All repairs are completed under our QA program and ensure valves meet all OEM specifications. NWS provides complete repair services for all types of safety/ relief valves, including:
Dresser/ GE-Consolidated - PSVs, MSSVs, PORVs and ERVs
Crosby - PSVs, MSSVs, MSSRVs, and CARVs
Target Rock - Pilot operated 2 and 3-stage MSSRVs
Dikkers - MSSRVs
Other OEMs - Balance of Plant Steam/ Water/ Air/ Valves
NWS records spring dimensions as part of each repair. This includes measurements of free height, squareness, and parallelism. In addition, NWS also offers spring rate testing, and recommends it as an extra assurance that the spring has not degraded from years of service. Using our calibrated spring rate test machine, we can verify that the spring rate is within OEM specifications.
Disc oxidation is an additional, optional repair process for some MSSVs. This process minimizes the risk that the disc seat will stick to the nozzle seat during service. After disc seats have been lapped and polished, the discs are placed into our temperature controlled, high-pressure oxidation chamber and exposed to high pressure steam for a specified period of time. Process data (i.e. temperature and pressure) are recorded using our specially calibrated instruments. Upon completion of this process, an oxidation layer is present on the disc seat.
Nozzle passivation is an additional, optional repair process for some MSSVs. This process minimizes the risk that the nozzle seat will stick to the disc seat during service. After nozzle seats have been lapped and polished, the nozzles are submerged in a chemical mixture for a specified period of time. Upon completion of this process, an oxidation layer is present on the nozzle seat.