FIGHTING CHEMICAL ATTACK

摘要

During a nine-week outage at the Navajo Generating Station power facility, several critical pump systems and components were serviced and repaired. The facility's Allis Chalmers WSDD 66 x 78-inch split case cooling tower recirculation pump and Pratt butterfly valves provide cooling water to the Unit 2 cooling tower. Achieving good water chemistry in cooling towers is challenging. A host of chemicals are required to maintain pH and to keep algae growth to a minimum but the required chemicals are not always compatible with pump and valve materials. Quadna was asked to repair the two 66-inch diameter Pratt butterfly valves. Each valve weighed close to 12,000 pounds and had been in-service for more than 30 years with only the seals being replaced during that time.