Compressor Oil Return Guide Structure for Swirl Oil Loss

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Solution Overview

Problem

The existing compressors suffer from increased oil loss due to the formation of an oil film on the side surfaces of flow path members, which is scattered back into the gas refrigerant, leading to inefficiency.

Innovation Solution

Incorporation of a blocking part on the oil return guide, gas guide, and lower frame components to prevent the oil film from scattering back into the refrigerant by redirecting the flow and collecting the oil into the reservoir.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If a compressor is disassembled for maintenance or replacement of the driving device, then the driving device can be accessed, but the refrigerant remaining in the compressor cannot be discharged and causes environmental pollution

Engineering Contradiction:
Improveaccessibility of driving deviceVSAvoidrefrigerant discharge pollution
Core Design Contradiction:
Ease of repairVSObject-affected harmful factors

Solution Approach 1:

A discharge valve is introduced as an intermediary component between the refrigerant and the external environment. This valve remains closed during normal operation and maintenance activities, preventing refrigerant discharge. Only when specifically opened does it allow controlled refrigerant discharge, thus mediating between the need for maintenance access and the need to prevent pollution.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The discharge valve is pre-positioned and integrated into the compressor structure before maintenance is needed. This preliminary arrangement ensures that the refrigerant discharge path is already controlled and ready, preventing the need for ad-hoc discharge procedures that could lead to pollution during maintenance operations.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the suction port and discharge port are disposed of in directions away from each other, then liquid hammer is prevented, but the overall structure becomes larger

Engineering Contradiction:
Improveprevention of liquid hammerVSAvoidcompressor size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The suction port and discharge port are arranged in different spatial dimensions and orientations rather than simply opposing each other in a straight line. The discharge port is positioned at the front end of the cylinder and inclined relative to the cylinder axis, while the suction port is at the rear end. This three-dimensional arrangement prevents liquid hammer by avoiding direct opposition while minimizing the increase in overall compressor volume through optimized spatial configuration.

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

3Productivity

If a large number of spare parts are kept for maintenance, then maintenance can be performed quickly, but the cost increases

Engineering Contradiction:
Improvemaintenance speedVSAvoidspare parts inventory
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The discharge valve is integrated as a standard component within the compressor assembly rather than being a separate spare part. This merging of the discharge valve into the main compressor structure means it is replaced as part of the compressor unit itself, eliminating the need to maintain separate inventory of discharge valves and reducing overall spare parts requirements while maintaining quick maintenance capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The discharge valve serves multiple functions: it controls refrigerant discharge during maintenance, prevents refrigerant leakage during normal operation, and can be integrated with the drive mechanism. This multi-functionality reduces the need for dedicated spare parts for each function, as a single component handles multiple roles.

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

Data Source

PatentEP4400723B1Compressor and freezer device
Publication Date: 2026.04.29 DAIKIN INDUSTRIES LTD
  • EP4400723B1 patent drawingFigure 1
  • EP4400723B1 patent drawingFigure 2
  • EP4400723B1 patent drawingFigure 3

AI summary

A compressor includes: a casing (12); an electric motor (60) housed in the casing (12); and a compression mechanism (70) driven by the electric motor (60). A gas refrigerant discharged from the compression mechanism (70) forms a swirling flow in an internal space (S) of the casing (12). A component (11), such as an oil return guide (90), which has a facing surface (11a) that faces against the swirling flow of the gas refrigerant is arranged in the internal space (S) of the casing (12). The component (11) includes a blocking part (120) configured to block a flow of oil (OL) deposited on the facing surface (11a) due to a collision of the swirling flow.