Descripción

N800 PN25 Double Offset Butterfly Valve with Duplex Stainless Steel 2205 Construction

El Double Offset Butterfly Valve DN800 PN25 is a high-performance valve designed for demanding industrial applications requiring reliable shutoff, low operating torque, and excellent corrosion resistance. Manufactured with a Duplex Stainless Steel ASTM A890 Grade 4A (2205) body and disc, this valve provides superior strength and resistance to chloride-induced corrosion, making it ideal for seawater, desalination, water treatment, offshore, and chemical processing systems.

Featuring a double eccentric (double offset) design, the valve minimizes seat wear during operation, significantly extending service life and reducing maintenance requirements. The resilient EPDM seat ensures bubble-tight sealing performance for water and non-oil applications, while the gear operator enables smooth and precise valve operation for large-diameter pipelines.

With a nominal size of DN800 (32 Inch) and a pressure rating of PN25, this valve is widely used in municipal water systems, industrial utilities, power plants, marine facilities, and infrastructure projects worldwide.

Product Overview

Product Gallery

What Is a Double Offset Butterfly Valve?

A double offset butterfly valve, also known as a válvula de mariposa doble excéntrica, incorporates two design offsets:

First Offset

The shaft is positioned behind the sealing surface centerline.

Second Offset

The shaft is offset from the pipeline centerline.

These offsets allow the disc to disengage from the seat immediately upon opening, reducing friction and seat wear.

Benefits of Double Offset Design

• Lower operating torque
• Longer seat life
• Reduced maintenance
• Improved sealing performance
• Better suitability for larger diameters
• Enhanced reliability in frequent cycling applications

Características clave

Duplex Stainless Steel 2205 Body & Disc

The valve body and disc are manufactured from Duplex Stainless Steel 2205, offering:

Exceptional Corrosion Resistance

Excellent resistance against:

• Seawater
• Brackish water
• Chlorides
• Industrial chemicals
• Coastal environments

High Mechanical Strength

Compared to conventional stainless steel:

• Nearly twice the yield strength of 316 stainless steel
• Better fatigue resistance
• Enhanced structural integrity

Longer Service Life

Ideal for demanding industrial and marine applications.

EPDM Resilient Seat

The EPDM seat provides:

• Bubble-tight shutoff
• Excellent water resistance
• Resistance to ozone and weathering
• Long sealing life
• Low operating torque

Suitable media include:

• Drinking water
• Cooling water
• Wastewater
• Treated water
• Air systems

Heavy-Duty Gear Operator

The enclosed gearbox provides:

• Smooth operation
• Reduced manual effort
• Accurate positioning
• Increased safety
• Reliable operation for large-diameter valves

The gear operator is especially important for DN800 valves where manual operation would require excessive torque.

Technical Advantages

Low Torque Operation

The double offset geometry significantly reduces friction between the disc and seat.

Benefits:

• Smaller actuators
• Reduced wear
• Easier operation
• Lower energy consumption

Zero Leakage Performance

The EPDM seat achieves reliable shutoff performance for water service applications.

Suitable for:

• Municipal water systems
• Desalination facilities
• Water treatment plants
• Industrial utility systems

Reduced Seat Wear

Unlike concentric butterfly valves, the disc contacts the seat only during final closure.

This results in:

• Longer seat life
• Lower maintenance costs
• Improved reliability

Especificaciones técnicas

Materials of Construction

Dimensional Range

Working Principle

6

The valve operates through quarter-turn rotation.

Opening

1. Gearbox rotates the shaft.
2. Disc moves away from the seat immediately.
3. Flow passage opens gradually.
4. Full flow is achieved at 90° rotation.

Closing

1. Disc rotates toward the seat.
2. Minimal friction occurs during travel.
3. Final seating creates a tight seal.
4. Flow is completely isolated.

Aplicaciones

Desalination Plants

Duplex 2205 construction provides excellent resistance to seawater corrosion.

Common applications:

• Intake systems
• Distribution pipelines
• Reverse osmosis plants
• Brine discharge systems

Municipal Water Supply

Suitable for:

• Transmission pipelines
• Water treatment plants
• Pump stations
• Distribution networks

Wastewater Treatment

Widely used in:

• Clarifier systems
• Effluent pipelines
• Sludge treatment systems
• Water recycling facilities

Offshore & Marine Industry

5

Installed in:

• Seawater cooling systems
• Ballast systems
• Firewater networks
• Offshore utility pipelines

Power Generation

Suitable for:

• Cooling water systems
• Condenser water pipelines
• Utility water service
• Auxiliary systems

Quality Assurance

Every valve is manufactured under strict quality control procedures.

Standard Tests

• Hydrostatic Shell Test
• Seat Leakage Test
• Functional Operation Test
• Material PMI Verification
• Dimensional Inspection
• Visual Examination

Testing complies with:

• EN 12266-1
• API 598

Available Options

Seat Materials

• EPDM
• NBR
• Viton (FKM)
• PTFE

Actuation Options

• Gear Operator
• Electric Actuator
• Pneumatic Actuator
• Hydraulic Actuator

Body Materials

• Duplex Stainless Steel 2205
• Super Duplex Stainless Steel 2507
• ASTM A216 WCB
• CF8
• CF8M

Frequently Asked Questions

What is the advantage of a double offset butterfly valve?

Double offset valves reduce seat friction, lower operating torque, and extend service life compared to concentric butterfly valves.

Why choose Duplex Stainless Steel 2205?

2205 offers excellent corrosion resistance, high strength, and superior performance in chloride-rich environments such as seawater systems.

Is EPDM suitable for drinking water?

Yes. EPDM is widely used in potable water, cooling water, and wastewater applications.

Why is a gear operator required for DN800 valves?

Large-diameter valves require significant operating torque. A gearbox ensures safe and efficient operation.

Can this valve be used in seawater systems?

Yes. Duplex Stainless Steel 2205 is one of the preferred materials for seawater and desalination applications.

Related Products

• Triple Offset Butterfly Valve
• Duplex 2205 Gate Valve
• Super Duplex Butterfly Valve
• Lug Type Butterfly Valve
• Válvula de mariposa tipo oblea
• Resilient Seated Butterfly Valve
• High Performance Butterfly Valve

Request a Quote

China DN800 PN25 Double Offset Butterfly Valve Manufacturer

We provide:

✅ Factory Direct Pricing
✅ OEM & Custom Manufacturing
✅ Fast Production Lead Times
✅ EN 10204 3.1 Material Certificates
✅ Third-Party Inspection Support
✅ Worldwide Project Experience

Send Your Inquiry Today

Please provide:

• Valve Size (DN800)
• Pressure Rating (PN25)
• Media Type
• Temperatura de funcionamiento
• Quantity Required
• Actuation Requirements

Our engineering team will provide a detailed quotation, datasheet, GA drawing, and delivery schedule within 24 hours.

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