Compressor Centrifugation Space Design to Reduce Oil Content Rate

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Solution Overview

Problem

Compressors, particularly the upper compression type, suffer from high oil content rates due to lubricant oil being discharged with refrigerant, leading to reduced cooling efficiency and the need for separate oil recovery apparatuses, while lower compression type compressors also have non-negligible oil content rates, necessitating a solution to reduce oil content effectively.

Innovation Solution

The compressor design utilizes a discharge space as a centrifugation space, with a rotating member and guide to enhance centrifugal separation, and modifications to the shell shape and terminal placement to minimize flow resistance, achieving significant oil content reduction by expanding the centrifugation space and removing obstructive factors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the compressor uses a conventional discharge space design, then the structure is simple, but the oil content rate in discharged refrigerant remains high

Engineering Contradiction:
Improveoil content rateVSAvoiddischarge space structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The discharge space is segmented into multiple functional zones: a centrifugation zone with a rotating member for oil-refrigerant separation, and a discharge zone for refrigerant outlet. This segmentation allows the discharge space to perform both centrifugal separation and refrigerant discharge functions simultaneously, reducing oil content rate without requiring separate apparatuses

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The discharge space is designed to serve multiple functions: it acts as both the centrifugation space for oil separation and the discharge space for refrigerant outlet. The rotating member within the discharge space generates centrifugal force for separation while the space itself facilitates refrigerant discharge, eliminating the need for separate oil recovery apparatus

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Quantity of substance

If the compressor uses a lower compression type design with centrifugal separation, then the oil content rate is reduced, but separate oil recovery apparatus is still needed

Engineering Contradiction:
Improveoil content rateVSAvoidapparatus configuration
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The centrifugal separation function and refrigerant discharge function are merged into a single integrated discharge space design. The rotating member is positioned within the discharge space, and both oil separation and refrigerant discharge occur in the same space, eliminating the need for separate oil recovery apparatus

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The discharge space itself performs the oil separation function through the rotating member's centrifugal action, without requiring external or separate oil recovery apparatus. The system uses its own discharge space structure to achieve oil-refrigerant separation

Inventive Principle:
Principle #25Self-service

3Productivity

If the discharge pipe is positioned centrally, then the structure is simple, but flow resistance increases and centrifugation efficiency decreases

Engineering Contradiction:
Improvecentrifugation efficiencyVSAvoiddischarge pipe configuration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The discharge pipe is positioned asymmetrically at the periphery of the centrifugation space rather than at the center. This asymmetric positioning allows the discharge pipe to be located in a region where refrigerant concentration is higher after centrifugal separation, improving centrifugation efficiency and reducing flow resistance

Inventive Principle:
Principle #4Asymmetry

4Productivity

If the compressor operates at high speed, then productivity increases, but oil content rate in discharged refrigerant increases

Engineering Contradiction:
Improvecompression speedVSAvoidoil content rate
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

A rotating member is introduced into the discharge space to dynamically generate centrifugal force during compressor operation. This dynamic centrifugal action separates oil from refrigerant in real-time during high-speed operation, allowing the compressor to maintain high productivity while keeping oil content rate low

Inventive Principle:
Principle #15Dynamics

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 effectively reduces oil content rates to less than 0.01 weight percent, eliminating the need for separate oil recovery apparatuses and improving compressor efficiency, while maintaining minimal changes to the existing configuration.

Implementation Method 1

Rotational flow may be generated in the discharge space by a rotor and a rotation shaft of the driving motor. That is, the discharge space may be referred to as a centrifugation space. The rotational flow is generated around a center portion of the discharge space, that is, a center portion of the centrifugation space. Thus, centrifugation of the refrigerant and the lubricant oil may occur by such rotational flow.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

A density of the lubricant oil is significantly higher than that of the refrigerant. Therefore, the lubricant oil may be gathered to an outer portion of the discharge space, the refrigerant may be gathered to a center of the discharge space by the centrifugation

Methodology Applied
Scientific EffectDensity gradient separation: Density Gradient

Data Source

PatentEP3650699B1compressor
Publication Date: 2024.03.06 LG ELECTRONICS INC
  • EP3650699B1 patent drawingFigure 1
  • EP3650699B1 patent drawingFigure 2
  • EP3650699B1 patent drawingFigure 3

AI summary

The present disclosure relates to a compressor, specifically, to a compressor that may effectively separate lubricant oil and compressed refrigerant within the compressor. A compressor including a case, a driving motor including a stator mounted inside the case and a rotor disposed radially inward of the stator and rotatable, a centrifugation space defined inside the case by one side (downstream side) of the driving motor and the case, wherein centrifugation of compressed refrigerant and lubricant oil is performed in the centrifugation space, a discharge pipe passing through the case and defining a refrigerant inlet hole, a rotation shaft coupled to the rotor to rotate, a compressing portion defined at the other side (upstream side) of the driving motor, wherein the refrigerant is compressed by rotation of the rotation shaft, and a rotating member disposed to spread a rotary power of the rotor to the centrifugation space, thereby providing a centrifugal force to the refrigerant and the oil, wherein the rotating member is disposed at one side (downstream side) of the rotor to rotate integrally with the rotor may be provided.