Open Refrigerant Compressor Seal Lubrication

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Solution Overview

Problem

Open-type refrigerant compressors face issues with insufficient lubrication of seal members at low load operations, leading to potential wear and leakage due to inadequate supply of refrigerant gas and lubricant.

Innovation Solution

An open-type refrigerant compressor design that includes a refrigerant gas distribution system, where the refrigerant gas introduced from the suction port is distributed such that a greater amount flows to a refrigerant supply passage to lubricate the seal member, rather than directly to the compression mechanism, ensuring sufficient lubrication and preventing wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If refrigerant gas is distributed equally to the compression mechanism and seal member, then the compression mechanism receives sufficient refrigerant for operation, but the seal member does not receive adequate lubricant supply especially at low load operations

Engineering Contradiction:
Improveseal member lubrication reliabilityVSAvoidrefrigerant gas compression efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by creating different refrigerant gas distribution ratios for different parts of the system. Specifically, the refrigerant gas distribution portion directs a greater proportion of refrigerant gas to the seal member (first refrigerant supply passage) compared to the compression mechanism (second refrigerant supply passage). This localized differentiation ensures that the seal member receives adequate lubricant supply for reliable operation, while the compression mechanism still receives sufficient refrigerant for its compression function.

Inventive Principle:
Principle #3Local quality

2Reliability

If more refrigerant gas is directed to the seal member for lubrication, then the seal member is adequately lubricated, but less refrigerant gas is available for the compression mechanism

Engineering Contradiction:
Improveseal member lubricationVSAvoidrefrigerant gas amount for compression
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies parameter changes by adjusting the distribution ratio parameter of refrigerant gas flow. The refrigerant gas distribution portion is designed with specific flow resistance characteristics that naturally allocate a greater proportion of refrigerant gas to the seal member while maintaining adequate supply to the compression mechanism. This parameter optimization ensures both the seal member receives sufficient lubricant and the compression mechanism receives enough refrigerant gas for its operation.

Inventive Principle:
Principle #35Parameter changes

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

This configuration ensures reliable lubrication of the seal member, preventing wear and maintaining the integrity of the seal, even during low load operations by prioritizing refrigerant gas distribution to the seal member, thereby enhancing the lubrication state and reducing leakage risks.

Implementation Method 1

a distribution ratio of the refrigerant gas distributed by the refrigerant gas distribution portion is set such that an amount distributed to the refrigerant supply passage side is greater than an amount distributed to the compression mechanism side

Methodology Applied
Scientific EffectFluid flow distribution:

Implementation Method 2

a lip seal (an oil seal having a lip) is provided in the protrusion portion of the drive shaft, that is, the shaft hole of the housing, and thus, a refrigerant gas inside the housing is prevented from leaking to the outside

Methodology Applied
Scientific EffectSealing:

Implementation Method 3

The lip seal is lubricated by a lubricant mixed with the refrigerant gas

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3418569B1Open-type refrigerant compressor
Publication Date: 2020.03.25 MITSUBISHI HEAVY IND THERMAL SYST
  • EP3418569B1 patent drawingFigure 1
  • EP3418569B1 patent drawingFigure 2
  • EP3418569B1 patent drawingFigure 3

AI summary

An open-type refrigerant compressor (1) equipped with: a housing (2); an intake port (3); a compression mechanism (4) that compresses a refrigerant gas containing lubricating oil in the interior of the housing (2); a drive shaft (5) for driving the compression mechanism; a seal member (9) that is provided in a shaft hole (8) through which the drive shaft (5) protrudes to the outside from the housing (2), and that prevents refrigerant gas from leaking to the outside from the interior of the housing (2); a refrigerant supply passage (35) connecting the interior of the housing (2) and the seal member (9); and a refrigerant gas distribution unit (22) that distributes refrigerant gas, which has been introduced into the interior of the housing (2) from the intake port (3), to the refrigerant supply passage (35) side and the compression mechanism (4) side. The refrigerant gas distribution ratio of the refrigerant gas distributed by the refrigerant gas distribution unit (22) is set such that the amount distributed to the refrigerant supply passage (35) side is greater than the amount distributed to the compression mechanism (4) side.