Applications of Water Ring Vacuum Pumps in the Pharmaceutical Industry

Water ring vacuum pumps are widely used in the pharmaceutical industry due to their oil-free operation, simple structure, and strong corrosion resistance. They play a critical role in the following applications:

1. Key Applications

(1) Vacuum Drying (Lyophilizers/Ovens)

Purpose:

Lyophilization (Freeze Drying): Used for dehydrating heat-sensitive drugs such as vaccines, antibiotics, and biologics while preserving their efficacy.

Vacuum Ovens: Removing residual solvents (e.g., ethanol, acetone) from active pharmaceutical ingredients (APIs).

Role of the Pump:

Provides a vacuum environment of -0.09 to -0.098 MPa, lowering the boiling point of water for rapid low-temperature drying.

(2) Solvent Recovery & Distillation

Purpose:

Extraction of traditional Chinese medicine or recovery of organic solvents (e.g., methanol, dichloromethane).

Role of the Pump:

Reduces system pressure, enabling solvent evaporation at lower temperatures, saving energy and preventing thermal degradation.

(3) Sterile Filtration & Filling

Purpose:

Sterile filtration (0.22 μm membrane) of injectables/vaccines and bubble removal before filling.

Role of the Pump:

Delivers oil-free vacuum to prevent contamination (compliant with GMP standards).

(4) Fermentation Processes

Purpose:

Maintaining slight negative pressure in bioreactors to ensure uniform oxygen distribution and CO₂ removal.

Role of the Pump:

Corrosion-resistant materials (e.g., 316L stainless steel or PTFE-lined) withstand acidic fermentation broths.

(5) Packaging Degassing

Purpose:

Vacuum sealing of blister packs (aluminum-plastic) to prevent drug oxidation.

2. Advantages in Pharmaceutical Applications

Advantage

Pharmaceutical Value

Oil-Free Operation    Eliminates lubricant contamination.    

Corrosion Resistance    Wetted parts available in PP, PVDF, or 316L stainless steel, resistant to acids and solvents.    

Low Noise/Vibration    Suitable for cleanroom environments (noise levels typically ≤75 dB).    

Easy Maintenance    No complex seals; only requires periodic water ring fluid replacement (if using standard models).    

Sterilizable Design    Some models support CIP (Clean-in-Place) or SIP (Steam-in-Place) for sterile production.    

3. Key Selection Criteria

Vacuum Level: Typically -0.09 to -0.1 MPa (absolute pressure: 10–100 mbar).

Flow Rate: Depends on equipment scale (e.g., 20–200 m³/h for lyophilizers).

Materials:

PP/PVDF: For strong acids (e.g., HCl) or organic solvents (e.g., acetone).

Stainless Steel 316L: For high-temperature or high-hygiene applications.

Certifications: Must comply with GMP, ISO 13485 (medical devices), etc.

4. Typical Supporting Equipment

Lyophilizers: Water ring pumps serve as primary vacuum pumps, often paired with Roots pumps.

Rotary Evaporators: For small-scale solvent concentration in labs.

Aseptic Filling Lines: Removes air bubbles from drug solutions before filling.

5. Important Considerations

Contamination Prevention:

Install sterile air filters (0.1 μm) at the intake to prevent microbial backflow.

Liquid Ring Fluid Management:

Use purified water or anticorrosive additives; closed-loop systems (e.g., glycol-water mix) minimize contamination risks.

Alternatives:

For higher vacuum needs (e.g., molecular distillation), combine with dry screw pumps or claw pumps.

Conclusion

Water ring vacuum pumps are essential in pharmaceutical processes such as drying, distillation, filtration, and fermentation, thanks to their oil-free and corrosion-resistant design. When selecting a pump, prioritize material compatibility, vacuum performance, and regulatory compliance to ensure seamless integration with critical equipment like lyophilizers.