Retrofit service in the Kleinsteinbach sewage treatment plant

The Kleinsteinbach sewage treatment plant operated by the Mittleres Pfinztal and Bocksbachtal Sewage Board reliably removes solids, fecal matter and all kinds of organic compounds from the community's wastewater on a daily basis. With the capacity to serve 32 000 inhabitants, it is one of Germany's medium-sized sewage treatment plants.

In November 2014, the operator of the sewage treatment plant decided to arrange a preventive diagnostic check of its drive technology to ensure continued system availability. We used a flexible video endoscope to assess the condition of gearing components and bearings. The gear unit does not need to be disassembled for this purpose. The endoscope probe is introduced into the gear unit through small openings and the high-resolution camera provides razor-sharp images of the interior. A visual inspection of the bearings and gear teeth, combined with video footage of the tooth flanks, ultimately enables a conclusion to be drawn about the condition of the drives. Signs of damage such as micro-pitting, pitting and fretting can be identified at an early stage and appropriate measures decided on.

We offer further analysis options as part of a "Quick Check", during which one of our specialists records and assesses condition-related variables such as the overall condition of the exterior, running noise, oil level/quality etc. This is a quick and reliable way of obtaining important information about the drive technology's condition – the basis for optimizing in-house maintenance.

Based on the overall condition of the gearing components and the state of the gear unit lubricant, recommendations can be made for the drives inspected. The gear unit of the screw pump on the interim lift system already exhibited significant signs of wear. The gear and pinion of the output stage in particular had large pitted areas, which could develop into larger flank ruptures and ultimately result in the total failure of the drive unit. Further drives with only minimal damage, such as the ones on the intake pumping station and the scraper, were classified as not critical.

The diagnostic check ultimately prompted the operator to replace the existing gear unit (manufactured by a third party) with one of our industrial gear units. This involved replacing the original helical-bevel gear unit and belt drive with a three-stage helical gear unit. This unit was connected to our energy-efficient DRN motor using a motor adapter with integrated, torsionally flexible jaw-type coupling. It was attached to the worm shaft using a pin coupling with elastomer elements to compensate vibrations and jolting. In addition, a backstop on the gear unit absorbs the reverse acceleration caused by the water gushing back when the motor is switched off. Based on a gear ratio of 36, the nominal output torque of the X series gear unit is 8500 Nm. The independent industrial gear unit platform includes both helical and helical-bevel gear units. The wide range of accessories and options and the possibility of customization are perfect for meeting water and wastewater management requirements.