TIANYU WCB Body SS316 Disc Double Offset Butterfly Valve – DN500 150LB Wafer Type NBR Soft Seal Valve for Industrial Fluid Control with API 609 Compliance

I. Product Overview

II. Key Attribute Specifications

A. Dimensional & Pressure-Temperature Parameters

• Port Size: DN500 (20”), with a size range of DN50 to DN1200 (2” to 48”) to accommodate diverse pipeline requirements. The double offset design enables full-bore flow when open, minimizing pressure drop (Cv value up to 1200 for DN500).
• Pressure Rating: 150LB (PN20), suitable for medium-pressure industrial systems. Hydrostatic testing follows API 598: 1.5× rated pressure (300LB/PN30) for the valve body and 1.1× rated pressure (165LB/PN22) for the seat, ensuring no leakage or structural deformation.
• Temperature Range: -20℃ to 120℃, dictated by NBR seal compatibility—covering most industrial fluids, water, and lubricating oils within moderate temperature thresholds.

B. Material Composition

• Valve Body: WCB Carbon Steel (ASTM A216), a cast alloy with high tensile strength (≥485MPa) and excellent machinability. It is optimized for corrosion resistance in non-aggressive media, with a gray epoxy paint coating for external protection.
• Butterfly Disc: SS316 Stainless Steel (ASTM A182), containing 16-18% chromium, 10-14% nickel, and 2-3% molybdenum. This alloy provides superior corrosion resistance in acidic, saline, and chemical environments, ensuring long-term durability in harsh media.
• Sealing Material: NBR (Nitrile Butadiene Rubber) soft seal, bonded to the valve seat. NBR excels in oil resistance and moderate temperature tolerance, making it ideal for hydrocarbon and industrial fluid applications.
• Valve Stem: SS316 Stainless Steel, featuring an anti-blowout design, polished finish (Ra ≤0.8μm) to reduce packing friction, and corrosion resistance in wet or chemical environments.
• Wafer Flanges & Fasteners: Integral WCB flanges (machined to ASME B16.5 standards) and SS316 bolts/nuts ensure structural integrity and corrosion resistance in industrial settings.

C. Connection & Operational Features

• Connection Type: Wafer Type (ASME B16.5), designed for installation between two pipeline flanges with through-bolts—simplifying alignment and reducing installation time in industrial piping systems.
• Operation Mode: Manual (worm gear operator as standard) with optional pneumatic, electric, or hydraulic actuation. The worm gear operator reduces torque by 5-10 times, enabling single-person operation of DN500 valves.
• Functional Features:
  • Double Offset Geometry: The disc is offset from the seat centerline in two planes, allowing it to lift off the seat during opening/closing—minimizing friction and extending seal life by 3-5 times compared to concentric designs.
  • Soft Seal Integrity: NBR lining achieves ANSI/FCI Class VI leakage performance, preventing media loss in oil, chemical, and water applications.
  • Corrosion Resistance: SS316 disc and WCB body with epoxy coating resist corrosion from industrial fluids, saline water, and mild chemicals.

D. Certifications & Compliance

• Design & Manufacturing Standards: API 609, ASME B16.34, ASME B16.5.
• Quality & Safety Certifications: ISO 9001, CE.
• Performance Certifications: ANSI/FCI Class VI (leakage), ISO 6283 (flow coefficient testing).

III. Feature Description

A. Double Offset Design: Friction Reduction & Seal Longevity

• Seat Disengagement: As the disc rotates, it lifts off the seat, eliminating sliding friction—reducing wear on both the disc and seal. In a chemical plant’s solvent transfer line, this design extended seal life from 18 months to 5 years.
• Low Operational Torque: The eccentric geometry reduces torque by 40-60% compared to concentric butterfly valves. A DN500 manual model requires only 150 N·m of torque, enabling easy operation without auxiliary tools.
• Bidirectional Sealing: The design supports reliable shut-off in both flow directions, simplifying pipeline design and eliminating installation direction constraints.

B. Material Synergy: Corrosion Resistance & Durability

• WCB Body: Its robust construction withstands mechanical stress in industrial pipelines, while the epoxy coating protects against external corrosion in outdoor or buried installations. In a refinery’s oil feed line, WCB valves operated reliably for 8 years, whereas cast iron alternatives failed due to corrosion within 2 years.
• SS316 Disc: The alloy’s molybdenum content provides exceptional resistance to chloride-induced corrosion, making it ideal for coastal water treatment or chemical processing with saline media. In a seawater desalination plant, SS316 discs showed no signs of corrosion after 7 years of service.
• NBR Soft Seal: Nitrile rubber’s oil resistance and moderate temperature tolerance make it suitable for hydrocarbon fluids (e.g., diesel, lubricating oil) and industrial chemicals. In an automotive manufacturing plant’s coolant line, NBR seals maintained integrity for 4 years, outperforming EPDM in oil-rich environments.

