Overview

Permanent Magnet Motor on Magnetic Bearings driven by a Variable Speed Drive for a Magnetic Rotary Atomizer.

Customer Specifications

Dedert, a U.S. based dryer and evaporator systems manufacturer, approached Calnetix to design an atomizer system to eliminate costly gear drives, belts, conventional bearings and lubrication systems.

Solution

Working with Dedert, Calnetix developed a Magnaforce™ permanent magnet motor system on Powerflux™ magnetic bearings (250 kW and 16,000 RPM) for a magnetic rotary atomizer that offers low maintenance and high reliability compared with conventional rotary technology. Dedert Atomizers are also provided with a Calnetix Vericycle™ variable speed drive and an Insight™ magnetic bearing controller.

Challenges

Calnetix engineers experienced several challenges imposed on the bearing system by the atomizing process. There were large, highly-dynamic rotor imbalances and quasi-periodic external radial impulses on the magnetic bearings. A novel impulse detection and recovery system was introduced to alleviate the effects of external impulses, and additionally, several design changes were systematically implemented to mitigate the effects of the unusual rotor imbalances. These changes were successful in improving the operability and reliability of the machine.

Also, the nature of the atomizer application necessitates the location of the drive components at a considerable distance from one another and in completely different locations. The Calnetix Vericycle™ VSD and the Insight™ magnetic bearing controller had to be integrated with the supervisory control and data acquisition (SCADA) system of the end-user for proper and safe operation of the atomizer system and the entire dryer tower.

Results

The technologically advanced MSM-250 Magnetic Spray Machine provided precision engineering, exceptional reliability, and unparalleled performance. The non-contact magnetic bearings allowed the 325mm diameter disc to rotate up to speeds of 16,000 rpm, resulting in disc peripheral speeds of 275 M/sec. This translates to extremely efficient delivery of high power with very low maintenance.  And, with no lubrication needed, the MSM-250 atomizer completely eliminated the risk of oil contamination to sensitive products. These features optimized chamber air and particle flow characteristics, to keep the roof and walls free from product build-up, which is especially effective in food and pharmaceutical applications. The atomizers readily adapted to the existing installations to increase spray dryer capacity and greatly reduce maintenance costs.