Screw compressor and freezer

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Solution Overview

Problem

Screw compressors face issues with gate rotor damage due to pressure acting in a direction opposite to the normal direction during operation, leading to potential structural failure.

Innovation Solution

A gate rotor assembly design featuring a first and second support member made of metal, supporting the gate rotor from both the back and front surfaces, with a gap between the support members allowing slight radial and circumferential movement, and divided gate blocks to accommodate thermal expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If a screw compressor is used in a freezer, then the compressor can operate continuously, but ice accumulates on the suction port of the compressor leading to operational issues

Engineering Contradiction:
Improvecompressor operation continuityVSAvoidice accumulation on suction port
Core Design Contradiction:
Duration of action of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and removes ice from the suction port area using a dedicated ice removal mechanism. A blade or scraper is positioned to contact the suction port and actively remove accumulated ice, preventing the harmful effects of ice blockage while allowing continuous compressor operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary component (ice removal blade/scraper) between the suction port and the accumulating ice. This intermediary element facilitates ice removal by mechanically contacting and eliminating the ice buildup, resolving the contradiction between continuous operation and ice accumulation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the evaporator is positioned above the freezer chamber, then cooling efficiency is improved, but water from defrosting accumulates and freezes on the compressor

Engineering Contradiction:
Improvecooling efficiencyVSAvoidwater accumulation and freezing on compressor
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and removes water from the compressor surface using a drainage system. Channels or grooves are provided on the compressor housing to collect and drain water away from the compressor, preventing water accumulation and subsequent freezing that would harm compressor operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses hydraulic principles through drainage channels and gravity-driven water flow to remove water from the compressor area. The channels guide water away from the compressor surface, utilizing gravity and fluid flow to prevent water accumulation and freezing.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Productivity

If the freezer chamber is positioned above the refrigerator chamber, then cold air circulation is improved, but condensation forms on the refrigerator chamber door

Engineering Contradiction:
Improvecold air circulationVSAvoidcondensation on refrigerator door
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention applies local quality by providing thermal insulation specifically at the refrigerator chamber door area. Insulation layers or thermal barriers are positioned at the door to prevent cold air from the upper freezer chamber from causing condensation on the door surface, while maintaining overall cold air circulation.

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

Enhances strength against unusual pressure directions and reduces wear by allowing the gate rotor to follow screw rotor changes, maintaining meshing integrity and preventing damage.

Implementation Method 1

a suction port heating section that heats the refrigerant gas sucked by the compression section

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a defrosting section that supplies heated air to a surface of the evaporator

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

a compression section that compresses the refrigerant gas

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP4477887B1Screw compressor and freezer
Publication Date: 2026.04.08 DAIKIN INDUSTRIES LTD
  • EP4477887B1 patent drawingFigure 1
  • EP4477887B1 patent drawingFigure 2
  • EP4477887B1 patent drawingFigure 3

AI summary

A gate rotor assembly (50) includes a gate rotor (51) including a plurality of flat plate-shaped gates (53) that mesh with helical grooves (41) of the screw rotor (40); a first support member (56) made of a metal and including a plurality of first gate support portions (84) that each support a corresponding one of the gates (53) from the back surface side of the corresponding gate (53); and a second support member (58) made of a metal and including a plurality of second gate support portions (92) that each support a corresponding one of the gates (53) from the front surface side of the corresponding gate (53).