Defying wind and weather

Peru is one of the fastest growing countries in Latin America. Callao, as major seaport, plays a prerequisite role in ever growing cargo handling. Heavy duty encoders are crucial when it comes to smooth loading and unloading of cargo from giant vessels.

Important transshipment point

Callao is the main seaport of Peru and a significant transit point for the fast growing cargo traffic between Asia and South America. In 2010, it handled more than 1.3 million TEU. The main share is held by the terminal DP World Callao, Muelle Sur, which has a capacity of 850,000 TEU. A water depth of 16 meters allows for landing and embarking of ships of the post-Panamax class, with a maximum cargo capacity of 8,000 TEU.

The starting point for terminal upgrade was in May 2010. Today, there are six STS cranes, with a maximum capacity of 28 TEU every hour, and 18 RTG, all equipped with the Baumer Hübner HeavyDuty encoders from the Baumer Group competence center for HeavyDuty applications. Deployed at spreaders, crane trolleys and chassis, they ensure reliable and trouble free operation.

Maritime climate poses a challenge to all components

Harbor cranes are in action 24 hours a day and permanently exposed to corrosion by saltwater and salty air. These conditions call for outstanding products, so heavy duty encoders, specially conceived for continuous operation, strong mechanical impacts and a corrosive ambiance, are the products to choose when it comes to long-term proven reliability in cranes and port installations.

The cable pull used for lifting and lowering the spreader is exposed to maximum stress and strain. The cable of a twin spreader is expected to handle loads of 65 tons, and have lifting speeds of 100 meters per second and lowering speeds of 180 meters per second.

For DP World Callao, Muelle Sur, each crane requires two hoisting drives of 620 kilowatt, each manufactured by the company Franz Wölfer Elektromaschinenfabrik. Shaft diameter is 95 millimeters. One drive is intended as an emergency drive. Most demanding requirements are on continuous performance. Planned maintenance is only twice a year, and the system is expected to run without any unexpected breakdown.

Consequently, the encoders deployed must be ultra reliable to meet the application requirements.

High precision

Precision is another decisive criterion, since the encoder has to provide dependable feedback on the spreader’s lifting and lowering speed.

The incremental HeavyDuty encoder HOG 220, with through hollow shaft, will cope with all these challenges and fits any shaft diameter between 80 and 115 millimeters. The robust, thick walled housing, with special surface finish, provides electric insulation, saltwater resistant primary coating and a second top coat sealing. This way, the housing is compliant to category C4 of ISO 12944. Further, the anti-corrosion protection does not only include the housing, but comprises the other components as well. Cable glands, connector outlets and screws also have to give proof of their saltwater resistance.

Bearing blocks

Thanks to its robustness, the encoder will also endure very high axial and radial loads. 450 Newtons axial and 700 Newtons radial are effortlessly mastered by the bearing blocks. Insulated against inductive shaft currents up to 0.7 kilovolts, they are reliably protected from damage. Another design benefit is eased electrical connection by the proven terminal box rotatable through 180 degrees. A protective lid and encapsulation will prevent the electronics from any damage by dust or condensation while the cover is opened for installation.

New product platform

The latest development in the HeavyDuty portfolio is the HOG 86 platform. The compact design and flexible installation capabilities make the encoder perfect for speed and position feedback at cranes, or for drive control tasks at lifting platforms.

The resilient aluminum housing with saltwater resistant top coat compliant to category C4 and ISO 12944 ensures long-term IP 66 protection – even at the shaft. Dual bearings provide a load capacity reserve up to 300 Newton radial and 200 Newton axial. There is no need to outline again that other components, such as cable glands, outlets and screws, are also saltwater proof.

 

To read the full article download PDF

Wolfgang Jarausch, senior marketing manager, Baumer Group Product Segment Motion Control and Kai-Hans Otto, head of design engineering, Baumer Hübner GmbH, Berlin, Germany
Edition: Edition 54

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