The selection of Roots blower requires comprehensive consideration of multiple parameters and application scenarios. The following are detailed selection steps and precautions:
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**1. Determine basic parameters**
-Flow rate (air volume)**
The unit is usually m3/min or m3/h, determined according to process requirements. Need to consider:
-Actual demand flow (reserve 10-20 margin to prevent fluctuations in operating conditions).
-Flow rate under standard conditions (temperature 20 ℃, pressure 101.3kPa) or operating conditions.
-Pressure (wind pressure)**
The unit is kPa or bar, which refers to the pressure difference (* * static pressure * *) between the outlet and inlet of the fan. Calculate the system resistance (pipes, valves, equipment, etc.) and reserve 5-10 margins.
-* * Medium characteristics**
-Clean air and special gases (such as biogas and corrosive gases) need to be specified.
-Temperature: High temperature gases should be selected with high-temperature resistant models or equipped with cooling systems.
-Dust content: If dust is present, a filter or wear-resistant design should be installed.
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**2. Select fan model**
-Check the performance curve based on flow and pressure**
The performance curve of the Roots blower (provided by the manufacturer) can match the required flow rate and pressure, ensuring that the operating point is within the zone (usually the middle zone of the curve).
-* * Speed selection**
High speed fans have a small volume but produce loud noise and wear out quickly; Low speed fans have a long lifespan but a large volume. Balancing noise, lifespan, and spatial limitations is necessary.
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**3. Motor power calculation**
-Theoretical power formula:
\[
P = \frac{Q \times \Delta P}{60 \times \eta} \times K
\]
-(Q): Flow rate (m3/min)
-\ (\ Delta P \): Differential pressure (kPa)
-(eta): Fan efficiency (usually 0.6~0.8)
-(K): Coefficient (1.1~1.3)
-* * Actual selection * *: Refer directly to the power meter provided by the manufacturer to avoid calculation errors.
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**4. Special needs considerations**
-* * Noise control**
When a quiet environment is required, choose low-speed models or install mufflers/soundproof covers.
-Explosion proof requirements**
Explosion proof motors (Ex d Ⅱ BT4, etc.) should be used in flammable and explosive environments.
-Sealing method**
-Ordinary air: labyrinth seal.
-Special gases: mechanical seals or packing seals.
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**5. Brand and after-sales service**
-* * Famous brand reference * *:
-Changsheng brand
-Overseas: (), Taiko (Japan)
-Confirm the supplier's spare parts supply and maintenance response time.
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**6. Selection Example**
**Requirement * *: Convey clean air, flow rate 10m3/min, pressure 49kPa (0.5bar), at room temperature.
**Step * *:
1. Reserve a flow rate of 15 → select a flow rate of 11.5m3/min.
2. Reserve pressure of 10 → Select pressure of 54kPa.
3. Check the performance curve and select the model (such as Changsheng CSR-125).
4. Match the motor power (approximately 15kW, refer to the manufacturer's data for details).
5. No special environment, choose the standard model.
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**Common mistakes to avoid**
-Neglecting the characteristics of the medium, such as not selecting explosion-proof motors for transporting biogas.
-Confusion of pressure units: 1 bar ≈ 100 kPa, unified units are required.
-Excessive flow margin: leading to long-term inefficient operation of the fan and increased energy consumption.
It is recommended to confirm the parameters with the manufacturer's technical department before final selection, and provide system drawings or detailed operating conditions if necessary to optimize the plan.
