High-Performance DN80 Class 150 WCB Soft-Sealed Lug-Type Double Eccentric Butterfly Valve

TIANYU 3” Class 150 WCB lug-type double eccentric butterfly valve is a technologically advanced flow control device engineered to address the challenges of industrial fluid management. As a double eccentric butterfly valve, it features a unique offset design that minimizes friction between the disc and seat, delivering extended service life and reliable sealing—even in demanding applications. Constructed from WCB carbon steel (ASTM A216), this valve adheres to international standards such as API 609, ASME B16.5, and ISO 5752, ensuring compatibility with global industrial pipelines.

The lug-type flange connection enables flexible installation, while the soft-sealed design provides leak-tight performance (ANSI/FCI Class IV~VI). Equipped with an electric actuator (with manual override), it supports automated and remote operation—ideal for process-critical systems in oil, gas, chemical, and power industries. Whether regulating flow in pipelines, isolating process streams, or managing industrial fluids, this valve embodies durability, efficiency, and operational reliability.

II. Key Attribute Specifications

A. Dimensional & Pressure-Temperature Parameters

Port Size: 3” (DN80), a widely adopted size in industrial pipelines that balances flow capacity and installation flexibility. Suitable for medium-scale process lines in refineries, chemical plants, and water distribution networks.
Pressure Rating: Class 150 (2.0MPa), aligned with industrial medium-pressure requirements. The valve undergoes hydrostatic testing at 1.5× rated pressure for the body and 1.1× rated pressure for the seat, ensuring structural integrity and leak-tight sealing under operating conditions.
Temperature Range: -20℃ to 200℃, enabled by WCB carbon steel’s thermal stability and compatible soft-sealing materials (e.g., EPDM, PTFE). This range accommodates ambient media, moderately heated fluids, and low-temperature industrial applications.

B. Material Composition

Valve Body & Disc: WCB carbon steel (ASTM A216), offering tensile strength of 485–655MPa and yield strength ≥240MPa. This material withstands moderate corrosion, thermal stress, and mechanical impact in oil, gas, water, and steam services.
Sealing System: Soft seals (EPDM or PTFE), providing chemical resistance and bubble-tight sealing. EPDM suits general industrial media (water, air, mild chemicals), while PTFE extends compatibility to aggressive acids, alkalis, and solvents.
Valve Stem: Alloy steel (17-4PH or 410SS), precision-machined for strength and corrosion resistance, with an anti-blowout design to meet safety standards.
Lug Flanges: WCB carbon steel, machined to ANSI B16.5 specifications for seamless integration with standard pipeline flanges.

C. Connection & Operational Features

Connection Type: Lug-type flange (ANSI B16.5), allowing bolt-through installation that simplifies alignment and eliminates the need for pipeline rotation during maintenance. Lug-style connections are also ideal for retrofitting, as they can be installed between existing flanges.
Operation Mode: Electric actuation (with manual override) as standard. The electric actuator enables automated control (e.g., via SCADA/DCS systems), while the manual override ensures operation during power outages—critical for process-critical applications.
Safety & Compliance Features: API 609-compliant design, with optional fire-safe and low-emission configurations. The valve is permanently marked for material traceability and compliance with industry regulations.

D. Certifications & Compliance

Industry Standards: API 609, ASME B16.5, ISO 5752, ISO 9001.
Material Certifications: ASTM A216 (WCB), ASTM A564 (17-4PH).
Regional Approvals: CE, ATEX (optional for hazardous environments).

III. Feature Description

A. Double Eccentric Design: Reduced Wear & Extended Service Life

The double eccentric (offset) design is the hallmark of this valve, setting it apart from concentric or single-eccentric alternatives. By offsetting the disc’s axis from both the valve body’s center and the seat’s sealing face, the disc lifts away from the seat during the opening/closing stroke—eliminating contact for over 90% of the movement. This drastically reduces friction and wear, extending the seal’s service life by 2–3 times compared to concentric butterfly valves.

In applications with frequent cycling (e.g., chemical batch processing), this design ensures consistent sealing performance over thousands of cycles. For example, in a refinery’s gasoline blending system, the double eccentric valve maintained ANSI Class IV leakage after 10,000 cycles, while a single-eccentric valve required seal replacement after 3,000 cycles.

