III. Feature Description

A. Trunnion-Mounted Ball Design: Stability Under Extreme Pressure

• Pressure Load Distribution: The ball is secured by upper and lower trunnions, which absorb the thrust generated by media pressure—transferring loads to the valve body rather than the seats. This eliminates seat deformation and uneven wear, even under PN100 high pressure, ensuring consistent sealing performance over 100,000+ cycles.
• Low Operational Torque: Trunnion supports and self-lubricating bearings reduce friction between the ball and seats, lowering operational torque by 30–50% compared to floating ball valves of the same size. For DN600 PN100 valves, this enables manual operation with a worm gear operator, eliminating the need for expensive electric actuators in some scenarios.
• Bidirectional Sealing: The fixed ball alignment ensures uniform contact between the ball and dual seats, enabling reliable sealing in both flow directions—simplifying pipeline design and eliminating the need for check valves.

B. Three-Piece (3PC) Forged Body: Durability & Maintenance Flexibility

• Forged Integrity: Forging eliminates internal defects (porosity, shrinkage) common in cast bodies, delivering a dense, uniform grain structure that enhances tensile strength and resistance to cyclic pressure loads. Forged SS304/316 bodies withstand thermal shock and pressure surges without deformation—critical for high-temperature steam or cryogenic LNG service.
• On-Line Maintenance: The three-piece design (body, bonnet, end flanges) allows internal components (ball, seats, trunnions) to be inspected, repaired, or replaced without removing the valve from the pipeline. This reduces downtime by 60–70% compared to one-piece or two-piece valves, a key benefit for continuous-process facilities like refineries or water treatment plants.
• Modular Versatility: End flanges can be configured with different standards (ASME/GB) or sealing surfaces (RF/RTJ) on the same valve, accommodating non-standard pipeline setups and reducing the need for custom adapters.

C. Wide Temperature & Pressure Adaptability: Versatile Service Range

• Cryogenic Compatibility: With low-temperature steel (A350 LF2) body and PTFE seats, the valve operates reliably at -196℃—suitable for LNG storage and transfer, liquid nitrogen systems, and other cryogenic applications. The forged structure maintains toughness in low temperatures, preventing brittle fracture.
• High-Temperature Resilience: Graphite seats and F22 chrome-molybdenum steel body enable service up to 600℃—ideal for boiler steam lines, high-temperature oil processing, and power generation systems. Graphite’s inherent heat resistance ensures sealing integrity even under prolonged exposure to high temperatures.
• High-Pressure Stability: PN100 rating (10.0MPa) makes the valve suitable for high-pressure pipelines, wellhead equipment, and hydraulic systems. The trunnion design and forged body prevent blowout and leakage, meeting safety requirements for critical high-pressure service.

D. Advanced Sealing Systems: Reliable Closure & Emission Control

• Self-Compensating Seats: Stainless steel springs preload the seat inserts, ensuring constant contact with the ball. As the seat wears over time, the spring automatically pushes the seat forward—compensating for wear and maintaining sealing force. This extends seat life by 50% compared to non-compensating designs.
• Dual-Seal Options: EPDM/PTFE seats for general and chemical service deliver bubble-tight Class IV sealing, while graphite seats for high-temperature service provide Class V sealing—covering most industrial media requirements. For sour service (H₂S-containing media), optional metal-to-metal seats with Stellite overlay ensure corrosion and wear resistance.
• Low Fugitive Emissions: Multi-layer graphite packing meets ISO 15848-1 Class AH standards, limiting methane leakage to ≤100ppmv—complying with EU Industrial Emissions Directive and US EPA regulations, reducing environmental impact and avoiding fines.

E. Flexible Actuation: Tailored to System Requirements

• Manual Operation: Cost-effective for small-to-medium diameter valves (DN50-DN200) or systems with infrequent operation. The anti-slip handwheel and worm gear operator (for large valves) enable easy, tool-free control.
• Pneumatic Actuation: Fast, reliable operation for automated systems (e.g., batch processing lines). Spring-return actuators provide fail-safe functionality (open or closed on air failure), enhancing safety in hazardous environments.
• Electric Actuation: Ideal for remote or precision control (e.g., SCADA-integrated systems). Torque limiting and position feedback features prevent overloading and enable real-time monitoring of valve status.

