【Case Study】Application of CVF-3000W-6P Vacuum Precooler in a Yunnan Leafy Vegetable Export Enterprise
A large leafy vegetable export enterprise in Kunming, Yunnan, processes approximately 15 tons of leafy greens such as spinach, lettuce, and choy sum daily.
[Case Study] Application of CVF-3000W-6P Vacuum Precooler at a Yunnan Leafy Vegetable Export Enterprise
I. Customer Background
A large leafy vegetable export enterprise in Kunming, Yunnan, processes approximately 15 tons of spinach, lettuce, choy sum and other leafy green vegetables per day, with products mainly exported to Southeast Asia and the Hong Kong-Macau markets. The enterprise had long faced two core pain points: first, traditional cold-room precooling required 4–8 hours, which could not match the time requirements of early-morning harvesting and same-day shipment; second, air-cooled precooling caused a vegetable dehydration rate of 6%~10%, resulting in wilted leaves and degraded appearance, and the products were often downgraded during export inspection due to failing to meet freshness standards. In early 2025, the enterprise decided to introduce vacuum precooling technology to upgrade its production line. After extensive investigation and equipment testing, it selected the Yuanxian Machinery CVF-3000A-6P Fruit and Vegetable Vacuum Precooler as its core precooling equipment.
II. Equipment Configuration and Technical Parameters
2.1 Equipment Selection
The CVF-3000A-6P is a batch-type fruit and vegetable vacuum precooler with a single-batch processing capacity of 3000 kg and a daily processing capacity of 15–20 tons (depending on batch turnover rhythm). The main body of the equipment adopts a professionally designed pressure-bearing steel structure, and the control system is a PLC fully automatic touch screen that supports preset multi-stage process parameters.
2.2 Core Technical Parameters
| Parameter | Value |
|---|---|
| Chamber volume | 24 m³ |
| Processing capacity per cycle | 3000 kg |
| Processing time per cycle | 30–40 minutes |
| Cooling capacity | 76 kW |
| Operating power | ~84 kW |
| Compressor | Hanbell screw |
| Vacuum pump set | Dalutong 7.5kW*2 + 7.5kW |
| Ultimate vacuum level | ≤600 Pa |
| Dehydration rate | 1.0%~2.0% |
| Power supply | 380V/50Hz/3P |
| Equipment weight | ~7800 kg |
| Door system | Manual sliding door |
| Dimensions | L10500 × W2200 × H2600 mm |
2.3 Process Support
The equipment is equipped with a chiller unit and a closed-circuit cooling tower, with the cooling water temperature stably controlled below 10°C; the vacuum system adopts a Roots pump + rotary vane pump two-stage evacuation structure to ensure rapid establishment of the vacuum environment. The packaging stage is connected to an automated weighing-packaging line, enabling completion of sealing and transfer into the cold room within 30 minutes after precooling, forming a complete closed loop for repairing cold-chain breakpoints.
III. Actual Operating Data and Results
3.1 Precooling Efficiency Comparison
After 6 months of operation at the enterprise, the measured data are as follows:
| Dimension | Traditional cold-room air cooling | Vacuum precooling (CVF-3000W-6P) | Improvement |
|---|---|---|---|
| Precooling duration | 4–8 h | 25–35 min | Efficiency increased by about 10–15 times |
| Core temperature drop | 25°C→6°C (average 6h) | 25°C→3°C (average 28min) | — |
| Dehydration rate | 5%~8% | 1.8%~2.5% | Reduced by about 60% |
| Unit energy consumption | 24–30 kWh/ton | 10–12 kWh/ton | Energy savings of about 50%~60% |
| Taking spinach as an example: it was loaded into the machine for precooling within 1 hour after harvest, and after 28 minutes the core temperature dropped to 3.2°C, with a dehydration rate of only 2.1%; the leaves remained upright with fresh green color, and there was no mechanical damage or freezing injury. The precooling effect on lettuce was even better, with the dehydration rate controlled at 1.5%~1.8%, superior to the export standard requirement of less than 3%. |
3.2 Quality and Shelf Life
Third-party testing data show that, under 2–4°C cold-chain storage and transportation conditions, the shelf life of leafy vegetables after vacuum precooling was extended by 5–7 days compared with traditional air cooling. Among them, the freshness period of spinach was extended from 5 days to 8 days, and that of choy sum from 4 days to 9 days, greatly reducing the terminal loss rate. The pass rate of sampling inspections for export customs clearance increased from 92% to 98.5%.
IV. Operational Feedback and Evaluation
Feedback from the enterprise’s production manager:
“Going from a 4-hour wait to completing precooling within half an hour has completely changed the entire production rhythm. Previously, harvested vegetables queued at the cold-room entrance; now they are processed as soon as they arrive, and the production line flow efficiency has improved very noticeably.” Evaluation from the quality control department: “The greatest value of vacuum precooling is that it locks in the fresh state of vegetables right after harvest. The dehydration rate has dropped from 8% to 2%, and the leafy vegetables are still crisp and bright when they reach customers. For export quality, this is core competitiveness.” Records from the equipment operation and maintenance department: The equipment ran continuously for 6 months, cumulatively processing about 2700 tons of vegetables. The vacuum pump set operated smoothly, and there was no problem of vacuum level decline caused by excessively high moisture content. Routine maintenance only requires changing the vacuum pump oil and cleaning the condenser fins every two weeks, and the mean time between failures (MTBF) of a single machine exceeds 2000 hours. The PLC control system supports remote diagnostics, and the production management team can view the precooling temperature curve of each batch in real time via mobile phone. Summary: The application of the CVF-3000W-6P vacuum precooler at this enterprise verified the significant advantages of vacuum precooling technology in leafy vegetable processing — efficiency increased by an order of magnitude, quality was comprehensively optimized, and costs were effectively reduced. This project provides a reference example for the standardized upgrading of cold-chain pre-treatment at leafy vegetable export enterprises.
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