Energy chain system instead of cable drum

Smooth operation of the wastewater treatment plant since 2000

The Waldbröl-Brenzingen wastewater treatment plant, which was built in early 1970 and significantly expanded in 1991, is one of 38 wastewater treatment plants operated by the Aggerverband in the Bergisches Land region. It treats the wastewater produced in large parts of the town of Waldbröl and is designed for 10,200 population equivalents. An energy supply solution now had to be found for the mobile scraper of a clarifier. The Aggerverband decided against the conventional solution with cable drum and in favour of an energy supply from the lbt flizz® system from igus®. The result: the system at the sewage treatment plant has been working without any failures since 2000.

Profile

What was needed: lbt flizz® system, E2 series energy chain, type 250.07.100.0, guide trough, chainflex® special cables from the CF9, CF10 and CF 31 series, floating moving end to compensate for lateral movements
Requirements: severe weather conditions (sun, frost, rain), aggressive gases such as hydrogen sulphide, leaves and snow, trouble-free operation despite 24/7 operation
Industry: sewage treatment plant
Success for the customer: reliable energy supply system in adverse conditions, drastic reduction in maintenance costs

The initial situation at the secondary clarifier

Problem

Within the wastewater treatment plant, the wastewater first enters a screening system with several filter stages and then a primary clarifier, where the sludge settles before being extracted. In two secondary clarifiers, the continuously fed biological sludge is evenly distributed by a scraper and removed from the tank via a pumping station after settling. One of the two secondary clarifiers is rectangular and equipped with a longitudinal scraper, which moves at a speed of 1 metre per minute via a gear drive and continuously distributes the sludge in the 38 metre long and 3.15 metre deep basin - 24 hours a day, 365 days a year. Like the pumps below the water level, the scraper requires energy and control signals.
As the energy supply system required for this will operate outdoors, it must not only be resistant to sun, frost and rain. Extremely aggressive gases such as hydrogen sulphide are also produced during wastewater treatment and pose a major challenge. Leaves and snow can also impair the movement of the cables - precautions must be taken here. And at the same time, you have to be sure that the system runs smoothly around the clock. This is because every unscheduled deployment of the on-call service incurs additional internal costs - this is precisely recorded in the Aggerverband.
Originally, a cable drum was used for this task. This solution was not very satisfactory for those responsible, as the cable performed a slight twisting movement with every forward and backward movement, which contributed to increased wear.

Solution

After the operator was looking for a suitable solution for the system, he found what he was looking for in the energy supply programme from igus®. With the lbt flizz® system, igus® offers a weather-resistant energy supply system that can be modularly adapted to the respective operating conditions. The system is also a good alternative in terms of price, especially in comparison to festooning solutions. The proven chain of the igus® series E2, type 250.07.100.0, was used as the energy chain. This runs in a guide trough, which consists of extruded guide profiles attached to a support frame. As the trough is closed at the top, neither snow nor leaves can impede the movement of the filled energy chain in the guide trough. A total of 38 metres of guide trough were installed in the secondary clarifier. The chainflex® special cables used in it are approx. 20 metres long; in addition to the electrical cables for the three pumps and the traversing motor, the trough also houses 16 signalling cables and a Profibus cable. The individual igus® chainflex® special cables of the CF9, CF10 and CF 31 series have a TPE outer sheath and can be used in a temperature range from -25° to +100° with a minimum bending radius of 5xd.
Lateral displacement of up to 150 mm is always to be expected with this type of longitudinal clearer. To compensate for these lateral movements, igus® developed a cost-effective floating moving end and installed it on the moving arm of the scraper bridge.
Both the plastic components and the metal parts are permanently protected against corrosion.

Maintenance costs drastically reduced with lbt flizz®

The system has been running without any problems since it was installed in 2000. Maintenance costs have therefore been drastically reduced. It is therefore not surprising that the Aggerverband is satisfied with this solution. Those responsible also give the service from igus® good marks. Reinhard Braun, Head of Electrical Engineering at the Aggerverband, comments: "Our contacts have always responded quickly and unbureaucratically."
The lbt flizz® system has proven itself under adverse environmental conditions, and not only in this application. All the materials used in the system are corrosion-resistant and weatherproof. A correspondingly large number of other possibilities have already been realised, for example in rainwater overflow basins or harbour cranes, which have to meet extreme corrosion protection requirements. As the system components are also resistant to common chemicals, greases and solvents, igus® also supplies the lbt flizz® system to manufacturers and operators of galvanising plants and other chemical engineering facilities.

Here you can find the products used

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