Scroll Compressor Oil Separation Member Design

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Solution Overview

Problem

In scroll compressors, particularly the lower compression type, there is an issue with oil separation efficiency due to interference between refrigerant and oil flow paths, leading to oil shortage and increased frictional loss, especially at varying motor operation speeds, resulting in reduced reliability and increased noise.

Innovation Solution

The implementation of an oil separation member with a truncated cup shape and a balance weight connected to the rotator, along with a flow passage separation unit, separates refrigerant and oil by centrifugal force and prevents oil from being mixed with refrigerant, ensuring efficient oil collection in a lower space within the casing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the discharge pipe is positioned over the electric motor in lower compression type scroll compressors, then the structure is simplified, but oil separation effectiveness deteriorates due to interference between refrigerant and oil flow paths

Engineering Contradiction:
Improvestructural complexityVSAvoidoil separation effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the flow paths into separate channels: a refrigerant flow passage and an oil flow passage. The refrigerant flows from the compression unit through the electric motor to the discharge pipe, while oil flows from the compression unit through a separate path beneath the electric motor to the oil storage space. This segmentation prevents interference between the two fluids and maintains effective oil separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a flow passage separation unit as an intermediary structure between the refrigerant and oil flow paths. This separation unit acts as a mediator that guides refrigerant through the electric motor while directing oil through a separate channel, preventing mixing and maintaining distinct flow paths throughout the system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If centrifugal force is used for oil separation at high or low speeds, then some oil separation effect is achieved, but dependence on motor speed makes satisfactory separation difficult at intermediate speeds

Engineering Contradiction:
Improvemotor operation speedVSAvoidoil separation consistency
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent replaces the speed-dependent centrifugal separation mechanism with a structure-independent flow passage separation system. Instead of relying on rotational speed to separate oil from refrigerant, the system uses dedicated flow passages and a flow passage separation unit that maintain effective separation across all motor speeds, including intermediate speeds where centrifugal force is insufficient.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If refrigerant and oil flow paths are not separated, then the structure is simpler, but oil collects in the wrong space and is discharged with refrigerant, causing oil shortage

Engineering Contradiction:
Improveflow path configurationVSAvoidoil quantity in compressor
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The patent segments the flow paths into distinct refrigerant and oil channels. The refrigerant flow passage allows refrigerant to pass through the electric motor to the discharge, while the oil flow passage directs oil beneath the electric motor to the oil storage space. This segmentation ensures oil accumulates in the correct location and prevents oil discharge with refrigerant.

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

This configuration enhances oil separation effectiveness across all operation speeds, reduces oil shortage, and minimizes frictional loss and noise, thereby improving the reliability and efficiency of the compressor.

Implementation Method 1

an oil separation member that is provided above the electric motor and that increases inertia of oil and thus separates oil from refrigerant by increased inertia

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

an oil separation member that is provided above the electric motor and that increases inertia of oil and thus separates oil from refrigerant by increased inertia

Methodology Applied
Scientific EffectInertia: Inertia

Data Source

PatentEP3401544B1Scroll compressor with oil separation
Publication Date: 2022.08.24 LG ELECTRONICS INC
  • EP3401544B1 patent drawingFigure 1
  • EP3401544B1 patent drawingFigure 2
  • EP3401544B1 patent drawingFigure 3

AI summary

Provided a scroll compressor including: a casing, an internal space in which is sealed; a drive motor that is configured with a stator which is located in the internal space, and a rotator which rotates within the stator, and that has an internal flow passage and an external flow passage that passes through the drive motor itself; a rotation shaft that is connected to the rotator of the drive motor; a compression unit that includes a first scroll which is provided below the drive motor, and a second scroll which is engaged with the first scroll; a discharge pipe that communicates with an upper space of the internal space, which is formed above the drive motor; and an oil separation member that is provided between the drive motor and the discharge pipe, and from whose upper surface a space is formed to a predetermined depth.