III. Features Description

• Bellow Seal Zero Leakage: The 304 stainless steel bellow is welded to the stem and bonnet, creating a permanent seal that eliminates stem leakage. Unlike packing seals that require frequent maintenance, the bellow retains integrity over long-term use—critical for preventing oil or water loss in industrial systems.
• Dual Sealing Backup: Bellow (primary) and stem packing (secondary) form a redundant sealing system. If the bellow is damaged, the packing prevents immediate leakage, providing time for scheduled maintenance and avoiding unplanned shutdowns.
• Global Standard Compatibility: Flange dimensions comply with DIN and ANSI, fitting seamlessly into European and North American pipelines. This avoids adaptation issues in cross-border projects, simplifying installation and reducing costs.
• Precision Flow Regulation: The globe valve’s linear disc movement enables fine-tuned flow adjustment, with a linear flow characteristic that simplifies control of water or oil flow—essential for maintaining stable pressure in process systems.
• Robust Structural Design: Heavy-duty cast steel body resists deformation under pressure; Cr13 seat enhances wear resistance, ensuring long-term sealing performance even with frequent operation.

IV. Manufacturing Processes

• Material Validation: WCB and CF8 castings undergo ultrasonic testing to detect internal defects. Chemical analysis verifies alloy content (e.g., WCB carbon content ≤0.30%) to ensure mechanical strength.
• Bellow Forming: 304 stainless steel sheets are rolled into tubes, then hydraulically formed into corrugated bellows. TIG welding connects the bellow to the stem and bonnet, with helium leak testing (≤1×10⁻⁹ Pa·m³/s) to confirm hermetic sealing.
• Precision Machining: Valve body flow channels and flange faces are CNC-machined to DIN/ANSI dimensions, with bolt holes aligned to ±0.5mm tolerance. Disc and seat surfaces are ground to Ra ≤1.6μm for uniform contact and tight shutoff.
• Assembly & Testing:
  • Hydrostatic Test: Body tested at 1.5×rated pressure for 30 minutes; seat tested at 1.1×rated pressure with water to verify no leakage.
  • Operation Test: 100+ open/close cycles confirm smooth stem movement, with focus on linear regulation accuracy and sealing consistency.
  • Surface Treatment: The exterior is painted with anti-corrosion epoxy to resist rust, extending service life in humid or outdoor environments.