Big Size Ductile Iron Pn10 DN400~DN2400 Pneumatic Electric Actuator Double Offset Eccentric Flange Butterfly Valve

Specification

TIANYU Ductile Iron Double-Offset Flanged Butterfly Valve: Intelligent Control Solution for Large-Diameter Industrial Pipelines

I. Product Overview

As a key flow regulation device in industrial pipeline systems, the TIANYU ductile iron double-offset flanged butterfly valve is specially designed for large-diameter pipelines. It adopts a double-offset structure and high-performance ductile iron, combined with electric/pneumatic actuators for precise control. With a diameter range of DN400-DN2400 (16″-96″) and pressure ratings of PN10-PN25, it stably manages water, sewage, air, gas, and other media within -20°C-120°C. Widely used in municipal water supply/drainage, wastewater treatment, power, and metallurgy, it complies with international standards such as ISO 5752, EN 593, and GB/T 12238.

II. Core Features: Perfect Integration of Double-Offset Technology and Ductile Iron

Double-Offset Structural Design
- Eccentric Principle: The stem axis deviates from both the seat centerline and disc center, forming double offsets. This design allows the disc to disengage from the seat rapidly when opening, reducing seal surface friction by 70% compared to ordinary butterfly valves.
- Sealing Performance: The 3D offset structure creates a line seal between the disc and seat. Paired with NBR/EPDM/PTFE elastic seals, it achieves ANSI FCI 70-2 Class VI (bubble-tight) sealing.
- Torque Optimization: The double-offset design significantly reduces opening/closing torque. The electric actuation torque for DN1000 is ≤800N·m, reducing energy consumption by 30% compared to similar products.
Advantages of Ductile Iron Material
- High Strength: QT400-15 ductile iron features tensile strength ≥400MPa, elongation ≥15%, and impact toughness ≥14J/cm², suitable for high-pressure difference conditions.
- Corrosion Resistance: The valve body uses epoxy coating (thickness ≥200μm), passing salt spray tests ≥1000 hours without rust, applicable to fresh water, seawater, and other media.
- Lightweight Design: 20% lighter than cast steel valves, reducing support structure costs. The DN1200 model weighs ≤1.2 tons.
Intelligent Drive System
- Actuator Configuration: Optional electric (AC220V/380V) or pneumatic (4-6bar) actuators. The electric actuator has IP68 protection and Ex d IIBT4 explosion-proof rating.
- Control Modes: Supports on/off type and regulating type (4-20mA analog), with optional smart positioners for PID regulation and ±1% accuracy.
- Remote Monitoring: Integrated with Modbus/TCP, Profibus, etc., enabling remote control and status feedback via SCADA systems.

III. Key Attributes: Technical Parameters and Standard Compliance

Attribute Category	Specific Parameters
Diameter Range	DN400-DN2400 (16″-96″), supporting non-standard customization (max DN3000)
Pressure Rating	PN10, PN16, PN25, compliant with EN 1092-1 and GB/T 9113 flange standards
Body Material	QT400-15 ductile iron, optional WCB cast steel, 304/316 stainless steel
Seal Material	NBR (-20°C-100°C), EPDM (-40°C-120°C), PTFE (-100°C-260°C)
Connection Type	Flanged (RF/FF), compliant with ISO 7005-1 and GB/T 9115 standards
Actuation Method	Electric (on/off/regulating), pneumatic (double-acting/single-acting), optional hydraulic
Manufacturing Standards	Design: ISO 5752, EN 593, GB/T 12238; Testing: API 598, ISO 5208; Certifications: CE, TSG
Suitable Media	Clean water, sewage, air, gas, steam, slurry, oil products, etc.

Product Overview

IV. Manufacturing Processes: Precision Control from Material to Finished Product

Ductile Iron Melting and Forming
- Precision Melting: Using cupola-electric furnace dual melting, strictly controlling C≥3.4%, Si≤2.8%, and Mg residual 0.03%-0.06% to ensure spheroidization rate ≥90%.
- Resin Sand Casting: Furan resin sand molding ensures CT7-level dimensional accuracy, wall thickness deviation ≤±1mm, eliminating shrinkage defects.
- Heat Treatment: Castings undergo 920°C annealing, hardness controlled at 150-180HBW to eliminate internal stress.
Precision Machining and Assembly
- CNC Machining: Processed by gantry 5-axis machining centers, disc and seat seal surfaces achieve IT7-level precision with surface roughness Ra≤0.8μm.
- Stem Treatment: 42CrMo alloy steel stem quenched and tempered (HRC28-32), hard chrome plated 0.05mm for 5x wear resistance.
- Assembly Testing: Each valve undergoes 1.5x nominal pressure shell testing and 1.1x seal testing; electric actuators are debugged for 100 cycles without jamming.
Quality Inspection System
- Material Certification: Each batch of ductile iron provides metallographic analysis reports (spheroidization rate ≥90%) and tensile test data (yield strength ≥250MPa).
- Nondestructive Testing: Magnetic particle inspection (MT) for stem surface cracks; ultrasonic testing (UT) for valve body internal defects.
- Performance Testing: KV value (flow coefficient) testing for DN1000+ valves with error ≤±5%.

Valve Details

V. Product Advantages: Core Competitiveness in Industrial Scenarios

Longevity and Reliability
The double-offset structure reduces seal wear. A DN1600 butterfly valve in a wastewater treatment plant operated for 12 years without seal replacement, reducing maintenance costs by 80% compared to ordinary valves.
Cost-Effectiveness Optimization
- Initial Investment: Ductile iron body costs 30% less than cast steel valves, with DN1200 models offering a price advantage of ¥250,000.
- Installation Cost: 20% lighter weight reduces lifting and foundation costs by 40%.
- Operation Energy Consumption: Electric actuator power is 30% lower than similar products, saving ~12,000 kWh annually (DN1000 model).
Customized Solutions
- Condition Adaptation: High-temperature graphite seals (≤450°C) for high-temperature conditions; hard alloy seal surfaces for particle-containing media.
- Functional Expansion: Special designs including fire-safe (API 607 certified), cryogenic (-40°C), and explosion-proof (ATEX certified).
- Connection Customization: Supports JIS, ANSI, ASME, etc., with non-standard flanges machined to drawings.
Global Service Support
Exported to 60+ countries, with 6 major warehouses in Europe, the Middle East, and Southeast Asia for 48-hour emergency response. Offering full lifecycle management, including selection consultation, installation guidance, and fault diagnosis.

Application

VI. Application Fields: Multi-industry Fluid Control Coverage

Municipal Water Supply/Drainage
- Flow regulation for urban water main pipes, DN2000 models used in South-North Water Diversion projects.
- Aeration systems in wastewater treatment plants, EPDM seals resisting ozone corrosion.
Power Industry
- Circulating water systems in thermal power plants, DN1800 valves reducing cooling water energy consumption by 15%.
- Nuclear power plant auxiliary pipelines, complying with ASME BPVC Section III nuclear standards.
Metallurgy and Mining
- Blast furnace gas pipeline flow control, designed for high pressure difference (≤0.8MPa).
- Mineral slurry transportation in concentrators, wear-resistant coated discs extending service life by 3x.
Paper and Chemical Industries
- Cooking liquor pipelines in paper mills, resistant to acid-base (pH 2-12).
- Inlet/outlet of chemical reactors, fast shut-off function ensuring production safety.