Two-Stage Reciprocating Compressor Axial Fan Placement

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Solution Overview

Problem

Conventional two-stage reciprocating compressors face inefficiencies in cooling due to the positioning of cooling fans and intercoolers, which disrupt airflow and hinder effective heat dissipation, leading to suboptimal temperature management during operation.

Innovation Solution

The compressor design includes a fan positioned between the intercooler and the rear end surface of the motor case in the axial direction, with ribs on the motor case to enhance airflow and heat dissipation, improving the cooling efficiency by directing cooling wind through the intercooler and dissipating heat generated by the stator coil.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the cooling fan is positioned behind the motor with respect to the motor axis, then the structure is compact, but the cooling efficiency is reduced due to disrupted airflow

Engineering Contradiction:
Improvecompressor volumeVSAvoidcooling efficiency
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The fan is repositioned from a rearward axial position to a lateral position on the motor case, changing the airflow direction from behind the motor to the side. This dimensional repositioning allows the fan to draw air from the front and discharge it through the intercooler on the lateral side, improving cooling efficiency while maintaining compact structure.

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

2Temperature

If the fan is positioned to provide cooling airflow, then cooling performance is improved, but the airflow may disrupt the compression process

Engineering Contradiction:
Improvecooling performanceVSAvoidcompression efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The motor case is segmented into distinct airflow paths: one for compression air intake and another for cooling air intake. The cooling fan draws air through a dedicated opening on the motor case, separate from the compression chamber, allowing cooling airflow and compression airflow to be spatially separated and not interfere with each other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The intercooler acts as an intermediary component that receives compressed air from the compressor and cools it using airflow generated by the fan. This intermediary arrangement allows the fan to focus solely on generating cooling airflow without directly interfering with the compression process, as the intercooler mediates between the compressed air and the cooling air.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If ribs are added to the motor case to enhance heat dissipation, then heat dissipation efficiency is improved, but the device complexity increases

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidcase structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The ribs are integrated directly into the motor case structure as a single piece, combining the heat dissipation function with the existing case geometry. This merging approach avoids adding separate heat dissipation components and maintains structural simplicity while improving thermal performance.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances cooling performance by ensuring effective airflow to the intercooler and efficient heat dissipation, leading to better temperature management and operational efficiency.

Implementation Method 1

a fan connected to the output shaft, where the fan is interposed between the end surface of the case and the intercooler in the axial direction

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

a plurality of ribs are provided on an outer surface of the case and extend in the axial direction

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

electric motors are driven by a current applied thereto, and the applied current results in generation of Joule's heat. This raises the temperature of the electric motors

Methodology Applied
Scientific EffectJoule Heating: Joule Heating

Implementation Method 4

an intercooler for cooling compressed air discharged from the low-pressure compressor element

Methodology Applied
Scientific EffectHeat Exchanger: Heat Exchanger

Data Source

PatentEP3904684B1Two-stage reciprocating compressor
Publication Date: 2024.02.14 NABTESCO AUTOMOTIVE CORP
  • EP3904684B1 patent drawingFigure 1
  • EP3904684B1 patent drawingFigure 2
  • EP3904684B1 patent drawingFigure 3

AI summary

A reciprocating compressor relating to one aspect of the present invention includes a rotatable drive source accommodated within a case, an output shaft for outputting rotation provided from the rotatable drive source, where the output shaft extends in an axial direction such that one end thereof protrudes through an end surface of the case, a low-pressure compressor element for compressing air, where the low-pressure compressor element is powered by a rotational drive force provided from the output shaft, an intercooler for cooling compressed air discharged from the low-pressure compressor element, a high-pressure compressor element for further compressing the compressed air that has been cooled by the intercooler, where the high-pressure compressor element is powered by a rotational drive force provided from the motor output shaft, and a fan connected to the output shaft, where the fan is interposed between the end surface of the housing and the intercooler in the axial direction.