B. WCB Carbon Steel Construction: Durability in Industrial Environments

WCB carbon steel is a workhorse material for industrial valves, offering a balance of strength, cost-effectiveness, and weldability. It withstands pressures up to Class 150 and temperatures up to 200℃, making it suitable for oil, gas, steam, and water services. Unlike exotic alloys, WCB is readily available and economical—ideal for large-scale projects where cost control is critical.

In a power plant’s cooling water system, a WCB butterfly valve operated reliably for 8 years, resisting corrosion from treated water and mechanical stress from pipeline vibrations. Its weldability also allows for on-site repairs, a significant advantage in remote or offshore installations.

C. Lug-Type Flange Connection: Installation Flexibility & Maintenance Ease

Lug-type flanges offer distinct advantages over wafer or wafer-style flanges:

Bolt-Through Installation: Lug flanges are drilled to allow bolts to pass through the valve and into the pipeline flanges, simplifying alignment and reducing installation time. This is especially beneficial in confined spaces or when retrofitting into existing systems.
Isolation Capability: Lug valves can be installed with blind flanges on one side, enabling easy isolation for maintenance without disrupting the entire pipeline. In a chemical plant’s batch reactor feed line, this feature allows for quick valve inspection, minimizing downtime.
Compatibility: Lug flanges conform to ASME B16.5, ensuring compatibility with standard pipeline flanges from other manufacturers. This interchangeability reduces inventory costs and streamlines procurement for multi-vendor projects.

D. Soft-Sealed Performance: Leak-Tight Media Containment

The soft-sealed design, typically using EPDM or PTFE, delivers ANSI/FCI Class IV~VI leakage performance—meaning minimal to no media loss. EPDM is suitable for general industrial media (water, air, lubricating oils), while PTFE extends compatibility to aggressive chemicals (e.g., sulfuric acid, sodium hydroxide).

In a pharmaceutical facility’s API manufacturing line, a PTFE-sealed valve maintained bubble-tight performance, preventing product contamination and ensuring compliance with FDA regulations. Even under temperature fluctuations and cyclic operation, the soft seal retains its elasticity, ensuring long-term reliability.

E. Electric Actuation with Manual Override: Automation & Safety

The electric actuator enables automated control, integrating seamlessly with SCADA/DCS systems for remote monitoring and process optimization. In a chemical plant’s solvent recovery system, the valve is programmed to open/close based on tank level sensors, reducing manual labor and operational errors.

The manual override feature ensures the valve can be operated during power outages or actuator failures—a critical safety measure for process-critical applications. In an oil refinery’s emergency shutdown system, operators can manually close the valve to prevent hydrocarbon leaks, mitigating environmental and safety risks.

High-Performance DN80 Class 150 WCB Soft-Sealed Lug-Type Double Eccentric Butterfly Valve

IV. Manufacturing Processes

A. Material Inspection & Preparation

WCB Verification: Raw material billets undergo spectral analysis to confirm chemical composition (C: 0.25–0.35%, Mn: 0.60–1.00%) and ultrasonic testing to detect internal defects. Mechanical testing (tensile, impact) ensures compliance with ASTM A216 standards.
Seal Material Testing: EPDM/PTFE seals are tested for compression set, tensile strength, and chemical resistance to ensure they meet industrial or sanitary-grade requirements.

B. Valve Body & Disc Machining

Casting: The valve body and disc are produced via sand casting for WCB carbon steel, ensuring dimensional accuracy and a robust structure. Castings are normalized to relieve internal stresses, enhancing durability.
Machining: CNC turning and milling centers shape the body, disc, and lug flanges. The double eccentric disc is precision-machined to ensure the offset dimensions are within ±0.05mm, critical for proper sealing and reduced wear. Flange faces are machined to flatness tolerance ≤0.05mm/m and surface finish Ra ≤3.2μm for proper gasket seating.

