The world's largest polymer energy chain

Profile

• What was needed: Energy chain E4.350 from the E4.1 series, aluminium guide trough with floating moving end, and Push/Pull Detection System diagnostic system
• Requirements: Long minimum service life of 15 years without major maintenance effort, continuous operation 365 days a year
• Industry: Silt drainage
• Success for the customer: Close collaboration in the engineering process and creation of an individual solution, extensive laboratory tests to check the suitability of the system for the application, on-time installation of a compact and lightweight energy supply system, low-maintenance and failure-free to date.

Problem

The harbour in Antwerp is the largest port in Belgium. In 2011 alone, more than 187 million tons of freight were handled. In order for the huge container ships, among others, to be able to unload their cargo without any problems, the shipping lanes must always be clear. For this purpose, the navigation channels are dredged and enlarged with special vessels. As the space available for storing the dredged sediments continued to shrink over time, the port authority and the Flemish government decided to invest in a modern silt drainage system as part of the ambitious project "AMORAS", (Antwerpse Mechanische Ontwatering, Recyclage en applicatie van slib).
The coarsely sorted sediments - around 500,000 tons per year - are therefore now pumped through a pressurised pipeline to the plant 4 km away, where they are mechanically drained, processed in an environmentally sound manner and then stored.  The central component of the silt treatment plant is an imposing arch-shaped bridge with a span of around 180 m in the outer area.  Two movable, autonomously operating high-performance pumps are attached to the bridge, which can be rotated through 360°.  The dredge pumps suck about 600 m of sediment or³ silt per hour from the sedimentation basin below and transport it via enormous hoses with a diameter of 300 mm for further treatment. A robust solution had to be found for the energy supply to the pumps that could cope with the dimensions of the project.  All the central components of the huge plant had to be designed for a minimum service life of 15 years. However the requirement profile becomes even more complex. The drainage system has been in operation for about 365 days a year, almost without interruption. Operational safety comes first. There must be no unnecessary maintenance and downtime.

Solution

Today, an extremely robust polymer chain from igus GmbH, Cologne, is used to safely guide the hoses of the system over the entire travel. This is the maintenance-free E4.350 model that is openable from both sides and is part of the exceptionally robust E4.1 series that has proven itself in countless applications. It also shows its versatility in composting and sewage treatment plants, tooling and construction machinery, crane technology and wood processing.
The E4.350 with an inner height of 350mm and inner widths of up to 800mm is the largest polymer energy chain in the world to date. In the most demanding "heavy duty" applications, it can easily guide heavy and, if required, stiff loads and is sometimes highly wear-resistant, corrosion-resistant and resistant to oil and seawater. In order to minimise the rolling resistance, sliding rollers made of the tribo-optimised plain bearing material iglidur, which displays its strength in the most diverse applications, prove themselves as a special design on the crossbars. The friction of the hose in the chain is significantly reduced and stability is guaranteed.
In addition to the energy supply system, a corrosion-resistant guide trough and floating moving ends are used. They serve to compensate for any lateral offset tolerances. The energy chain 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 system builder also decided to invest in an electronic monitoring unit. The diagnostic tool PPDS (Push/Pull Detection System), which is especially useful on long travels, measures the pull/push forces of the energy chain online every four seconds and compares them with a calculated target specification. If malfunctions occur, the system can be stopped automatically with the help of the diagnostic tool in order to prevent damage.

Impressive dimensions: The 360-degree rotating bridge of the silt treatment plant with a span of almost 180 metres.

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

Convincing project competence

The decision for the comparatively light plastic energy supply system was quickly made. Both companies have worked together in a spirit of trust on the engineering process from day one. On the one hand, this concerns the complex design process of the bridge construction. A variety of design drawings have been made available in an uncomplicated manner, depending on the project status. On the other hand, the extensive laboratory tests that took place beforehand were also convincing. "The sustained support for this major project has led to success," says Joury van Gijseghem. "Together we have managed this project from the first day to the last. " 
The plant manufacturer has also drawn on their expertise in assembly. The specialist for energy supply systems built the entire system, which was completely installed on the construction site on schedule by the company's own employees. The plant has been operating smoothly from day one. "We have never regretted the decision to use the plastic energy supply system," concludes Joury van Gijseghem. "Furthermore, it was worthwhile for us to involve the system supplier in the project right from the start. This way, mistakes could be minimised right from the start. “

Detailed view of the connection of the 300 mm pump hose to the pump unit.