As many as 50% of rotating equipment failures are attributed to misalignment. David Proud, general manager of Reich Drive Systems UK, discusses the importance of adhering to specifications.
For a drive coupling to be fully effective, it is essential that not only is the correct type of coupling specified for the application, but also that the coupling is also correctly installed and aligned.
Although certain coupling types are designed to accommodate some shaft misalignment or displacement in service, there are limitations. If a coupling is not properly aligned, or has levels of misalignment outside the manufacturer’s specifications, this will result in premature failure of the coupling and potentially other drivetrain components.
“Coupling alignment” is best defined as making sure, as far as possible, that there is a finely toleranced and common rotational centreline between the shafts that are to be coupled together. This will allow them to transmit power efficiently and operate reliably over extended periods.
There are a number of different types of misalignment that can contribute to problems in a drivetrain. They include angular, axial, and radial misalignment, or in extreme cases, a combination of one or more alignment issues. Reasons for misalignment can range from gradual movement of machinery over time or the fact that the drivetrain was not properly aligned at the time of installation.
Keep to specifications
As for any other piece of engineering machinery, drive couplings should be installed and maintained in line with the original manufacturer’s recommendations. Spending time to make sure a coupling has been correctly fitted and aligned will pay dividends in the form of long and reliable service.
There are a number of different methods of aligning a coupling, ranging from basic tools such as straight edges and feeler gauges, through to sophisticated laser alignment systems. The benefits of laser technology include the fact that many laser shaft alignment systems use software that can calculate accurate values for any adjustments that need to be made to achieve perfect alignment.
The important factor is making sure alignment is within specification, regardless of the method used. Misalignment outside the coupling’s specification will cause it to wear at an accelerated rate. In addition there is the potential to affect other components, for example bearings, causing them to fail prematurely.
Flexible couplings
There may be instances where it is not possible to achieve perfect shaft alignment and in cases such as this, the choice may be to select a flexible coupling such as Reich’s Multi Mont Sella. These pluggable claw couplings have been field-proven over a number of decades. With the capability to compensate for axial, radial and angular misalignment, as well as absorb shocks and vibrations, these couplings can help to reduce the effects of alignment errors and vibration.
The Multi Mont product range covers a torque capacity from 40Nm to 1MNm, and is capable of operating at temperatures from -400°C to 1000°C. Innovations continue with the recent development of a high-speed version made from high-grade aluminium, which is capable of speeds up to 20,000rpm.
Additional benefits of this type of coupling are ease of assembly and alignment, maintenance-free design and the capability to change the flexible elements radially, without the need to decouple the drivetrain elements.
With a history spanning over 70 years, Reich-Kupplungen has built up unrivalled expertise in the design and manufacture of drive couplings for use in a wide range of industries and applications. The company has a reputation for its ability to provide customer-specific solutions through its D2C (Design to Customer) philosophy.
More information:
David Proud | +44(0) 161 714 4191 | www.reich-uk.com