Boltight's Hydraulic Closure System Simplifies Blue Contact Check
General Electric engineers working on a (GE) D12 steam turbine used Boltight's Hydraulic Closure System (HCS) to carry out a 'blue contact check' and assist with final reassembly.
Walsall, United Kingdom, August 18, 2015 (Newswire.com) - General Electric engineers working on a (GE) D12 steam turbine at EDF's CCGT power generation plant in Blénod-lès-Pont-à-Mousson, France, used Boltight's innovative Hydraulic Closure System (HCS) to quickly carry out a 'blue contact check' and assist with final reassembly. This flexible system is now proving increasingly popular for carrying out different types of servicing work, in addition to conventional 'Tops on: Tops off' clearance checks.
Boltight's complete system comprises specially designed hydraulic nuts, a hydraulic hose arrangement, a hydraulic pump, spares and a health and safety operating manual. The hydraulic nuts locate on the existing bolts and are screwed down on to the turbine casing. These nuts are linked hydraulically using flexible hoses and quick acting nipples and couplings. They are connected to an air driven hydraulic pump.
When pressurised, the closure system stretches the bolts quickly to compress the casing evenly and accurately for performing the clearance, distortion and alignment checks. This saves time during an outage and provides accurate and repeatable results. The system also delivers significant time savings during final turbine assembly and valve cover tightening. It compliments the use of traditional bolt tightening methods (e.g. heating and torque) used for turbine disassembly and reassembly and laser alignment methods. The tools can be operated by a customer's own site personnel with minimal training.
Due to time constraints during the outage at Blénod, GE's engineers decided not to perform a conventional 'Tops on: Tops off' but rather to carry out a 'blue contact check' to identify potential gaps before final reassembly of the D12. The hydraulic nuts were concentrated on specific areas of the casing that were a cause for concern. In total 44 hydraulics nuts were used on a horizontal joint that had 80 bolts. Using Boltight's HCS ensured the whole process took just five hours to complete, including engineer training.
Like many of Boltight’s customers, GE Energy has chosen to rent the HCS rather than purchase it outright. Boltight's warehouse team can call off a complete kit at short notice that is configured to GE's specific requirements. Hydraulic nuts in a range of sizes to fit standard turbines are always kept in stock, together with pumps, hoses and fittings.