What is an air suspension fan?

 Can it really save energy and reduce consumption in sewage treatment? As we all know, if the sewage treatment industry wants to save energy and protect the environment, it is generally carried out from two levels, one is the choice of production process, and the other is the choice of machinery and equipment. The first one is nothing to say, most of the sewage plants now in use in our country use activated sludge aerobic process. On the second point, I want to talk about the fan. In the sewage treatment process, the blower used to provide biological tank aeration, accounting for 50% to 70% of the unit power consumption, known as the electric tiger in the sewage treatment system, accounting for more than 70% of the total cost of sewage treatment. 

Therefore, it is of great significance to choose the blower with better performance for the energy saving and operation management of the sewage plant. The previous life of the aeration fan - the traditional Roots fan and the multi-stage centrifugal fan, both technologies are from the last century, the common shortcomings are: large power consumption, complex structure, need lubrication, high failure rate, large volume, high noise, high maintenance costs. With the development of The Times and the progress of science and technology, it has been iterated constantly - air suspension centrifugal fans and magnetic suspension centrifugal fans have become representatives of new fans. Today, I will take you to understand the air suspension blower in detail. We have five sections that you can read on demand. ·

 What is Air Suspension Blower Composition and principle of air suspension fan · Technical advantages of air suspension fan · Application case in sewage treatment plant · Video explanation of air suspension fan 

 01. What is an air suspension blower? The air suspension blower is a kind of blower in which the air rotates at high speed in the blower rotor, and the dynamic pressure effect is generated between the rotor and the foil bearing surface, forming a high pressure air film and floating the rotor. The main function of sewage treatment is to aerate the water to increase the oxygen content in the water, so as to remove iron, remove manganese or promote aerobic microorganisms to degrade organic matter, and achieve the purpose of removing oxidizable precipitated substances. In addition, aeration can make water and air fully contact to exchange gaseous substances to remove volatile substances in water, such as removing the smell of water or harmful gases such as carbon dioxide and hydrogen sulfide; It can also play the role of aerating the bottom sediment by air intake through the bottom air duct and discharging through the waste water pump. 

 02. Composition and principle of air suspension fan Air suspension fan mainly includes impeller, air suspension bearing, frequency converter, high-speed permanent magnet motor and its structure control system. The motor spindle is coaxial with the fan impeller, and the high-speed rotor system is directly supported by the air suspension bearing. Its main core technology is air suspension bearing technology, high speed permanent magnet synchronous motor and its control technology. The air suspension bearing takes air as the working medium, elastic flat foil as the supporting surface, and elastic wave foil as the supporting member. Initially, the impeller rotor is in contact with the bearing, but when the rotor enters a high-speed rotation state, due to the viscosity of the air and the action of the wedge, there will be a dynamic pressure effect between the planes. On the surface of foil and rotor, elastic deformation of flat foil and corrugated foil occurs, the flat foil is pushed away, and then the rotor is suspended in a state of uneven circular air pressure makes the foil bearing have the ability to bear the load. Or more simply, during the rotor's high-speed rotation, a high-pressure gas film is formed between the rotor and the foil, thereby lifting the rotor. 03. Technical advantages of air suspension blower

 1) Energy saving and high efficiency using suspension bearing, no contact loss and mechanical loss, to achieve high speed infinite variable speed adjustment, making the fan operating efficiency up to about 95%. 

 2) Low noise, small size, easy installation All components are integrated on the common base, no special fixed foundation is required, small size, light weight, easy installation and operation, low noise and no vibration during operation, noise level < 80dB. 

 3) System integration High blower itself has integrated local control and frequency conversion system in one, there is no need to set up a separate frequency conversion cabinet and operating cabinet. Through the control panel of the fan itself, various functions can be set and parameters such as fluid temperature, motor revolution, air pressure, air volume, power consumption can be queried. 

 4) Simple use, easy maintenance, low cost, long life blower motor and impeller directly connected, gearless growth device, no mechanical contact, no lubricating oil system, no wear and energy loss, low maintenance costs, power transmission efficiency of more than 95%. The impeller is made of high strength aviation aluminum and Ti material, with excellent wear resistance and deformation resistance, and the service life is more than 30 years. The frequency converter is used to adjust the air volume, which is energy-saving than the throttle valve, and the air volume adjustment range is wide, generally 50% to 100%. 5) High cooling efficiency The cooling system adopts the combination of air cooling and water cooling, which can effectively protect the motor and realize the start and stop of the fan at any time. 6) The remote control adopts PLC+GPRS. Not only can it be controlled by the central control room, but also remote maintenance and debugging can be implemented if the fan fails. 

 04. Application cases in sewage treatment plants After the upgrading and expansion project of A sewage treatment plant, due to the adoption of A/A/O-MBR process with high sludge concentration, the original Roots fan could not meet the aeration requirements, so the Roots fan was transformed into an air suspension blower. The sewage plant has 3 Roots blowers, 2 used and 1 standby, the service life has been for many years, and the performance has gradually decreased. 

The biological tank aeration needs to open 3 fans, and the blower motor temperature is too high during normal operation, which can reach about 100℃. The long-term high temperature causes the lubricating grease of the motor bearings to deteriorate and lose the lubricating effect, resulting in a high failure rate of the fan motor and frequent repair. Can not meet the normal process requirements. In addition, the operation noise of the Roots blower in the blower room is too large, about 110dB. In order to meet the needs of normal production, ensure the discharge of effluent water quality up to the standard, and improve the working environment of the blower room, it is decided to use air suspension blower to replace the old fan. The air volume is adjusted daily according to the actual water quantity and water quality according to the configuration of 1 use and 1 standby. Since the air suspension blower comes with a soundproof cover and has no friction during normal operation, the noise in the machine room is greatly reduced. It is less than 70dB. After the renovation of the project, the operation of the original two to three Roots fans must be opened to only one air suspension blower to meet the aeration requirements; The noise in the blower room is greatly reduced; Under the condition of stable treatment capacity and water quality, the effluent water quality basically does not change, and the air suspension fan saves about 20% energy than the Roots fan. A total of 1.59 million yuan has been invested in this project. Under the current treatment capacity and water quality, the air suspension fan can save 402773kwh of electricity per year by saving 0.061kwh/m3 compared with Roots fan. According to the unit price of electricity is about 1.1 yuan /kw·h, it can save electricity for the sewage plant about 400,000 yuan/year, and it is expected that the investment cost can be recovered within 4 years. I

f you add the original 42,000 yuan per year for Roots blower overhaul, it is expected that the investment cost can be recovered within 3 years. 05. Conclusion At present, the secondary biological treatment stage of sewage treatment is mostly the aeration process at the bottom of the blower, so the choice of the blower will directly affect the investment and long-term benefits. As one of the commonly used equipment for sewage treatment in the future, air suspension blower has the advantages of high efficiency, high performance, low noise, low energy consumption, less maintenance work, etc., and has great application prospects in the sewage treatment industry!