Centrifugal blowers operate best as base load machines with a pressure and flow rate as dependant variables. Currently there are three different designs of modern centrifugal blowers in common use today –
- Multistage Centrifugal Blower - The multistage centrifugal blower is usually paired directly with an induction motor driveshaft which results in a slower operating speed. The design principals however are fairly simple – if you want more flow just increase the impeller diameter and if you want more pressure simply increase the number of impellers – or stages. As with all centrifugal machines the impeller configuration impacts greatly on the performance of a multistage centrifugal blower. A multistage centrifugal blower can have anything from two to eleven stages and any number of impeller geometries to create the desired pressure curve and design flow.
- Integrally Geared Turbo Blower - this is driven by an induction motor using a speed-increasing gearbox. While the motor rotates at only 1,800 or 3,600 revs per minute the blower impeller can rotate as fast as 30,000 revs per minute to produce the desired pressure and air flow.
- High Speed Turbo Blower - the AIR FOIL bearing high speed turbo blower was introduced into the wastewater market around 2007, unfortunately the technology was misapplied which lead to headaches for both consumers and manufacturers. The MAGNETIC HIGH SPEED TURBO BLOWER has been used in the waste water treatment industry longer than the airfoil design and over the years has proven to be extremely reliable due to the magnetic bearing controller that prevents a catastrophic failure. Both the magnetic high speed turbo blower and the Air foil machines use a high speed permanent magnet motor which is controlled by frequency drives that allow the impellers to turn up to 60,000 revs per minute to create the desired pressure and airflow.
Which one should you choose?
Of the three centrifugal technologies listed above the multistage centrifugal blower offers the most versatility when it comes to wastewater treatment. This is due to its ability to convey digester gas as well as air. The multistage centrifugal blower also offers the widest flow range thanks to the numerous configurations it has available to use. The integrally geared turbo blowers offer the biggest flow rates and because if this they aren’t suited to small plants. The high speed turbo blowers have the greatest potential for use in industrial wastewater applications due to its integrated control system, small footprint and amazing efficiency.