Rotary Compressor Discharge Opening Layout for Low Dead Volume

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional rotary compressors experience efficiency losses due to dead volume creation during refrigerant discharge, particularly due to the presence of a discharge guide groove which acts as a dead volume, and moving the discharge opening to minimize this volume can compromise bearing installation and reliability.

Innovation Solution

The compressor features a discharge opening formed parallel to the shaft direction with a non-perfect circle shape, overlapping at least a portion of the compression space's cross-sectional area, and a width in the short-axis direction not exceeding 1.1 times the sealing thickness of the piston, allowing for efficient refrigerant discharge without a discharge guide groove.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a discharge guide groove is added to guide refrigerant to the discharge opening, then refrigerant discharge is improved, but dead volume increases and compressor efficiency decreases

Engineering Contradiction:
Improverefrigerant dischargeVSAvoidcompressor efficiency
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The invention removes the discharge guide groove from the compressor structure entirely. By extracting this unnecessary component, the patent eliminates the dead volume it created while maintaining effective refrigerant discharge through the optimized discharge opening configuration.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The discharge opening is repositioned and reoriented to extend in the axial direction of the compressor shaft rather than relying on a separate guide groove structure. This dimensional change allows the discharge opening itself to perform the guiding function that previously required a separate groove component.

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

2Volume of stationary object

If the discharge opening is moved closer to the compression space to reduce dead volume, then discharge dead volume decreases, but bearing installation space is compromised and reliability decreases

Engineering Contradiction:
Improvedischarge dead volumeVSAvoidbearing reliability
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The discharge opening is reoriented to extend in the axial direction rather than radially, allowing it to reach into the compression space without compromising the radial space needed for bearing installation. This dimensional reorientation resolves the spatial conflict between discharge opening positioning and bearing accommodation.

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

Solution Approach 2:

The discharge opening is segmented into multiple portions (first discharge opening portion and second discharge opening portion) that extend in different directions, allowing it to access the compression space effectively while maintaining clear separation from the bearing installation areas.

Inventive Principle:
Principle #1Segmentation

3Productivity

If the discharge opening area is increased to reduce discharge resistance, then refrigerant discharge efficiency improves, but dead volume increases and compressor efficiency decreases

Engineering Contradiction:
Improverefrigerant discharge efficiencyVSAvoidcompressor efficiency
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The discharge opening utilizes the axial dimension by extending in the shaft direction, providing a large discharge area without increasing radial or axial dead volume. This dimensional approach allows high discharge efficiency while minimizing the volume of space occupied by the discharge structure itself.

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

Data Source

PatentEP2960514B1compressor
Publication Date: 2016.11.30 LG ELECTRONICS INC
  • EP2960514B1 patent drawingFigure 1
  • EP2960514B1 patent drawingFigure 2~3
  • EP2960514B1 patent drawingFigure 4

AI summary

A compressor includes: a compression space (S) with an annular shape comprising an inner circumferential surface and an outer circumferential surface; and a discharge opening (111) communicated with the compression space (S), to discharge a refrigerant compressed in the compression space, wherein a first portion (A B ) of a cross-sectional area of the discharge opening (111) overlaps a portion of a cross-sectional area of the compression space, a second portion (A C ) of the cross-sectional area of the discharge opening (111) does not overlap the cross-sectional area of the discharge opening, and the ratio of the non-overlapping second portion of the cross-sectional area of the discharge opening to the entire cross-sectional area of the discharge opening is 0.1 or less. With such a configuration, a dead volume generated in the compression space can be reduced, and thus compressor efficiency can be enhanced.