A high-performance coupling high-speed shear spacer cartridge shown being checked for runout during installation and alignment on the gearbox end of a drivetrain.
The Kop-Flex high-speed shear spacer coupling uses a patented double-tube design, precision machining and bearings, and special metal treatments to help provide predictable shear during torque overloads on turbo drive trains, allowing safe coast down of systems turning at up to 20,000 RPM. Developed to protect gas turbine powered generator drives during electrical faults, the shear spacer is also ideal for drives on compressors, pumps, fans and trains subject to shock torques.
"The patented shear cartridge uses special bearings between two tubes to maintain concentricity and overall centering after high-speed separation," said a company spokesperson. "The double bearing design, precision grooving, shot peening and a corrosion resistant coating combine to increase fatigue resistance and promote reliable operation over the life of the coupling. The high-speed shear spacers are available in all catalog coupling sizes capable of handling speeds up to 20,000 RPM and millions of inch-pounds (or Newton-meters) of torque."
The high-speed shear spacer is intended to be an improvement over standard shear spacers and shear pins, which can create issues when used above 3,600 RPM due to balancing issues and fretting potential when using pins, according to the company. "Standard shear spacers are not engineered to survive the unbalanced forces that develop when turbo drive trains hit a torque overload at high speeds (3,600-20,000 RPM)," said Joe Corcoran, Manager of Global Services and Training for Emerson's Kop-Flex coupling business. "Coast down from high speed can be unpredictable with a standard shear spacer, and more damage can result.
"This design takes the standard shear spacer concept to a whole new level of technology. We start with a comprehensive understanding of the material properties of each unique unit, and use metal treatments, testing, precision machining and special bearings to create a custom shear spacer for each application."
During manufacture, the spacer's parts are heat treated with a sample from the same metal batch. Samples are tested to determine exact shear strength, and test data is used to design and machine a precision shear groove on the spacer. Polishing the surface minimizes stress concentrations, and shot peening compresses the surface layer to minimize chances of crack growth. A special corrosion resistant coating is also available to further stabilize the surface.
"Our tests show we are able to predict the static shearing force within 1.5% on a finished unit, and we have successfully run these cartridges at high speeds after separation to validate they can provide ample time for equipment coast down," said Corcoran.
For more information contact:
Emerson Industrial Automation
Power Transmission Solutions
7120 New Buffington Road
Florence, KY 41042-2841
859-342-7900
customerservice.ptsolutions@emerson.com
www.powertransmissionsolutions.com