Refrigeration device for container

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Solution Overview

Problem

Existing container refrigeration systems face challenges in calibrating oxygen sensors within the container during transportation, as sensors deteriorate over time and require periodic calibration, which is time-consuming and cannot be performed during transit due to the need to open the container.

Innovation Solution

A container refrigeration apparatus with a gas supply device that switches between nitrogen-enriched air and outside air supply states, allowing for on-demand calibration of oxygen sensors using outside air without replacing the container's air, via a branch pipe and open/close valve configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the container is opened to replace air for oxygen sensor calibration, then the oxygen sensor can be calibrated using outside air, but the calibration process takes a long time and cannot be performed during transportation

Engineering Contradiction:
Improveoxygen sensor calibration accuracyVSAvoidcalibration preparation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the air supply system into two independent pathways: a main supply passage for providing air to the container interior, and a separate calibration supply passage connected to the oxygen sensor. This segmentation allows calibration air to be supplied independently without requiring container opening or complete air replacement, thus reducing calibration time while maintaining accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a calibration air supply passage as an intermediary pathway that directly connects the outside air source to the oxygen sensor. This intermediary channel enables calibration to occur without involving the main container air space, allowing rapid calibration during transportation without the time-consuming process of replacing the entire container atmosphere.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the container air is completely replaced with outside air for calibration, then the oxygen sensor can be calibrated accurately, but the process requires opening the container and takes considerable time

Engineering Contradiction:
Improveoxygen sensor calibration accuracyVSAvoidcalibration efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the air supply function into calibration-specific and container ventilation functions by providing separate supply passages. The calibration supply passage delivers outside air directly to the sensor location, enabling accurate calibration without requiring complete container air replacement, thus improving calibration efficiency while maintaining accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The calibration air supply passage is pre-configured and connected within the container system, allowing calibration to be performed immediately by switching the air supply mode. This preliminary preparation eliminates the need for time-consuming container opening and air replacement procedures, enabling rapid calibration without compromising accuracy.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If nitrogen-enriched air is supplied to control oxygen concentration in the container, then plant freshness is maintained, but the oxygen sensor may become inaccurate over time requiring calibration

Engineering Contradiction:
Improveplant freshness maintenanceVSAvoidoxygen concentration measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces a dedicated calibration air supply passage that provides an intermediary pathway for introducing known concentration outside air to the oxygen sensor. This separate calibration channel allows periodic verification and adjustment of sensor accuracy without disrupting the nitrogen-enriched atmosphere in the container, maintaining both plant freshness conditions and measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent enables dynamic switching between normal operation mode (nitrogen-enriched air supply for plant preservation) and calibration mode (outside air supply through the calibration passage for sensor accuracy). This parameter change in air composition and supply pathway allows the system to maintain both reliable plant freshness control and accurate oxygen concentration measurement through periodic calibration.

Inventive Principle:
Principle #35Parameter changes

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

Enables prompt calibration of oxygen sensors at any time, reducing the need for air replacement and allowing continuous monitoring of oxygen and carbon dioxide concentrations to maintain optimal conditions for stored plants.

Implementation Method 1

a refrigerant circuit (20) to which an evaporator (24) that is configured to allow air in the container (11) to exchange heat with a refrigerant is connected, and in which the refrigerant is circulatable to perform a refrigeration cycle

Methodology Applied
Scientific EffectRefrigeration cycle:

Implementation Method 2

an evaporator (24) that is configured to allow air in the container (11) to exchange heat with a refrigerant

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

a gas supply device (30) having a supply passage (44) which communicates with an inside of the container (11) and through which supply air is suppliable into the container (11)... producing, from outside air, nitrogen-enriched air having a higher nitrogen concentration and lower oxygen concentration than the outside air

Methodology Applied
Scientific EffectGas separation:

Implementation Method 4

an oxygen sensor (51) which is configured to measure an oxygen concentration of the air in the container (11)

Methodology Applied
Scientific EffectOxygen concentration measurement:

Implementation Method 5

A branch pipe (81) which is connected, at one end, to the supply passage (44) and, at the other end, coupled to the oxygen sensor (51), and configured to guide at least part of the supply air flowing through the supply passage (44) to the oxygen sensor (51)

Methodology Applied
Scientific EffectGas flow guidance:

Data Source

PatentEP3258192B1Refrigeration device for container
Publication Date: 2021.11.10 DAIKIN INDUSTRIES LTD
  • EP3258192B1 patent drawingFigure 1
  • EP3258192B1 patent drawingFigure 2
  • EP3258192B1 patent drawingFigure 3

AI summary

A gas supply device (30) is configured such that its supply state is switchable between a first supply state supplying, as supply air, nitrogen-enriched air produced from outside air into a container (11), and a second supply state in which the gas supply device (30) takes outside air therein and supplies, as supply air, the outside air into the container (11). A CA system (60) is provided with a branch pipe (81) which guides at least part of the supply air flowing through a supply passage (44) to an oxygen sensor (51), and an open/close valve (82) which opens/closes the branch pipe (81). An outside air calibration operation is performed in which the open/close valve (82) is opened in the second supply state to guide the least part of the outside air flowing through the supply passage (44) to the oxygen sensor (51), thereby calibrating the oxygen sensor (51) using the outside air.