Double Flange Double Eccentric Butterfly Valve Manual Large Size 2-Way Soft Seal Butterfly Valve

Specification

TIANYU Double Flange Double-Offset Butterfly Valve: Customized Solution for Industrial Fluid Control

I. Product Overview

As a key device for precise flow regulation and reliable shut-off in industrial pipeline systems, the TIANYU double flange double-offset butterfly valve features an innovative double-offset structure, constructed from high-performance materials like ductile iron, cast steel, and stainless steel, paired with manual, electric, or pneumatic drive systems for versatile complex applications. With a diameter range of DN100-DN4000 (4″-160″) and PN10 pressure rating (Class 150LB), it stably controls media such as water, gases, and oil products within -20°C-120°C, complying with standards like GB/T 12238 and API 609. It serves as an ideal choice for municipal water supply/drainage, chemical, power, and metallurgical sectors.

II. Core Features: Double-Offset Technology and Sealing Innovation

Double-Offset Structural Design
- Eccentric Principle: The stem axis deviates from both the seat centerline and disc plane (radial offset 2-3mm, angular offset 5°), enabling the disc to disengage from the seat rapidly when opening, reducing seal surface friction by 60% compared to ordinary butterfly valves and extending service life significantly.
- Bidirectional Sealing: Combining elastic soft seals (EPDM/NBR/PTFE) with metal support structures achieves bidirectional bubble-tight sealing (leakage ≤0.01×DN mm³/s) without distinguishing media flow direction.
- Torque Optimization: The double-offset design reduces opening/closing torque by 40%, with manual operating torque for DN1000 ≤800N·m, suitable for large-diameter pipeline requirements.
Diversified Sealing System
- EPDM Seal: Resistant to -20°C-120°C warm water and air, suitable for municipal water supply/drainage and air conditioning systems.
- NBR Seal: Resistant to -40°C-100°C oil products, suitable for refinery circulating oil pipelines.
- PTFE Seal: Resistant to -100°C-260°C strong acids and alkalis, suitable for chemical reactor inlet/outlet control.
Flexible Drive Configuration
- Manual Worm Drive: Equipped with a gear reduction mechanism and optimized operation arm for easy opening/closing of large-diameter valves.
- Electric Actuator: Supports 4-20mA analog regulation, IP65 protection, and explosion-proof type complying with Ex d IIBT4 standards.
- Pneumatic Actuator: Optional double-acting/single-acting, response time ≤1.2 seconds, with spring return function for safety.

III. Key Attributes: Technical Parameters and Standard Compliance

Attribute Category	Specific Parameters
Diameter Range	DN100-DN4000 (4″-160″), supporting non-standard customization (max DN5000)
Pressure Rating	PN10 (1.0MPa), compliant with ASME B16.5 and EN 1092-1 flange standards
Body Material	QT450-10 ductile iron, WCB cast steel, CF8 (304)/CF8M (316) stainless steel, customizable to duplex steel 2205
Connection Type	Double flanged (RF raised face), bolt spacing compliant with GB/T 9113 and ANSI B16.5
Manufacturing Standards	Design: GB/T 12238, API 609; Testing: GB/T 13927, ISO 5208; Certifications: CE, TSG
Suitable Media	Clean water, sewage, air, natural gas, light oil products, weak acid-base solutions (pH 4-10)

Product Overview

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

Material Forming and Treatment
- Ductile Iron Melting: Using cupola-electric furnace dual process, adding rare earth magnesium alloy nodulizer to ensure nodulization rate ≥90%, graphite sphere diameter ≤0.05mm, and annealing at 900°C to eliminate internal stress, tensile strength ≥450MPa.
- Stainless Steel Casting: 304 material melted in vacuum induction furnace, passing intergranular corrosion test (ASTM A262 E method), with castings solution quenched at 1050°C to achieve grain size ≥Grade 5.
- Surface Treatment: Valve body sandblasted to Sa2.5, sprayed with epoxy powder (thickness ≥200μm), passing salt spray tests ≥1000 hours without rust.
Precision Machining and Assembly
- 5-Axis Machining: Disc and seat sealing surfaces processed by CNC grinder to surface roughness Ra≤0.8μm, flatness error ≤0.02mm, forming high-precision seal pairs.
- Stem Treatment: 2Cr13 stainless steel stem quenched and tempered (HRC28-32), chrome-plated 0.03mm for 5x wear resistance, ensuring 100,000 cycles without jamming.
- Assembly Testing: Each valve undergoes 1.5x nominal pressure shell testing (1.5MPa) and 1.1x seal testing (1.1MPa), holding pressure for 15 minutes without leakage.
Quality Control System
- Nondestructive Testing: 100% ultrasonic testing (UT) for DN≥500 valves, magnetic particle inspection (MT) for key welds.
- Material Certification: Each batch of steel provides spectral analysis reports and tensile test data (e.g., QT450-10 yield strength ≥310MPa).
- Life Testing: Sampling for 50,000 cycle tests, seal wear ≤0.1mm, torque decay ≤10%.

Valve Details

V. Product Advantages: Core Value in Industrial Scenarios

Long Service Life and Low Maintenance
The double-offset structure reduces seal wear. A DN1200 butterfly valve in a municipal project operated for 8 years without seal replacement, extending maintenance cycles by 3 times and decreasing annual costs by 60%. Ductile iron body weight is 25% lighter than cast steel, reducing installation costs by 30%.
Full-scenario Customization
- Diameter Customization: Full coverage of DN100-DN4000, with split disc design for DN2000+ to solve casting challenges.
- Condition Adaptation:
  - Seawater systems: 316L stainless steel + fluoroelastomer seal, resistant to Cl⁻≤3000ppm.
  - Dust environments: Tungsten carbide-coated discs, wear rate ≤0.01mm/year.
  - Cryogenic LNG: LCB low-temperature steel + nickel-based alloy seal, stable operation at -196°C.
Cost-Efficiency Balance
- Initial Investment: Double flange design costs 15% less than lug type, with DN1000 models offering a price advantage of ¥20,000.
- Operation Efficiency: Electric actuator power is 20% lower than similar products, achieving ±1% regulation accuracy with smart positioners.
- Installation Convenience: Flange connection compatible with multiple standards, reducing on-site installation time by 40% compared to wafer type.
Global Service Support
Exported to 30+ countries, validated in Kazakhstan water transmission projects and Saudi oilfield associated gas pipelines. Providing 7×24-hour technical response, overseas warehouses stocking DN100-DN600 regular accessories, and emergency orders delivered within 48 hours.

Application

VI. Application Fields: In-depth Industry Coverage

Municipal Engineering
- Sectional control for urban water main pipes, DN2000 models used in South-North Water Diversion supporting projects.
- Aeration tank air volume regulation in wastewater treatment plants, EPDM seals resisting ozone corrosion.
Petrochemical Industry
- Circulating oil pipelines in refinery atmospheric-vacuum units, NBR seals resisting 100°C light oil products.
- Acid-base storage tank inlet/outlet in chemical parks, PTFE seals resisting 98% sulfuric acid.
Power Energy Sector
- Circulating water system (DN1600) flow distribution in thermal power plants, pneumatic actuators enabling automatic regulation with DCS systems.
- Fuel gas pipeline fast shut-off for gas turbines, electric actuator response time ≤1 second.
Metallurgy and Mining
- Blast furnace gas pipeline shut-off (dust content ≤50mg/m³), wear-resistant coated discs reducing dust jamming.
- Mineral slurry transportation in concentrators (solid particles ≤30μm), ductile iron body offering outstanding cost-performance.