Hermetic Compressor Overheat Prevention via Insulated Valve

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Solution Overview

Problem

Existing hermetic compressors face overheating issues due to temperature differences between high and low pressure portions, leading to inefficient operation and potential damage, as the overheat preventing units are affected by the cold low pressure portion temperatures and require costly replacements.

Innovation Solution

An overheat preventing unit is configured with a separate insulating material between the valve and the high/low pressure dividing plate, featuring gas holes for both side surfaces to communicate with the high pressure portion, allowing the valve to accurately respond to temperature changes without direct contact, thus preventing overheating and reducing assembly costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the overheat preventing unit is directly coupled to the high/low pressure dividing plate, then the structure is simple and assembly is easy, but the valve is affected by the cold low pressure portion temperatures leading to inaccurate temperature detection

Engineering Contradiction:
Improvetemperature detection accuracyVSAvoidoverheat preventing unit structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A heat insulating member is introduced as an intermediary between the overheat preventing unit and the high/low pressure dividing plate. This insulating member prevents heat transfer from the low pressure portion to the overheat preventing unit, allowing the valve to accurately detect the temperature of the high pressure portion without being influenced by the colder low pressure portion temperatures.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the valve is directly contact with the high/low pressure dividing plate, then the assembly cost is low, but the valve requires costly replacements when damaged

Engineering Contradiction:
Improveassembly costVSAvoidvalve replacement cost
Core Design Contradiction:
Ease of manufactureVSEase of repair

Solution Approach 1:

The overheat preventing unit is designed as a separate, detachable component that can be independently replaced. The unit includes a valve, a spring, and a heat insulating member that are assembled together as a module. When the valve becomes damaged, only this modular overheat preventing unit needs to be replaced rather than the entire high/low pressure dividing plate, significantly reducing repair costs.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If the valve responds to both high and low pressure portion temperatures, then the temperature reflection is comprehensive, but the overheat detection accuracy is reduced

Engineering Contradiction:
Improveoverheat detection accuracyVSAvoidtemperature response range
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The heat insulating member acts as a selective mediator that blocks thermal energy from the low pressure portion while allowing the valve to sense thermal conditions from the high pressure portion. This selective heat transfer control enables the valve to respond specifically to high pressure portion temperatures for accurate overheat detection, without being influenced by the broader temperature range including the cooler low pressure portion.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution effectively prevents compressor damage by accurately reflecting high pressure portion temperatures and minimizing the impact of low pressure portion temperatures, enhancing the reliability and reducing the cost of component replacements.

Implementation Method 1

a valve plate (185) made of a bimetal which is thermally deformed according to a temperature difference between the high pressure portion (112) and the low pressure portion (111)

Methodology Applied
Scientific EffectBimetallic strip effect: Bi-Metallic Strip

Implementation Method 2

a heat insulating member (184) made of an insulating material may be interposed between the overheat preventing unit (180) and the high/low pressure dividing plate (115)

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3211238B1Hermetic compressor
Publication Date: 2023.09.06 LG ELECTRONICS INC
  • EP3211238B1 patent drawingFigure 1
  • EP3211238B1 patent drawingFigure 2A~2B
  • EP3211238B1 patent drawingFigure 3

AI summary

A hermetic compressor according to the present application includes a casing having an inner space, an orbiting scroll provided in the inner space, a non-orbiting scroll engaged with the orbiting scroll to form compression chambers, a high/low pressure dividing plate dividing the inner space into high and low pressure portions, and an overheat preventing unit coupled to a surface of the dividing plate at the high pressure portion, having a communication hole formed through the dividing plate to communicate the high and low pressure portions, and having a valve spaced from the dividing plate by a predetermined interval to selectively open/close the communication hole according to temperature variation of the high pressure portion, whereby transfer of refrigerant temperature of the low pressure portion to the overheat preventing unit through the dividing plate can be prevented, and the compressor can be quickly stopped upon being overheated, thereby being protected from damage.