C. Wafer Connection: Installation Efficiency

• Space Optimization: The compact design requires minimal axial space, making it ideal for crowded industrial piping racks or retrofitting older systems.
• Easy Maintenance: Valves can be removed for repair or replacement without disassembling adjacent pipeline flanges, reducing downtime in continuous-process industries.
• Cost-Effectiveness: Wafer valves eliminate the need for dedicated valve flanges, reducing hardware and installation costs by 20-30% compared to flanged valves.

D. Soft Seal Performance: Leak-Tight Reliability

• Bubble-Tight Sealing: ANSI/FCI Class VI performance ensures ≤0.1×DN mm³/min leakage—critical for preventing product loss in chemical processing or environmental contamination in water systems.
• Resilience to Minor Damage: The rubber seal’s elasticity compensates for minor misalignments or surface imperfections, maintaining sealing integrity in systems with occasional vibrations or thermal expansion.
• Chemical Compatibility: NBR resists most oils, fuels, and aliphatic hydrocarbons, making it a versatile choice for industrial fluid control.

IV. Manufacturing Processes

A. Material Inspection & Preparation

• WCB Verification: Spectral analysis confirms chemical composition, and ultrasonic testing detects internal defects. Mechanical testing ensures compliance with ASTM A216.
• SS316 Validation: Disc blanks are tested for chemical composition (Cr, Ni, Mo content) and hardness to ensure corrosion and wear resistance.
• NBR Checks: Rubber is tested for hardness, tensile strength, and elongation to ensure sealing integrity and durability.

B. Valve Body & Disc Fabrication

• Body Manufacturing: WCB bodies are sand-cast, heat-treated for strength, and CNC-machined to ASME B16.5 flatness and surface finish standards.
• Disc Fabrication: SS316 discs are precision-turned and milled to achieve the double offset geometry, with a sharp yet durable edge profile.
• Seal Application: NBR rubber is bonded to the seat area via heat and pressure, ensuring uniform thickness and adhesion.

C. Assembly & Quality Testing

• Stem & Disc Assembly: The SS316 stem is keyed to the disc, tested for concentricity (runout ≤0.1mm).
• Hydrostatic Testing: Per API 598, the body is tested at 1.5× 150LB, and the seat at 1.1× 150LB, with no leakage allowed.
• Operational Testing: The valve is cycled 100 times to verify smooth operation, torque, and seal integrity.

D. Final Inspection & Documentation

• Visual Inspection: Checks for surface defects, proper marking, and compliance with ASME B16.34.
• Documentation: Includes MTRs, hydrostatic test reports, and compliance certificates (API 609, ISO 9001).

V. Product Advantages

A. Extended Service Life in Harsh Media

B. Low Operational Costs

C. Leak-Tight Reliability for Industrial Fluids

D. Easy Installation & Maintenance

E. Versatility Across Industrial Sectors

VI. Product Applications

A. Chemical & Petrochemical Industry

• Chemical Processing: Regulates flow of acids, solvents, and intermediates with SS316 disc’s corrosion resistance and NBR’s chemical compatibility.
• Petrochemical Refining: Controls fuel oil, lubricants, and hydrocarbon flow with WCB’s strength and NBR’s oil resistance.
• Pharmaceutical Manufacturing: Manages purified water and process fluids with cleanable surfaces and leak-tight sealing.

B. Oil & Gas Industry

• Upstream Production: Controls produced water and oil flow in wellhead systems with SS316’s corrosion resistance.
• Midstream Transmission: Regulates pipeline flow of natural gas liquids with low-torque operation and bidirectional sealing.
• Downstream Refining: Manages refinery process streams with WCB’s durability and NBR’s oil tolerance.

C. Power Generation

• Thermal Power Plants: Regulates cooling water and steam condensate flow with WCB’s strength and NBR’s temperature tolerance.
• Nuclear Power Plants: Controls service water flow with SS316’s radiation resistance and leak-tight sealing.
• Renewable Energy: Manages biogas flow in anaerobic digesters with corrosion-resistant materials.

D. Municipal & Industrial Water Systems

• Potable Water Distribution: Controls city water mains with leak-tight sealing and corrosion resistance.
• Wastewater Treatment: Manages sewage and effluent flow with durable materials and easy maintenance.
• Industrial Water Circulation: Regulates process water and cooling fluid flow in manufacturing facilities.

E. General Industrial Manufacturing

• Automotive: Controls coolant and lubricant flow in assembly plants with NBR’s oil resistance.
• Food & Beverage: Manages water and cleaning fluid flow with cleanable surfaces (optional EPDM seal for FDA compliance).
• Mining: Regulates process water and slurry flow with robust WCB construction (optional hard seal for abrasive media).

VII. Customization Advantage