In industrial production, although multi-stage blowers and vacuum blowers belong to the same gas conveying equipment, there are significant differences in their working principles and application scenarios. This article will compare the technical characteristics and application value of the two from multiple dimensions.

1. Working principle

Multi stage blower: By connecting multiple impellers in series, the air is gradually pressurized. After being sucked in through the air inlet, it is accelerated by the impellers, decelerated by the diffuser, and finally outputs high-pressure airflow. Its core function is to pressurize and transport gas.

Vacuum fan: Based on the principle of centrifugation or vortex, negative pressure is generated, and a vacuum environment is formed by high-speed rotation of the impeller to extract gas from a closed space. Its essence is to reduce pressure and achieve suction function.

2. Pressure characteristics

Multi stage blowers can provide continuous positive pressure output (usually 0.5-5 bar), suitable for processes that require high-pressure airflow (such as pneumatic conveying, aeration tank oxygenation).

Vacuum fans achieve efficient suction by reducing local air pressure (with a vacuum degree of up to -90kPa), and are commonly used for exhaust gas suction, material recovery, or vacuum packaging.

3. Structural design

The multi-stage blower adopts a multi-stage impeller series structure, with smooth flow channels to reduce energy loss. The casing needs to withstand high pressure and is designed to be relatively heavy.

Vacuum fans are mostly designed as single-stage or two-stage, emphasizing the balance between vacuum degree and suction volume. The shell structure needs to adapt to negative pressure conditions, and the sealing requirements are higher.

4. Application scenarios

Multi stage blower: fields that require high-pressure airflow, such as pneumatic conveying (grain, chemical powder), sewage treatment (aeration and oxygenation), industrial dust removal, etc.

Vacuum fan: used in pharmaceutical industry (material vacuum drying), food packaging (vacuum sealing), semiconductor manufacturing (vacuum reaction) and other scenarios that require negative pressure operation.

5. Energy consumption and noise

Blowers generally consume more energy than vacuum fans due to their continuous compression of gas, but their efficiency is higher under high-speed conditions.

Vacuum fans have lower efficiency at low flow rates and high pressure differentials, but their noise control is usually better than that of blowers (due to optimized sealing design).

6. Key points for purchasing

The selection of blower should pay attention to flow rate, air pressure, and medium density to ensure that it meets the requirements of conveying distance and resistance.

Vacuum fans need to calculate the vacuum degree, pumping rate, and balance sealing and corrosion resistance (such as handling corrosive gases).

Conclusion

Multi stage blowers and vacuum blowers have their own focuses, and should be selected differently when the process requirements are clear. Only by understanding their core differences can we match the optimal equipment for enterprise production.