Compressor Oil Feeding Path for Scroll-Rotary Lubrication

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In compressors with rotary and scroll type compression mechanisms, the lubricating oil level in the oil reservoir can decrease, leading to inadequate lubrication of the blade, increased friction, and reduced mechanical efficiency, especially when using CO2 as a refrigerant gas, which increases the dissolution of lubricating oil and affects the oil level height.

Innovation Solution

A compressor design that feeds lubricating oil from a lubrication pump to the high stage-side scroll type compression mechanism, which then directs the oil to the blade through a penetrating hole, ensuring lubrication even if the oil level lowers, and includes an oil feeding path that minimizes oil dissolution in refrigerant gas and prevents excess oil circulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If CO2 is used as refrigerant gas, then environmental friendliness is improved, but the dissolution amount of lubricating oil increases causing oil level to change depending on operating conditions

Engineering Contradiction:
Improveenvironmental impactVSAvoidlubrication reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces an oil level adjustment mechanism that acts as an intermediary between the oil reservoir and the compression mechanism. This mechanism dynamically adjusts the oil level to compensate for the increased oil dissolution caused by CO2 refrigerant, ensuring reliable lubrication while maintaining environmental benefits of CO2 usage.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the oil level parameter dynamically based on operating conditions. By adjusting the oil level in response to CO2 refrigerant circulation, the system compensates for variable oil dissolution rates, maintaining stable lubrication conditions despite changes in refrigerant type and operating parameters.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If inverter is used for rotational speed control, then energy saving is improved, but the height of oil level changes depending on rotational speed

Engineering Contradiction:
Improveenergy consumptionVSAvoidlubrication stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements a dynamic oil level adjustment system that adapts to varying rotational speeds controlled by the inverter. As the inverter changes motor speed to optimize energy consumption, the oil level adjustment mechanism dynamically compensates for resulting oil level fluctuations, maintaining stable lubrication across the full speed range.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms that monitor oil level and rotational speed, using this information to adjust oil level in real-time. This feedback loop ensures that lubrication stability is maintained despite the variable operating conditions created by inverter-controlled speed variation.

Inventive Principle:
Principle #23Feedback

3Productivity

If oil level becomes lower than the cylinder, then mechanical efficiency decreases due to increased friction, but adding more oil increases oil dissolution in refrigerant gas

Engineering Contradiction:
Improvemechanical efficiencyVSAvoidlubricating oil dissolution
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent optimizes the oil level parameter to a specific range that balances two opposing requirements: maintaining sufficient oil level to prevent blade friction and ensure mechanical efficiency, while limiting excessive oil level that would increase oil dissolution in CO2 refrigerant. This precise parameter control resolves the contradiction between lubrication adequacy and oil loss.

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

Ensures consistent lubrication of the blade, maintaining mechanical efficiency and reliability by stabilizing the lubricating oil supply, even at low oil levels, and reducing the impact of refrigerant gas on oil level changes, thereby preventing decreased compressing efficiency.

Implementation Method 1

a lubrication pump (60) which draws up the lubricating oil (27) and feeds it to the scroll type compression mechanism (4)

Methodology Applied
Scientific EffectPumping: Pump

Implementation Method 2

If CO 2 in a supercritical pressure state is used, the dissolution amount of lubricating oil increases, so that the height of oil level is liable to change depending on the operating condition

Methodology Applied
Scientific EffectDissolution: Solvation

Data Source

PatentEP2050966B1Compressor
Publication Date: 2017.04.26 MITSUBISHI HEAVY IND THERMAL SYST
  • EP2050966B1 patent drawingFigure 1
  • EP2050966B1 patent drawingFigure 2
  • EP2050966B1 patent drawingFigure 3

AI summary

A compressor (1) including a low stage-side rotary type compression mechanism (3) having a rotor (34), and a blade (38) reciprocating with the rotation of the rotor (34) while the tip end thereof is in contact with the rotor (34); a high stage-side scroll type compression mechanism (4) for sucking and compressing refrigerant gas compressed by the low stage-side rotary type compression mechanism (3); a positive displacement lubrication pump (60) for feeding lubricating oil (27) to the high stage-side scroll type compression mechanism (4); and an oil feeding path for feeding the lubricating oil (27), which is fed to the high stage-side scroll type compression mechanism (4), toward the blade (38) of the low stage-side rotary type compression mechanism (3).