Ball Valve
Large Bore Cast Steel Trunnion Mounted Ball Valve — Electric Actuated Water Supply & Transmission Service
Specification
Details
Ball Valve Technical Overview
Large bore trunnion mounted ball valves with electric actuation are selected for full-bore isolation service in large-diameter water transmission mains, reservoir control, hydropower station isolation, and municipal water supply systems where automated remote operation, SCADA integration, and reliable long-term performance under sustained pipeline pressure are required. The electric actuator provides precise position control and continuous position feedback to water system control centers — enabling remote monitoring and operation of transmission pipeline sectioning valves and reservoir isolation duty from centralized SCADA systems.
Bypass valve assemblies are standard for large-bore ball valves at DN600 and above, providing pressure equalization across the main ball before opening to eliminate the high differential pressure that would otherwise cause seat damage, actuator overload, and erosive flow through a partially open large-bore valve. The bypass valve opens first to equalize upstream and downstream pressure, then the main ball opens under near-zero differential pressure — protecting seat integrity and extending service life in large-bore water transmission applications where valve cycling frequency may be low but seat condition is critical for long-term leakage performance.
Blue epoxy coating is the standard surface treatment for water pipeline service, providing corrosion protection for above-ground and vault-mounted water transmission installations. Electric actuation is preferred over hydraulic and pneumatic alternatives for water utility installations where compressed air and hydraulic infrastructure are not available, and where clean, maintenance-free operation with direct electrical interface to SCADA and building management systems is preferred. Design standards API 6D and GB/T 28776 govern large bore trunnion mounted ball valves for water supply and transmission pipeline service