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 they deteriorate over time and require periodic calibration, which is time-consuming and cannot be done while the container is sealed.
Innovation Solution
A container refrigeration apparatus with a gas supply device that switches between nitrogen-enriched and outside air supply states, allowing for calibration of oxygen sensors using outside air without needing to replace the air inside the container, using a branch pipe and open/close valve to divert air for calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the container is opened to replace air for sensor calibration, then the oxygen sensor can be calibrated using outside air, but the calibration process takes a long time and cannot be done during transportation
Solution Approach 1:
The air supply system is segmented into two separate paths: one for container air circulation and another for sensor calibration. The calibration path draws outside air directly to the sensor without requiring full container air replacement, enabling independent calibration operation.
Solution Approach 2:
A calibration air intake mechanism serves as an intermediary, providing a direct pathway for outside air to reach the oxygen sensor during transportation. This intermediary system eliminates the need to open the container for calibration purposes.
2Measurement precision
If the container air is completely replaced with outside air for calibration, then the oxygen sensor can be calibrated accurately, but the preparation time is extended
Solution Approach 1:
Instead of completely replacing the container air for calibration, the system performs partial action by introducing a controlled amount of outside air specifically to the sensor through the calibration pathway. This partial action achieves calibration without the excessive time required for full air replacement.
3Reliability
If nitrogen-enriched air is supplied to control oxygen concentration, then plant freshness is maintained, but the oxygen sensor may drift from actual values over time
Solution Approach 1:
The system incorporates periodic calibration operations that provide feedback to the oxygen sensor, correcting any drift from actual oxygen concentration values. This feedback mechanism ensures continued measurement accuracy while maintaining the nitrogen-enriched atmosphere for plant preservation.
Solution Approach 2:
The calibration system enables the oxygen sensor to self-correct its measurements by periodically comparing readings against known outside air oxygen concentration, eliminating the need for manual intervention or container opening for calibration purposes.
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 without waiting for air replacement, ensuring accurate oxygen concentration control and maintaining freshness of stored plants.
Implementation Method 1
a refrigerant circuit (20) to which an evaporator (24) that allows air in the container (11) to exchange heat with a refrigerant is connected, and in which the refrigerant circulates to perform a refrigeration cycle
Implementation Method 2
an evaporator (24) that allows air in the container (11) to exchange heat with a refrigerant
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 supplied into the container (11)... producing, from outside air, nitrogen-enriched air having a higher nitrogen concentration and lower oxygen concentration than the outside air
Implementation Method 4
an oxygen sensor (51) which measures an oxygen concentration of the air in the container (11)
Implementation Method 5
an open/close valve (82) which opens/closes the branch pipe (81)
Data Source
AI summary
A gas supply device 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 containe, and a second supply state in which the gas supply device takes outside air therein and supplies, as supply air, the outside air into the container. A CA system is provided with a branch pipe which guides at least part of the supply air flowing through a supply passage to an oxygen sensor, and an open/close valve which opens/closes the branch pipe. An outside air calibration operation is performed in which the open/close valve is opened in the second supply state to guide the least part of the outside air flowing through the supply passage to the oxygen sensor, thereby calibrating the oxygen sensor using the outside air.