Injection Muffler with Nested Fixation to Reduce Refrigerant Pulsation

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Solution Overview

Problem

The existing muffler designs for refrigerant injection pipes in refrigeration and air-conditioning systems have weak installation strength due to mismatched diameters, leading to inadequate prevention of pulsations and potential damage or breakage of the injection pipe.

Innovation Solution

A compressor unit with an injection muffler having an inner diameter larger than both the compressor and expansion valve connecting parts, securely fixed to the compressor, to effectively mitigate pulsations caused by refrigerant flow-back.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a muffler with large inner diameter and length is used to prevent pulsations, then pulsation prevention capability is improved, but installation strength becomes weak due to difficulty in stable fixation

Engineering Contradiction:
Improvepulsation prevention capabilityVSAvoidinstallation strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The injection muffler is nested within the compressor structure, with the muffler body positioned inside the compressor housing and fixed to the compressor shell. This nesting arrangement allows the muffler to benefit from the compressor's structural strength while maintaining its pulsation damping function, resolving the contradiction between large muffler size and stable installation.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent introduces an intermediary mounting structure that connects the muffler to the compressor. This intermediary mechanism provides stable fixation points and structural support, enabling the large-diameter muffler to be securely installed without compromising its pulsation prevention capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the injection pipe inner diameter is increased to reduce pulsations, then pulsation amplitude is reduced, but the pipe becomes more prone to damage or breakage due to weak fixation

Engineering Contradiction:
Improvepulsation amplitudeVSAvoidpipe damage prevention
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The injection pipe is nested within the compressor structure, with the pipe fixed to the compressor shell at multiple points. This nesting arrangement provides structural support and stable fixation, allowing the pipe to maintain a larger inner diameter for reduced pulsations while preventing damage through the compressor's structural reinforcement.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

The larger inner diameter of the injection muffler significantly reduces pulsations and prevents damage or breakage of the injection pipe by enhancing the installation strength and stability of the muffler.

Implementation Method 1

an injection muffler disposed between the compressor connecting part and the expansion valve connecting part

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP3460244B1Compressor unit
Publication Date: 2020.03.11 MITSUBISHI ELECTRIC CORP
  • EP3460244B1 patent drawingFigure 1
  • EP3460244B1 patent drawingFigure 2
  • EP3460244B1 patent drawingFigure 3

AI summary

An injection pipe, which constitutes a part of a refrigerant pipe connecting a compressor and a condenser, permits a part of refrigerant flowing out of the condenser to branch off and flow into the compressor. The injection pipe includes: a compressor connecting part connected to the compressor; an expansion valve connecting part connected to an electronic expansion valve disposed between the injection pipe and the condenser; and an injection muffler disposed between the compressor connecting part and the expansion valve connecting part. The injection muffler has an inner diameter larger than an inner diameter of the compressor connecting part and an inner diameter of the expansion valve connecting part. The injection muffler is fixed to a side of the compressor.