U- section Flanged Double Offset Butterfly Valve for Seawater Service
U- section Flanged Double Offset Butterfly Valve for Seawater Service - Image 2

U- section Flanged Double Offset Butterfly Valve for Seawater Service

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Description

Wafer-Type Double Eccentric Butterfly Valve Technical Data Sheet

(U-Section Body, Series 20 Face-to-Face)

Product Name: Wafer-Type Double Eccentric Butterfly Valve (U-Section)
Model: D342F46 / D342V (Custom Series)
Date: February 16, 2026

1. Product Overview

This valve is specifically designed for desalination plants, highly corrosive chemical media, and demanding marine engineering environments. It features a U-section body for precise centering between flanges and a double eccentric design to ensure low operating torque and extended service life. The face-to-face dimensions conform to ISO 5752 Series 20 (short pattern). Critical components are manufactured from high-performance corrosion-resistant alloys.

2. General Technical Specifications

Item Specification
Valve Type Wafer-Type, Double Eccentric (Double Offset) Butterfly Valve
Body Style U-Section (Centering collar type for wafer installation)
Nominal Diameter (DN) DN80 ~ DN1200 (Customizable upon request)
Nominal Pressure (PN) PN10 / PN16 / Class 150LB
Face-to-Face Dimension ISO 5752 Series 20 (Short pattern / API 609 Category B)
Structure Style Double Eccentric (Double Offset)
Connection Type Wafer-Type (Centering via U-section body, fits between EN1092-2 / ASME B16.5 flanges)
Temperature Range -20°C ~ +200°C (-4°F ~ +392°F) (Depending on Viton compound)
Applicable Media Highly corrosive media, seawater, brine, acids, alkalis, steam, and hydrocarbons.
Design Standard GB/T 12238 / API 609 / EN593
Pressure Testing GB/T 13927 / API 598
Operation Worm Gear, Electric Actuator, Pneumatic Actuator

3. Material of Parts Specification

Part Name Material / Grade Material Properties & Application
Body Ductile Iron (QT450-10 / GGG40.3) High strength, good toughness. Epoxy coated internally/externally.
Disc Aluminum Bronze C95800 (ASTM B148) Nickel-Aluminum Bronze. Extremely high resistance to seawater corrosion and impingement attack.
Stem / Shaft Monel K500 (UNS N05500) Nickel-Copper alloy. Superior corrosion resistance in seawater and high strength.
Seat (Seal Ring) Fluoroelastomer (FKM / Viton) High-temperature resistance. Excellent resistance to strong acids, bases, and solvents.
Shaft Bearings PTFE / Bronze Prevents galvanic corrosion and reduces friction.
Stem Seals Viton / Flexible Graphite Ensures zero leakage at the stem area.
Body Coating Epoxy Resin (Blue) Minimum thickness 250µm, anti-corrosion.

4. Main Technical Characteristics

  1. Double Eccentric Design: The stem offset allows the disc to disengage from the seat immediately upon opening, eliminating rubbing and wear.

  2. U-Section Body: The precision-machined U-shaped circumference ensures perfect centering between pipeline flanges, preventing misalignment and gasket damage.

  3. Series 20 Face-to-Face: Conforms to the short pattern (ISO 5752-20 / API 609 Cat. B), allowing direct replacement of existing valves and saving installation space.

  4. Corrosion-Resistant Trim (C95800 + Monel K500): Specifically selected for maximum service life in seawater and chemical applications.

  5. Zero Leakage Sealing: Viton seat provides bubble-tight shut-off (Class VI).

5. Principal Dimensions & Connection Data (PN16 / Series 20)

Note: Final dimensions subject to approval drawings.

Nominal Size DN Face-to-Face L (mm) ISO 5752-20 Body U-Section Diameter (approx.) Flange Compatibility (Bolt Circle) Gearbox Type (Ref.)
100 52 132 mm Fits PN10/16 Flanges BA-1
150 56 184 mm Fits PN10/16 Flanges BA-2
200 60 236 mm Fits PN10/16 Flanges BA-3
250 68 284 mm Fits PN10/16 Flanges BA-4
300 78 340 mm Fits PN10/16 Flanges BA-4
400 102 445 mm Fits PN10/16 Flanges BA-5
500 127 550 mm Fits PN10/16 Flanges BA-6
600 154 656 mm Fits PN10/16 Flanges BA-7

Note: The U-Section body is designed to center inside the flange bolt circle, standard for wafer butterfly valves.

6. Applicable Standards & Testing

  • Design & Manufacture: GB/T 12238 / API 609 / EN593

  • Face-to-Face: ISO 5752 Series 20 (Short pattern)

  • Flange Compatibility: EN 1092-2, ASME B16.5 (via wafer mounting)

  • Pressure Tests:

    • Shell: 1.5 × Rated Pressure (PN)

    • Seat: 1.1 × Rated Pressure (PN) (Bi-directional zero leakage per ISO 5208 Rate A / API 598)

7. Remarks

  • This U-section body with Series 20 face-to-face is the industry standard for wafer-type butterfly valves and ensures interchangeability.

  • This specific material combination (C95800 Disc + Monel K500 Stem + Viton Seat) is the preferred choice for seawater and high-corrosion applications.

  • Ensure flange bolts are centered correctly using the U-section body profile during installation.

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