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 | www.vacuum-fresh.com