Manufacturing advancements underpin enhanced sizing flexibility for Auma’s part-turn GS gearboxes. Three duty classes, (1, 2 and 3), have been introduced to support all anticipated operations across predicted valve lifetimes.
The new classifications, paired with the introduction of additional flange sizes, enable the company’s GS gearboxes to be mounted on larger valve flanges.
Auma GS gearboxes play a key role automating large scale butterfly and ball valves: the company’s established range caters for torques between 500 to 675,500 Newton metres. Comprehensive product revisions undertaken by Auma encompassing corrosion protection, surface treatment of metals, enhancement of connection technologies and selection of optimal lubricants have improved the mechanical properties of the gearboxes and given Auma a platform to reassess permissible torques.
With no binding standard for valve gearboxes, Auma continues to adhere to EN 15714-2, which defines high lifetime requirements for actuators. EN 15714-2 specifies a sophisticated load profile for type tests and lifetimes up to 10,000 operation cycles, depending on the device’s size. Auma’s rigorous test procedures confirm that its devices exceed these standard requirements.
The lifetime specifications of the standard are the basis of Auma’s newly introduced duty class 1 gearbox. For duty class 2, assuming infrequent operation, 1,000 duty cycles is assumed: this increases the permissible gearbox torque by 25 percent. In these instances, smaller and more cost-efficient gearbox sizes can be selected to suit the customers’ applications. Duty class 3 is adopted for manually operated gearboxes enabling higher torque levels due to extremely infrequent operations.