Dry Flexible Accessory Coupling
« Back to Glossary
The coupling is generally supplied with the same shaft end mounting arrangement as previously used for the gear type coupling. On gas turbine applications the shaft end arrangement is usually flanged, and in a few cases is taper fit or interference fit with keys.
The dry flexible element coupling is selected to minimize the need for modification of the existing equipment and is usually directly interchangeable, except for modifications to the existing coupling guards and oil spray nozzles. In most cases, the replacement coupling can be selected to have similar stiffness and weight as the original gear coupling in order to avoid changes in the rotor dynamic behaviour of the machine. Dry couplings fall mainly into two categories:
The first is Diaphragm Couplings, were torque is transmitted by the coupling hub bolted to one/two diaphragms welded to the spacer. The main advantage of this type of coupling is the simple configuration and therefore the limited problems in balancing and the absence of fretting problems, i.e., rubbing and corrosion caused by friction between the flexible torque transmitting elements.
The second is Multiple Membrane Couplings, were torque is transmitted by the coupling hub bolted to some of the flexible elements which are in turn, bolted to a spacer. The main advantage of membrane couplings is their light weight and thus reduced overhung moment.
Contact GMB Associates