1、 Program objectives

By deploying a precise, stable, and networked gas detection system, 24-hour continuous monitoring of key gases (ethylene, carbon dioxide, oxygen) in the fresh-keeping warehouse can be achieved, providing data basis for gas control equipment (such as deoxygenation machines, de ethylene machines, carbon dioxide removal machines, nitrogen generators), achieving manual or automatic regulation, and creating the best fresh-keeping gas environment.

2、 Core Monitoring Gas and Its Significance

1. Ethylene (C ₂ H ₄):

·Role: "Maturation hormone" is a key factor in the ripening and aging of fruits and vegetables.

·Monitoring purpose: Timely monitor its concentration. Once it exceeds the standard, start the ethylene removal device to remove it, effectively suppressing excessive ripening, softening, and rotting of fruits and vegetables. It is crucial for fruits that are sensitive to ethylene, such as kiwi, banana, mango, etc.

2. Carbon dioxide (CO ₂):

·Role: Respiratory products, high concentration can inhibit respiration, but excessive concentration can lead to fruit and vegetable poisoning (browning, odor).

·Monitoring purpose: Accurately control its concentration (usually maintained at 1% -10%, depending on the variety), and find the optimal balance between inhibiting respiration and preventing toxicity.

3. Oxygen (O ₂):

·Role: Breathing is necessary. Low oxygen environment can effectively inhibit respiration and microbial growth.

·Monitoring purpose: To maintain a stable low oxygen environment (usually 2% -5%), slow down metabolism, and extend shelf life. At the same time, prevent low oxygen concentration from causing fruits and vegetables to breathe anaerobically and produce alcohol flavor.

4. Optional monitoring items: temperature and humidity

·Temperature and humidity are the foundation of controlled atmosphere preservation, usually integrated or linked with gas detectors. The synergistic effect of stable and suitable low-temperature and high humidity environment and gas regulation.

3、 Technical solution configuration suggestions

Plan A: Distributed multi-point online monitoring system (recommended for large and medium-sized air conditioning warehouses and logistics storage centers)

·System composition:

1. Online gas sensors: Multiple fixed monitoring points are deployed at different locations in the warehouse (such as the top, middle, bottom, inlet, and outlet).

2. Gas sampling system: optional centralized monitoring system with multi-point rotating sampling to reduce costs.

3. Central control unit/PLC: Collect all sensor data and display it on the touch screen.

4. Linkage control module: automatically controls the start and stop of fans and controlled atmosphere equipment (nitrogen generator, carbon dioxide removal machine, ethylene removal machine) according to the set threshold.

5. Remote monitoring platform (Internet of Things): Data is uploaded to the cloud platform or local server through 4G/Wi Fi, supporting remote real-time viewing, receiving over limit alarms, generating historical data curves and reports on computers and mobile apps.

·Advantages: Real time continuous operation, unmanned operation, automatic control, complete data, and efficient management.

·Example of core equipment:

·Online three in one gas transmitter: simultaneously monitoring O ₂, CO ₂, C ₂ H ₄.

·Wall mounted or pipe mounted installation.

Plan B: Portable Inspection Plan (suitable for regular inspections of small cold storage and warehouses, as well as spot checks during transportation)

·System composition:

1. Handheld multi in one gas detector: integrates O ₂, CO ₂, C ₂ H ₄ sensors, and may also include temperature and humidity.

2. Pump suction sampling: It can actively suck the gas in the warehouse into the instrument for detection.

3. Data recording function: Automatically record data during inspection, which can be exported and analyzed through USB in the future.

·Advantages: Flexible and adaptable, low cost, suitable for multi-point sampling inspection.

·Example of core equipment:

·Portable pump suction ethylene/carbon dioxide/oxygen detector.

4、 Technical specifications requirements for key equipment

1. Sensor type:

·Ethylene (C ₂ H ₄): Electrochemical (low-cost) or photoionization (PID, high-precision, fast).

·Carbon dioxide (CO ₂): Infrared (NDIR) principle, stable and long-lasting.

·Oxygen (O ₂): Electrochemical formula.

2. Range and accuracy (example):

·Ethylene: 0-100 ppm, resolution 0.1 ppm, accuracy ± 3% FS.

·Carbon dioxide: 0-5000 ppm or 0-20%, accuracy ± 50 ppm+3% reading.

·Oxygen: 0-25%, accuracy ± 0.5%.

3. Protection and Durability: The equipment needs to adapt to low temperature and high humidity environments (such as 0-5 ° C, humidity>90%), the shell should be treated with anti condensation, and the sensor should be anti condensation.

4. Calibration: The equipment needs to support on-site calibration and provide regular calibration services to ensure long-term accuracy of data.

5、 Value and benefits of the plan

1. Reduce losses: Accurately control the gas environment to significantly reduce the loss rate of fruits and vegetables (from traditional storage of 10% -30% to below 5%).

2. Improve quality: Maintain the color, hardness, taste, and nutritional value of fruits and vegetables, achieve off-season sales, and increase premium value.

3. Optimize energy consumption: Control equipment operation based on precise data to avoid ineffective operation and save energy.

4. Digital management: Achieve traceability, quantification, and optimization of the preservation process, providing data support for refined management.

5. Ensure safety: prevent the risk of suffocation when personnel enter the warehouse due to low oxygen levels (oxygen deficiency alarm should be equipped).