World's largest polymer energy chain

Problem

The port of Antwerp is the largest port in Belgium. In 2011 alone, more than 187 million tonnes of freight were handled. In order for the huge container ships, among other things, to be able to unload their cargo without any problems in the interests of smooth transshipment, the shipping lanes must always be clear. For this purpose, the fairways will be dredged and expanded with special vehicles. As the available areas for storing the dredged sediments continued to shrink over time, the port authority and the Flemish government decided to invest in a modern silt dewatering plant as part of the ambitious project

The coarsely sorted sediments - around 500,000 t per year - are therefore pumped through a penstock to the plant 4 km away, where they are mechanically dewatered, treated in an environmentally friendly manner and then stored. The central component of the sludge processing plant is an imposing arch-shaped bridge with a span of around 180 m in the outdoor area. Two movable, independently operating high-performance pumps are attached to the bridge, which can be rotated 360°. The dredging pumps suck around 600 m per hour³sediments or silt from the settling basin below and transport it via enormous hoses with a diameter of 300 mm for further processing. For the energy supply of the pumps, a robust solution had to be found that could cope with the dimensions of the project. For example, all central components of the huge plant had to be designed for a minimum service life of 15 years. But the requirement profile goes even further. The drainage system is in use almost continuously around 365 days a year. Operational safety comes first. There must be no unnecessary maintenance and downtime.

Solution

To safely guide the hoses of the system over the entire travel distance, an extremely robust polymer chain from igus GmbH, Cologne, is used today. It is the maintenance-free E4.350 model from the particularly robust E4.1 series, which can be opened on both sides and has proven itself in countless applications. It shows its versatility in composting and sewage treatment plants, machine tools and construction machines, crane technology and wood processing, among other things.

The E4.350 with an internal height of 350 mm and internal widths of up to 800 mm is thus the largest plastic energy chain in the world to date. For its use in the most demanding heavy-duty applications, it can easily carry heavy and, if necessary, stiff loads and is sometimes highly wear-resistant, corrosion-resistant and resistant to oil and seawater. In order to minimize rolling resistance, sliding rollers made of the tribo-optimized iglide plain bearing material have proven themselves as a special design on the opening webs, which shows its strengths in a wide range of applications. The friction of the hose in the chain is significantly reduced, thus guaranteeing stability.

In addition to the energy supply system, a corrosion-resistant guide trough and floating carriers are used. They are used to compensate for any lateral offset tolerances that may exist. The energy chain, which is filled with hoses and cables, is always safely guided along its entire length in wind and weather. Despite the difficult operating and environmental conditions, there have been no failures so far.
For reasons of operational safety of the bridge construction, the plant manufacturer has also decided to invest in an electronic monitoring unit. The PPDS (Push Pull Force Detection System) diagnostic tool, which has proven itself above all over long travel distances, measures the pulling/pushing forces of the energy chain online every four seconds and compares them with a calculated target specification. In the event of malfunctions, the system can be stopped automatically with the help of the diagnostic tool in order to prevent damage.

Impressive dimensions: The 360-degree rotatable bridge of the sludge processing plant with a span of almost 180 meters.

One of the two movable pump units of the bridge, in the picture with the swivel arm folded in. Clearly visible: the connection of the hose system and the sliding energy supply chain including guide trough.