Sometimes to make the world a better, greener place you have to re-think an old rule. Today, thanks to a number of engineering innovations, the squeaky wheel (or in this case, the shaft bearing) is not getting the grease -- new "frictionless" technologies are making industrial equipment such as compressors, turbines, and motors more affordable, efficient,and environmentally friendly.
It's one example in a shifting paradigm. According to a third quarter report from the Cleantech Group and Deloitte, the global "cleantech" sector attracted $1.59 billion in venture capital investment across 134 companies-up 10% from the previous quarter this year. In fact, cleantech is projected to make up more than one quarter of venture capital funding in 2009, making it the largest single sector for that form of financing.
It needn't be massive projects that change the world, though. In the case of magnetic bearings -- the change may appear less visible but the impact is quite substantial.
For decades, industrial machinery required significant amounts of lubricant to keep bearings functioning, and the promising concept of magnetic bearings was held in check by the realities of existing technology. Where oil films are conventionally used to prevent friction and wear between sliding surfaces, magnetic bearings maintain a small gap between the surfaces using magnetic forces, eliminating the need for lubricants. Eliminating lubricants also greatly reduces viscous friction, which makes the machine more energy efficient.
Historically, the larger size and complexity of magnetic bearings has made them difficult to integrate into a rotating machine, limiting the range of applications. The cost of magnetic bearings system has also been a limitation. But recently, a new generation of magnetic bearings has emerged using design innovations that benefit from technology advances in the fields of digital processing and power electronics. The magnetic bearings allows the elimination of "old technology parts" such as oil reservoirs, pipes, heat exchangers, filters, and gears, and replaces them with "new technology parts" such as electromagnets, digital processors, sensors and communication networks.
Some of the technology is mind-boggling: a digital processor uses sensor information to determine the actual spacing between rotating and stationary components, and then calculates what new distribution of magnetic forces are needed to maintain the desired spacing. The digital processor then instructs the power amplifiers as to the proper voltages to apply to the electromagnets to achieve this spacing. This cycle of sensing and correction occurs at about 15,000 times per second, and ensures that the magnetic bearings can almost instantaneously compensate for any disturbances. The optimal spacing between the stationary and moving surfaces is typically about 1/100th of an inch, or about three times the diameter of a human hair!
The payoff came not only in the form of a great product, but in recognition, as well. In July 2009, the prestigious R&D magazine named Synchrony's Fusion magnetic bearing as one of the 100 most technologically significant products of the past year.
Today, magnetic bearings improve reliability, reduce friction, minimize vibration and offer advanced health monitoring and diagnostics -- all without the potential environmental disadvantages of lubricants.
View article on one page