Roots blower is a volumetric rotary blower that achieves forced gas delivery and pressurization by synchronously rotating a pair of precision machined "8" - shaped three bladed rotors in a closed cylinder. Its core principle is no internal compression - the gas is enclosed between the rotors and moves with the rotors to the exhaust port, relying on the high-pressure gas reflux on the exhaust side to achieve pressure increase. Therefore, it has significant advantages such as stable flow, adaptive pressure, oil-free lubrication, and compact structure. It is widely used in industrial scenarios such as sewage treatment aeration, pneumatic conveying, aquaculture oxygenation, electroplating mixing, and vacuum packaging.
1、 Core working principle and structural composition
Rotor structure: The mainstream adopts a three bladed involute rotor, which has lower pulsating noise, smoother operating characteristics, and an air flow efficiency improvement of more than 15% compared to a two bladed rotor.
Sealing mechanism: Maintain a micrometer level gap (0.05-0.2mm) between rotors and between rotors and casings, relying on precision machining to achieve non-contact sealing without the need for internal lubricating oil, ensuring clean and pollution-free output gas.
Five core components:
Chassis: carries and seals the entire pneumatic system;
Wall panel: fixing the rotor shaft end to achieve end face sealing;
Synchronous gear: Ensure precise synchronization and reverse rotation of the two rotors;
Oil tank: lubricating gears and bearings, not used for rotor lubrication;
Muffler: effectively reduces intake and exhaust pulsating noise, with a typical noise reduction amplitude of 15-25dB (A).
This device does not belong to centrifugal fans, and its air volume is proportional to the speed. The pressure is determined by the system back pressure and does not fluctuate significantly with changes in flow rate. It is a typical "forced gas delivery" device.
2、 Mainstream technical parameters and selection range
|Parameter Category | Typical Range | Description|
|Airflow | 0.49-348.25 m ³/min | Mini machines (<10m ³/min) are used for laboratory and small-scale aeration; Large scale machines (>100m ³/min) are used in municipal sewage treatment plants and cement plants|
|Pressure | 9.8-98 kPa (1-10m water column) | Conventional aeration pressure is 39.2-58.8kPa (4-6m water depth); High pressure type can reach 83.3kPa, used for pneumatic conveying and vacuum packaging|
|Power | 0.75kW-355kW | 2.2kW models are suitable for small systems with a capacity of 5-10m ³/h; Over 15kW is used for large-scale industrial projects|
|Speed | 1360-1460 r/min | Most of them are driven by fixed frequency motors, and variable frequency models can achieve energy-saving speed regulation, with an energy-saving rate of up to 20-30%|
|Noise level | 50-95 dB (A) | Low noise models ≤ 75dB (A), equipped with mufflers or soundproof covers can further reduce to below 70dB|
✅ Selection key: Select the model based on water depth (pressure rise=water depth x 9.8kPa/m), pipeline resistance, and medium cleanliness. It is recommended to use anti-corrosion nickel plated or stainless steel rotor type for aeration in sewage treatment to avoid corrosion failure.
3、 Major Chinese brands and distribution of production areas
Shandong Zhangqiu: Zhanggu (Shandong Zhangqiu Blower Co., Ltd.) - the main drafting unit of national standards, with the highest market share in China, covering a full range of products, and is a long-term supplier to central and state-owned enterprises.
Jinan, Shandong: Shandong Yinchi, Longzhitie, and Huadongfeng Machinery - Strong localized services, rich in high-voltage, intensive, and variable frequency models, suitable for local industrial and commercial users in Shandong to quickly purchase.
Yangzhou/Changzhou, Jiangsu: Jiayuan and Lizi Environmental Protection - specializing in energy-saving variable frequency and low-noise models, with a large export volume and high cost-effectiveness.
Quzhou, Zhejiang: Zhejiang Shouzheng - focusing on customization and precision manufacturing, certified by ISO9001, suitable for the chemical and pharmaceutical industries with high precision requirements.
Imported brands: NICO and NOTON Norton from the United States - providing high corrosion resistance and long-life models suitable for harsh working conditions, but at a price 2-3 times that of domestic products.
📍 Local advantages of Linyi: As an industrial hub in Shandong, Linyi is surrounded by a large number of Roots blower dealers and maintenance service providers. Local enterprises such as Shandong Yinchi and Longzhitie can provide 24-hour response, on-site installation and commissioning, and direct supply of spare parts services.
4、 Typical products on sale in the market and procurement references
The following are the actual models on sale on Baidu AiGou platform (June 2026 data):
Shandong Yishuanghui: Three leaf Roots blower for aeration, nickel plated anti-corrosion, priced at ¥ 8700, suitable for sewage treatment, with a speed of 1450r/min and an air volume coverage of 25-50m ³/h.
Shandong Yinchi: High pressure YCSR50-350, pressure 39.2-83.3kPa, power 5.5-90kW, supports frequency conversion, ¥ 5500, hot selling, suitable for pneumatic conveying and combustion furnaces.
Jinan Longzhi Iron: 15kW aeration fan, pressure rise of 58.8kPa, air volume of 500m ³/h, ¥ 6300, specially designed for organic fertilizer fermentation and water tank oxygenation.
Yangzhou Jiayuan: Variable frequency upright type, power 0.75-350W, noise ≤ 75dB, ¥ 19000, suitable for laboratory and precision control scenarios.
Shanghai Ruizhe Environmental Protection: Negative pressure vacuum fan, pressure -0.01MPa, air volume 190.8m ³/h, ¥ 6250, used for vacuum suction and vacuum packaging.
⚠️ Avoiding pitfalls tips:
Three leaf Roots blowers priced below ¥ 3000 are mostly annular high-pressure blowers (not genuine Roots), with different structures and principles, and cannot be replaced;
All non self owned roofs or rental projects must provide a CMA certified structural safety inspection report before installation;
Prioritize selecting complete sets of units with mufflers, fuel tanks, and protective covers to reduce installation costs in the later stages.
5、 Key points of installation and operation and maintenance
Installation environment: well ventilated, temperature ≤ 40 ℃, no rain, no corrosive gases; The foundation needs to be flat, it is recommended to install rubber vibration pads.
Daily maintenance:
Replace gear lubricating oil every 3-6 months (recommended VG68 or VG100 industrial gear oil);
Monthly inspection of synchronous gear mesh clearance and belt tension (for belt drive models);
The intake filter needs to be cleaned weekly to prevent dust blockage and overload.
Fault warning:
Decreased air volume → impeller wear or increased clearance;
Motor overload → exhaust pipe blockage or high back pressure;
Abnormal noise → synchronous gear wear or bearing damage.
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