Refrigeration device for container
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Solution Overview
Problem
Container refrigeration apparatuses lack a means to measure nitrogen concentration, making it difficult to detect malfunctions in the gas supply device without increasing manufacturing costs, and it is challenging to determine if oxygen concentration control errors are due to device malfunction or poor airtightness.
Innovation Solution
Incorporating an oxygen concentration sensor that measures the oxygen concentration of nitrogen-enriched air produced by the gas supply device, with a measurement passage and on-off valve to direct a portion of the nitrogen-enriched air for measurement, allowing the controller to control the gas supply device operation and detect malfunctions without additional nitrogen concentration sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nitrogen concentration sensor is provided for the gas supply device to detect malfunctions, then detection capability is improved, but manufacturing cost increases
Solution Approach 1:
The oxygen concentration sensor is made to serve dual purposes: measuring oxygen concentration in the container atmosphere for plant preservation, and measuring oxygen concentration in the nitrogen-enriched air from the gas supply device for malfunction detection. This multi-functionality eliminates the need for a separate nitrogen concentration sensor, resolving the contradiction between detection capability and manufacturing cost.
Solution Approach 2:
The patent uses oxygen concentration as an intermediary parameter to indirectly monitor nitrogen concentration. Since nitrogen-enriched air has lower oxygen concentration, measuring oxygen concentration serves as a proxy for detecting nitrogen concentration and gas supply device performance, avoiding the need for expensive nitrogen-specific sensors.
2Reliability
If the oxygen concentration of air in the container is reduced to control plant respiration, then freshness is improved, but measurement capability deteriorates without nitrogen concentration sensor
Solution Approach 1:
The system performs preliminary measurement of oxygen concentration in the nitrogen-enriched air before it enters the container. This allows the controller to verify gas supply device performance in advance, detecting malfunctions before they affect the container atmosphere, thus maintaining both freshness and measurement capability.
Solution Approach 2:
The patent implements a feedback mechanism where the oxygen concentration sensor continuously monitors the nitrogen-enriched air, and the controller adjusts gas supply based on this feedback. This closed-loop control ensures proper oxygen concentration in the container while using the same sensor data to detect gas supply device malfunctions.
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 detection of gas supply device malfunctions and determination of oxygen concentration control errors without increasing manufacturing costs, ensuring accurate control of oxygen levels in the container.
Implementation Method 1
an oxygen concentration sensor (51) which measures an oxygen concentration of the air in the container (11)
Implementation Method 2
a measurement passage (88) which guides part of the nitrogen-enriched air passing through the supply passage (44) to the oxygen concentration sensor (51)
Implementation Method 3
a refrigerant circuit (20) where a refrigerant circulates to perform a refrigeration cycle
Implementation Method 4
The container refrigeration apparatus allows heat exchange in an evaporator (24) connected to the refrigerant circuit (20) between air in the container (11) and the refrigerant to cool the air
Implementation Method 5
an on-off valve (82) provided for the measurement passage (88)
Data Source
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AI summary
Disclosed herein is a container refrigeration apparatus (10) for cooling air in a container (11). The container refrigeration apparatus (10) includes: a gas supply device (30) which produces nitrogen-enriched air having a higher nitrogen concentration than outside air and supplies the nitrogen-enriched air into the container (11) via a supply passage (44); an oxygen concentration sensor (51) which measures an oxygen concentration of the air in the container (11); and a controller which controls the operation of the gas supply device (30) so that the oxygen concentration measured by the oxygen concentration sensor (51) reaches a target concentration. The container refrigeration apparatus (10) is provided with a measurement passage (88) which guides part of the nitrogen-enriched air passing through the supply passage (44) to the oxygen concentration sensor (51), and an on-off valve (82) is provided for the measurement passage (88).