Vulkan’s largest clutches serve dredger pumps

Integrated drive systems for suction dredgers and offshore vessels are a speciality of Herne, Germany-based Vulkan Couplings, whose recent projects included components for one of the largest trailing suction hopper dredgers in the world.

Owned by the Malaysian company Inai Kiara, the 32,000m³ capacity Inai Kenanga can dredge at depths down to 35m deploying two suction pipes in standard configuration; using extension pipes, the dredging capability can be deepened to 120m. Vulkan supplied its largest-ever clutches for the gearboxes of the installation’s powerful sand pumps.

A total of six of the designer’s MESLU clutches were delivered in co-operation with Chinese subsidiary Wuxi Vulkan to serve two GJZ 2250-type Siemens/Flender triple-gear sand pump gearboxes. A size 540 clutch facilitates shifting to first gear while two smaller size 330 clutches handle shifts to second and third gears.

In addition to the clutches, Vulkan was commissioned to supply all the highly flexible couplings for both main and suction pump operation, with a RATO S 582Z-type coupling for the drive operation. Highly flexible RATO R 473Z-type couplings provide the necessary torsional vibration damping and misalignment compensation in the pump system on the front side.

A benefit of this overall solution, Vulkan reported, is that the complete drive system can be optimally tuned with respect to torsional vibration thanks to single-sourcing of the components. Maximum system availability and minimal operating costs are thereby fostered. Vulkan MESLU clutches are offered in a range of sizes to cover power transmission requirements from 8 kNm to 250 kNm.

An increasing commitment to the offshore oil and gas industry in recent years has seen growing business for Vulkan couplings in FPSO vessel, semi-sub, drill ship, jack-up rig and shuttle tanker drive installations. Anchor handling vessels, heavy lift tonnage, tugs, pipelayers, diving/ROV and oil spill recovery vessels are also typically supplied. Such applications, said Vulkan, call for operating times of up to 7,000 hours annually, with high demands on performance and manoeuvrability.

Drive systems with low space requirements are favoured to release more room for specialised operations by offshore vessels that are increasingly specified with diesel-electric power and propulsion systems. Vulkan’s highly flexible RATO series couplings are said to be particularly valuable for these applications in combination with elastic mounts, together reducing vibrations and damping propeller excitation.

Vulkardan G couplings are designed especially for generator and Z-drive thruster installations, matching both the SAE engine range with size 54 to 62 models and non-SAE engines with the size 84 model. A torque band from 8 kNm to 63 kNm is covered by the couplings, which were developed for rigidly-mounted systems where it is possible to dismantle the elastomer without shifting the connected units.

Excellent values for power loss in the coupling are reported thanks to the element design. A new type of elastomer with proper torsional rigidity, CTdyn, enables systems to be tuned optimally with respect to torsional vibration. Harmful resonant frequencies are thereby eliminated from the operating speed range and impact on engine control prevented.

Vulkan says it can provide ‘holistic’ solutions for drive systems, matching the wide range of couplings with elastic mounts for diverse applications for protection against harmful vibrations as well as securing reliability and maximising availability. MP