Discharge muffler and two-stage compressor with discharge muffler

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Solution Overview

Problem

In two-stage compressors, under conditions where the suction pressure and discharge pressure difference is small, the pressure difference between the discharge muffler and the compressor casing decreases, leading to reduced discharge of refrigerating machine oil accumulated in the muffler, causing oil accumulation issues.

Innovation Solution

The discharge muffler design includes an outlet path with its inlet opening in the lower space, allowing both refrigerant gas and oil to be discharged, and strategically arranging the inlet and outlet paths to prevent quick oil flow and immersion, enabling efficient oil discharge without an oil return pipe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the pressure difference between discharge muffler and compressor casing is small, then the compressor can operate under small pressure differential conditions, but the refrigerating machine oil discharge efficiency deteriorates

Engineering Contradiction:
Improveoperating condition rangeVSAvoidoil discharge efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The outlet path inlet is positioned in the lower space of the muffler container, creating a dynamic discharge mechanism where oil is discharged through the outlet path when the liquid level rises, rather than relying solely on pressure differential. This dynamic level-based discharge ensures effective oil removal across various operating conditions including small pressure differentials.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The lower space acts as an intermediary chamber that collects separated oil from the refrigerant gas. By positioning the outlet path inlet in this lower space, the system creates an intermediate collection zone that facilitates oil discharge independent of the main pressure differential between muffler and compressor casing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the outlet path inlet is positioned in the lower space, then oil discharge efficiency is improved, but the risk of refrigerant gas short-circuiting increases

Engineering Contradiction:
Improveoil discharge efficiencyVSAvoidrefrigerant gas flow control
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The muffler container is segmented into an upper space for refrigerant gas flow and noise cancellation, and a lower space for oil separation and discharge. This spatial segmentation allows the outlet path inlet to access the lower space for effective oil discharge while the upper space maintains proper refrigerant gas flow paths, preventing short-circuiting.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the muffler container are assigned different functions: the upper space is optimized for refrigerant gas flow and noise cancellation, while the lower space is optimized for oil separation and discharge. This local functional differentiation allows the outlet path to efficiently discharge oil without disrupting the refrigerant gas flow in the upper space.

Inventive Principle:
Principle #3Local quality

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 design effectively reduces oil accumulation in the muffler by ensuring continuous discharge of refrigerating machine oil and maintaining noise cancellation functionality, even under varying flow velocities, and allows oil to be returned to the compressor casing.

Implementation Method 1

the refrigerating machine oil contained in the refrigerant gas is separated from the refrigerant gas by centrifugal force caused due to the turning of the refrigerant gas

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2416011B1Discharge muffler and two-stage compressor with discharge muffler
Publication Date: 2019.05.01 DAIKIN INDUSTRIES LTD
  • EP2416011B1 patent drawingFigure 1
  • EP2416011B1 patent drawingFigure 2
  • EP2416011B1 patent drawingFigure 3

AI summary

A discharge muffler (1) includes a muffler container (2). In the muffler container (2), refrigerating machine oil is separated from refrigerant gas containing the refrigerating machine oil, and the refrigerating machine oil is stored in a lower space (2b). An inlet (7c) of an outlet pipe (7) connected to the muffler container (2) opens in the lower space (2b).