Horizontal Compressor Rib Design for Oil Separation and Lubrication

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Solution Overview

Problem

In horizontal compressors, oil from the reservoir easily mixes with refrigerant and is discharged, leading to insufficient lubrication due to the horizontal orientation, which increases the amount of oil discharged and potentially causes lubrication failures.

Innovation Solution

A rib is strategically placed in the suction pipe's flow passage to reduce the flow rate of refrigerant and separate oil droplets from the refrigerant gas, preventing them from entering the compression chamber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the compressor is set horizontally to save installation space, then the installation flexibility is improved, but the oil separation performance deteriorates due to oil easily mixing with refrigerant and being discharged

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidoil separation performance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The suction passage is divided into multiple sections with ribs creating segmented flow paths. The refrigerant flow is split into multiple streams that pass between adjacent ribs, increasing the separation distance and time between oil droplets and preventing them from reaching the compression chamber.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The problem of oil separation in horizontal orientation is solved by introducing a vertical dimension through upwardly inclined ribs. The ribs create an upward flow component that opposes gravity's effect on oil droplets, utilizing vertical motion to separate oil from refrigerant in the horizontal compressor configuration.

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

2Reliability

If the rib is made longer to improve oil separation, then the oil separation performance is improved, but the refrigerant flow resistance increases

Engineering Contradiction:
Improveoil separation performanceVSAvoidrefrigerant flow resistance
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

Instead of using excessively long ribs that would create high flow resistance, the invention uses a plurality of ribs with optimized lengths that provide sufficient separation performance. The multiple shorter ribs achieve the same separation effect as fewer longer ribs while minimizing flow resistance and energy loss.

Inventive Principle:
Principle #16Partial or excessive action

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 effectively reduces the amount of oil discharged from the compressor, ensuring adequate lubrication and preventing oil shortages, even when the compressor is oriented horizontally.

Implementation Method 1

flowing refrigerant gas strikes the rib, thereby reducing the flow rate of the refrigerant gas

Methodology Applied
Scientific EffectFlow resistance: Drag

Implementation Method 2

even if oil flies off from the oil reservoir, the refrigerant along with the oil contained therein strikes the rib, whereby the oil can be separated from the refrigerant gas

Methodology Applied
Scientific EffectGravitational separation: Gravitation

Data Source

PatentEP3572672B1Compressor and refrigeration cycle system
Publication Date: 2023.08.23 MITSUBISHI ELECTRIC CORP

AI summary

A compressor includes a container provided with an oil reservoir which is provided at a bottom portion of the container to allow oil to be collected in the oil reservoir. The container is provided such that a rotary shaft is inclined relative to the direction of gravity or to be laid horizontal. In the container, an electric motor mechanism, the rotary shaft, a compression mechanism and a frame which fixes the compression mechanism to the container are provided. To the container, a suction pipe is connected to cause refrigerant to flow into space between the frame and the electric motor mechanism. In the frame, a suction port is formed to cause the refrigerant having flowed into the space to flow into the compression mechanism, and each of the suction portion and a connection port of the suction pipe, which connects with the container is located at a position which is higher than or the same as the level of the rotary shaft as seen in a rotation axial direction. A rib is formed in a first flow passage which extends downwards in the direction of gravity from the connection port, extends through an area located above the oil reservoir, and reaches the suction port.