HYDROELECTRIC FIELD MACHINING PROJECT - New Turbine Installation

Overview

Furmanite was recently hired to perform in situ machining on the new construction of a three turbine hydroelectric generation power plant installation on the Ohio River. The power plant houses three horizontal 29.3-MW bulb-type turbines, and generating units, with an estimated total rated capacity of 88 MW at a gross head of 25 feet. The Stay Cone flanges and associated mating parts were manufactured and machined in the OEM's workshop facilities and transported to the site. Due to the size, configuration, mechanical handling, transportation complexity, and installation limitations the final machined finishes required precise on-site machining to correctly align the enormous mating surfaces. With a proven history of performance, Furmanite's Integrated Mechanical Services Division, a worldwide leader in large dimension field machining, was hired for the in-situ field machining of the Stay Cone Vertical Flanges.   All three bulb turbine units were to be completed with the final required 3mm to 5mm of stock removal in the mating flange faces in which the massive flanges measured 17 feet inside diameter by 19 feet outside diameter.           Solution and Implementation Furmanite was hired by the general contractor for immediate assistance to resolve the misalignment issues which were creating significant assembly delays, and was having a major effect on the entire project delivery schedule. It was Furmanite's determination that with some engineering modifications to an existing large flange facing machine the customer's machining requirements could be completed accurately. Within a 10-day timeframe Furmanite engineered the modifications for the machine, manufactured the parts, and mobilized to the site.  Watch the video, here. Results   The machine was set to known datum points using laser tracker equipment. Machining was carefully undertaken with measurements taken frequently. All three unit Stay Cone Flanges were successfully machined and completed within a 21-day period. The tolerances achieved included perpendicularity over the full 19 feet Outside Diameter to within 0.2mm (0.0078"), and the overall flatness required was +/- 0.15mm (0.0059").