiency deteriorates

Engineering Contradiction:
Improvehousing sizeVSAvoidoil separation efficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The centrifugal separator performs preliminary action by removing the bulk of oil and water before the air reaches the mist separator. This pre-treatment allows the downstream components to be more compact while still achieving high overall separation efficiency, as the mist separator only needs to handle the remaining fine particles rather than the full oil-laden stream.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If high-speed rotation of vanes is maintained, then productivity is improved, but oil entrainment in gas stream increases

Engineering Contradiction:
Improvecompression speedVSAvoidoil entrainment
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system extracts oil from the compressed gas stream in two sequential operations: first removing bulk oil through centrifugal separation, then extracting fine oil aerosols through mist filtration. This two-stage extraction approach effectively eliminates the harmful oil entrainment generated by high-speed vane rotation while maintaining high compression productivity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The centrifugal separator serves as an intermediary treatment between compression and final filtration, capturing the majority of oil particles generated by high-speed operation. This intermediate step reduces the burden on the downstream mist separator and enables the system to handle high-speed compression with minimal oil carryover.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The two-stage separation process effectively removes oil particles, improving compressor performance and longevity by preventing oil contamination and ensuring optimal operational reliability.

Implementation Method 1

the first separator comprises a centrifugal separator and is configured to separate oil using centrifugal forces

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

leverage the mass inertia of the oil droplets and aerosol

Methodology Applied
Scientific EffectMass inertia: Inertia

Implementation Method 3

the second separator comprises a mist separator or a mesh separator, including a knitted filter material

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 4

leverage the mass inertia of the oil droplets and aerosol, as well as the tendency of smaller droplets to combine into larger particles

Methodology Applied
Scientific EffectCoalescence: Coagulation

Data Source

PatentEP4711618A1Compressor for vehicles with enhanced oil separation efficiency
Publication Date: 2026.03.18 KB INTELLECTUAL PROPERTY GMBH & CO KG
  • EP4711618A1 patent drawingFigure 1
  • EP4711618A1 patent drawingFigure 2
  • EP4711618A1 patent drawingFigure 3

AI summary

Rotary vane compressor (100), for an air treatment system of a vehicle, comprising a vane cell (2) for producing compressed gas streams, and a separation unit (200) for separating oil from the compressed gas streams, wherein the separation unit is in fluid communication with the vane cell and is configured to separate oil from the compressed gas stream exiting an outlet (9) of the vane cell, and wherein the separation unit comprises a first separator (204), in particular a centrifugal separator, and a second separator (202), wherein the second separator is positioned downstream of the first separation in the direction of the compressed gas stream.