Rotary Compressor Segmented Housing for Natural Refrigerants

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Solution Overview

Problem

Rotary compressors face challenges with high internal pressures due to the use of natural refrigerants like CO2 and HC refrigerants, which require thick housing walls and limit refrigerant amounts, and lubricating oils' solubility in these gases reduces viscosity, leading to lubrication issues and efficiency decreases.

Innovation Solution

A rotatory compressor design with a hermetically sealed housing containing lubricating oil and an electric motor, featuring an air cylinder with a sliding vane mechanism and eccentric shaft, where the internal pressure is equal to suction pressure, allowing efficient lubrication of sliding vanes and controlled oil supply through an oil separator, reducing oil amounts and preventing efficiency decreases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If high-pressure housing is used to withstand CO2 operation pressure, then the compressor can operate with natural refrigerants, but the housing wall thickness must be more than 7 mm causing significant production problems and cost increase

Engineering Contradiction:
Improveability to use natural refrigerantsVSAvoidhousing production difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The housing is divided into two distinct pressure zones: a low-pressure outer housing (5 MPa or less) and a high-pressure inner compression chamber. This segmentation allows the outer housing to use thin walls for easy manufacturing while the inner chamber withstands high CO2 pressures during compression.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A partition structure acts as an intermediary between the low-pressure outer housing and the high-pressure compression chamber. This partition isolates the high-pressure zone during compression while allowing the outer housing to maintain low pressure, enabling both high-pressure operation and easy manufacturing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If high internal pressure housing is used, then energy efficiency is improved, but the housing wall thickness increases causing cost increase

Engineering Contradiction:
Improveenergy efficiencyVSAvoidhousing production cost
Core Design Contradiction:
Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The housing structure is segmented into low-pressure outer shell and high-pressure inner chamber, allowing the outer housing to use thin walls reducing material cost while the inner chamber maintains high pressure for energy efficiency.

Inventive Principle:
Principle #1Segmentation

3Productivity

If HC refrigerants with strong solubility in lubricating oil are used, then the refrigeration effect is improved, but the viscosity of oils is significantly reduced causing lubrication issues

Engineering Contradiction:
Improverefrigeration effectVSAvoidlubrication reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The harmful effect of oil viscosity reduction is eliminated by extracting the oil from the high-pressure compression chamber before the refrigerant is discharged. The oil separator removes lubricating oil from the compressed refrigerant, preventing it from mixing with the system oil and causing viscosity reduction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

An oil separator acts as an intermediary between the compression chamber and the discharge line, separating oil from the compressed refrigerant and preventing oil viscosity degradation while maintaining effective refrigeration.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If the amount of refrigerant sealed in the system is limited due to flammability, then safety is improved, but the refrigeration capacity is reduced

Engineering Contradiction:
Improveflammability safetyVSAvoidrefrigeration capacity
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system is segmented into a low-pressure outer housing containing most of the refrigerant volume and a high-pressure inner compression chamber. This allows the majority of refrigerant to be contained in the low-pressure outer housing where it does not pose flammability risks, while maintaining sufficient refrigeration capacity.

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

The design ensures reliable lubrication of sliding vanes, maintains compressor efficiency, and allows for a low-pressure housing with reduced refrigerant and oil usage, enhancing the reliability and performance of the compressor.

Implementation Method 1

a sliding vane chamber (12) connected with the first bearing flange (25a) and the second bearing flange (30a) respectively... the sliding vane chamber (12) receives the sliding vane (20)... a back force being high enough to beat a pressure in a second stage compression chamber is produced

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

An exhaust muffler (32) is within one of the first bearing (25) and the second bearing (30)... The exhaust muffler (32) is communicated with the sliding vane chamber (12)

Methodology Applied
Scientific EffectGas flow through communication passages:

Implementation Method 3

a piston (24) disposed within the compressing chamber (13); an eccentric shaft (16) adapted to revolute the piston (24)

Methodology Applied
Scientific EffectEccentric rotation mechanism: Eccentric

Implementation Method 4

a sliding vane (20) disposed in the sliding vane chamber (12) and adapted to reciprocate synchronously with the piston (24)... the compressing chamber (13) capable of being communicated with the exhaust muffler (32)

Methodology Applied
Scientific EffectReciprocating compression: Compression

Data Source

PatentEP2927499B1Rotation type compressor and refrigeration cycle apparatus
Publication Date: 2020.04.29 GUANGDONG MEIZHI COMPRESSOR
  • EP2927499B1 patent drawingFigure 1~2
  • EP2927499B1 patent drawingFigure 3~4
  • EP2927499B1 patent drawingFigure 5~6

AI summary

A rotatory compressor and a refrigerating cycle device are provided. The rotatory compressor includes a lubricating oil in an interior of a hermetically sealed housing, and an electric motor and a rotatory compressing mechanism disposed in the housing. An internal pressure of the housing is substantially equal to a suction pressure of the compressing mechanism. The compressing mechanism includes a first bearing and a second bearing at least one of which includes an exhaust muffler. A refrigerant of the exhaust muffler flows through the sliding vane chamber and is discharged from an exhaust pipe of the compressing mechanism.