Multi stage centrifugal blowers are widely used in fields such as sewage treatment, pneumatic conveying, chemical engineering, metallurgy, etc. due to their high efficiency, large flow rate, and stable operation. But its selection needs to comprehensively consider the working conditions and equipment performance parameters, to avoid energy efficiency waste or equipment failure caused by improper selection. The following are the core points and steps for selecting multi-stage centrifugal blowers.
1、 Clear working condition requirements: from basic parameters to special requirements
The first step in selection is to accurately define the core requirements of the usage scenario, with a focus on the following parameters:
Flow rate (air volume): The volume of gas transported per unit time, usually measured in m ³/min or m ³/h. The maximum flow rate should be determined according to the process requirements, and a margin of 10% -20% should be reserved (such as future system expansion or operating condition fluctuations). For example, in the aeration process of sewage treatment, the required air volume needs to be calculated based on the tank volume and dissolved oxygen level.
Pressure (Boosting): The pressure value required to overcome pipeline resistance and equipment resistance during gas transportation, measured in kPa or mbar. The pressure range of multi-stage centrifugal blowers is usually 30-100kPa, and the total system resistance needs to be calculated based on the resistance curve of the pipeline network (including resistance of elbows, valves, filters, etc.).
Medium characteristics: The composition of the transported gas (such as air, biogas, and dusty gases), temperature (normal or high temperature), humidity, and corrosiveness (such as acidic gases in the chemical industry). If the medium contains dust, a filter should be provided; If it is a corrosive gas, corrosion-resistant materials (such as stainless steel impellers) should be selected.
Special requirements: Whether variable frequency regulation, explosion-proof design (such as in the gas industry), continuous operation cycle (24-hour/7-day or intermittent operation), etc. are required must be clarified in advance.
2、 Matching device performance: balancing power to efficiency
After clarifying the operating parameters, it is necessary to select suitable models based on the following equipment performance indicators:
Speed and Stage: A multi-stage centrifugal blower is pressurized step by step through a series of multi-stage impellers. The more stages, the stronger the boosting ability (usually 5-15kPa per stage). High speed (such as 2950r/min) can reduce equipment volume, but vibration control and bearing life need to be considered; Low speeds (such as 1450r/min) result in smoother operation and are suitable for noise sensitive scenarios.
Motor power: The power needs to be calculated based on flow rate, pressure, and efficiency. The formula is: power (kW)=flow rate (m ³/h) × pressure (kPa) ÷ (3600 × efficiency). Efficiency is a key indicator, and the insulation efficiency of high-quality models can reach 75% -85%. It is necessary to compare the technical parameter tables of different brands.
Noise and vibration: The main sources of noise in multi-stage centrifugal blowers are high-speed rotation of the impeller and airflow pulsation, with noise levels typically ranging from 80-100dB (A). If strict noise requirements are required (such as near residential areas), it is necessary to choose models equipped with soundproof enclosures, low-speed designs, or matched mufflers.
3、 Comprehensive consideration of brand and service
In addition to performance parameters, attention should also be paid to the following details:
Brand technology accumulation: Priority should be given to brands with independent research and development experience in multi-stage centrifugal blowers (such as TLT from Germany, Hitachi from Japan, Shaangu from China, etc.), whose products are more mature in impeller design, sealing technology, bearing selection, etc., which can ensure long-term stable operation.
After sales service network: The blower needs regular maintenance (such as changing lubricating oil, checking impeller wear), and it is necessary to confirm whether the supplier provides localized services (such as response within 48 hours, spare parts supply cycle).
Energy efficiency and certification: Priority should be given to products that meet the national first level energy efficiency standards (such as GB 19761-2020), and whether they have international certifications such as CE and ISO should be checked to ensure long-term economic and reliability.
Conclusion
The selection of multi-stage centrifugal blowers should be based on operational requirements, comprehensively matching parameters such as flow rate, pressure, and medium characteristics, while also considering equipment efficiency, noise, and after-sales service. It is recommended to communicate with professional engineers during the initial selection stage, and use CFD simulation or performance curve verification to avoid the situation of "big horse pulling small car" or "small horse pulling big car", ultimately achieving the optimal balance of energy efficiency, cost, and reliability.
