vacuum control on a freeze dryer(SJ creator S and Command Freeze Dryers)

Intelligent Dual Inlet Vacuum Control (Bleed-in Control)

The freeze dryer is equipped with an intelligent dual inlet (bleed-in) valve vacuum control system, consisting of a large inlet valve and a small inlet valve.

The system automatically selects the appropriate valve combination according to the vacuum setpoint, ensuring stable, precise, and smooth vacuum regulation throughout the freeze-drying process.

Operating logic:

• Low pressure range (high-precision control)

  When the vacuum setpoint is high (e.g. ≤ 15 Pa),

  👉 only the small inlet valve is activated for fine and accurate pressure adjustment.

• Medium pressure range (balanced control)

  When the vacuum setpoint is within an intermediate range (e.g. 15–50 Pa),

  👉 the large inlet valve is activated to achieve faster regulation while maintaining stability.

• High pressure range (fast response control)

  When the vacuum setpoint is low (e.g. ≥ 50 Pa),

  👉 both the large and small inlet valves are activated simultaneously to provide rapid and stable vacuum control.

Advantages:

• Smooth and stable vacuum regulation
• High control accuracy at low pressure levels
• Reduced vacuum pump load and extended pump lifetime
• Ideal for different stages of the freeze-drying process

In simple terms:

Small valve for precision, large valve for speed, and both valves for rapid response.