The hybrid retainer for minimizing friction and extending service life.

Sensitive special devices for measuring the flow rate of liquids and gases or anemometers for measuring wind speeds require ball bearings with very little friction.

GRW developed a new ball bearing retainer type called XTRAflow especially for these tough applications. The retainer meets all the stringent bearing technology requirements for anemometers in terms of start-up, dynamic friction torque and stability of the low friction torque over time.

XTRAflow is a special ball bearing retainer, manufactured using a procedure developed and patented by GRW. The hybrid material used is a combination of stainless steel, which gives the retainer the strength it needs, and a fluoropolymer with modified friction and wear properties.

A low-friction ball bearing used to measure flow rate and wind has to be able to measure minuscule flow rates and very light winds. Thanks to the constantly low dynamic friction torque achieved with the XTRAflow, the retainer does not perform any micro-movements when measuring or counting. Micro-movements during measurement result in random peaks in measured values, which distort the result and do not therefore allow the flow rate to be determined with accuracy. Once the media flow has been stopped or the wind has subsided, it must also be possible to reproduce and display these run-out dynamics.

The special GRW ball bearing with our new XTRAflow retainer displays its outstanding slide and friction properties even if insufficiently lubricated. This is the result of a transfer coating, which is applied from the retainer surface over the balls to the tracks of the inner and outer races and prevents contact between solids once the hydrodynamic lubricating film is lost.

Even if oil or grease lubrication is not applied during maintenance, reliable operation is still possible when using this special GRW ball bearing retainer.