Roots blower belongs to a special type of ventilation fan, but there are significant differences in technical principles, performance characteristics, and application scenarios compared to conventional ventilation fans. The following analysis is conducted from three dimensions: classification attribution, technical comparison, and application scenarios to clarify its relationship with ventilation fans:
1、 Classification: Roots blower belongs to the volumetric subdivision type of ventilation fan
Classification system for ventilation fans
According to the "Classification and Model Compilation Method for Fans" (GB/T 3235-2008), ventilation fans are divided into two categories based on their working principles:
Blade type ventilation fan: By rotating the blades to change the kinetic energy and pressure of the gas (such as centrifugal fans, axial fans), it is suitable for low-pressure and high flow conditions.
Positive displacement ventilation fan: It transports gas by periodically changing the chamber volume (such as Roots blower, screw blower), suitable for medium and high pressure low flow scenarios.
Positioning of Roots blower
The Roots blower belongs to the rotary volumetric branch of the positive displacement ventilation fan, which uses two synchronously rotating rotors to squeeze gas for transportation, forming a technological complementarity with the blade type ventilation fan.
2、 Technical Comparison: Core Differences between Roots Fans and Conventional Ventilators
Comparison dimension Roots blower conventional ventilation fan (centrifugal/axial flow)
Working principle: Volume rotary compression (forced air supply), blade kinetic energy conversion (centrifugal acceleration/axial flow guidance)
High pressure (0.05-01MPa, some may be higher) and low pressure (<0.05MPa) within the pressure range
Flow stability is almost unaffected by outlet pressure (constant flow characteristic). Flow decreases with increasing pressure
Efficiency characteristics: High efficiency under low pressure conditions (>70), and the high pressure efficiency attenuation zone is concentrated near the design point
The structural complexity of the rotor clearance is precise (0.1mm level), and lubrication is required. The sealing blades are prone to wear and require regular maintenance
The noise level is mainly mechanical noise (>85dB) and aerodynamic noise (<80dB)
3、 Application scenario: Differentiated division of labor between Roots blower and ventilation fan
Typical application of Roots blower
Pneumatic conveying: conveying granular materials such as grain and cement (requiring medium and high pressure to overcome pipeline resistance).
Aquaculture oxygenation: forced air supply to ensure high-density aquaculture dissolved oxygen (stable flow demand).
Industrial aeration: Sewage treatment aeration tank (requires constant air flow to maintain microbial activity).
Vacuum adsorption: Printing and packaging industries (requiring stable negative pressure environment).
Typical applications of conventional ventilation fans
Building ventilation: exhaust from subways and tunnels (requiring high flow and low pressure).
Industrial cooling: Boiler and kiln heat dissipation (centrifugal fan high pressure scenario).
Air conditioning system: Central air conditioning fresh air delivery (axial flow fan for long-distance air supply).
4、 Conclusion: Positioning of the relationship between Roots blower and ventilation fan
Technical essence: Roots blower is a positive displacement ventilation fan with forced air supply characteristics, belonging to the same category of ventilation fans as blade type ventilation fans, but with a different technical route.
Selection principle:
Priority should be given to Roots blowers: for scenarios requiring medium to high pressure (>0.05MPa), constant flow rate, and small volume.
Prioritize conventional ventilation fans: for scenarios that require high flow, low pressure, and noise sensitivity.
Industry trend: With the application of technologies such as magnetic levitation and air bearings, Roots blowers are gradually upgrading towards low-noise direction, and the application boundary with blade ventilators will be further clarified.
Summary: Roots blower is the representative of "high-pressure constant flow" in the ventilation fan family. Its technical characteristics make it irreplaceable in fields that require forced air supply, stable flow, and medium to high pressure output. Conventional ventilation fans are more suitable for low-pressure and high flow scenarios. Although both belong to the same category of ventilation fans, there are significant differences in their technical routes and application scenarios, and selection should be based on specific working conditions.
