USA: A US company has been awarded patents for porous gas bearings that, it is said, could increase efficiencies in commercial and industrial cooling applications.
Said to be of particular value to the refrigeration industry, these new patents describe how the refrigerant itself can be used as the gas that provides the load carrying film in the bearing.
Gas bearings reduce the viscosity losses that are inherent in hydrodynamic oil bearings. According to patent holders New Way Air Bearings, these shear losses are almost completely removed by utilising gas bearings.
Additional efficiencies and cost savings are gained through the elimination of the oil pumps and filters and the need to cool the oil. The removal of the oil also prevents situations where oil leaks into the refrigerant which carries into the heat exchanger where the oil insulates the surfaces thereby reducing thermal transfer efficiency.
Many equipment manufacturers have turned to oil-free magnetic bearing technology to eliminate oil risk and improve efficiencies. Magnetic bearings also allow for hermetic operation that eliminates the need for high-speed seals that are additional reliability and cost factors.
However, most large chiller equipment continues to be built with conventional oil based bearings. New Way says that this is because magnetic bearings are complex and expensive to purchase and operate. Also, they are not serviceable by on-hand maintenance personnel, they require back up bearings, and ongoing software updates.
New Way says its porous gas bearings offer the efficient, hermetic, oil-less characteristics of magnetic bearings but at a similar price, form, fit and simplicity of traditional oil-based bearings.
Gas bearings can also be retrofitted into current oil-based bearing machines giving them an additional advantage over magnetic bearings that can only be designed into new machines.
“We have two of the largest OEMs in refrigeration equipment qualifying our gas bearing technology for future product release,” claimed New Way president Nick Hackett.