Oil separator

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Solution Overview

Problem

Conventional air conditioning systems face inefficiencies due to high oil carryover and pressure drops in oil/gas separators, which are heavy, costly, and limited by gas velocity, affecting system performance and installation convenience.

Innovation Solution

A centrifugal oil/gas separator with a smaller diameter centrifuging cylinder made from lightweight materials like copper or aluminum, featuring a duct with bends for initial separation and an impingement stage to prevent re-entrainment, allowing for efficient oil separation with reduced pressure loss and lower oil carryover.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional iron or metallic centrifugal cylinder is used, then oil separation effectiveness is improved, but weight increases making installation inconvenient

Engineering Contradiction:
Improveoil separation effectivenessVSAvoidseparator weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent changes the material parameter from heavy iron/metal to lightweight materials such as plastic or composite materials while maintaining the centrifugal separation functionality. This allows the separator to achieve adequate oil separation effectiveness without the excessive weight of traditional metallic construction.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If gas velocity is increased to improve oil separation, then separation effectiveness improves, but pressure drop increases reducing system efficiency

Engineering Contradiction:
Improveoil separation effectivenessVSAvoidpressure drop
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent introduces a vertical dimension to the separation process by using a centrifugal cylinder where oil particles are thrown outward to the wall and then drain downward to a reservoir. This vertical drainage path allows effective separation without requiring high horizontal gas velocities, thereby reducing pressure drop while maintaining separation effectiveness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If a single large separator is used, then oil separation capacity is improved, but cost and complexity increase

Engineering Contradiction:
Improveoil separation capacityVSAvoidseparator complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the separation system into functional segments: a centrifugal cylinder for primary separation, a drainage system for oil collection, and a reservoir for oil accumulation. This segmentation allows for simpler manufacturing and assembly compared to a single large complex separator, while maintaining adequate separation capacity for the compressor.

Inventive Principle:
Principle #1Segmentation

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 solution achieves low oil carryover levels of 1.5% and improves efficiency per unit size, simplifies manufacturing, and operates effectively across various conditions, while being more cost-effective and suitable for rooftop installations.

Implementation Method 1

The first separation phase is created using a straight length 31 of the duct 20 combined with a bend section 32 coupling the straight length 31 into the cylinder 22. The partly separated gas and oil pass into a second separation phase which is an impingement stage, constructed to prevent re-entrainment. This phase incorporates the centrifuging cylinder 22 designed to further separate the oil 23 from the gas stream 26

Methodology Applied
Scientific EffectCentrifugal effect: Centrifugal Force

Data Source

PatentEP3685106B1Oil separator
Publication Date: 2024.10.30 DAIKIN INDUSTRIES LTD
  • EP3685106B1 patent drawingFigure 1~2
  • EP3685106B1 patent drawingFigure 3
  • EP3685106B1 patent drawingFigure 4

AI summary

An oil/gas separator comprises a duct 20 having an inlet 13 for receiving an oil/gas mixture, the duct having an inner surface extending at least partially in a horizontaldirection and providing a bend 32 or series of bends. The duct 20 provides at least partial separation of the oil/gas mixture, in use, by both gravitational and centrifugal oil collection onto the inner surface. The duct is arranged to deliver gas and collected oil into a centrifuging cylinder 22 providing an internal impingement surface, an upper gas outlet 30, and a lower oil outlet 24. The cylinder 22 has an internal diameter of less than 180 mm. Thus, the oil separator of is, in effect, formed by the pipework that is required to recirculate refrigerant.