Underground Ball Valve

Naishi underground ball valve is developed by our engineering team based on more than a decade of experience in high-pressure valve design and manufacturing. It is designed and manufactured in accordance with the latest international standards, and is mainly used in long-distance transmission pipelines for petroleum, natural gas, and city gas systems. Its unique structure and design take full account of pipeline stress resistance, corrosion protection, safety, weather resistance, and long-term reliability.

Structure Features
Emergency Sealing
Grease injection valves are installed at stem and seat areas for secondary sealing in case of leakage, equipped with internal check valves to prevent backflow.
High-Strength Valve Body
Split-body design with reinforced wall thickness and X-ray tested welds ensures strength, durability, and ease of maintenance.
Double Block & Bleed (DBB)
Allows cavity pressure release and medium discharge when fully open or closed. Self-relieving seats handle overpressure automatically.
Low Operating Torque
Hardened ball and stem with low-friction bearings reduce torque and improve ease of operation.
Cavity Venting
Vent valves enable cavity flushing and gas discharge, especially for valves DN200 and above
Reliable Sealing
Dual-seal design (soft + metal), spring-loaded seats, and fire-safe graphite rings ensure tight sealing under all conditions.
Fire-Safe & Anti-Static
Certified to API 6FA/API 607 with anti-static devices per BS 5351 for safety in hazardous environments.
Material Excellence
Materials comply with API, ASME, GB, NACE standards, tailored for different media and corrosion conditions.
Extended Stem & Accessories
Extended stem and grease lines for easy ground-level access in buried applications.
Flexible Actuation
ISO 5211 mounting for manual, electric, pneumatic, or hydraulic actuators.