The port consists of several berths and yards where 15 million tons of ore per year can be unloaded from huge ocean-going vessels. Various bulk handling machinery installed throughout the port by three different OEMs has one thing in common: in all of these super-size loaders, unloaders, and stacker-reclaimers, a total of over 170 geared motors supplied by German manufacturer NORD DRIVESYSTEMS ensure everything stays reliably in motion.
Now often billed as an island paradise, the Zhoushan Archipelago comprises more than 1,300 scenic isles and islets off the Chinese eastern seaboard.
However, Zhoushan’s emergence as a popular tourist destination is a relatively new development. By contrast, its other role as a center of trade is steeped in an old tradition. Zhoushan’s major islands lie just a few miles off the coast, close to Ningbo in Zhejiang province and about 150 miles south of Shanghai and the Yangtze estuary. Even centuries ago, their proximity to these bustling cities and the Yangtze, one of China’s premier waterways, has made the Zhoushan ports the region’s chief entrepôts for all sorts of goods. In modern times, these have come to include industrial commodities such as steel, mostly destined for Wuhan Iron and Steel Group (WISCO), China’s oldest steel giant headquartered about 400 miles inland up the Yangtze. Though WISCO operates a number of mines in China, high-quality ore is domestically in short supply. Hence, the company must source most of its iron from abroad. Water transport on the Yangtze is the obvious, highly efficient, and economical choice, but ore imports for the industrial group usually arrive in the East China Sea in very large ocean-going vessels. Inevitably, these must call at a coastal port, where cargo can be offloaded and transferred onto smaller ships – even on the lower reaches of the Yangtze, large freighters would be stopped cold at the river bridge in Nanjing. 10,000 dwt ships, on the other hand, can pass under it and make their way onwards to Wuhan.
New port with super-size machinery
Demand for WISCO’s products has grown steeply over the course of the last decade in particular. As raw materials are needed in Wuhan in ever-growing quantities, establishing additional unloading and loading bases along the coast – preferably under WISCO’s own direction – had become a pressing issue some time ago. Partnering up with two co-financiers, WISCO eventually came to hold a stake in a new port construction project in the island town of Wugang, in the south of the Zhoushan Archipelago. All facilities at Wugang Port were built in 2010 and 2011. The German manufacturer of full-scale drive solutions, NORD DRIVESYSTEMS, supplied more than 170 heavy duty geared motors. As inspections, test runs and approvals for full-scale operation have concluded in mid-2012, Wugang now serves as WISCO’s main transshipment terminal with a cargo throughput of up to 30 million tons of ore per year. The port includes an unloading berth boasting a water depth of 27 m, where huge ships carrying up to 300,000 dwt can arrive. Three loading berths are 15 m deep and can accommodate smaller ships – one will fit a 50,000 dwt class vessel, two are cut out for 10,000 dwt ships. Designed to handle up to 5,000 tons of ore per hour, the ship loaders, ship unloaders, and bucket-wheel stackers installed along the berths and yards in Wugang Port are all the biggest equipment of their kind for civil use in China.
Reliable drive solutions are essential
Given Wugang Port’s location and limited accessibility from the mainland and even the larger islands of the Archipelago, WISCO’s key requirement for all heavy machinery was extremely high reliability and low maintenance characteristics. It takes at least one hour for a maintenance crew coming from the coast or Zhoushan Zhujiajian Airport to get to Wugang by ship, plus possible delays in bad weather, which might also rule out helicopters as an alternative. In any case, serious problems with machinery would very likely incur staggering costs for repairs and, of course, disturbances of unloading and loading processes due to dysfunctional equipment. Therefore, highly reliable drive solutions are required to ensure that large gantry cranes, conveyors and the like keep moving.
NORD DRIVESYSTEMS was commissioned to supply heavy duty geared motors. Headquartered near Germany’s foremost harbor city of Hamburg, this company was anything but a stranger to the maritime world: NORD has a long track record of supplying mechanical and electronic drive technology for gantry cranes and other port machinery – albeit in other parts of the world. Though NORD now has a considerable presence in China that includes several production and assembly plants and a number of regional offices, the German company only set foot in the country a couple of years ago.
Still, the superior quality and durability of the drive products as well as the pre- and after-sales services proffered by the drive specialist prompted WISCO to have the bulk handling machinery at Wugang Port equipped with geared motors supplied by the Chinese branches of the German company. A very experienced manufacturer of top-quality large gearboxes, the company ensures long service life, minimum maintenance requirements, and high load tolerance for the complete geared motor. Over 170 units were integrated into cranes and conveyor systems sourced from several different Chinese OEMs. All partners cooperated very well, and NORD’s team was readily available for OEM support throughout the project. From the day Wugang port was opened, all machines have been used to capacity almost all the time, with the drives reliably doing their duty.
Geared motors for demanding conditions
Three very large clamshell unloaders (2,500 t/h) serve the 300,000 dwt berth. These machines incorporate a total of 72 three-stage bevel gear units from NORD. Two massive mobile ship loaders (5,000 t/h) are equipped with 16 three-stage bevel geared motors and a two-stage helical bevel gear unit each. These drives are capable of moving these large systems along the berth on tracks to position them as needed to access various areas of operation. Another 72 three-stage bevel gear units are installed in three bucket-wheel stacker-reclaimers (500 t/h) for the ore stockyards at the port. All geared motors at Wugang feature a heavy-duty housing that makes them suitable for outdoor use and severe weather. Well sealed against moisture ingress and fitted with corrosion- and moisture-resistant components, they provide a high degree of protection against the typical challenges of maritime environments. Special paint coats are applied against the salty atmosphere. These units are also tough enough to resist considerable mechanical shock. Most units come equipped with application-specific optional parts, including e.g. dust- and corrosion-protected brakes, micro-switches for continuous brake monitoring, or double canopies serving as drip covers at the motor fans. Such features make these geared motors even more reliable.
Designed to move large loads without fail
For drives used in port installations, a robust, wear-resistant design also means that geared motors must be constructed to withstand massive forces since the machines they move are faced with very large loads most of the time. All gear units are manufactured from a single housing block – an original NORD development. This design ensures optimal resistance to axial and radial forces as well as high efficiency, high output torques, low-noise operation and minimal maintenance efforts during long service life. NORD can specify and deliver a versatile range of helical bevel geared motors for port machinery, all from in-house production. Solutions for cranes and trolleys feature a wide choice of gear ratios. The manufacturer supplies two or three-stage designs with a hollow or solid shaft as required. Users can choose between models with a foot mount, flange models, and shaft-mounted models. All types are equipped with the same space-saving housing, which allows for easy integration. Though motors used in cranes and trolleys often operate around the clock, some loading facilities may also stand still for certain periods of time. The build standard of the drives ensures that normal operation can be resumed directly after even prolonged phases of this kind, without any special maintenance requirements. Moreover, all models are also available as explosion-protected (ATEX) versions if required.
NORD DRIVESYSTEMS is one of the major leaders in drive technology worldwide - for mechanical and electronic solutions.