What determines the quality of the turbo blower

Turbo blower

Compact power in the aeration tank.

The turbo blowers from AERZEN. Over many decades, we have taken these units to the top technologically. And in the process developed expertise that sets standards worldwide. It is reflected in high energy efficiency, low life cycle costs and specially developed core components. In short, it lives in all the details of the AERZEN flow machines.

Magnetic vs. air storage - AERZEN air storage: more than just one step ahead!


The structure and operating principle of a turbo blower from AERZEN are simple and effective at the same time. Because the air supply in modern sewage treatment plants is clearly designed for maximum availability, high energy efficiency and long maintenance cycles, AERZEN does not use oil or other lubricants for the demanding storage inside the turbo blower - it simply uses air.

AERZEN Turbo Generation 5

AERZEN Turbo Generation 5plus

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AERZEN turbo blowers for wastewater applications

Turbo blowers or turbo compressors are often used in wastewater treatment. Reliability, energy efficiency and reduced maintenance costs are extremely important in this area. In sewage treatment plants in particular, turbo machines have to do their job without major interruptions due to maintenance and repairs - they convey air into the so-called aeration basins.

The air is used to supply the microorganisms in the pool with oxygen. The more efficiently this is achieved, the better. The tasks are enormous: In order to bring the necessary oxygen into an aeration tank, the flow machines have to function smoothly in a difficult environment for long periods of time. Frictionless is actually to be understood in the literal sense, because at the high speeds that are generated inside a turbo blower, conventional ball bearings or other mechanical bearing solutions, which always cause a certain amount of friction, are not practical.

This is why bearings are required for turbo machines in wastewater applications that function without mechanical friction and ensure contactless operation of the turbo impeller during the compression process.

Solutions for the smooth storage of turbo compressors - magnetic or air storage

There are basically two possible solutions for the implementation of frictionless and contact-free bearings for turbo compressors: magnetic bearings and air bearings. Thanks to the contact-free storage, there is no need for maintenance using lubricants such as oil. This is why modern, speed-controlled turbos are also called “oil-free” high-frequency turbo compressors. For a long time, magnetic bearings were considered the most practical solution.

With this type of storage, the generation of corresponding magnetic fields inside the fan completely avoids contact between the rapidly rotating shafts and other components. This solution is highly complex and the implementation is technically very complex, because in order to guarantee smooth functioning in the literal sense of the word, the system must constantly query the exact position of the shaft. Only then can the complex electronics adjust the magnetic fields as precisely as is necessary for trouble-free continuous operation.

The use of sensitive sensors and the overall very complex control electronics also have disadvantages. On the one hand, the ambient conditions in sewage treatment plants are often not ideal for sensitive components. On the other hand, the complex control mechanism requires regular maintenance work. In addition, there is a high sensitivity to operational and process-related pressure fluctuations and peaks, as well as technology-related properties such as compressor pumping.

Because both of these create dynamic forces that act on the rotor of the machine. Magnetic bearings have narrow limits due to their complex control loop and are quickly switched off for self-protection in such situations. This leads to frequent failure of the turbo machinery on many systems.

One of the most significant disadvantages is the very limited service options, because in the event of a repair or a necessary replacement of the bearing, this cannot be done at the installation site, but only at the manufacturer. In addition to the considerable logistical effort, this means a critical and long downtime of the machine of approx. 3 months. With regard to the energy balance, the magnetic bearing is also not optimal, because electricity is required permanently to generate the magnetic field, which drives up the operating costs of the turbo compressor. In addition, a backup battery must be kept ready as a stopgap in the event of an interruption in the power supply.

This so-called UPS (uninterruptible power supply) ensures that the high-frequency rotating rotor does not immediately come into contact with the mechanical emergency bearing if the power supply fails. The load on this emergency storage would be so high at full speed that damage would be the likely consequence. The UPS can only be switched off after the speed has dropped to a non-critical level. Since the built-in batteries must always be fully charged and have stable performance, a UPS also requires its own maintenance effort.

