Specification

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

I. Product Overview

As a key device for precise flow regulation and reliable shut-off in industrial pipeline systems, the Newway 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

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.

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.

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

Product Overview

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

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.

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.

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%.