III. Features Description

• Trunnion-Mounted Stability: The ball is fixed by upper and lower trunnions, transferring fluid pressure to trunnion bearings instead of the seat. This avoids ball displacement under high pressure, preventing seat wear and ensuring consistent sealing—critical for gas pipelines where leakage risks safety.
• Metal-to-Metal Sealing: Seats and balls are coated with tungsten carbide via HVOF (High Velocity Oxy Fuel) spraying, achieving hardness up to HRC72 and bonding strength ≥10,000Psi. This resists wear from abrasive media (e.g., gas with particles), ensuring zero leakage even after 10,000+ cycles.
• Gear Operation Convenience: The gear drive reduces operating torque by 50% compared to direct manual operation, allowing one person to control large-diameter (up to DN1500) valves. Its self-locking design prevents accidental rotation from pipeline vibration.
• Safety & Reliability: Integrates anti-blowout stem (prevents ejection under extreme pressure), cavity pressure self-relief (avoids overpressure damage), and fire-safe design (API 607) to maintain sealing if soft components fail in a fire. Emergency sealant injection ports enable on-site leak repair.
• Forged Structure Integrity: Forged bodies (instead of cast) eliminate internal defects, enhancing structural strength in high-pressure environments. This avoids leakage points common in cast valves, making them ideal for critical gas/oil lines.

IV. Manufacturing Processes

• Forging & Material Preparation: A105/F316 materials are forged to form dense, defect-free bodies. Ultrasonic testing detects hidden cracks, ensuring structural integrity for high-pressure use.
• Precision Machining: Ball and seat sealing surfaces are CNC-machined to Ra ≤0.8μm. Metal-to-metal seals undergo “one-to-one” grinding to ensure perfect contact, while PTFE seats are pre-loaded with springs for consistent pressure.
• HVOF Coating (Metal Seats): Tungsten carbide is sprayed onto seat and ball surfaces at high velocity, forming a 0.3~0.5mm thick coating with HRC68~72 hardness. This process ensures uniform coverage and strong bonding to resist wear.
• Assembly & Testing:
  • Gear components are calibrated to 0.1~0.2mm meshing clearance for smooth torque transmission; trunnions are press-fitted and welded to the body for stability.
  • Hydrostatic Test: Body tested at 1.5×rated pressure (e.g., 6.4MPa for PN40) for 30 minutes; seat tested at 1.1×rated pressure to confirm no leakage.
  • Fire-Safe Test: Exposed to 750℃~1000℃ fire, then tested for post-fire sealing to meet API 607.