| At Birchwood Power station in King George, Virginia, USA, two Vorecon RWE 10 F5 have been running very successfully since 1995 in the drive of 2 x 50% boiler feed pumps. Additionally the plant owns a spare VORECON purchased in 1997.
The machines in operation as well as the spare unit had been properly maintained and visually monitored during site visits by Voith Turbo, USA (VTI) over the past years.
However, it was extremely important to the plant that they be assured of continued excellent service from their VORECONs by completeing the recommended maintenance to the units. They contracted with VTI to perform the recommended overhaul of their drives. The main challenge was the removal and service of the VORECON’s with minimal impact to the customers outage schedule. The maximum time Voith was allowed to have these units out of service was 10 days.
Based on review of trended operating data it was decided to spread the service of the units over 2 years. It was also determined that if VTI would be successful in performing this service we would have to utilize the spare VORECON and exchange the installed units one at a time.
The design of the machine base made removal of the VORECON as a complete unit impossible without major disruption to installed equipment. Removal of the drive motor and boiler feed pump were determined to be too time consuming to be completed within the 10 day window of opportunity. It was determined by the experts that the VORECON would have to be split at the oil reservoir and the main housing would be lifted above the mounting rails of the frame. It could then be moved laterally to the open space available.
In this same way, the spare unit was prepared for the exchange by removing the main housing from its oil reservoir and then exchanged for the unit that was removed for overhauling. This required the installation of temporary lifting and transport structure. To successfully meet the requirements VTI enlisted the services of an experienced millwright and machine moving contractor.
In advance of this exchange service, the spare unit was inspected for condition and readiness for installation VTI’s facility in York, PA. Once inspected, it was held at VTI for just-in-time delivery to site. The laydown of equipment and materials during this outage required almost all crane accessible open floor space. This made off site storage a valuable part of this project.
During the 10 day outage VTI had access to the VORECON beginning of day 3 with a millwright crew of 4 plus a Voith service engineer.
Work on the exchange with the installation of the spare VORECON and alignment of the equipment had been successfully completed on day 8. The customer was able to have this spare machine installed with minimal disruption. Because of Voith’s project management, the customer was also able to concentrate his supervisory resources on other areas during the outage.
The removed unit was returned to VTI in York where it was inspected and overhauled. The overhauled unit will be stored for just-in-time delivery for the next outage scheduled to begin September , 2006. |