C. Sealing & Actuator Integration

Seal Installation: Soft seals (EPDM/PTFE) are precision-cut and installed into the valve body, with spring-loading to compensate for thermal expansion and wear. The disc’s sealing edge is lapped to ensure uniform contact with the seal.
Actuator Mounting: The electric actuator is mounted to the valve via an ISO 5211 adapter flange. The drive shaft is connected to the valve stem, with laser alignment to ensure coaxiality and smooth operation. Actuator controls are calibrated to match the valve’s torque requirements, ensuring reliable actuation.

D. Quality Testing & Certification

Hydrostatic Testing: The valve undergoes shell and seat tests at 1.5× and 1.1× rated pressure, respectively, with no leakage allowed.
Operational Testing: The valve is cycled 100 times to verify smooth operation, torque consistency, and seal integrity. Leakage is measured using a bubble counter to confirm ANSI/FCI Class IV~VI performance.
Documentation: Material test reports, hydrostatic test reports, and compliance certificates (API 609, ISO 9001) are provided for each valve.

V. Product Advantages

A. Extended Service Life

The double eccentric design reduces friction between the disc and seat, extending the seal’s service life by 2–3 times compared to single-eccentric or concentric valves. This translates to lower maintenance costs and fewer unplanned shutdowns.

B. Reliable Leak-Tight Sealing

Soft-sealed construction delivers ANSI/FCI Class IV~VI leakage performance, ensuring media containment in critical applications. This reduces the risk of environmental spills, product contamination, and regulatory non-compliance.

C. Flexible Installation & Maintenance

Lug-type flanges simplify installation and maintenance, reducing downtime and labor costs. In retrofitting projects, they eliminate the need to modify existing pipelines, saving time and resources.

D. Cost-Effective Performance

WCB carbon steel offers a favorable balance of cost and durability, making the valve an economical choice for large-scale industrial projects. Its compatibility with standard flanges and actuators further reduces procurement and inventory costs.

E. Versatility Across Industries

Suitable for oil, gas, chemical, power, water, and general industrial applications, the valve eliminates the need for multiple valve types—simplifying inventory management and operational workflows.

VI. Product Applications

A. Oil & Gas Industry

Midstream Pipelines: Controls flow of crude oil, natural gas, and refined products in transmission and distribution lines. The double eccentric design ensures reliable sealing in high-cyclic operation scenarios.
Refining Processes: Regulates flow of hydrocarbons, steam, and cooling water in refinery units. WCB construction withstands moderate corrosion from process fluids.

B. Chemical Processing

Batch Reactors: Manages flow of chemicals, solvents, and catalysts in batch processing systems. Soft-sealed PTFE options resist aggressive media like acids and alkalis.
Wastewater Treatment: Handles corrosive effluents in chemical wastewater plants, with WCB providing durability against harsh environments.

C. Power Generation

Cooling Water Systems: Regulates flow of cooling water in thermal and nuclear power plants. The valve’s durability ensures reliable operation in continuous-process environments.
Steam & Condensate Lines: Controls flow of steam and condensate in boiler and turbine auxiliary systems, with WCB supporting high-temperature service.

D. Water & Wastewater Treatment

Municipal Water Distribution: Manages flow in potable water mains, with EPDM seals ensuring water quality and leak-tight performance.
Industrial Wastewater: Handles abrasive and corrosive wastewater in manufacturing facilities, with the double eccentric design reducing wear from solids-laden media.

E. General Industrial Applications

Manufacturing Plants: Controls flow of process fluids, lubricants, and cooling agents in automotive, electronics, and machinery manufacturing.
Food & Beverage: With sanitary modifications (e.g., EPDM seals, polished surfaces), the valve suits food-grade applications like beverage bottling and dairy processing.

VII. Customization

TIANYU 3” Class 150 WCB lug-type double eccentric butterfly valve delivers extended service life, reliable sealing, and flexible installation for oil, gas, chemical, and industrial applications. It combines double eccentric design, WCB durability, lug-type versatility, and soft-sealed performance, backed by API/ASME standards.

Customize with 304/316 stainless steel for corrosion resistance, PTFE/EPDM seals for media compatibility, electric/pneumatic/hydraulic actuators, or fire-safe configurations. Tailor to your pressure, temperature, and automation needs for optimal performance.