HydroSele® success at Italy's largest pumped storage plant
James Walker’s HydroSele®S has proved its superb sealing efficiency by running maintenance free for over two years at ENEL’s massive Entracque pumped-storage hydroelectric scheme in Italy.
The HydroSele cartridge unit replaced a troublesome mechanical seal that had to be changed frequently on the plant’s Unit 9 turbine — a costly exercise that created an unacceptable loss of generating capacity.
With a working water head of 600m from the Rovina dam high in the Maritime Alps, the pumped storage scheme has nine vertical multi-stage reversible Francis turbines.
The Unit 9 turbine supplied by Ansaldo has a 680mm diameter shaft running at 600rpm to produce 130MW. It was originally fitted with a spring-energised conical wedge mechanical seal that leaked up to 300 litre/min, causing plant flooding.
“This was an obvious application for our innovative HydroSele cartridge unit,” stated Marco Nogarin, senior representative of James Walker in Italy. “We estimated that at this site, the HydroSele would pay for itself in less than two years, in terms of maintenance costs, turbine downtime and power absorption”.
To work with the 600m head of water, the system was designed with a relief line that reduced the pressure at the seal interface to 10bar, making it perfectly suitable for HydroSele operation.
The cartridge unit and adapter plate from James Walker were installed by ENEL maintenance staff in spring 2006, supervised by Marco Nogarin. Since then, the HydroSele has operated perfectly and adjustment-free with a carefully controlled leakage rate of only 15 litre/min. This is about one-twentieth of the water leakage from the troublesome mechanical seal it replaced.
Explained Tim Smith, James Walker’s business development manager for rotary cartridges: “The dramatic savings our HydroSele has achieved for ENEL at Entracque shows that we can reduce maintenance costs and improve uptime on high-pressure pumped storage systems worldwide.”
The innovative feature of HydroSele is the way its sealing elements operate within the fully-split cartridge. Two elements work back-to-back with filtered flush water introduced between them. In operation, the elements are pressure balanced and run on a hydrodynamic fluid film that provides high speed capability with a low level of controlled leakage.
James Walker & Co Ltd is a member of the James Walker Group. This global manufacturing group, with an annual turnover in excess of £125-million (€180-million), operates through two strategic business units: Sealing Products & Services, and Rail Systems & Products. It has 50 production, engineering, distribution and customer support sites worldwide and sells in over 100 countries.
PHOTOCAPTION: HydroSele® S is the innovative shaft sealing system from James Walker that cuts maintenance and improves the reliability and profitability of Francis and Kaplan water turbines in hydropower plant. Simple to install and adjustment free, this split-type cartridge offers a long and reliable service life. When maintenance is eventually required, it can be economically refurbished on site in just a few hours to return it to good-as-new condition.
30 Sep 08
Latest News |
Archive
