The performance indicators of a two blade Roots fan are key parameters for measuring its working efficiency, applicability, and reliability, mainly including the following categories:
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**1. Basic performance parameters**
|* * Indicator * * | * * Explanation * * | * * Typical Range (Two Leaf Fan) * *|
|------------------|-------------------------------------------------------------------------|----------------------------------|
|Airflow (Q) | Volume of gas transported per unit time (m3/min or m3/h) | 0.5~200 m3/min (common small models)|
|* * Pressure (P) * * | Static pressure difference between outlet and inlet (kPa, Bar, or mmHg) | 9.8~98 kPa (0.1~1.0 Bar)|
|* * Speed (n) * * | Rotor rotation speed (rpm), affecting air volume and noise | 500~3000 rpm|
|* * Power (N) * * | Rated power of motor (kW), determines energy consumption | 0.75~200 kW|
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**2. Efficiency and energy consumption indicators**
|* * Indicator * * | * * Explanation * *|
|------------------------|-------------------------------------------------------------------------|
|* * Volumetric efficiency * * | The ratio of actual air volume to theoretical air volume (usually lower for two bladed fans, about 70-85)|
|* * Specific power * * | The power required per unit air volume (kW/(m3/min)) is 10-20 higher for a two bladed fan than for a three bladed fan|
|* * Adiabatic efficiency * * | Measuring energy conversion efficiency, the efficiency of a two blade fan is usually ≤ 60 due to leakage and pulsation losses|
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**3. Dynamic performance indicators**
|* * Indicator * * | * * Explanation * *|
|------------------------|-------------------------------------------------------------------------|
|* * Airflow pulsation rate * * | Outlet pressure fluctuation amplitude (significant pulsation of the two blade fan, up to ± 10 or more)|
|* * Noise level * * | Sound pressure level at a distance of 1 meter from the fan (typically 75-95 dB (A) for a two bladed fan, 5-10 dB higher than a three bladed fan)|
|Vibration velocity * * | Shell vibration value (usually ≤ 4.5 mm/s for two blade fans, vibration reduction measures need to be strengthened)|
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**4. Structural parameters**
|* * Indicator * * | * * Explanation * *|
|------------------------|-------------------------------------------------------------------------|
|* * Rotor clearance * * | Blade to shell clearance (usually 0.15~0.25 mm for two blade fans, too large can cause leakage, too small can cause wear)|
|* * Import and export diameter * * | Flange diameter (DN50~DN300), to match the pipeline|
|Weight * * | Overall weight of the machine (the two blade fan is 5-15 times lighter than the three blade fan of the same specification)|
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**5. Environmental adaptability indicators**
|* * Indicator * * | * * Explanation * *|
|------------------------|-------------------------------------------------------------------------|
|The medium temperature is usually ≤ 80 ℃ (special sealing is required for high temperatures)|
|* * Protection level * * | Motor IP54/IP55 (dustproof and splash proof)|
|* * Allowable particle concentration * * | ≤ 150 mg/m3 (dust containing gas needs to be filtered)|
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**6. Reliability index**
|* * Indicator * * | * * Explanation * *|
|------------------------|-------------------------------------------------------------------------|
|* * Bearing life * * | Due to high vibration, the bearing life of a two bladed fan is usually ≤ 20000 hours (three bladed fans can reach 30000 hours)|
|* * Gear life * * | Lubricating oil replacement cycle is 500 hours (first time), followed by 3000 hours|
|* * Shaft seal life * * | The mechanical seal or oil seal life is about 6-12 months (requires regular inspection)|
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**Comparison of performance between two leaves and three leaves**
|* * Indicator * * | * * Two blade Roots blower * * | * * Three blade Roots blower * *|
|------------------|----------------------------------------|----------------------------------------|
|Pulsation * * | High (low frequency, large amplitude) | Low (high frequency, small amplitude)|
|* * Noise * * | 75~95 dB (A) | 70~85 dB (A)|
|* * Efficiency * * | Low (Volumetric Efficiency 70-85) | High (Volumetric Efficiency 80-90)|
|* * Maintenance frequency * * | High (vibration/wear fast) | Low|
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**Selection suggestions**
1. * * Priority Three Leaf Fan * *: Unless budget constraints or compatibility with old equipment, three leaf fans are superior in efficiency, noise, and maintenance costs.
2. * * Two leaf applicable scenarios * *: low-frequency intermittent work, insensitive to pulsation (such as simple pneumatic conveying).
3. * * Key parameter matching * *: Select the model based on the actual required air volume, pressure, and noise limits.
If specific model performance curves are required, please refer to the * * air volume pressure power characteristic diagram * * provided by the manufacturer.
