Roots blower is a type of volumetric gas conveying equipment that uses a pair of interlocked rotors to forcibly push gas and achieve constant flow conveying. Its name comes from the inventor Roots Brothers in the United States. Here is the explanation:
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**1、 Core working principle**
1. * * Structural composition**
-* * Dual rotor * *: Two blade or three blade spiral rotor (gap 0.1-0.3mm)
-* * Synchronous gear * *: Ensure non-contact reverse rotation of the rotor
-* * Shell * *: Cast iron/stainless steel enclosed chamber
2. * * Working process**
-The rotor rotates to form a closed chamber → gas is pushed from the inlet to the outlet → * * no internal compression * *, pressure is established by system resistance
3. * * Characteristic curve**
-* * Constant flow rate * *: proportional to the rotational speed, almost unaffected by pressure
-Pressure range: 9.8-98 kPa (0.1-1.0 bar)
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**2、 Core application areas**
**1. Environmental Protection Engineering**
-Sewage treatment aeration: providing oxygen for activated sludge (gas demand 0.5-1.5 Nm3/ton of sewage · minute)
-* * Biogas Boosting * *: Transporting anaerobic fermentation gas to the generator set
**2. Industrial production**
-* * Pneumatic conveying * *: Pipeline conveying of cement, flour and other powders (wind speed 15-25 m/s)
-* * Vacuum packaging * *: achieve negative pressure of -20~-50 kPa with vacuum pump
**3. Special Scene**
-Aquaculture: bottom oxygenation of fish ponds (dissolved oxygen ≥ 5 mg/L)
-Chemical process: Transportation of hazardous gases such as chlorine and hydrogen (requiring explosion-proof design)
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**3、 Compared to other fans**
|* * Features * * | Roots blower | Centrifugal blower | Screw blower|
|----------------|-------------------------|-----------------------|-----------------------|
|* * Flow regulation * * | Only capable of variable frequency speed regulation | Adjustable valve/speed | Combined regulation of variable frequency and slide valve|
|Efficiency * * | 60-75 | 70-90 | 75-85|
|* * Noise * * | 85-100 dB (A) | 70-85 dB (A) | 65-80 dB (A)|
|* * Maintenance cost * * | Low (only for gears/bearings) | Medium (requires dynamic balancing) | High (requires high screw accuracy)|
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**4、 Key parameters for selection**
1. * * Airflow Calculation**
$$
Q=\ frac {V \ times N} {1000} \ quad (V=displacement per revolution, L/r; N=rotational speed, rpm)
$$
-Example: -100 type (V=6.9 L/r, N=1450 rpm) → Q ≈ 10 m3/min
2. * * Pressure matching**
-To cover: pipeline resistance+liquid level pressure+equipment pressure loss
-Excess: ≥ ten
3. * * Special Needs**
-Corrosive gas: 316L stainless steel rotor+PTFE seal
-Food grade: Oil free design+polished stainless steel shell (Ra ≤ 0.8 μ m)
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**5、 Key points of operation and maintenance**
1. * * Daily inspection**
-Gear oil level (replenished every 500 hours)
-Bearing temperature (≤ 85 ℃)
2. * * Critical Maintenance**
-Adjustment of rotor clearance (every 8000 hours)
-Cleaning of muffler filter (when pressure difference>300Pa)
3. * * Operation strictly prohibited**
-Overpressure operation (requiring valve protection)
-Long term idling (without lubrication cooling)
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**6、 Market product reference**
|Brand * * | Typical model | Flow rate (m3/min) | Price (10000 yuan) | Features|
|------------|---------------|--------------|------------|-----------------------|
|| -150 | 15-40 | 5-8 | Three leaf low vibration|
|Delta Blower | 20-100 | 25-60 | Technology, Energy Efficiency|
|BSR-80 | 8-25 | 3-5 | Economical and easy to maintain|
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**Summary * *:
Roots blower is an ideal choice for medium to low pressure constant flow conveying, especially suitable for process scenarios that require stable air flow (such as aeration and pneumatic conveying). When selecting, special consideration should be given to the characteristics of the medium, pressure requirements, noise control, and regular maintenance to ensure a lifespan (usually 8-10 years). For high pressure (>1 bar) or ultra clean demand, it is recommended to evaluate alternative solutions for screw fans or centrifugal fans.
