Refrigerant Distributor with Tapered Paths to Prevent Sludge Clogging

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Solution Overview

Problem

In refrigeration cycle apparatuses, the use of capillary tubes in distributors leads to vortex generation and dead water regions, causing sludge deposition and clogging, especially with chemically unstable refrigerants like HFO1123, which degrades the apparatus's performance and reliability.

Innovation Solution

The introduction of tapered paths between refrigerant outflow and distribution paths in the distributor prevents drastic narrowing of the flow paths, reducing vortex generation and dead water regions, thereby preventing sludge deposition and ensuring even refrigerant distribution to the evaporator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If capillary tubes are used to connect the distributor to the heat exchanger paths, then the refrigerant flow paths are drastically narrowed, but this generates vortex and creates dead water regions causing sludge deposition and clogging

Engineering Contradiction:
Improverefrigerant flow rate controlVSAvoidcapillary tube clogging resistance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The flow path is divided into multiple segments: the distribution path, tapered paths with gradual narrowing, and capillary tubes. This segmentation allows the refrigerant to gradually adapt to the narrowing geometry, preventing sudden flow direction changes that cause vortex formation and dead water regions, thereby reducing sludge deposition while maintaining flow rate control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tapered paths are designed with curved, gradual narrowing geometry rather than sharp angles. This curved transition smooths the refrigerant flow, preventing flow separation and vortex formation at the entrance of capillary tubes, thus eliminating dead water regions where sludge would deposit.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If the refrigerant flow paths are drastically narrowed at the capillary tube entrance, then the refrigerant distribution is concentrated, but this creates dead water regions where sludge is deposited

Engineering Contradiction:
Improverefrigerant distribution efficiencyVSAvoidsludge deposition
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The tapered paths perform a preliminary action by gradually narrowing the flow path before the refrigerant enters the capillary tubes. This pre-conditioning of the flow reduces turbulence and prevents dead water region formation, thereby preventing sludge deposition before it can occur in the capillary tubes.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If conventional distributor with capillary tubes is used, then the structure is simple, but the vortex generation leads to dead water regions and sludge clogging over time

Engineering Contradiction:
Improvedistributor structureVSAvoiddistributor service life
Core Design Contradiction:
Device complexityVSDuration of action of stationary object

Solution Approach 1:

The tapered paths introduce a dynamic gradient in the flow path geometry, transitioning from wider to narrower sections. This dynamic geometry optimizes flow characteristics throughout operation, preventing vortex formation and dead water regions, thereby extending the distributor's service life by preventing sludge clogging.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3246639B1Distributor and refrigeration cycle apparatus
Publication Date: 2019.12.25 MITSUBISHI ELECTRIC CORP
  • EP3246639B1 patent drawingFigure 1~2
  • EP3246639B1 patent drawingFigure 3A~3B
  • EP3246639B1 patent drawingFigure 3C

AI summary

A distributor 5 includes a main body 54. The main body 54 includes a refrigerant inflow path 101, a plurality of refrigerant outflow paths 104a and 104b, a distribution path 102 communicating with the refrigerant inflow path 101 and the plurality of refrigerant outflow paths 104a and 104b, and a plurality of tapered paths 103a, 103b, and 103c each communicating between corresponding one of the plurality of refrigerant outflow paths 104a and 104b and the distribution path 102. The tapered paths each have an inlet opening and an outlet opening, the inlet opening being larger than the outlet opening.