IV. Manufacturing Process & Quality Control

A. Raw Material Procurement & Inspection

• Material Sourcing: Forged SS304/316 blanks, duplex steel, and low-temperature steel are sourced exclusively from ISO 9001-certified suppliers, with each batch accompanied by a Material Test Certificate (MTC) detailing chemical composition, mechanical properties, and heat treatment history.
• Material Verification: Incoming materials undergo spectral analysis (XRF) to confirm chemical compliance with ASTM/GB standards. Tensile, yield, and impact tests are performed on sample specimens—e.g., SS304 must meet tensile strength ≥515MPa and impact toughness ≥27J at -20℃.
• Non-Destructive Testing (NDT): Forged components (body, bonnet, ball, trunnions) undergo ultrasonic testing (UT) to detect internal cracks or inclusions, and magnetic particle testing (MPI) to inspect surface defects. Only defect-free materials proceed to machining.

B. Forging & Heat Treatment

• Precision Forging: Steel billets are heated in a controlled-atmosphere furnace to 1100–1250℃, then forged into body, bonnet, ball, and trunnion shapes using hydraulic presses (500–5000 tons). The forging ratio is maintained at ≥3:1 to ensure dense grain structure and uniform mechanical properties.
• Heat Treatment:
  • SS304/316 components: Solution annealing (1040–1150℃, water-cooled) to restore corrosion resistance and relieve forging stress.
  • Low-temperature steel (A350 LF2): Normalizing and tempering (890–920℃, air-cooled; 620–680℃, furnace-cooled) to enhance low-temperature toughness.
  • Chrome-molybdenum steel (F22): Normalizing and tempering (900–940℃, air-cooled; 670–730℃, furnace-cooled) to improve high-temperature strength.
• Descaling & Cleaning: Forged parts are shot-blasted to remove surface oxide scale, then cleaned with ultrasonic baths to eliminate residual contaminants.

C. Precision Machining

• Body & Bonnet Machining: CNC lathes and mills process flange faces, seat pockets, and trunnion bores. Flange faces are machined to flatness ≤0.02mm/m and surface roughness Ra 1.6μm. Seat pockets are honed to coaxiality ≤0.01mm relative to the bore, ensuring uniform ball-seat contact. Trunnion bores are precision-drilled and reamed to fit bearings with clearance ≤0.02mm.
• Ball Machining: Forged balls are ground to spherical accuracy ≤0.005mm and lapped to Ra ≤0.4μm. Full-port bores are machined to match pipeline dimensions, with no sharp edges to minimize flow turbulence. HF hardening or Stellite overlay is applied to the sealing surface for wear resistance.
• Stem & Trunnion Machining: Stems are turned and ground to diameter tolerance ±0.01mm and polished to Ra ≤0.4μm. Trunnions are machined with precision threads for bearing installation, ensuring smooth rotation.

D. Assembly & Comprehensive Testing

1. Component Cleaning: All parts (body, ball, seats, stem, packing) are degreased and ultrasonic-cleaned to remove oil, debris, and metal particles—preventing contamination of sealing surfaces.
2. Assembly Sequence: Trunnion bearings are installed first, followed by the ball, stem, seats (with preloaded springs), packing, and bonnet. Fasteners are tightened in a crisscross pattern to uniform torque (per ASME B18.2.1) to ensure even clamping force.
3. Pressure Testing:
   • Hydrostatic Shell Test: 1.5× rated pressure applied to the body cavity for 30 minutes—no leakage, deformation, or pressure drop permitted.
   • Hydrostatic Seat Test: 1.1× rated pressure applied to each seat (bidirectional) for 15 minutes—leakage measured via bubble counting, complying with ANSI/FCI Class IV/V.
   • Pneumatic Test (Optional): 0.6MPa air pressure applied to the body and seats for 10 minutes—no audible leakage permitted.
4. Operational Testing: The valve is cycled 50 times (open-close) to verify smooth operation, consistent torque, and correct actuator performance (for pneumatic/electric models).
5. Specialized Testing:
   • Cryogenic Test: For low-temperature models, testing at -196℃ to verify sealing and structural integrity.
   • High-Temperature Test: For high-temperature models, testing at 600℃ to confirm seat performance.
   • Fugitive Emissions Test: ISO 15848-1 Class AH compliance verified with methane and flame ionization detector (FID).

E. Final Inspection & Packaging

• Visual Inspection: Each valve is inspected for surface defects (scratches, dents), proper machining, and correct marking (DN, PN, TIANYU logo, standard certifications). Valves with surface scratches deeper than 0.05mm are rejected.
• Documentation: Each valve is shipped with a Documentation Package including MTC, Hydrostatic Test Certificate, EN10204 3.1/3.2 Certificate, and CE PED Declaration of Conformity.
• Packaging: Valves are packaged in plywood crates with foam insulation to prevent damage during transportation. Flange ends are capped with plastic protectors, and actuators are wrapped in waterproof film. Crates are labeled with handling instructions and product information for safe delivery.