Product: IsoTech® parallel slide gate valve
Location: Ontario, Canada
Plant type: Two-on-one combined cycle power plant
Industry: Fossil power
Application: HP steam-main steam stop
Background: The plant had two main steam isolation parallel slide gate valves (PSG’s) installed in this application. Design pressure and temperature for the application is 2350 psig at 1050°F (162 bar at 566°C). They were experiencing severe leakage when valves were required to isolate. From initial plant start-up, the frequency of valve maintenance of up to twice per year per valve. The cost of $40,000 per repair, was a particular concern for the plant. These repairs were strictly limited to disassembly, cleaning and visual inspection, grinding the seats and discs and reassembly. Well before the plant anticipated they were faced with having to replace valve seat rings and discs. The plant management decided to look at their alternatives for an upcoming outage.
Requirement: The plant installed two 12” 2500# C12A ValvTechnologies’ IsoTech® parallel slide gate valves during their spring 2014 outage. The IsoTech® valve was the perfect remedy, as it utilizes a RiTech® chrome carbide hardcoating on the disc and seats, providing a more robust, stable sealing surface at elevated temperatures.The IsoTech® valve is a through-conduit, position-seated design, which protects the valve seats from the flow stream, resulting in a valve that provides zero-leakage and requires zero-maintenance. ValvTechnologies is so confident in its ability to withstand demands of steam isolation, that they back the valve with a four-year performance warranty.
Solution: The valves have been installed and in-service for over two years and have experienced over 270 cycles with zero maintenance required. The valve’s ability to provide zero-leakage has resulted in drastically reduced downtime, which combined with the maintenance cost savings, has presented a two-year return on investment (ROI) on the original purchase/installation cost.
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