Dry screw vacuum pumps are revolutionizing industrial processes by offering high vacuum performance, energy efficiency, and eco-friendly operation. This article explores their working principles, structural advantages, and applications across industries like oil and gas recovery, biomedicine, and food processing. Additionally, it provides actionable insights for buyers on selecting and maintaining these pumps, ensuring long-term reliability and sustainability.
1. Introduction to Screw Vacuum Pumps
1.1 Working Principle
A dry screw vacuum pump operates using two parallel screw rotors that rotate synchronously at high speeds in opposite directions. These rotors and the pump housing form multiple sealed chambers, which continuously transport gas from the inlet to the outlet without compression. This design eliminates the need for lubricating oil, ensuring a clean vacuum environment.
This requires that the entire product must be the highest standard from material selection to processing. Because the clearance between components is required to be very small, it is necessary to ensure that the screw and pump body materials are not easy to deform, especially when the temperature changes to a certain value, the locking phenomenon cannot occur due to deformation. Special material treatment shall be selected to ensure the fine processing of all parts. In addition to the fine processing of the two screws, dynamic balance correction shall be carried out. The shaft end bearing must be a high-quality special bearing, which not only ensures the parallelism of the screw rotor and is not prone to slight displacement, but also ensures smooth rotation and is not affected by temperature and other factors.
When the vacuum pump is working, the clearance between them is small without friction, the operation is stable, the vibration is small. the noise is low. the energy is saved, and the service life is extended. The special screw structure can continuously promote the air flow without compression. The exhaust port is lower than the screw position, the liquid discharge capacity is strong, and it is easy to clean. The pump cavity has short channels, no partitions, and the exhaust and discharge are smooth, so the working efficiency is high, the suction is super strong, and the limit vacuum degree of the pump is greatly improved. It can provide high vacuum 5Pa or even close to 1Pa; There is no lubrication and pollution in the working chamber, which can provide a clean vacuum without worrying about backflow pollution. Extracts can also be directly recycled or discharged without environmental pressure.
1.2 Structure and Design
Key components include precision-engineered screw rotors, synchronizing gears, and corrosion-resistant materials (e.g., titanium, stainless steel). The pump’s compact design features short gas pathways, no internal partitions, and an exhaust port positioned below the screws to enhance liquid discharge efficiency.
2. Advantages of Dry Screw Vacuum Pumps
2.1 Environmental and Efficiency Benefits
- Oil-Free Operation: No lubricants are required, preventing contamination of extracted media and enabling direct recycling of gases or liquids.
- Energy Savings: Variable-pitch screw designs reduce power consumption by up to 30% compared to traditional pumps.
- Low Noise: Advanced dynamic balancing of rotors ensures vibration-free operation with noise levels below 75 dB(A).
2.2 High Vacuum Performance
These pumps achieve an ultimate vacuum of ≤1 Pa, making them ideal for high-vacuum applications such as semiconductor manufacturing and vacuum coating. Their robust suction capacity (up to 1,800 m³/h in water-cooled models) ensures rapid evacuation even in demanding environments.
2.3 Material and Anti-Corrosion Design
Critical flow-path components are crafted from corrosion-resistant materials like nano-ceramics or NIP alloy coatings. Optional automatic purging systems further protect against dust and condensable gases, extending the pump’s lifespan.
3. Applications in Various Industries
3.1 Oil and Gas Recovery
Dry screw pumps excel in hydrocarbon vapor recovery systems, ensuring zero leakage and compliance with environmental regulations. Screw vacuum pumps are widely used in oil and gas recovery applications, including: recovering volatile organic compounds during petroleum storage and transportation (e.g., oil depots, gas stations, and tanker loading/unloading) to minimize evaporation losses; treating volatile gases from reactors and storage tanks in chemical production to prevent leakage and pollution; and integrating with condensation units in oil-gas condensation recovery systems to convert gaseous hydrocarbons into liquid form for reuse.
3.2 Biomedical and Pharmaceutical
Their oil-free design prevents cross-contamination, making them suitable for sterile processes like lyophilization and solvent recovery.
3.3 Food Processing
These pumps handle humid and dusty gases efficiently, supporting applications such as vacuum packaging and dehydration. Screw vacuum pumps play a vital role in food preservation through key applications such as vacuum packaging—removing air from packaging to inhibit microbial growth and extend the shelf life of meats, seafood, and cheeses; freeze-drying (lyophilization)—sublimating moisture under vacuum to retain nutritional value and texture in products like coffee, dried fruits, and health supplements; modified atmosphere packaging (MAP)—replacing air with gas mixtures (e.g., N, CO) after vacuuming to preserve food color and freshness; and enhancing production line efficiency via vacuum adsorption systems integrated into filling and sealing equipment.
4. Purchasing Considerations
4.1 Technical Parameters
- Pumping Speed: Select models based on required flow rates (e.g., 5–1,800 m³/h).
- Pressure Limit: Ensure the pump meets the desired vacuum level (≤1 Pa for high-precision tasks).
- Cooling Options: Choose between air-cooled (low maintenance) and water-cooled (high-capacity) variants.
4.2 Brand and Quality Assurance
Opt for pumps with internationally certified components, such as SKF/NSK bearings and German-engineered seals, to guarantee durability.
5. Maintenance and Operational Tips
5.1 Routine Maintenance
Inspect Seals and Bearings: Check monthly for wear and tear.
Clean Filters: Replace inlet filters every 500 operating hours to prevent clogging.
Monitor Cooling Systems: Ensure consistent water flow in water-cooled models to avoid overheating.
5.2 Troubleshooting Common Issues
Excessive Vibration: Rebalance rotors or replace worn bearings.
Reduced Vacuum Level: Check for leaks in the inlet/outlet connections or damaged shaft seals.
Conclusion
Dry screw vacuum pumps combine cutting-edge engineering with environmental sustainability, making them indispensable in modern industry. By prioritizing quality components and adhering to maintenance best practices, businesses can maximize efficiency while minimizing operational costs.
