There are significant differences in structure, performance, and application between the two blade Roots blower and the three blade Roots blower. The following is a detailed comparative analysis:
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**1、 Core structural differences**
|* * Comparison item * * | * * Two blade Roots blower * * | * * Three blade Roots blower * *|
|------------------|----------------------------------|----------------------------------|
|* * Number of impellers * * | 2 straight or involute impellers | 3 spiral twisted blade impellers|
|* * Impeller shape * * | Simple straight line/involute profile | Complex helical surface (usually 45 ° or 60 ° twist angle)|
|* * meshing method * * | 180 ° phase difference rigid meshing | 120 ° phase difference flexible meshing|
|* * Gear load * * | High (concentrated impact force) | Low (uniform force)|
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**2、 Performance parameter comparison**
|* * Parameters * * | * * Two leaf type * * | * * Three leaf type * * | * * Advantages and disadvantages analysis * *|
|------------------|--------------------------------|--------------------------------|-------------------------------|
|Flow pulsation rate * * | 8~12 | 3~5 | Three leaf airflow is smoother|
|* * Noise level * * | 85~95 dB (A) | 75~85 dB (A) | Three leaf noise reduction of more than 10dB|
|* * Volumetric efficiency * * | 50~65 | 65~75 | Three leaf leakage reduction of 20|
|* * Pressure * * | ≤ 98 kPa (conventional) | ≤ 98 kPa (high-pressure type can reach 147 kPa) | Three leaf type has stronger adaptability to high pressure|
|* * Axial force fluctuation * * | Large (periodic impact) | Small (good balance) | Three bladed bearings have a longer lifespan|
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**3、 Differences in operational characteristics**
1. Airflow characteristics**
-* * Two leaf type * *:
-The airflow pulse is obvious, presenting a periodic "burst" sound
-Suitable for scenarios that are insensitive to pulsation (such as material conveying)
-* * Three leaf type * *:
-The airflow is continuous and stable, approximately laminar
-Suitable for precision gas supply (such as sewage treatment aeration)
2. Vibration and Wear**
-Due to force imbalance, the bearing wear rate of the two bladed type is 30-50% faster than that of the three bladed type
-The three bladed spiral impeller can reduce backflow impact and increase gear life by 2-3 times
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**4、 Comparison of Manufacturing Costs**
|* * Cost Item * * | * * Two Leaf Type * * | * * Three Leaf Type * *|
|------------------|--------------------|--------------------|
|Impeller machining | Simple (turning/milling) | Complex (CNC forming)|
|Material utilization rate | High (less waste) | Low (surface processing loss)|
|Assembly accuracy requirements | ± 0.1mm | ± 0.05mm|
|Market average price | Low (15-20 cheaper) | High (20-30 more expensive)|
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**5、 Typical application scenarios**
|* * Scenario * * | * * Recommended Type * * | * * Reason * *|
|------------------|-------------------|-----------------------------------|
|Pneumatic conveying (granules) | Two blade type | Wear resistant, pulsation does not affect the conveying effect|
|Sewage treatment aeration | Three leaf type | Requires stable airflow and low noise|
|Vacuum packaging | Three leaf type | High vacuum requirement (up to -80kPa)|
|Blast furnace blowing | Two blade type (high-pressure version) | Simple structure, high temperature resistance|
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**6、 Selection suggestions**
1. * * Prioritize the three leaf type * *:
-Sensitive to noise (such as near residential areas)
-High pressure required (>78.4kPa)
-Long term continuous operation condition
2. * * Optional Two Leaf Type * *:
-Limited budget and extensive working conditions
-The medium contains hard particles (the impeller is more wear-resistant)
-High requirements for intermittent operation and maintenance convenience
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**7、 Maintain differences**
|* * Maintenance Item * * | * * Two Leaf Type * * | * * Three Leaf Type * *|
|------------------|----------------------------|----------------------------|
|Adjustment cycle of impeller clearance | 6-12 months | 12-18 months|
|Gear replacement frequency | 2-3 years (impact wear) | 4-5 years (uniform wear)|
|Bearing lubrication requirements | Add grease every 1500 hours | Add grease every 2000 hours|
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**Summary: The three leaf type has obvious advantages in energy efficiency, noise, and lifespan, but the two leaf type is more prominent in terms of cost and pollution resistance. The specific selection needs to be balanced based on the working condition requirements, budget, and maintenance capabilities.
