Hermetic Compressor Exhaust Muffler Elliptical Cross-Section Design

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Solution Overview

Problem

In reciprocating hermetic compressors, the existing exhaust mufflers face challenges in reducing pressure losses while maintaining a compact size, as increasing dimensions is undesirable due to space limitations, leading to inefficiencies and noise issues.

Innovation Solution

The exhaust muffler is redesigned with a longer cross-sectional length than width, featuring an elliptical, oblong, or rectangular base with rounded corners, increasing its internal volume without altering the compressor's dimensions, thus minimizing pressure fluctuations and enhancing noise attenuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the dimensions of the exhaust muffler are increased to reduce pressure losses, then the pressure loss decreases, but the compressor size increases

Engineering Contradiction:
Improvepressure lossVSAvoidcompressor size
Core Design Contradiction:
Loss of energyVSVolume of moving object

Solution Approach 1:

The exhaust muffler is transformed from a conventional cylindrical shape to an elongated oval cross-section shape. This dimensional change in the cross-sectional geometry allows the internal volume to be increased along the length dimension while keeping the width and height dimensions constrained, thus reducing pressure losses without increasing the overall compressor footprint.

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

Solution Approach 2:

The exhaust muffler employs an asymmetric oval cross-section with the length dimension significantly greater than the width dimension. This asymmetric geometry optimizes the internal volume distribution to reduce pressure losses in the flow direction while maintaining a compact transverse profile that fits within the compressor casing constraints.

Inventive Principle:
Principle #4Asymmetry

2Object-affected harmful factors

If the dimensions of the exhaust muffler are increased to improve noise attenuation, then the noise attenuation improves, but the compressor size increases

Engineering Contradiction:
ImprovenoiseVSAvoidcompressor size
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The noise attenuation capability is enhanced by extending the length dimension of the oval cross-section rather than increasing all dimensions uniformly. This allows the muffler to provide adequate noise attenuation performance while maintaining a compact width and height that prevent interference with the crankshaft and piston rod.

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

3Volume of stationary object

If the exhaust muffler dimensions are increased, then the interior volume increases, but the exhaust muffler bumps into the crankshaft and piston rod

Engineering Contradiction:
Improveinterior volumeVSAvoidcollision with internal components
Core Design Contradiction:
Volume of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The interior volume is increased by elongating the muffler in the length direction (along the refrigerant flow direction) rather than expanding in width or height. This dimensional strategy ensures adequate internal volume for noise attenuation while maintaining sufficient clearance in the transverse direction to avoid collision with the crankshaft and piston rod during their reciprocating motion.

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

Solution Approach 2:

The asymmetric oval cross-section with length significantly greater than width creates an elongated volume distribution that directs the increased interior space along the flow path away from the region where the crankshaft and piston rod operate, thereby preventing collision while maximizing noise attenuation volume.

Inventive Principle:
Principle #4Asymmetry

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 reduces pressure losses and improves compressor efficiency while effectively attenuating noise at specific frequencies, preventing the muffler from colliding with internal components.

Implementation Method 1

Under high pressure, pressure fluctuations occur in the refrigerant fluid upon exit from the cylinder originating from the reciprocating motion of the piston. Noise is generated resulting from these pressure fluctuations and flow of the refrigerant during passage of the fluid into the exhaust muffler. The exhaust muffler provides attenuation in certain frequencies of the generated noise

Methodology Applied
Scientific EffectPressure fluctuations:

Data Source

PatentEP2580475B1A hermetic compressor
Publication Date: 2014.04.30 ARCELIK AS
  • EP2580475B1 patent drawingFigure 1
  • EP2580475B1 patent drawingFigure 2
  • EP2580475B1 patent drawingFigure 3

AI summary

The present invention relates to a hermetic compressor (1) that comprises a casing (2), a motor (5) disposed inside the casing (2), a cylinder (6) providing the refrigerant fluid to be pumped, a piston (7) functioning in the cylinder (6), providing the refrigerant fluid to be compressed into the cylinder (6) hole, a crankshaft (8) that transfers the motion delivered from the motor (5) and a piston rod (9) that transfers the motion received from the crankshaft (8) to the piston (7), a block (10) carries and/or bears the basic mechanical components like the cylinder (6), the piston (7), the crankshaft (8) and the piston rod (9), a suction muffler (3), disposed in the casing (2), providing the noise generated during suction of the refrigerant fluid to be attenuated and at least one exhaust muffler (4), disposed on the block (10), having a hollow, closed volume, providing the noise generated during pumping of the refrigerant fluid to be attenuated.