Scroll compressor

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Solution Overview

Problem

High-pressure scroll compressors, particularly bottom-compression type, face issues with oil and refrigerant backflow into the suction pipe when stopped, leading to increased suction loss and potential oil shortages, due to the direct connection of the refrigerant suction pipe to the compression unit and the proximity of the oil storage space.

Innovation Solution

A scroll compressor design incorporating a non-return valve within the suction passage that connects the refrigerant suction pipe to the compression unit, allowing the valve to operate in an axial direction and be installed without extending the compressor length, effectively blocking backflow by using its own weight and simplifying the structure for improved responsiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the refrigerant suction pipe is directly connected to the compression unit in a high-pressure scroll compressor, then the compression ratio and efficiency are improved, but oil and refrigerant backflow into the suction pipe occurs when stopped

Engineering Contradiction:

Improvecompression ratioVSAvoidbackflow prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A non-return valve is introduced as an intermediary component between the compression unit and the suction passage. This valve selectively opens during compression to allow refrigerant flow while closing during stoppage to prevent oil and refrigerant backflow, thus resolving the contradiction between maintaining direct connection for efficiency and preventing backflow for reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the compression unit is located below the motor unit in a bottom-compression type scroll compressor, then the structure is compact, but oil storage space proximity increases backflow risk

Engineering Contradiction:

Improvestructural compactnessVSAvoidbackflow risk

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The non-return valve serves as a protective intermediary that blocks the harmful backflow path from the oil storage space near the compression unit, allowing the bottom-compression compact structure to be maintained while eliminating the backflow hazard

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a check valve is installed in the suction passage, then backflow is prevented, but responsiveness is lowered and a separate elastic member is added

Engineering Contradiction:

Improvebackflow preventionVSAvoidvalve structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The suction passage opening and closing valve utilizes the pressure differential created during compression and stoppage cycles to automatically open and close without requiring a separate elastic member or external actuation mechanism, achieving self-service operation that maintains reliability while reducing structural complexity

Inventive Principle:

Principle #25Self-service

4Productivity

If the suction passage is extended to connect the refrigerant suction pipe and compression unit, then direct connection is achieved, but the compressor length increases

Engineering Contradiction:

Improvecompression efficiencyVSAvoidcompressor length

Core Design Contradiction:

ProductivityVSLength of moving object

Solution Approach 1:

The suction passage is routed through the axial direction of the compressor, utilizing the existing axial space between components rather than extending radially or lengthening the overall compressor structure, thus maintaining compression efficiency without increasing compressor length

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 restricts oil and refrigerant backflow, reducing suction loss and frictional losses, while maintaining efficient operation and reliability by preventing oil leakage and ensuring consistent oil supply to the compression unit.

Implementation Method 1

a suction passage opening and closing valve which is provided inside the suction passage and configured to slide in an axial direction to thereby selectively open or close the suction passage

Methodology Applied

Scientific EffectSliding motion:

Implementation Method 2

A scroll compressor design incorporating a suction passage with a non-return valve that blocks fluid backflow from the compression unit to the refrigerant suction pipe

Methodology Applied

Scientific EffectOne-way flow control: Valve

Implementation Method 3

an oil supply portion to ensure oil is directed to the compression unit without leaking into the suction pipe

Methodology Applied

Scientific EffectFluid direction control:

Data Source

PatentUS20220034557A1Scroll compressor

Publication Date: 2022.02.03 LG ELECTRONICS INC

AI summary

A scroll compressor includes a refrigerant suction pipe coupled to a discharge cover or a fixed scroll through a casing in a radial direction, a suction passage communicating the refrigerant suction pipe with a compression chamber, and a suction passage opening and closing valve disposed inside the suction passage to be slidable in an axial direction so as to selectively open or close the suction passage. Accordingly, when the compressor is stopped, oil or refrigerant in the casing can be restricted quickly so as not to flow back to the refrigerant suction pipe through a compression unit.