Container Refrigeration Gas Mixture Supply for Stable Oxygen Control

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Solution Overview

Problem

Existing container refrigeration systems face challenges in maintaining a stable oxygen concentration, leading to respiratory disorders and deterioration of plants due to excessive variations in oxygen levels, which are difficult to control with nitrogen gas supply methods.

Innovation Solution

A container refrigeration apparatus equipped with an oxygen concentration detector and a gas mixture supplier that adjusts the oxygen concentration by providing a gas mixture with a higher nitrogen and lower oxygen concentration than outside air, allowing for precise control by stopping or increasing the gas supply based on detected levels to maintain a target concentration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If nitrogen gas is supplied into the container to reduce oxygen concentration, then the oxygen concentration can be quickly reduced to target level, but the magnitude of variation in oxygen concentration increases causing excessive decrease and making it difficult to maintain stable target concentration

Engineering Contradiction:
Improvespeed of oxygen concentration reductionVSAvoidstability of oxygen concentration
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent introduces a gas mixture containing both nitrogen and oxygen as an intermediary substance, rather than using pure nitrogen. This gas mixture acts as a mediator that gradually reduces oxygen concentration while preventing excessive decreases, thereby resolving the contradiction between fast reduction speed and concentration stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the composition parameters of the supplied gas from pure nitrogen to a nitrogen-oxygen mixture with specific ratios. By adjusting the oxygen content in the supplied gas, the system achieves both rapid oxygen concentration reduction and stable maintenance of target levels, resolving the contradiction between speed and stability.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If oxygen concentration is reduced too low to quickly maintain freshness, then respiration rate decreases, but plants develop respiratory disorders and deteriorate

Engineering Contradiction:
Improvefreshness maintenance efficiencyVSAvoidrespiratory disorders of plants
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent employs oxygen concentration detection and feedback control mechanisms that monitor the container's oxygen levels and adjust gas supply accordingly. This feedback system prevents oxygen concentration from dropping below safe thresholds, avoiding plant respiratory disorders while maintaining freshness through efficient concentration control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent supplies a gas mixture containing oxygen alongside nitrogen, providing a cushioning effect that prevents oxygen concentration from dropping too low. This beforehand cushioning ensures that while oxygen is reduced to slow respiration, it never falls to levels that would cause plant respiratory disorders.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 solution reduces the magnitude of oxygen concentration variation, effectively maintaining the oxygen level near the target concentration, thereby preventing respiratory disorders and extending the freshness of plants.

Implementation Method 1

an oxygen concentration detector (51) which detects an oxygen concentration in the interior of the container (11)

Methodology Applied
Scientific EffectOxygen detection:

Implementation Method 2

the oxygen concentration in the interior of the container (11) is reduced to the target concentration by respiration of the plants (15) absorbing oxygen in the air and releasing carbon dioxide into the air

Methodology Applied
Scientific EffectRespiration:

Data Source

PatentEP3054244B1Refrigeration unit for container
Publication Date: 2019.01.30 DAIKIN INDUSTRIES LTD
  • EP3054244B1 patent drawingFigure 1
  • EP3054244B1 patent drawingFigure 2
  • EP3054244B1 patent drawingFigure 3

AI summary

An oxygen concentration in the interior of a container (11) is detected by an oxygen concentration detection sensor (51). If the oxygen concentration detected by the oxygen concentration detection sensor (51) is higher than that of a gas mixture, the container (11) is supplied with the gas mixture having an oxygen concentration lower than that of the outside air and higher than a target concentration. The oxygen concentration in the interior of the container (11) is reduced to the vicinity of the oxygen concentration of the gas mixture by supplying the interior of the container (11) with the gas mixture, and then is further reduced to the target concentration by respiration of plants (15). This appropriately controls the oxygen concentration in the interior of the container (11), and reduces a decrease in the degree of freshness of the plants.