repairs in 2017
repair experts at your service
at DV Group
A process guaranteeing a 100% functional product
DV Group expertise in gear reducer repair is divided into
- Infrared thermography: abnormal heating (loading and lubrication areas).
- Measuring vibrations: faults with meshing, bearings, jarring of mechanical parts.
- Endoscopy Inspection with housing open: teeth, shafts, surfaces, sealing.
Technical procedures / test procedures:
Procedure before dismantling
- Mechanical inspection: general condition, casing, shaft, etc.
- Check lubrication and cooling circuits.
Dismantling inspection procedure
- Geometric checking of casing. Inspection of tooth contact surfaces.
- Search for common deteriorations (pitting, spalling, chippings, etc.).
- Metrological check of casing, flanges and shafts: bearing seatings, joint surfaces.
- Dyeing of shaft connection radii and keyways.
- Magnetoscopy inspection of all gear teeth.
- Inspection of heating, sealing and lubrication (metal tearing, general appearance, leakage, etc.).
- Replacement of bearings, joints, sealing.
- Adjustment of the bearing play and teeth contact surfaces.
- Repair: chromage, ringing, refilling.
- Recording of defective gears using the model.
- Repair of the ends of shafts and housings using a dedicated soldering or stapling process.
- Replacement and adaptation of lubrication units (manometer, flow meter, pressurestat, filters) and piping.
Testing / validation procedure
- No-load tests running on a platform up to 1,600 kW.
- Reduction validation, output speed.
- Testing of sealing and assembly position: vents.
- Choice of lubrication adapted according to criteria: load, temperature, assembly position, process.
- Measurement and vibratory signature.
- Diagnosis and testing history.
- Traceability produced by: machine number / customer number / DV GROUP number.
- Test sheet and qualification/test certificate.
Case study :
Need / Context
Glass producers must rebuild their furnaces every 15 years. The refractory brick component needs to be replaced to ensure its tightness of fit. During this shutdown, the OI Manufacturing site in Ardèche refurbishes the related equipment. Glass production has a reliability requirement, and must be able to ensure long periods without breakdown or maintenance stoppage.
To achieve these availability and efficiency goals, the glass producer entrusts us with the removal, overhaul and refitting of its fifteen 750 KW - 50 Hz medium-voltage fan and compressor motors. For one month (800 hours), our teams from the various electromechanical sites in Grigny, Cambrai and Lyon mobilised to process these products and meet the deadlines imposed by our customer. We added DV GROUP know-how to the flawless organisation demanded by this project. OI Manufacturing has atypical 750 KW - 50 Hz medium voltage motors with plain oil bearings instead of ball bearings. These bearings carry a higher radial load and have a longer life than bearings. However, they require a specific expertise.
- Deadlines met - Furnace restart with products 100% tested and 100% functional
Need / Context
The European Organization for Nuclear Research, commonly known as CERN, is the largest particle physics center in the world. CERN is located in Switzerland, near Geneva. On an ad hoc basis, CERN makes technical stops in order to recondition their equipment. Following the last stop, a lubrication problem on two cooling tower reducers is detected.
CERN wants a SIEMENS / FLENDER agreed repair partner which leads them to contact us. After many exchanges with the customer, particularly about the safety of this kind of repairs, CERN entrusts us with the project. Our customer asked us to overhaul these 2 FLENDER industrial reducers but also to supply and replace the lubrication pump within a period of 4 weeks. For a month, our teams were mobilized to treat these products and meet the deadlines our customer required.
- Deadlines respected - Preparation of a detailed report describing the different operations carried out - Convinced by the results of this first collaboration, CERN wishes to entrust us with the overhaul of 6 to 8 other reducers for the coming years.
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