The battery storage systems must be checked regularly using a special maintenance plan and damaged or already weak battery cells must be replaced. Overall, the solution using magnetic bearings is therefore cost-intensive, technically complicated and energetically inefficient. That is why AERZEN relies on a different system.

AERZEN relies on air for contact-free storage

Air bearings are used as a standard solution in the AT and TB series turbo blowers. The principle of contact-free air storage has immense advantages over mechanical and magnetic solutions. Functional principle and operating behavior within the turbo are based on very simple physical principles. The motor shaft connected to the impeller must be mounted absolutely reliably, a task that cannot be performed with standard roller bearings in the industry due to the high speeds.

The air bearing for turbo blowers developed by AERZEN offers decisive advantages in comparison, because it is simple and energy-efficient. Compressed air is used as an air cushion in both radial bearings of the drive shaft and in the axial bearing.

This air does not come from an external pressure generator, but is generated by the turbo blower itself, as with conventional compressors. As soon as the fan is switched on, the shaft generates an eccentric circular movement. This increases the pressure in the minimal gap to the bearing wall, which in turn pushes the shaft in the opposite direction. The high speeds ensure that the shaft is automatically centered in the bearing and increase the operating pressure in the air gap to over 30 bar. The high pressures generated ultimately cause the shaft centered in the bearing to float freely. This type of storage is a further development from space travel.

In contrast to magnetic bearings, no additional energy is required to generate the air cushion, as this is formed automatically during normal operation. In addition, the operating costs decrease because the storage is completely maintenance-free. The immunity to interference, due to the simple and robust structure of the system, is a distinctive feature of the technology. Even difficult operating conditions, such as load and pressure fluctuations, are compensated for by simply using physical properties.

However, should a repair be necessary, all relevant components can be exchanged within a few hours and, above all, directly at the installation site. Contact between the friction partners in the bearing occurs only when the turbo compressor is started up or shut down until the air cushion is built up. In order to prevent premature wear and tear, AERZEN relies on an innovative air film storage system. The bearings and shaft are provided with a 2-component coating made of graphite and Teflon. This has a high temperature and friction resistance. This double "non-stick coating" significantly reduces mechanical loads and wear when starting up the machine.

Ease of maintenance, energy efficiency and low life cycle costs

With air storage, the AERZEN turbo generations set new standards in terms of ease of maintenance, maintenance intervals and energy efficiency. The modern turbo compressors are extremely resilient and can easily be used in 24-hour operation in sewage treatment plants and other areas of wastewater technology. In contrast to flow machines from other manufacturers, the blowers of the TB and AT series are also suitable for SBR systems (sequencing batch reactor) due to their control range and the possibility of idling operation. Idle operation is considered to be significantly more energy-saving than constantly switching the entire system on and off.

Of course, all relevant parameters of the turbo blower can be queried in real time. A real highlight is the real air volume measurement, which most other manufacturers derive indirectly from power consumption. The AERZEN systems use the so-called Venturi principle, which realizes the air mass sucked in by measuring the differential pressure.

With this technology, you can see at any time what amounts of air are being conveyed. The operating behavior of sewage treatment plants can be significantly optimized on the basis of the values ​​determined. The efficient development of power has a positive effect on energy consumption in the long term. The purchase price of the compressor amortized relatively quickly due to the energy costs saved and therefore hardly plays a long-term role. In sewage treatment plants, more than half of the energy required is used to supply the activated sludge tank with oxygen.

It can therefore make sense to switch to a modern system, for example a combination of turbo blower, rotary piston blower and rotary piston compressor, a so-called "blower network". Low life cycle costs and flexible operation make the AERZEN systems particularly attractive. The scope and size of the system determine the general conditions of the respective system. AERZEN offers customer-specific products and solutions for this - this is an important factor, especially when retrofitting older systems.

Regardless of which AERZEN product you choose: All components are manufactured to the highest quality and optimized for durability and efficient use.