Vacuum System: Two Orders of Magnitude Apart
| Parameter | CVD Freeze Dryer | CVF Vacuum Cooler |
|---|---|---|
| Working pressure | 10–15 Pa | 600–660 Pa |
| Pump config | Roots + rotary vane (2-stage) | Water ring + rotary vane |
| Leak rate req. | ≤0.02 Pa·m³/s | ≤0.5 Pa·m³/s |
| Pump-down time | 12–20 min to 13 Pa | 3–6 min to 660 Pa |
| Oil change | 500–800h (fruit) | 2000–3000h |
Refrigeration System: Cooling vs Freezing
| Component | CVD Freeze Dryer | CVF Vacuum Cooler |
|---|---|---|
| Cold trap temp | -40 to -65°C | -5 to -10°C |
| Compressor type | Two-stage piston/screw/cascade | Single-stage scroll (R404A) |
| Heating shelves | Yes — silicone oil circulation | No — empty chamber |
| Bitzer model (same capacity) | 6HSS-8Y (two-stage) | 4PCS-12.2 (single) |
A freeze dryer cold trap needs -55 to -65°C to handle high-eutectic materials (aloe -40°C, banana -55°C). This requires two-stage compression or cascade refrigeration (R404A + R23, the latter reaching -75°C). A vacuum cooler only needs -10°C — a single-stage scroll compressor handles it easily.
Chamber Structure: Shelves vs Empty Cavity
| Aspect | CVD Freeze Dryer | CVF Vacuum Cooler |
|---|---|---|
| Interior | Multi-layer heated shelves | Empty box |
| Loading | Trays on shelves (thin layer) | Cart-pushed or bulk |
| Door seals | Dual O-ring + heated door frame | Single silicone gasket |
| Insulation | 80–100mm polyurethane | 20–30mm polyurethane |
Control System: Pressure Control vs Temperature Curve
| Feature | CVD Freeze Dryer | CVF Vacuum Cooler |
|---|---|---|
| Control mode | Temp curve + pressure setpoint | Pressure only |
| Cycle time | 12–28 hours | 10–25 minutes |
| Recipe programming | 10+ segments | Single setpoint |
| Endpoint detection | Pressure rise test | Core temp probe |
Real Case: Same Mushroom, Different Equipment
| Application | Equipment | Cycle | Product Form | Shelf Life | Value/kg |
|---|---|---|---|---|---|
| Fresh delivery | CVF-1000 pre-cooler | 35 min | Whole, wet | 8–12 days | Lower |
| Deep processing | CVD-1000 freeze dryer | 18 h | Slices/powder | 24 months | 5–10× |
Selection Advice
- Shipping today → CVF vacuum cooler. 10–25 min per cycle, retains moisture.
- Long-term storage → CVD freeze dryer. 12–24 h per cycle, transforms to shelf-stable.
- Need both → Buy two machines. Different tools for different jobs.
Yuanxian Machinery | vacuum-fresh.com